Code:
/ Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / whidbey / netfxsp / ndp / fx / src / WinForms / Managed / System / WinForms / NativeWindow.cs / 4 / NativeWindow.cs
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//-----------------------------------------------------------------------------
/*
*/
namespace System.Windows.Forms {
using System.Threading;
using System.Configuration.Assemblies;
using System.Runtime.Remoting;
using System.Runtime.InteropServices;
using System.Runtime.ConstrainedExecution;
using System.Runtime.CompilerServices;
using System.Reflection;
using System.Security;
using System.Security.Permissions;
using System.Diagnostics;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using System.ComponentModel;
using Microsoft.Win32;
using System.Text;
using System.Globalization;
using System.Diagnostics.CodeAnalysis;
///
///
/// Provides a low-level encapsulation of a window handle
/// and a window procedure. The class automatically manages window class creation and registration.
///
///
[
SecurityPermission(SecurityAction.InheritanceDemand, Flags = SecurityPermissionFlag.UnmanagedCode),
SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)
]
public class NativeWindow : MarshalByRefObject, IWin32Window {
#if DEBUG
private static readonly BooleanSwitch AlwaysUseNormalWndProc = new BooleanSwitch("AlwaysUseNormalWndProc", "Skips checking for the debugger when choosing the debuggable WndProc handler");
private static readonly TraceSwitch WndProcChoice = new TraceSwitch("WndProcChoice", "Info about choice of WndProc");
#else
private static readonly TraceSwitch WndProcChoice;
#endif
/**
* Table of prime numbers to use as hash table sizes. Each entry is the
* smallest prime number larger than twice the previous entry.
*/
private readonly static int[] primes = {
11,17,23,29,37,47,59,71,89,107,131,163,197,239,293,353,431,521,631,761,919,
1103,1327,1597,1931,2333,2801,3371,4049,4861,5839,7013,8419,10103,12143,14591,
17519,21023,25229,30293,36353,43627,52361,62851,75431,90523, 108631, 130363,
156437, 187751, 225307, 270371, 324449, 389357, 467237, 560689, 672827, 807403,
968897, 1162687, 1395263, 1674319, 2009191, 2411033, 2893249, 3471899, 4166287,
4999559, 5999471, 7199369
};
const int InitializedFlags = 0x01;
const int DebuggerPresent = 0x02;
const int UseDebuggableWndProc = 0x04;
const int LoadConfigSettings = 0x08;
const int AssemblyIsDebuggable = 0x10;
// do we have any active HWNDs?
//
[ThreadStatic]
static bool anyHandleCreated;
static bool anyHandleCreatedInApp;
const float hashLoadFactor = .72F;
private static int handleCount;
private static int hashLoadSize;
private static HandleBucket[] hashBuckets;
private static IntPtr userDefWindowProc;
[ThreadStatic]
private static byte wndProcFlags = 0;
[ThreadStatic]
private static byte userSetProcFlags = 0;
private static byte userSetProcFlagsForApp;
//nned to Store Table of Ids and Handles
private static short globalID = 1;
private static Dictionary hashForIdHandle;
private static Dictionary hashForHandleId;
private static object internalSyncObject = new object();
private static object createWindowSyncObject = new object();
#if DEBUG
AppDomain handleCreatedIn = null;
string subclassStatus = "None";
#endif
IntPtr handle;
NativeMethods.WndProc windowProc;
IntPtr windowProcPtr;
IntPtr defWindowProc;
bool suppressedGC;
bool ownHandle;
NativeWindow previousWindow; // doubly linked list of subclasses.
NativeWindow nextWindow;
WeakReference weakThisPtr;
static NativeWindow() {
EventHandler shutdownHandler = new EventHandler(OnShutdown);
AppDomain.CurrentDomain.ProcessExit += shutdownHandler;
AppDomain.CurrentDomain.DomainUnload += shutdownHandler;
// Initialize our static hash of handles. I have chosen
// a prime bucket based on a typical number of window handles
// needed to start up a decent sized app.
int hashSize = primes[4];
hashBuckets = new HandleBucket[hashSize];
hashLoadSize = (int)(hashLoadFactor * hashSize);
if (hashLoadSize >= hashSize) {
hashLoadSize = hashSize - 1;
}
//Intilialize the Hashtable for Id...
hashForIdHandle = new Dictionary();
hashForHandleId = new Dictionary();
}
public NativeWindow() {
weakThisPtr = new WeakReference(this);
}
///
/// Override's the base object's finalize method.
///
~NativeWindow() {
ForceExitMessageLoop();
}
///
/// This was factored into another function so the finalizer in control that releases the window
/// can perform the exact same code without further changes. If you make changes to the finalizer,
/// change this method -- try not to change NativeWindow's finalizer.
///
internal void ForceExitMessageLoop() {
IntPtr h;
bool ownedHandle;
//
lock (this) {
h = handle;
ownedHandle = ownHandle;
}
if (handle != IntPtr.Zero) {
//now, before we set handle to zero and finish the finalizer, let's send
// a WM_NULL to the window. Why? Because if the main ui thread is INSIDE
// the wndproc for this control during our unsubclass, then we could AV
// when control finally reaches us.
if (UnsafeNativeMethods.IsWindow(new HandleRef(null, handle))) {
int lpdwProcessId; //unused
int id = SafeNativeMethods.GetWindowThreadProcessId(new HandleRef(null, handle), out lpdwProcessId);
Application.ThreadContext ctx = Application.ThreadContext.FromId(id);
IntPtr threadHandle = (ctx == null ? IntPtr.Zero : ctx.GetHandle());
if (threadHandle != IntPtr.Zero) {
int exitCode = 0;
SafeNativeMethods.GetExitCodeThread(new HandleRef(null, threadHandle), out exitCode);
if (!AppDomain.CurrentDomain.IsFinalizingForUnload() && exitCode == NativeMethods.STATUS_PENDING) {
IntPtr result;
if (UnsafeNativeMethods.SendMessageTimeout(new HandleRef(null, handle),
NativeMethods.WM_UIUNSUBCLASS, IntPtr.Zero, IntPtr.Zero,
UnsafeNativeMethods.SMTO_ABORTIFHUNG, 100, out result) == IntPtr.Zero) {
//Debug.Fail("unable to ping HWND:" + handle.ToString() + " during finalization");
}
}
}
}
if (handle != IntPtr.Zero) {
//if the dest thread is gone, it should be safe to unsubclass here.
ReleaseHandle(true);
}
}
if (h != IntPtr.Zero && ownedHandle) {
// If we owned the handle, post a
// WM_CLOSE to get rid of it.
//
UnsafeNativeMethods.PostMessage(new HandleRef(this, h), NativeMethods.WM_CLOSE, 0, 0);
}
}
///
/// Indicates whether a window handle was created & is being tracked.
///
internal static bool AnyHandleCreated {
get {
return anyHandleCreated;
}
}
///
///
/// Gets the handle for this window.
///
///
public IntPtr Handle {
get {
#if DEBUG
Debug.Assert(handle == IntPtr.Zero || (handleCreatedIn != null && handleCreatedIn == AppDomain.CurrentDomain),
"Attempt to access a handle created in a different domain");
// We cannot assert this here. Consider the case where someone has created an HWND on a thread but
// never started a message pump. When the thread is cleaned up by the OS USER will destroy all window
// handles. This happens long before we finalize, so when finalization does come along and we
// try to check to see if we should PostMessage(WM_CLOSE, this assert would fire.
//
// Debug.Assert(handle == IntPtr.Zero || UnsafeNativeMethods.IsWindow(new HandleRef(this, handle)),
// "Attempt to access a non-valid handle ");
#endif
return handle;
}
}
///
/// This returns the previous NativeWindow in the chain of subclasses.
/// Generally it returns null, but if someone has subclassed a control
/// through the use of a NativeWindow class, this will return the
/// previous NativeWindow subclass.
///
/// This should be public, but it is way too late for that.
///
internal NativeWindow PreviousWindow {
[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
get {
return previousWindow;
}
}
///
/// Helper method that returns a static value for the
/// unmanaged DefWindowProc call.
///
internal static IntPtr UserDefindowProc {
get {
return userDefWindowProc;
}
}
private static int WndProcFlags {
get {
// upcast for easy bit masking...
//
int intWndProcFlags = wndProcFlags;
// Check to see if a debugger is installed. If there is, then use
// DebuggableCallback instead; this callback has no try/catch around it
// so exceptions go to the debugger.
//
if (intWndProcFlags == 0) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Init wndProcFlags");
Debug.Indent();
if (userSetProcFlags != 0) {
intWndProcFlags = userSetProcFlags;
}
else if (userSetProcFlagsForApp != 0) {
intWndProcFlags = userSetProcFlagsForApp;
}
else if (!Application.CustomThreadExceptionHandlerAttached) {
if (Debugger.IsAttached) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Debugger is attached, using debuggable WndProc");
intWndProcFlags |= UseDebuggableWndProc;
}
else {
intWndProcFlags = AdjustWndProcFlagsFromRegistry(intWndProcFlags);
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "After reg check 0x" + intWndProcFlags.ToString("X", CultureInfo.InvariantCulture));
if ((intWndProcFlags & DebuggerPresent) != 0) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Debugger present");
intWndProcFlags = AdjustWndProcFlagsFromMetadata(intWndProcFlags);
if ((intWndProcFlags & AssemblyIsDebuggable) != 0) {
if ((intWndProcFlags & LoadConfigSettings) != 0) {
intWndProcFlags = AdjustWndProcFlagsFromConfig(intWndProcFlags);
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "After config check 0x" + intWndProcFlags.ToString("X", CultureInfo.InvariantCulture));
}
else {
intWndProcFlags |= UseDebuggableWndProc;
}
}
}
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "After config & debugger check 0x" + intWndProcFlags.ToString("X", CultureInfo.InvariantCulture));
}
}
#if DEBUG
if (AlwaysUseNormalWndProc.Enabled) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Stripping debuggablewndproc due to AlwaysUseNormalWndProc switch");
intWndProcFlags &= ~UseDebuggableWndProc;
}
#endif
intWndProcFlags |= InitializedFlags;
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Final 0x" + intWndProcFlags.ToString("X", CultureInfo.InvariantCulture));
wndProcFlags = (byte)intWndProcFlags;
Debug.Unindent();
}
return intWndProcFlags;
}
}
internal static bool WndProcShouldBeDebuggable {
[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
get {
return (WndProcFlags & UseDebuggableWndProc) != 0;
}
}
///
/// Inserts an entry into this hashtable.
///
private static void AddWindowToTable(IntPtr handle, NativeWindow window) {
Debug.Assert(handle != IntPtr.Zero, "Should never insert a zero handle into the hash");
lock (internalSyncObject) {
if (handleCount >= hashLoadSize) {
ExpandTable();
}
// set a flag that this thread is tracking an HWND
//
anyHandleCreated = true;
// ...same for the application
anyHandleCreatedInApp = true;
uint seed;
uint incr;
// Assume we only have one thread writing concurrently. Modify
// buckets to contain new data, as long as we insert in the right order.
uint hashcode = InitHash(handle, hashBuckets.Length, out seed, out incr);
int ntry = 0;
int emptySlotNumber = -1; // We use the empty slot number to cache the first empty slot. We chose to reuse slots
// create by remove that have the collision bit set over using up new slots.
GCHandle root = GCHandle.Alloc(window, GCHandleType.Weak);
do {
int bucketNumber = (int)(seed % (uint)hashBuckets.Length);
if (emptySlotNumber == -1 && (hashBuckets[bucketNumber].handle == new IntPtr(-1)) && (hashBuckets[bucketNumber].hash_coll < 0))
emptySlotNumber = bucketNumber;
//We need to check if the collision bit is set because we have the possibility where the first
//item in the hash-chain has been deleted.
if ((hashBuckets[bucketNumber].handle == IntPtr.Zero) ||
(hashBuckets[bucketNumber].handle == new IntPtr(-1) && ((hashBuckets[bucketNumber].hash_coll & unchecked(0x80000000)) == 0))) {
if (emptySlotNumber != -1) { // Reuse slot
bucketNumber = emptySlotNumber;
}
// Always set the hash_coll last because there may be readers
// reading the table right now on other threads.
hashBuckets[bucketNumber].window = root;
hashBuckets[bucketNumber].handle = handle;
#if DEBUG
hashBuckets[bucketNumber].owner = window.ToString();
#endif
hashBuckets[bucketNumber].hash_coll |= (int)hashcode;
handleCount++;
return;
}
// If there is an existing window in this slot, reuse it. Be sure to hook up the previous and next
// window pointers so we can get back to the right window.
//
if (((hashBuckets[bucketNumber].hash_coll & 0x7FFFFFFF) == hashcode) && handle == hashBuckets[bucketNumber].handle) {
GCHandle prevWindow = hashBuckets[bucketNumber].window;
if (prevWindow.IsAllocated) {
window.previousWindow = ((NativeWindow)prevWindow.Target);
Debug.Assert(window.previousWindow.nextWindow == null, "Last window in chain should have null next ptr");
window.previousWindow.nextWindow = window;
prevWindow.Free();
}
hashBuckets[bucketNumber].window = root;
#if DEBUG
string ownerString = string.Empty;
NativeWindow w = window;
while(w != null) {
ownerString += ("->" + w.ToString());
w = w.previousWindow;
}
hashBuckets[bucketNumber].owner = ownerString;
#endif
return;
}
if (emptySlotNumber == -1) {// We don't need to set the collision bit here since we already have an empty slot
hashBuckets[bucketNumber].hash_coll |= unchecked((int)0x80000000);
}
seed += incr;
} while (++ntry < hashBuckets.Length);
if (emptySlotNumber != -1) {
// Always set the hash_coll last because there may be readers
// reading the table right now on other threads.
hashBuckets[emptySlotNumber].window = root;
hashBuckets[emptySlotNumber].handle = handle;
#if DEBUG
hashBuckets[emptySlotNumber].owner = window.ToString();
#endif
hashBuckets[emptySlotNumber].hash_coll |= (int)hashcode;
handleCount++;
return;
}
}
// If you see this assert, make sure load factor & count are reasonable.
// Then verify that our double hash function (h2, described at top of file)
// meets the requirements described above. You should never see this assert.
Debug.Fail("native window hash table insert failed! Load factor too high, or our double hashing function is incorrect.");
}
///
/// Inserts an entry into this ID hashtable.
///
internal static void AddWindowToIDTable(object wrapper, IntPtr handle) {
NativeWindow.hashForIdHandle[NativeWindow.globalID] = handle;
NativeWindow.hashForHandleId[handle] = NativeWindow.globalID;
UnsafeNativeMethods.SetWindowLong(new HandleRef(wrapper, handle), NativeMethods.GWL_ID, new HandleRef(wrapper, (IntPtr)globalID));
globalID++;
}
// disable inlining optimization - VSW 454165
// This method introduces a dependency on System.Configuration.dll
// due to its usage of the type WindowsFormsSection
//
[MethodImplAttribute(MethodImplOptions.NoInlining)]
private static int AdjustWndProcFlagsFromConfig(int wndProcFlags) {
if (WindowsFormsSection.GetSection().JitDebugging) {
wndProcFlags |= UseDebuggableWndProc;
}
return wndProcFlags;
}
private static int AdjustWndProcFlagsFromRegistry(int wndProcFlags) {
// This is the enum used to define the meaning of the debug flag...
//
/*
//
// We split the value of DbgJITDebugLaunchSetting between the value for whether or not to ask the user and between a
// mask of places to ask. The places to ask are specified in the UnhandledExceptionLocation enum in excep.h.
//
enum DebuggerLaunchSetting
{
DLS_ASK_USER = 0x00000000,
DLS_TERMINATE_APP = 0x00000001,
DLS_ATTACH_DEBUGGER = 0x00000002,
DLS_QUESTION_MASK = 0x0000000F,
DLS_ASK_WHEN_SERVICE = 0x00000010,
DLS_MODIFIER_MASK = 0x000000F0,
DLS_LOCATION_MASK = 0xFFFFFF00,
DLS_LOCATION_SHIFT = 8 // Shift right 8 bits to get a UnhandledExceptionLocation value from the location part.
};
*/
new RegistryPermission(PermissionState.Unrestricted).Assert();
try {
Debug.Assert(wndProcFlags == 0x00, "Re-entrancy into IsDebuggerInstalled()");
RegistryKey debugKey = Registry.LocalMachine.OpenSubKey(@"Software\Microsoft\.NETFramework");
if (debugKey == null) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, ".NETFramework key not found");
return wndProcFlags;
}
try {
object value = debugKey.GetValue("DbgJITDebugLaunchSetting");
if (value != null) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "DbgJITDebugLaunchSetting value found, debugger is installed");
int dbgJit = 0;
try {
dbgJit = (int)value;
}
catch (InvalidCastException) {
// If the value isn't a DWORD, then we will
// continue to use the non-debuggable wndproc
//
dbgJit = 1;
}
// From the enum above, 0x01 == "Terminate App"... for
// anything else, we should flag that the debugger
// will catch unhandled exceptions
//
if (dbgJit != 1) {
wndProcFlags |= DebuggerPresent;
wndProcFlags |= LoadConfigSettings;
}
}
else if (debugKey.GetValue("DbgManagedDebugger") != null) {
//if there is a debugger installed, check the config files to decide
//whether to allow JIT debugging.
wndProcFlags |= DebuggerPresent;
wndProcFlags |= LoadConfigSettings;
}
}
finally {
debugKey.Close();
}
}
finally {
System.Security.CodeAccessPermission.RevertAssert();
}
return wndProcFlags;
}
static int AdjustWndProcFlagsFromMetadata(int wndProcFlags) {
if ((wndProcFlags & DebuggerPresent) != 0) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Debugger present, checking for debuggable entry assembly");
Assembly entry = Assembly.GetEntryAssembly();
if (entry != null) {
if (Attribute.IsDefined(entry, typeof(DebuggableAttribute))) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Debuggable attribute on assembly");
Attribute[] attr = Attribute.GetCustomAttributes(entry, typeof(DebuggableAttribute));
if (attr.Length > 0) {
DebuggableAttribute dbg = (DebuggableAttribute)attr[0];
if (dbg.IsJITTrackingEnabled) {
// Only if the assembly is really setup for debugging
// does it really make sense to enable the jitDebugging
//
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Entry assembly is debuggable");
wndProcFlags |= AssemblyIsDebuggable;
}
}
}
}
}
return wndProcFlags;
}
///
///
/// Assigns a handle to this
/// window.
///
///
public void AssignHandle(IntPtr handle) {
AssignHandle(handle, true);
}
//
internal void AssignHandle(IntPtr handle, bool assignUniqueID) {
//
lock (this) {
CheckReleased();
Debug.Assert(handle != IntPtr.Zero, "handle is 0");
#if DEBUG
handleCreatedIn = AppDomain.CurrentDomain;
#endif
this.handle = handle;
if (userDefWindowProc == IntPtr.Zero) {
string defproc = (Marshal.SystemDefaultCharSize == 1 ? "DefWindowProcA" : "DefWindowProcW");
userDefWindowProc = UnsafeNativeMethods.GetProcAddress(new HandleRef(null, UnsafeNativeMethods.GetModuleHandle("user32.dll")), defproc);
if (userDefWindowProc == IntPtr.Zero) {
throw new Win32Exception();
}
}
defWindowProc = UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_WNDPROC);
Debug.Assert(defWindowProc != IntPtr.Zero, "defWindowProc is 0");
if (WndProcShouldBeDebuggable) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Using debuggable wndproc");
windowProc = new NativeMethods.WndProc(this.DebuggableCallback);
}
else {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Using normal wndproc");
windowProc = new NativeMethods.WndProc(this.Callback);
}
AddWindowToTable(handle, this);
UnsafeNativeMethods.SetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_WNDPROC, windowProc);
windowProcPtr = UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_WNDPROC);
Debug.Assert(defWindowProc != windowProcPtr, "Uh oh! Subclassed ourselves!!!");
if (assignUniqueID &&
(unchecked((int)((long)UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_STYLE))) & NativeMethods.WS_CHILD) != 0 &&
unchecked((int)((long)UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_ID))) == 0) {
UnsafeNativeMethods.SetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_ID, new HandleRef(this, handle));
}
if (suppressedGC) {
new SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Assert();
try {
GC.ReRegisterForFinalize(this);
}
finally {
CodeAccessPermission.RevertAssert();
}
suppressedGC = false;
}
OnHandleChange();
}
}
///
/// Window message callback method. Control arrives here when a window
/// message is sent to this Window. This method packages the window message
/// in a Message object and invokes the wndProc() method. A WM_NCDESTROY
/// message automatically causes the releaseHandle() method to be called.
///
///
/// Raises an exception if the window handle is not zero.
///
///
///
/// Creates a window handle for this
/// window.
///
///
[
// The call to UnsafeNativeMethods.CreateWindowEx is actually an interop call...
System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Interoperability", "CA1404:CallGetLastErrorImmediatelyAfterPInvoke")
]
public virtual void CreateHandle(CreateParams cp) {
Debug.WriteLineIf(IntSecurity.SecurityDemand.TraceVerbose, "CreateAnyWindow Demanded");
IntSecurity.CreateAnyWindow.Demand();
if ((cp.Style & NativeMethods.WS_CHILD) != NativeMethods.WS_CHILD
|| cp.Parent == IntPtr.Zero) {
Debug.WriteLineIf(IntSecurity.SecurityDemand.TraceVerbose, "TopLevelWindow Demanded");
IntSecurity.TopLevelWindow.Demand();
}
//
lock (this) {
CheckReleased();
WindowClass windowClass = WindowClass.Create(cp.ClassName, cp.ClassStyle);
lock (createWindowSyncObject) {
// VSWhidbey 528778
// Why are we checking the handle again after calling CheckReleased()? It turns
// out the CLR will sometimes pump messages while we're waiting on the lock. If
// a message comes through (say a WM_ACTIVATE for the parent) which causes the
// handle to be created, we can try to create the handle twice for the same
// NativeWindow object. See bug for more details.
if (this.handle != IntPtr.Zero) {
return;
}
windowClass.targetWindow = this;
IntPtr modHandle = UnsafeNativeMethods.GetModuleHandle(null);
IntPtr createResult = IntPtr.Zero;
int lastWin32Error = 0;
// Win98 apparently doesn't believe in returning E_OUTOFMEMORY. They'd much
// rather just AV. So we catch this and then we re-throw an out of memory error.
//
try {
//(bug 109840)
//CreateWindowEx() is throwing because we're passing the WindowText arg with a string of length > 32767.
//It looks like the Windows call (CreateWindowEx) will only work
//for string lengths no greater than the max length of a 16 bit int (32767).
//We need to check the length of the string we're passing into CreateWindowEx().
//If it exceeds the max, we should take the substring....
if (cp.Caption != null && cp.Caption.Length > Int16.MaxValue) {
cp.Caption = cp.Caption.Substring(0, Int16.MaxValue);
}
createResult = UnsafeNativeMethods.CreateWindowEx(cp.ExStyle, windowClass.windowClassName,
cp.Caption, cp.Style, cp.X, cp.Y, cp.Width, cp.Height, new HandleRef(cp, cp.Parent), NativeMethods.NullHandleRef,
new HandleRef(null, modHandle), cp.Param);
lastWin32Error = Marshal.GetLastWin32Error();
}
catch (NullReferenceException e) {
throw new OutOfMemoryException(SR.GetString(SR.ErrorCreatingHandle), e);
}
windowClass.targetWindow = null;
Debug.WriteLineIf(CoreSwitches.PerfTrack.Enabled, "Handle created of type '" + cp.ClassName + "' with caption '" + cp.Caption + "' from NativeWindow of type '" + GetType().FullName + "'");
if (createResult == IntPtr.Zero) {
throw new Win32Exception(lastWin32Error, SR.GetString(SR.ErrorCreatingHandle));
}
ownHandle = true;
System.Internal.HandleCollector.Add(createResult, NativeMethods.CommonHandles.Window);
}
}
}
///
/// Window message callback method. Control arrives here when a window
/// message is sent to this Window. This method packages the window message
/// in a Message object and invokes the wndProc() method. A WM_NCDESTROY
/// message automatically causes the releaseHandle() method to be called.
///
///
/// Invokes the default window procedure associated with this Window. It is
/// an error to call this method when the Handle property is zero.
///
public void DefWndProc(ref Message m) {
if (previousWindow == null) {
if (defWindowProc == IntPtr.Zero) {
#if DEBUG
Debug.Fail("Can't find a default window procedure for message " + m.ToString() + " on class " + GetType().Name + " subclass status: " + subclassStatus);
#endif
// At this point, there isn't much we can do. There's a
// small chance the following line will allow the rest of
// the program to run, but don't get your hopes up.
m.Result = UnsafeNativeMethods.DefWindowProc(m.HWnd, m.Msg, m.WParam, m.LParam);
return;
}
m.Result = UnsafeNativeMethods.CallWindowProc(defWindowProc, m.HWnd, m.Msg, m.WParam, m.LParam);
}
else {
Debug.Assert(previousWindow != this, "Looping in our linked list");
m.Result = previousWindow.Callback(m.HWnd, m.Msg, m.WParam, m.LParam);
}
}
///
///
/// Destroys the
/// handle associated with this window.
///
///
public virtual void DestroyHandle() {
//
lock (this) {
if (handle != IntPtr.Zero) {
if (!UnsafeNativeMethods.DestroyWindow(new HandleRef(this, handle))) {
UnSubclass();
//then post a close and let it do whatever it needs to do on its own.
UnsafeNativeMethods.PostMessage(new HandleRef(this, handle), NativeMethods.WM_CLOSE, 0, 0);
}
handle = IntPtr.Zero;
ownHandle = false;
}
// Now that we have disposed, there is no need to finalize us any more. So
// Mark to the garbage collector that we no longer need finalization.
//
new SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Assert();
try {
GC.SuppressFinalize(this);
}
finally {
CodeAccessPermission.RevertAssert();
}
suppressedGC = true;
}
}
///
/// Increases the bucket count of this hashtable. This method is called from
/// the Insert method when the actual load factor of the hashtable reaches
/// the upper limit specified when the hashtable was constructed. The number
/// of buckets in the hashtable is increased to the smallest prime number
/// that is larger than twice the current number of buckets, and the entries
/// in the hashtable are redistributed into the new buckets using the cached
/// hashcodes.
///
private static void ExpandTable() {
// Allocate new Array
int oldhashsize = hashBuckets.Length;
int hashsize = GetPrime(1 + oldhashsize * 2);
// Don't replace any internal state until we've finished adding to the
// new bucket[]. This serves two purposes: 1) Allow concurrent readers
// to see valid hashtable contents at all times and 2) Protect against
// an OutOfMemoryException while allocating this new bucket[].
HandleBucket[] newBuckets = new HandleBucket[hashsize];
// rehash table into new buckets
int nb;
for (nb = 0; nb < oldhashsize; nb++) {
HandleBucket oldb = hashBuckets[nb];
if ((oldb.handle != IntPtr.Zero) && (oldb.handle != new IntPtr(-1))) {
// Now re-fit this entry into the table
//
uint seed = (uint)oldb.hash_coll & 0x7FFFFFFF;
uint incr = (uint)(1 + (((seed >> 5) + 1) % ((uint)newBuckets.Length - 1)));
do {
int bucketNumber = (int)(seed % (uint)newBuckets.Length);
if ((newBuckets[bucketNumber].handle == IntPtr.Zero) || (newBuckets[bucketNumber].handle == new IntPtr(-1))) {
newBuckets[bucketNumber].window = oldb.window;
newBuckets[bucketNumber].handle = oldb.handle;
newBuckets[bucketNumber].hash_coll |= oldb.hash_coll & 0x7FFFFFFF;
break;
}
newBuckets[bucketNumber].hash_coll |= unchecked((int)0x80000000);
seed += incr;
} while (true);
}
}
// New bucket[] is good to go - replace buckets and other internal state.
hashBuckets = newBuckets;
hashLoadSize = (int)(hashLoadFactor * hashsize);
if (hashLoadSize >= hashsize) {
hashLoadSize = hashsize - 1;
}
}
///
///
/// Retrieves the window associated with the specified
///
///
[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
public static NativeWindow FromHandle(IntPtr handle) {
if (handle != IntPtr.Zero && handleCount > 0) {
return GetWindowFromTable(handle);
}
return null;
}
///
/// Calculates a prime number of at least minSize using a static table, and
/// if we overflow it, we calculate directly.
///
private static int GetPrime(int minSize) {
if (minSize < 0) {
Debug.Fail("NativeWindow hashtable capacity overflow");
throw new OutOfMemoryException();
}
for (int i = 0; i < primes.Length; i++) {
int size = primes[i];
if (size >= minSize) return size;
}
//outside of our predefined table.
//compute the hard way.
for (int j = ((minSize - 2) | 1); j < Int32.MaxValue; j += 2) {
bool prime = true;
if ((j & 1) != 0) {
int target = (int)Math.Sqrt(j);
for (int divisor = 3; divisor < target; divisor += 2) {
if ((j % divisor) == 0) {
prime = false;
break;
}
}
if (prime) return j;
}
else {
if (j == 2) {
return j;
}
}
}
return minSize;
}
///
/// Returns the native window for the given handle, or null if
/// the handle is not in our hash table.
///
private static NativeWindow GetWindowFromTable(IntPtr handle) {
Debug.Assert(handle != IntPtr.Zero, "Zero handles cannot be stored in the table");
// Take a snapshot of buckets, in case another thread does a resize
HandleBucket[] buckets = hashBuckets;
uint seed;
uint incr;
int ntry = 0;
uint hashcode = InitHash(handle, buckets.Length, out seed, out incr);
HandleBucket b;
do {
int bucketNumber = (int)(seed % (uint)buckets.Length);
b = buckets[bucketNumber];
if (b.handle == IntPtr.Zero) {
return null;
}
if (((b.hash_coll & 0x7FFFFFFF) == hashcode) && handle == b.handle) {
if (b.window.IsAllocated) {
return (NativeWindow)b.window.Target;
}
}
seed += incr;
}
while (b.hash_coll < 0 && ++ntry < buckets.Length);
return null;
}
internal IntPtr GetHandleFromID(short id) {
IntPtr handle;
if (NativeWindow.hashForIdHandle == null || !NativeWindow.hashForIdHandle.TryGetValue(id, out handle)) {
handle = IntPtr.Zero;
}
return handle;
}
///
/// Computes the hash function: H(key, i) = h1(key) + i*h2(key, hashSize).
/// The out parameter 'seed' is h1(key), while the out parameter
/// 'incr' is h2(key, hashSize). Callers of this function should
/// add 'incr' each time through a loop.
///
private static uint InitHash(IntPtr handle, int hashsize, out uint seed, out uint incr) {
// Hashcode must be positive. Also, we must not use the sign bit, since
// that is used for the collision bit.
uint hashcode = ((uint)handle.GetHashCode()) & 0x7FFFFFFF;
seed = (uint)hashcode;
// Restriction: incr MUST be between 1 and hashsize - 1, inclusive for
// the modular arithmetic to work correctly. This guarantees you'll
// visit every bucket in the table exactly once within hashsize
// iterations. Violate this and it'll cause obscure bugs forever.
// If you change this calculation for h2(key), update putEntry too!
incr = (uint)(1 + (((seed >> 5) + 1) % ((uint)hashsize - 1)));
return hashcode;
}
///
///
/// Specifies a notification method that is called when the handle for a
/// window is changed.
///
///
protected virtual void OnHandleChange() {
}
///
/// On class load, we connect an event to Application to let us know when
/// the process or domain terminates. When this happens, we attempt to
/// clear our window class cache. We cannot destroy windows (because we don't
/// have access to their thread), and we cannot unregister window classes
/// (because the classes are in use by the windows we can't destroy). Instead,
/// we move the class and window procs to DefWndProc
///
[PrePrepareMethod]
private static void OnShutdown(object sender, EventArgs e) {
// If we still have windows allocated, we must sling them to userDefWindowProc
// or else they will AV if they get a message after the managed code has been
// removed. In debug builds, we assert and give the "ToString" of the native
// window. In retail we just detatch the window proc and let it go. Note that
// we cannot call DestroyWindow because this API will fail if called from
// an incorrect thread.
//
if (handleCount > 0) {
Debug.Assert(userDefWindowProc != IntPtr.Zero, "We have active windows but no user window proc?");
lock (internalSyncObject) {
for (int i = 0; i < hashBuckets.Length; i++) {
HandleBucket b = hashBuckets[i];
if (b.handle != IntPtr.Zero && b.handle != new IntPtr(-1)) {
HandleRef href = new HandleRef(b, b.handle);
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, new HandleRef(null, userDefWindowProc));
UnsafeNativeMethods.SetClassLong(href, NativeMethods.GCL_WNDPROC, userDefWindowProc);
UnsafeNativeMethods.PostMessage(href, NativeMethods.WM_CLOSE, 0, 0);
// Fish out the Window object, if it is valid, and NULL the handle pointer. This
// way the rest of winforms won't think the handle is still valid here.
if (b.window.IsAllocated) {
NativeWindow w = (NativeWindow)b.window.Target;
if (w != null) {
w.handle = IntPtr.Zero;
}
}
#if DEBUG && FINALIZATION_WATCH
Debug.Fail("Window did not clean itself up: " + b.owner);
#endif
b.window.Free();
}
hashBuckets[i].handle = IntPtr.Zero;
hashBuckets[i].hash_coll = 0;
}
handleCount = 0;
}
}
WindowClass.DisposeCache();
}
///
///
/// When overridden in a derived class,
/// manages an unhandled thread
/// exception.
///
///
protected virtual void OnThreadException(Exception e) {
}
///
///
/// Releases the handle associated with this window.
///
///
public virtual void ReleaseHandle() {
ReleaseHandle(true);
}
///
/// Releases the handle associated with this window. If handleValid
/// is true, this will unsubclass the window as well. HandleValid
/// should be false if we are releasing in response to a
/// WM_DESTROY. Unsubclassing during this message can cause problems
/// with XP's theme manager and it's not needed anyway.
///
private void ReleaseHandle(bool handleValid) {
if (handle != IntPtr.Zero) {
//
lock (this) {
if (handle != IntPtr.Zero) {
if (handleValid) {
UnSubclass();
}
RemoveWindowFromTable(handle, this);
if (ownHandle) {
System.Internal.HandleCollector.Remove(handle, NativeMethods.CommonHandles.Window);
ownHandle = false;
}
handle = IntPtr.Zero;
//if not finalizing already.
if (weakThisPtr.IsAlive && weakThisPtr.Target != null) {
OnHandleChange();
// Now that we have disposed, there is no need to finalize us any more. So
// Mark to the garbage collector that we no longer need finalization.
//
new SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Assert();
try {
GC.SuppressFinalize(this);
}
finally {
CodeAccessPermission.RevertAssert();
}
suppressedGC = true;
}
}
}
}
}
///
/// Removes an entry from this hashtable. If an entry with the specified
/// key exists in the hashtable, it is removed.
///
private static void RemoveWindowFromTable(IntPtr handle, NativeWindow window) {
Debug.Assert(handle != IntPtr.Zero, "Incorrect handle");
lock (internalSyncObject) {
uint seed;
uint incr;
// Assuming only one concurrent writer, write directly into buckets.
uint hashcode = InitHash(handle, hashBuckets.Length, out seed, out incr);
int ntry = 0;
NativeWindow prevWindow = window.PreviousWindow;
HandleBucket b;
int bn; // bucketNumber
do {
bn = (int)(seed % (uint)hashBuckets.Length); // bucketNumber
b = hashBuckets[bn];
if (((b.hash_coll & 0x7FFFFFFF) == hashcode) && handle == b.handle) {
bool should----Bucket = (window.nextWindow == null);
bool shouldReplaceBucket = IsRootWindowInListWithChildren(window);
// We need to fixup the link pointers of window here.
//
if (window.previousWindow != null) {
window.previousWindow.nextWindow = window.nextWindow;
}
if (window.nextWindow != null) {
window.nextWindow.defWindowProc = window.defWindowProc;
window.nextWindow.previousWindow = window.previousWindow;
}
window.nextWindow = null;
window.previousWindow = null;
if (shouldReplaceBucket) {
// Free the existing GC handle
if (hashBuckets[bn].window.IsAllocated) {
hashBuckets[bn].window.Free();
}
hashBuckets[bn].window = GCHandle.Alloc(prevWindow, GCHandleType.Weak);
}
else if (should----Bucket) {
// Clear hash_coll field, then key, then value
hashBuckets[bn].hash_coll &= unchecked((int)0x80000000);
if (hashBuckets[bn].hash_coll != 0) {
hashBuckets[bn].handle = new IntPtr(-1);
}
else {
hashBuckets[bn].handle = IntPtr.Zero;
}
if (hashBuckets[bn].window.IsAllocated) {
hashBuckets[bn].window.Free();
}
Debug.Assert(handleCount > 0, "Underflow on handle count");
handleCount--;
}
return;
}
seed += incr;
} while (hashBuckets[bn].hash_coll < 0 && ++ntry < hashBuckets.Length);
}
}
///
/// Determines if the given window is the first member of the linked list
///
private static bool IsRootWindowInListWithChildren(NativeWindow window) {
// This seems backwards, but it isn't. When a new subclass comes in,
// it's previousWindow field is set to the previous subclass. Therefore,
// the top of the subclass chain has nextWindow == null and previousWindow
// == the first child subclass.
return ((window.PreviousWindow != null) && (window.nextWindow == null));
}
///
/// Determines if the given window is the first member of the linked list
/// and has no children
///
/* No one is calling this private method, so it is safe to comment it out.
private static bool IsRootWindowInListWithNoChildren(NativeWindow window)
{
return ((window.PreviousWindow == null) && (window.nextWindow == null));
}
*/
///
/// Inserts an entry into this ID hashtable.
///
internal static void RemoveWindowFromIDTable(IntPtr handle) {
short id = (short)NativeWindow.hashForHandleId[handle];
NativeWindow.hashForHandleId.Remove(handle);
NativeWindow.hashForIdHandle.Remove(id);
}
///
/// This method can be used to modify the exception handling behavior of
/// NativeWindow. By default, NativeWindow will detect if an application
/// is running under a debugger, or is running on a machine with a debugger
/// installed. In this case, an unhandled exception in the NativeWindow's
/// WndProc method will remain unhandled so the debugger can trap it. If
/// there is no debugger installed NativeWindow will trap the exception
/// and route it to the Application class's unhandled exception filter.
///
/// You can control this behavior via a config file, or directly through
/// code using this method. Setting the unhandled exception mode does
/// not change the behavior of any NativeWindow objects that are currently
/// connected to window handles; it only affects new handle connections.
///
/// When threadScope is false, the application exception mode is set. The
/// application exception mode is used for all threads that have the Automatic mode.
/// Setting the application exception mode does not affect the setting of the current thread.
///
/// When threadScope is true, the thread exception mode is set. The thread
/// exception mode overrides the application exception mode if it's not Automatic.
///
internal static void SetUnhandledExceptionModeInternal(UnhandledExceptionMode mode, bool threadScope) {
if (!threadScope && anyHandleCreatedInApp) {
throw new InvalidOperationException(SR.GetString(SR.ApplicationCannotChangeApplicationExceptionMode));
}
if (threadScope && anyHandleCreated) {
throw new InvalidOperationException(SR.GetString(SR.ApplicationCannotChangeThreadExceptionMode));
}
switch (mode) {
case UnhandledExceptionMode.Automatic:
if (threadScope) {
userSetProcFlags = 0;
}
else {
userSetProcFlagsForApp = 0;
}
break;
case UnhandledExceptionMode.ThrowException:
if (threadScope) {
userSetProcFlags = UseDebuggableWndProc | InitializedFlags;
}
else {
userSetProcFlagsForApp = UseDebuggableWndProc | InitializedFlags;
}
break;
case UnhandledExceptionMode.CatchException:
if (threadScope) {
userSetProcFlags = InitializedFlags;
}
else {
userSetProcFlagsForApp = InitializedFlags;
}
break;
default:
throw new InvalidEnumArgumentException("mode", (int)mode, typeof(UnhandledExceptionMode));
}
}
///
/// Unsubclassing is a tricky business. We need to account for
/// some border cases:
///
/// 1) User has done multiple subclasses but has un-subclassed out of order.
/// 2) User has done multiple subclasses but now our defWindowProc points to
/// a NativeWindow that has GC'd
/// 3) User releasing this handle but this NativeWindow is not the current
/// window proc.
///
private void UnSubclass() {
bool finalizing = (!weakThisPtr.IsAlive || weakThisPtr.Target == null);
HandleRef href = new HandleRef(this, handle);
// Don't touch if the current window proc is not ours.
//
IntPtr currentWinPrc = UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_WNDPROC);
if (windowProcPtr == currentWinPrc) {
if (previousWindow == null) {
#if DEBUG
subclassStatus = "Unsubclassing back to native defWindowProc";
#endif
// If the defWindowProc points to a native window proc, previousWindow will
// be null. In this case, it is completely safe to assign defWindowProc
// to the current wndproc.
//
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, new HandleRef(this, defWindowProc));
}
else {
if (finalizing) {
#if DEBUG
subclassStatus = "Setting back to userDefWindowProc -- next chain is managed";
#endif
// Here, we are finalizing and defWindowProc is pointing to a managed object. We must assume
// that the object defWindowProc is pointing to is also finalizing. Why? Because we're
// holding a ref to it, and it is holding a ref to us. The only way this cycle will
// finalize is if no one else is hanging onto it. So, we re-assign the window proc to
// userDefWindowProc.
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, new HandleRef(this, userDefWindowProc));
}
else {
#if DEBUG
subclassStatus = "Setting back to next managed subclass object";
#endif
// Here we are not finalizing so we use the windowProc for our previous window. This may
// DIFFER from the value we are currently storing in defWindowProc because someone may
// have re-subclassed.
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, previousWindow.windowProc);
}
}
}
else {
// cutting the subclass chain anyway, even if we're not the last one in the chain
// if the whole chain is all managed NativeWindow it doesnt matter,
// if the chain is not, then someone has been dirty and didn't clean up properly, too bad for them...
//We will cut off the chain if we cannot unsubclass.
//If we find previouswindow pointing to us, then we can let RemoveWindowFromTable reassign the
//defwndproc pointers properly when this guy gets removed (thereby unsubclassing ourselves)
if (nextWindow == null || nextWindow.defWindowProc != windowProcPtr) {
// we didn't find it... let's unhook anyway and cut the chain... this prevents crashes
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, new HandleRef(this, userDefWindowProc));
}
#if DEBUG
subclassStatus = "FORCE unsubclass -- we do not own the subclass";
#endif
}
}
///
///
/// Invokes the default window procedure associated with
/// this window.
///
///
protected virtual void WndProc(ref Message m) {
DefWndProc(ref m);
}
///
/// A struct that contains a single bucket for our handle / GCHandle hash table.
/// The hash table algorithm we use here was stolen selfishly from the framework's
/// Hashtable class. We don't use Hashtable directly, however, because of boxing
/// concerns. It's algorithm is perfect for our needs, however: Multiple
/// reader, single writer without the need for locks and constant lookup time.
///
/// Differences between this implementation and Hashtable:
///
/// Keys are IntPtrs; their hash code is their value. Collision is still
/// marked with the high bit.
///
/// Reclaimed buckets store -1 in their handle, not the hash table reference.
///
private struct HandleBucket {
public IntPtr handle; // Win32 window handle
public GCHandle window; // a weak GC handle to the NativeWindow class
public int hash_coll; // Store hash code; sign bit means there was a collision.
#if DEBUG
public string owner; // owner of this handle
#endif
}
///
/// WindowClass encapsulates a window class.
///
///
/// Retrieves a WindowClass object for use. This will create a new
/// object if there is no such class/style available, or retrun a
/// cached object if one exists.
///
internal static WindowClass Create(string className, int classStyle) {
lock (wcInternalSyncObject) {
WindowClass wc = cache;
if (className == null) {
while (wc != null && (wc.className != null ||
wc.classStyle != classStyle)) wc = wc.next;
}
else {
while (wc != null &&
!className.Equals(wc.className)) {
wc = wc.next;
}
}
if (wc == null) {
wc = new WindowClass(className, classStyle);
wc.next = cache;
cache = wc;
}
else {
if (!wc.registered) {
wc.RegisterClass();
}
}
return wc;
}
}
///
/// Disposes our window class cache. This doesn't free anything
/// from the actual cache; it merely attempts to unregister
/// the classes of everything in the cache. This allows the unused
/// classes to be unrooted. They can later be re-rooted and reused.
///
internal static void DisposeCache() {
lock (wcInternalSyncObject) {
WindowClass wc = cache;
while (wc != null) {
wc.UnregisterClass();
wc = wc.next;
}
}
}
///
/// Fabricates a full class name from a partial.
///
private string GetFullClassName(string className) {
StringBuilder b = new StringBuilder(50);
b.Append(Application.WindowsFormsVersion);
b.Append('.');
b.Append(className);
b.Append(".app.");
b.Append(domainQualifier);
b.Append('.');
b.Append(Convert.ToString(AppDomain.CurrentDomain.GetHashCode(), 16));
return b.ToString();
}
///
/// Once the classname and style bits have been set, this can
/// be called to register the class.
///
private void RegisterClass() {
NativeMethods.WNDCLASS_D wndclass = new NativeMethods.WNDCLASS_D();
if (userDefWindowProc == IntPtr.Zero) {
string defproc = (Marshal.SystemDefaultCharSize == 1 ? "DefWindowProcA" : "DefWindowProcW");
userDefWindowProc = UnsafeNativeMethods.GetProcAddress(new HandleRef(null, UnsafeNativeMethods.GetModuleHandle("user32.dll")), defproc);
if (userDefWindowProc == IntPtr.Zero) {
throw new Win32Exception();
}
}
string localClassName = className;
if (localClassName == null) {
// If we don't use a hollow brush here, Windows will "pre paint" us with COLOR_WINDOW which
// creates a little bit if flicker. This happens even though we are overriding wm_erasebackgnd.
// Make this hollow to avoid all flicker.
//
wndclass.hbrBackground = UnsafeNativeMethods.GetStockObject(NativeMethods.HOLLOW_BRUSH); //(IntPtr)(NativeMethods.COLOR_WINDOW + 1);
wndclass.style = classStyle;
defWindowProc = userDefWindowProc;
localClassName = "Window." + Convert.ToString(classStyle, 16);
hashCode = 0;
}
else {
NativeMethods.WNDCLASS_I wcls = new NativeMethods.WNDCLASS_I();
bool ok = UnsafeNativeMethods.GetClassInfo(NativeMethods.NullHandleRef, className, wcls);
int error = Marshal.GetLastWin32Error();
if (!ok) {
throw new Win32Exception(error, SR.GetString(SR.InvalidWndClsName));
}
wndclass.style = wcls.style;
wndclass.cbClsExtra = wcls.cbClsExtra;
wndclass.cbWndExtra = wcls.cbWndExtra;
wndclass.hIcon = wcls.hIcon;
wndclass.hCursor = wcls.hCursor;
wndclass.hbrBackground = wcls.hbrBackground;
wndclass.lpszMenuName = Marshal.PtrToStringAuto(wcls.lpszMenuName);
localClassName = className;
defWindowProc = wcls.lpfnWndProc;
hashCode = className.GetHashCode();
}
// Our static data is different for different app domains, so we include the app domain in with
// our window class name. This way our static table always matches what Win32 thinks.
//
windowClassName = GetFullClassName(localClassName);
windowProc = new NativeMethods.WndProc(this.Callback);
wndclass.lpfnWndProc = windowProc;
wndclass.hInstance = UnsafeNativeMethods.GetModuleHandle(null);
wndclass.lpszClassName = windowClassName;
short atom = UnsafeNativeMethods.RegisterClass(wndclass);
if (atom == 0) {
int err = Marshal.GetLastWin32Error();
if (err == NativeMethods.ERROR_CLASS_ALREADY_EXISTS) {
// Check to see if the window class window
// proc points to DefWndProc. If it does, then
// this is a class from a rudely-terminated app domain
// and we can safely reuse it. If not, we've got
// to throw.
NativeMethods.WNDCLASS_I wcls = new NativeMethods.WNDCLASS_I();
bool ok = UnsafeNativeMethods.GetClassInfo(new HandleRef(null, UnsafeNativeMethods.GetModuleHandle(null)), windowClassName, wcls);
if (ok && wcls.lpfnWndProc == NativeWindow.UserDefindowProc) {
// We can just reuse this class because we have marked it
// as being a nop in another domain. All we need to do is call SetClassLong.
// Only one problem: SetClassLong takes an HWND, which we don't have. That leaves
// us with some tricky business. First, try this the easy way and see
// if we can simply unregister and re-register the class. This might
// work because the other domain shutdown would have posted WM_CLOSE to all
// the windows of the class.
if (UnsafeNativeMethods.UnregisterClass(windowClassName, new HandleRef(null, UnsafeNativeMethods.GetModuleHandle(null)))) {
atom = UnsafeNativeMethods.RegisterClass(wndclass);
// If this fails, we will always raise the first err above. No sense exposing our twiddling.
}
else {
// This is a little harder. We cannot reuse the class because it is
// already in use. We must create a new class. We bump our domain qualifier
// here to account for this, so we only do this expensive search once for the
// domain.
do {
domainQualifier++;
windowClassName = GetFullClassName(localClassName);
wndclass.lpszClassName = windowClassName;
atom = UnsafeNativeMethods.RegisterClass(wndclass);
} while (atom == 0 && Marshal.GetLastWin32Error() == NativeMethods.ERROR_CLASS_ALREADY_EXISTS);
}
}
}
if (atom == 0) {
windowProc = null;
throw new Win32Exception(err);
}
}
registered = true;
}
///
/// Unregisters this window class. Unregistration is not a
/// last resort; the window class may be re-registered through
/// a call to registerClass.
///
private void UnregisterClass() {
if (registered && UnsafeNativeMethods.UnregisterClass(windowClassName, new HandleRef(null, UnsafeNativeMethods.GetModuleHandle(null)))) {
windowProc = null;
registered = false;
}
}
}
}
///
/// Determines the exception mode of NativeWindow's WndProc method. Pass
/// a value of this enum into SetUnhandledExceptionMode to control how
/// new NativeWindow objects handle exceptions.
///
public enum UnhandledExceptionMode {
Automatic,
ThrowException,
CatchException
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//-----------------------------------------------------------------------------
/*
*/
namespace System.Windows.Forms {
using System.Threading;
using System.Configuration.Assemblies;
using System.Runtime.Remoting;
using System.Runtime.InteropServices;
using System.Runtime.ConstrainedExecution;
using System.Runtime.CompilerServices;
using System.Reflection;
using System.Security;
using System.Security.Permissions;
using System.Diagnostics;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using System.ComponentModel;
using Microsoft.Win32;
using System.Text;
using System.Globalization;
using System.Diagnostics.CodeAnalysis;
///
///
/// Provides a low-level encapsulation of a window handle
/// and a window procedure. The class automatically manages window class creation and registration.
///
///
[
SecurityPermission(SecurityAction.InheritanceDemand, Flags = SecurityPermissionFlag.UnmanagedCode),
SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)
]
public class NativeWindow : MarshalByRefObject, IWin32Window {
#if DEBUG
private static readonly BooleanSwitch AlwaysUseNormalWndProc = new BooleanSwitch("AlwaysUseNormalWndProc", "Skips checking for the debugger when choosing the debuggable WndProc handler");
private static readonly TraceSwitch WndProcChoice = new TraceSwitch("WndProcChoice", "Info about choice of WndProc");
#else
private static readonly TraceSwitch WndProcChoice;
#endif
/**
* Table of prime numbers to use as hash table sizes. Each entry is the
* smallest prime number larger than twice the previous entry.
*/
private readonly static int[] primes = {
11,17,23,29,37,47,59,71,89,107,131,163,197,239,293,353,431,521,631,761,919,
1103,1327,1597,1931,2333,2801,3371,4049,4861,5839,7013,8419,10103,12143,14591,
17519,21023,25229,30293,36353,43627,52361,62851,75431,90523, 108631, 130363,
156437, 187751, 225307, 270371, 324449, 389357, 467237, 560689, 672827, 807403,
968897, 1162687, 1395263, 1674319, 2009191, 2411033, 2893249, 3471899, 4166287,
4999559, 5999471, 7199369
};
const int InitializedFlags = 0x01;
const int DebuggerPresent = 0x02;
const int UseDebuggableWndProc = 0x04;
const int LoadConfigSettings = 0x08;
const int AssemblyIsDebuggable = 0x10;
// do we have any active HWNDs?
//
[ThreadStatic]
static bool anyHandleCreated;
static bool anyHandleCreatedInApp;
const float hashLoadFactor = .72F;
private static int handleCount;
private static int hashLoadSize;
private static HandleBucket[] hashBuckets;
private static IntPtr userDefWindowProc;
[ThreadStatic]
private static byte wndProcFlags = 0;
[ThreadStatic]
private static byte userSetProcFlags = 0;
private static byte userSetProcFlagsForApp;
//nned to Store Table of Ids and Handles
private static short globalID = 1;
private static Dictionary hashForIdHandle;
private static Dictionary hashForHandleId;
private static object internalSyncObject = new object();
private static object createWindowSyncObject = new object();
#if DEBUG
AppDomain handleCreatedIn = null;
string subclassStatus = "None";
#endif
IntPtr handle;
NativeMethods.WndProc windowProc;
IntPtr windowProcPtr;
IntPtr defWindowProc;
bool suppressedGC;
bool ownHandle;
NativeWindow previousWindow; // doubly linked list of subclasses.
NativeWindow nextWindow;
WeakReference weakThisPtr;
static NativeWindow() {
EventHandler shutdownHandler = new EventHandler(OnShutdown);
AppDomain.CurrentDomain.ProcessExit += shutdownHandler;
AppDomain.CurrentDomain.DomainUnload += shutdownHandler;
// Initialize our static hash of handles. I have chosen
// a prime bucket based on a typical number of window handles
// needed to start up a decent sized app.
int hashSize = primes[4];
hashBuckets = new HandleBucket[hashSize];
hashLoadSize = (int)(hashLoadFactor * hashSize);
if (hashLoadSize >= hashSize) {
hashLoadSize = hashSize - 1;
}
//Intilialize the Hashtable for Id...
hashForIdHandle = new Dictionary();
hashForHandleId = new Dictionary();
}
public NativeWindow() {
weakThisPtr = new WeakReference(this);
}
///
/// Override's the base object's finalize method.
///
~NativeWindow() {
ForceExitMessageLoop();
}
///
/// This was factored into another function so the finalizer in control that releases the window
/// can perform the exact same code without further changes. If you make changes to the finalizer,
/// change this method -- try not to change NativeWindow's finalizer.
///
internal void ForceExitMessageLoop() {
IntPtr h;
bool ownedHandle;
//
lock (this) {
h = handle;
ownedHandle = ownHandle;
}
if (handle != IntPtr.Zero) {
//now, before we set handle to zero and finish the finalizer, let's send
// a WM_NULL to the window. Why? Because if the main ui thread is INSIDE
// the wndproc for this control during our unsubclass, then we could AV
// when control finally reaches us.
if (UnsafeNativeMethods.IsWindow(new HandleRef(null, handle))) {
int lpdwProcessId; //unused
int id = SafeNativeMethods.GetWindowThreadProcessId(new HandleRef(null, handle), out lpdwProcessId);
Application.ThreadContext ctx = Application.ThreadContext.FromId(id);
IntPtr threadHandle = (ctx == null ? IntPtr.Zero : ctx.GetHandle());
if (threadHandle != IntPtr.Zero) {
int exitCode = 0;
SafeNativeMethods.GetExitCodeThread(new HandleRef(null, threadHandle), out exitCode);
if (!AppDomain.CurrentDomain.IsFinalizingForUnload() && exitCode == NativeMethods.STATUS_PENDING) {
IntPtr result;
if (UnsafeNativeMethods.SendMessageTimeout(new HandleRef(null, handle),
NativeMethods.WM_UIUNSUBCLASS, IntPtr.Zero, IntPtr.Zero,
UnsafeNativeMethods.SMTO_ABORTIFHUNG, 100, out result) == IntPtr.Zero) {
//Debug.Fail("unable to ping HWND:" + handle.ToString() + " during finalization");
}
}
}
}
if (handle != IntPtr.Zero) {
//if the dest thread is gone, it should be safe to unsubclass here.
ReleaseHandle(true);
}
}
if (h != IntPtr.Zero && ownedHandle) {
// If we owned the handle, post a
// WM_CLOSE to get rid of it.
//
UnsafeNativeMethods.PostMessage(new HandleRef(this, h), NativeMethods.WM_CLOSE, 0, 0);
}
}
///
/// Indicates whether a window handle was created & is being tracked.
///
internal static bool AnyHandleCreated {
get {
return anyHandleCreated;
}
}
///
///
/// Gets the handle for this window.
///
///
public IntPtr Handle {
get {
#if DEBUG
Debug.Assert(handle == IntPtr.Zero || (handleCreatedIn != null && handleCreatedIn == AppDomain.CurrentDomain),
"Attempt to access a handle created in a different domain");
// We cannot assert this here. Consider the case where someone has created an HWND on a thread but
// never started a message pump. When the thread is cleaned up by the OS USER will destroy all window
// handles. This happens long before we finalize, so when finalization does come along and we
// try to check to see if we should PostMessage(WM_CLOSE, this assert would fire.
//
// Debug.Assert(handle == IntPtr.Zero || UnsafeNativeMethods.IsWindow(new HandleRef(this, handle)),
// "Attempt to access a non-valid handle ");
#endif
return handle;
}
}
///
/// This returns the previous NativeWindow in the chain of subclasses.
/// Generally it returns null, but if someone has subclassed a control
/// through the use of a NativeWindow class, this will return the
/// previous NativeWindow subclass.
///
/// This should be public, but it is way too late for that.
///
internal NativeWindow PreviousWindow {
[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
get {
return previousWindow;
}
}
///
/// Helper method that returns a static value for the
/// unmanaged DefWindowProc call.
///
internal static IntPtr UserDefindowProc {
get {
return userDefWindowProc;
}
}
private static int WndProcFlags {
get {
// upcast for easy bit masking...
//
int intWndProcFlags = wndProcFlags;
// Check to see if a debugger is installed. If there is, then use
// DebuggableCallback instead; this callback has no try/catch around it
// so exceptions go to the debugger.
//
if (intWndProcFlags == 0) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Init wndProcFlags");
Debug.Indent();
if (userSetProcFlags != 0) {
intWndProcFlags = userSetProcFlags;
}
else if (userSetProcFlagsForApp != 0) {
intWndProcFlags = userSetProcFlagsForApp;
}
else if (!Application.CustomThreadExceptionHandlerAttached) {
if (Debugger.IsAttached) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Debugger is attached, using debuggable WndProc");
intWndProcFlags |= UseDebuggableWndProc;
}
else {
intWndProcFlags = AdjustWndProcFlagsFromRegistry(intWndProcFlags);
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "After reg check 0x" + intWndProcFlags.ToString("X", CultureInfo.InvariantCulture));
if ((intWndProcFlags & DebuggerPresent) != 0) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Debugger present");
intWndProcFlags = AdjustWndProcFlagsFromMetadata(intWndProcFlags);
if ((intWndProcFlags & AssemblyIsDebuggable) != 0) {
if ((intWndProcFlags & LoadConfigSettings) != 0) {
intWndProcFlags = AdjustWndProcFlagsFromConfig(intWndProcFlags);
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "After config check 0x" + intWndProcFlags.ToString("X", CultureInfo.InvariantCulture));
}
else {
intWndProcFlags |= UseDebuggableWndProc;
}
}
}
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "After config & debugger check 0x" + intWndProcFlags.ToString("X", CultureInfo.InvariantCulture));
}
}
#if DEBUG
if (AlwaysUseNormalWndProc.Enabled) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Stripping debuggablewndproc due to AlwaysUseNormalWndProc switch");
intWndProcFlags &= ~UseDebuggableWndProc;
}
#endif
intWndProcFlags |= InitializedFlags;
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Final 0x" + intWndProcFlags.ToString("X", CultureInfo.InvariantCulture));
wndProcFlags = (byte)intWndProcFlags;
Debug.Unindent();
}
return intWndProcFlags;
}
}
internal static bool WndProcShouldBeDebuggable {
[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
get {
return (WndProcFlags & UseDebuggableWndProc) != 0;
}
}
///
/// Inserts an entry into this hashtable.
///
private static void AddWindowToTable(IntPtr handle, NativeWindow window) {
Debug.Assert(handle != IntPtr.Zero, "Should never insert a zero handle into the hash");
lock (internalSyncObject) {
if (handleCount >= hashLoadSize) {
ExpandTable();
}
// set a flag that this thread is tracking an HWND
//
anyHandleCreated = true;
// ...same for the application
anyHandleCreatedInApp = true;
uint seed;
uint incr;
// Assume we only have one thread writing concurrently. Modify
// buckets to contain new data, as long as we insert in the right order.
uint hashcode = InitHash(handle, hashBuckets.Length, out seed, out incr);
int ntry = 0;
int emptySlotNumber = -1; // We use the empty slot number to cache the first empty slot. We chose to reuse slots
// create by remove that have the collision bit set over using up new slots.
GCHandle root = GCHandle.Alloc(window, GCHandleType.Weak);
do {
int bucketNumber = (int)(seed % (uint)hashBuckets.Length);
if (emptySlotNumber == -1 && (hashBuckets[bucketNumber].handle == new IntPtr(-1)) && (hashBuckets[bucketNumber].hash_coll < 0))
emptySlotNumber = bucketNumber;
//We need to check if the collision bit is set because we have the possibility where the first
//item in the hash-chain has been deleted.
if ((hashBuckets[bucketNumber].handle == IntPtr.Zero) ||
(hashBuckets[bucketNumber].handle == new IntPtr(-1) && ((hashBuckets[bucketNumber].hash_coll & unchecked(0x80000000)) == 0))) {
if (emptySlotNumber != -1) { // Reuse slot
bucketNumber = emptySlotNumber;
}
// Always set the hash_coll last because there may be readers
// reading the table right now on other threads.
hashBuckets[bucketNumber].window = root;
hashBuckets[bucketNumber].handle = handle;
#if DEBUG
hashBuckets[bucketNumber].owner = window.ToString();
#endif
hashBuckets[bucketNumber].hash_coll |= (int)hashcode;
handleCount++;
return;
}
// If there is an existing window in this slot, reuse it. Be sure to hook up the previous and next
// window pointers so we can get back to the right window.
//
if (((hashBuckets[bucketNumber].hash_coll & 0x7FFFFFFF) == hashcode) && handle == hashBuckets[bucketNumber].handle) {
GCHandle prevWindow = hashBuckets[bucketNumber].window;
if (prevWindow.IsAllocated) {
window.previousWindow = ((NativeWindow)prevWindow.Target);
Debug.Assert(window.previousWindow.nextWindow == null, "Last window in chain should have null next ptr");
window.previousWindow.nextWindow = window;
prevWindow.Free();
}
hashBuckets[bucketNumber].window = root;
#if DEBUG
string ownerString = string.Empty;
NativeWindow w = window;
while(w != null) {
ownerString += ("->" + w.ToString());
w = w.previousWindow;
}
hashBuckets[bucketNumber].owner = ownerString;
#endif
return;
}
if (emptySlotNumber == -1) {// We don't need to set the collision bit here since we already have an empty slot
hashBuckets[bucketNumber].hash_coll |= unchecked((int)0x80000000);
}
seed += incr;
} while (++ntry < hashBuckets.Length);
if (emptySlotNumber != -1) {
// Always set the hash_coll last because there may be readers
// reading the table right now on other threads.
hashBuckets[emptySlotNumber].window = root;
hashBuckets[emptySlotNumber].handle = handle;
#if DEBUG
hashBuckets[emptySlotNumber].owner = window.ToString();
#endif
hashBuckets[emptySlotNumber].hash_coll |= (int)hashcode;
handleCount++;
return;
}
}
// If you see this assert, make sure load factor & count are reasonable.
// Then verify that our double hash function (h2, described at top of file)
// meets the requirements described above. You should never see this assert.
Debug.Fail("native window hash table insert failed! Load factor too high, or our double hashing function is incorrect.");
}
///
/// Inserts an entry into this ID hashtable.
///
internal static void AddWindowToIDTable(object wrapper, IntPtr handle) {
NativeWindow.hashForIdHandle[NativeWindow.globalID] = handle;
NativeWindow.hashForHandleId[handle] = NativeWindow.globalID;
UnsafeNativeMethods.SetWindowLong(new HandleRef(wrapper, handle), NativeMethods.GWL_ID, new HandleRef(wrapper, (IntPtr)globalID));
globalID++;
}
// disable inlining optimization - VSW 454165
// This method introduces a dependency on System.Configuration.dll
// due to its usage of the type WindowsFormsSection
//
[MethodImplAttribute(MethodImplOptions.NoInlining)]
private static int AdjustWndProcFlagsFromConfig(int wndProcFlags) {
if (WindowsFormsSection.GetSection().JitDebugging) {
wndProcFlags |= UseDebuggableWndProc;
}
return wndProcFlags;
}
private static int AdjustWndProcFlagsFromRegistry(int wndProcFlags) {
// This is the enum used to define the meaning of the debug flag...
//
/*
//
// We split the value of DbgJITDebugLaunchSetting between the value for whether or not to ask the user and between a
// mask of places to ask. The places to ask are specified in the UnhandledExceptionLocation enum in excep.h.
//
enum DebuggerLaunchSetting
{
DLS_ASK_USER = 0x00000000,
DLS_TERMINATE_APP = 0x00000001,
DLS_ATTACH_DEBUGGER = 0x00000002,
DLS_QUESTION_MASK = 0x0000000F,
DLS_ASK_WHEN_SERVICE = 0x00000010,
DLS_MODIFIER_MASK = 0x000000F0,
DLS_LOCATION_MASK = 0xFFFFFF00,
DLS_LOCATION_SHIFT = 8 // Shift right 8 bits to get a UnhandledExceptionLocation value from the location part.
};
*/
new RegistryPermission(PermissionState.Unrestricted).Assert();
try {
Debug.Assert(wndProcFlags == 0x00, "Re-entrancy into IsDebuggerInstalled()");
RegistryKey debugKey = Registry.LocalMachine.OpenSubKey(@"Software\Microsoft\.NETFramework");
if (debugKey == null) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, ".NETFramework key not found");
return wndProcFlags;
}
try {
object value = debugKey.GetValue("DbgJITDebugLaunchSetting");
if (value != null) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "DbgJITDebugLaunchSetting value found, debugger is installed");
int dbgJit = 0;
try {
dbgJit = (int)value;
}
catch (InvalidCastException) {
// If the value isn't a DWORD, then we will
// continue to use the non-debuggable wndproc
//
dbgJit = 1;
}
// From the enum above, 0x01 == "Terminate App"... for
// anything else, we should flag that the debugger
// will catch unhandled exceptions
//
if (dbgJit != 1) {
wndProcFlags |= DebuggerPresent;
wndProcFlags |= LoadConfigSettings;
}
}
else if (debugKey.GetValue("DbgManagedDebugger") != null) {
//if there is a debugger installed, check the config files to decide
//whether to allow JIT debugging.
wndProcFlags |= DebuggerPresent;
wndProcFlags |= LoadConfigSettings;
}
}
finally {
debugKey.Close();
}
}
finally {
System.Security.CodeAccessPermission.RevertAssert();
}
return wndProcFlags;
}
static int AdjustWndProcFlagsFromMetadata(int wndProcFlags) {
if ((wndProcFlags & DebuggerPresent) != 0) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Debugger present, checking for debuggable entry assembly");
Assembly entry = Assembly.GetEntryAssembly();
if (entry != null) {
if (Attribute.IsDefined(entry, typeof(DebuggableAttribute))) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Debuggable attribute on assembly");
Attribute[] attr = Attribute.GetCustomAttributes(entry, typeof(DebuggableAttribute));
if (attr.Length > 0) {
DebuggableAttribute dbg = (DebuggableAttribute)attr[0];
if (dbg.IsJITTrackingEnabled) {
// Only if the assembly is really setup for debugging
// does it really make sense to enable the jitDebugging
//
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Entry assembly is debuggable");
wndProcFlags |= AssemblyIsDebuggable;
}
}
}
}
}
return wndProcFlags;
}
///
///
/// Assigns a handle to this
/// window.
///
///
public void AssignHandle(IntPtr handle) {
AssignHandle(handle, true);
}
//
internal void AssignHandle(IntPtr handle, bool assignUniqueID) {
//
lock (this) {
CheckReleased();
Debug.Assert(handle != IntPtr.Zero, "handle is 0");
#if DEBUG
handleCreatedIn = AppDomain.CurrentDomain;
#endif
this.handle = handle;
if (userDefWindowProc == IntPtr.Zero) {
string defproc = (Marshal.SystemDefaultCharSize == 1 ? "DefWindowProcA" : "DefWindowProcW");
userDefWindowProc = UnsafeNativeMethods.GetProcAddress(new HandleRef(null, UnsafeNativeMethods.GetModuleHandle("user32.dll")), defproc);
if (userDefWindowProc == IntPtr.Zero) {
throw new Win32Exception();
}
}
defWindowProc = UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_WNDPROC);
Debug.Assert(defWindowProc != IntPtr.Zero, "defWindowProc is 0");
if (WndProcShouldBeDebuggable) {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Using debuggable wndproc");
windowProc = new NativeMethods.WndProc(this.DebuggableCallback);
}
else {
Debug.WriteLineIf(WndProcChoice.TraceVerbose, "Using normal wndproc");
windowProc = new NativeMethods.WndProc(this.Callback);
}
AddWindowToTable(handle, this);
UnsafeNativeMethods.SetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_WNDPROC, windowProc);
windowProcPtr = UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_WNDPROC);
Debug.Assert(defWindowProc != windowProcPtr, "Uh oh! Subclassed ourselves!!!");
if (assignUniqueID &&
(unchecked((int)((long)UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_STYLE))) & NativeMethods.WS_CHILD) != 0 &&
unchecked((int)((long)UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_ID))) == 0) {
UnsafeNativeMethods.SetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_ID, new HandleRef(this, handle));
}
if (suppressedGC) {
new SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Assert();
try {
GC.ReRegisterForFinalize(this);
}
finally {
CodeAccessPermission.RevertAssert();
}
suppressedGC = false;
}
OnHandleChange();
}
}
///
/// Window message callback method. Control arrives here when a window
/// message is sent to this Window. This method packages the window message
/// in a Message object and invokes the wndProc() method. A WM_NCDESTROY
/// message automatically causes the releaseHandle() method to be called.
///
///
/// Raises an exception if the window handle is not zero.
///
///
///
/// Creates a window handle for this
/// window.
///
///
[
// The call to UnsafeNativeMethods.CreateWindowEx is actually an interop call...
System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Interoperability", "CA1404:CallGetLastErrorImmediatelyAfterPInvoke")
]
public virtual void CreateHandle(CreateParams cp) {
Debug.WriteLineIf(IntSecurity.SecurityDemand.TraceVerbose, "CreateAnyWindow Demanded");
IntSecurity.CreateAnyWindow.Demand();
if ((cp.Style & NativeMethods.WS_CHILD) != NativeMethods.WS_CHILD
|| cp.Parent == IntPtr.Zero) {
Debug.WriteLineIf(IntSecurity.SecurityDemand.TraceVerbose, "TopLevelWindow Demanded");
IntSecurity.TopLevelWindow.Demand();
}
//
lock (this) {
CheckReleased();
WindowClass windowClass = WindowClass.Create(cp.ClassName, cp.ClassStyle);
lock (createWindowSyncObject) {
// VSWhidbey 528778
// Why are we checking the handle again after calling CheckReleased()? It turns
// out the CLR will sometimes pump messages while we're waiting on the lock. If
// a message comes through (say a WM_ACTIVATE for the parent) which causes the
// handle to be created, we can try to create the handle twice for the same
// NativeWindow object. See bug for more details.
if (this.handle != IntPtr.Zero) {
return;
}
windowClass.targetWindow = this;
IntPtr modHandle = UnsafeNativeMethods.GetModuleHandle(null);
IntPtr createResult = IntPtr.Zero;
int lastWin32Error = 0;
// Win98 apparently doesn't believe in returning E_OUTOFMEMORY. They'd much
// rather just AV. So we catch this and then we re-throw an out of memory error.
//
try {
//(bug 109840)
//CreateWindowEx() is throwing because we're passing the WindowText arg with a string of length > 32767.
//It looks like the Windows call (CreateWindowEx) will only work
//for string lengths no greater than the max length of a 16 bit int (32767).
//We need to check the length of the string we're passing into CreateWindowEx().
//If it exceeds the max, we should take the substring....
if (cp.Caption != null && cp.Caption.Length > Int16.MaxValue) {
cp.Caption = cp.Caption.Substring(0, Int16.MaxValue);
}
createResult = UnsafeNativeMethods.CreateWindowEx(cp.ExStyle, windowClass.windowClassName,
cp.Caption, cp.Style, cp.X, cp.Y, cp.Width, cp.Height, new HandleRef(cp, cp.Parent), NativeMethods.NullHandleRef,
new HandleRef(null, modHandle), cp.Param);
lastWin32Error = Marshal.GetLastWin32Error();
}
catch (NullReferenceException e) {
throw new OutOfMemoryException(SR.GetString(SR.ErrorCreatingHandle), e);
}
windowClass.targetWindow = null;
Debug.WriteLineIf(CoreSwitches.PerfTrack.Enabled, "Handle created of type '" + cp.ClassName + "' with caption '" + cp.Caption + "' from NativeWindow of type '" + GetType().FullName + "'");
if (createResult == IntPtr.Zero) {
throw new Win32Exception(lastWin32Error, SR.GetString(SR.ErrorCreatingHandle));
}
ownHandle = true;
System.Internal.HandleCollector.Add(createResult, NativeMethods.CommonHandles.Window);
}
}
}
///
/// Window message callback method. Control arrives here when a window
/// message is sent to this Window. This method packages the window message
/// in a Message object and invokes the wndProc() method. A WM_NCDESTROY
/// message automatically causes the releaseHandle() method to be called.
///
///
/// Invokes the default window procedure associated with this Window. It is
/// an error to call this method when the Handle property is zero.
///
public void DefWndProc(ref Message m) {
if (previousWindow == null) {
if (defWindowProc == IntPtr.Zero) {
#if DEBUG
Debug.Fail("Can't find a default window procedure for message " + m.ToString() + " on class " + GetType().Name + " subclass status: " + subclassStatus);
#endif
// At this point, there isn't much we can do. There's a
// small chance the following line will allow the rest of
// the program to run, but don't get your hopes up.
m.Result = UnsafeNativeMethods.DefWindowProc(m.HWnd, m.Msg, m.WParam, m.LParam);
return;
}
m.Result = UnsafeNativeMethods.CallWindowProc(defWindowProc, m.HWnd, m.Msg, m.WParam, m.LParam);
}
else {
Debug.Assert(previousWindow != this, "Looping in our linked list");
m.Result = previousWindow.Callback(m.HWnd, m.Msg, m.WParam, m.LParam);
}
}
///
///
/// Destroys the
/// handle associated with this window.
///
///
public virtual void DestroyHandle() {
//
lock (this) {
if (handle != IntPtr.Zero) {
if (!UnsafeNativeMethods.DestroyWindow(new HandleRef(this, handle))) {
UnSubclass();
//then post a close and let it do whatever it needs to do on its own.
UnsafeNativeMethods.PostMessage(new HandleRef(this, handle), NativeMethods.WM_CLOSE, 0, 0);
}
handle = IntPtr.Zero;
ownHandle = false;
}
// Now that we have disposed, there is no need to finalize us any more. So
// Mark to the garbage collector that we no longer need finalization.
//
new SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Assert();
try {
GC.SuppressFinalize(this);
}
finally {
CodeAccessPermission.RevertAssert();
}
suppressedGC = true;
}
}
///
/// Increases the bucket count of this hashtable. This method is called from
/// the Insert method when the actual load factor of the hashtable reaches
/// the upper limit specified when the hashtable was constructed. The number
/// of buckets in the hashtable is increased to the smallest prime number
/// that is larger than twice the current number of buckets, and the entries
/// in the hashtable are redistributed into the new buckets using the cached
/// hashcodes.
///
private static void ExpandTable() {
// Allocate new Array
int oldhashsize = hashBuckets.Length;
int hashsize = GetPrime(1 + oldhashsize * 2);
// Don't replace any internal state until we've finished adding to the
// new bucket[]. This serves two purposes: 1) Allow concurrent readers
// to see valid hashtable contents at all times and 2) Protect against
// an OutOfMemoryException while allocating this new bucket[].
HandleBucket[] newBuckets = new HandleBucket[hashsize];
// rehash table into new buckets
int nb;
for (nb = 0; nb < oldhashsize; nb++) {
HandleBucket oldb = hashBuckets[nb];
if ((oldb.handle != IntPtr.Zero) && (oldb.handle != new IntPtr(-1))) {
// Now re-fit this entry into the table
//
uint seed = (uint)oldb.hash_coll & 0x7FFFFFFF;
uint incr = (uint)(1 + (((seed >> 5) + 1) % ((uint)newBuckets.Length - 1)));
do {
int bucketNumber = (int)(seed % (uint)newBuckets.Length);
if ((newBuckets[bucketNumber].handle == IntPtr.Zero) || (newBuckets[bucketNumber].handle == new IntPtr(-1))) {
newBuckets[bucketNumber].window = oldb.window;
newBuckets[bucketNumber].handle = oldb.handle;
newBuckets[bucketNumber].hash_coll |= oldb.hash_coll & 0x7FFFFFFF;
break;
}
newBuckets[bucketNumber].hash_coll |= unchecked((int)0x80000000);
seed += incr;
} while (true);
}
}
// New bucket[] is good to go - replace buckets and other internal state.
hashBuckets = newBuckets;
hashLoadSize = (int)(hashLoadFactor * hashsize);
if (hashLoadSize >= hashsize) {
hashLoadSize = hashsize - 1;
}
}
///
///
/// Retrieves the window associated with the specified
///
///
[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
public static NativeWindow FromHandle(IntPtr handle) {
if (handle != IntPtr.Zero && handleCount > 0) {
return GetWindowFromTable(handle);
}
return null;
}
///
/// Calculates a prime number of at least minSize using a static table, and
/// if we overflow it, we calculate directly.
///
private static int GetPrime(int minSize) {
if (minSize < 0) {
Debug.Fail("NativeWindow hashtable capacity overflow");
throw new OutOfMemoryException();
}
for (int i = 0; i < primes.Length; i++) {
int size = primes[i];
if (size >= minSize) return size;
}
//outside of our predefined table.
//compute the hard way.
for (int j = ((minSize - 2) | 1); j < Int32.MaxValue; j += 2) {
bool prime = true;
if ((j & 1) != 0) {
int target = (int)Math.Sqrt(j);
for (int divisor = 3; divisor < target; divisor += 2) {
if ((j % divisor) == 0) {
prime = false;
break;
}
}
if (prime) return j;
}
else {
if (j == 2) {
return j;
}
}
}
return minSize;
}
///
/// Returns the native window for the given handle, or null if
/// the handle is not in our hash table.
///
private static NativeWindow GetWindowFromTable(IntPtr handle) {
Debug.Assert(handle != IntPtr.Zero, "Zero handles cannot be stored in the table");
// Take a snapshot of buckets, in case another thread does a resize
HandleBucket[] buckets = hashBuckets;
uint seed;
uint incr;
int ntry = 0;
uint hashcode = InitHash(handle, buckets.Length, out seed, out incr);
HandleBucket b;
do {
int bucketNumber = (int)(seed % (uint)buckets.Length);
b = buckets[bucketNumber];
if (b.handle == IntPtr.Zero) {
return null;
}
if (((b.hash_coll & 0x7FFFFFFF) == hashcode) && handle == b.handle) {
if (b.window.IsAllocated) {
return (NativeWindow)b.window.Target;
}
}
seed += incr;
}
while (b.hash_coll < 0 && ++ntry < buckets.Length);
return null;
}
internal IntPtr GetHandleFromID(short id) {
IntPtr handle;
if (NativeWindow.hashForIdHandle == null || !NativeWindow.hashForIdHandle.TryGetValue(id, out handle)) {
handle = IntPtr.Zero;
}
return handle;
}
///
/// Computes the hash function: H(key, i) = h1(key) + i*h2(key, hashSize).
/// The out parameter 'seed' is h1(key), while the out parameter
/// 'incr' is h2(key, hashSize). Callers of this function should
/// add 'incr' each time through a loop.
///
private static uint InitHash(IntPtr handle, int hashsize, out uint seed, out uint incr) {
// Hashcode must be positive. Also, we must not use the sign bit, since
// that is used for the collision bit.
uint hashcode = ((uint)handle.GetHashCode()) & 0x7FFFFFFF;
seed = (uint)hashcode;
// Restriction: incr MUST be between 1 and hashsize - 1, inclusive for
// the modular arithmetic to work correctly. This guarantees you'll
// visit every bucket in the table exactly once within hashsize
// iterations. Violate this and it'll cause obscure bugs forever.
// If you change this calculation for h2(key), update putEntry too!
incr = (uint)(1 + (((seed >> 5) + 1) % ((uint)hashsize - 1)));
return hashcode;
}
///
///
/// Specifies a notification method that is called when the handle for a
/// window is changed.
///
///
protected virtual void OnHandleChange() {
}
///
/// On class load, we connect an event to Application to let us know when
/// the process or domain terminates. When this happens, we attempt to
/// clear our window class cache. We cannot destroy windows (because we don't
/// have access to their thread), and we cannot unregister window classes
/// (because the classes are in use by the windows we can't destroy). Instead,
/// we move the class and window procs to DefWndProc
///
[PrePrepareMethod]
private static void OnShutdown(object sender, EventArgs e) {
// If we still have windows allocated, we must sling them to userDefWindowProc
// or else they will AV if they get a message after the managed code has been
// removed. In debug builds, we assert and give the "ToString" of the native
// window. In retail we just detatch the window proc and let it go. Note that
// we cannot call DestroyWindow because this API will fail if called from
// an incorrect thread.
//
if (handleCount > 0) {
Debug.Assert(userDefWindowProc != IntPtr.Zero, "We have active windows but no user window proc?");
lock (internalSyncObject) {
for (int i = 0; i < hashBuckets.Length; i++) {
HandleBucket b = hashBuckets[i];
if (b.handle != IntPtr.Zero && b.handle != new IntPtr(-1)) {
HandleRef href = new HandleRef(b, b.handle);
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, new HandleRef(null, userDefWindowProc));
UnsafeNativeMethods.SetClassLong(href, NativeMethods.GCL_WNDPROC, userDefWindowProc);
UnsafeNativeMethods.PostMessage(href, NativeMethods.WM_CLOSE, 0, 0);
// Fish out the Window object, if it is valid, and NULL the handle pointer. This
// way the rest of winforms won't think the handle is still valid here.
if (b.window.IsAllocated) {
NativeWindow w = (NativeWindow)b.window.Target;
if (w != null) {
w.handle = IntPtr.Zero;
}
}
#if DEBUG && FINALIZATION_WATCH
Debug.Fail("Window did not clean itself up: " + b.owner);
#endif
b.window.Free();
}
hashBuckets[i].handle = IntPtr.Zero;
hashBuckets[i].hash_coll = 0;
}
handleCount = 0;
}
}
WindowClass.DisposeCache();
}
///
///
/// When overridden in a derived class,
/// manages an unhandled thread
/// exception.
///
///
protected virtual void OnThreadException(Exception e) {
}
///
///
/// Releases the handle associated with this window.
///
///
public virtual void ReleaseHandle() {
ReleaseHandle(true);
}
///
/// Releases the handle associated with this window. If handleValid
/// is true, this will unsubclass the window as well. HandleValid
/// should be false if we are releasing in response to a
/// WM_DESTROY. Unsubclassing during this message can cause problems
/// with XP's theme manager and it's not needed anyway.
///
private void ReleaseHandle(bool handleValid) {
if (handle != IntPtr.Zero) {
//
lock (this) {
if (handle != IntPtr.Zero) {
if (handleValid) {
UnSubclass();
}
RemoveWindowFromTable(handle, this);
if (ownHandle) {
System.Internal.HandleCollector.Remove(handle, NativeMethods.CommonHandles.Window);
ownHandle = false;
}
handle = IntPtr.Zero;
//if not finalizing already.
if (weakThisPtr.IsAlive && weakThisPtr.Target != null) {
OnHandleChange();
// Now that we have disposed, there is no need to finalize us any more. So
// Mark to the garbage collector that we no longer need finalization.
//
new SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Assert();
try {
GC.SuppressFinalize(this);
}
finally {
CodeAccessPermission.RevertAssert();
}
suppressedGC = true;
}
}
}
}
}
///
/// Removes an entry from this hashtable. If an entry with the specified
/// key exists in the hashtable, it is removed.
///
private static void RemoveWindowFromTable(IntPtr handle, NativeWindow window) {
Debug.Assert(handle != IntPtr.Zero, "Incorrect handle");
lock (internalSyncObject) {
uint seed;
uint incr;
// Assuming only one concurrent writer, write directly into buckets.
uint hashcode = InitHash(handle, hashBuckets.Length, out seed, out incr);
int ntry = 0;
NativeWindow prevWindow = window.PreviousWindow;
HandleBucket b;
int bn; // bucketNumber
do {
bn = (int)(seed % (uint)hashBuckets.Length); // bucketNumber
b = hashBuckets[bn];
if (((b.hash_coll & 0x7FFFFFFF) == hashcode) && handle == b.handle) {
bool should----Bucket = (window.nextWindow == null);
bool shouldReplaceBucket = IsRootWindowInListWithChildren(window);
// We need to fixup the link pointers of window here.
//
if (window.previousWindow != null) {
window.previousWindow.nextWindow = window.nextWindow;
}
if (window.nextWindow != null) {
window.nextWindow.defWindowProc = window.defWindowProc;
window.nextWindow.previousWindow = window.previousWindow;
}
window.nextWindow = null;
window.previousWindow = null;
if (shouldReplaceBucket) {
// Free the existing GC handle
if (hashBuckets[bn].window.IsAllocated) {
hashBuckets[bn].window.Free();
}
hashBuckets[bn].window = GCHandle.Alloc(prevWindow, GCHandleType.Weak);
}
else if (should----Bucket) {
// Clear hash_coll field, then key, then value
hashBuckets[bn].hash_coll &= unchecked((int)0x80000000);
if (hashBuckets[bn].hash_coll != 0) {
hashBuckets[bn].handle = new IntPtr(-1);
}
else {
hashBuckets[bn].handle = IntPtr.Zero;
}
if (hashBuckets[bn].window.IsAllocated) {
hashBuckets[bn].window.Free();
}
Debug.Assert(handleCount > 0, "Underflow on handle count");
handleCount--;
}
return;
}
seed += incr;
} while (hashBuckets[bn].hash_coll < 0 && ++ntry < hashBuckets.Length);
}
}
///
/// Determines if the given window is the first member of the linked list
///
private static bool IsRootWindowInListWithChildren(NativeWindow window) {
// This seems backwards, but it isn't. When a new subclass comes in,
// it's previousWindow field is set to the previous subclass. Therefore,
// the top of the subclass chain has nextWindow == null and previousWindow
// == the first child subclass.
return ((window.PreviousWindow != null) && (window.nextWindow == null));
}
///
/// Determines if the given window is the first member of the linked list
/// and has no children
///
/* No one is calling this private method, so it is safe to comment it out.
private static bool IsRootWindowInListWithNoChildren(NativeWindow window)
{
return ((window.PreviousWindow == null) && (window.nextWindow == null));
}
*/
///
/// Inserts an entry into this ID hashtable.
///
internal static void RemoveWindowFromIDTable(IntPtr handle) {
short id = (short)NativeWindow.hashForHandleId[handle];
NativeWindow.hashForHandleId.Remove(handle);
NativeWindow.hashForIdHandle.Remove(id);
}
///
/// This method can be used to modify the exception handling behavior of
/// NativeWindow. By default, NativeWindow will detect if an application
/// is running under a debugger, or is running on a machine with a debugger
/// installed. In this case, an unhandled exception in the NativeWindow's
/// WndProc method will remain unhandled so the debugger can trap it. If
/// there is no debugger installed NativeWindow will trap the exception
/// and route it to the Application class's unhandled exception filter.
///
/// You can control this behavior via a config file, or directly through
/// code using this method. Setting the unhandled exception mode does
/// not change the behavior of any NativeWindow objects that are currently
/// connected to window handles; it only affects new handle connections.
///
/// When threadScope is false, the application exception mode is set. The
/// application exception mode is used for all threads that have the Automatic mode.
/// Setting the application exception mode does not affect the setting of the current thread.
///
/// When threadScope is true, the thread exception mode is set. The thread
/// exception mode overrides the application exception mode if it's not Automatic.
///
internal static void SetUnhandledExceptionModeInternal(UnhandledExceptionMode mode, bool threadScope) {
if (!threadScope && anyHandleCreatedInApp) {
throw new InvalidOperationException(SR.GetString(SR.ApplicationCannotChangeApplicationExceptionMode));
}
if (threadScope && anyHandleCreated) {
throw new InvalidOperationException(SR.GetString(SR.ApplicationCannotChangeThreadExceptionMode));
}
switch (mode) {
case UnhandledExceptionMode.Automatic:
if (threadScope) {
userSetProcFlags = 0;
}
else {
userSetProcFlagsForApp = 0;
}
break;
case UnhandledExceptionMode.ThrowException:
if (threadScope) {
userSetProcFlags = UseDebuggableWndProc | InitializedFlags;
}
else {
userSetProcFlagsForApp = UseDebuggableWndProc | InitializedFlags;
}
break;
case UnhandledExceptionMode.CatchException:
if (threadScope) {
userSetProcFlags = InitializedFlags;
}
else {
userSetProcFlagsForApp = InitializedFlags;
}
break;
default:
throw new InvalidEnumArgumentException("mode", (int)mode, typeof(UnhandledExceptionMode));
}
}
///
/// Unsubclassing is a tricky business. We need to account for
/// some border cases:
///
/// 1) User has done multiple subclasses but has un-subclassed out of order.
/// 2) User has done multiple subclasses but now our defWindowProc points to
/// a NativeWindow that has GC'd
/// 3) User releasing this handle but this NativeWindow is not the current
/// window proc.
///
private void UnSubclass() {
bool finalizing = (!weakThisPtr.IsAlive || weakThisPtr.Target == null);
HandleRef href = new HandleRef(this, handle);
// Don't touch if the current window proc is not ours.
//
IntPtr currentWinPrc = UnsafeNativeMethods.GetWindowLong(new HandleRef(this, handle), NativeMethods.GWL_WNDPROC);
if (windowProcPtr == currentWinPrc) {
if (previousWindow == null) {
#if DEBUG
subclassStatus = "Unsubclassing back to native defWindowProc";
#endif
// If the defWindowProc points to a native window proc, previousWindow will
// be null. In this case, it is completely safe to assign defWindowProc
// to the current wndproc.
//
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, new HandleRef(this, defWindowProc));
}
else {
if (finalizing) {
#if DEBUG
subclassStatus = "Setting back to userDefWindowProc -- next chain is managed";
#endif
// Here, we are finalizing and defWindowProc is pointing to a managed object. We must assume
// that the object defWindowProc is pointing to is also finalizing. Why? Because we're
// holding a ref to it, and it is holding a ref to us. The only way this cycle will
// finalize is if no one else is hanging onto it. So, we re-assign the window proc to
// userDefWindowProc.
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, new HandleRef(this, userDefWindowProc));
}
else {
#if DEBUG
subclassStatus = "Setting back to next managed subclass object";
#endif
// Here we are not finalizing so we use the windowProc for our previous window. This may
// DIFFER from the value we are currently storing in defWindowProc because someone may
// have re-subclassed.
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, previousWindow.windowProc);
}
}
}
else {
// cutting the subclass chain anyway, even if we're not the last one in the chain
// if the whole chain is all managed NativeWindow it doesnt matter,
// if the chain is not, then someone has been dirty and didn't clean up properly, too bad for them...
//We will cut off the chain if we cannot unsubclass.
//If we find previouswindow pointing to us, then we can let RemoveWindowFromTable reassign the
//defwndproc pointers properly when this guy gets removed (thereby unsubclassing ourselves)
if (nextWindow == null || nextWindow.defWindowProc != windowProcPtr) {
// we didn't find it... let's unhook anyway and cut the chain... this prevents crashes
UnsafeNativeMethods.SetWindowLong(href, NativeMethods.GWL_WNDPROC, new HandleRef(this, userDefWindowProc));
}
#if DEBUG
subclassStatus = "FORCE unsubclass -- we do not own the subclass";
#endif
}
}
///
///
/// Invokes the default window procedure associated with
/// this window.
///
///
protected virtual void WndProc(ref Message m) {
DefWndProc(ref m);
}
///
/// A struct that contains a single bucket for our handle / GCHandle hash table.
/// The hash table algorithm we use here was stolen selfishly from the framework's
/// Hashtable class. We don't use Hashtable directly, however, because of boxing
/// concerns. It's algorithm is perfect for our needs, however: Multiple
/// reader, single writer without the need for locks and constant lookup time.
///
/// Differences between this implementation and Hashtable:
///
/// Keys are IntPtrs; their hash code is their value. Collision is still
/// marked with the high bit.
///
/// Reclaimed buckets store -1 in their handle, not the hash table reference.
///
private struct HandleBucket {
public IntPtr handle; // Win32 window handle
public GCHandle window; // a weak GC handle to the NativeWindow class
public int hash_coll; // Store hash code; sign bit means there was a collision.
#if DEBUG
public string owner; // owner of this handle
#endif
}
///
/// WindowClass encapsulates a window class.
///
///
/// Retrieves a WindowClass object for use. This will create a new
/// object if there is no such class/style available, or retrun a
/// cached object if one exists.
///
internal static WindowClass Create(string className, int classStyle) {
lock (wcInternalSyncObject) {
WindowClass wc = cache;
if (className == null) {
while (wc != null && (wc.className != null ||
wc.classStyle != classStyle)) wc = wc.next;
}
else {
while (wc != null &&
!className.Equals(wc.className)) {
wc = wc.next;
}
}
if (wc == null) {
wc = new WindowClass(className, classStyle);
wc.next = cache;
cache = wc;
}
else {
if (!wc.registered) {
wc.RegisterClass();
}
}
return wc;
}
}
///
/// Disposes our window class cache. This doesn't free anything
/// from the actual cache; it merely attempts to unregister
/// the classes of everything in the cache. This allows the unused
/// classes to be unrooted. They can later be re-rooted and reused.
///
internal static void DisposeCache() {
lock (wcInternalSyncObject) {
WindowClass wc = cache;
while (wc != null) {
wc.UnregisterClass();
wc = wc.next;
}
}
}
///
/// Fabricates a full class name from a partial.
///
private string GetFullClassName(string className) {
StringBuilder b = new StringBuilder(50);
b.Append(Application.WindowsFormsVersion);
b.Append('.');
b.Append(className);
b.Append(".app.");
b.Append(domainQualifier);
b.Append('.');
b.Append(Convert.ToString(AppDomain.CurrentDomain.GetHashCode(), 16));
return b.ToString();
}
///
/// Once the classname and style bits have been set, this can
/// be called to register the class.
///
private void RegisterClass() {
NativeMethods.WNDCLASS_D wndclass = new NativeMethods.WNDCLASS_D();
if (userDefWindowProc == IntPtr.Zero) {
string defproc = (Marshal.SystemDefaultCharSize == 1 ? "DefWindowProcA" : "DefWindowProcW");
userDefWindowProc = UnsafeNativeMethods.GetProcAddress(new HandleRef(null, UnsafeNativeMethods.GetModuleHandle("user32.dll")), defproc);
if (userDefWindowProc == IntPtr.Zero) {
throw new Win32Exception();
}
}
string localClassName = className;
if (localClassName == null) {
// If we don't use a hollow brush here, Windows will "pre paint" us with COLOR_WINDOW which
// creates a little bit if flicker. This happens even though we are overriding wm_erasebackgnd.
// Make this hollow to avoid all flicker.
//
wndclass.hbrBackground = UnsafeNativeMethods.GetStockObject(NativeMethods.HOLLOW_BRUSH); //(IntPtr)(NativeMethods.COLOR_WINDOW + 1);
wndclass.style = classStyle;
defWindowProc = userDefWindowProc;
localClassName = "Window." + Convert.ToString(classStyle, 16);
hashCode = 0;
}
else {
NativeMethods.WNDCLASS_I wcls = new NativeMethods.WNDCLASS_I();
bool ok = UnsafeNativeMethods.GetClassInfo(NativeMethods.NullHandleRef, className, wcls);
int error = Marshal.GetLastWin32Error();
if (!ok) {
throw new Win32Exception(error, SR.GetString(SR.InvalidWndClsName));
}
wndclass.style = wcls.style;
wndclass.cbClsExtra = wcls.cbClsExtra;
wndclass.cbWndExtra = wcls.cbWndExtra;
wndclass.hIcon = wcls.hIcon;
wndclass.hCursor = wcls.hCursor;
wndclass.hbrBackground = wcls.hbrBackground;
wndclass.lpszMenuName = Marshal.PtrToStringAuto(wcls.lpszMenuName);
localClassName = className;
defWindowProc = wcls.lpfnWndProc;
hashCode = className.GetHashCode();
}
// Our static data is different for different app domains, so we include the app domain in with
// our window class name. This way our static table always matches what Win32 thinks.
//
windowClassName = GetFullClassName(localClassName);
windowProc = new NativeMethods.WndProc(this.Callback);
wndclass.lpfnWndProc = windowProc;
wndclass.hInstance = UnsafeNativeMethods.GetModuleHandle(null);
wndclass.lpszClassName = windowClassName;
short atom = UnsafeNativeMethods.RegisterClass(wndclass);
if (atom == 0) {
int err = Marshal.GetLastWin32Error();
if (err == NativeMethods.ERROR_CLASS_ALREADY_EXISTS) {
// Check to see if the window class window
// proc points to DefWndProc. If it does, then
// this is a class from a rudely-terminated app domain
// and we can safely reuse it. If not, we've got
// to throw.
NativeMethods.WNDCLASS_I wcls = new NativeMethods.WNDCLASS_I();
bool ok = UnsafeNativeMethods.GetClassInfo(new HandleRef(null, UnsafeNativeMethods.GetModuleHandle(null)), windowClassName, wcls);
if (ok && wcls.lpfnWndProc == NativeWindow.UserDefindowProc) {
// We can just reuse this class because we have marked it
// as being a nop in another domain. All we need to do is call SetClassLong.
// Only one problem: SetClassLong takes an HWND, which we don't have. That leaves
// us with some tricky business. First, try this the easy way and see
// if we can simply unregister and re-register the class. This might
// work because the other domain shutdown would have posted WM_CLOSE to all
// the windows of the class.
if (UnsafeNativeMethods.UnregisterClass(windowClassName, new HandleRef(null, UnsafeNativeMethods.GetModuleHandle(null)))) {
atom = UnsafeNativeMethods.RegisterClass(wndclass);
// If this fails, we will always raise the first err above. No sense exposing our twiddling.
}
else {
// This is a little harder. We cannot reuse the class because it is
// already in use. We must create a new class. We bump our domain qualifier
// here to account for this, so we only do this expensive search once for the
// domain.
do {
domainQualifier++;
windowClassName = GetFullClassName(localClassName);
wndclass.lpszClassName = windowClassName;
atom = UnsafeNativeMethods.RegisterClass(wndclass);
} while (atom == 0 && Marshal.GetLastWin32Error() == NativeMethods.ERROR_CLASS_ALREADY_EXISTS);
}
}
}
if (atom == 0) {
windowProc = null;
throw new Win32Exception(err);
}
}
registered = true;
}
///
/// Unregisters this window class. Unregistration is not a
/// last resort; the window class may be re-registered through
/// a call to registerClass.
///
private void UnregisterClass() {
if (registered && UnsafeNativeMethods.UnregisterClass(windowClassName, new HandleRef(null, UnsafeNativeMethods.GetModuleHandle(null)))) {
windowProc = null;
registered = false;
}
}
}
}
///
/// Determines the exception mode of NativeWindow's WndProc method. Pass
/// a value of this enum into SetUnhandledExceptionMode to control how
/// new NativeWindow objects handle exceptions.
///
public enum UnhandledExceptionMode {
Automatic,
ThrowException,
CatchException
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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