Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / System / Windows / Media / VisualProxy.cs / 1305600 / VisualProxy.cs
//------------------------------------------------------------------------------ // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // Description: // Mapping between a visual and its handles on different channels. // //----------------------------------------------------------------------------- namespace System.Windows.Media.Composition { using System; using System.Collections; using System.Collections.Generic; using System.Diagnostics; using System.Windows; using System.Windows.Media; ////// Mapping between a visual and its handles on different channels. /// internal struct VisualProxy { // ------------------------------------------------------------------- // // Private Types // // ------------------------------------------------------------------- #region Private Types ////// Tuple binding a channel to a set of flags and a resource handle. /// ////// Note that DUCE.Channel is a reference type. /// private struct Proxy { internal DUCE.Channel Channel; internal VisualProxyFlags Flags; internal DUCE.ResourceHandle Handle; } #endregion Private Types // -------------------------------------------------------------------- // // Internal Properties // // ------------------------------------------------------------------- #region Internal Properties ////// Returns the number of channels this resource is marshaled to. /// internal int Count { get { if (_tail == null) { return _head.Channel == null ? 0 : 1; } else { // // The logic here is simple: we keep at most one entry // in the tail free. Heads has to be occupied and adds one. // int tailLength = _tail.Length; bool lastTailIsEmpty = _tail[tailLength - 1].Channel == null; return 1 + tailLength - (lastTailIsEmpty ? 1 : 0); } } } ////// Returns true if the parent resource is marshaled to at least /// one channel. /// internal bool IsOnAnyChannel { get { return Count != 0; } } #endregion Internal Properties // -------------------------------------------------------------------- // // Internal Methods // // -------------------------------------------------------------------- #region Internal Methods ////// Returns true if the visual is marshaled to the /// specified channel. /// internal bool IsOnChannel(DUCE.Channel channel) { int index = Find(channel); if (index == PROXY_NOT_FOUND) { return false; } else if (index == PROXY_STORED_INLINE) { return !_head.Handle.IsNull; } else { return !_tail[index].Handle.IsNull; } } ////// If the visual is on channel, its reference count is increased. /// Otherwise, a new resource is created on that channel. /// internal bool CreateOrAddRefOnChannel( object instance, DUCE.Channel channel, DUCE.ResourceType resourceType) { int index = Find(channel); int count = Count; if (index == PROXY_NOT_FOUND) { // // This is the case where we have to create a new resource. // if (_head.Channel == null) { // // We're adding the first proxy. // // Before: [empty] // After insert: [ head] // Debug.Assert(count == 0); _head.Channel = channel; _head.Flags = VisualProxyFlags.None; channel.CreateOrAddRefOnChannel( instance, ref _head.Handle, resourceType); } else { if (_tail == null) { // // We're adding the second proxy. // // Before: [head] // After resize: [head] [ empty] [empty] // After insert: [head] [tail 0] [empty] // ---------------- Debug.Assert(count == 1); _tail = new Proxy[2]; } else if (count > _tail.Length) { // // Increase the tail size by 2. // // Before: [head] [tail 0] ... [tail c-2] // After resize: [head] [tail 0] ... [tail c-2] [ empty] [empty] // After insert: [head] [tail 0] ... [tail c-3] [tail c-2] [empty] // ------------------------------------------ // ResizeTail(2); } // // Now that we have a tail, fill in the first free element. // Proxy proxy; proxy.Channel = channel; proxy.Flags = VisualProxyFlags.None; proxy.Handle = DUCE.ResourceHandle.Null; channel.CreateOrAddRefOnChannel( instance, ref proxy.Handle, resourceType); _tail[count - 1] = proxy; } return /* created */ true; } else if (index == PROXY_STORED_INLINE) { // // We simply need to increase the reference count on head... // channel.CreateOrAddRefOnChannel( instance, ref _head.Handle, resourceType); } else { // // Increase the reference count on one of the tail proxies... // channel.CreateOrAddRefOnChannel( instance, ref _tail[index].Handle, resourceType); } return /* not created */ false; } ////// If visual is on channel, its reference count is increased. /// Otherwise, a new resource is created on that channel. /// internal bool ReleaseOnChannel(DUCE.Channel channel) { int index = Find(channel); bool proxyRemoved = false; int count = Count; if (index == PROXY_STORED_INLINE) { if (channel.ReleaseOnChannel(_head.Handle)) { // // Need to move the last of the non-empty tail to head // or clear the head. Erase the head if that was the last // proxy. // if (count == 1) { _head = new Proxy(); } else { _head = _tail[count - 2]; } proxyRemoved = true; } } else if (index >= 0) { if (channel.ReleaseOnChannel(_tail[index].Handle)) { // // Need to move the last of the non-empty tail to the // removed index. Avoid in-place copying. // if (index != count - 2) { _tail[index] = _tail[count - 2]; } proxyRemoved = true; } } else { Debug.Assert(index != PROXY_NOT_FOUND); return false; } if (proxyRemoved) { if (_tail != null) { // // Keep the tail short. We allow for one extra free element // in tail to avoid constant allocations / reallocations. // if (count == 2) { // ------------------ // Before removal: [head] [tail c-1] [empty] // Here and now: [head] [ deleted] [empty] // After removal: [head] // _tail = null; } else if (count == _tail.Length) { // --------------------------------------------------- // Before removal: [head] [tail 0] [tail 1] ... [tail c-3] [tail c-2] [empty] // Here and now: [head] [tail 0] [tail 1] ... [tail c-3] [ deleted] [empty] // After removal: [head] [tail 0] [tail 1] ... [tail c-3] // ResizeTail(-2); } else { // ------------------------------------------------------ // Before removal: [head] [tail 0] [tail 1] ... [tail c-4] [tail c-3] [tail c-2] // Here and now: [head] [tail 0] [tail 1] ... [tail c-4] [tail c-3] [ deleted] // After removal: [head] [tail 0] [tail 1] ... [tail c-4] [tail c-3] [ empty] // _tail[count - 2] = new Proxy(); } } } return proxyRemoved; } ////// Returns the channel that the n-th proxy connects to. /// internal DUCE.Channel GetChannel(int index) { Debug.Assert(index >= 0 && index < Count); if (index < Count) { if (index == 0) { return _head.Channel; } else if (index > 0) { return _tail[index - 1].Channel; } } return null; } #endregion Internal Methods // --------------------------------------------------------------- // // Internal Methods: resource handle getters // // --------------------------------------------------------------- #region Internal Methods: resource handle getters ////// Returns the handle the visual has on a specific channel. /// internal DUCE.ResourceHandle GetHandle(DUCE.Channel channel) { return GetHandle(Find(channel) + 1); // Find's results are -1 based, adjust by one. } ////// Returns the handle the visual has on the n-th channel. /// internal DUCE.ResourceHandle GetHandle(int index) { Debug.Assert(index >= 0 && index < Count); if (index < Count) { if (index == 0) { return _head.Handle; } else if (index > 0) { return _tail[index - 1].Handle; } } return DUCE.ResourceHandle.Null; } #endregion Internal Methods: resource handle getters // --------------------------------------------------------------- // // Internal Methods: visual proxy flags // // ---------------------------------------------------------------- #region Internal Methods: visual proxy flags ////// Returns the flags the visual has on a specific channel. /// internal VisualProxyFlags GetFlags(DUCE.Channel channel) { return GetFlags(Find(channel) + 1); // Find's results are -1 based, adjust by one. } ////// Returns the handle the visual has on n-th channel. /// internal VisualProxyFlags GetFlags(int index) { if (index < Count) { if (index == 0) { return _head.Flags; } else if (index > 0) { return _tail[index - 1].Flags; } } return VisualProxyFlags.None; } ////// Sets the flags the visual has on a specific channel. /// internal void SetFlags( DUCE.Channel channel, bool value, VisualProxyFlags flags) { SetFlags(Find(channel) + 1, value, flags); // Find's results are -1 based, adjust by one. } ////// Sets the flags the visual has on the n-th channel. /// internal void SetFlags( int index, bool value, VisualProxyFlags flags) { Debug.Assert(index >= 0 && index < Count); if (index < Count) { if (index == 0) { _head.Flags = value ? (_head.Flags | flags) : (_head.Flags & ~flags); } else if (index > 0) { _tail[index - 1].Flags = value ? (_tail[index - 1].Flags | flags) : (_tail[index - 1].Flags & ~flags); } } } ////// Sets the flags on all channels the visual is marshaled to. /// internal void SetFlagsOnAllChannels( bool value, VisualProxyFlags flags) { if (_head.Channel != null) { _head.Flags = value ? (_head.Flags | flags) : (_head.Flags & ~flags); for (int i = 0, limit = Count - 1; i < limit; i++) { _tail[i].Flags = value ? (_tail[i].Flags | flags) : (_tail[i].Flags & ~flags); } } } ////// Returns true if the given flags are set for every proxy or if /// the visual is not being marshaled. /// internal bool CheckFlagsOnAllChannels( VisualProxyFlags conjunctionFlags) { if (_head.Channel != null) { if ((_head.Flags & conjunctionFlags) != conjunctionFlags) return false; for (int i = 0, limit = Count - 1; i < limit; i++) { if ((_tail[i].Flags & conjunctionFlags) != conjunctionFlags) return false; } } return true; } #endregion Internal Methods: visual proxy flags // ------------------------------------------------------------------- // // Private Methods // // -------------------------------------------------------------------- #region Private Methods ////// Looks for the given channel in the proxies list. /// private int Find(DUCE.Channel channel) { if (_head.Channel == channel) { return PROXY_STORED_INLINE; } else if (_tail != null) { for (int i = 0, limit = Count - 1; i < limit; i++) { if (_tail[i].Channel == channel) { return i; } } } return PROXY_NOT_FOUND; } ////// Grows or shrinks the tail by a given size. /// private void ResizeTail(int delta) { int newLength = _tail.Length + delta; Debug.Assert(delta % 2 == 0 && newLength >= 2); Proxy[] reallocatedTail = new Proxy[newLength]; Array.Copy(_tail, reallocatedTail, Math.Min(_tail.Length, newLength)); _tail = reallocatedTail; } #endregion Private Methods // -------------------------------------------------------------------- // // Private Fields // // ------------------------------------------------------------------- #region Private Fields ////// Returned by the Find method to denote that a proxy for the given /// channel has not been found. /// private const int PROXY_NOT_FOUND = -2; ////// Returned by the Find method to denote that a proxy for the given /// channel has been found in the inline storage. /// private const int PROXY_STORED_INLINE = -1; ////// This data structure is optimized for single entry. _head is /// the one entry that we inline into the struct for that purpose. /// private Proxy _head; ////// All the other entries end up in this array. /// private Proxy[] _tail; #endregion Private Fields } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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