XmlILModule.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / XmlUtils / System / Xml / Xsl / IlGen / XmlILModule.cs / 1305376 / XmlILModule.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
//----------------------------------------------------------------------------- 
 
using System.Collections;
using System.Diagnostics; 
using System.Diagnostics.SymbolStore;
using System.Reflection;
using System.Reflection.Emit;
using System.Security; 
using System.Security.Permissions;
using System.Xml.Xsl.Runtime; 
using System.Runtime.Versioning; 

namespace System.Xml.Xsl.IlGen { 
    using DebuggingModes = DebuggableAttribute.DebuggingModes;

    internal enum XmlILMethodAttributes {
        None = 0, 
        NonUser = 1,    // Non-user method which should debugger should step through
        Raw = 2,        // Raw method which should not add an implicit first argument of type XmlQueryRuntime 
    } 

    internal class XmlILModule { 
        public static readonly PermissionSet CreateModulePermissionSet;     // Permission set that contains permissions required for generating module
        private static long AssemblyId;                                     // Unique identifier used to ensure that assembly names are unique within AppDomain
        private static ModuleBuilder LREModule;                             // Module used to emit dynamic lightweight-reflection-emit (LRE) methods
 
        private TypeBuilder typeBldr;
        private Hashtable methods, urlToSymWriter; 
        private string modFile; 
        private bool persistAsm, useLRE, emitSymbols;
 
        private static readonly Guid LanguageGuid = new Guid(0x462d4a3e, 0xb257, 0x4aee, 0x97, 0xcd, 0x59, 0x18, 0xc7, 0x53, 0x17, 0x58);
        private static readonly Guid VendorGuid = new Guid(0x994b45c4, 0xe6e9, 0x11d2, 0x90, 0x3f, 0x00, 0xc0, 0x4f, 0xa3, 0x02, 0xa1);
        private const string RuntimeName = "{" + XmlReservedNs.NsXslDebug + "}" + "runtime";
 
        static XmlILModule() {
            AssemblyName asmName; 
            AssemblyBuilder asmBldr; 

            CreateModulePermissionSet = new PermissionSet(PermissionState.None); 
            // CreateDelegate demands MemberAccess permission
            CreateModulePermissionSet.AddPermission(new ReflectionPermission(ReflectionPermissionFlag.MemberAccess));
            // DynamicMethod constructor demands ControlEvidence permissions.
            // Emitting symbols in DefineDynamicModule (to allow to debug the stylesheet) requires UnmanagedCode permission. 
            CreateModulePermissionSet.AddPermission(new SecurityPermission(SecurityPermissionFlag.ControlEvidence | SecurityPermissionFlag.UnmanagedCode));
 
            AssemblyId = 0; 

            // 1. LRE assembly only needs to execute 
            // 2. No temp files need be created
            // 3. Never allow assembly to Assert permissions
            asmName = CreateAssemblyName();
            asmBldr = AppDomain.CurrentDomain.DefineDynamicAssembly(asmName, AssemblyBuilderAccess.Run); 

            try { 
                CreateModulePermissionSet.Assert(); 

                // Add custom attribute to assembly marking it as security transparent so that Assert will not be allowed 
                // and link demands will be converted to full demands.
                asmBldr.SetCustomAttribute(new CustomAttributeBuilder(XmlILConstructors.Transparent, new object[] {}));

                // Store LREModule once.  If multiple threads are doing this, then some threads might get different 
                // modules.  This is OK, since it's not mandatory to share, just preferable.
                LREModule = asmBldr.DefineDynamicModule("System.Xml.Xsl.CompiledQuery", false); 
            } 
            finally {
                CodeAccessPermission.RevertAssert(); 
            }
        }

        public XmlILModule(TypeBuilder typeBldr) { 
            this.typeBldr = typeBldr;
 
            this.emitSymbols = ((ModuleBuilder) this.typeBldr.Module).GetSymWriter() != null; 
            this.useLRE = false;
            this.persistAsm = false; 

            // Index all methods added to this module by unique name
            this.methods = new Hashtable();
 
            if (this.emitSymbols) {
                // Create mapping from source document to symbol writer 
                this.urlToSymWriter = new Hashtable(); 
            }
        } 

        public bool EmitSymbols {
            get {
                return this.emitSymbols; 
            }
        } 
 
        // SxS note: AssemblyBuilder.DefineDynamicModule() below may be using name which is not SxS safe.
        // This file is written only for internal tracing/debugging purposes. In retail builds persistAsm 
        // will be always false and the file should never be written. As a result it's fine just to supress
        // the the SxS warning.
        [ResourceConsumption(ResourceScope.Machine, ResourceScope.Machine)]
        [ResourceExposure(ResourceScope.None)] 
        public XmlILModule(bool useLRE, bool emitSymbols) {
            AssemblyName asmName; 
            AssemblyBuilder asmBldr; 
            ModuleBuilder modBldr;
            Debug.Assert(!(useLRE && emitSymbols)); 

            this.useLRE = useLRE;
            this.emitSymbols = emitSymbols;
            this.persistAsm = false; 

            // Index all methods added to this module by unique name 
            this.methods = new Hashtable(); 

            if (!useLRE) { 
                // 1. If assembly needs to support debugging, then it must be saved and re-loaded (rule of CLR)
                // 2. Get path of temp directory, where assembly will be saved
                // 3. Never allow assembly to Assert permissions
                asmName = CreateAssemblyName(); 

            #if DEBUG 
                if (XmlILTrace.IsEnabled) { 
                    this.modFile = "System.Xml.Xsl.CompiledQuery";
                    this.persistAsm = true; 
                }
            #endif

                asmBldr = AppDomain.CurrentDomain.DefineDynamicAssembly( 
                            asmName,
                            this.persistAsm ? AssemblyBuilderAccess.RunAndSave : AssemblyBuilderAccess.Run); 
 
                // Add custom attribute to assembly marking it as security transparent so that Assert will not be allowed
                // and link demands will be converted to full demands. 
                asmBldr.SetCustomAttribute(new CustomAttributeBuilder(XmlILConstructors.Transparent, new object[] { }));

                if (emitSymbols) {
                    // Create mapping from source document to symbol writer 
                    this.urlToSymWriter = new Hashtable();
 
                    // Add DebuggableAttribute to assembly so that debugging is a better experience 
                    DebuggingModes debuggingModes = DebuggingModes.Default | DebuggingModes.IgnoreSymbolStoreSequencePoints | DebuggingModes.DisableOptimizations;
                    asmBldr.SetCustomAttribute(new CustomAttributeBuilder(XmlILConstructors.Debuggable, new object[] {debuggingModes})); 
                }

                // Create ModuleBuilder
                if (this.persistAsm) 
                    modBldr = asmBldr.DefineDynamicModule("System.Xml.Xsl.CompiledQuery", this.modFile + ".dll", emitSymbols);
                else 
                    modBldr = asmBldr.DefineDynamicModule("System.Xml.Xsl.CompiledQuery", emitSymbols); 

                this.typeBldr = modBldr.DefineType("System.Xml.Xsl.CompiledQuery.Query", TypeAttributes.Public); 
            }
        }

        ///  
        /// Define a method in this module with the specified name and parameters.
        ///  
        public MethodInfo DefineMethod(string name, Type returnType, Type[] paramTypes, string[] paramNames, XmlILMethodAttributes xmlAttrs) { 
            MethodInfo methResult;
            int uniqueId = 1; 
            string nameOrig = name;
            Type[] paramTypesNew;
            bool isRaw = (xmlAttrs & XmlILMethodAttributes.Raw) != 0;
 
            // Ensure that name is unique
            while (this.methods[name] != null) { 
                // Add unique id to end of name in order to make it unique within this module 
                uniqueId++;
                name = nameOrig + " (" + uniqueId + ")"; 
            }

            if (!isRaw) {
                // XmlQueryRuntime is always 0th parameter 
                paramTypesNew = new Type[paramTypes.Length + 1];
                paramTypesNew[0] = typeof(XmlQueryRuntime); 
                Array.Copy(paramTypes, 0, paramTypesNew, 1, paramTypes.Length); 
                paramTypes = paramTypesNew;
            } 

            if (!this.useLRE) {
                MethodBuilder methBldr;
 
                methBldr = this.typeBldr.DefineMethod(
                            name, 
                            MethodAttributes.Private | MethodAttributes.Static, 
                            returnType,
                            paramTypes); 

                if (emitSymbols && (xmlAttrs & XmlILMethodAttributes.NonUser) != 0) {
                    // Add DebuggerStepThroughAttribute and DebuggerNonUserCodeAttribute to non-user methods so that debugging is a better experience
                    methBldr.SetCustomAttribute(new CustomAttributeBuilder(XmlILConstructors.StepThrough, new object[] {})); 
                    methBldr.SetCustomAttribute(new CustomAttributeBuilder(XmlILConstructors.NonUserCode, new object[] {}));
                } 
 
                if (!isRaw)
                    methBldr.DefineParameter(1, ParameterAttributes.None, RuntimeName); 

                for (int i = 0; i < paramNames.Length; i++) {
                    if (paramNames[i] != null && paramNames[i].Length != 0)
                        methBldr.DefineParameter(i + (isRaw ? 1 : 2), ParameterAttributes.None, paramNames[i]); 
                }
 
                methResult = methBldr; 
            }
            else { 
                DynamicMethod methDyn = new DynamicMethod(name, returnType, paramTypes, LREModule);
                methDyn.InitLocals = true;

                if (!isRaw) 
                    methDyn.DefineParameter(1, ParameterAttributes.None, RuntimeName);
 
                for (int i = 0; i < paramNames.Length; i++) { 
                    if (paramNames[i] != null && paramNames[i].Length != 0)
                        methDyn.DefineParameter(i + (isRaw ? 1 : 2), ParameterAttributes.None, paramNames[i]); 
                }

                methResult = methDyn;
            } 

            // Index method by name 
            this.methods[name] = methResult; 
            return methResult;
        } 

        /// 
        /// Get an XmlILGenerator that can be used to generate the body of the specified method.
        ///  
        public static ILGenerator DefineMethodBody(MethodBase methInfo) {
            DynamicMethod methDyn = methInfo as DynamicMethod; 
            if (methDyn != null) 
                return methDyn.GetILGenerator();
 
            MethodBuilder methBldr = methInfo as MethodBuilder;
            if (methBldr != null)
                return methBldr.GetILGenerator();
 
            return ((ConstructorBuilder) methInfo).GetILGenerator();
        } 
 
        /// 
        /// Find a MethodInfo of the specified name and return it.  Return null if no such method exists. 
        /// 
        public MethodInfo FindMethod(string name) {
            return (MethodInfo) this.methods[name];
        } 

        ///  
        /// Define ginitialized data field with the specified name and value. 
        /// 
        public FieldInfo DefineInitializedData(string name, byte[] data) { 
            Debug.Assert(!this.useLRE, "Cannot create initialized data for an LRE module");
            return this.typeBldr.DefineInitializedData(name, data, FieldAttributes.Private | FieldAttributes.Static);
        }
 
        /// 
        /// Define private static field with the specified name and value. 
        ///  
        public FieldInfo DefineField(string fieldName, Type type) {
            Debug.Assert(!this.useLRE, "Cannot create field for an LRE module"); 
            return this.typeBldr.DefineField(fieldName, type, FieldAttributes.Private | FieldAttributes.Static);
        }

        ///  
        /// Define static constructor for this type.
        ///  
        public ConstructorInfo DefineTypeInitializer() { 
            Debug.Assert(!this.useLRE, "Cannot create type initializer for an LRE module");
            return this.typeBldr.DefineTypeInitializer(); 
        }

        /// 
        /// Add the file name of a document containing source code for this module and return a symbol writer. 
        /// 
        public ISymbolDocumentWriter AddSourceDocument(string fileName) { 
            ISymbolDocumentWriter symDoc; 
            Debug.Assert(this.emitSymbols, "Cannot add source information to a module that doesn't allow symbols.");
 
            symDoc = this.urlToSymWriter[fileName] as ISymbolDocumentWriter;
            if (symDoc == null) {
                symDoc = ((ModuleBuilder) this.typeBldr.Module).DefineDocument(fileName, LanguageGuid, VendorGuid, Guid.Empty);
                this.urlToSymWriter.Add(fileName, symDoc); 
            }
 
            return symDoc; 
        }
 
        /// 
        /// Once all methods have been defined, CreateModule must be called in order to "bake" the methods within
        /// this module.
        ///  
        // SxS note: AssemblyBuilder.Save() below is using name which is not SxS safe. This file is written only for
        // internal tracing/debugging purposes. In retail builds persistAsm will be always false and the file should 
        // never be written. As a result it's fine just to supress the the SxS warning. 
        [ResourceConsumption(ResourceScope.Machine, ResourceScope.Machine)]
        [ResourceExposure(ResourceScope.None)] 
        public void BakeMethods() {
            Type typBaked;
            Hashtable methodsBaked;
 
            if (!this.useLRE) {
                typBaked = this.typeBldr.CreateType(); 
 
                if (this.persistAsm) {
                    // Persist the assembly to disk 
                    ((AssemblyBuilder) this.typeBldr.Module.Assembly).Save(this.modFile + ".dll");
                }

                // Replace all MethodInfos in this.methods 
                methodsBaked = new Hashtable(this.methods.Count);
                foreach (string methName in this.methods.Keys) { 
                    methodsBaked[methName] = typBaked.GetMethod(methName, BindingFlags.NonPublic | BindingFlags.Static); 
                }
                this.methods = methodsBaked; 

                // Release TypeBuilder and symbol writer resources
                this.typeBldr = null;
                this.urlToSymWriter = null; 
            }
        } 
 
        /// 
        /// Wrap a delegate around a MethodInfo of the specified name and type and return it. 
        /// 
        public Delegate CreateDelegate(string name, Type typDelegate) {
            if (!this.useLRE)
                return Delegate.CreateDelegate(typDelegate, (MethodInfo) this.methods[name]); 

            return ((DynamicMethod) this.methods[name]).CreateDelegate(typDelegate); 
        } 

        ///  
        /// Define unique assembly name (within AppDomain).
        /// 
        private static AssemblyName CreateAssemblyName() {
            AssemblyName name; 

            System.Threading.Interlocked.Increment(ref AssemblyId); 
            name = new AssemblyName(); 
            name.Name = "System.Xml.Xsl.CompiledQuery." + AssemblyId;
 
            return name;
        }
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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XmlILModule.cs source code in C# .NET

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