Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/Compilation/ExpressionBuilder.cs

@@ -0,0 +1,119 @@
+//------------------------------------------------------------------------------
+// <copyright file="ExpressionBuilder.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Web.Compilation {
+    using System;
+    using System.CodeDom;
+    using System.Collections;
+    using System.Collections.Specialized;
+    using System.ComponentModel.Design;
+    using System.Web.Configuration;
+    using System.Reflection;
+    using System.Web;
+    using System.Web.Hosting;
+#if !FEATURE_PAL
+    using System.Web.UI.Design;
+#endif // !FEATURE_PAL
+    using System.Web.UI;
+    using System.Web.Util;
+
+
+    public abstract class ExpressionBuilder {
+        private static ExpressionBuilder dataBindingExpressionBuilder;
+
+        internal virtual void BuildExpression(BoundPropertyEntry bpe, ControlBuilder controlBuilder,
+            CodeExpression controlReference, CodeStatementCollection methodStatements, CodeStatementCollection statements, CodeLinePragma linePragma, ref bool hasTempObject) {
+
+            CodeExpression codeExpression = GetCodeExpression(bpe,
+                bpe.ParsedExpressionData, new ExpressionBuilderContext(controlBuilder.VirtualPath));
+
+            CodeDomUtility.CreatePropertySetStatements(methodStatements, statements,
+                controlReference, bpe.Name, bpe.Type,
+                codeExpression,
+                linePragma);
+        }
+
+        internal static ExpressionBuilder GetExpressionBuilder(string expressionPrefix, VirtualPath virtualPath) {
+            return GetExpressionBuilder(expressionPrefix, virtualPath, null);
+        }
+
+        internal static ExpressionBuilder GetExpressionBuilder(string expressionPrefix, VirtualPath virtualPath, IDesignerHost host) {
+            // If there is no expressionPrefix, it's a v1 style databinding expression
+            if (expressionPrefix.Length == 0) {
+                if (dataBindingExpressionBuilder == null) {
+                    dataBindingExpressionBuilder = new DataBindingExpressionBuilder();
+                }
+                return dataBindingExpressionBuilder;
+            }
+
+            CompilationSection config = null;
+
+            // If we are in the designer, we need to access IWebApplication config instead
+#if !FEATURE_PAL // FEATURE_PAL does not support designer-based features
+            if (host != null) {
+                IWebApplication webapp = (IWebApplication)host.GetService(typeof(IWebApplication));
+                if (webapp != null) {
+                    config = webapp.OpenWebConfiguration(true).GetSection("system.web/compilation") as CompilationSection;
+                }
+            }
+#endif // !FEATURE_PAL
+
+            // If we failed to get config from the designer, fall back on runtime config always
+            if (config == null) {
+                config = MTConfigUtil.GetCompilationConfig(virtualPath);
+            }
+
+            System.Web.Configuration.ExpressionBuilder builder = config.ExpressionBuilders[expressionPrefix];
+            if (builder == null) {
+                throw new HttpParseException(SR.GetString(SR.InvalidExpressionPrefix, expressionPrefix));
+            }
+
+            Type expressionBuilderType = null;
+            if (host != null) {
+                // If we are in the designer, we have to use the type resolution service
+                ITypeResolutionService ts = (ITypeResolutionService)host.GetService(typeof(ITypeResolutionService));
+                if (ts != null) {
+                    expressionBuilderType = ts.GetType(builder.Type);
+                }
+            }
+            if (expressionBuilderType == null) {
+                expressionBuilderType = builder.TypeInternal;
+            }
+            Debug.Assert(expressionBuilderType != null, "expressionBuilderType should not be null");
+
+            if (!typeof(ExpressionBuilder).IsAssignableFrom(expressionBuilderType)) {
+                throw new HttpParseException(SR.GetString(SR.ExpressionBuilder_InvalidType, expressionBuilderType.FullName));
+            }
+            ExpressionBuilder expressionBuilder = (ExpressionBuilder)HttpRuntime.FastCreatePublicInstance(expressionBuilderType);
+
+            return expressionBuilder;
+        }
+
+        //
+        // Public API
+        //
+
+        public virtual bool SupportsEvaluate {
+            get {
+                return false;
+            }
+        }
+
+        public virtual object ParseExpression(string expression, Type propertyType, ExpressionBuilderContext context) {
+            return null;
+        }
+
+
+        public abstract CodeExpression GetCodeExpression(BoundPropertyEntry entry,
+            object parsedData, ExpressionBuilderContext context);
+
+        public virtual object EvaluateExpression(object target, BoundPropertyEntry entry, 
+            object parsedData, ExpressionBuilderContext context) {
+            return null;
+        }
+
+    }
+}