PageParserFilter.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / UI / PageParserFilter.cs / 2 / PageParserFilter.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 * Abstract class implemented by objects that need to control the parsing of pages. 
 *
 * Copyright (c) 2004 Microsoft Corporation 
 */
namespace System.Web.UI {

using System.Globalization; 
using System.Collections;
using System.Web.Configuration; 
using System.Web.Compilation; 
using System.Web.Util;
using System.Security.Permissions; 

[AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Medium)]
[AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Medium)]
public abstract class PageParserFilter { 

    private VirtualPath _virtualPath; 
    protected string VirtualPath { get { return _virtualPath.VirtualPathString; } } 

    // The current line number being parsed 
    private TemplateParser _parser;
    protected int Line { get { return _parser._lineNumber; } }

    private int _numberOfControlsAllowed; 
    private int _currentControlCount;
 
    private int _dependenciesAllowed; 
    private int _currentDependenciesCount;
 
    private int _directDependenciesAllowed;
    private int _currentDirectDependenciesCount;

    // Create a PageParserFilter and initialize it 
    internal static PageParserFilter Create(PagesSection pagesConfig, VirtualPath virtualPath, TemplateParser parser) {
        PageParserFilter pageParserFilter = pagesConfig.CreateControlTypeFilter(); 
        if (pageParserFilter != null) 
            pageParserFilter.InitializeInternal(virtualPath, parser);
 
        return pageParserFilter;
    }

    internal void InitializeInternal(VirtualPath virtualPath, TemplateParser parser) { 

        _parser = parser; 
        Debug.Assert(_virtualPath == null); 
        _virtualPath = virtualPath;
 
        Initialize();

        // Get the various limits we need to enforce
        _numberOfControlsAllowed = NumberOfControlsAllowed; 

        // Add 1 to these two, because internally we count the file itself as a 
        // dependency, but we don't want this to be reflected to the PageParserFilter 
        // implementor (VSWhidbey 341708)
        _dependenciesAllowed = TotalNumberOfDependenciesAllowed+1; 
        _directDependenciesAllowed = NumberOfDirectDependenciesAllowed+1;
    }

    // initialize the filter to be used for a specific page 
    protected virtual void Initialize() {
    } 
 
    // Informs the filter that the parsing of the page is complete
    public virtual void ParseComplete(ControlBuilder rootBuilder) { 
        Debug.Assert(_virtualPath != null);
    }

    // Allows the filter to return the compilation mode for the page. 
    // If it doesn't want to modify it, it can just return current.
    public virtual CompilationMode GetCompilationMode(CompilationMode current) { 
        return current; 
    }
 
    // Indicates whether code is allowed on the page.  This method allows
    // forbidding code even on pages that will be compiled (for perf)
    public virtual bool AllowCode {
        get { 
            return false;
        } 
    } 

    // Is the control Type allowed for this page 
    internal bool AllowControlInternal(Type controlType, ControlBuilder builder) {

        OnControlAdded();
 
        return AllowControl(controlType, builder);
    } 
 
    // Is the control Type allowed for this page
    public virtual bool AllowControl(Type controlType, ControlBuilder builder) { 
        return false;
    }

    // Is this base type allowed for this page 
    public virtual bool AllowBaseType(Type baseType) {
        return false; 
    } 

    internal bool AllowVirtualReference(CompilationSection compConfig, VirtualPath referenceVirtualPath) { 

        // Get the extension, and from it the type of the BuildProvider
        string extension = referenceVirtualPath.Extension;
        Type buildProviderType = CompilationUtil.GetBuildProviderTypeFromExtension( 
            compConfig, extension, BuildProviderAppliesTo.Web, false /*failIfUnknown*/);
 
        // If it's an unknown type, block it 
        if (buildProviderType == null)
            return false; 

        // Figure out the VirtualReferenceType based on the BuildProvider type
        VirtualReferenceType referenceType;
        if (buildProviderType == typeof(PageBuildProvider)) 
            referenceType = VirtualReferenceType.Page;
        else if (buildProviderType == typeof(UserControlBuildProvider)) 
            referenceType = VirtualReferenceType.UserControl; 
        else if (buildProviderType == typeof(MasterPageBuildProvider))
            referenceType = VirtualReferenceType.Master; 
        else if (buildProviderType == typeof(SourceFileBuildProvider))
            referenceType = VirtualReferenceType.SourceFile;
        else
            referenceType = VirtualReferenceType.Other; 

        return AllowVirtualReference(referenceVirtualPath.VirtualPathString, referenceType); 
    } 

    // Is the virtual path reference allowed in this page.  The referenceType 
    // indicates the type of references involved.
    public virtual bool AllowVirtualReference(string referenceVirtualPath, VirtualReferenceType referenceType) {
        return false;
    } 

    // Is the passed in server include () allowed 
    public virtual bool AllowServerSideInclude(string includeVirtualPath) { 
        return false;
    } 

    public virtual void PreprocessDirective(string directiveName, IDictionary attributes) { }

    public virtual int NumberOfControlsAllowed { 
        get {
            // By default, don't allow any 
            return 0; 
        }
    } 

    public virtual int TotalNumberOfDependenciesAllowed {
        get {
            // By default, don't allow any 
            return 0;
        } 
    } 

    public virtual int NumberOfDirectDependenciesAllowed { 
        get {
            // By default, don't allow any
            return 0;
        } 
    }
 
    private void OnControlAdded() { 

        // If it's negative, there is no limit 
        if (_numberOfControlsAllowed < 0)
            return;

        // Increase the control count 
        _currentControlCount++;
 
        // Fail if the limit has been reached 
        if (_currentControlCount > _numberOfControlsAllowed) {
            throw new HttpException(SR.GetString( 
                SR.Too_many_controls, _numberOfControlsAllowed.ToString(CultureInfo.CurrentCulture)));
        }
    }
 
    // Called by the parser when a file dependency (direct or indirect) is added
    internal void OnDependencyAdded() { 
 
        // If it's negative, there is no limit
        if (_dependenciesAllowed <= 0) 
            return;

        // Increase the dependency count
        _currentDependenciesCount++; 

        // Fail if the limit has been reached 
        if (_currentDependenciesCount > _dependenciesAllowed) { 
            throw new HttpException(SR.GetString(
                SR.Too_many_dependencies, VirtualPath, 
                _dependenciesAllowed.ToString(CultureInfo.CurrentCulture)));
        }
    }
 
    // Called by the parser when a direct file dependency is added
    internal void OnDirectDependencyAdded() { 
 
        // If it's negative, there is no limit
        if (_directDependenciesAllowed <= 0) 
            return;

        // Increase the direct dependency count
        _currentDirectDependenciesCount++; 

        // Fail if the limit has been reached 
        if (_currentDirectDependenciesCount > _directDependenciesAllowed) { 
            throw new HttpException(SR.GetString(
                SR.Too_many_direct_dependencies, VirtualPath, 
                _directDependenciesAllowed.ToString(CultureInfo.CurrentCulture)));
        }
    }
 
    // Give the filter a chance to process a code block.  If it returns true, the
    // code block is not processed further by the parser 
    public virtual bool ProcessCodeConstruct(CodeConstructType codeType, string code) { 
        return false;
    } 

    // Give the filter a chance to process a databinding attribute (e.g. Text=<%# expr %>)
    // If it returns true, the databinding attribute is not processed further by the parser
    public virtual bool ProcessDataBindingAttribute(string controlId, string name, string value) { 
        return false;
    } 
 
    // Give the filter a chance to process an event hookup (e.g. onclick="ClickHandler")
    // If it returns true, the event hookup is not processed further by the parser 
    public virtual bool ProcessEventHookup(string controlId, string eventName, string handlerName) {
        return false;
    }
 
    // Return the Type that should be used for NoCompile user controls
    public virtual Type GetNoCompileUserControlType() { 
        return null; 
    }
 
    // Add a ControlBuilder in the tree at the current parser position
    protected void AddControl(Type type, IDictionary attributes) {
        _parser.AddControl(type, attributes);
    } 

    // Set a property on the TemplateControl (Page/UserControl/Master) 
    protected void SetPageProperty(string filter, string name, string value) { 
        if (filter == null)
            filter = String.Empty; 

        _parser.RootBuilder.PreprocessAttribute(filter, name, value, true /*mainDirectiveMode*/);
    }
} 

// The type of reference passed to PageParserFilter.AllowVirtualReference 
public enum VirtualReferenceType { 
    Page,
    UserControl, 
    Master,
    SourceFile,
    Other
} 

// Used as parameter to the PageParserFilter.ProcessCodeConstruct API 
public enum CodeConstructType { 
    CodeSnippet,            // <% ... %>
    ExpressionSnippet,      // <%= ... %> 
    DataBindingSnippet,     // <%# ... %>
    ScriptTag               // 
}
}

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