//------------------------------------------------------------------------------
// <copyright file="BaseParser.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>                                                                
//------------------------------------------------------------------------------

/*
 * Implements the ASP.NET template parser
 *
 * Copyright (c) 1998 Microsoft Corporation
 */

/*********************************

Class hierarchy

BaseParser
    DependencyParser
        TemplateControlDependencyParser
            PageDependencyParser
            UserControlDependencyParser
            MasterPageDependencyParser
    TemplateParser
        BaseTemplateParser
            TemplateControlParser
                PageParser
                UserControlParser
                    MasterPageParser
            PageThemeParser
        ApplicationFileParser

**********************************/

namespace System.Web.UI {
using System;
using System.Collections;
using System.Reflection;
using System.Web.Compilation;
using System.Web.Hosting;
using System.Web.Util;
using System.Text.RegularExpressions;
using System.Web.RegularExpressions;
using System.Security.Permissions;

// Internal interface for Parser that have exteranl assembly dependency.
internal interface IAssemblyDependencyParser {
    ICollection AssemblyDependencies { get; }
}


/// <devdoc>
///    <para>[To be supplied.]</para>
/// </devdoc>
public class BaseParser {

    // The directory used for relative path calculations
    private VirtualPath _baseVirtualDir;
    internal VirtualPath BaseVirtualDir {
        get { return _baseVirtualDir; }

    }

    // The virtual path to the file currently being processed
    private VirtualPath _currentVirtualPath;
    internal VirtualPath CurrentVirtualPath {
        get { return _currentVirtualPath; }
        set {
            _currentVirtualPath = value;

            // Can happen in the designer
            if (value == null) return;

            _baseVirtualDir = value.Parent;
        }
    }

    internal string CurrentVirtualPathString {
        get { return System.Web.VirtualPath.GetVirtualPathString(CurrentVirtualPath); }
    }

    private Regex _tagRegex;
    // The 3.5 regex is used only when targeting 2.0/3.5 for backward compatibility (Dev10 bug 830783).
    private readonly static Regex tagRegex35 = new TagRegex35();
    // The 4.0 regex is used for web sites targeting 4.0 and above. 
    private readonly static Regex tagRegex40 = new TagRegex();

    internal readonly static Regex directiveRegex = new DirectiveRegex();
    internal readonly static Regex endtagRegex = new EndTagRegex();
    internal readonly static Regex aspCodeRegex = new AspCodeRegex();
    internal readonly static Regex aspExprRegex = new AspExprRegex();
    internal readonly static Regex aspEncodedExprRegex = new AspEncodedExprRegex();
    internal readonly static Regex databindExprRegex = new DatabindExprRegex();
    internal readonly static Regex commentRegex = new CommentRegex();
    internal readonly static Regex includeRegex = new IncludeRegex();
    internal readonly static Regex textRegex = new TextRegex();

    // Regexes used in DetectSpecialServerTagError
    internal readonly static Regex gtRegex = new GTRegex();
    internal readonly static Regex ltRegex = new LTRegex();
    internal readonly static Regex serverTagsRegex = new ServerTagsRegex();
    internal readonly static Regex runatServerRegex = new RunatServerRegex();

    /*
     * Turns relative virtual path into absolute ones
     */
    internal VirtualPath ResolveVirtualPath(VirtualPath virtualPath) {
        return VirtualPathProvider.CombineVirtualPathsInternal(CurrentVirtualPath, virtualPath);
    }

    private bool IsVersion40OrAbove() {
        if (HostingEnvironment.IsHosted) {
            // If we are running in a hosted environment, then we can simply check the target version.
            return MultiTargetingUtil.IsTargetFramework40OrAbove;
        }
        else {
            // Otherwise, we are in the designer, and thus should check using the type description provider.
            // The new type TagRegex35 only exists when targeting 4.0 and above.
            return TargetFrameworkUtil.IsSupportedType(typeof(TagRegex35));
        }
    }

    internal Regex TagRegex {
        get {
            if (_tagRegex == null) {
                _tagRegex = IsVersion40OrAbove() ? tagRegex40 : tagRegex35;
            }
            return _tagRegex;
        }
    }
}


}