HttpCacheParams.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / xsp / System / Web / HttpCacheParams.cs / 1305376 / HttpCacheParams.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 * Cache Vary class.  Wraps Vary header 
 *
 * Copyright (c) 1998 Microsoft Corporation 
 */

namespace System.Web {
    using System.Text; 
    using System.Runtime.InteropServices;
    using System.Web.Util; 
    using System.Security.Permissions; 

 
    /// 
    ///    Indicates that a cache should contain multiple
    ///       representations for a particular Uri. This class is an encapsulation that
    ///       provides a rich, type-safe way to set the Vary header. 
    /// 
    public sealed class HttpCacheVaryByParams { 
        HttpDictionary  _parameters; 
        int             _ignoreParams;
        bool            _isModified; 
        bool            _paramsStar;

        public HttpCacheVaryByParams() {
            Reset(); 
        }
 
        internal void Reset() { 
            _isModified = false;
            _paramsStar = false; 
            _parameters = null;
            _ignoreParams = -1;
        }
 
        /*
         * Reset based on the cached vary headers. 
         */ 
        internal void ResetFromParams(String[] parameters) {
            int i, n; 

            Reset();
            if (parameters != null) {
                _isModified = true; 
                if (parameters[0].Length == 0) {
                    Debug.Assert(parameters.Length == 1, "parameters.Length == 1"); 
 
                    IgnoreParams = true;
                } 
                else if (parameters[0].Equals("*")) {
                    Debug.Assert(parameters.Length == 1, "parameters.Length == 1");

                    _paramsStar = true; 
                }
                else { 
                    _parameters = new HttpDictionary(); 
                    for (i = 0, n = parameters.Length; i < n; i++) {
                        _parameters.SetValue(parameters[i], parameters[i]); 
                    }
                }
            }
        } 

        internal bool IsModified() { 
            return _isModified; 
        }
 
        internal bool AcceptsParams() {
            return _ignoreParams == 1 || _paramsStar || _parameters != null;
        }
 
        internal String[] GetParams() {
            String[]    s = null; 
            Object      item; 
            int         i, j, c, n;
 
            if (_ignoreParams == 1) {
                s =  new String[1] {String.Empty};
            }
            else if (_paramsStar) { 
                s =  new String[1] {"*"};
            } 
            else if (_parameters != null) { 
                n = _parameters.Size;
                c = 0; 
                for (i = 0; i < n; i++) {
                    item = _parameters.GetValue(i);
                    if (item != null) {
                        c++; 
                    }
                } 
 
                if (c > 0) {
                    s = new string[c]; 
                    j = 0;
                    for (i = 0; i < n; i++) {
                        item = _parameters.GetValue(i);
                        if (item != null) { 
                            s[j] = (String) item;
                            j++; 
                        } 
                    }
 
                    Debug.Assert(j == c, "j == c");
                }
            }
 
            return s;
        } 
 
        //
        // Public methods and properties 
        //


        ///  
        ///     Default property.
        ///       Indexed property indicating that a cache should (or should not) vary according 
        ///       to a custom header. 
        /// 
        public bool this[String header] 
        {
            get {
                if (header == null) {
                    throw new ArgumentNullException("header"); 
                }
 
                if (header.Length == 0) { 
                    return _ignoreParams == 1;
                } 
                else {
                    return _paramsStar ||
                           (_parameters != null && _parameters.GetValue(header) != null);
                } 
            }
 
            set { 
                if (header == null) {
                    throw new ArgumentNullException("header"); 
                }

                if (header.Length == 0) {
                    IgnoreParams = value; 
                }
                /* 
                 * Since adding a Vary parameter is more restrictive, we don't 
                 * want components to be able to set a Vary parameter to false
                 * if another component has set it to true. 
                 */
                else if (value) {
                    _isModified = true;
                    _ignoreParams = 0; 
                    if (header.Equals("*")) {
                        _paramsStar = true; 
                        _parameters = null; 
                    }
                    else { 
                        // set value to header if true or null if false
                        if (!_paramsStar) {
                            if (_parameters == null) {
                                _parameters = new HttpDictionary(); 
                            }
 
                            _parameters.SetValue(header, header); 
                        }
                    } 
                }
            }
        }
 

        public bool IgnoreParams { 
            get { 
                return _ignoreParams == 1;
            } 

            set {
                // Don't ignore if params have been added
                if (_paramsStar || _parameters != null) { 
                    return;
                } 
 
                if (_ignoreParams == -1 || _ignoreParams == 1) {
                    _ignoreParams = value ? 1 : 0; 
                    _isModified = true;
                }
            }
        } 

        internal bool IsVaryByStar { 
            get { 
                return _paramsStar;
            } 
        }
    }
}

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

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