ConfigurationPermission.cs source code in C# .NET

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

namespace System.Configuration { 
 
    using System.Security;
    using System.Security.Permissions; 
    using System.Globalization;

    [AttributeUsage(AttributeTargets.All, AllowMultiple=true, Inherited=false )]
    [Serializable] 
    sealed public class ConfigurationPermissionAttribute : CodeAccessSecurityAttribute
    { 
        public ConfigurationPermissionAttribute(SecurityAction action) : base(action) {} 

        public override IPermission CreatePermission() { 
            PermissionState state = (this.Unrestricted) ?
                    PermissionState.Unrestricted : PermissionState.None;

            return new ConfigurationPermission(state); 
        }
    } 
 
    //
    // ConfigurationPermission is used to grant access to configuration sections that 
    // would not otherwise be available if the caller attempted to read the configuration
    // files that make up configuration.
    //
    // The permission is a simple boolean one - it is either fully granted or denied. 
    // This boolean state is represented by using the PermissionState enumeration.
    // 
    [Serializable] 
    public sealed class ConfigurationPermission : CodeAccessPermission, IUnrestrictedPermission {
 
        private PermissionState _permissionState;  // Unrestricted or None

        //
        // Creates a new instance of ConfigurationPermission 
        // that passes all demands or that fails all demands.
        // 
        public ConfigurationPermission(PermissionState state) { 

            // validate state parameter 
            switch (state) {
            case PermissionState.Unrestricted:
            case PermissionState.None:
                _permissionState = state; 
                break;
 
            default: 
                throw ExceptionUtil.ParameterInvalid("state");
            } 
        }

        //
        // IUnrestrictedPermission interface methods 
        //
 
        // 
        // Checks the overall permission state of the object.
        // 
        public bool IsUnrestricted() {
            return _permissionState == PermissionState.Unrestricted;
        }
 
        //
        // Creates a copy. 
        // 
        public override IPermission Copy () {
            return new ConfigurationPermission(_permissionState); 
        }

        //
        // Returns the logical union between ConfigurationPermission instances. 
        //
        public override IPermission Union(IPermission target) { 
            if (target == null) { 
                return Copy();
            } 

            if (target.GetType() !=  typeof(ConfigurationPermission)) {
                throw ExceptionUtil.ParameterInvalid("target");
            } 

            // Create an Unrestricted permission if either this or other is unrestricted 
            if (_permissionState == PermissionState.Unrestricted) { 
                return new ConfigurationPermission(PermissionState.Unrestricted);
            } 
            else {
                ConfigurationPermission other = (ConfigurationPermission) target;
                return new ConfigurationPermission(other._permissionState);
            } 
        }
 
        // 
        // Returns the logical intersection between two ConfigurationPermission instances.
        // 
        public override IPermission Intersect(IPermission target) {
            if (target == null) {
                return null;
            } 

            if (target.GetType() !=  typeof(ConfigurationPermission)) { 
                throw ExceptionUtil.ParameterInvalid("target"); 
            }
 
            // Create an None permission if either this or other is None
            if (_permissionState == PermissionState.None) {
                return new ConfigurationPermission(PermissionState.None);
            } 
            else {
                ConfigurationPermission other = (ConfigurationPermission) target; 
                return new ConfigurationPermission(other._permissionState); 
            }
        } 

        //
        // Compares two ConfigurationPermission instances
        // 
        public override bool IsSubsetOf(IPermission target) {
            if (target == null) { 
                return _permissionState == PermissionState.None; 
            }
 
            if (target.GetType() != typeof(ConfigurationPermission)) {
                throw ExceptionUtil.ParameterInvalid("target");
            }
 
            ConfigurationPermission other = (ConfigurationPermission) target;
            return (_permissionState == PermissionState.None || other._permissionState == PermissionState.Unrestricted); 
        } 

        public override void FromXml(SecurityElement securityElement) { 
            if (securityElement == null) {
                throw new ArgumentNullException(SR.GetString(SR.ConfigurationPermissionBadXml,"securityElement"));
            }
 
            if (!securityElement.Tag.Equals("IPermission")) {
                throw new ArgumentException(SR.GetString(SR.ConfigurationPermissionBadXml,"securityElement")); 
            } 

            string className = securityElement.Attribute("class"); 
            if (className == null) {
                throw new ArgumentException(SR.GetString(SR.ConfigurationPermissionBadXml,"securityElement"));
            }
 
            if (className.IndexOf(this.GetType().FullName, StringComparison.Ordinal ) < 0) {
                throw new ArgumentException(SR.GetString(SR.ConfigurationPermissionBadXml,"securityElement")); 
            } 

            string version = securityElement.Attribute("version"); 
            if (version != "1") {
                throw new ArgumentException(SR.GetString(SR.ConfigurationPermissionBadXml,"version"));
            }
 
            string unrestricted = securityElement.Attribute("Unrestricted");
            if (unrestricted == null) { 
                _permissionState = PermissionState.None; 
            }
            else { 
                switch (unrestricted) {
                    case "true":
                        _permissionState = PermissionState.Unrestricted;
                        break; 

                    case "false": 
                        _permissionState = PermissionState.None; 
                        break;
 
                    default:
                        throw new ArgumentException(SR.GetString(SR.ConfigurationPermissionBadXml,"Unrestricted"));
                }
            } 
        }
 
        public override SecurityElement ToXml() { 
            SecurityElement securityElement = new SecurityElement("IPermission");
            securityElement.AddAttribute("class", this.GetType().FullName + ", " + this.GetType().Module.Assembly.FullName.Replace( '\"', '\'' )); 
            securityElement.AddAttribute("version", "1");
            if (IsUnrestricted()) {
                securityElement.AddAttribute("Unrestricted", "true");
            } 

            return securityElement; 
        } 
    }
} 


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

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