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//------------------------------------------------------------------------------
// <copyright file="httpapplicationstate.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
/*
* Application State Dictionary class
*
* Copyright (c) 1999 Microsoft Corporation
*/
namespace System.Web {
using System.Threading;
using System.Runtime.InteropServices;
using System.Security.Permissions;
using System.Collections;
using System.Collections.Specialized;
using System.Web;
using System.Web.Util;
//
// Application state collection
//
/// <devdoc>
/// <para>
/// The HttpApplicationState class enables developers to
/// share global information across multiple requests, sessions, and pipelines
/// within an ASP.NET application. (An ASP.NET application is the sum of all files, pages,
/// handlers, modules, and code
/// within the scope of a virtual directory and its
/// subdirectories on a single web server).
/// </para>
/// </devdoc>
public sealed class HttpApplicationState : NameObjectCollectionBase {
// app lock with auto-unlock feature
private HttpApplicationStateLock _lock = new HttpApplicationStateLock();
// static object collections
private HttpStaticObjectsCollection _applicationStaticObjects;
private HttpStaticObjectsCollection _sessionStaticObjects;
internal HttpApplicationState() : this(null, null) {
}
internal HttpApplicationState(HttpStaticObjectsCollection applicationStaticObjects,
HttpStaticObjectsCollection sessionStaticObjects)
: base(Misc.CaseInsensitiveInvariantKeyComparer) {
_applicationStaticObjects = applicationStaticObjects;
if (_applicationStaticObjects == null)
_applicationStaticObjects = new HttpStaticObjectsCollection();
_sessionStaticObjects = sessionStaticObjects;
if (_sessionStaticObjects == null)
_sessionStaticObjects = new HttpStaticObjectsCollection();
}
//
// Internal accessor to session static objects collection
//
internal HttpStaticObjectsCollection SessionStaticObjects {
get { return _sessionStaticObjects;}
}
//
// Implementation of standard collection stuff
//
/// <devdoc>
/// <para>Gets
/// the number of item objects in the application state collection.</para>
/// </devdoc>
public override int Count {
get {
int c = 0;
_lock.AcquireRead();
try {
c = base.Count;
}
finally {
_lock.ReleaseRead();
}
return c;
}
}
// modifying methods
/// <devdoc>
/// <para>
/// Adds
/// a new state object to the application state collection.
/// </para>
/// </devdoc>
public void Add(String name, Object value) {
_lock.AcquireWrite();
try {
BaseAdd(name, value);
}
finally {
_lock.ReleaseWrite();
}
}
/// <devdoc>
/// <para>Updates an HttpApplicationState value within the collection.</para>
/// </devdoc>
public void Set(String name, Object value) {
_lock.AcquireWrite();
try {
BaseSet(name, value);
}
finally {
_lock.ReleaseWrite();
}
}
/// <devdoc>
/// <para>Removes
/// an
/// object from the application state collection by name.</para>
/// </devdoc>
public void Remove(String name) {
_lock.AcquireWrite();
try {
BaseRemove(name);
}
finally {
_lock.ReleaseWrite();
}
}
/// <devdoc>
/// <para>Removes
/// an
/// object from the application state collection by name.</para>
/// </devdoc>
public void RemoveAt(int index) {
_lock.AcquireWrite();
try {
BaseRemoveAt(index);
}
finally {
_lock.ReleaseWrite();
}
}
/// <devdoc>
/// <para>
/// Removes
/// all objects from the application state collection.
/// </para>
/// </devdoc>
public void Clear() {
_lock.AcquireWrite();
try {
BaseClear();
}
finally {
_lock.ReleaseWrite();
}
}
/// <devdoc>
/// <para>
/// Removes
/// all objects from the application state collection.
/// </para>
/// </devdoc>
public void RemoveAll() {
Clear();
}
// access by key
/// <devdoc>
/// <para>
/// Enables user to retrieve application state object by name.
/// </para>
/// </devdoc>
public Object Get(String name) {
Object obj = null;
_lock.AcquireRead();
try {
obj = BaseGet(name);
}
finally {
_lock.ReleaseRead();
}
return obj;
}
/// <devdoc>
/// <para>Enables
/// a user to add/remove/update a single application state object.</para>
/// </devdoc>
public Object this[String name]
{
get { return Get(name);}
set { Set(name, value);}
}
// access by index
/// <devdoc>
/// <para>
/// Enables user
/// to retrieve a single application state object by index.
/// </para>
/// </devdoc>
public Object Get(int index) {
Object obj = null;
_lock.AcquireRead();
try {
obj = BaseGet(index);
}
finally {
_lock.ReleaseRead();
}
return obj;
}
/// <devdoc>
/// <para>
/// Enables user to retrieve an application state object name by index.
/// </para>
/// </devdoc>
public String GetKey(int index) {
String s = null;
_lock.AcquireRead();
try {
s = BaseGetKey(index);
}
finally {
_lock.ReleaseRead();
}
return s;
}
/// <devdoc>
/// <para>
/// Enables
/// user to retrieve an application state object by index.
/// </para>
/// </devdoc>
public Object this[int index]
{
get { return Get(index);}
}
// access to keys and values as arrays
/// <devdoc>
/// <para>
/// Enables user
/// to retrieve all application state object names in collection.
/// </para>
/// </devdoc>
public String[] AllKeys {
get {
String [] allKeys = null;
_lock.AcquireRead();
try {
allKeys = BaseGetAllKeys();
}
finally {
_lock.ReleaseRead();
}
return allKeys;
}
}
//
// Public properties
//
/// <devdoc>
/// <para>
/// Returns "this". Provided for legacy ASP compatibility.
/// </para>
/// </devdoc>
public HttpApplicationState Contents {
get { return this;}
}
/// <devdoc>
/// <para>
/// Exposes all objects declared via an <object
/// runat=server></object> tag within the ASP.NET application file.
/// </para>
/// </devdoc>
public HttpStaticObjectsCollection StaticObjects {
get { return _applicationStaticObjects;}
}
//
// Locking support
//
/// <devdoc>
/// <para>
/// Locks
/// access to all application state variables. Facilitates access
/// synchronization.
/// </para>
/// </devdoc>
public void Lock() {
_lock.AcquireWrite();
}
/// <devdoc>
/// <para>
/// Unocks access to all application state variables. Facilitates access
/// synchronization.
/// </para>
/// </devdoc>
public void UnLock() {
_lock.ReleaseWrite();
}
internal void EnsureUnLock() {
_lock.EnsureReleaseWrite();
}
}
//
// Recursive read-write lock that allows removing of all
// outstanding write locks from the current thread at once
//
internal class HttpApplicationStateLock : ReadWriteObjectLock {
private int _recursionCount;
private int _threadId;
internal HttpApplicationStateLock() {
}
internal override void AcquireRead() {
int currentThreadId = SafeNativeMethods.GetCurrentThreadId();
if (_threadId != currentThreadId)
base.AcquireRead(); // only if no write lock
}
internal override void ReleaseRead() {
int currentThreadId = SafeNativeMethods.GetCurrentThreadId();
if (_threadId != currentThreadId)
base.ReleaseRead(); // only if no write lock
}
internal override void AcquireWrite() {
int currentThreadId = SafeNativeMethods.GetCurrentThreadId();
if (_threadId == currentThreadId) {
_recursionCount++;
}
else {
base.AcquireWrite();
_threadId = currentThreadId;
_recursionCount = 1;
}
}
internal override void ReleaseWrite() {
int currentThreadId = SafeNativeMethods.GetCurrentThreadId();
if (_threadId == currentThreadId) {
if (--_recursionCount == 0) {
_threadId = 0;
base.ReleaseWrite();
}
}
}
//
// release all write locks held by the current thread
//
internal void EnsureReleaseWrite() {
int currentThreadId = SafeNativeMethods.GetCurrentThreadId();
if (_threadId == currentThreadId) {
_threadId = 0;
_recursionCount = 0;
base.ReleaseWrite();
}
}
}
}
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