Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / MIT / System / Web / UI / MobileControls / SessionViewState.cs / 1305376 / SessionViewState.cs
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//-----------------------------------------------------------------------------
using System;
using System.Collections;
using System.Diagnostics;
using System.ComponentModel;
using System.Globalization;
using System.IO;
using System.Runtime.Serialization;
using System.Text;
using System.Web;
using System.Web.SessionState;
using System.Web.Util;
using System.Web.UI;
using System.Security.Permissions;
namespace System.Web.UI.MobileControls
{
/*
* Session-based view state.
*
* When saving view state on the server as session data, some critical problems
* arise. The core issue behind most of these is how to handle the user
* clicking the Back button. When the user does this, there is no corresponding
* notification to the server, and the client and server session state are thrown
* out of [....].
*
* This class attempts to alleviate this by storing a small history of view states
* in session data.
*
* To save session view state, construct a new object, set the ViewState and ActiveForm
* properties, and call Save. You'll get back a reference that contains the
* state reference to write out.
*
* To load session view state, construct a new object, and call Load. The class will
* attempt to construct the view state from its history.
*
* Copyright (c) 2000 Microsoft Corporation
*/
[Obsolete("The System.Web.Mobile.dll assembly has been deprecated and should no longer be used. For information about how to develop ASP.NET mobile applications, see http://go.microsoft.com/fwlink/?LinkId=157231.")]
internal class SessionViewState
{
private static readonly String ViewStateKey = "ViewState";
private Object _state;
internal SessionViewState() {
}
internal /*public*/ Object ViewState
{
get
{
return _state;
}
set
{
_state = value;
}
}
internal /*public*/ Pair Save(MobilePage page)
{
SessionViewStateHistory history = (SessionViewStateHistory)page.Session[ViewStateKey];
if (history == null)
{
history = new SessionViewStateHistory(HttpContext.Current);
page.Session[ViewStateKey] = history;
}
SessionViewStateHistoryItem historyItem = new SessionViewStateHistoryItem();
SaveTo(historyItem);
#if TRACE
historyItem.Url = page.Request.FilePath;
#endif
return history.Push(historyItem);
}
internal /*public*/ void Load(MobilePage page, Pair id)
{
_state = null;
SessionViewStateHistory history = (SessionViewStateHistory)page.Session[ViewStateKey];
if (history != null)
{
SessionViewStateHistoryItem historyItem = history.Find(id);
if (historyItem != null)
{
LoadFrom(historyItem);
}
}
}
private void SaveTo(SessionViewStateHistoryItem historyItem)
{
historyItem.ViewState = _state;
}
private void LoadFrom(SessionViewStateHistoryItem historyItem)
{
_state = historyItem.ViewState;
}
#if TRACE
internal /*public*/ void Dump(MobilePage page, out ArrayList arr)
{
SessionViewStateHistory history;
if ((page is IRequiresSessionState) && !(page is IReadOnlySessionState))
{
history = (SessionViewStateHistory)page.Session[ViewStateKey];
}
else
{
history = null;
}
if (history != null)
{
history.Dump(out arr);
}
else
{
arr = new ArrayList();
}
}
#endif
[
Serializable
]
private class SessionViewStateHistoryItem : ISerializable
{
#if TRACE
public String Url;
public String Id;
#endif
public Object ViewState;
public SessionViewStateHistoryItem()
{
}
public SessionViewStateHistoryItem(SerializationInfo info, StreamingContext context)
{
String s = (String)info.GetString("s");
if (s.Length > 0)
{
ViewState = new LosFormatter().Deserialize(s);
}
else
{
ViewState = null;
}
}
[SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter=true)]
void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
{
if (ViewState != null)
{
StringWriter s = new StringWriter(CultureInfo.InvariantCulture);
new LosFormatter().Serialize(s, ViewState);
info.AddValue("s", s.ToString());
}
else
{
info.AddValue("s", String.Empty);
}
}
}
// Session view state history. This is the history record kept in each session.
[
Serializable
]
private class SessionViewStateHistory
{
private int _historySize;
private SessionViewStateHistoryItem[] _history;
private int _currentHistoryIndex = 0;
private int _historyUsed = 0;
private DateTime _sessionUniqueID = DateTime.Now;
private int _currentHistoryID = 0;
public SessionViewStateHistory(HttpContext context)
{
_historySize = ControlsConfig.GetFromContext(context).SessionStateHistorySize;
if (_historySize < 1)
{
throw new Exception(
SR.GetString(SR.SessionViewState_InvalidSessionStateHistory));
}
_history = new SessionViewStateHistoryItem[_historySize];
}
public Pair Push(SessionViewStateHistoryItem item)
{
Pair id = new Pair(_sessionUniqueID, _currentHistoryID);
_currentHistoryID++;
_history[_currentHistoryIndex] = item;
_currentHistoryIndex = (_currentHistoryIndex + 1) % _historySize;
if (_historyUsed < _historySize)
{
_historyUsed++;
}
#if TRACE
item.Id = _currentHistoryID.ToString(CultureInfo.InvariantCulture);
#endif
return id;
}
public SessionViewStateHistoryItem Find(Pair id)
{
// First make sure that the page is from the current session.
DateTime uniqueID = (DateTime) id.First;
if (DateTime.Compare(uniqueID, _sessionUniqueID) != 0)
{
return null;
}
// Now check if we actually still have it.
int historyID = (int) id.Second;
int distance = _currentHistoryID - historyID;
if (distance <= 0)
{
// Shouldn't happen, but this would be a forward jump.
return null;
}
else if (distance > _historyUsed)
{
// Gone way back. Empty history, but return null.
_historyUsed = 0;
return null;
}
else
{
int foundIndex = (_currentHistoryIndex + _historySize - distance) %
_historySize;
// Make the found item the top of the stack.
_currentHistoryIndex = (foundIndex + 1) % _historySize;
_currentHistoryID = historyID + 1;
_historyUsed -= distance - 1;
return _history[foundIndex];
}
}
#if TRACE
public void Dump(out ArrayList arr)
{
arr = new ArrayList();
int n = _currentHistoryIndex;
for (int i = 0; i < _historyUsed; i++)
{
n = n - 1;
if (n == -1)
{
n = _history.Length - 1;
}
SessionViewStateHistoryItem item = _history[n];
if (item != null)
{
arr.Add(String.Format(CultureInfo.InvariantCulture, "{0}({1})", item.Url, item.Id));
}
else
{
arr.Add("(null)");
}
}
}
#endif
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//-----------------------------------------------------------------------------
using System;
using System.Collections;
using System.Diagnostics;
using System.ComponentModel;
using System.Globalization;
using System.IO;
using System.Runtime.Serialization;
using System.Text;
using System.Web;
using System.Web.SessionState;
using System.Web.Util;
using System.Web.UI;
using System.Security.Permissions;
namespace System.Web.UI.MobileControls
{
/*
* Session-based view state.
*
* When saving view state on the server as session data, some critical problems
* arise. The core issue behind most of these is how to handle the user
* clicking the Back button. When the user does this, there is no corresponding
* notification to the server, and the client and server session state are thrown
* out of [....].
*
* This class attempts to alleviate this by storing a small history of view states
* in session data.
*
* To save session view state, construct a new object, set the ViewState and ActiveForm
* properties, and call Save. You'll get back a reference that contains the
* state reference to write out.
*
* To load session view state, construct a new object, and call Load. The class will
* attempt to construct the view state from its history.
*
* Copyright (c) 2000 Microsoft Corporation
*/
[Obsolete("The System.Web.Mobile.dll assembly has been deprecated and should no longer be used. For information about how to develop ASP.NET mobile applications, see http://go.microsoft.com/fwlink/?LinkId=157231.")]
internal class SessionViewState
{
private static readonly String ViewStateKey = "ViewState";
private Object _state;
internal SessionViewState() {
}
internal /*public*/ Object ViewState
{
get
{
return _state;
}
set
{
_state = value;
}
}
internal /*public*/ Pair Save(MobilePage page)
{
SessionViewStateHistory history = (SessionViewStateHistory)page.Session[ViewStateKey];
if (history == null)
{
history = new SessionViewStateHistory(HttpContext.Current);
page.Session[ViewStateKey] = history;
}
SessionViewStateHistoryItem historyItem = new SessionViewStateHistoryItem();
SaveTo(historyItem);
#if TRACE
historyItem.Url = page.Request.FilePath;
#endif
return history.Push(historyItem);
}
internal /*public*/ void Load(MobilePage page, Pair id)
{
_state = null;
SessionViewStateHistory history = (SessionViewStateHistory)page.Session[ViewStateKey];
if (history != null)
{
SessionViewStateHistoryItem historyItem = history.Find(id);
if (historyItem != null)
{
LoadFrom(historyItem);
}
}
}
private void SaveTo(SessionViewStateHistoryItem historyItem)
{
historyItem.ViewState = _state;
}
private void LoadFrom(SessionViewStateHistoryItem historyItem)
{
_state = historyItem.ViewState;
}
#if TRACE
internal /*public*/ void Dump(MobilePage page, out ArrayList arr)
{
SessionViewStateHistory history;
if ((page is IRequiresSessionState) && !(page is IReadOnlySessionState))
{
history = (SessionViewStateHistory)page.Session[ViewStateKey];
}
else
{
history = null;
}
if (history != null)
{
history.Dump(out arr);
}
else
{
arr = new ArrayList();
}
}
#endif
[
Serializable
]
private class SessionViewStateHistoryItem : ISerializable
{
#if TRACE
public String Url;
public String Id;
#endif
public Object ViewState;
public SessionViewStateHistoryItem()
{
}
public SessionViewStateHistoryItem(SerializationInfo info, StreamingContext context)
{
String s = (String)info.GetString("s");
if (s.Length > 0)
{
ViewState = new LosFormatter().Deserialize(s);
}
else
{
ViewState = null;
}
}
[SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter=true)]
void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
{
if (ViewState != null)
{
StringWriter s = new StringWriter(CultureInfo.InvariantCulture);
new LosFormatter().Serialize(s, ViewState);
info.AddValue("s", s.ToString());
}
else
{
info.AddValue("s", String.Empty);
}
}
}
// Session view state history. This is the history record kept in each session.
[
Serializable
]
private class SessionViewStateHistory
{
private int _historySize;
private SessionViewStateHistoryItem[] _history;
private int _currentHistoryIndex = 0;
private int _historyUsed = 0;
private DateTime _sessionUniqueID = DateTime.Now;
private int _currentHistoryID = 0;
public SessionViewStateHistory(HttpContext context)
{
_historySize = ControlsConfig.GetFromContext(context).SessionStateHistorySize;
if (_historySize < 1)
{
throw new Exception(
SR.GetString(SR.SessionViewState_InvalidSessionStateHistory));
}
_history = new SessionViewStateHistoryItem[_historySize];
}
public Pair Push(SessionViewStateHistoryItem item)
{
Pair id = new Pair(_sessionUniqueID, _currentHistoryID);
_currentHistoryID++;
_history[_currentHistoryIndex] = item;
_currentHistoryIndex = (_currentHistoryIndex + 1) % _historySize;
if (_historyUsed < _historySize)
{
_historyUsed++;
}
#if TRACE
item.Id = _currentHistoryID.ToString(CultureInfo.InvariantCulture);
#endif
return id;
}
public SessionViewStateHistoryItem Find(Pair id)
{
// First make sure that the page is from the current session.
DateTime uniqueID = (DateTime) id.First;
if (DateTime.Compare(uniqueID, _sessionUniqueID) != 0)
{
return null;
}
// Now check if we actually still have it.
int historyID = (int) id.Second;
int distance = _currentHistoryID - historyID;
if (distance <= 0)
{
// Shouldn't happen, but this would be a forward jump.
return null;
}
else if (distance > _historyUsed)
{
// Gone way back. Empty history, but return null.
_historyUsed = 0;
return null;
}
else
{
int foundIndex = (_currentHistoryIndex + _historySize - distance) %
_historySize;
// Make the found item the top of the stack.
_currentHistoryIndex = (foundIndex + 1) % _historySize;
_currentHistoryID = historyID + 1;
_historyUsed -= distance - 1;
return _history[foundIndex];
}
}
#if TRACE
public void Dump(out ArrayList arr)
{
arr = new ArrayList();
int n = _currentHistoryIndex;
for (int i = 0; i < _historyUsed; i++)
{
n = n - 1;
if (n == -1)
{
n = _history.Length - 1;
}
SessionViewStateHistoryItem item = _history[n];
if (item != null)
{
arr.Add(String.Format(CultureInfo.InvariantCulture, "{0}({1})", item.Url, item.Id));
}
else
{
arr.Add("(null)");
}
}
}
#endif
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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