xenadmin/XenAdmin/Core/Clip.cs

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/* Copyright (c) Citrix Systems Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms,
* with or without modification, are permitted provided
* that the following conditions are met:
*
* * Redistributions of source code must retain the above
* copyright notice, this list of conditions and the
* following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
using System;
using System.Runtime.InteropServices;
using System.Threading;
using System.Windows.Forms;
namespace XenAdmin.Core
{
class Clip
{
private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
internal static EventHandler ClipboardChanged = null;
internal static string ClipboardText = "";
private static IntPtr registeredClipboardHandle = IntPtr.Zero;
private static IntPtr nextClipboardViewer = IntPtr.Zero;
private static bool processingChangeCBChain = false;
private static bool processingDrawClipboard = false;
private static long lastDrawClipboard = 0L;
private static int drawClipboardCount = 0;
private static volatile bool GettingClipboard = false;
internal static void RegisterClipboardViewer()
{
Program.AssertOnEventThread();
UnregisterClipboardViewer();
// Register ourselves at the front of the chain.
Win32.SetLastError(0);
registeredClipboardHandle = Program.MainWindow.Handle;
nextClipboardViewer = Win32.SetClipboardViewer(registeredClipboardHandle);
int err = Marshal.GetLastWin32Error();
if (err != 0)
{
log.ErrorFormat("SetClipboardViewer failed with code {0}: {1}", err, Win32.GetMessageString((uint)err));
registeredClipboardHandle = IntPtr.Zero;
nextClipboardViewer = IntPtr.Zero;
return;
}
// Sanity check -- I can't see why this should ever happen, but xorg/cygwin checks.
if (nextClipboardViewer == Program.MainWindow.Handle)
{
log.Error("SetClipboardViewer has given us our Handle back!");
try
{
Win32.ChangeClipboardChain(registeredClipboardHandle, IntPtr.Zero);
}
catch (Exception exn)
{
log.WarnFormat("ChangeClipboardChain failed", exn);
}
registeredClipboardHandle = IntPtr.Zero;
nextClipboardViewer = IntPtr.Zero;
return;
}
StartGetClipboard();
}
internal static void UnregisterClipboardViewer()
{
if (registeredClipboardHandle != IntPtr.Zero)
{
// Remove existing registration from chain, if any.
Win32.SetLastError(0);
Win32.ChangeClipboardChain(registeredClipboardHandle, nextClipboardViewer);
int err = Marshal.GetLastWin32Error();
if (err != 0)
{
log.ErrorFormat("ChangeClipboardChain failed with code {0}: {1}", err, Win32.GetMessageString((uint)err));
}
registeredClipboardHandle = IntPtr.Zero;
nextClipboardViewer = IntPtr.Zero;
}
}
internal static void ProcessWMChangeCBChain(Message e)
{
Program.AssertOnEventThread();
if (!processingChangeCBChain)
{
processingChangeCBChain = true;
try
{
if (nextClipboardViewer == e.WParam)
{
// The handle being removed (WParam) is the one that we've got. We need to
// switch to the next handle in the chain (LParam).
nextClipboardViewer = e.LParam;
}
else
{
// Pass the message on -- it's not our link in the chain that is affected.
ForwardClipboardMessage(e);
}
}
finally
{
processingChangeCBChain = false;
}
}
}
internal static void ProcessWMDrawClipboard(Message e)
{
Program.AssertOnEventThread();
if (!processingDrawClipboard)
{
processingDrawClipboard = true;
try
{
// Windows XP Remote Desktop server is broken wrt the clipboard.
// If we receive 10 clipboard events in 500 msec then we move
// ourselves back to the front of the chain.
// Without this, we receive endless WM_DRAWCLIPBOARD events
// after disconnecting and reconnecting the RDP session.
long now = DateTime.Now.Ticks;
if (now - lastDrawClipboard > 5000000)
{
drawClipboardCount = 0;
lastDrawClipboard = now;
}
else
{
drawClipboardCount++;
if (drawClipboardCount > 10)
{
drawClipboardCount = 0;
lastDrawClipboard = now;
RegisterClipboardViewer();
}
}
StartGetClipboard();
ForwardClipboardMessage(e);
}
finally
{
processingDrawClipboard = false;
}
}
}
private static void ForwardClipboardMessage(Message e)
{
Program.AssertOnEventThread();
if (nextClipboardViewer == IntPtr.Zero)
return;
Win32.SetLastError(0);
Win32.SendMessage(nextClipboardViewer, e.Msg, e.WParam, e.LParam);
int err = Marshal.GetLastWin32Error();
if (err != 0)
{
log.ErrorFormat("SendMessage({0}) failed with code {1}: {2}",
Win32.GetWindowsMessageName(e.Msg), err, Win32.GetMessageString((uint)err));
}
}
private static void StartGetClipboard()
{
Program.AssertOnEventThread();
if (!GettingClipboard)
{
GettingClipboard = true;
Thread clipboardThread = new Thread(GetClipboard);
clipboardThread.SetApartmentState(ApartmentState.STA);
clipboardThread.IsBackground = true;
clipboardThread.Start();
}
}
private static void GetClipboard()
{
Program.AssertOffEventThread();
try
{
if (Clipboard.ContainsText())
{
string s = Clipboard.GetText();
if (s != ClipboardText)
{
ClipboardText = s;
Program.Invoke(Program.MainWindow, OnClipboardChanged);
}
}
}
catch
{
}
GettingClipboard = false;
}
private static void OnClipboardChanged()
{
Program.AssertOnEventThread();
if (ClipboardChanged != null)
ClipboardChanged(null, null);
}
}
}