remoting/host/linux/x11_util.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef REMOTING_HOST_LINUX_X11_UTIL_H_
   6 #define REMOTING_HOST_LINUX_X11_UTIL_H_
   7
   8 // Xlib.h defines XErrorEvent as an anonymous struct, so we can't forward-
   9 // declare it in this header. Since Xlib.h is not generally something you
  10 // should #include into arbitrary code, please refrain from #including this
  11 // header in another header.
  12 #include <X11/Xlib.h>
  13
  14 #include "base/callback.h"
  15
  16 namespace remoting {
  17
  18 // Temporarily install an alternative handler for X errors. The default handler
  19 // exits the process, which is not what we want.
  20 //
  21 // Note that X error handlers are global, which means that this class is not
  22 // thread safe.
  23 class ScopedXErrorHandler {
  24  public:
  25   typedef base::Callback<void(Display*, XErrorEvent*)> Handler;
  26
  27   explicit ScopedXErrorHandler(const Handler& handler);
  28   ~ScopedXErrorHandler();
  29
  30   // Return false if any X errors have been encountered in the scope of this
  31   // handler.
  32   bool ok() const { return ok_; }
  33
  34   // Basic handler that ignores X errors.
  35   static Handler Ignore();
  36
  37  private:
  38   static int HandleXErrors(Display* display, XErrorEvent* error);
  39
  40   Handler handler_;
  41   int (*previous_handler_)(Display*, XErrorEvent*);
  42   bool ok_;
  43
  44   DISALLOW_COPY_AND_ASSIGN(ScopedXErrorHandler);
  45 };
  46
  47
  48 // Grab/release the X server within a scope. This can help avoid race
  49 // conditions that would otherwise lead to X errors.
  50 class ScopedXGrabServer {
  51  public:
  52   ScopedXGrabServer(Display* display);
  53   ~ScopedXGrabServer();
  54
  55  private:
  56   Display* display_;
  57
  58   DISALLOW_COPY_AND_ASSIGN(ScopedXGrabServer);
  59 };
  60
  61 }  // namespace remoting
  62
  63 #endif  // REMOTING_HOST_LINUX_X11_UTIL_H_