Implement clipboard for Chromoting Linux hosts.

remoting/host/linux/x_server_clipboard.h

Index: remoting/host/linux/x_server_clipboard.h
diff --git a/remoting/host/linux/x_server_clipboard.h b/remoting/host/linux/x_server_clipboard.h
new file mode 100644
index 0000000000000000000000000000000000000000..3527a489c872cc0b2c789f8d75137f4b8265aa7c
--- /dev/null
+++ b/remoting/host/linux/x_server_clipboard.h
@@ -0,0 +1,104 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Don't include this file from any .h files because it pulls in some X headers.
+
+#ifndef REMOTING_HOST_LINUX_X_SERVER_CLIPBOARD_H_
+#define REMOTING_HOST_LINUX_X_SERVER_CLIPBOARD_H_
+
+#include <X11/Xatom.h>
+#include <X11/Xlib.h>
+
+#include <map>
+#include <set>
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/callback_forward.h"
+#include "base/timer.h"
+
+namespace remoting {
+
+// A class to allow manipulation of the X clipboard, using only X API calls.
+class XServerClipboard {
+ public:
+  typedef base::Callback<void(const std::string& mime_type,
+                              const std::string& data)>
+    ClipboardChangedCallback;
+
+  XServerClipboard();
+  ~XServerClipboard();
+
+  // The caller must ensure |display| is still valid whenever any other
+  // methods are called on this object.

[Wez, 2012/09/25 20:29:29]

nit: Start this comment with an explanation of what Init does, e.g. "Start
monitoring |display|'s selections and invoke |callback| whenever their content
changes." 

[Lambros, 2012/09/25 22:42:39]

Done.

+  void Init(Display* display, const ClipboardChangedCallback& callback);
+
+  // Copy data to the X Clipboard.  This acquires ownership of the
+  // PRIMARY and CLIPBOARD selections.
+  void SetClipboard(const std::string& mime_type, const std::string& data);
+
+  // This method allows this object to be hooked up to the program's main event
+  // loop.  It should be invoked by the caller for each X11 event.  This class

[Wez, 2012/09/25 20:29:29]

nit: Rephrase the comment to describe what this call does, e.g. "Process |event|
if it is an X selection notification. The caller must invoke this for every
event it receives from |display|".

[Lambros, 2012/09/25 22:42:39]

Done.

+  // is not thread-safe, so all its methods must be called on the application's
+  // main event-processing thread.

[Wez, 2012/09/25 20:29:29]

nit: Move the comment on the class' threading to the class comment rather than
this method.

[Lambros, 2012/09/25 22:42:39]

Done.

+  void ProcessXEvent(XEvent* event);
+
+ private:
+  void OnSetSelectionOwnerNotify(Atom selection, Time timestamp);
+  void OnPropertyNotify(XEvent* event);
+  void OnSelectionNotify(XEvent* event);
+  void OnSelectionRequest(XEvent* event);

[Wez, 2012/09/25 20:29:29]

Add a comment to this block of methods, e.g. "Handlers for X selection events."

[Lambros, 2012/09/25 22:42:39]

Done.

+
+  // Called when the selection owner has replied to a request for information
+  // about a selection.
+  void DoSelectionNotify(XSelectionEvent* event,
+                         Atom type,
+                         int format,
+                         int item_count,
+                         void* data);
+
+  bool HandleSelectionTargetsEvent(XSelectionEvent* event,
+                                   int format,
+                                   int item_count,
+                                   void* data);
+  bool HandleSelectionStringEvent(XSelectionEvent* event,
+                                  int format,
+                                  int item_count,
+                                  void* data);

[Wez, 2012/09/25 20:29:29]

Add a comment before these methods indicating that they return true if selection
processing is complete, false otherwise.

[Lambros, 2012/09/25 22:42:39]

Done.

+
+  // Notify the registered callback of new clipboard text.
+  void NotifyClipboardText(const std::string& text);
+
+  bool IsSelectionOwner(Atom selection);

[Wez, 2012/09/25 20:29:29]

nit: Move this near to AssertSelectionOwnership.

[Lambros, 2012/09/25 22:42:39]

Done.

+  void RequestSelectionTimestamp(Atom selection, Time time);

[Wez, 2012/09/25 20:29:29]

Add a comment before the Request* methods indicating that they trigger the X
server or selection owner to send us an event containing the requested
information.

[Wez, 2012/09/25 20:29:29]

nit: Remove RequestSelectionTimestamp?

[Lambros, 2012/09/25 22:42:39]

Done.

[Lambros, 2012/09/25 22:42:39]

Done.

+  void RequestSelectionTargets(Atom selection);
+  void RequestSelectionString(Atom selection, Atom target);
+
+  // Assert ownership of the specified |selection|.
+  void AssertSelectionOwnership(Atom selection);
+
+  Display* display_;
+  Window clipboard_window_;
+  bool have_xfixes_;
+  int xfixes_event_base_;
+  int xfixes_error_base_;
+  Atom clipboard_atom_;
+  Atom large_selection_atom_;
+  Atom selection_string_atom_;
+  Atom targets_atom_;
+  Atom timestamp_atom_;
+  Atom utf8_string_atom_;
+  std::set<Atom> selections_owned_;
+  std::map<Atom, Time> selection_own_time_;
+  std::string data_;
+  Atom large_selection_property_;
+  base::TimeTicks get_selections_time_;
+  ClipboardChangedCallback callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(XServerClipboard);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_LINUX_X_SERVER_CLIPBOARD_H_