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ui/base/x/x11_foreign_window_manager.cc

Index: ui/base/x/x11_foreign_window_manager.cc
diff --git a/ui/base/x/x11_foreign_window_manager.cc b/ui/base/x/x11_foreign_window_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a663c2d54359c46fbf76ee177e6a0de2f7b2e41d
--- /dev/null
+++ b/ui/base/x/x11_foreign_window_manager.cc
@@ -0,0 +1,74 @@
+// Copyright 2014 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.
+
+#include "ui/base/x/x11_foreign_window_manager.h"
+
+#include <X11/Xlib.h>
+
+#include "base/memory/singleton.h"
+
+namespace ui {
+
+// static
+XForeignWindowManager* XForeignWindowManager::GetInstance() {
+  return Singleton<XForeignWindowManager>::get();
+}
+
+int XForeignWindowManager::RequestEvents(XID xid, long event_mask) {
+  request_map_[xid].push_back(Request(next_request_id_, event_mask));
+  UpdateSelectedEvents(xid);
+  return next_request_id_++;
+}
+
+void XForeignWindowManager::CancelRequest(int request_id) {
+  for (std::map<XID, RequestList>::iterator map_it = request_map_.begin();
+       map_it != request_map_.end(); ++map_it) {
+    RequestList* list = &map_it->second;
+    for (RequestList::iterator list_it = list->begin();
+         list_it != list->end(); ++list_it) {
+      if (list_it->request_id == request_id) {
+        XID xid = map_it->first;
+
+        list->erase(list_it);
+        if (list->empty())
+          request_map_.erase(map_it);
+        UpdateSelectedEvents(xid);
+        return;
+      }
+    }
+  }
+}
+
+void XForeignWindowManager::OnWindowDestroyed(XID xid) {
+  request_map_.erase(xid);
+}
+
+XForeignWindowManager::XForeignWindowManager() : next_request_id_(0) {
+}
+
+XForeignWindowManager::~XForeignWindowManager() {
+}
+
+void XForeignWindowManager::UpdateSelectedEvents(XID xid) {
+  std::map<XID, RequestList>::iterator it = request_map_.find(xid);
+  if (it == request_map_.end())

[Daniel Erat, 2014/07/25 19:38:44]

i think there's a bug here. when removing the last request for an xid,
CancelRequest() deletes the xid's entry from |request_map_| before calling this
method. this method will then bail out here without unselecting the events,
won't it?

[pkotwicz, 2014/07/26 20:09:53]

You're right. Thanks for catching the bug!

+    return;
+
+  long event_mask = NoEventMask;
+  const RequestList& list = it->second;
+  for (size_t i = 0; i < list.size(); ++i)
+    event_mask |= list[i].event_mask;
+
+  XSelectInput(gfx::GetXDisplay(), xid, event_mask);

[Daniel Erat, 2014/07/25 19:38:44]

do we crash in response to X errors? i'm wondering if you need to trap errors
generated by this call in case the window is destroyed before your request makes
it to the X server.

[pkotwicz, 2014/07/26 20:09:53]

We do not crash. We just log errors via ui::LogErrorEventDescription().

This is a scenario I did not consider, thanks for pointing it out!
I am not adding a gfx::X11ErrorTracker to surpress the logging here. There are a
number of other places where we generate X errors if the X window is deleted.
The call to XChangeProperty() in ui::SelectionOwner::ProcessTarget() is an
example

+}
+
+XForeignWindowManager::Request::Request(int request_id, long event_mask)
+    : request_id(request_id),
+      event_mask(event_mask) {
+}
+
+XForeignWindowManager::Request::~Request() {
+}
+
+}  // namespace ui