Linux: Add xcb FD to glib event loop

ui/base/x/x11_window_cache_event_source.cc

+// Copyright 2016 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_window_cache_event_source.h"
+
+#include <glib.h>
+
+#include "base/logging.h"
+#include "ui/base/x/x11_window_cache.h"
+
+namespace ui {
+
+namespace {
+
+struct GLibXcbSource : public GSource {
+  GPollFD* poll_fd;
+};
+
+gboolean callback(gpointer data) {
+  XWindowCache* cache = reinterpret_cast<XWindowCache*>(data);
+  cache->OnConnectionReadable();
+  return !cache->ConnectionHasError();
+}
+
+gboolean prepare(GSource* source, gint* timeout) {
+  *timeout = -1;
+  return FALSE;
+}
+
+gboolean check(GSource* source) {
+  return static_cast<GLibXcbSource*>(source)->poll_fd->revents & G_IO_IN;
+}
+
+gboolean dispatch(GSource* source, GSourceFunc callback, gpointer data) {
+  return callback(data);
+}
+
+GSourceFuncs source_funcs {prepare, check, dispatch, nullptr};
+
+}  // anonymous namespace
+
+XWindowCacheEventSource::XWindowCacheEventSource(XWindowCache* cache) {
+  DCHECK(!cache->ConnectionHasError());
+  int fd = cache->ConnectionFd();
+
+  GPollFD* poll = new GPollFD();
+  g_poll_.reset(poll);
+  poll->fd = fd;
+  poll->events = G_IO_IN;
+  poll->revents = 0;
+
+  GLibXcbSource* g_source = static_cast<GLibXcbSource*>(
+      g_source_new(&source_funcs, sizeof(GLibXcbSource)));
+  g_source_ = g_source;
+  g_source->poll_fd = poll;
+  g_source_add_poll(g_source, poll);
+  g_source_set_can_recurse(g_source, TRUE);
+  g_source_set_callback(g_source, callback, cache, nullptr);
+  g_source_attach(g_source, g_main_context_default());
+}
+
+XWindowCacheEventSource::~XWindowCacheEventSource() {
+  g_source_destroy(g_source_);
+  g_source_unref(g_source_);
+}
+
+}  // namespace ui