Mutual exclusion between gconf and the glib main loop.

net/proxy/proxy_config_service_linux.cc

 // Copyright (c) 2009 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 "net/proxy/proxy_config_service_linux.h"
 
 #include <gconf/gconf-client.h>
 #include <gdk/gdk.h>
 #include <stdlib.h>
 
+#include "base/lock.h"
 #include "base/logging.h"
+#include "base/message_pump_glib.h"
 #include "base/string_tokenizer.h"
 #include "base/string_util.h"
 #include "googleurl/src/url_canon.h"
 #include "net/base/net_errors.h"
 #include "net/http/http_util.h"
 #include "net/proxy/proxy_config.h"
 #include "net/proxy/proxy_server.h"
 
 namespace net {
 
@@ skipping 229 matching lines @@
 class GConfSettingGetterImpl
     : public ProxyConfigServiceLinux::GConfSettingGetter {
  public:
   GConfSettingGetterImpl() : client_(NULL) {}
   virtual ~GConfSettingGetterImpl() {
     if (client_)
       g_object_unref(client_);
   }
 
   virtual void Enter() {
-    gdk_threads_enter();
+    // Gconf is not thread-safe against itself, and it's meant to be
+    // used from the thread running the glib main loop. The proxy
+    // configuration is being fetched from the I/O thread, while the
+    // glib main loop runs in the UI thread. gconf has callbacks,
+    // timeouts and idles that will be dispatched from the glib main
+    // loop. We take this lock to enforce mutual exclusion with the
+    // glib main loop.
+    base::MessagePumpForUI::glib_main_loop_lock_.Acquire();
   }
   virtual void Leave() {
-    gdk_threads_leave();
+    base::MessagePumpForUI::glib_main_loop_lock_.Release();
   }
 
   virtual bool InitIfNeeded() {
     if (!client_) {
       Enter();
       client_ = gconf_client_get_default();
       Leave();
       // It's not clear whether/when this can return NULL.
       if (!client_)
         LOG(ERROR) << "ProxyConfigServiceLinux: Unable to create "
@@ skipping 272 matching lines @@
   if (!ok) {
     ok = GetConfigFromEnv(config);
     if (ok)
       LOG(INFO) << "ProxyConfigServiceLinux: obtained proxy setting "
           "from environment variables";
   }
   return ok ? OK : ERR_FAILED;
 }
 
 }  // namespace net