Add files to browser/sync.

chrome/browser/sync/glue/bookmark_model_worker.cc

+// Copyright (c) 2006-2008 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.
+
+#ifdef CHROME_PERSONALIZATION
+
+#include "chrome/browser/sync/glue/bookmark_model_worker.h"
+
+#include "base/message_loop.h"
+#include "base/waitable_event.h"
+
+namespace browser_sync {
+
+void BookmarkModelWorker::CallDoWorkFromModelSafeThreadAndWait(
+    ModelSafeWorkerInterface::Visitor* visitor) {
+  // It is possible this gets called when we are in the STOPPING state, because
+  // the UI loop has initiated shutdown but the syncer hasn't got the memo yet.
+  // This is fine, the work will get scheduled and run normally or run by our
+  // code handling this case in Stop().
+  DCHECK_NE(state_, STOPPED);
+  if (state_ == STOPPED)
+    return;
+  if (MessageLoop::current() == bookmark_model_loop_) {
+    DLOG(WARNING) << "CallDoWorkFromModelSafeThreadAndWait called from "
+      << "bookmark_model_loop_. Probably a nested invocation?";
+    visitor->DoWork();
+    return;
+  }
+
+  // Create an unsignaled event to wait on.
+  base::WaitableEvent work_done(false, false);
+  {
+    // We lock only to avoid PostTask'ing a NULL pending_work_ (because it
+    // could get Run() in Stop() and call OnTaskCompleted before we post).
+    // The task is owned by the message loop as per usual.
+    AutoLock lock(pending_work_lock_);
+    DCHECK(!pending_work_);
+    pending_work_ = new CallDoWorkAndSignalTask(visitor, &work_done, this);
+    bookmark_model_loop_->PostTask(FROM_HERE, pending_work_);
+  }
+  syncapi_event_.Signal();  // Notify that the syncapi produced work for us.
+  work_done.Wait();
+}
+
+BookmarkModelWorker::~BookmarkModelWorker() {
+  DCHECK_EQ(state_, STOPPED);
+}
+
+void BookmarkModelWorker::OnSyncerShutdownComplete() {
+  // The SyncerThread has terminated and we are no longer needed by syncapi.
+  // The UI loop initiated shutdown and is (or will be) waiting in Stop().
+  // We could either be WORKING or RUNNING_MANUAL_SHUTDOWN_PUMP, depending
+  // on where we timeslice the UI thread in Stop; but we can't be STOPPED,
+  // because that would imply NotifySyncapiShutdownComplete already signaled.
+  DCHECK_NE(state_, STOPPED);
+
+  syncapi_has_shutdown_ = true;
+  syncapi_event_.Signal();
+}
+
+void BookmarkModelWorker::Stop() {
+  DCHECK_EQ(MessageLoop::current(), bookmark_model_loop_);
+  DCHECK_EQ(state_, WORKING);
+
+  // We're on our own now, the beloved UI MessageLoop is no longer running.
+  // Any tasks scheduled or to be scheduled on the UI MessageLoop will not run.
+  state_ = RUNNING_MANUAL_SHUTDOWN_PUMP;
+
+  // Drain any final task manually until the SyncerThread tells us it has
+  // totally finished. Note we use a 'while' loop and not 'if'. The main subtle
+  // reason for this is that syncapi_event could be signaled the first time we
+  // come through due to an old CallDoWork call, and we need to keep looping
+  // until the SyncerThread either calls it again or tells us it is done. There
+  // should only ever be 0 or 1 tasks Run() here, however.
+  while (!syncapi_has_shutdown_) {
+    {
+      AutoLock lock(pending_work_lock_);
+      if (pending_work_)
+        pending_work_->Run();
+    }
+    syncapi_event_.Wait();  // Signaled either by new task, or SyncerThread
+                            // termination.
+  }
+
+  state_ = STOPPED;
+}
+
+void BookmarkModelWorker::CallDoWorkAndSignalTask::Run() {
+  if (!visitor_) {
+    // This can happen during tests or cases where there are more than just the
+    // default BookmarkModelWorker in existence and it gets destroyed before
+    // the main UI loop has terminated.  There is no easy way to assert the
+    // loop is running / not running at the moment, so we just provide cancel
+    // semantics here and short-circuit.
+    // TODO(timsteele): Maybe we should have the message loop destruction
+    // observer fire when the loop has ended, just a bit before it
+    // actually gets destroyed.
+    return;
+  }
+  visitor_->DoWork();
+
+  // Sever ties with visitor_ to allow the sanity-checking above that we don't
+  // get run twice.
+  visitor_ = NULL;
+
+  // Notify the BookmarkModelWorker that scheduled us that we have run
+  // successfully.
+  scheduler_->OnTaskCompleted();
+  work_done_->Signal();  // Unblock the syncer thread that scheduled us.
+}
+
+}  // namespace browser_sync
+
+#endif  // CHROME_PERSONALIZATION