Disk cache: Switch the disk cache to use the cache_thread....

net/disk_cache/file_posix.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.
 
 #include "net/disk_cache/file.h"
 
 #include <fcntl.h>
 
 #include <set>
 
@@ skipping 175 matching lines @@
 
 // ---------------------------------------------------------------------------
 
 void InFlightIO::PostRead(disk_cache::File *file, void* buf, size_t buf_len,
                           size_t offset, disk_cache::FileIOCallback *callback) {
   scoped_refptr<BackgroundIO> operation =
       new BackgroundIO(file, buf, buf_len, offset, callback, this);
   io_list_.insert(operation.get());
   file->AddRef();  // Balanced on InvokeCallback()
 
+  if (!callback_thread_)
+      callback_thread_ = MessageLoop::current();
+
   WorkerPool::PostTask(FROM_HERE,
                        NewRunnableMethod(operation.get(), &BackgroundIO::Read),
                        true);
 }
 
 void InFlightIO::PostWrite(disk_cache::File* file, const void* buf,
                            size_t buf_len, size_t offset,
                            disk_cache::FileIOCallback* callback,
                            bool delete_buffer) {
   scoped_refptr<BackgroundIO> operation =
       new BackgroundIO(file, buf, buf_len, offset, callback, this);
   io_list_.insert(operation.get());
   file->AddRef();  // Balanced on InvokeCallback()
 
+  if (!callback_thread_)
+    callback_thread_ = MessageLoop::current();
+
   WorkerPool::PostTask(FROM_HERE,
                        NewRunnableMethod(operation.get(), &BackgroundIO::Write,
                                          delete_buffer),
                        true);
 }
 
 void InFlightIO::WaitForPendingIO() {
   while (!io_list_.empty()) {
     // Block the current thread until all pending IO completes.
     IOList::iterator it = io_list_.begin();
     InvokeCallback(*it, true);
   }
+  // Unit tests can use different threads.
+  callback_thread_ = NULL;
 }
 
 // Runs on a worker thread.
 void InFlightIO::OnIOComplete(BackgroundIO* operation) {
   callback_thread_->PostTask(FROM_HERE,
                              NewRunnableMethod(operation,
                                                &BackgroundIO::OnIOSignalled));
   operation->io_completed()->Signal();
 }
 
@@ skipping 133 matching lines @@
 }
 
 size_t File::GetLength() {
   DCHECK(init_);
   size_t ret = lseek(platform_file_, 0, SEEK_END);
   return ret;
 }
 
 // Static.
 void File::WaitForPendingIO(int* num_pending_io) {
-  if (*num_pending_io)
-    Singleton<InFlightIO>::get()->WaitForPendingIO();
+  // We may be running unit tests so we should allow InFlightIO to reset the
+  // message loop.
+  Singleton<InFlightIO>::get()->WaitForPendingIO();
 }
 
 }  // namespace disk_cache