net/disk_cache/blockfile/in_flight_io.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/disk_cache/blockfile/in_flight_io.h"
   6
   7 #include "base/bind.h"
   8 #include "base/location.h"
   9 #include "base/logging.h"
  10 #include "base/profiler/scoped_tracker.h"
  11 #include "base/single_thread_task_runner.h"
  12 #include "base/task_runner.h"
  13 #include "base/thread_task_runner_handle.h"
  14 #include "base/threading/thread_restrictions.h"
  15
  16 namespace disk_cache {
  17
  18 BackgroundIO::BackgroundIO(InFlightIO* controller)
  19     : result_(-1), io_completed_(true, false), controller_(controller) {
  20 }
  21
  22 // Runs on the primary thread.
  23 void BackgroundIO::OnIOSignalled() {
  24   if (controller_)
  25     controller_->InvokeCallback(this, false);
  26 }
  27
  28 void BackgroundIO::Cancel() {
  29   // controller_ may be in use from the background thread at this time.
  30   base::AutoLock lock(controller_lock_);
  31   DCHECK(controller_);
  32   controller_ = NULL;
  33 }
  34
  35 BackgroundIO::~BackgroundIO() {
  36 }
  37
  38 // ---------------------------------------------------------------------------
  39
  40 InFlightIO::InFlightIO()
  41     : callback_task_runner_(base::ThreadTaskRunnerHandle::Get()),
  42       running_(false),
  43       single_thread_(false) {
  44 }
  45
  46 InFlightIO::~InFlightIO() {
  47 }
  48
  49 // Runs on the background thread.
  50 void BackgroundIO::NotifyController() {
  51   base::AutoLock lock(controller_lock_);
  52   if (controller_)
  53     controller_->OnIOComplete(this);
  54 }
  55
  56 void InFlightIO::WaitForPendingIO() {
  57   while (!io_list_.empty()) {
  58     // Block the current thread until all pending IO completes.
  59     IOList::iterator it = io_list_.begin();
  60     InvokeCallback(it->get(), true);
  61   }
  62 }
  63
  64 void InFlightIO::DropPendingIO() {
  65   while (!io_list_.empty()) {
  66     IOList::iterator it = io_list_.begin();
  67     BackgroundIO* operation = it->get();
  68     operation->Cancel();
  69     DCHECK(io_list_.find(operation) != io_list_.end());
  70     io_list_.erase(make_scoped_refptr(operation));
  71   }
  72 }
  73
  74 // Runs on a background thread.
  75 void InFlightIO::OnIOComplete(BackgroundIO* operation) {
  76 #ifndef NDEBUG
  77   if (callback_task_runner_->RunsTasksOnCurrentThread()) {
  78     DCHECK(single_thread_ || !running_);
  79     single_thread_ = true;
  80   }
  81 #endif
  82
  83   callback_task_runner_->PostTask(
  84       FROM_HERE, base::Bind(&BackgroundIO::OnIOSignalled, operation));
  85   operation->io_completed()->Signal();
  86 }
  87
  88 // Runs on the primary thread.
  89 void InFlightIO::InvokeCallback(BackgroundIO* operation, bool cancel_task) {
  90   {
  91     // TODO(vadimt): Remove ScopedTracker below once crbug.com/422516 is fixed.
  92     tracked_objects::ScopedTracker tracking_profile(
  93         FROM_HERE_WITH_EXPLICIT_FUNCTION("422516 InFlightIO::InvokeCallback"));
  94
  95     // http://crbug.com/74623
  96     base::ThreadRestrictions::ScopedAllowWait allow_wait;
  97     operation->io_completed()->Wait();
  98   }
  99   running_ = true;
 100
 101   if (cancel_task)
 102     operation->Cancel();
 103
 104   // Make sure that we remove the operation from the list before invoking the
 105   // callback (so that a subsequent cancel does not invoke the callback again).
 106   DCHECK(io_list_.find(operation) != io_list_.end());
 107   DCHECK(!operation->HasOneRef());
 108   io_list_.erase(make_scoped_refptr(operation));
 109   OnOperationComplete(operation, cancel_task);
 110 }
 111
 112 // Runs on the primary thread.
 113 void InFlightIO::OnOperationPosted(BackgroundIO* operation) {
 114   DCHECK(callback_task_runner_->RunsTasksOnCurrentThread());
 115   io_list_.insert(make_scoped_refptr(operation));
 116 }
 117
 118 }  // namespace disk_cache