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