Merge 243495 "Disk Cache: Use the old WorkerPool for Async IO on..."

> Disk Cache: Use the old WorkerPool for Async IO on iOS.
> 
> This basically reverts r222408 for iOS
> 
> BUG=330074
> TEST=net_unittests
> 
> Review URL: https://codereview.chromium.org/103533012

TBR=rvargas@chromium.org

Review URL: https://codereview.chromium.org/137483004

git-svn-id: svn://svn.chromium.org/chrome/branches/1750/src@244964 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 335 insertions, 1 deletions

diff --git a/net/disk_cache/backend_impl.cc b/net/disk_cache/backend_impl.cc
index a3250ff..9e21317 100644
--- a/net/disk_cache/backend_impl.cc
+++ b/net/disk_cache/backend_impl.cc
@@ -305,6 +305,8 @@ void BackendImpl::CleanupCache() {
       // This is a net_unittest, verify that we are not 'leaking' entries.
       File::WaitForPendingIO(&num_pending_io_);
       DCHECK(!num_refs_);
+    } else {
+      File::DropPendingIO();
     }
   }
   block_files_.CloseFiles();
diff --git a/net/disk_cache/backend_unittest.cc b/net/disk_cache/backend_unittest.cc
index b25001f..f3c02fd 100644
--- a/net/disk_cache/backend_unittest.cc
+++ b/net/disk_cache/backend_unittest.cc
@@ -518,9 +518,13 @@ void DiskCacheBackendTest::BackendShutdownWithPendingFileIO(bool fast) {
 
   base::MessageLoop::current()->RunUntilIdle();
 
+#if !defined(OS_IOS)
   // Wait for the actual operation to complete, or we'll keep a file handle that
-  // may cause issues later.
+  // may cause issues later. Note that on iOS systems even though this test
+  // uses a single thread, the actual IO is posted to a worker thread and the
+  // cache destructor breaks the link to reach cb when the operation completes.
   rv = cb.GetResult(rv);
+#endif
 }
 
 TEST_F(DiskCacheBackendTest, ShutdownWithPendingFileIO) {
@@ -543,6 +547,8 @@ TEST_F(DiskCacheBackendTest, ShutdownWithPendingFileIO_Fast) {
 }
 #endif
 
+// See crbug.com/330074
+#if !defined(OS_IOS)
 // Tests that one cache instance is not affected by another one going away.
 TEST_F(DiskCacheBackendTest, MultipleInstancesWithPendingFileIO) {
   base::ScopedTempDir store;
@@ -576,6 +582,7 @@ TEST_F(DiskCacheBackendTest, MultipleInstancesWithPendingFileIO) {
   // may cause issues later.
   rv = cb.GetResult(rv);
 }
+#endif
 
 // Tests that we deal with background-thread pending operations.
 void DiskCacheBackendTest::BackendShutdownWithPendingIO(bool fast) {
diff --git a/net/disk_cache/file.h b/net/disk_cache/file.h
index eb9a9ec..190f7cb 100644
--- a/net/disk_cache/file.h
+++ b/net/disk_cache/file.h
@@ -70,6 +70,9 @@ class NET_EXPORT_PRIVATE File : public base::RefCounted<File> {
   // Blocks until |num_pending_io| IO operations complete.
   static void WaitForPendingIO(int* num_pending_io);
 
+  // Drops current pending operations without waiting for them to complete.
+  static void DropPendingIO();
+
  protected:
   virtual ~File();
 
diff --git a/net/disk_cache/file_ios.cc b/net/disk_cache/file_ios.cc
new file mode 100644
index 0000000..9cad155
--- /dev/null
+++ b/net/disk_cache/file_ios.cc
@@ -0,0 +1,312 @@
+// Copyright 2014 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 "base/bind.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/threading/worker_pool.h"
+#include "net/base/net_errors.h"
+#include "net/disk_cache/disk_cache.h"
+#include "net/disk_cache/in_flight_io.h"
+
+namespace {
+
+// This class represents a single asynchronous IO operation while it is being
+// bounced between threads.
+class FileBackgroundIO : public disk_cache::BackgroundIO {
+ public:
+  // Other than the actual parameters for the IO operation (including the
+  // |callback| that must be notified at the end), we need the controller that
+  // is keeping track of all operations. When done, we notify the controller
+  // (we do NOT invoke the callback), in the worker thead that completed the
+  // operation.
+  FileBackgroundIO(disk_cache::File* file, const void* buf, size_t buf_len,
+                   size_t offset, disk_cache::FileIOCallback* callback,
+                   disk_cache::InFlightIO* controller)
+      : disk_cache::BackgroundIO(controller), callback_(callback), file_(file),
+        buf_(buf), buf_len_(buf_len), offset_(offset) {
+  }
+
+  disk_cache::FileIOCallback* callback() {
+    return callback_;
+  }
+
+  disk_cache::File* file() {
+    return file_;
+  }
+
+  // Read and Write are the operations that can be performed asynchronously.
+  // The actual parameters for the operation are setup in the constructor of
+  // the object. Both methods should be called from a worker thread, by posting
+  // a task to the WorkerPool (they are RunnableMethods). When finished,
+  // controller->OnIOComplete() is called.
+  void Read();
+  void Write();
+
+ private:
+  virtual ~FileBackgroundIO() {}
+
+  disk_cache::FileIOCallback* callback_;
+
+  disk_cache::File* file_;
+  const void* buf_;
+  size_t buf_len_;
+  size_t offset_;
+
+  DISALLOW_COPY_AND_ASSIGN(FileBackgroundIO);
+};
+
+
+// The specialized controller that keeps track of current operations.
+class FileInFlightIO : public disk_cache::InFlightIO {
+ public:
+  FileInFlightIO() {}
+  virtual ~FileInFlightIO() {}
+
+  // These methods start an asynchronous operation. The arguments have the same
+  // semantics of the File asynchronous operations, with the exception that the
+  // operation never finishes synchronously.
+  void PostRead(disk_cache::File* file, void* buf, size_t buf_len,
+                size_t offset, disk_cache::FileIOCallback* callback);
+  void PostWrite(disk_cache::File* file, const void* buf, size_t buf_len,
+                 size_t offset, disk_cache::FileIOCallback* callback);
+
+ protected:
+  // Invokes the users' completion callback at the end of the IO operation.
+  // |cancel| is true if the actual task posted to the thread is still
+  // queued (because we are inside WaitForPendingIO), and false if said task is
+  // the one performing the call.
+  virtual void OnOperationComplete(disk_cache::BackgroundIO* operation,
+                                   bool cancel) OVERRIDE;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FileInFlightIO);
+};
+
+// ---------------------------------------------------------------------------
+
+// Runs on a worker thread.
+void FileBackgroundIO::Read() {
+  if (file_->Read(const_cast<void*>(buf_), buf_len_, offset_)) {
+    result_ = static_cast<int>(buf_len_);
+  } else {
+    result_ = net::ERR_CACHE_READ_FAILURE;
+  }
+  NotifyController();
+}
+
+// Runs on a worker thread.
+void FileBackgroundIO::Write() {
+  bool rv = file_->Write(buf_, buf_len_, offset_);
+
+  result_ = rv ? static_cast<int>(buf_len_) : net::ERR_CACHE_WRITE_FAILURE;
+  NotifyController();
+}
+
+// ---------------------------------------------------------------------------
+
+void FileInFlightIO::PostRead(disk_cache::File *file, void* buf, size_t buf_len,
+                          size_t offset, disk_cache::FileIOCallback *callback) {
+  scoped_refptr<FileBackgroundIO> operation(
+      new FileBackgroundIO(file, buf, buf_len, offset, callback, this));
+  file->AddRef();  // Balanced on OnOperationComplete()
+
+  base::WorkerPool::PostTask(FROM_HERE,
+      base::Bind(&FileBackgroundIO::Read, operation.get()), true);
+  OnOperationPosted(operation.get());
+}
+
+void FileInFlightIO::PostWrite(disk_cache::File* file, const void* buf,
+                           size_t buf_len, size_t offset,
+                           disk_cache::FileIOCallback* callback) {
+  scoped_refptr<FileBackgroundIO> operation(
+      new FileBackgroundIO(file, buf, buf_len, offset, callback, this));
+  file->AddRef();  // Balanced on OnOperationComplete()
+
+  base::WorkerPool::PostTask(FROM_HERE,
+      base::Bind(&FileBackgroundIO::Write, operation.get()), true);
+  OnOperationPosted(operation.get());
+}
+
+// Runs on the IO thread.
+void FileInFlightIO::OnOperationComplete(disk_cache::BackgroundIO* operation,
+                                         bool cancel) {
+  FileBackgroundIO* op = static_cast<FileBackgroundIO*>(operation);
+
+  disk_cache::FileIOCallback* callback = op->callback();
+  int bytes = operation->result();
+
+  // Release the references acquired in PostRead / PostWrite.
+  op->file()->Release();
+  callback->OnFileIOComplete(bytes);
+}
+
+// A static object tha will broker all async operations.
+FileInFlightIO* s_file_operations = NULL;
+
+// Returns the current FileInFlightIO.
+FileInFlightIO* GetFileInFlightIO() {
+  if (!s_file_operations) {
+    s_file_operations = new FileInFlightIO;
+  }
+  return s_file_operations;
+}
+
+// Deletes the current FileInFlightIO.
+void DeleteFileInFlightIO() {
+  DCHECK(s_file_operations);
+  delete s_file_operations;
+  s_file_operations = NULL;
+}
+
+}  // namespace
+
+namespace disk_cache {
+
+File::File(base::PlatformFile file)
+    : init_(true),
+      mixed_(true),
+      platform_file_(file),
+      sync_platform_file_(base::kInvalidPlatformFileValue) {
+}
+
+bool File::Init(const base::FilePath& name) {
+  if (init_)
+    return false;
+
+  int flags = base::PLATFORM_FILE_OPEN |
+              base::PLATFORM_FILE_READ |
+              base::PLATFORM_FILE_WRITE;
+  platform_file_ = base::CreatePlatformFile(name, flags, NULL, NULL);
+  if (platform_file_ < 0) {
+    platform_file_ = 0;
+    return false;
+  }
+
+  init_ = true;
+  return true;
+}
+
+base::PlatformFile File::platform_file() const {
+  return platform_file_;
+}
+
+bool File::IsValid() const {
+  if (!init_)
+    return false;
+  return (base::kInvalidPlatformFileValue != platform_file_);
+}
+
+bool File::Read(void* buffer, size_t buffer_len, size_t offset) {
+  DCHECK(init_);
+  if (buffer_len > static_cast<size_t>(kint32max) ||
+      offset > static_cast<size_t>(kint32max)) {
+    return false;
+  }
+
+  int ret = base::ReadPlatformFile(platform_file_, offset,
+                                   static_cast<char*>(buffer), buffer_len);
+  return (static_cast<size_t>(ret) == buffer_len);
+}
+
+bool File::Write(const void* buffer, size_t buffer_len, size_t offset) {
+  DCHECK(init_);
+  if (buffer_len > static_cast<size_t>(kint32max) ||
+      offset > static_cast<size_t>(kint32max)) {
+    return false;
+  }
+
+  int ret = base::WritePlatformFile(platform_file_, offset,
+                                    static_cast<const char*>(buffer),
+                                    buffer_len);
+  return (static_cast<size_t>(ret) == buffer_len);
+}
+
+// We have to increase the ref counter of the file before performing the IO to
+// prevent the completion to happen with an invalid handle (if the file is
+// closed while the IO is in flight).
+bool File::Read(void* buffer, size_t buffer_len, size_t offset,
+                FileIOCallback* callback, bool* completed) {
+  DCHECK(init_);
+  if (!callback) {
+    if (completed)
+      *completed = true;
+    return Read(buffer, buffer_len, offset);
+  }
+
+  if (buffer_len > ULONG_MAX || offset > ULONG_MAX)
+    return false;
+
+  GetFileInFlightIO()->PostRead(this, buffer, buffer_len, offset, callback);
+
+  *completed = false;
+  return true;
+}
+
+bool File::Write(const void* buffer, size_t buffer_len, size_t offset,
+                 FileIOCallback* callback, bool* completed) {
+  DCHECK(init_);
+  if (!callback) {
+    if (completed)
+      *completed = true;
+    return Write(buffer, buffer_len, offset);
+  }
+
+  return AsyncWrite(buffer, buffer_len, offset, callback, completed);
+}
+
+bool File::SetLength(size_t length) {
+  DCHECK(init_);
+  if (length > kuint32max)
+    return false;
+
+  return base::TruncatePlatformFile(platform_file_, length);
+}
+
+size_t File::GetLength() {
+  DCHECK(init_);
+  int64 len = base::SeekPlatformFile(platform_file_,
+                                     base::PLATFORM_FILE_FROM_END, 0);
+
+  if (len > static_cast<int64>(kuint32max))
+    return kuint32max;
+
+  return static_cast<size_t>(len);
+}
+
+// Static.
+void File::WaitForPendingIO(int* num_pending_io) {
+  // We may be running unit tests so we should allow be able to reset the
+  // message loop.
+  GetFileInFlightIO()->WaitForPendingIO();
+  DeleteFileInFlightIO();
+}
+
+// Static.
+void File::DropPendingIO() {
+  GetFileInFlightIO()->DropPendingIO();
+  DeleteFileInFlightIO();
+}
+
+File::~File() {
+  if (IsValid())
+    base::ClosePlatformFile(platform_file_);
+}
+
+bool File::AsyncWrite(const void* buffer, size_t buffer_len, size_t offset,
+                      FileIOCallback* callback, bool* completed) {
+  DCHECK(init_);
+  if (buffer_len > ULONG_MAX || offset > ULONG_MAX)
+    return false;
+
+  GetFileInFlightIO()->PostWrite(this, buffer, buffer_len, offset, callback);
+
+  if (completed)
+    *completed = false;
+  return true;
+}
+
+}  // namespace disk_cache
diff --git a/net/disk_cache/file_posix.cc b/net/disk_cache/file_posix.cc
index a4d1964..e1ff6fc 100644
--- a/net/disk_cache/file_posix.cc
+++ b/net/disk_cache/file_posix.cc
@@ -167,6 +167,11 @@ void File::WaitForPendingIO(int* num_pending_io) {
   base::RunLoop().RunUntilIdle();
 }
 
+// Static.
+void File::DropPendingIO() {
+}
+
+
 File::~File() {
   if (IsValid())
     base::ClosePlatformFile(platform_file_);
diff --git a/net/disk_cache/file_win.cc b/net/disk_cache/file_win.cc
index dbb34f3..1492c42 100644
--- a/net/disk_cache/file_win.cc
+++ b/net/disk_cache/file_win.cc
@@ -267,4 +267,8 @@ void File::WaitForPendingIO(int* num_pending_io) {
   }
 }
 
+// Static.
+void File::DropPendingIO() {
+}
+
 }  // namespace disk_cache
diff --git a/net/net.gyp b/net/net.gyp
index 29aad0f..8296763 100644
--- a/net/net.gyp
+++ b/net/net.gyp
@@ -376,6 +376,7 @@
         'disk_cache/file.cc',
         'disk_cache/file.h',
         'disk_cache/file_block.h',
+        'disk_cache/file_ios.cc',
         'disk_cache/file_lock.cc',
         'disk_cache/file_lock.h',
         'disk_cache/file_posix.cc',