Implement SandboxFileWriter and rewrite FileWriterDelegate to use it

webkit/fileapi/sandbox_file_writer.cc

+// Copyright (c) 2012 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 "webkit/fileapi/sandbox_file_writer.h"
+
+#include "base/file_util_proxy.h"
+#include "base/platform_file.h"
+#include "base/sequenced_task_runner.h"
+#include "net/base/io_buffer.h"
+#include "net/base/net_errors.h"
+#include "webkit/blob/local_file_reader.h"
+#include "webkit/fileapi/file_system_context.h"
+#include "webkit/fileapi/file_system_operation_interface.h"
+#include "webkit/fileapi/file_system_quota_util.h"
+#include "webkit/fileapi/file_system_util.h"
+#include "webkit/fileapi/local_file_writer.h"
+#include "webkit/quota/quota_manager.h"
+
+namespace fileapi {
+
+namespace {
+
+int PlatformFileErrorToNetError(base::PlatformFileError error) {
+  // TODO(kinuko): Move this static method to more convenient place.
+  return webkit_blob::LocalFileReader::PlatformFileErrorToNetError(error);
+}
+
+// Adjust the |quota| value with given |file_offset| and |file_size| and
+// return the new quota value.

[ericu, 2012/05/16 00:23:17]

The comments and name here aren't clear.  They should explain what and why the
adjustment is, not just that there is one.

[kinuko, 2012/05/16 04:10:12]

Updated the comment.

[ericu, 2012/05/17 00:04:13]

Very nice--thanks.

+int64 AdjustQuotaWithFileRange(int64 quota,
+                               int64 file_offset,
+                               int64 file_size) {
+  DCHECK_LE(file_offset, file_size);
+  if (quota < 0)
+    quota = 0;
+  int64 overlap = file_size - file_offset;
+  if (kint64max - overlap > quota)
+    quota += overlap;
+  return quota;
+}
+
+}  // namespace
+
+SandboxFileWriter::SandboxFileWriter(
+    FileSystemContext* file_system_context,
+    const GURL& url,
+    int64 initial_offset)
+    : file_system_context_(file_system_context),
+      url_(url),
+      initial_offset_(initial_offset),
+      file_size_(0),
+      total_bytes_written_(0),
+      allowed_bytes_to_write_(0),
+      has_pending_operation_(false),
+      default_quota_(kint64max),
+      weak_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
+  const bool result = CrackFileSystemURL(
+      url_, &origin_, &file_system_type_, &virtual_path_);
+  DCHECK(result);
+}
+
+SandboxFileWriter::~SandboxFileWriter() {
+  if (quota_util())
+    quota_util()->proxy()->EndUpdateOrigin(origin_, file_system_type_);
+}
+
+int SandboxFileWriter::Write(
+    net::IOBuffer* buf, int buf_len,
+    const net::CompletionCallback& callback) {
+  has_pending_operation_ = true;
+  if (local_file_writer_.get())
+    return WriteInternal(buf, buf_len, callback);
+
+  FileSystemOperationInterface* operation =
+      file_system_context_->CreateFileSystemOperation(url_);
+  DCHECK(operation);
+  net::CompletionCallback write_task =
+      base::Bind(&SandboxFileWriter::DidInitializeForWrite,
+                 weak_factory_.GetWeakPtr(),
+                 make_scoped_refptr(buf), buf_len, callback);
+  operation->GetMetadata(
+      url_, base::Bind(&SandboxFileWriter::DidGetFileInfo,
+                       weak_factory_.GetWeakPtr(), write_task));
+  return net::ERR_IO_PENDING;
+}
+
+int SandboxFileWriter::Cancel(const net::CompletionCallback& callback) {
+  if (!has_pending_operation_)
+    return net::ERR_UNEXPECTED;
+
+  DCHECK(local_file_writer_.get());

[ericu, 2012/05/16 00:23:17]

If you call Write, then quickly call Cancel before initialization completes,
won't local_file_writer_ be NULL?

[kinuko, 2012/05/16 04:10:12]

You're right, I just found this problem while running a layout test.  Removed
this line.

+  DCHECK(!callback.is_null());
+  cancel_callback_ = callback;
+  return net::ERR_IO_PENDING;
+}
+
+int SandboxFileWriter::WriteInternal(
+    net::IOBuffer* buf, int buf_len,
+    const net::CompletionCallback& callback) {
+  // allowed_bytes_to_write could be negative if the file size is
+  // greater than the current (possibly new) quota.
+  DCHECK(total_bytes_written_ <= allowed_bytes_to_write_ ||
+         allowed_bytes_to_write_ < 0);
+  if (total_bytes_written_ >= allowed_bytes_to_write_) {
+    has_pending_operation_ = false;
+    return net::ERR_FILE_NO_SPACE;
+  }
+
+  if (buf_len > allowed_bytes_to_write_ - total_bytes_written_)
+    buf_len = allowed_bytes_to_write_ - total_bytes_written_;
+
+  DCHECK(local_file_writer_.get());
+  const int result = local_file_writer_->Write(
+      buf, buf_len,
+      base::Bind(&SandboxFileWriter::DidWrite, weak_factory_.GetWeakPtr(),
+                 callback));
+  if (result != net::ERR_IO_PENDING)
+    has_pending_operation_ = false;
+  return result;
+}
+
+void SandboxFileWriter::DidGetFileInfo(
+    const net::CompletionCallback& callback,
+    base::PlatformFileError file_error,
+    const base::PlatformFileInfo& file_info,
+    const FilePath& platform_path) {
+  if (CancelIfRequested())
+    return;
+  if (file_error != base::PLATFORM_FILE_OK) {
+    callback.Run(PlatformFileErrorToNetError(file_error));
+    return;
+  }
+  if (file_info.is_directory) {
+    // We should not be writing to a directory.
+    callback.Run(net::ERR_ACCESS_DENIED);
+    return;
+  }
+  file_size_ = file_info.size;
+  if (initial_offset_ > file_size_) {
+    LOG(ERROR) << initial_offset_ << ", " << file_size_;
+    // This shouldn't happen as long as we check offset in the renderer.
+    NOTREACHED();
+    initial_offset_ = file_size_;
+  }
+  DCHECK(!local_file_writer_.get());
+  local_file_writer_.reset(new LocalFileWriter(platform_path, initial_offset_));
+
+  quota::QuotaManagerProxy* quota_manager_proxy =
+      file_system_context_->quota_manager_proxy();
+  if (!quota_manager_proxy || !quota_util()) {
+    // If we don't have the quota manager or the requested filesystem type
+    // does not support quota, we should be able to let it go.
+    allowed_bytes_to_write_ = default_quota_;
+    callback.Run(net::OK);
+    return;
+  }
+
+  quota_util()->proxy()->StartUpdateOrigin(origin_, file_system_type_);
+  DCHECK(quota_manager_proxy->quota_manager());
+  quota_manager_proxy->quota_manager()->GetUsageAndQuota(
+      origin_,
+      FileSystemTypeToQuotaStorageType(file_system_type_),
+      base::Bind(&SandboxFileWriter::DidGetUsageAndQuota,
+                 weak_factory_.GetWeakPtr(), callback));
+}
+
+void SandboxFileWriter::DidGetUsageAndQuota(
+    const net::CompletionCallback& callback,
+    quota::QuotaStatusCode status,
+    int64 usage, int64 quota) {
+  if (status != quota::kQuotaStatusOk) {
+    LOG(WARNING) << "Got unexpected quota error : " << status;
+    callback.Run(net::ERR_FAILED);
+    return;
+  }
+
+  allowed_bytes_to_write_ = quota - usage;
+  callback.Run(net::OK);
+}
+
+void SandboxFileWriter::DidInitializeForWrite(
+    net::IOBuffer* buf, int buf_len,
+    const net::CompletionCallback& callback,
+    int init_status) {
+  if (init_status != net::OK) {
+    has_pending_operation_ = false;
+    callback.Run(init_status);
+    return;
+  }
+  allowed_bytes_to_write_ = AdjustQuotaWithFileRange(
+      allowed_bytes_to_write_, initial_offset_, file_size_);
+  const int result = WriteInternal(buf, buf_len, callback);
+  if (result != net::ERR_IO_PENDING)
+    callback.Run(result);
+}
+
+void SandboxFileWriter::DidWrite(
+    const net::CompletionCallback& callback,
+    int write_response) {
+  DCHECK(has_pending_operation_);
+  has_pending_operation_ = false;
+
+  if (write_response <= 0) {
+    if (CancelIfRequested())
+      return;
+    callback.Run(write_response);
+    return;
+  }
+
+  if (quota_util() &&
+      total_bytes_written_ + write_response + initial_offset_ > file_size_) {
+    int overlapped = file_size_ - total_bytes_written_ - initial_offset_;
+    if (overlapped < 0)
+      overlapped = 0;
+    quota_util()->proxy()->UpdateOriginUsage(
+        file_system_context_->quota_manager_proxy(),
+        origin_, file_system_type_, write_response - overlapped);
+  }
+  total_bytes_written_ += write_response;
+
+  if (CancelIfRequested())
+    return;
+  callback.Run(write_response);
+}
+
+bool SandboxFileWriter::CancelIfRequested() {
+  if (cancel_callback_.is_null())
+    return false;
+
+  net::CompletionCallback pending_cancel = cancel_callback_;
+  has_pending_operation_ = false;
+  cancel_callback_.Reset();
+  pending_cancel.Run(net::OK);
+  return true;
+}
+
+FileSystemQuotaUtil* SandboxFileWriter::quota_util() const {
+  DCHECK(file_system_context_.get());
+  return file_system_context_->GetQuotaUtil(file_system_type_);
+}
+
+}  // namespace fileapi