Refactor FileIO to the new design

content/renderer/pepper/pepper_file_io_host.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 "content/renderer/pepper/pepper_file_io_host.h"
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "base/file_util_proxy.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/host/dispatch_host_message.h"
+#include "ppapi/host/ppapi_host.h"
+#include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/shared_impl/file_type_conversion.h"
+#include "ppapi/shared_impl/time_conversion.h"
+#include "ppapi/thunk/enter.h"
+#include "webkit/fileapi/file_system_callback_dispatcher.h"
+#include "webkit/plugins/ppapi/file_callbacks.h"
+#include "webkit/plugins/ppapi/host_globals.h"
+#include "webkit/plugins/ppapi/ppapi_plugin_instance.h"
+#include "webkit/plugins/ppapi/ppb_file_ref_impl.h"
+#include "webkit/plugins/ppapi/quota_file_io.h"
+
+namespace content {
+
+using ppapi::FileIOStateManager;
+using ppapi::PPTimeToTime;
+using ppapi::TimeToPPTime;
+using ppapi::host::ReplyMessageContext;
+using ppapi::thunk::EnterResourceNoLock;
+using ppapi::thunk::PPB_FileRef_API;
+using webkit::ppapi::PPB_FileRef_Impl;
+using webkit::ppapi::PluginDelegate;
+
+namespace {
+
+// The maximum size we'll support reading in one chunk. The renderer process
+// must allocate a buffer sized according to the request of the plugin. To
+// keep things from getting out of control, we cap the read size to this value.
+// This should generally be OK since the API specifies that it may perform a
+// partial read.
+static const int32_t kMaxReadSize = 32 * 1024 * 1024;  // 32MB
+
+typedef base::Callback<void (base::PlatformFileError)> PlatformGeneralCallback;
+
+class PlatformGeneralCallbackTranslator
+    : public fileapi::FileSystemCallbackDispatcher {
+ public:
+  PlatformGeneralCallbackTranslator(const PlatformGeneralCallback& callback)
+    : callback_(callback) {}
+
+  virtual ~PlatformGeneralCallbackTranslator() {}
+
+  virtual void DidSucceed() OVERRIDE {
+    callback_.Run(base::PLATFORM_FILE_OK);
+  }
+
+  virtual void DidReadMetadata(const base::PlatformFileInfo& file_info,
+                               const FilePath& platform_path) OVERRIDE {
+    NOTREACHED();
+  }
+
+  virtual void DidReadDirectory(
+      const std::vector<base::FileUtilProxy::Entry>& entries,
+      bool has_more) OVERRIDE {
+    NOTREACHED();
+  }
+
+  virtual void DidOpenFileSystem(const std::string& name,
+                                 const GURL& root) OVERRIDE {
+    NOTREACHED();
+  }
+
+  virtual void DidFail(base::PlatformFileError error_code) OVERRIDE {
+    callback_.Run(error_code);
+  }
+
+  virtual void DidWrite(int64 bytes, bool complete) OVERRIDE {
+    NOTREACHED();
+  }
+
+  virtual void DidOpenFile(base::PlatformFile file) OVERRIDE {
+    NOTREACHED();
+  }
+
+ private:
+  PlatformGeneralCallback callback_;
+};
+
+int32_t ErrorOrByteNumber(int32_t pp_error, int32_t byte_number) {
+  // On the plugin side, some callbacks expect a parameter that means different
+  // things depending on whether is negative or not.  We translate for those
+  // callbacks here.
+  return pp_error == PP_OK ? byte_number : pp_error;
+}
+
+}  // namespace
+
+PepperFileIOHost::PepperFileIOHost(RendererPpapiHost* host,
+                                   PP_Instance instance,
+                                   PP_Resource resource)
+    : ResourceHost(host->GetPpapiHost(), instance, resource),
+      file_(base::kInvalidPlatformFileValue),
+      file_system_type_(PP_FILESYSTEMTYPE_INVALID),
+      weak_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
+  // TODO(victorhsieh): eliminate plugin_delegate_ as it's no longer needed.
+  webkit::ppapi::PluginInstance* plugin_instance =
+      webkit::ppapi::HostGlobals::Get()->GetInstance(instance);
+  plugin_delegate_ = plugin_instance ? plugin_instance->delegate() : NULL;
+}
+
+PepperFileIOHost::~PepperFileIOHost() {
+  OnHostMsgClose(NULL);
+}
+
+int32_t PepperFileIOHost::OnResourceMessageReceived(
+    const IPC::Message& msg,
+    ppapi::host::HostMessageContext* context) {
+  IPC_BEGIN_MESSAGE_MAP(PepperFileIOHost, msg)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_Open,
+                                      OnHostMsgOpen)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FileIO_Query,
+                                        OnHostMsgQuery)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_Touch,
+                                      OnHostMsgTouch)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_Read,
+                                      OnHostMsgRead)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_Write,
+                                      OnHostMsgWrite)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_SetLength,
+                                      OnHostMsgSetLength)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FileIO_Flush,
+                                        OnHostMsgFlush)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FileIO_Close,
+                                        OnHostMsgClose)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_WillWrite,
+                                      OnHostMsgWillWrite)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_WillSetLength,
+                                      OnHostMsgWillSetLength)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FileIO_GetOSFileDescriptor,
+                                        OnHostMsgGetOSFileDescriptor)
+  IPC_END_MESSAGE_MAP()
+  return PP_ERROR_FAILED;
+}
+
+int32_t PepperFileIOHost::OnHostMsgOpen(
+    ppapi::host::HostMessageContext* context,
+    PP_Resource file_ref_resource,
+    int32_t open_flags) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, false);
+  if (rv != PP_OK)
+    return rv;
+
+  int flags = 0;
+  if (!::ppapi::PepperFileOpenFlagsToPlatformFileFlags(open_flags, &flags))
+    return PP_ERROR_BADARGUMENT;
+
+  EnterResourceNoLock<PPB_FileRef_API> enter(file_ref_resource, true);
+  if (enter.failed())
+    return PP_ERROR_BADRESOURCE;
+
+  PPB_FileRef_API* file_ref_api = enter.object();
+  PP_FileSystemType type = file_ref_api->GetFileSystemType();
+  if (type != PP_FILESYSTEMTYPE_LOCALPERSISTENT &&
+      type != PP_FILESYSTEMTYPE_LOCALTEMPORARY &&
+      type != PP_FILESYSTEMTYPE_EXTERNAL)
+    return PP_ERROR_FAILED;
+  file_system_type_ = type;
+
+  if (!plugin_delegate_)
+    return PP_ERROR_FAILED;
+
+  PPB_FileRef_Impl* file_ref = static_cast<PPB_FileRef_Impl*>(file_ref_api);
+  if (file_ref->HasValidFileSystem()) {
+    file_system_url_ = file_ref->GetFileSystemURL();
+    if (!plugin_delegate_->AsyncOpenFileSystemURL(
+            file_system_url_, flags,
+            base::Bind(
+                &PepperFileIOHost::ExecutePlatformOpenFileSystemURLCallback,
+                weak_factory_.GetWeakPtr(),
+                context->MakeReplyMessageContext())))
+      return PP_ERROR_FAILED;
+  } else {
+    if (file_system_type_ != PP_FILESYSTEMTYPE_EXTERNAL)
+      return PP_ERROR_FAILED;
+    if (!plugin_delegate_->AsyncOpenFile(
+            file_ref->GetSystemPath(), flags,
+            base::Bind(&PepperFileIOHost::ExecutePlatformOpenFileCallback,
+                       weak_factory_.GetWeakPtr(),
+                       context->MakeReplyMessageContext())))
+      return PP_ERROR_FAILED;
+  }
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgQuery(
+    ppapi::host::HostMessageContext* context) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (!plugin_delegate_)
+    return PP_ERROR_FAILED;
+
+  if (!base::FileUtilProxy::GetFileInfoFromPlatformFile(
+          plugin_delegate_->GetFileThreadMessageLoopProxy(), file_,
+          base::Bind(&PepperFileIOHost::ExecutePlatformQueryCallback,
+                     weak_factory_.GetWeakPtr(),
+                     context->MakeReplyMessageContext())))
+    return PP_ERROR_FAILED;
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgTouch(
+    ppapi::host::HostMessageContext* context,
+    PP_Time last_access_time,
+    PP_Time last_modified_time) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (!plugin_delegate_)
+    return PP_ERROR_FAILED;
+
+  if (file_system_type_ != PP_FILESYSTEMTYPE_EXTERNAL) {
+    if (!plugin_delegate_->Touch(
+            file_system_url_,
+            PPTimeToTime(last_access_time),
+            PPTimeToTime(last_modified_time),
+            new PlatformGeneralCallbackTranslator(
+                base::Bind(&PepperFileIOHost::ExecutePlatformGeneralCallback,
+                           weak_factory_.GetWeakPtr(),
+                           context->MakeReplyMessageContext()))))
+      return PP_ERROR_FAILED;
+    state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+    return PP_OK_COMPLETIONPENDING;
+  }
+
+  // TODO(nhiroki): fix a failure of FileIO.Touch for an external filesystem on
+  // Mac and Linux due to sandbox restrictions (http://crbug.com/101128).
+  if (!base::FileUtilProxy::Touch(
+          plugin_delegate_->GetFileThreadMessageLoopProxy(),
+          file_, PPTimeToTime(last_access_time),
+          PPTimeToTime(last_modified_time),
+          base::Bind(&PepperFileIOHost::ExecutePlatformGeneralCallback,
+                     weak_factory_.GetWeakPtr(),
+                     context->MakeReplyMessageContext())))
+    return PP_ERROR_FAILED;
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgRead(
+    ppapi::host::HostMessageContext* context,
+    int64_t offset,
+    int32_t max_read_length) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_READ, true);
+  if (rv != PP_OK)
+    return rv;
+
+  // Validate max_read_length before allocating below. This value is coming from
+  // the untrusted plugin.
+  if (max_read_length < 0) {
+    ReplyMessageContext reply_context = context->MakeReplyMessageContext();
+    reply_context.params.set_result(PP_ERROR_FAILED);
+    host()->SendReply(reply_context,
+                      PpapiPluginMsg_FileIO_ReadReply(std::string()));
+    return PP_OK_COMPLETIONPENDING;
+  }
+
+  if (!plugin_delegate_)
+    return PP_ERROR_FAILED;
+
+  if (!base::FileUtilProxy::Read(
+          plugin_delegate_->GetFileThreadMessageLoopProxy(), file_, offset,
+          max_read_length,
+          base::Bind(&PepperFileIOHost::ExecutePlatformReadCallback,
+                     weak_factory_.GetWeakPtr(),
+                     context->MakeReplyMessageContext())))
+    return PP_ERROR_FAILED;
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_READ);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgWrite(
+    ppapi::host::HostMessageContext* context,
+    int64_t offset,
+    const std::string& buffer) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_WRITE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (quota_file_io_.get()) {
+    if (!quota_file_io_->Write(
+            offset, buffer.c_str(), buffer.size(),
+            base::Bind(&PepperFileIOHost::ExecutePlatformWriteCallback,
+                       weak_factory_.GetWeakPtr(),
+                       context->MakeReplyMessageContext())))
+      return PP_ERROR_FAILED;
+  } else {
+    if (!plugin_delegate_)
+      return PP_ERROR_FAILED;
+
+    if (!base::FileUtilProxy::Write(
+            plugin_delegate_->GetFileThreadMessageLoopProxy(), file_, offset,
+            buffer.c_str(), buffer.size(),
+            base::Bind(&PepperFileIOHost::ExecutePlatformWriteCallback,
+                       weak_factory_.GetWeakPtr(),
+                       context->MakeReplyMessageContext())))
+      return PP_ERROR_FAILED;
+  }
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_WRITE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgSetLength(
+    ppapi::host::HostMessageContext* context,
+    int64_t length) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (!plugin_delegate_)
+    return PP_ERROR_FAILED;
+
+  if (file_system_type_ != PP_FILESYSTEMTYPE_EXTERNAL) {
+    if (!plugin_delegate_->SetLength(
+            file_system_url_, length,
+            new PlatformGeneralCallbackTranslator(
+                base::Bind(&PepperFileIOHost::ExecutePlatformGeneralCallback,
+                           weak_factory_.GetWeakPtr(),
+                           context->MakeReplyMessageContext()))))
+      return PP_ERROR_FAILED;
+  } else {
+    // TODO(nhiroki): fix a failure of FileIO.SetLength for an external
+    // filesystem on Mac due to sandbox restrictions (http://crbug.com/156077).
+    if (!base::FileUtilProxy::Truncate(
+            plugin_delegate_->GetFileThreadMessageLoopProxy(), file_, length,
+            base::Bind(&PepperFileIOHost::ExecutePlatformGeneralCallback,
+                       weak_factory_.GetWeakPtr(),
+                       context->MakeReplyMessageContext())))
+      return PP_ERROR_FAILED;
+  }
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgFlush(
+    ppapi::host::HostMessageContext* context) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (!plugin_delegate_)
+    return PP_ERROR_FAILED;
+
+  if (!base::FileUtilProxy::Flush(
+          plugin_delegate_->GetFileThreadMessageLoopProxy(), file_,
+          base::Bind(&PepperFileIOHost::ExecutePlatformGeneralCallback,
+                     weak_factory_.GetWeakPtr(),
+                     context->MakeReplyMessageContext())))
+    return PP_ERROR_FAILED;
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgClose(
+    ppapi::host::HostMessageContext* context) {
+  if (file_ != base::kInvalidPlatformFileValue && plugin_delegate_) {
+    base::FileUtilProxy::Close(
+        plugin_delegate_->GetFileThreadMessageLoopProxy(),
+        file_,
+        base::ResetAndReturn(&notify_close_file_callback_));
+    file_ = base::kInvalidPlatformFileValue;
+    quota_file_io_.reset();
+  }
+  return PP_OK;
+}
+
+int32_t PepperFileIOHost::OnHostMsgWillWrite(
+    ppapi::host::HostMessageContext* context,
+    int64_t offset,
+    int32_t bytes_to_write) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (!quota_file_io_.get())
+    return PP_OK;
+
+  if (!quota_file_io_->WillWrite(
+          offset, bytes_to_write,
+          base::Bind(&PepperFileIOHost::ExecutePlatformWillWriteCallback,
+                     weak_factory_.GetWeakPtr(),
+                     context->MakeReplyMessageContext())))
+    return PP_ERROR_FAILED;
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgWillSetLength(
+    ppapi::host::HostMessageContext* context,
+    int64_t length) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (!quota_file_io_.get())
+    return PP_OK;
+
+  if (!quota_file_io_->WillSetLength(
+          length,
+          base::Bind(&PepperFileIOHost::ExecutePlatformGeneralCallback,
+                     weak_factory_.GetWeakPtr(),
+                     context->MakeReplyMessageContext())))
+    return PP_ERROR_FAILED;
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgGetOSFileDescriptor(
+    ppapi::host::HostMessageContext* context) {
+  //if (!host()->IsRunningInProcess())
+  //  return PP_ERROR_FAILED;
+  int32_t fd =
+#if defined(OS_POSIX)
+    file_;
+#elif defined(OS_WIN)
+    reinterpret_cast<uintptr_t>(file_);
+#else
+    -1;  // Platform not supported.
+#endif
+  // TODO(victorhsieh): Pass the file handle in the reply params once this works
+  // in-process.
+  host()->SendReply(context->MakeReplyMessageContext(),
+      PpapiPluginMsg_FileIO_GetOSFileDescriptorReply(fd));
+  return PP_OK_COMPLETIONPENDING;
+}
+
+void PepperFileIOHost::ExecutePlatformGeneralCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code) {
+  reply_context.params.set_result(
+      ::ppapi::PlatformFileErrorToPepperError(error_code));
+  host()->SendReply(reply_context, PpapiPluginMsg_FileIO_GeneralReply());
+  state_manager_.OperationFinished();
+}
+
+void PepperFileIOHost::ExecutePlatformOpenFileCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code,
+    base::PassPlatformFile file) {
+  int32_t pp_error = ::ppapi::PlatformFileErrorToPepperError(error_code);
+  if (pp_error == PP_OK)
+    state_manager_.SetOpenSucceed();
+
+  DCHECK(file_ == base::kInvalidPlatformFileValue);
+  file_ = file.ReleaseValue();
+
+  DCHECK(!quota_file_io_.get());
+  if (file_ != base::kInvalidPlatformFileValue &&
+      (file_system_type_ == PP_FILESYSTEMTYPE_LOCALTEMPORARY ||
+       file_system_type_ == PP_FILESYSTEMTYPE_LOCALPERSISTENT)) {
+    quota_file_io_.reset(new webkit::ppapi::QuotaFileIO(
+        pp_instance(), file_, file_system_url_, file_system_type_));
+  }
+
+  reply_context.params.set_result(pp_error);
+  host()->SendReply(reply_context, PpapiPluginMsg_FileIO_OpenReply());
+  state_manager_.OperationFinished();
+}
+
+void PepperFileIOHost::ExecutePlatformOpenFileSystemURLCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code,
+    base::PassPlatformFile file,
+    const PluginDelegate::NotifyCloseFileCallback& callback) {
+  if (error_code == base::PLATFORM_FILE_OK)
+    notify_close_file_callback_ = callback;
+  ExecutePlatformOpenFileCallback(reply_context, error_code, file);
+}
+
+void PepperFileIOHost::ExecutePlatformQueryCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code,
+    const base::PlatformFileInfo& file_info) {
+  PP_FileInfo pp_info;
+  pp_info.size = file_info.size;
+  pp_info.creation_time = TimeToPPTime(file_info.creation_time);
+  pp_info.last_access_time = TimeToPPTime(file_info.last_accessed);
+  pp_info.last_modified_time = TimeToPPTime(file_info.last_modified);
+  pp_info.system_type = file_system_type_;
+  if (file_info.is_directory)
+    pp_info.type = PP_FILETYPE_DIRECTORY;
+  else
+    pp_info.type = PP_FILETYPE_REGULAR;
+
+  int32_t pp_error = ::ppapi::PlatformFileErrorToPepperError(error_code);
+  reply_context.params.set_result(pp_error);
+  host()->SendReply(reply_context,
+                    PpapiPluginMsg_FileIO_QueryReply(pp_info));
+  state_manager_.OperationFinished();
+}
+
+void PepperFileIOHost::ExecutePlatformReadCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code,
+    const char* data, int bytes_read) {
+  int32_t pp_error = ::ppapi::PlatformFileErrorToPepperError(error_code);
+
+  // Only send the amount of data in the string that was actually read.
+  std::string buffer;
+  if (pp_error == PP_OK)
+    buffer.append(data, bytes_read);
+  reply_context.params.set_result(ErrorOrByteNumber(pp_error, bytes_read));
+  host()->SendReply(reply_context, PpapiPluginMsg_FileIO_ReadReply(buffer));
+  state_manager_.OperationFinished();
+}
+
+void PepperFileIOHost::ExecutePlatformWriteCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code,
+    int bytes_written) {
+  int32_t pp_error = ::ppapi::PlatformFileErrorToPepperError(error_code);
+  reply_context.params.set_result(ErrorOrByteNumber(pp_error, bytes_written));
+  host()->SendReply(reply_context, PpapiPluginMsg_FileIO_GeneralReply());
+  state_manager_.OperationFinished();
+}
+
+void PepperFileIOHost::ExecutePlatformWillWriteCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code,
+    int bytes_written) {
+  // On the plugin side, the callback expects a parameter with different meaning
+  // depends on whether is negative or not.  It is the result here.  We
+  // translate for the callback.
+  int32_t pp_error = ::ppapi::PlatformFileErrorToPepperError(error_code);
+  reply_context.params.set_result(ErrorOrByteNumber(pp_error, bytes_written));
+  host()->SendReply(reply_context, PpapiPluginMsg_FileIO_GeneralReply());
+  state_manager_.OperationFinished();
+}
+
+}  // namespace content