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// Copyright 2017 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 <stdint.h>
#include <string>
#include <vector>
#include "base/callback_forward.h"
#include "base/files/file.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "media/cdm/api/content_decryption_module.h"
#include "media/mojo/interfaces/cdm_storage.mojom.h"
#include "media/mojo/services/media_mojo_export.h"
namespace media {
// TODO( This class should do the Read/Write operations on a
// separate thread so as to not impact decoding happening on the same thread.
// The new thread may need to block shutdown so that the file is not corrupted.
// Implements a cdm::FileIO that communicates with mojom::CdmStorage.
class MEDIA_MOJO_EXPORT MojoCdmFileIO : public cdm::FileIO {
class Delegate {
// Notifies the delegate to close |cdm_file_io|.
virtual void CloseCdmFileIO(MojoCdmFileIO* cdm_file_io) = 0;
// Reports the size of file read by MojoCdmFileIO.
virtual void ReportFileReadSize(int file_size_bytes) = 0;
// The constructor and destructor of cdm::FileIO are protected so that the CDM
// cannot delete the object directly. Here we declare the constructor and
// destructor as public so that we can use std::unique_ptr<> for better memory
// management.
MojoCdmFileIO(Delegate* delegate,
cdm::FileIOClient* client,
mojom::CdmStorage* cdm_storage);
~MojoCdmFileIO() override;
// cdm::FileIO implementation.
void Open(const char* file_name, uint32_t file_name_size) final;
void Read() final;
void Write(const uint8_t* data, uint32_t data_size) final;
void Close() final;
// Allowed state transitions:
// kUnopened -> kOpening -> kOpened
// kUnopened -> kOpening -> kUnopened (if file in use)
// kUnopened -> kOpening -> kError (if file not available)
// kOpened -> kReading -> kOpened
// kOpened -> kWriting -> kOpened
// Once state = kError, only Close() can be called.
enum class State { kUnopened, kOpening, kOpened, kReading, kWriting, kError };
// Error that needs to be reported back to the client.
enum class ErrorType {
// Called when the file is opened (or not).
void OnFileOpened(mojom::CdmStorage::Status status,
base::File file,
mojom::CdmFileAssociatedPtrInfo cdm_file);
// Reading the file is done asynchronously.
void DoRead(int64_t num_bytes);
// Called when a temporary file has been opened for writing.
void DoWrite(const std::vector<uint8_t>& data, base::File temporary_file);
// Called after the write has been committed and replaces the original file.
void OnWriteCommitted(base::File reopened_file);
// Called when an error occurs. Calls client_->OnXxxxComplete with kError
// or kInUse asynchronously. In some cases we could actually call them
// synchronously, but since these errors shouldn't happen in normal cases,
// we are not optimizing such cases.
void OnError(ErrorType error);
// Callback to notify client of error asynchronously.
void NotifyClientOfError(ErrorType error);
Delegate* delegate_ = nullptr;
// Results of cdm::FileIO operations are sent asynchronously via |client_|.
cdm::FileIOClient* client_ = nullptr;
mojom::CdmStorage* cdm_storage_ = nullptr;
// Keep track of the file being used. As this class can only be used for
// accessing a single file, once |file_name_| is set it shouldn't be changed.
// |file_name_| is only saved for logging purposes.
std::string file_name_;
// Current file open for reading.
base::File file_for_reading_;
// |cdm_file_| is used to write to the file and is released when the file is
// closed so that CdmStorage can tell that the file is no longer being used.
mojom::CdmFileAssociatedPtr cdm_file_;
// Keep track of operations in progress.
State state_ = State::kUnopened;
// NOTE: Weak pointers must be invalidated before all other member variables.
base::WeakPtrFactory<MojoCdmFileIO> weak_factory_;
} // namespace media