| // Copyright 2022 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef COMPONENTS_WEB_PACKAGE_SHARED_FILE_H_ |
| #define COMPONENTS_WEB_PACKAGE_SHARED_FILE_H_ |
| |
| #include <memory> |
| |
| #include "base/callback.h" |
| #include "base/files/file.h" |
| #include "base/memory/ref_counted.h" |
| #include "base/task/sequenced_task_runner.h" |
| #include "mojo/public/cpp/system/data_pipe_producer.h" |
| |
| namespace web_package { |
| |
| // A simple wrapper class to share a single `base::File` instance among multiple |
| // `SharedFile::SharedFileDataSource` instances. |
| class SharedFile final : public base::RefCountedThreadSafe<SharedFile> { |
| public: |
| // The file passed to this method must have been opened for reading. |
| explicit SharedFile(std::unique_ptr<base::File> file); |
| |
| SharedFile(const SharedFile&) = delete; |
| SharedFile& operator=(const SharedFile&) = delete; |
| |
| // Duplicate the underlying `base::File`. This is only needed for APIs that |
| // require a `base::File` and cannot use a `SharedFile`. |
| void DuplicateFile(base::OnceCallback<void(base::File)> callback); |
| |
| // Allow access to the underlying instance of `base::File`. |
| base::File* operator->(); |
| |
| class SharedFileDataSource final : public mojo::DataPipeProducer::DataSource { |
| public: |
| SharedFileDataSource(scoped_refptr<SharedFile> file, |
| uint64_t offset, |
| uint64_t length); |
| |
| SharedFileDataSource(const SharedFileDataSource&) = delete; |
| SharedFileDataSource& operator=(const SharedFileDataSource&) = delete; |
| |
| ~SharedFileDataSource() override; |
| |
| private: |
| // Implements `mojo::DataPipeProducer::DataSource`. The following methods |
| // are called on a blockable sequenced task runner. |
| uint64_t GetLength() const override; |
| ReadResult Read(uint64_t offset, base::span<char> buffer) override; |
| |
| scoped_refptr<SharedFile> file_; |
| MojoResult error_; |
| const uint64_t offset_; |
| const uint64_t length_; |
| }; |
| |
| std::unique_ptr<SharedFileDataSource> CreateDataSource(uint64_t offset, |
| uint64_t length); |
| |
| private: |
| friend class base::RefCountedThreadSafe<SharedFile>; |
| ~SharedFile(); |
| |
| scoped_refptr<base::SequencedTaskRunner> task_runner_; |
| std::unique_ptr<base::File> file_; |
| }; |
| |
| } // namespace web_package |
| |
| #endif // COMPONENTS_WEB_PACKAGE_SHARED_FILE_H_ |