| // 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. |
| |
| #ifndef MOJO_PUBLIC_CPP_SYSTEM_FILE_DATA_PIPE_PRODUCER_H_ |
| #define MOJO_PUBLIC_CPP_SYSTEM_FILE_DATA_PIPE_PRODUCER_H_ |
| |
| #include <memory> |
| |
| #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 "mojo/public/cpp/system/data_pipe.h" |
| #include "mojo/public/cpp/system/system_export.h" |
| |
| namespace mojo { |
| |
| // Helper class which takes ownership of a ScopedDataPipeProducerHandle and |
| // assumes responsibility for feeding it the contents of a given file. This |
| // takes care of waiting for pipe capacity as needed, and can notify callers |
| // asynchronously when the operation is complete. |
| // |
| // Note that the FileDataPipeProducer must be kept alive until notified of |
| // completion to ensure that all of the intended contents are written to the |
| // pipe. Premature destruction may result in partial or total truncation of data |
| // made available to the consumer. |
| class MOJO_CPP_SYSTEM_EXPORT FileDataPipeProducer { |
| public: |
| using CompletionCallback = base::OnceCallback<void(MojoResult result)>; |
| |
| // Interface definition of an optional object that may be supplied to the |
| // FileDataPipeProducer so that the data being read from the consumer can be |
| // observed. |
| class Observer { |
| public: |
| virtual ~Observer() {} |
| |
| // Called once per read attempt. |data| contains the read data (if any). |
| // |num_bytes_read| is the number of read bytes, 0 indicates EOF. Both |
| // parameters may only be used when |read_result| is base::File::FILE_OK. |
| // Can be called on any sequence. |
| virtual void OnBytesRead(const void* data, |
| size_t num_bytes_read, |
| base::File::Error read_result) = 0; |
| |
| // Called when the FileDataPipeProducer has finished reading all data. Will |
| // be called even if there was an error opening the file or reading the |
| // data. Can be called on any sequence. |
| virtual void OnDoneReading() = 0; |
| }; |
| |
| // Constructs a new FileDataPipeProducer which will write data to |producer|. |
| // Caller may supply an optional |observer| if observation of the read file |
| // data is desired. |
| FileDataPipeProducer(ScopedDataPipeProducerHandle producer, |
| std::unique_ptr<Observer> observer); |
| ~FileDataPipeProducer(); |
| |
| // Attempts to eventually write all of |file|'s contents to the pipe. Invokes |
| // |callback| asynchronously when done. Note that |callback| IS allowed to |
| // delete this FileDataPipeProducer. |
| // |
| // If the write is successful |result| will be |MOJO_RESULT_OK|. Otherwise |
| // (e.g. if the producer detects the consumer is closed and the pipe has no |
| // remaining capacity, or if file open/reads fail for any reason) |result| |
| // will be one of the following: |
| // |
| // |MOJO_RESULT_ABORTED| |
| // |MOJO_RESULT_NOT_FOUND| |
| // |MOJO_RESULT_PERMISSION_DENIED| |
| // |MOJO_RESULT_RESOURCE_EXHAUSTED| |
| // |MOJO_RESULT_UNKNOWN| |
| // |
| // Note that if the FileDataPipeProducer is destroyed before |callback| can be |
| // invoked, |callback| is *never* invoked, and the write will be permanently |
| // interrupted (and the producer handle closed) after making potentially only |
| // partial progress. |
| // |
| // Multiple writes may be performed in sequence (each one after the last |
| // completes), but Write() must not be called before the |callback| for the |
| // previous call to Write() (if any) has returned. |
| void WriteFromFile(base::File file, CompletionCallback callback); |
| |
| // Like above, but writes at most |max_bytes| bytes from the file to the pipe. |
| void WriteFromFile(base::File file, |
| size_t max_bytes, |
| CompletionCallback callback); |
| |
| // Same as above but takes a FilePath instead of an opened File. Opens the |
| // file on an appropriate sequence and then proceeds as WriteFromFile() would. |
| void WriteFromPath(const base::FilePath& path, CompletionCallback callback); |
| |
| private: |
| class FileSequenceState; |
| |
| void InitializeNewRequest(CompletionCallback callback); |
| void OnWriteComplete(CompletionCallback callback, |
| ScopedDataPipeProducerHandle producer, |
| MojoResult result); |
| |
| ScopedDataPipeProducerHandle producer_; |
| scoped_refptr<FileSequenceState> file_sequence_state_; |
| std::unique_ptr<Observer> observer_; |
| base::WeakPtrFactory<FileDataPipeProducer> weak_factory_; |
| |
| DISALLOW_COPY_AND_ASSIGN(FileDataPipeProducer); |
| }; |
| |
| } // namespace mojo |
| |
| #endif // MOJO_PUBLIC_CPP_SYSTEM_FILE_DATA_PIPE_PRODUCER_H_ |