| // 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_STRING_DATA_PIPE_PRODUCER_H_ |
| #define MOJO_PUBLIC_CPP_SYSTEM_STRING_DATA_PIPE_PRODUCER_H_ |
| |
| #include <string> |
| |
| #include "base/callback_forward.h" |
| #include "base/macros.h" |
| #include "base/memory/weak_ptr.h" |
| #include "base/strings/string_piece.h" |
| #include "mojo/public/cpp/system/data_pipe.h" |
| #include "mojo/public/cpp/system/simple_watcher.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 string. This |
| // takes care of waiting for pipe capacity as needed, and can notify callers |
| // asynchronously when the operation is complete. |
| // |
| // Note that the StringDataPipeProducer must be kept alive until notified of |
| // completion to ensure that all of the string's data is 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 StringDataPipeProducer { |
| public: |
| using CompletionCallback = base::OnceCallback<void(MojoResult result)>; |
| |
| // Constructs a new StringDataPipeProducer which will write data to |
| // |producer|. |
| explicit StringDataPipeProducer(ScopedDataPipeProducerHandle producer); |
| ~StringDataPipeProducer(); |
| |
| // Attempts to eventually write all of |data|. Invokes |callback| |
| // asynchronously when done. Note that |callback| IS allowed to delete this |
| // StringDataPipeProducer. |
| // |
| // 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) |result| will be |MOJO_RESULT_ABORTED|. |
| // |
| // Note that if the StringDataPipeProducer 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 Write(const base::StringPiece& data, CompletionCallback callback); |
| |
| private: |
| void InvokeCallback(MojoResult result); |
| void OnProducerHandleReady(MojoResult ready_result, |
| const HandleSignalsState& state); |
| |
| ScopedDataPipeProducerHandle producer_; |
| std::string data_; |
| base::StringPiece data_view_; |
| CompletionCallback callback_; |
| SimpleWatcher watcher_; |
| base::WeakPtrFactory<StringDataPipeProducer> weak_factory_; |
| |
| DISALLOW_COPY_AND_ASSIGN(StringDataPipeProducer); |
| }; |
| |
| } // namespace mojo |
| |
| #endif // MOJO_PUBLIC_CPP_SYSTEM_STRING_DATA_PIPE_PRODUCER_H_ |