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28 #ifndef TALK_BASE_STREAM_H_
29 #define TALK_BASE_STREAM_H_
31 #include "talk/base/basictypes.h"
32 #include "talk/base/buffer.h"
33 #include "talk/base/criticalsection.h"
34 #include "talk/base/logging.h"
35 #include "talk/base/messagehandler.h"
36 #include "talk/base/messagequeue.h"
37 #include "talk/base/scoped_ptr.h"
38 #include "talk/base/sigslot.h"
42 ///////////////////////////////////////////////////////////////////////////////
43 // StreamInterface is a generic asynchronous stream interface, supporting read,
44 // write, and close operations, and asynchronous signalling of state changes.
45 // The interface is designed with file, memory, and socket implementations in
46 // mind. Some implementations offer extended operations, such as seeking.
47 ///////////////////////////////////////////////////////////////////////////////
49 // The following enumerations are declared outside of the StreamInterface
50 // class for brevity in use.
52 // The SS_OPENING state indicates that the stream will signal open or closed
54 enum StreamState { SS_CLOSED, SS_OPENING, SS_OPEN };
56 // Stream read/write methods return this value to indicate various success
57 // and failure conditions described below.
58 enum StreamResult { SR_ERROR, SR_SUCCESS, SR_BLOCK, SR_EOS };
60 // StreamEvents are used to asynchronously signal state transitionss. The flags
62 // SE_OPEN: The stream has transitioned to the SS_OPEN state
63 // SE_CLOSE: The stream has transitioned to the SS_CLOSED state
64 // SE_READ: Data is available, so Read is likely to not return SR_BLOCK
65 // SE_WRITE: Data can be written, so Write is likely to not return SR_BLOCK
66 enum StreamEvent { SE_OPEN = 1, SE_READ = 2, SE_WRITE = 4, SE_CLOSE = 8 };
70 struct StreamEventData : public MessageData {
72 StreamEventData(int ev, int er) : events(ev), error(er) { }
75 class StreamInterface : public MessageHandler {
78 MSG_POST_EVENT = 0xF1F1, MSG_MAX = MSG_POST_EVENT
81 virtual ~StreamInterface();
83 virtual StreamState GetState() const = 0;
85 // Read attempts to fill buffer of size buffer_len. Write attempts to send
86 // data_len bytes stored in data. The variables read and write are set only
87 // on SR_SUCCESS (see below). Likewise, error is only set on SR_ERROR.
88 // Read and Write return a value indicating:
89 // SR_ERROR: an error occurred, which is returned in a non-null error
90 // argument. Interpretation of the error requires knowledge of the
91 // stream's concrete type, which limits its usefulness.
92 // SR_SUCCESS: some number of bytes were successfully written, which is
93 // returned in a non-null read/write argument.
94 // SR_BLOCK: the stream is in non-blocking mode, and the operation would
95 // block, or the stream is in SS_OPENING state.
96 // SR_EOS: the end-of-stream has been reached, or the stream is in the
98 virtual StreamResult Read(void* buffer, size_t buffer_len,
99 size_t* read, int* error) = 0;
100 virtual StreamResult Write(const void* data, size_t data_len,
101 size_t* written, int* error) = 0;
102 // Attempt to transition to the SS_CLOSED state. SE_CLOSE will not be
103 // signalled as a result of this call.
104 virtual void Close() = 0;
106 // Streams may signal one or more StreamEvents to indicate state changes.
107 // The first argument identifies the stream on which the state change occured.
108 // The second argument is a bit-wise combination of StreamEvents.
109 // If SE_CLOSE is signalled, then the third argument is the associated error
110 // code. Otherwise, the value is undefined.
111 // Note: Not all streams will support asynchronous event signalling. However,
112 // SS_OPENING and SR_BLOCK returned from stream member functions imply that
113 // certain events will be raised in the future.
114 sigslot::signal3<StreamInterface*, int, int> SignalEvent;
116 // Like calling SignalEvent, but posts a message to the specified thread,
117 // which will call SignalEvent. This helps unroll the stack and prevent
119 void PostEvent(Thread* t, int events, int err);
120 // Like the aforementioned method, but posts to the current thread.
121 void PostEvent(int events, int err);
124 // OPTIONAL OPERATIONS
126 // Not all implementations will support the following operations. In general,
127 // a stream will only support an operation if it reasonably efficient to do
128 // so. For example, while a socket could buffer incoming data to support
129 // seeking, it will not do so. Instead, a buffering stream adapter should
132 // Even though several of these operations are related, you should
133 // always use whichever operation is most relevant. For example, you may
134 // be tempted to use GetSize() and GetPosition() to deduce the result of
135 // GetAvailable(). However, a stream which is read-once may support the
136 // latter operation but not the former.
139 // The following four methods are used to avoid copying data multiple times.
141 // GetReadData returns a pointer to a buffer which is owned by the stream.
142 // The buffer contains data_len bytes. NULL is returned if no data is
143 // available, or if the method fails. If the caller processes the data, it
144 // must call ConsumeReadData with the number of processed bytes. GetReadData
145 // does not require a matching call to ConsumeReadData if the data is not
146 // processed. Read and ConsumeReadData invalidate the buffer returned by
148 virtual const void* GetReadData(size_t* data_len) { return NULL; }
149 virtual void ConsumeReadData(size_t used) {}
151 // GetWriteBuffer returns a pointer to a buffer which is owned by the stream.
152 // The buffer has a capacity of buf_len bytes. NULL is returned if there is
153 // no buffer available, or if the method fails. The call may write data to
154 // the buffer, and then call ConsumeWriteBuffer with the number of bytes
155 // written. GetWriteBuffer does not require a matching call to
156 // ConsumeWriteData if no data is written. Write, ForceWrite, and
157 // ConsumeWriteData invalidate the buffer returned by GetWriteBuffer.
158 // TODO: Allow the caller to specify a minimum buffer size. If the specified
159 // amount of buffer is not yet available, return NULL and Signal SE_WRITE
160 // when it is available. If the requested amount is too large, return an
162 virtual void* GetWriteBuffer(size_t* buf_len) { return NULL; }
163 virtual void ConsumeWriteBuffer(size_t used) {}
165 // Write data_len bytes found in data, circumventing any throttling which
166 // would could cause SR_BLOCK to be returned. Returns true if all the data
167 // was written. Otherwise, the method is unsupported, or an unrecoverable
168 // error occurred, and the error value is set. This method should be used
169 // sparingly to write critical data which should not be throttled. A stream
170 // which cannot circumvent its blocking constraints should not implement this
172 // NOTE: This interface is being considered experimentally at the moment. It
173 // would be used by JUDP and BandwidthStream as a way to circumvent certain
174 // soft limits in writing.
175 //virtual bool ForceWrite(const void* data, size_t data_len, int* error) {
176 // if (error) *error = -1;
180 // Seek to a byte offset from the beginning of the stream. Returns false if
181 // the stream does not support seeking, or cannot seek to the specified
183 virtual bool SetPosition(size_t position) { return false; }
185 // Get the byte offset of the current position from the start of the stream.
186 // Returns false if the position is not known.
187 virtual bool GetPosition(size_t* position) const { return false; }
189 // Get the byte length of the entire stream. Returns false if the length
191 virtual bool GetSize(size_t* size) const { return false; }
193 // Return the number of Read()-able bytes remaining before end-of-stream.
194 // Returns false if not known.
195 virtual bool GetAvailable(size_t* size) const { return false; }
197 // Return the number of Write()-able bytes remaining before end-of-stream.
198 // Returns false if not known.
199 virtual bool GetWriteRemaining(size_t* size) const { return false; }
201 // Return true if flush is successful.
202 virtual bool Flush() { return false; }
204 // Communicates the amount of data which will be written to the stream. The
205 // stream may choose to preallocate memory to accomodate this data. The
206 // stream may return false to indicate that there is not enough room (ie,
207 // Write will return SR_EOS/SR_ERROR at some point). Note that calling this
208 // function should not affect the existing state of data in the stream.
209 virtual bool ReserveSize(size_t size) { return true; }
212 // CONVENIENCE METHODS
214 // These methods are implemented in terms of other methods, for convenience.
217 // Seek to the start of the stream.
218 inline bool Rewind() { return SetPosition(0); }
220 // WriteAll is a helper function which repeatedly calls Write until all the
221 // data is written, or something other than SR_SUCCESS is returned. Note that
222 // unlike Write, the argument 'written' is always set, and may be non-zero
223 // on results other than SR_SUCCESS. The remaining arguments have the
224 // same semantics as Write.
225 StreamResult WriteAll(const void* data, size_t data_len,
226 size_t* written, int* error);
228 // Similar to ReadAll. Calls Read until buffer_len bytes have been read, or
229 // until a non-SR_SUCCESS result is returned. 'read' is always set.
230 StreamResult ReadAll(void* buffer, size_t buffer_len,
231 size_t* read, int* error);
233 // ReadLine is a helper function which repeatedly calls Read until it hits
234 // the end-of-line character, or something other than SR_SUCCESS.
235 // TODO: this is too inefficient to keep here. Break this out into a buffered
236 // readline object or adapter
237 StreamResult ReadLine(std::string* line);
242 // MessageHandler Interface
243 virtual void OnMessage(Message* msg);
246 DISALLOW_EVIL_CONSTRUCTORS(StreamInterface);
249 ///////////////////////////////////////////////////////////////////////////////
250 // StreamAdapterInterface is a convenient base-class for adapting a stream.
251 // By default, all operations are pass-through. Override the methods that you
252 // require adaptation. Streams should really be upgraded to reference-counted.
253 // In the meantime, use the owned flag to indicate whether the adapter should
254 // own the adapted stream.
255 ///////////////////////////////////////////////////////////////////////////////
257 class StreamAdapterInterface : public StreamInterface,
258 public sigslot::has_slots<> {
260 explicit StreamAdapterInterface(StreamInterface* stream, bool owned = true);
262 // Core Stream Interface
263 virtual StreamState GetState() const {
264 return stream_->GetState();
266 virtual StreamResult Read(void* buffer, size_t buffer_len,
267 size_t* read, int* error) {
268 return stream_->Read(buffer, buffer_len, read, error);
270 virtual StreamResult Write(const void* data, size_t data_len,
271 size_t* written, int* error) {
272 return stream_->Write(data, data_len, written, error);
274 virtual void Close() {
278 // Optional Stream Interface
279 /* Note: Many stream adapters were implemented prior to this Read/Write
280 interface. Therefore, a simple pass through of data in those cases may
281 be broken. At a later time, we should do a once-over pass of all
282 adapters, and make them compliant with these interfaces, after which this
283 code can be uncommented.
284 virtual const void* GetReadData(size_t* data_len) {
285 return stream_->GetReadData(data_len);
287 virtual void ConsumeReadData(size_t used) {
288 stream_->ConsumeReadData(used);
291 virtual void* GetWriteBuffer(size_t* buf_len) {
292 return stream_->GetWriteBuffer(buf_len);
294 virtual void ConsumeWriteBuffer(size_t used) {
295 stream_->ConsumeWriteBuffer(used);
299 /* Note: This interface is currently undergoing evaluation.
300 virtual bool ForceWrite(const void* data, size_t data_len, int* error) {
301 return stream_->ForceWrite(data, data_len, error);
305 virtual bool SetPosition(size_t position) {
306 return stream_->SetPosition(position);
308 virtual bool GetPosition(size_t* position) const {
309 return stream_->GetPosition(position);
311 virtual bool GetSize(size_t* size) const {
312 return stream_->GetSize(size);
314 virtual bool GetAvailable(size_t* size) const {
315 return stream_->GetAvailable(size);
317 virtual bool GetWriteRemaining(size_t* size) const {
318 return stream_->GetWriteRemaining(size);
320 virtual bool ReserveSize(size_t size) {
321 return stream_->ReserveSize(size);
323 virtual bool Flush() {
324 return stream_->Flush();
327 void Attach(StreamInterface* stream, bool owned = true);
328 StreamInterface* Detach();
331 virtual ~StreamAdapterInterface();
333 // Note that the adapter presents itself as the origin of the stream events,
334 // since users of the adapter may not recognize the adapted object.
335 virtual void OnEvent(StreamInterface* stream, int events, int err) {
336 SignalEvent(this, events, err);
338 StreamInterface* stream() { return stream_; }
341 StreamInterface* stream_;
343 DISALLOW_EVIL_CONSTRUCTORS(StreamAdapterInterface);
346 ///////////////////////////////////////////////////////////////////////////////
347 // StreamTap is a non-modifying, pass-through adapter, which copies all data
348 // in either direction to the tap. Note that errors or blocking on writing to
349 // the tap will prevent further tap writes from occurring.
350 ///////////////////////////////////////////////////////////////////////////////
352 class StreamTap : public StreamAdapterInterface {
354 explicit StreamTap(StreamInterface* stream, StreamInterface* tap);
356 void AttachTap(StreamInterface* tap);
357 StreamInterface* DetachTap();
358 StreamResult GetTapResult(int* error);
360 // StreamAdapterInterface Interface
361 virtual StreamResult Read(void* buffer, size_t buffer_len,
362 size_t* read, int* error);
363 virtual StreamResult Write(const void* data, size_t data_len,
364 size_t* written, int* error);
367 scoped_ptr<StreamInterface> tap_;
368 StreamResult tap_result_;
370 DISALLOW_EVIL_CONSTRUCTORS(StreamTap);
373 ///////////////////////////////////////////////////////////////////////////////
374 // StreamSegment adapts a read stream, to expose a subset of the adapted
375 // stream's data. This is useful for cases where a stream contains multiple
376 // documents concatenated together. StreamSegment can expose a subset of
377 // the data as an independent stream, including support for rewinding and
379 ///////////////////////////////////////////////////////////////////////////////
381 class StreamSegment : public StreamAdapterInterface {
383 // The current position of the adapted stream becomes the beginning of the
384 // segment. If a length is specified, it bounds the length of the segment.
385 explicit StreamSegment(StreamInterface* stream);
386 explicit StreamSegment(StreamInterface* stream, size_t length);
388 // StreamAdapterInterface Interface
389 virtual StreamResult Read(void* buffer, size_t buffer_len,
390 size_t* read, int* error);
391 virtual bool SetPosition(size_t position);
392 virtual bool GetPosition(size_t* position) const;
393 virtual bool GetSize(size_t* size) const;
394 virtual bool GetAvailable(size_t* size) const;
397 size_t start_, pos_, length_;
398 DISALLOW_EVIL_CONSTRUCTORS(StreamSegment);
401 ///////////////////////////////////////////////////////////////////////////////
402 // NullStream gives errors on read, and silently discards all written data.
403 ///////////////////////////////////////////////////////////////////////////////
405 class NullStream : public StreamInterface {
408 virtual ~NullStream();
410 // StreamInterface Interface
411 virtual StreamState GetState() const;
412 virtual StreamResult Read(void* buffer, size_t buffer_len,
413 size_t* read, int* error);
414 virtual StreamResult Write(const void* data, size_t data_len,
415 size_t* written, int* error);
416 virtual void Close();
419 ///////////////////////////////////////////////////////////////////////////////
420 // FileStream is a simple implementation of a StreamInterface, which does not
421 // support asynchronous notification.
422 ///////////////////////////////////////////////////////////////////////////////
424 class FileStream : public StreamInterface {
427 virtual ~FileStream();
429 // The semantics of filename and mode are the same as stdio's fopen
430 virtual bool Open(const std::string& filename, const char* mode, int* error);
431 virtual bool OpenShare(const std::string& filename, const char* mode,
432 int shflag, int* error);
434 // By default, reads and writes are buffered for efficiency. Disabling
435 // buffering causes writes to block until the bytes on disk are updated.
436 virtual bool DisableBuffering();
438 virtual StreamState GetState() const;
439 virtual StreamResult Read(void* buffer, size_t buffer_len,
440 size_t* read, int* error);
441 virtual StreamResult Write(const void* data, size_t data_len,
442 size_t* written, int* error);
443 virtual void Close();
444 virtual bool SetPosition(size_t position);
445 virtual bool GetPosition(size_t* position) const;
446 virtual bool GetSize(size_t* size) const;
447 virtual bool GetAvailable(size_t* size) const;
448 virtual bool ReserveSize(size_t size);
450 virtual bool Flush();
453 // Tries to aquire an exclusive lock on the file.
454 // Use OpenShare(...) on win32 to get similar functionality.
459 // Note: Deprecated in favor of Filesystem::GetFileSize().
460 static bool GetSize(const std::string& filename, size_t* size);
463 virtual void DoClose();
468 DISALLOW_EVIL_CONSTRUCTORS(FileStream);
471 // A stream that caps the output at a certain size, dropping content from the
472 // middle of the logical stream and maintaining equal parts of the start/end of
473 // the logical stream.
474 class CircularFileStream : public FileStream {
476 explicit CircularFileStream(size_t max_size);
478 virtual bool Open(const std::string& filename, const char* mode, int* error);
479 virtual StreamResult Read(void* buffer, size_t buffer_len,
480 size_t* read, int* error);
481 virtual StreamResult Write(const void* data, size_t data_len,
482 size_t* written, int* error);
486 READ_MARKED, // Read 0 .. marked_position_
487 READ_MIDDLE, // Read position_ .. file_size
488 READ_LATEST, // Read marked_position_ .. position_ if the buffer was
489 // overwritten or 0 .. position_ otherwise.
492 size_t max_write_size_;
494 size_t marked_position_;
495 size_t last_write_position_;
496 ReadSegment read_segment_;
497 size_t read_segment_available_;
501 // A stream which pushes writes onto a separate thread and
502 // returns from the write call immediately.
503 class AsyncWriteStream : public StreamInterface {
505 // Takes ownership of the stream, but not the thread.
506 AsyncWriteStream(StreamInterface* stream, talk_base::Thread* write_thread)
508 write_thread_(write_thread),
509 state_(stream ? stream->GetState() : SS_CLOSED) {
512 virtual ~AsyncWriteStream();
514 // StreamInterface Interface
515 virtual StreamState GetState() const { return state_; }
516 // This is needed by some stream writers, such as RtpDumpWriter.
517 virtual bool GetPosition(size_t* position) const;
518 virtual StreamResult Read(void* buffer, size_t buffer_len,
519 size_t* read, int* error);
520 virtual StreamResult Write(const void* data, size_t data_len,
521 size_t* written, int* error);
522 virtual void Close();
523 virtual bool Flush();
526 // From MessageHandler
527 virtual void OnMessage(talk_base::Message* pmsg);
528 virtual void ClearBufferAndWrite();
531 talk_base::scoped_ptr<StreamInterface> stream_;
532 Thread* write_thread_;
535 mutable CriticalSection crit_stream_;
536 CriticalSection crit_buffer_;
538 DISALLOW_EVIL_CONSTRUCTORS(AsyncWriteStream);
543 // A FileStream that is actually not a file, but the output or input of a
544 // sub-command. See "man 3 popen" for documentation of the underlying OS popen()
546 class POpenStream : public FileStream {
548 POpenStream() : wait_status_(-1) {}
549 virtual ~POpenStream();
551 virtual bool Open(const std::string& subcommand, const char* mode,
553 // Same as Open(). shflag is ignored.
554 virtual bool OpenShare(const std::string& subcommand, const char* mode,
555 int shflag, int* error);
557 // Returns the wait status from the last Close() of an Open()'ed stream, or
558 // -1 if no Open()+Close() has been done on this object. Meaning of the number
559 // is documented in "man 2 wait".
560 int GetWaitStatus() const { return wait_status_; }
563 virtual void DoClose();
570 ///////////////////////////////////////////////////////////////////////////////
571 // MemoryStream is a simple implementation of a StreamInterface over in-memory
572 // data. Data is read and written at the current seek position. Reads return
573 // end-of-stream when they reach the end of data. Writes actually extend the
575 ///////////////////////////////////////////////////////////////////////////////
577 class MemoryStreamBase : public StreamInterface {
579 virtual StreamState GetState() const;
580 virtual StreamResult Read(void* buffer, size_t bytes, size_t* bytes_read,
582 virtual StreamResult Write(const void* buffer, size_t bytes,
583 size_t* bytes_written, int* error);
584 virtual void Close();
585 virtual bool SetPosition(size_t position);
586 virtual bool GetPosition(size_t* position) const;
587 virtual bool GetSize(size_t* size) const;
588 virtual bool GetAvailable(size_t* size) const;
589 virtual bool ReserveSize(size_t size);
591 char* GetBuffer() { return buffer_; }
592 const char* GetBuffer() const { return buffer_; }
597 virtual StreamResult DoReserve(size_t size, int* error);
599 // Invariant: 0 <= seek_position <= data_length_ <= buffer_length_
601 size_t buffer_length_;
603 size_t seek_position_;
606 DISALLOW_EVIL_CONSTRUCTORS(MemoryStreamBase);
609 // MemoryStream dynamically resizes to accomodate written data.
611 class MemoryStream : public MemoryStreamBase {
614 explicit MemoryStream(const char* data); // Calls SetData(data, strlen(data))
615 MemoryStream(const void* data, size_t length); // Calls SetData(data, length)
616 virtual ~MemoryStream();
618 void SetData(const void* data, size_t length);
621 virtual StreamResult DoReserve(size_t size, int* error);
622 // Memory Streams are aligned for efficiency.
623 static const int kAlignment = 16;
627 // ExternalMemoryStream adapts an external memory buffer, so writes which would
628 // extend past the end of the buffer will return end-of-stream.
630 class ExternalMemoryStream : public MemoryStreamBase {
632 ExternalMemoryStream();
633 ExternalMemoryStream(void* data, size_t length);
634 virtual ~ExternalMemoryStream();
636 void SetData(void* data, size_t length);
639 // FifoBuffer allows for efficient, thread-safe buffering of data between
640 // writer and reader. As the data can wrap around the end of the buffer,
641 // MemoryStreamBase can't help us here.
643 class FifoBuffer : public StreamInterface {
645 // Creates a FIFO buffer with the specified capacity.
646 explicit FifoBuffer(size_t length);
647 // Creates a FIFO buffer with the specified capacity and owner
648 FifoBuffer(size_t length, Thread* owner);
649 virtual ~FifoBuffer();
650 // Gets the amount of data currently readable from the buffer.
651 bool GetBuffered(size_t* data_len) const;
652 // Resizes the buffer to the specified capacity. Fails if data_length_ > size
653 bool SetCapacity(size_t length);
655 // Read into |buffer| with an offset from the current read position, offset
656 // is specified in number of bytes.
657 // This method doesn't adjust read position nor the number of available
658 // bytes, user has to call ConsumeReadData() to do this.
659 StreamResult ReadOffset(void* buffer, size_t bytes, size_t offset,
662 // Write |buffer| with an offset from the current write position, offset is
663 // specified in number of bytes.
664 // This method doesn't adjust the number of buffered bytes, user has to call
665 // ConsumeWriteBuffer() to do this.
666 StreamResult WriteOffset(const void* buffer, size_t bytes, size_t offset,
667 size_t* bytes_written);
669 // StreamInterface methods
670 virtual StreamState GetState() const;
671 virtual StreamResult Read(void* buffer, size_t bytes,
672 size_t* bytes_read, int* error);
673 virtual StreamResult Write(const void* buffer, size_t bytes,
674 size_t* bytes_written, int* error);
675 virtual void Close();
676 virtual const void* GetReadData(size_t* data_len);
677 virtual void ConsumeReadData(size_t used);
678 virtual void* GetWriteBuffer(size_t* buf_len);
679 virtual void ConsumeWriteBuffer(size_t used);
680 virtual bool GetWriteRemaining(size_t* size) const;
683 // Helper method that implements ReadOffset. Caller must acquire a lock
684 // when calling this method.
685 StreamResult ReadOffsetLocked(void* buffer, size_t bytes, size_t offset,
688 // Helper method that implements WriteOffset. Caller must acquire a lock
689 // when calling this method.
690 StreamResult WriteOffsetLocked(const void* buffer, size_t bytes,
691 size_t offset, size_t* bytes_written);
693 StreamState state_; // keeps the opened/closed state of the stream
694 scoped_ptr<char[]> buffer_; // the allocated buffer
695 size_t buffer_length_; // size of the allocated buffer
696 size_t data_length_; // amount of readable data in the buffer
697 size_t read_position_; // offset to the readable data
698 Thread* owner_; // stream callbacks are dispatched on this thread
699 mutable CriticalSection crit_; // object lock
700 DISALLOW_EVIL_CONSTRUCTORS(FifoBuffer);
703 ///////////////////////////////////////////////////////////////////////////////
705 class LoggingAdapter : public StreamAdapterInterface {
707 LoggingAdapter(StreamInterface* stream, LoggingSeverity level,
708 const std::string& label, bool hex_mode = false);
710 void set_label(const std::string& label);
712 virtual StreamResult Read(void* buffer, size_t buffer_len,
713 size_t* read, int* error);
714 virtual StreamResult Write(const void* data, size_t data_len,
715 size_t* written, int* error);
716 virtual void Close();
719 virtual void OnEvent(StreamInterface* stream, int events, int err);
722 LoggingSeverity level_;
725 LogMultilineState lms_;
727 DISALLOW_EVIL_CONSTRUCTORS(LoggingAdapter);
730 ///////////////////////////////////////////////////////////////////////////////
731 // StringStream - Reads/Writes to an external std::string
732 ///////////////////////////////////////////////////////////////////////////////
734 class StringStream : public StreamInterface {
736 explicit StringStream(std::string& str);
737 explicit StringStream(const std::string& str);
739 virtual StreamState GetState() const;
740 virtual StreamResult Read(void* buffer, size_t buffer_len,
741 size_t* read, int* error);
742 virtual StreamResult Write(const void* data, size_t data_len,
743 size_t* written, int* error);
744 virtual void Close();
745 virtual bool SetPosition(size_t position);
746 virtual bool GetPosition(size_t* position) const;
747 virtual bool GetSize(size_t* size) const;
748 virtual bool GetAvailable(size_t* size) const;
749 virtual bool ReserveSize(size_t size);
757 ///////////////////////////////////////////////////////////////////////////////
758 // StreamReference - A reference counting stream adapter
759 ///////////////////////////////////////////////////////////////////////////////
761 // Keep in mind that the streams and adapters defined in this file are
762 // not thread-safe, so this has limited uses.
764 // A StreamRefCount holds the reference count and a pointer to the
765 // wrapped stream. It deletes the wrapped stream when there are no
766 // more references. We can then have multiple StreamReference
767 // instances pointing to one StreamRefCount, all wrapping the same
770 class StreamReference : public StreamAdapterInterface {
771 class StreamRefCount;
773 // Constructor for the first reference to a stream
774 // Note: get more references through NewReference(). Use this
775 // constructor only once on a given stream.
776 explicit StreamReference(StreamInterface* stream);
777 StreamInterface* GetStream() { return stream(); }
778 StreamInterface* NewReference();
779 virtual ~StreamReference();
782 class StreamRefCount {
784 explicit StreamRefCount(StreamInterface* stream)
785 : stream_(stream), ref_count_(1) {
787 void AddReference() {
788 CritScope lock(&cs_);
793 { // Atomic ops would have been a better fit here.
794 CritScope lock(&cs_);
795 ref_count = --ref_count_;
797 if (ref_count == 0) {
803 StreamInterface* stream_;
806 DISALLOW_EVIL_CONSTRUCTORS(StreamRefCount);
809 // Constructor for adding references
810 explicit StreamReference(StreamRefCount* stream_ref_count,
811 StreamInterface* stream);
813 StreamRefCount* stream_ref_count_;
814 DISALLOW_EVIL_CONSTRUCTORS(StreamReference);
817 ///////////////////////////////////////////////////////////////////////////////
819 // Flow attempts to move bytes from source to sink via buffer of size
820 // buffer_len. The function returns SR_SUCCESS when source reaches
821 // end-of-stream (returns SR_EOS), and all the data has been written successful
822 // to sink. Alternately, if source returns SR_BLOCK or SR_ERROR, or if sink
823 // returns SR_BLOCK, SR_ERROR, or SR_EOS, then the function immediately returns
824 // with the unexpected StreamResult value.
825 // data_len is the length of the valid data in buffer. in case of error
826 // this is the data that read from source but can't move to destination.
827 // as a pass in parameter, it indicates data in buffer that should move to sink
828 StreamResult Flow(StreamInterface* source,
829 char* buffer, size_t buffer_len,
830 StreamInterface* sink, size_t* data_len = NULL);
832 ///////////////////////////////////////////////////////////////////////////////
834 } // namespace talk_base
836 #endif // TALK_BASE_STREAM_H_