Move webrtc/{base => rtc_base}

webrtc/base/stream.h

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_BASE_STREAM_H_
 #define WEBRTC_BASE_STREAM_H_
 
-#include <stdio.h>
 
-#include <memory>
-
-#include "webrtc/base/buffer.h"
-#include "webrtc/base/constructormagic.h"
-#include "webrtc/base/criticalsection.h"
-#include "webrtc/base/logging.h"
-#include "webrtc/base/messagehandler.h"
-#include "webrtc/base/messagequeue.h"
-#include "webrtc/base/sigslot.h"
-
-namespace rtc {
-
-///////////////////////////////////////////////////////////////////////////////
-// StreamInterface is a generic asynchronous stream interface, supporting read,
-// write, and close operations, and asynchronous signalling of state changes.
-// The interface is designed with file, memory, and socket implementations in
-// mind.  Some implementations offer extended operations, such as seeking.
-///////////////////////////////////////////////////////////////////////////////
-
-// The following enumerations are declared outside of the StreamInterface
-// class for brevity in use.
-
-// The SS_OPENING state indicates that the stream will signal open or closed
-// in the future.
-enum StreamState { SS_CLOSED, SS_OPENING, SS_OPEN };
-
-// Stream read/write methods return this value to indicate various success
-// and failure conditions described below.
-enum StreamResult { SR_ERROR, SR_SUCCESS, SR_BLOCK, SR_EOS };
-
-// StreamEvents are used to asynchronously signal state transitionss.  The flags
-// may be combined.
-//  SE_OPEN: The stream has transitioned to the SS_OPEN state
-//  SE_CLOSE: The stream has transitioned to the SS_CLOSED state
-//  SE_READ: Data is available, so Read is likely to not return SR_BLOCK
-//  SE_WRITE: Data can be written, so Write is likely to not return SR_BLOCK
-enum StreamEvent { SE_OPEN = 1, SE_READ = 2, SE_WRITE = 4, SE_CLOSE = 8 };
-
-class Thread;
-
-struct StreamEventData : public MessageData {
-  int events, error;
-  StreamEventData(int ev, int er) : events(ev), error(er) { }
-};
-
-class StreamInterface : public MessageHandler {
- public:
-  enum {
-    MSG_POST_EVENT = 0xF1F1, MSG_MAX = MSG_POST_EVENT
-  };
-
-  ~StreamInterface() override;
-
-  virtual StreamState GetState() const = 0;
-
-  // Read attempts to fill buffer of size buffer_len.  Write attempts to send
-  // data_len bytes stored in data.  The variables read and write are set only
-  // on SR_SUCCESS (see below).  Likewise, error is only set on SR_ERROR.
-  // Read and Write return a value indicating:
-  //  SR_ERROR: an error occurred, which is returned in a non-null error
-  //    argument.  Interpretation of the error requires knowledge of the
-  //    stream's concrete type, which limits its usefulness.
-  //  SR_SUCCESS: some number of bytes were successfully written, which is
-  //    returned in a non-null read/write argument.
-  //  SR_BLOCK: the stream is in non-blocking mode, and the operation would
-  //    block, or the stream is in SS_OPENING state.
-  //  SR_EOS: the end-of-stream has been reached, or the stream is in the
-  //    SS_CLOSED state.
-  virtual StreamResult Read(void* buffer, size_t buffer_len,
-                            size_t* read, int* error) = 0;
-  virtual StreamResult Write(const void* data, size_t data_len,
-                             size_t* written, int* error) = 0;
-  // Attempt to transition to the SS_CLOSED state.  SE_CLOSE will not be
-  // signalled as a result of this call.
-  virtual void Close() = 0;
-
-  // Streams may signal one or more StreamEvents to indicate state changes.
-  // The first argument identifies the stream on which the state change occured.
-  // The second argument is a bit-wise combination of StreamEvents.
-  // If SE_CLOSE is signalled, then the third argument is the associated error
-  // code.  Otherwise, the value is undefined.
-  // Note: Not all streams will support asynchronous event signalling.  However,
-  // SS_OPENING and SR_BLOCK returned from stream member functions imply that
-  // certain events will be raised in the future.
-  sigslot::signal3<StreamInterface*, int, int> SignalEvent;
-
-  // Like calling SignalEvent, but posts a message to the specified thread,
-  // which will call SignalEvent.  This helps unroll the stack and prevent
-  // re-entrancy.
-  void PostEvent(Thread* t, int events, int err);
-  // Like the aforementioned method, but posts to the current thread.
-  void PostEvent(int events, int err);
-
-  //
-  // OPTIONAL OPERATIONS
-  //
-  // Not all implementations will support the following operations.  In general,
-  // a stream will only support an operation if it reasonably efficient to do
-  // so.  For example, while a socket could buffer incoming data to support
-  // seeking, it will not do so.  Instead, a buffering stream adapter should
-  // be used.
-  //
-  // Even though several of these operations are related, you should
-  // always use whichever operation is most relevant.  For example, you may
-  // be tempted to use GetSize() and GetPosition() to deduce the result of
-  // GetAvailable().  However, a stream which is read-once may support the
-  // latter operation but not the former.
-  //
-
-  // The following four methods are used to avoid copying data multiple times.
-
-  // GetReadData returns a pointer to a buffer which is owned by the stream.
-  // The buffer contains data_len bytes.  null is returned if no data is
-  // available, or if the method fails.  If the caller processes the data, it
-  // must call ConsumeReadData with the number of processed bytes.  GetReadData
-  // does not require a matching call to ConsumeReadData if the data is not
-  // processed.  Read and ConsumeReadData invalidate the buffer returned by
-  // GetReadData.
-  virtual const void* GetReadData(size_t* data_len);
-  virtual void ConsumeReadData(size_t used) {}
-
-  // GetWriteBuffer returns a pointer to a buffer which is owned by the stream.
-  // The buffer has a capacity of buf_len bytes.  null is returned if there is
-  // no buffer available, or if the method fails.  The call may write data to
-  // the buffer, and then call ConsumeWriteBuffer with the number of bytes
-  // written.  GetWriteBuffer does not require a matching call to
-  // ConsumeWriteData if no data is written.  Write, ForceWrite, and
-  // ConsumeWriteData invalidate the buffer returned by GetWriteBuffer.
-  // TODO: Allow the caller to specify a minimum buffer size.  If the specified
-  // amount of buffer is not yet available, return null and Signal SE_WRITE
-  // when it is available.  If the requested amount is too large, return an
-  // error.
-  virtual void* GetWriteBuffer(size_t* buf_len);
-  virtual void ConsumeWriteBuffer(size_t used) {}
-
-  // Write data_len bytes found in data, circumventing any throttling which
-  // would could cause SR_BLOCK to be returned.  Returns true if all the data
-  // was written.  Otherwise, the method is unsupported, or an unrecoverable
-  // error occurred, and the error value is set.  This method should be used
-  // sparingly to write critical data which should not be throttled.  A stream
-  // which cannot circumvent its blocking constraints should not implement this
-  // method.
-  // NOTE: This interface is being considered experimentally at the moment.  It
-  // would be used by JUDP and BandwidthStream as a way to circumvent certain
-  // soft limits in writing.
-  //virtual bool ForceWrite(const void* data, size_t data_len, int* error) {
-  //  if (error) *error = -1;
-  //  return false;
-  //}
-
-  // Seek to a byte offset from the beginning of the stream.  Returns false if
-  // the stream does not support seeking, or cannot seek to the specified
-  // position.
-  virtual bool SetPosition(size_t position);
-
-  // Get the byte offset of the current position from the start of the stream.
-  // Returns false if the position is not known.
-  virtual bool GetPosition(size_t* position) const;
-
-  // Get the byte length of the entire stream.  Returns false if the length
-  // is not known.
-  virtual bool GetSize(size_t* size) const;
-
-  // Return the number of Read()-able bytes remaining before end-of-stream.
-  // Returns false if not known.
-  virtual bool GetAvailable(size_t* size) const;
-
-  // Return the number of Write()-able bytes remaining before end-of-stream.
-  // Returns false if not known.
-  virtual bool GetWriteRemaining(size_t* size) const;
-
-  // Return true if flush is successful.
-  virtual bool Flush();
-
-  // Communicates the amount of data which will be written to the stream.  The
-  // stream may choose to preallocate memory to accomodate this data.  The
-  // stream may return false to indicate that there is not enough room (ie,
-  // Write will return SR_EOS/SR_ERROR at some point).  Note that calling this
-  // function should not affect the existing state of data in the stream.
-  virtual bool ReserveSize(size_t size);
-
-  //
-  // CONVENIENCE METHODS
-  //
-  // These methods are implemented in terms of other methods, for convenience.
-  //
-
-  // Seek to the start of the stream.
-  inline bool Rewind() { return SetPosition(0); }
-
-  // WriteAll is a helper function which repeatedly calls Write until all the
-  // data is written, or something other than SR_SUCCESS is returned.  Note that
-  // unlike Write, the argument 'written' is always set, and may be non-zero
-  // on results other than SR_SUCCESS.  The remaining arguments have the
-  // same semantics as Write.
-  StreamResult WriteAll(const void* data, size_t data_len,
-                        size_t* written, int* error);
-
-  // Similar to ReadAll.  Calls Read until buffer_len bytes have been read, or
-  // until a non-SR_SUCCESS result is returned.  'read' is always set.
-  StreamResult ReadAll(void* buffer, size_t buffer_len,
-                       size_t* read, int* error);
-
-  // ReadLine is a helper function which repeatedly calls Read until it hits
-  // the end-of-line character, or something other than SR_SUCCESS.
-  // TODO: this is too inefficient to keep here.  Break this out into a buffered
-  // readline object or adapter
-  StreamResult ReadLine(std::string* line);
-
- protected:
-  StreamInterface();
-
-  // MessageHandler Interface
-  void OnMessage(Message* msg) override;
-
- private:
-  RTC_DISALLOW_COPY_AND_ASSIGN(StreamInterface);
-};
-
-///////////////////////////////////////////////////////////////////////////////
-// StreamAdapterInterface is a convenient base-class for adapting a stream.
-// By default, all operations are pass-through.  Override the methods that you
-// require adaptation.  Streams should really be upgraded to reference-counted.
-// In the meantime, use the owned flag to indicate whether the adapter should
-// own the adapted stream.
-///////////////////////////////////////////////////////////////////////////////
-
-class StreamAdapterInterface : public StreamInterface,
-                               public sigslot::has_slots<> {
- public:
-  explicit StreamAdapterInterface(StreamInterface* stream, bool owned = true);
-
-  // Core Stream Interface
-  StreamState GetState() const override;
-  StreamResult Read(void* buffer,
-                    size_t buffer_len,
-                    size_t* read,
-                    int* error) override;
-  StreamResult Write(const void* data,
-                     size_t data_len,
-                     size_t* written,
-                     int* error) override;
-  void Close() override;
-
-  // Optional Stream Interface
-  /*  Note: Many stream adapters were implemented prior to this Read/Write
-      interface.  Therefore, a simple pass through of data in those cases may
-      be broken.  At a later time, we should do a once-over pass of all
-      adapters, and make them compliant with these interfaces, after which this
-      code can be uncommented.
-  virtual const void* GetReadData(size_t* data_len) {
-    return stream_->GetReadData(data_len);
-  }
-  virtual void ConsumeReadData(size_t used) {
-    stream_->ConsumeReadData(used);
-  }
-
-  virtual void* GetWriteBuffer(size_t* buf_len) {
-    return stream_->GetWriteBuffer(buf_len);
-  }
-  virtual void ConsumeWriteBuffer(size_t used) {
-    stream_->ConsumeWriteBuffer(used);
-  }
-  */
-
-  /*  Note: This interface is currently undergoing evaluation.
-  virtual bool ForceWrite(const void* data, size_t data_len, int* error) {
-    return stream_->ForceWrite(data, data_len, error);
-  }
-  */
-
-  bool SetPosition(size_t position) override;
-  bool GetPosition(size_t* position) const override;
-  bool GetSize(size_t* size) const override;
-  bool GetAvailable(size_t* size) const override;
-  bool GetWriteRemaining(size_t* size) const override;
-  bool ReserveSize(size_t size) override;
-  bool Flush() override;
-
-  void Attach(StreamInterface* stream, bool owned = true);
-  StreamInterface* Detach();
-
- protected:
-  ~StreamAdapterInterface() override;
-
-  // Note that the adapter presents itself as the origin of the stream events,
-  // since users of the adapter may not recognize the adapted object.
-  virtual void OnEvent(StreamInterface* stream, int events, int err);
-  StreamInterface* stream() { return stream_; }
-
- private:
-  StreamInterface* stream_;
-  bool owned_;
-  RTC_DISALLOW_COPY_AND_ASSIGN(StreamAdapterInterface);
-};
-
-///////////////////////////////////////////////////////////////////////////////
-// StreamTap is a non-modifying, pass-through adapter, which copies all data
-// in either direction to the tap.  Note that errors or blocking on writing to
-// the tap will prevent further tap writes from occurring.
-///////////////////////////////////////////////////////////////////////////////
-
-class StreamTap : public StreamAdapterInterface {
- public:
-  explicit StreamTap(StreamInterface* stream, StreamInterface* tap);
-  ~StreamTap() override;
-
-  void AttachTap(StreamInterface* tap);
-  StreamInterface* DetachTap();
-  StreamResult GetTapResult(int* error);
-
-  // StreamAdapterInterface Interface
-  StreamResult Read(void* buffer,
-                    size_t buffer_len,
-                    size_t* read,
-                    int* error) override;
-  StreamResult Write(const void* data,
-                     size_t data_len,
-                     size_t* written,
-                     int* error) override;
-
- private:
-  std::unique_ptr<StreamInterface> tap_;
-  StreamResult tap_result_;
-  int tap_error_;
-  RTC_DISALLOW_COPY_AND_ASSIGN(StreamTap);
-};
-
-///////////////////////////////////////////////////////////////////////////////
-// NullStream gives errors on read, and silently discards all written data.
-///////////////////////////////////////////////////////////////////////////////
-
-class NullStream : public StreamInterface {
- public:
-  NullStream();
-  ~NullStream() override;
-
-  // StreamInterface Interface
-  StreamState GetState() const override;
-  StreamResult Read(void* buffer,
-                    size_t buffer_len,
-                    size_t* read,
-                    int* error) override;
-  StreamResult Write(const void* data,
-                     size_t data_len,
-                     size_t* written,
-                     int* error) override;
-  void Close() override;
-};
-
-///////////////////////////////////////////////////////////////////////////////
-// FileStream is a simple implementation of a StreamInterface, which does not
-// support asynchronous notification.
-///////////////////////////////////////////////////////////////////////////////
-
-class FileStream : public StreamInterface {
- public:
-  FileStream();
-  ~FileStream() override;
-
-  // The semantics of filename and mode are the same as stdio's fopen
-  virtual bool Open(const std::string& filename, const char* mode, int* error);
-  virtual bool OpenShare(const std::string& filename, const char* mode,
-                         int shflag, int* error);
-
-  // By default, reads and writes are buffered for efficiency.  Disabling
-  // buffering causes writes to block until the bytes on disk are updated.
-  virtual bool DisableBuffering();
-
-  StreamState GetState() const override;
-  StreamResult Read(void* buffer,
-                    size_t buffer_len,
-                    size_t* read,
-                    int* error) override;
-  StreamResult Write(const void* data,
-                     size_t data_len,
-                     size_t* written,
-                     int* error) override;
-  void Close() override;
-  bool SetPosition(size_t position) override;
-  bool GetPosition(size_t* position) const override;
-  bool GetSize(size_t* size) const override;
-  bool GetAvailable(size_t* size) const override;
-  bool ReserveSize(size_t size) override;
-
-  bool Flush() override;
-
-#if defined(WEBRTC_POSIX) && !defined(__native_client__)
-  // Tries to aquire an exclusive lock on the file.
-  // Use OpenShare(...) on win32 to get similar functionality.
-  bool TryLock();
-  bool Unlock();
-#endif
-
-  // Note: Deprecated in favor of Filesystem::GetFileSize().
-  static bool GetSize(const std::string& filename, size_t* size);
-
- protected:
-  virtual void DoClose();
-
-  FILE* file_;
-
- private:
-  RTC_DISALLOW_COPY_AND_ASSIGN(FileStream);
-};
-
-///////////////////////////////////////////////////////////////////////////////
-// MemoryStream is a simple implementation of a StreamInterface over in-memory
-// data.  Data is read and written at the current seek position.  Reads return
-// end-of-stream when they reach the end of data.  Writes actually extend the
-// end of data mark.
-///////////////////////////////////////////////////////////////////////////////
-
-class MemoryStreamBase : public StreamInterface {
- public:
-  StreamState GetState() const override;
-  StreamResult Read(void* buffer,
-                    size_t bytes,
-                    size_t* bytes_read,
-                    int* error) override;
-  StreamResult Write(const void* buffer,
-                     size_t bytes,
-                     size_t* bytes_written,
-                     int* error) override;
-  void Close() override;
-  bool SetPosition(size_t position) override;
-  bool GetPosition(size_t* position) const override;
-  bool GetSize(size_t* size) const override;
-  bool GetAvailable(size_t* size) const override;
-  bool ReserveSize(size_t size) override;
-
-  char* GetBuffer() { return buffer_; }
-  const char* GetBuffer() const { return buffer_; }
-
- protected:
-  MemoryStreamBase();
-
-  virtual StreamResult DoReserve(size_t size, int* error);
-
-  // Invariant: 0 <= seek_position <= data_length_ <= buffer_length_
-  char* buffer_;
-  size_t buffer_length_;
-  size_t data_length_;
-  size_t seek_position_;
-
- private:
-  RTC_DISALLOW_COPY_AND_ASSIGN(MemoryStreamBase);
-};
-
-// MemoryStream dynamically resizes to accomodate written data.
-
-class MemoryStream : public MemoryStreamBase {
- public:
-  MemoryStream();
-  explicit MemoryStream(const char* data);  // Calls SetData(data, strlen(data))
-  MemoryStream(const void* data, size_t length);  // Calls SetData(data, length)
-  ~MemoryStream() override;
-
-  void SetData(const void* data, size_t length);
-
- protected:
-  StreamResult DoReserve(size_t size, int* error) override;
-  // Memory Streams are aligned for efficiency.
-  static const int kAlignment = 16;
-  char* buffer_alloc_;
-};
-
-// ExternalMemoryStream adapts an external memory buffer, so writes which would
-// extend past the end of the buffer will return end-of-stream.
-
-class ExternalMemoryStream : public MemoryStreamBase {
- public:
-  ExternalMemoryStream();
-  ExternalMemoryStream(void* data, size_t length);
-  ~ExternalMemoryStream() override;
-
-  void SetData(void* data, size_t length);
-};
-
-// FifoBuffer allows for efficient, thread-safe buffering of data between
-// writer and reader. As the data can wrap around the end of the buffer,
-// MemoryStreamBase can't help us here.
-
-class FifoBuffer : public StreamInterface {
- public:
-  // Creates a FIFO buffer with the specified capacity.
-  explicit FifoBuffer(size_t length);
-  // Creates a FIFO buffer with the specified capacity and owner
-  FifoBuffer(size_t length, Thread* owner);
-  ~FifoBuffer() override;
-  // Gets the amount of data currently readable from the buffer.
-  bool GetBuffered(size_t* data_len) const;
-  // Resizes the buffer to the specified capacity. Fails if data_length_ > size
-  bool SetCapacity(size_t length);
-
-  // Read into |buffer| with an offset from the current read position, offset
-  // is specified in number of bytes.
-  // This method doesn't adjust read position nor the number of available
-  // bytes, user has to call ConsumeReadData() to do this.
-  StreamResult ReadOffset(void* buffer, size_t bytes, size_t offset,
-                          size_t* bytes_read);
-
-  // Write |buffer| with an offset from the current write position, offset is
-  // specified in number of bytes.
-  // This method doesn't adjust the number of buffered bytes, user has to call
-  // ConsumeWriteBuffer() to do this.
-  StreamResult WriteOffset(const void* buffer, size_t bytes, size_t offset,
-                           size_t* bytes_written);
-
-  // StreamInterface methods
-  StreamState GetState() const override;
-  StreamResult Read(void* buffer,
-                    size_t bytes,
-                    size_t* bytes_read,
-                    int* error) override;
-  StreamResult Write(const void* buffer,
-                     size_t bytes,
-                     size_t* bytes_written,
-                     int* error) override;
-  void Close() override;
-  const void* GetReadData(size_t* data_len) override;
-  void ConsumeReadData(size_t used) override;
-  void* GetWriteBuffer(size_t* buf_len) override;
-  void ConsumeWriteBuffer(size_t used) override;
-  bool GetWriteRemaining(size_t* size) const override;
-
- private:
-  // Helper method that implements ReadOffset. Caller must acquire a lock
-  // when calling this method.
-  StreamResult ReadOffsetLocked(void* buffer, size_t bytes, size_t offset,
-                                size_t* bytes_read)
-      EXCLUSIVE_LOCKS_REQUIRED(crit_);
-
-  // Helper method that implements WriteOffset. Caller must acquire a lock
-  // when calling this method.
-  StreamResult WriteOffsetLocked(const void* buffer, size_t bytes,
-                                 size_t offset, size_t* bytes_written)
-      EXCLUSIVE_LOCKS_REQUIRED(crit_);
-
-  // keeps the opened/closed state of the stream
-  StreamState state_ GUARDED_BY(crit_);
-  // the allocated buffer
-  std::unique_ptr<char[]> buffer_ GUARDED_BY(crit_);
-  // size of the allocated buffer
-  size_t buffer_length_ GUARDED_BY(crit_);
-  // amount of readable data in the buffer
-  size_t data_length_ GUARDED_BY(crit_);
-  // offset to the readable data
-  size_t read_position_ GUARDED_BY(crit_);
-  // stream callbacks are dispatched on this thread
-  Thread* owner_;
-  // object lock
-  CriticalSection crit_;
-  RTC_DISALLOW_COPY_AND_ASSIGN(FifoBuffer);
-};
-
-///////////////////////////////////////////////////////////////////////////////
-
-class LoggingAdapter : public StreamAdapterInterface {
- public:
-  LoggingAdapter(StreamInterface* stream, LoggingSeverity level,
-                 const std::string& label, bool hex_mode = false);
-
-  void set_label(const std::string& label);
-
-  StreamResult Read(void* buffer,
-                    size_t buffer_len,
-                    size_t* read,
-                    int* error) override;
-  StreamResult Write(const void* data,
-                     size_t data_len,
-                     size_t* written,
-                     int* error) override;
-  void Close() override;
-
- protected:
-  void OnEvent(StreamInterface* stream, int events, int err) override;
-
- private:
-  LoggingSeverity level_;
-  std::string label_;
-  bool hex_mode_;
-  LogMultilineState lms_;
-
-  RTC_DISALLOW_COPY_AND_ASSIGN(LoggingAdapter);
-};
-
-///////////////////////////////////////////////////////////////////////////////
-// StringStream - Reads/Writes to an external std::string
-///////////////////////////////////////////////////////////////////////////////
-
-class StringStream : public StreamInterface {
- public:
-  explicit StringStream(std::string* str);
-  explicit StringStream(const std::string& str);
-
-  StreamState GetState() const override;
-  StreamResult Read(void* buffer,
-                    size_t buffer_len,
-                    size_t* read,
-                    int* error) override;
-  StreamResult Write(const void* data,
-                     size_t data_len,
-                     size_t* written,
-                     int* error) override;
-  void Close() override;
-  bool SetPosition(size_t position) override;
-  bool GetPosition(size_t* position) const override;
-  bool GetSize(size_t* size) const override;
-  bool GetAvailable(size_t* size) const override;
-  bool ReserveSize(size_t size) override;
-
- private:
-  std::string& str_;
-  size_t read_pos_;
-  bool read_only_;
-};
-
-///////////////////////////////////////////////////////////////////////////////
-// StreamReference - A reference counting stream adapter
-///////////////////////////////////////////////////////////////////////////////
-
-// Keep in mind that the streams and adapters defined in this file are
-// not thread-safe, so this has limited uses.
-
-// A StreamRefCount holds the reference count and a pointer to the
-// wrapped stream. It deletes the wrapped stream when there are no
-// more references. We can then have multiple StreamReference
-// instances pointing to one StreamRefCount, all wrapping the same
-// stream.
-
-class StreamReference : public StreamAdapterInterface {
-  class StreamRefCount;
- public:
-  // Constructor for the first reference to a stream
-  // Note: get more references through NewReference(). Use this
-  // constructor only once on a given stream.
-  explicit StreamReference(StreamInterface* stream);
-  StreamInterface* GetStream() { return stream(); }
-  StreamInterface* NewReference();
-  ~StreamReference() override;
-
- private:
-  class StreamRefCount {
-   public:
-    explicit StreamRefCount(StreamInterface* stream)
-        : stream_(stream), ref_count_(1) {
-    }
-    void AddReference() {
-      CritScope lock(&cs_);
-      ++ref_count_;
-    }
-    void Release() {
-      int ref_count;
-      {  // Atomic ops would have been a better fit here.
-        CritScope lock(&cs_);
-        ref_count = --ref_count_;
-      }
-      if (ref_count == 0) {
-        delete stream_;
-        delete this;
-      }
-    }
-   private:
-    StreamInterface* stream_;
-    int ref_count_;
-    CriticalSection cs_;
-    RTC_DISALLOW_COPY_AND_ASSIGN(StreamRefCount);
-  };
-
-  // Constructor for adding references
-  explicit StreamReference(StreamRefCount* stream_ref_count,
-                           StreamInterface* stream);
-
-  StreamRefCount* stream_ref_count_;
-  RTC_DISALLOW_COPY_AND_ASSIGN(StreamReference);
-};
-
-///////////////////////////////////////////////////////////////////////////////
-
-// Flow attempts to move bytes from source to sink via buffer of size
-// buffer_len.  The function returns SR_SUCCESS when source reaches
-// end-of-stream (returns SR_EOS), and all the data has been written successful
-// to sink.  Alternately, if source returns SR_BLOCK or SR_ERROR, or if sink
-// returns SR_BLOCK, SR_ERROR, or SR_EOS, then the function immediately returns
-// with the unexpected StreamResult value.
-// data_len is the length of the valid data in buffer. in case of error
-// this is the data that read from source but can't move to destination.
-// as a pass in parameter, it indicates data in buffer that should move to sink
-StreamResult Flow(StreamInterface* source,
-                  char* buffer,
-                  size_t buffer_len,
-                  StreamInterface* sink,
-                  size_t* data_len = nullptr);
-
-///////////////////////////////////////////////////////////////////////////////
-
-}  // namespace rtc
+// This header is deprecated and is just left here temporarily during
+// refactoring. See https://bugs.webrtc.org/7634 for more details.
+#include "webrtc/rtc_base/stream.h"
 
 #endif  // WEBRTC_BASE_STREAM_H_