content/browser/loader/stream_writer.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_LOADER_STREAM_WRITER_H_
   6 #define CONTENT_BROWSER_LOADER_STREAM_WRITER_H_
   7
   8 #include "base/macros.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "content/browser/streams/stream_write_observer.h"
  11
  12 class GURL;
  13
  14 namespace net {
  15 class IOBuffer;
  16 }
  17
  18 namespace content {
  19
  20 class ResourceController;
  21 class Stream;
  22 class StreamRegistry;
  23
  24 // StreamWriter is a helper class for ResourceHandlers which route their output
  25 // into a Stream. It manages an internal buffer and handles back-pressure from
  26 // the Stream's reader.
  27 class StreamWriter : public StreamWriteObserver {
  28  public:
  29   // Creates a new StreamWriter without an initialized Stream or controller. The
  30   // controller must be set before the writer is used.
  31   StreamWriter();
  32   ~StreamWriter() override;
  33
  34   Stream* stream() { return stream_.get(); }
  35
  36   void set_controller(ResourceController* controller) {
  37     controller_ = controller;
  38   }
  39
  40   // When immediate mode is enabled, the |stream_| is flushed every time new
  41   // data is made available by calls to OnReadCompleted.
  42   void set_immediate_mode(bool enabled) { immediate_mode_ = enabled; }
  43
  44   // Initializes the writer with a new Stream in |registry|. |origin| will be
  45   // used to construct the URL for the Stream. See WebCore::BlobURL and and
  46   // WebCore::SecurityOrigin in Blink to understand how origin check is done on
  47   // resource loading.
  48   void InitializeStream(StreamRegistry* registry,
  49                         const GURL& origin);
  50
  51   // Prepares a buffer to read data from the request. This call will be followed
  52   // by either OnReadCompleted (on successful read or EOF) or destruction.  The
  53   // buffer may not be recycled until OnReadCompleted is called. If |min_size|
  54   // is not -1, it is the minimum size of the returned buffer.
  55   //
  56   // OnWillRead may be called before the stream is initialized. This is to
  57   // support MimeTypeResourceHandler which reads the initial chunk of data
  58   // early.
  59   void OnWillRead(scoped_refptr<net::IOBuffer>* buf,
  60                   int* buf_size,
  61                   int min_size);
  62
  63   // A read was completed, forward the data to the Stream. If |*defer| is set to
  64   // true, the implementation must not continue to process the request until
  65   // Resume is called on |controller_|.
  66   //
  67   // InitializeStream must have been called before calling OnReadCompleted.
  68   void OnReadCompleted(int bytes_read, bool* defer);
  69
  70   // Called when there is no more data to read to the stream.
  71   void Finalize();
  72
  73  private:
  74   // StreamWriteObserver implementation.
  75   void OnSpaceAvailable(Stream* stream) override;
  76   void OnClose(Stream* stream) override;
  77
  78   ResourceController* controller_;
  79   scoped_refptr<Stream> stream_;
  80   scoped_refptr<net::IOBuffer> read_buffer_;
  81   bool immediate_mode_;
  82
  83   DISALLOW_COPY_AND_ASSIGN(StreamWriter);
  84 };
  85
  86 }  // namespace content
  87
  88 #endif  // CONTENT_BROWSER_LOADER_STREAM_WRITER_H_