1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
// Copyright (c) 2012 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 NET_SPDY_SPDY_FRAME_BUILDER_H_
#define NET_SPDY_SPDY_FRAME_BUILDER_H_
#include <string>
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "base/strings/string_piece.h"
#include "base/sys_byteorder.h"
#include "net/base/net_export.h"
#include "net/spdy/spdy_protocol.h"
namespace net {
class SpdyFramer;
// This class provides facilities for basic binary value packing
// into Spdy frames.
//
// The SpdyFrameBuilder supports appending primitive values (int, string, etc)
// to a frame instance. The SpdyFrameBuilder grows its internal memory buffer
// dynamically to hold the sequence of primitive values. The internal memory
// buffer is exposed as the "data" of the SpdyFrameBuilder.
class NET_EXPORT_PRIVATE SpdyFrameBuilder {
public:
// Initializes a SpdyFrameBuilder with a buffer of given size
explicit SpdyFrameBuilder(size_t size);
~SpdyFrameBuilder();
// Returns the size of the SpdyFrameBuilder's data.
size_t length() const { return length_; }
// Returns a writeable buffer of given size in bytes, to be appended to the
// currently written frame. Does bounds checking on length but does not
// increment the underlying iterator. To do so, consumers should subsequently
// call Seek().
// In general, consumers should use Write*() calls instead of this.
// Returns NULL on failure.
char* GetWritableBuffer(size_t length);
// Seeks forward by the given number of bytes. Useful in conjunction with
// GetWriteableBuffer() above.
bool Seek(size_t length);
// Populates this frame with a SPDY control frame header using
// version-specific information from the |framer| and length information from
// capacity_. The given type must be a control frame type.
// Used only for SPDY versions <4.
bool WriteControlFrameHeader(const SpdyFramer& framer,
SpdyFrameType type,
uint8 flags);
// Populates this frame with a SPDY data frame header using version-specific
// information from the |framer| and length information from capacity_.
bool WriteDataFrameHeader(const SpdyFramer& framer,
SpdyStreamId stream_id,
SpdyDataFlags flags);
// Populates this frame with a SPDY4/HTTP2 frame prefix using
// version-specific information from the |framer| and length information from
// capacity_. The given type must be a control frame type.
// Used only for SPDY versions >=4.
bool WriteFramePrefix(const SpdyFramer& framer,
SpdyFrameType type,
uint8 flags,
SpdyStreamId stream_id);
// Takes the buffer from the SpdyFrameBuilder.
SpdyFrame* take() {
SpdyFrame* rv = new SpdyFrame(buffer_.release(), length_, true);
capacity_ = 0;
length_ = 0;
return rv;
}
// Methods for adding to the payload. These values are appended to the end
// of the SpdyFrameBuilder payload. Note - binary integers are converted from
// host to network form.
bool WriteUInt8(uint8 value) {
return WriteBytes(&value, sizeof(value));
}
bool WriteUInt16(uint16 value) {
value = htons(value);
return WriteBytes(&value, sizeof(value));
}
bool WriteUInt32(uint32 value) {
value = htonl(value);
return WriteBytes(&value, sizeof(value));
}
// TODO(hkhalil) Rename to WriteStringPiece16().
bool WriteString(const std::string& value);
bool WriteStringPiece32(const base::StringPiece& value);
bool WriteBytes(const void* data, uint32 data_len);
// Update (in-place) the length field in the frame being built to reflect the
// current actual length of bytes written to said frame through this builder.
// The framer parameter is used to determine version-specific location and
// size information of the length field to be written, and must be initialized
// with the correct version for the frame being written.
bool RewriteLength(const SpdyFramer& framer);
// Update (in-place) the length field in the frame being built to reflect the
// given length.
// The framer parameter is used to determine version-specific location and
// size information of the length field to be written, and must be initialized
// with the correct version for the frame being written.
bool OverwriteLength(const SpdyFramer& framer, size_t length);
private:
// Checks to make sure that there is an appropriate amount of space for a
// write of given size, in bytes.
bool CanWrite(size_t length) const;
scoped_ptr<char[]> buffer_;
size_t capacity_; // Allocation size of payload, set by constructor.
size_t length_; // Current length of the buffer.
};
} // namespace net
#endif // NET_SPDY_SPDY_FRAME_BUILDER_H_
|
