| // 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 <stddef.h> |
| #include <stdint.h> |
| |
| #include <memory> |
| #include <string> |
| |
| #include "base/strings/string_piece.h" |
| #include "base/sys_byteorder.h" |
| #include "net/base/net_export.h" |
| #include "net/spdy/spdy_bug_tracker.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 |
| SpdyFrameBuilder(size_t size, SpdyMajorVersion version); |
| |
| ~SpdyFrameBuilder(); |
| |
| // Returns the total size of the SpdyFrameBuilder's data, which may include |
| // multiple frames. |
| size_t length() const { return offset_ + 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_t 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, |
| uint8_t 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 BeginNewFrame(const SpdyFramer& framer, |
| SpdyFrameType type, |
| uint8_t flags, |
| SpdyStreamId stream_id); |
| |
| // Takes the buffer from the SpdyFrameBuilder. |
| SpdySerializedFrame take() { |
| if (version_ == HTTP2) { |
| SPDY_BUG_IF(SpdyConstants::GetMaxFrameSizeLimit(version_) < length_) |
| << "Frame length " << length_ |
| << " is longer than the maximum possible allowed length."; |
| } |
| SpdySerializedFrame rv(buffer_.release(), length(), true); |
| capacity_ = 0; |
| length_ = 0; |
| offset_ = 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_t value) { return WriteBytes(&value, sizeof(value)); } |
| bool WriteUInt16(uint16_t value) { |
| value = base::HostToNet16(value); |
| return WriteBytes(&value, sizeof(value)); |
| } |
| bool WriteUInt24(uint32_t value) { |
| value = base::HostToNet32(value); |
| return WriteBytes(reinterpret_cast<char*>(&value) + 1, |
| sizeof(value) - 1); |
| } |
| bool WriteUInt32(uint32_t value) { |
| value = base::HostToNet32(value); |
| return WriteBytes(&value, sizeof(value)); |
| } |
| bool WriteUInt64(uint64_t value) { |
| uint32_t upper = base::HostToNet32(static_cast<uint32_t>(value >> 32)); |
| uint32_t lower = base::HostToNet32(static_cast<uint32_t>(value)); |
| return (WriteBytes(&upper, sizeof(upper)) && |
| WriteBytes(&lower, sizeof(lower))); |
| } |
| bool WriteStringPiece16(const base::StringPiece& value); |
| bool WriteStringPiece32(const base::StringPiece& value); |
| bool WriteBytes(const void* data, uint32_t 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); |
| |
| // Update (in-place) the flags field in the frame being built to reflect the |
| // given flags value. |
| // Used only for SPDY versions >=4. |
| bool OverwriteFlags(const SpdyFramer& framer, uint8_t flags); |
| |
| 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; |
| |
| std::unique_ptr<char[]> buffer_; |
| size_t capacity_; // Allocation size of payload, set by constructor. |
| size_t length_; // Length of the latest frame in the buffer. |
| size_t offset_; // Position at which the latest frame begins. |
| |
| const SpdyMajorVersion version_; |
| }; |
| |
| } // namespace net |
| |
| #endif // NET_SPDY_SPDY_FRAME_BUILDER_H_ |