428 lines
11 KiB
Go
428 lines
11 KiB
Go
// Go support for Protocol Buffers - Google's data interchange format
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//
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// Copyright 2010 The Go Authors. All rights reserved.
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// https://github.com/golang/protobuf
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package proto
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/*
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* Routines for decoding protocol buffer data to construct in-memory representations.
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*/
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import (
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"errors"
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"fmt"
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"io"
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)
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// errOverflow is returned when an integer is too large to be represented.
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var errOverflow = errors.New("proto: integer overflow")
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// ErrInternalBadWireType is returned by generated code when an incorrect
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// wire type is encountered. It does not get returned to user code.
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var ErrInternalBadWireType = errors.New("proto: internal error: bad wiretype for oneof")
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// DecodeVarint reads a varint-encoded integer from the slice.
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// It returns the integer and the number of bytes consumed, or
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// zero if there is not enough.
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// This is the format for the
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// int32, int64, uint32, uint64, bool, and enum
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// protocol buffer types.
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func DecodeVarint(buf []byte) (x uint64, n int) {
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for shift := uint(0); shift < 64; shift += 7 {
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if n >= len(buf) {
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return 0, 0
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}
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b := uint64(buf[n])
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n++
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x |= (b & 0x7F) << shift
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if (b & 0x80) == 0 {
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return x, n
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}
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}
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// The number is too large to represent in a 64-bit value.
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return 0, 0
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}
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func (p *Buffer) decodeVarintSlow() (x uint64, err error) {
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i := p.index
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l := len(p.buf)
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for shift := uint(0); shift < 64; shift += 7 {
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if i >= l {
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err = io.ErrUnexpectedEOF
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return
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}
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b := p.buf[i]
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i++
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x |= (uint64(b) & 0x7F) << shift
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if b < 0x80 {
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p.index = i
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return
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}
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}
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// The number is too large to represent in a 64-bit value.
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err = errOverflow
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return
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}
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// DecodeVarint reads a varint-encoded integer from the Buffer.
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// This is the format for the
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// int32, int64, uint32, uint64, bool, and enum
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// protocol buffer types.
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func (p *Buffer) DecodeVarint() (x uint64, err error) {
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i := p.index
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buf := p.buf
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if i >= len(buf) {
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return 0, io.ErrUnexpectedEOF
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} else if buf[i] < 0x80 {
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p.index++
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return uint64(buf[i]), nil
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} else if len(buf)-i < 10 {
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return p.decodeVarintSlow()
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}
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var b uint64
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// we already checked the first byte
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x = uint64(buf[i]) - 0x80
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i++
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b = uint64(buf[i])
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i++
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x += b << 7
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if b&0x80 == 0 {
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goto done
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}
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x -= 0x80 << 7
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b = uint64(buf[i])
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i++
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x += b << 14
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if b&0x80 == 0 {
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goto done
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}
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x -= 0x80 << 14
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b = uint64(buf[i])
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i++
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x += b << 21
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if b&0x80 == 0 {
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goto done
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}
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x -= 0x80 << 21
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b = uint64(buf[i])
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i++
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x += b << 28
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if b&0x80 == 0 {
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goto done
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}
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x -= 0x80 << 28
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b = uint64(buf[i])
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i++
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x += b << 35
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if b&0x80 == 0 {
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goto done
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}
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x -= 0x80 << 35
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b = uint64(buf[i])
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i++
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x += b << 42
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if b&0x80 == 0 {
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goto done
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}
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x -= 0x80 << 42
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b = uint64(buf[i])
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i++
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x += b << 49
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if b&0x80 == 0 {
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goto done
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}
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x -= 0x80 << 49
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b = uint64(buf[i])
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i++
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x += b << 56
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if b&0x80 == 0 {
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goto done
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}
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x -= 0x80 << 56
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b = uint64(buf[i])
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i++
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x += b << 63
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if b&0x80 == 0 {
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goto done
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}
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return 0, errOverflow
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done:
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p.index = i
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return x, nil
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}
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// DecodeFixed64 reads a 64-bit integer from the Buffer.
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// This is the format for the
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// fixed64, sfixed64, and double protocol buffer types.
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func (p *Buffer) DecodeFixed64() (x uint64, err error) {
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// x, err already 0
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i := p.index + 8
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if i < 0 || i > len(p.buf) {
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err = io.ErrUnexpectedEOF
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return
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}
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p.index = i
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x = uint64(p.buf[i-8])
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x |= uint64(p.buf[i-7]) << 8
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x |= uint64(p.buf[i-6]) << 16
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x |= uint64(p.buf[i-5]) << 24
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x |= uint64(p.buf[i-4]) << 32
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x |= uint64(p.buf[i-3]) << 40
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x |= uint64(p.buf[i-2]) << 48
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x |= uint64(p.buf[i-1]) << 56
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return
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}
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// DecodeFixed32 reads a 32-bit integer from the Buffer.
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// This is the format for the
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// fixed32, sfixed32, and float protocol buffer types.
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func (p *Buffer) DecodeFixed32() (x uint64, err error) {
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// x, err already 0
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i := p.index + 4
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if i < 0 || i > len(p.buf) {
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err = io.ErrUnexpectedEOF
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return
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}
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p.index = i
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x = uint64(p.buf[i-4])
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x |= uint64(p.buf[i-3]) << 8
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x |= uint64(p.buf[i-2]) << 16
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x |= uint64(p.buf[i-1]) << 24
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return
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}
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// DecodeZigzag64 reads a zigzag-encoded 64-bit integer
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// from the Buffer.
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// This is the format used for the sint64 protocol buffer type.
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func (p *Buffer) DecodeZigzag64() (x uint64, err error) {
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x, err = p.DecodeVarint()
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if err != nil {
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return
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}
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x = (x >> 1) ^ uint64((int64(x&1)<<63)>>63)
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return
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}
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// DecodeZigzag32 reads a zigzag-encoded 32-bit integer
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// from the Buffer.
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// This is the format used for the sint32 protocol buffer type.
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func (p *Buffer) DecodeZigzag32() (x uint64, err error) {
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x, err = p.DecodeVarint()
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if err != nil {
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return
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}
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x = uint64((uint32(x) >> 1) ^ uint32((int32(x&1)<<31)>>31))
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return
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}
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// DecodeRawBytes reads a count-delimited byte buffer from the Buffer.
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// This is the format used for the bytes protocol buffer
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// type and for embedded messages.
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func (p *Buffer) DecodeRawBytes(alloc bool) (buf []byte, err error) {
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n, err := p.DecodeVarint()
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if err != nil {
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return nil, err
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}
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nb := int(n)
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if nb < 0 {
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return nil, fmt.Errorf("proto: bad byte length %d", nb)
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}
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end := p.index + nb
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if end < p.index || end > len(p.buf) {
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return nil, io.ErrUnexpectedEOF
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}
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if !alloc {
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// todo: check if can get more uses of alloc=false
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buf = p.buf[p.index:end]
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p.index += nb
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return
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}
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buf = make([]byte, nb)
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copy(buf, p.buf[p.index:])
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p.index += nb
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return
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}
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// DecodeStringBytes reads an encoded string from the Buffer.
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// This is the format used for the proto2 string type.
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func (p *Buffer) DecodeStringBytes() (s string, err error) {
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buf, err := p.DecodeRawBytes(false)
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if err != nil {
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return
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}
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return string(buf), nil
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}
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// Unmarshaler is the interface representing objects that can
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// unmarshal themselves. The argument points to data that may be
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// overwritten, so implementations should not keep references to the
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// buffer.
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// Unmarshal implementations should not clear the receiver.
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// Any unmarshaled data should be merged into the receiver.
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// Callers of Unmarshal that do not want to retain existing data
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// should Reset the receiver before calling Unmarshal.
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type Unmarshaler interface {
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Unmarshal([]byte) error
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}
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// newUnmarshaler is the interface representing objects that can
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// unmarshal themselves. The semantics are identical to Unmarshaler.
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//
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// This exists to support protoc-gen-go generated messages.
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// The proto package will stop type-asserting to this interface in the future.
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//
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// DO NOT DEPEND ON THIS.
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type newUnmarshaler interface {
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XXX_Unmarshal([]byte) error
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}
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// Unmarshal parses the protocol buffer representation in buf and places the
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// decoded result in pb. If the struct underlying pb does not match
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// the data in buf, the results can be unpredictable.
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//
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// Unmarshal resets pb before starting to unmarshal, so any
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// existing data in pb is always removed. Use UnmarshalMerge
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// to preserve and append to existing data.
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func Unmarshal(buf []byte, pb Message) error {
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pb.Reset()
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if u, ok := pb.(newUnmarshaler); ok {
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return u.XXX_Unmarshal(buf)
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}
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if u, ok := pb.(Unmarshaler); ok {
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return u.Unmarshal(buf)
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}
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return NewBuffer(buf).Unmarshal(pb)
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}
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// UnmarshalMerge parses the protocol buffer representation in buf and
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// writes the decoded result to pb. If the struct underlying pb does not match
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// the data in buf, the results can be unpredictable.
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//
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// UnmarshalMerge merges into existing data in pb.
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// Most code should use Unmarshal instead.
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func UnmarshalMerge(buf []byte, pb Message) error {
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if u, ok := pb.(newUnmarshaler); ok {
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return u.XXX_Unmarshal(buf)
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}
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if u, ok := pb.(Unmarshaler); ok {
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// NOTE: The history of proto have unfortunately been inconsistent
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// whether Unmarshaler should or should not implicitly clear itself.
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// Some implementations do, most do not.
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// Thus, calling this here may or may not do what people want.
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//
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// See https://github.com/golang/protobuf/issues/424
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return u.Unmarshal(buf)
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}
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return NewBuffer(buf).Unmarshal(pb)
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}
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// DecodeMessage reads a count-delimited message from the Buffer.
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func (p *Buffer) DecodeMessage(pb Message) error {
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enc, err := p.DecodeRawBytes(false)
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if err != nil {
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return err
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}
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return NewBuffer(enc).Unmarshal(pb)
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}
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// DecodeGroup reads a tag-delimited group from the Buffer.
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// StartGroup tag is already consumed. This function consumes
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// EndGroup tag.
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func (p *Buffer) DecodeGroup(pb Message) error {
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b := p.buf[p.index:]
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x, y := findEndGroup(b)
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if x < 0 {
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return io.ErrUnexpectedEOF
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}
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err := Unmarshal(b[:x], pb)
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p.index += y
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return err
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}
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// Unmarshal parses the protocol buffer representation in the
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// Buffer and places the decoded result in pb. If the struct
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// underlying pb does not match the data in the buffer, the results can be
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// unpredictable.
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//
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// Unlike proto.Unmarshal, this does not reset pb before starting to unmarshal.
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func (p *Buffer) Unmarshal(pb Message) error {
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// If the object can unmarshal itself, let it.
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if u, ok := pb.(newUnmarshaler); ok {
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err := u.XXX_Unmarshal(p.buf[p.index:])
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p.index = len(p.buf)
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return err
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}
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if u, ok := pb.(Unmarshaler); ok {
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// NOTE: The history of proto have unfortunately been inconsistent
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// whether Unmarshaler should or should not implicitly clear itself.
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// Some implementations do, most do not.
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// Thus, calling this here may or may not do what people want.
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//
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// See https://github.com/golang/protobuf/issues/424
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err := u.Unmarshal(p.buf[p.index:])
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p.index = len(p.buf)
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return err
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}
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// Slow workaround for messages that aren't Unmarshalers.
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// This includes some hand-coded .pb.go files and
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// bootstrap protos.
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// TODO: fix all of those and then add Unmarshal to
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// the Message interface. Then:
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// The cast above and code below can be deleted.
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// The old unmarshaler can be deleted.
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// Clients can call Unmarshal directly (can already do that, actually).
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var info InternalMessageInfo
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err := info.Unmarshal(pb, p.buf[p.index:])
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p.index = len(p.buf)
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return err
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}
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