diff options
Diffstat (limited to 'vendor/go.opencensus.io/tag/map_codec.go')
-rw-r--r-- | vendor/go.opencensus.io/tag/map_codec.go | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/vendor/go.opencensus.io/tag/map_codec.go b/vendor/go.opencensus.io/tag/map_codec.go new file mode 100644 index 0000000..33be1f0 --- /dev/null +++ b/vendor/go.opencensus.io/tag/map_codec.go @@ -0,0 +1,221 @@ +// Copyright 2017, OpenCensus Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// + +package tag + +import ( + "encoding/binary" + "fmt" +) + +// KeyType defines the types of keys allowed. Currently only keyTypeString is +// supported. +type keyType byte + +const ( + keyTypeString keyType = iota + keyTypeInt64 + keyTypeTrue + keyTypeFalse + + tagsVersionID = byte(0) +) + +type encoderGRPC struct { + buf []byte + writeIdx, readIdx int +} + +// writeKeyString writes the fieldID '0' followed by the key string and value +// string. +func (eg *encoderGRPC) writeTagString(k, v string) { + eg.writeByte(byte(keyTypeString)) + eg.writeStringWithVarintLen(k) + eg.writeStringWithVarintLen(v) +} + +func (eg *encoderGRPC) writeTagUint64(k string, i uint64) { + eg.writeByte(byte(keyTypeInt64)) + eg.writeStringWithVarintLen(k) + eg.writeUint64(i) +} + +func (eg *encoderGRPC) writeTagTrue(k string) { + eg.writeByte(byte(keyTypeTrue)) + eg.writeStringWithVarintLen(k) +} + +func (eg *encoderGRPC) writeTagFalse(k string) { + eg.writeByte(byte(keyTypeFalse)) + eg.writeStringWithVarintLen(k) +} + +func (eg *encoderGRPC) writeBytesWithVarintLen(bytes []byte) { + length := len(bytes) + + eg.growIfRequired(binary.MaxVarintLen64 + length) + eg.writeIdx += binary.PutUvarint(eg.buf[eg.writeIdx:], uint64(length)) + copy(eg.buf[eg.writeIdx:], bytes) + eg.writeIdx += length +} + +func (eg *encoderGRPC) writeStringWithVarintLen(s string) { + length := len(s) + + eg.growIfRequired(binary.MaxVarintLen64 + length) + eg.writeIdx += binary.PutUvarint(eg.buf[eg.writeIdx:], uint64(length)) + copy(eg.buf[eg.writeIdx:], s) + eg.writeIdx += length +} + +func (eg *encoderGRPC) writeByte(v byte) { + eg.growIfRequired(1) + eg.buf[eg.writeIdx] = v + eg.writeIdx++ +} + +func (eg *encoderGRPC) writeUint32(i uint32) { + eg.growIfRequired(4) + binary.LittleEndian.PutUint32(eg.buf[eg.writeIdx:], i) + eg.writeIdx += 4 +} + +func (eg *encoderGRPC) writeUint64(i uint64) { + eg.growIfRequired(8) + binary.LittleEndian.PutUint64(eg.buf[eg.writeIdx:], i) + eg.writeIdx += 8 +} + +func (eg *encoderGRPC) readByte() byte { + b := eg.buf[eg.readIdx] + eg.readIdx++ + return b +} + +func (eg *encoderGRPC) readUint32() uint32 { + i := binary.LittleEndian.Uint32(eg.buf[eg.readIdx:]) + eg.readIdx += 4 + return i +} + +func (eg *encoderGRPC) readUint64() uint64 { + i := binary.LittleEndian.Uint64(eg.buf[eg.readIdx:]) + eg.readIdx += 8 + return i +} + +func (eg *encoderGRPC) readBytesWithVarintLen() ([]byte, error) { + if eg.readEnded() { + return nil, fmt.Errorf("unexpected end while readBytesWithVarintLen '%x' starting at idx '%v'", eg.buf, eg.readIdx) + } + length, valueStart := binary.Uvarint(eg.buf[eg.readIdx:]) + if valueStart <= 0 { + return nil, fmt.Errorf("unexpected end while readBytesWithVarintLen '%x' starting at idx '%v'", eg.buf, eg.readIdx) + } + + valueStart += eg.readIdx + valueEnd := valueStart + int(length) + if valueEnd > len(eg.buf) { + return nil, fmt.Errorf("malformed encoding: length:%v, upper:%v, maxLength:%v", length, valueEnd, len(eg.buf)) + } + + eg.readIdx = valueEnd + return eg.buf[valueStart:valueEnd], nil +} + +func (eg *encoderGRPC) readStringWithVarintLen() (string, error) { + bytes, err := eg.readBytesWithVarintLen() + if err != nil { + return "", err + } + return string(bytes), nil +} + +func (eg *encoderGRPC) growIfRequired(expected int) { + if len(eg.buf)-eg.writeIdx < expected { + tmp := make([]byte, 2*(len(eg.buf)+1)+expected) + copy(tmp, eg.buf) + eg.buf = tmp + } +} + +func (eg *encoderGRPC) readEnded() bool { + return eg.readIdx >= len(eg.buf) +} + +func (eg *encoderGRPC) bytes() []byte { + return eg.buf[:eg.writeIdx] +} + +// Encode encodes the tag map into a []byte. It is useful to propagate +// the tag maps on wire in binary format. +func Encode(m *Map) []byte { + eg := &encoderGRPC{ + buf: make([]byte, len(m.m)), + } + eg.writeByte(byte(tagsVersionID)) + for k, v := range m.m { + eg.writeByte(byte(keyTypeString)) + eg.writeStringWithVarintLen(k.name) + eg.writeBytesWithVarintLen([]byte(v)) + } + return eg.bytes() +} + +// Decode decodes the given []byte into a tag map. +func Decode(bytes []byte) (*Map, error) { + ts := newMap() + + eg := &encoderGRPC{ + buf: bytes, + } + if len(eg.buf) == 0 { + return ts, nil + } + + version := eg.readByte() + if version > tagsVersionID { + return nil, fmt.Errorf("cannot decode: unsupported version: %q; supports only up to: %q", version, tagsVersionID) + } + + for !eg.readEnded() { + typ := keyType(eg.readByte()) + + if typ != keyTypeString { + return nil, fmt.Errorf("cannot decode: invalid key type: %q", typ) + } + + k, err := eg.readBytesWithVarintLen() + if err != nil { + return nil, err + } + + v, err := eg.readBytesWithVarintLen() + if err != nil { + return nil, err + } + + key, err := NewKey(string(k)) + if err != nil { + return nil, err // no partial failures + } + val := string(v) + if !checkValue(val) { + return nil, errInvalidValue // no partial failures + } + ts.upsert(key, val) + } + return ts, nil +} |