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-rw-r--r--src/dma/vendor/github.com/streadway/amqp/read.go456
1 files changed, 456 insertions, 0 deletions
diff --git a/src/dma/vendor/github.com/streadway/amqp/read.go b/src/dma/vendor/github.com/streadway/amqp/read.go
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+// Copyright (c) 2012, Sean Treadway, SoundCloud Ltd.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+// Source code and contact info at http://github.com/streadway/amqp
+
+package amqp
+
+import (
+ "bytes"
+ "encoding/binary"
+ "errors"
+ "io"
+ "time"
+)
+
+/*
+Reads a frame from an input stream and returns an interface that can be cast into
+one of the following:
+
+ methodFrame
+ PropertiesFrame
+ bodyFrame
+ heartbeatFrame
+
+2.3.5 frame Details
+
+All frames consist of a header (7 octets), a payload of arbitrary size, and a
+'frame-end' octet that detects malformed frames:
+
+ 0 1 3 7 size+7 size+8
+ +------+---------+-------------+ +------------+ +-----------+
+ | type | channel | size | | payload | | frame-end |
+ +------+---------+-------------+ +------------+ +-----------+
+ octet short long size octets octet
+
+To read a frame, we:
+ 1. Read the header and check the frame type and channel.
+ 2. Depending on the frame type, we read the payload and process it.
+ 3. Read the frame end octet.
+
+In realistic implementations where performance is a concern, we would use
+“read-ahead buffering” or
+
+“gathering reads” to avoid doing three separate system calls to read a frame.
+*/
+func (r *reader) ReadFrame() (frame frame, err error) {
+ var scratch [7]byte
+
+ if _, err = io.ReadFull(r.r, scratch[:7]); err != nil {
+ return
+ }
+
+ typ := uint8(scratch[0])
+ channel := binary.BigEndian.Uint16(scratch[1:3])
+ size := binary.BigEndian.Uint32(scratch[3:7])
+
+ switch typ {
+ case frameMethod:
+ if frame, err = r.parseMethodFrame(channel, size); err != nil {
+ return
+ }
+
+ case frameHeader:
+ if frame, err = r.parseHeaderFrame(channel, size); err != nil {
+ return
+ }
+
+ case frameBody:
+ if frame, err = r.parseBodyFrame(channel, size); err != nil {
+ return nil, err
+ }
+
+ case frameHeartbeat:
+ if frame, err = r.parseHeartbeatFrame(channel, size); err != nil {
+ return
+ }
+
+ default:
+ return nil, ErrFrame
+ }
+
+ if _, err = io.ReadFull(r.r, scratch[:1]); err != nil {
+ return nil, err
+ }
+
+ if scratch[0] != frameEnd {
+ return nil, ErrFrame
+ }
+
+ return
+}
+
+func readShortstr(r io.Reader) (v string, err error) {
+ var length uint8
+ if err = binary.Read(r, binary.BigEndian, &length); err != nil {
+ return
+ }
+
+ bytes := make([]byte, length)
+ if _, err = io.ReadFull(r, bytes); err != nil {
+ return
+ }
+ return string(bytes), nil
+}
+
+func readLongstr(r io.Reader) (v string, err error) {
+ var length uint32
+ if err = binary.Read(r, binary.BigEndian, &length); err != nil {
+ return
+ }
+
+ // slices can't be longer than max int32 value
+ if length > (^uint32(0) >> 1) {
+ return
+ }
+
+ bytes := make([]byte, length)
+ if _, err = io.ReadFull(r, bytes); err != nil {
+ return
+ }
+ return string(bytes), nil
+}
+
+func readDecimal(r io.Reader) (v Decimal, err error) {
+ if err = binary.Read(r, binary.BigEndian, &v.Scale); err != nil {
+ return
+ }
+ if err = binary.Read(r, binary.BigEndian, &v.Value); err != nil {
+ return
+ }
+ return
+}
+
+func readFloat32(r io.Reader) (v float32, err error) {
+ if err = binary.Read(r, binary.BigEndian, &v); err != nil {
+ return
+ }
+ return
+}
+
+func readFloat64(r io.Reader) (v float64, err error) {
+ if err = binary.Read(r, binary.BigEndian, &v); err != nil {
+ return
+ }
+ return
+}
+
+func readTimestamp(r io.Reader) (v time.Time, err error) {
+ var sec int64
+ if err = binary.Read(r, binary.BigEndian, &sec); err != nil {
+ return
+ }
+ return time.Unix(sec, 0), nil
+}
+
+/*
+'A': []interface{}
+'D': Decimal
+'F': Table
+'I': int32
+'S': string
+'T': time.Time
+'V': nil
+'b': byte
+'d': float64
+'f': float32
+'l': int64
+'s': int16
+'t': bool
+'x': []byte
+*/
+func readField(r io.Reader) (v interface{}, err error) {
+ var typ byte
+ if err = binary.Read(r, binary.BigEndian, &typ); err != nil {
+ return
+ }
+
+ switch typ {
+ case 't':
+ var value uint8
+ if err = binary.Read(r, binary.BigEndian, &value); err != nil {
+ return
+ }
+ return (value != 0), nil
+
+ case 'b':
+ var value [1]byte
+ if _, err = io.ReadFull(r, value[0:1]); err != nil {
+ return
+ }
+ return value[0], nil
+
+ case 's':
+ var value int16
+ if err = binary.Read(r, binary.BigEndian, &value); err != nil {
+ return
+ }
+ return value, nil
+
+ case 'I':
+ var value int32
+ if err = binary.Read(r, binary.BigEndian, &value); err != nil {
+ return
+ }
+ return value, nil
+
+ case 'l':
+ var value int64
+ if err = binary.Read(r, binary.BigEndian, &value); err != nil {
+ return
+ }
+ return value, nil
+
+ case 'f':
+ var value float32
+ if err = binary.Read(r, binary.BigEndian, &value); err != nil {
+ return
+ }
+ return value, nil
+
+ case 'd':
+ var value float64
+ if err = binary.Read(r, binary.BigEndian, &value); err != nil {
+ return
+ }
+ return value, nil
+
+ case 'D':
+ return readDecimal(r)
+
+ case 'S':
+ return readLongstr(r)
+
+ case 'A':
+ return readArray(r)
+
+ case 'T':
+ return readTimestamp(r)
+
+ case 'F':
+ return readTable(r)
+
+ case 'x':
+ var len int32
+ if err = binary.Read(r, binary.BigEndian, &len); err != nil {
+ return nil, err
+ }
+
+ value := make([]byte, len)
+ if _, err = io.ReadFull(r, value); err != nil {
+ return nil, err
+ }
+ return value, err
+
+ case 'V':
+ return nil, nil
+ }
+
+ return nil, ErrSyntax
+}
+
+/*
+ Field tables are long strings that contain packed name-value pairs. The
+ name-value pairs are encoded as short string defining the name, and octet
+ defining the values type and then the value itself. The valid field types for
+ tables are an extension of the native integer, bit, string, and timestamp
+ types, and are shown in the grammar. Multi-octet integer fields are always
+ held in network byte order.
+*/
+func readTable(r io.Reader) (table Table, err error) {
+ var nested bytes.Buffer
+ var str string
+
+ if str, err = readLongstr(r); err != nil {
+ return
+ }
+
+ nested.Write([]byte(str))
+
+ table = make(Table)
+
+ for nested.Len() > 0 {
+ var key string
+ var value interface{}
+
+ if key, err = readShortstr(&nested); err != nil {
+ return
+ }
+
+ if value, err = readField(&nested); err != nil {
+ return
+ }
+
+ table[key] = value
+ }
+
+ return
+}
+
+func readArray(r io.Reader) ([]interface{}, error) {
+ var (
+ size uint32
+ err error
+ )
+
+ if err = binary.Read(r, binary.BigEndian, &size); err != nil {
+ return nil, err
+ }
+
+ var (
+ lim = &io.LimitedReader{R: r, N: int64(size)}
+ arr = []interface{}{}
+ field interface{}
+ )
+
+ for {
+ if field, err = readField(lim); err != nil {
+ if err == io.EOF {
+ break
+ }
+ return nil, err
+ }
+ arr = append(arr, field)
+ }
+
+ return arr, nil
+}
+
+// Checks if this bit mask matches the flags bitset
+func hasProperty(mask uint16, prop int) bool {
+ return int(mask)&prop > 0
+}
+
+func (r *reader) parseHeaderFrame(channel uint16, size uint32) (frame frame, err error) {
+ hf := &headerFrame{
+ ChannelId: channel,
+ }
+
+ if err = binary.Read(r.r, binary.BigEndian, &hf.ClassId); err != nil {
+ return
+ }
+
+ if err = binary.Read(r.r, binary.BigEndian, &hf.weight); err != nil {
+ return
+ }
+
+ if err = binary.Read(r.r, binary.BigEndian, &hf.Size); err != nil {
+ return
+ }
+
+ var flags uint16
+
+ if err = binary.Read(r.r, binary.BigEndian, &flags); err != nil {
+ return
+ }
+
+ if hasProperty(flags, flagContentType) {
+ if hf.Properties.ContentType, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagContentEncoding) {
+ if hf.Properties.ContentEncoding, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagHeaders) {
+ if hf.Properties.Headers, err = readTable(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagDeliveryMode) {
+ if err = binary.Read(r.r, binary.BigEndian, &hf.Properties.DeliveryMode); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagPriority) {
+ if err = binary.Read(r.r, binary.BigEndian, &hf.Properties.Priority); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagCorrelationId) {
+ if hf.Properties.CorrelationId, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagReplyTo) {
+ if hf.Properties.ReplyTo, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagExpiration) {
+ if hf.Properties.Expiration, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagMessageId) {
+ if hf.Properties.MessageId, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagTimestamp) {
+ if hf.Properties.Timestamp, err = readTimestamp(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagType) {
+ if hf.Properties.Type, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagUserId) {
+ if hf.Properties.UserId, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagAppId) {
+ if hf.Properties.AppId, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+ if hasProperty(flags, flagReserved1) {
+ if hf.Properties.reserved1, err = readShortstr(r.r); err != nil {
+ return
+ }
+ }
+
+ return hf, nil
+}
+
+func (r *reader) parseBodyFrame(channel uint16, size uint32) (frame frame, err error) {
+ bf := &bodyFrame{
+ ChannelId: channel,
+ Body: make([]byte, size),
+ }
+
+ if _, err = io.ReadFull(r.r, bf.Body); err != nil {
+ return nil, err
+ }
+
+ return bf, nil
+}
+
+var errHeartbeatPayload = errors.New("Heartbeats should not have a payload")
+
+func (r *reader) parseHeartbeatFrame(channel uint16, size uint32) (frame frame, err error) {
+ hf := &heartbeatFrame{
+ ChannelId: channel,
+ }
+
+ if size > 0 {
+ return nil, errHeartbeatPayload
+ }
+
+ return hf, nil
+}