mirror of https://github.com/docker/cli.git
954 lines
23 KiB
Go
954 lines
23 KiB
Go
// Copyright 2019+ Klaus Post. All rights reserved.
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// License information can be found in the LICENSE file.
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// Based on work by Yann Collet, released under BSD License.
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package zstd
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import (
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"context"
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"encoding/binary"
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"io"
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"sync"
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"github.com/klauspost/compress/zstd/internal/xxhash"
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)
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// Decoder provides decoding of zstandard streams.
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// The decoder has been designed to operate without allocations after a warmup.
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// This means that you should store the decoder for best performance.
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// To re-use a stream decoder, use the Reset(r io.Reader) error to switch to another stream.
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// A decoder can safely be re-used even if the previous stream failed.
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// To release the resources, you must call the Close() function on a decoder.
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type Decoder struct {
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o decoderOptions
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// Unreferenced decoders, ready for use.
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decoders chan *blockDec
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// Current read position used for Reader functionality.
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current decoderState
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// sync stream decoding
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syncStream struct {
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decodedFrame uint64
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br readerWrapper
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enabled bool
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inFrame bool
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dstBuf []byte
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}
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frame *frameDec
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// Custom dictionaries.
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dicts map[uint32]*dict
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// streamWg is the waitgroup for all streams
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streamWg sync.WaitGroup
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}
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// decoderState is used for maintaining state when the decoder
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// is used for streaming.
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type decoderState struct {
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// current block being written to stream.
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decodeOutput
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// output in order to be written to stream.
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output chan decodeOutput
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// cancel remaining output.
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cancel context.CancelFunc
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// crc of current frame
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crc *xxhash.Digest
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flushed bool
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}
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var (
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// Check the interfaces we want to support.
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_ = io.WriterTo(&Decoder{})
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_ = io.Reader(&Decoder{})
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)
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// NewReader creates a new decoder.
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// A nil Reader can be provided in which case Reset can be used to start a decode.
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//
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// A Decoder can be used in two modes:
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//
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// 1) As a stream, or
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// 2) For stateless decoding using DecodeAll.
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//
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// Only a single stream can be decoded concurrently, but the same decoder
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// can run multiple concurrent stateless decodes. It is even possible to
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// use stateless decodes while a stream is being decoded.
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//
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// The Reset function can be used to initiate a new stream, which is will considerably
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// reduce the allocations normally caused by NewReader.
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func NewReader(r io.Reader, opts ...DOption) (*Decoder, error) {
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initPredefined()
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var d Decoder
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d.o.setDefault()
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for _, o := range opts {
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err := o(&d.o)
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if err != nil {
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return nil, err
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}
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}
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d.current.crc = xxhash.New()
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d.current.flushed = true
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if r == nil {
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d.current.err = ErrDecoderNilInput
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}
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// Transfer option dicts.
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d.dicts = make(map[uint32]*dict, len(d.o.dicts))
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for _, dc := range d.o.dicts {
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d.dicts[dc.id] = dc
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}
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d.o.dicts = nil
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// Create decoders
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d.decoders = make(chan *blockDec, d.o.concurrent)
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for i := 0; i < d.o.concurrent; i++ {
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dec := newBlockDec(d.o.lowMem)
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dec.localFrame = newFrameDec(d.o)
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d.decoders <- dec
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}
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if r == nil {
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return &d, nil
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}
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return &d, d.Reset(r)
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}
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// Read bytes from the decompressed stream into p.
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// Returns the number of bytes written and any error that occurred.
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// When the stream is done, io.EOF will be returned.
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func (d *Decoder) Read(p []byte) (int, error) {
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var n int
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for {
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if len(d.current.b) > 0 {
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filled := copy(p, d.current.b)
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p = p[filled:]
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d.current.b = d.current.b[filled:]
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n += filled
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}
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if len(p) == 0 {
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break
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}
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if len(d.current.b) == 0 {
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// We have an error and no more data
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if d.current.err != nil {
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break
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}
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if !d.nextBlock(n == 0) {
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return n, d.current.err
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}
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}
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}
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if len(d.current.b) > 0 {
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if debugDecoder {
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println("returning", n, "still bytes left:", len(d.current.b))
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}
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// Only return error at end of block
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return n, nil
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}
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if d.current.err != nil {
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d.drainOutput()
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}
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if debugDecoder {
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println("returning", n, d.current.err, len(d.decoders))
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}
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return n, d.current.err
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}
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// Reset will reset the decoder the supplied stream after the current has finished processing.
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// Note that this functionality cannot be used after Close has been called.
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// Reset can be called with a nil reader to release references to the previous reader.
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// After being called with a nil reader, no other operations than Reset or DecodeAll or Close
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// should be used.
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func (d *Decoder) Reset(r io.Reader) error {
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if d.current.err == ErrDecoderClosed {
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return d.current.err
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}
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d.drainOutput()
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d.syncStream.br.r = nil
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if r == nil {
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d.current.err = ErrDecoderNilInput
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if len(d.current.b) > 0 {
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d.current.b = d.current.b[:0]
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}
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d.current.flushed = true
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return nil
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}
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// If bytes buffer and < 5MB, do sync decoding anyway.
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if bb, ok := r.(byter); ok && bb.Len() < d.o.decodeBufsBelow && !d.o.limitToCap {
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bb2 := bb
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if debugDecoder {
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println("*bytes.Buffer detected, doing sync decode, len:", bb.Len())
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}
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b := bb2.Bytes()
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var dst []byte
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if cap(d.syncStream.dstBuf) > 0 {
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dst = d.syncStream.dstBuf[:0]
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}
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dst, err := d.DecodeAll(b, dst)
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if err == nil {
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err = io.EOF
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}
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// Save output buffer
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d.syncStream.dstBuf = dst
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d.current.b = dst
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d.current.err = err
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d.current.flushed = true
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if debugDecoder {
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println("sync decode to", len(dst), "bytes, err:", err)
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}
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return nil
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}
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// Remove current block.
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d.stashDecoder()
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d.current.decodeOutput = decodeOutput{}
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d.current.err = nil
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d.current.flushed = false
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d.current.d = nil
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d.syncStream.dstBuf = nil
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// Ensure no-one else is still running...
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d.streamWg.Wait()
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if d.frame == nil {
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d.frame = newFrameDec(d.o)
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}
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if d.o.concurrent == 1 {
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return d.startSyncDecoder(r)
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}
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d.current.output = make(chan decodeOutput, d.o.concurrent)
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ctx, cancel := context.WithCancel(context.Background())
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d.current.cancel = cancel
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d.streamWg.Add(1)
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go d.startStreamDecoder(ctx, r, d.current.output)
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return nil
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}
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// drainOutput will drain the output until errEndOfStream is sent.
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func (d *Decoder) drainOutput() {
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if d.current.cancel != nil {
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if debugDecoder {
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println("cancelling current")
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}
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d.current.cancel()
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d.current.cancel = nil
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}
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if d.current.d != nil {
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if debugDecoder {
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printf("re-adding current decoder %p, decoders: %d", d.current.d, len(d.decoders))
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}
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d.decoders <- d.current.d
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d.current.d = nil
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d.current.b = nil
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}
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if d.current.output == nil || d.current.flushed {
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println("current already flushed")
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return
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}
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for v := range d.current.output {
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if v.d != nil {
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if debugDecoder {
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printf("re-adding decoder %p", v.d)
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}
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d.decoders <- v.d
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}
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}
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d.current.output = nil
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d.current.flushed = true
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}
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// WriteTo writes data to w until there's no more data to write or when an error occurs.
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// The return value n is the number of bytes written.
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// Any error encountered during the write is also returned.
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func (d *Decoder) WriteTo(w io.Writer) (int64, error) {
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var n int64
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for {
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if len(d.current.b) > 0 {
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n2, err2 := w.Write(d.current.b)
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n += int64(n2)
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if err2 != nil && (d.current.err == nil || d.current.err == io.EOF) {
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d.current.err = err2
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} else if n2 != len(d.current.b) {
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d.current.err = io.ErrShortWrite
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}
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}
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if d.current.err != nil {
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break
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}
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d.nextBlock(true)
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}
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err := d.current.err
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if err != nil {
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d.drainOutput()
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}
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if err == io.EOF {
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err = nil
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}
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return n, err
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}
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// DecodeAll allows stateless decoding of a blob of bytes.
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// Output will be appended to dst, so if the destination size is known
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// you can pre-allocate the destination slice to avoid allocations.
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// DecodeAll can be used concurrently.
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// The Decoder concurrency limits will be respected.
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func (d *Decoder) DecodeAll(input, dst []byte) ([]byte, error) {
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if d.decoders == nil {
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return dst, ErrDecoderClosed
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}
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// Grab a block decoder and frame decoder.
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block := <-d.decoders
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frame := block.localFrame
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initialSize := len(dst)
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defer func() {
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if debugDecoder {
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printf("re-adding decoder: %p", block)
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}
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frame.rawInput = nil
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frame.bBuf = nil
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if frame.history.decoders.br != nil {
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frame.history.decoders.br.in = nil
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}
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d.decoders <- block
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}()
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frame.bBuf = input
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for {
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frame.history.reset()
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err := frame.reset(&frame.bBuf)
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if err != nil {
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if err == io.EOF {
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if debugDecoder {
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println("frame reset return EOF")
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}
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return dst, nil
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}
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return dst, err
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}
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if err = d.setDict(frame); err != nil {
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return nil, err
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}
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if frame.WindowSize > d.o.maxWindowSize {
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if debugDecoder {
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println("window size exceeded:", frame.WindowSize, ">", d.o.maxWindowSize)
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}
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return dst, ErrWindowSizeExceeded
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}
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if frame.FrameContentSize != fcsUnknown {
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if frame.FrameContentSize > d.o.maxDecodedSize-uint64(len(dst)-initialSize) {
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if debugDecoder {
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println("decoder size exceeded; fcs:", frame.FrameContentSize, "> mcs:", d.o.maxDecodedSize-uint64(len(dst)-initialSize), "len:", len(dst))
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}
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return dst, ErrDecoderSizeExceeded
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}
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if d.o.limitToCap && frame.FrameContentSize > uint64(cap(dst)-len(dst)) {
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if debugDecoder {
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println("decoder size exceeded; fcs:", frame.FrameContentSize, "> (cap-len)", cap(dst)-len(dst))
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}
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return dst, ErrDecoderSizeExceeded
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}
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if cap(dst)-len(dst) < int(frame.FrameContentSize) {
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dst2 := make([]byte, len(dst), len(dst)+int(frame.FrameContentSize)+compressedBlockOverAlloc)
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copy(dst2, dst)
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dst = dst2
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}
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}
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if cap(dst) == 0 && !d.o.limitToCap {
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// Allocate len(input) * 2 by default if nothing is provided
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// and we didn't get frame content size.
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size := len(input) * 2
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// Cap to 1 MB.
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if size > 1<<20 {
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size = 1 << 20
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}
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if uint64(size) > d.o.maxDecodedSize {
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size = int(d.o.maxDecodedSize)
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}
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dst = make([]byte, 0, size)
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}
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dst, err = frame.runDecoder(dst, block)
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if err != nil {
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return dst, err
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}
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if uint64(len(dst)-initialSize) > d.o.maxDecodedSize {
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return dst, ErrDecoderSizeExceeded
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}
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if len(frame.bBuf) == 0 {
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if debugDecoder {
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println("frame dbuf empty")
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}
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break
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}
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}
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return dst, nil
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}
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// nextBlock returns the next block.
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// If an error occurs d.err will be set.
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// Optionally the function can block for new output.
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// If non-blocking mode is used the returned boolean will be false
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// if no data was available without blocking.
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func (d *Decoder) nextBlock(blocking bool) (ok bool) {
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if d.current.err != nil {
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// Keep error state.
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return false
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}
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d.current.b = d.current.b[:0]
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// SYNC:
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if d.syncStream.enabled {
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if !blocking {
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return false
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}
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ok = d.nextBlockSync()
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if !ok {
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d.stashDecoder()
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}
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return ok
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}
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//ASYNC:
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d.stashDecoder()
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if blocking {
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d.current.decodeOutput, ok = <-d.current.output
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} else {
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select {
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case d.current.decodeOutput, ok = <-d.current.output:
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default:
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return false
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}
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}
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if !ok {
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// This should not happen, so signal error state...
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d.current.err = io.ErrUnexpectedEOF
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return false
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}
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next := d.current.decodeOutput
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if next.d != nil && next.d.async.newHist != nil {
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d.current.crc.Reset()
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}
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if debugDecoder {
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var tmp [4]byte
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binary.LittleEndian.PutUint32(tmp[:], uint32(xxhash.Sum64(next.b)))
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println("got", len(d.current.b), "bytes, error:", d.current.err, "data crc:", tmp)
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}
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if d.o.ignoreChecksum {
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return true
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}
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if len(next.b) > 0 {
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n, err := d.current.crc.Write(next.b)
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if err == nil {
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if n != len(next.b) {
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d.current.err = io.ErrShortWrite
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}
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}
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}
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if next.err == nil && next.d != nil && next.d.hasCRC {
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got := uint32(d.current.crc.Sum64())
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if got != next.d.checkCRC {
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if debugDecoder {
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printf("CRC Check Failed: %08x (got) != %08x (on stream)\n", got, next.d.checkCRC)
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}
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d.current.err = ErrCRCMismatch
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} else {
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if debugDecoder {
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printf("CRC ok %08x\n", got)
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}
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}
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}
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return true
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}
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func (d *Decoder) nextBlockSync() (ok bool) {
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if d.current.d == nil {
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d.current.d = <-d.decoders
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}
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for len(d.current.b) == 0 {
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if !d.syncStream.inFrame {
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d.frame.history.reset()
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d.current.err = d.frame.reset(&d.syncStream.br)
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if d.current.err == nil {
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d.current.err = d.setDict(d.frame)
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}
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if d.current.err != nil {
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return false
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}
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if d.frame.WindowSize > d.o.maxDecodedSize || d.frame.WindowSize > d.o.maxWindowSize {
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d.current.err = ErrDecoderSizeExceeded
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return false
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}
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d.syncStream.decodedFrame = 0
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d.syncStream.inFrame = true
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}
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d.current.err = d.frame.next(d.current.d)
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if d.current.err != nil {
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return false
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}
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d.frame.history.ensureBlock()
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if debugDecoder {
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println("History trimmed:", len(d.frame.history.b), "decoded already:", d.syncStream.decodedFrame)
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}
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histBefore := len(d.frame.history.b)
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d.current.err = d.current.d.decodeBuf(&d.frame.history)
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if d.current.err != nil {
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println("error after:", d.current.err)
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return false
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}
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d.current.b = d.frame.history.b[histBefore:]
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if debugDecoder {
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println("history after:", len(d.frame.history.b))
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}
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// Check frame size (before CRC)
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d.syncStream.decodedFrame += uint64(len(d.current.b))
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if d.syncStream.decodedFrame > d.frame.FrameContentSize {
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if debugDecoder {
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printf("DecodedFrame (%d) > FrameContentSize (%d)\n", d.syncStream.decodedFrame, d.frame.FrameContentSize)
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}
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d.current.err = ErrFrameSizeExceeded
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return false
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}
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// Check FCS
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if d.current.d.Last && d.frame.FrameContentSize != fcsUnknown && d.syncStream.decodedFrame != d.frame.FrameContentSize {
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if debugDecoder {
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printf("DecodedFrame (%d) != FrameContentSize (%d)\n", d.syncStream.decodedFrame, d.frame.FrameContentSize)
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}
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d.current.err = ErrFrameSizeMismatch
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return false
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}
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// Update/Check CRC
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if d.frame.HasCheckSum {
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if !d.o.ignoreChecksum {
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|
d.frame.crc.Write(d.current.b)
|
|
}
|
|
if d.current.d.Last {
|
|
if !d.o.ignoreChecksum {
|
|
d.current.err = d.frame.checkCRC()
|
|
} else {
|
|
d.current.err = d.frame.consumeCRC()
|
|
}
|
|
if d.current.err != nil {
|
|
println("CRC error:", d.current.err)
|
|
return false
|
|
}
|
|
}
|
|
}
|
|
d.syncStream.inFrame = !d.current.d.Last
|
|
}
|
|
return true
|
|
}
|
|
|
|
func (d *Decoder) stashDecoder() {
|
|
if d.current.d != nil {
|
|
if debugDecoder {
|
|
printf("re-adding current decoder %p", d.current.d)
|
|
}
|
|
d.decoders <- d.current.d
|
|
d.current.d = nil
|
|
}
|
|
}
|
|
|
|
// Close will release all resources.
|
|
// It is NOT possible to reuse the decoder after this.
|
|
func (d *Decoder) Close() {
|
|
if d.current.err == ErrDecoderClosed {
|
|
return
|
|
}
|
|
d.drainOutput()
|
|
if d.current.cancel != nil {
|
|
d.current.cancel()
|
|
d.streamWg.Wait()
|
|
d.current.cancel = nil
|
|
}
|
|
if d.decoders != nil {
|
|
close(d.decoders)
|
|
for dec := range d.decoders {
|
|
dec.Close()
|
|
}
|
|
d.decoders = nil
|
|
}
|
|
if d.current.d != nil {
|
|
d.current.d.Close()
|
|
d.current.d = nil
|
|
}
|
|
d.current.err = ErrDecoderClosed
|
|
}
|
|
|
|
// IOReadCloser returns the decoder as an io.ReadCloser for convenience.
|
|
// Any changes to the decoder will be reflected, so the returned ReadCloser
|
|
// can be reused along with the decoder.
|
|
// io.WriterTo is also supported by the returned ReadCloser.
|
|
func (d *Decoder) IOReadCloser() io.ReadCloser {
|
|
return closeWrapper{d: d}
|
|
}
|
|
|
|
// closeWrapper wraps a function call as a closer.
|
|
type closeWrapper struct {
|
|
d *Decoder
|
|
}
|
|
|
|
// WriteTo forwards WriteTo calls to the decoder.
|
|
func (c closeWrapper) WriteTo(w io.Writer) (n int64, err error) {
|
|
return c.d.WriteTo(w)
|
|
}
|
|
|
|
// Read forwards read calls to the decoder.
|
|
func (c closeWrapper) Read(p []byte) (n int, err error) {
|
|
return c.d.Read(p)
|
|
}
|
|
|
|
// Close closes the decoder.
|
|
func (c closeWrapper) Close() error {
|
|
c.d.Close()
|
|
return nil
|
|
}
|
|
|
|
type decodeOutput struct {
|
|
d *blockDec
|
|
b []byte
|
|
err error
|
|
}
|
|
|
|
func (d *Decoder) startSyncDecoder(r io.Reader) error {
|
|
d.frame.history.reset()
|
|
d.syncStream.br = readerWrapper{r: r}
|
|
d.syncStream.inFrame = false
|
|
d.syncStream.enabled = true
|
|
d.syncStream.decodedFrame = 0
|
|
return nil
|
|
}
|
|
|
|
// Create Decoder:
|
|
// ASYNC:
|
|
// Spawn 3 go routines.
|
|
// 0: Read frames and decode block literals.
|
|
// 1: Decode sequences.
|
|
// 2: Execute sequences, send to output.
|
|
func (d *Decoder) startStreamDecoder(ctx context.Context, r io.Reader, output chan decodeOutput) {
|
|
defer d.streamWg.Done()
|
|
br := readerWrapper{r: r}
|
|
|
|
var seqDecode = make(chan *blockDec, d.o.concurrent)
|
|
var seqExecute = make(chan *blockDec, d.o.concurrent)
|
|
|
|
// Async 1: Decode sequences...
|
|
go func() {
|
|
var hist history
|
|
var hasErr bool
|
|
|
|
for block := range seqDecode {
|
|
if hasErr {
|
|
if block != nil {
|
|
seqExecute <- block
|
|
}
|
|
continue
|
|
}
|
|
if block.async.newHist != nil {
|
|
if debugDecoder {
|
|
println("Async 1: new history, recent:", block.async.newHist.recentOffsets)
|
|
}
|
|
hist.reset()
|
|
hist.decoders = block.async.newHist.decoders
|
|
hist.recentOffsets = block.async.newHist.recentOffsets
|
|
hist.windowSize = block.async.newHist.windowSize
|
|
if block.async.newHist.dict != nil {
|
|
hist.setDict(block.async.newHist.dict)
|
|
}
|
|
}
|
|
if block.err != nil || block.Type != blockTypeCompressed {
|
|
hasErr = block.err != nil
|
|
seqExecute <- block
|
|
continue
|
|
}
|
|
|
|
hist.decoders.literals = block.async.literals
|
|
block.err = block.prepareSequences(block.async.seqData, &hist)
|
|
if debugDecoder && block.err != nil {
|
|
println("prepareSequences returned:", block.err)
|
|
}
|
|
hasErr = block.err != nil
|
|
if block.err == nil {
|
|
block.err = block.decodeSequences(&hist)
|
|
if debugDecoder && block.err != nil {
|
|
println("decodeSequences returned:", block.err)
|
|
}
|
|
hasErr = block.err != nil
|
|
// block.async.sequence = hist.decoders.seq[:hist.decoders.nSeqs]
|
|
block.async.seqSize = hist.decoders.seqSize
|
|
}
|
|
seqExecute <- block
|
|
}
|
|
close(seqExecute)
|
|
hist.reset()
|
|
}()
|
|
|
|
var wg sync.WaitGroup
|
|
wg.Add(1)
|
|
|
|
// Async 3: Execute sequences...
|
|
frameHistCache := d.frame.history.b
|
|
go func() {
|
|
var hist history
|
|
var decodedFrame uint64
|
|
var fcs uint64
|
|
var hasErr bool
|
|
for block := range seqExecute {
|
|
out := decodeOutput{err: block.err, d: block}
|
|
if block.err != nil || hasErr {
|
|
hasErr = true
|
|
output <- out
|
|
continue
|
|
}
|
|
if block.async.newHist != nil {
|
|
if debugDecoder {
|
|
println("Async 2: new history")
|
|
}
|
|
hist.reset()
|
|
hist.windowSize = block.async.newHist.windowSize
|
|
hist.allocFrameBuffer = block.async.newHist.allocFrameBuffer
|
|
if block.async.newHist.dict != nil {
|
|
hist.setDict(block.async.newHist.dict)
|
|
}
|
|
|
|
if cap(hist.b) < hist.allocFrameBuffer {
|
|
if cap(frameHistCache) >= hist.allocFrameBuffer {
|
|
hist.b = frameHistCache
|
|
} else {
|
|
hist.b = make([]byte, 0, hist.allocFrameBuffer)
|
|
println("Alloc history sized", hist.allocFrameBuffer)
|
|
}
|
|
}
|
|
hist.b = hist.b[:0]
|
|
fcs = block.async.fcs
|
|
decodedFrame = 0
|
|
}
|
|
do := decodeOutput{err: block.err, d: block}
|
|
switch block.Type {
|
|
case blockTypeRLE:
|
|
if debugDecoder {
|
|
println("add rle block length:", block.RLESize)
|
|
}
|
|
|
|
if cap(block.dst) < int(block.RLESize) {
|
|
if block.lowMem {
|
|
block.dst = make([]byte, block.RLESize)
|
|
} else {
|
|
block.dst = make([]byte, maxCompressedBlockSize)
|
|
}
|
|
}
|
|
block.dst = block.dst[:block.RLESize]
|
|
v := block.data[0]
|
|
for i := range block.dst {
|
|
block.dst[i] = v
|
|
}
|
|
hist.append(block.dst)
|
|
do.b = block.dst
|
|
case blockTypeRaw:
|
|
if debugDecoder {
|
|
println("add raw block length:", len(block.data))
|
|
}
|
|
hist.append(block.data)
|
|
do.b = block.data
|
|
case blockTypeCompressed:
|
|
if debugDecoder {
|
|
println("execute with history length:", len(hist.b), "window:", hist.windowSize)
|
|
}
|
|
hist.decoders.seqSize = block.async.seqSize
|
|
hist.decoders.literals = block.async.literals
|
|
do.err = block.executeSequences(&hist)
|
|
hasErr = do.err != nil
|
|
if debugDecoder && hasErr {
|
|
println("executeSequences returned:", do.err)
|
|
}
|
|
do.b = block.dst
|
|
}
|
|
if !hasErr {
|
|
decodedFrame += uint64(len(do.b))
|
|
if decodedFrame > fcs {
|
|
println("fcs exceeded", block.Last, fcs, decodedFrame)
|
|
do.err = ErrFrameSizeExceeded
|
|
hasErr = true
|
|
} else if block.Last && fcs != fcsUnknown && decodedFrame != fcs {
|
|
do.err = ErrFrameSizeMismatch
|
|
hasErr = true
|
|
} else {
|
|
if debugDecoder {
|
|
println("fcs ok", block.Last, fcs, decodedFrame)
|
|
}
|
|
}
|
|
}
|
|
output <- do
|
|
}
|
|
close(output)
|
|
frameHistCache = hist.b
|
|
wg.Done()
|
|
if debugDecoder {
|
|
println("decoder goroutines finished")
|
|
}
|
|
hist.reset()
|
|
}()
|
|
|
|
var hist history
|
|
decodeStream:
|
|
for {
|
|
var hasErr bool
|
|
hist.reset()
|
|
decodeBlock := func(block *blockDec) {
|
|
if hasErr {
|
|
if block != nil {
|
|
seqDecode <- block
|
|
}
|
|
return
|
|
}
|
|
if block.err != nil || block.Type != blockTypeCompressed {
|
|
hasErr = block.err != nil
|
|
seqDecode <- block
|
|
return
|
|
}
|
|
|
|
remain, err := block.decodeLiterals(block.data, &hist)
|
|
block.err = err
|
|
hasErr = block.err != nil
|
|
if err == nil {
|
|
block.async.literals = hist.decoders.literals
|
|
block.async.seqData = remain
|
|
} else if debugDecoder {
|
|
println("decodeLiterals error:", err)
|
|
}
|
|
seqDecode <- block
|
|
}
|
|
frame := d.frame
|
|
if debugDecoder {
|
|
println("New frame...")
|
|
}
|
|
var historySent bool
|
|
frame.history.reset()
|
|
err := frame.reset(&br)
|
|
if debugDecoder && err != nil {
|
|
println("Frame decoder returned", err)
|
|
}
|
|
if err == nil {
|
|
err = d.setDict(frame)
|
|
}
|
|
if err == nil && d.frame.WindowSize > d.o.maxWindowSize {
|
|
if debugDecoder {
|
|
println("decoder size exceeded, fws:", d.frame.WindowSize, "> mws:", d.o.maxWindowSize)
|
|
}
|
|
|
|
err = ErrDecoderSizeExceeded
|
|
}
|
|
if err != nil {
|
|
select {
|
|
case <-ctx.Done():
|
|
case dec := <-d.decoders:
|
|
dec.sendErr(err)
|
|
decodeBlock(dec)
|
|
}
|
|
break decodeStream
|
|
}
|
|
|
|
// Go through all blocks of the frame.
|
|
for {
|
|
var dec *blockDec
|
|
select {
|
|
case <-ctx.Done():
|
|
break decodeStream
|
|
case dec = <-d.decoders:
|
|
// Once we have a decoder, we MUST return it.
|
|
}
|
|
err := frame.next(dec)
|
|
if !historySent {
|
|
h := frame.history
|
|
if debugDecoder {
|
|
println("Alloc History:", h.allocFrameBuffer)
|
|
}
|
|
hist.reset()
|
|
if h.dict != nil {
|
|
hist.setDict(h.dict)
|
|
}
|
|
dec.async.newHist = &h
|
|
dec.async.fcs = frame.FrameContentSize
|
|
historySent = true
|
|
} else {
|
|
dec.async.newHist = nil
|
|
}
|
|
if debugDecoder && err != nil {
|
|
println("next block returned error:", err)
|
|
}
|
|
dec.err = err
|
|
dec.hasCRC = false
|
|
if dec.Last && frame.HasCheckSum && err == nil {
|
|
crc, err := frame.rawInput.readSmall(4)
|
|
if len(crc) < 4 {
|
|
if err == nil {
|
|
err = io.ErrUnexpectedEOF
|
|
|
|
}
|
|
println("CRC missing?", err)
|
|
dec.err = err
|
|
} else {
|
|
dec.checkCRC = binary.LittleEndian.Uint32(crc)
|
|
dec.hasCRC = true
|
|
if debugDecoder {
|
|
printf("found crc to check: %08x\n", dec.checkCRC)
|
|
}
|
|
}
|
|
}
|
|
err = dec.err
|
|
last := dec.Last
|
|
decodeBlock(dec)
|
|
if err != nil {
|
|
break decodeStream
|
|
}
|
|
if last {
|
|
break
|
|
}
|
|
}
|
|
}
|
|
close(seqDecode)
|
|
wg.Wait()
|
|
hist.reset()
|
|
d.frame.history.b = frameHistCache
|
|
}
|
|
|
|
func (d *Decoder) setDict(frame *frameDec) (err error) {
|
|
dict, ok := d.dicts[frame.DictionaryID]
|
|
if ok {
|
|
if debugDecoder {
|
|
println("setting dict", frame.DictionaryID)
|
|
}
|
|
frame.history.setDict(dict)
|
|
} else if frame.DictionaryID != 0 {
|
|
// A zero or missing dictionary id is ambiguous:
|
|
// either dictionary zero, or no dictionary. In particular,
|
|
// zstd --patch-from uses this id for the source file,
|
|
// so only return an error if the dictionary id is not zero.
|
|
err = ErrUnknownDictionary
|
|
}
|
|
return err
|
|
}
|