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Diffstat (limited to 'vendor/golang.org/x/net/http2/hpack/hpack.go')
-rw-r--r--vendor/golang.org/x/net/http2/hpack/hpack.go496
1 files changed, 0 insertions, 496 deletions
diff --git a/vendor/golang.org/x/net/http2/hpack/hpack.go b/vendor/golang.org/x/net/http2/hpack/hpack.go
deleted file mode 100644
index 166788c..0000000
--- a/vendor/golang.org/x/net/http2/hpack/hpack.go
+++ /dev/null
@@ -1,496 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package hpack implements HPACK, a compression format for
-// efficiently representing HTTP header fields in the context of HTTP/2.
-//
-// See http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-09
-package hpack
-
-import (
- "bytes"
- "errors"
- "fmt"
-)
-
-// A DecodingError is something the spec defines as a decoding error.
-type DecodingError struct {
- Err error
-}
-
-func (de DecodingError) Error() string {
- return fmt.Sprintf("decoding error: %v", de.Err)
-}
-
-// An InvalidIndexError is returned when an encoder references a table
-// entry before the static table or after the end of the dynamic table.
-type InvalidIndexError int
-
-func (e InvalidIndexError) Error() string {
- return fmt.Sprintf("invalid indexed representation index %d", int(e))
-}
-
-// A HeaderField is a name-value pair. Both the name and value are
-// treated as opaque sequences of octets.
-type HeaderField struct {
- Name, Value string
-
- // Sensitive means that this header field should never be
- // indexed.
- Sensitive bool
-}
-
-// IsPseudo reports whether the header field is an http2 pseudo header.
-// That is, it reports whether it starts with a colon.
-// It is not otherwise guaranteed to be a valid pseudo header field,
-// though.
-func (hf HeaderField) IsPseudo() bool {
- return len(hf.Name) != 0 && hf.Name[0] == ':'
-}
-
-func (hf HeaderField) String() string {
- var suffix string
- if hf.Sensitive {
- suffix = " (sensitive)"
- }
- return fmt.Sprintf("header field %q = %q%s", hf.Name, hf.Value, suffix)
-}
-
-// Size returns the size of an entry per RFC 7541 section 4.1.
-func (hf HeaderField) Size() uint32 {
- // http://http2.github.io/http2-spec/compression.html#rfc.section.4.1
- // "The size of the dynamic table is the sum of the size of
- // its entries. The size of an entry is the sum of its name's
- // length in octets (as defined in Section 5.2), its value's
- // length in octets (see Section 5.2), plus 32. The size of
- // an entry is calculated using the length of the name and
- // value without any Huffman encoding applied."
-
- // This can overflow if somebody makes a large HeaderField
- // Name and/or Value by hand, but we don't care, because that
- // won't happen on the wire because the encoding doesn't allow
- // it.
- return uint32(len(hf.Name) + len(hf.Value) + 32)
-}
-
-// A Decoder is the decoding context for incremental processing of
-// header blocks.
-type Decoder struct {
- dynTab dynamicTable
- emit func(f HeaderField)
-
- emitEnabled bool // whether calls to emit are enabled
- maxStrLen int // 0 means unlimited
-
- // buf is the unparsed buffer. It's only written to
- // saveBuf if it was truncated in the middle of a header
- // block. Because it's usually not owned, we can only
- // process it under Write.
- buf []byte // not owned; only valid during Write
-
- // saveBuf is previous data passed to Write which we weren't able
- // to fully parse before. Unlike buf, we own this data.
- saveBuf bytes.Buffer
-}
-
-// NewDecoder returns a new decoder with the provided maximum dynamic
-// table size. The emitFunc will be called for each valid field
-// parsed, in the same goroutine as calls to Write, before Write returns.
-func NewDecoder(maxDynamicTableSize uint32, emitFunc func(f HeaderField)) *Decoder {
- d := &Decoder{
- emit: emitFunc,
- emitEnabled: true,
- }
- d.dynTab.table.init()
- d.dynTab.allowedMaxSize = maxDynamicTableSize
- d.dynTab.setMaxSize(maxDynamicTableSize)
- return d
-}
-
-// ErrStringLength is returned by Decoder.Write when the max string length
-// (as configured by Decoder.SetMaxStringLength) would be violated.
-var ErrStringLength = errors.New("hpack: string too long")
-
-// SetMaxStringLength sets the maximum size of a HeaderField name or
-// value string. If a string exceeds this length (even after any
-// decompression), Write will return ErrStringLength.
-// A value of 0 means unlimited and is the default from NewDecoder.
-func (d *Decoder) SetMaxStringLength(n int) {
- d.maxStrLen = n
-}
-
-// SetEmitFunc changes the callback used when new header fields
-// are decoded.
-// It must be non-nil. It does not affect EmitEnabled.
-func (d *Decoder) SetEmitFunc(emitFunc func(f HeaderField)) {
- d.emit = emitFunc
-}
-
-// SetEmitEnabled controls whether the emitFunc provided to NewDecoder
-// should be called. The default is true.
-//
-// This facility exists to let servers enforce MAX_HEADER_LIST_SIZE
-// while still decoding and keeping in-sync with decoder state, but
-// without doing unnecessary decompression or generating unnecessary
-// garbage for header fields past the limit.
-func (d *Decoder) SetEmitEnabled(v bool) { d.emitEnabled = v }
-
-// EmitEnabled reports whether calls to the emitFunc provided to NewDecoder
-// are currently enabled. The default is true.
-func (d *Decoder) EmitEnabled() bool { return d.emitEnabled }
-
-// TODO: add method *Decoder.Reset(maxSize, emitFunc) to let callers re-use Decoders and their
-// underlying buffers for garbage reasons.
-
-func (d *Decoder) SetMaxDynamicTableSize(v uint32) {
- d.dynTab.setMaxSize(v)
-}
-
-// SetAllowedMaxDynamicTableSize sets the upper bound that the encoded
-// stream (via dynamic table size updates) may set the maximum size
-// to.
-func (d *Decoder) SetAllowedMaxDynamicTableSize(v uint32) {
- d.dynTab.allowedMaxSize = v
-}
-
-type dynamicTable struct {
- // http://http2.github.io/http2-spec/compression.html#rfc.section.2.3.2
- table headerFieldTable
- size uint32 // in bytes
- maxSize uint32 // current maxSize
- allowedMaxSize uint32 // maxSize may go up to this, inclusive
-}
-
-func (dt *dynamicTable) setMaxSize(v uint32) {
- dt.maxSize = v
- dt.evict()
-}
-
-func (dt *dynamicTable) add(f HeaderField) {
- dt.table.addEntry(f)
- dt.size += f.Size()
- dt.evict()
-}
-
-// If we're too big, evict old stuff.
-func (dt *dynamicTable) evict() {
- var n int
- for dt.size > dt.maxSize && n < dt.table.len() {
- dt.size -= dt.table.ents[n].Size()
- n++
- }
- dt.table.evictOldest(n)
-}
-
-func (d *Decoder) maxTableIndex() int {
- // This should never overflow. RFC 7540 Section 6.5.2 limits the size of
- // the dynamic table to 2^32 bytes, where each entry will occupy more than
- // one byte. Further, the staticTable has a fixed, small length.
- return d.dynTab.table.len() + staticTable.len()
-}
-
-func (d *Decoder) at(i uint64) (hf HeaderField, ok bool) {
- // See Section 2.3.3.
- if i == 0 {
- return
- }
- if i <= uint64(staticTable.len()) {
- return staticTable.ents[i-1], true
- }
- if i > uint64(d.maxTableIndex()) {
- return
- }
- // In the dynamic table, newer entries have lower indices.
- // However, dt.ents[0] is the oldest entry. Hence, dt.ents is
- // the reversed dynamic table.
- dt := d.dynTab.table
- return dt.ents[dt.len()-(int(i)-staticTable.len())], true
-}
-
-// Decode decodes an entire block.
-//
-// TODO: remove this method and make it incremental later? This is
-// easier for debugging now.
-func (d *Decoder) DecodeFull(p []byte) ([]HeaderField, error) {
- var hf []HeaderField
- saveFunc := d.emit
- defer func() { d.emit = saveFunc }()
- d.emit = func(f HeaderField) { hf = append(hf, f) }
- if _, err := d.Write(p); err != nil {
- return nil, err
- }
- if err := d.Close(); err != nil {
- return nil, err
- }
- return hf, nil
-}
-
-func (d *Decoder) Close() error {
- if d.saveBuf.Len() > 0 {
- d.saveBuf.Reset()
- return DecodingError{errors.New("truncated headers")}
- }
- return nil
-}
-
-func (d *Decoder) Write(p []byte) (n int, err error) {
- if len(p) == 0 {
- // Prevent state machine CPU attacks (making us redo
- // work up to the point of finding out we don't have
- // enough data)
- return
- }
- // Only copy the data if we have to. Optimistically assume
- // that p will contain a complete header block.
- if d.saveBuf.Len() == 0 {
- d.buf = p
- } else {
- d.saveBuf.Write(p)
- d.buf = d.saveBuf.Bytes()
- d.saveBuf.Reset()
- }
-
- for len(d.buf) > 0 {
- err = d.parseHeaderFieldRepr()
- if err == errNeedMore {
- // Extra paranoia, making sure saveBuf won't
- // get too large. All the varint and string
- // reading code earlier should already catch
- // overlong things and return ErrStringLength,
- // but keep this as a last resort.
- const varIntOverhead = 8 // conservative
- if d.maxStrLen != 0 && int64(len(d.buf)) > 2*(int64(d.maxStrLen)+varIntOverhead) {
- return 0, ErrStringLength
- }
- d.saveBuf.Write(d.buf)
- return len(p), nil
- }
- if err != nil {
- break
- }
- }
- return len(p), err
-}
-
-// errNeedMore is an internal sentinel error value that means the
-// buffer is truncated and we need to read more data before we can
-// continue parsing.
-var errNeedMore = errors.New("need more data")
-
-type indexType int
-
-const (
- indexedTrue indexType = iota
- indexedFalse
- indexedNever
-)
-
-func (v indexType) indexed() bool { return v == indexedTrue }
-func (v indexType) sensitive() bool { return v == indexedNever }
-
-// returns errNeedMore if there isn't enough data available.
-// any other error is fatal.
-// consumes d.buf iff it returns nil.
-// precondition: must be called with len(d.buf) > 0
-func (d *Decoder) parseHeaderFieldRepr() error {
- b := d.buf[0]
- switch {
- case b&128 != 0:
- // Indexed representation.
- // High bit set?
- // http://http2.github.io/http2-spec/compression.html#rfc.section.6.1
- return d.parseFieldIndexed()
- case b&192 == 64:
- // 6.2.1 Literal Header Field with Incremental Indexing
- // 0b10xxxxxx: top two bits are 10
- // http://http2.github.io/http2-spec/compression.html#rfc.section.6.2.1
- return d.parseFieldLiteral(6, indexedTrue)
- case b&240 == 0:
- // 6.2.2 Literal Header Field without Indexing
- // 0b0000xxxx: top four bits are 0000
- // http://http2.github.io/http2-spec/compression.html#rfc.section.6.2.2
- return d.parseFieldLiteral(4, indexedFalse)
- case b&240 == 16:
- // 6.2.3 Literal Header Field never Indexed
- // 0b0001xxxx: top four bits are 0001
- // http://http2.github.io/http2-spec/compression.html#rfc.section.6.2.3
- return d.parseFieldLiteral(4, indexedNever)
- case b&224 == 32:
- // 6.3 Dynamic Table Size Update
- // Top three bits are '001'.
- // http://http2.github.io/http2-spec/compression.html#rfc.section.6.3
- return d.parseDynamicTableSizeUpdate()
- }
-
- return DecodingError{errors.New("invalid encoding")}
-}
-
-// (same invariants and behavior as parseHeaderFieldRepr)
-func (d *Decoder) parseFieldIndexed() error {
- buf := d.buf
- idx, buf, err := readVarInt(7, buf)
- if err != nil {
- return err
- }
- hf, ok := d.at(idx)
- if !ok {
- return DecodingError{InvalidIndexError(idx)}
- }
- d.buf = buf
- return d.callEmit(HeaderField{Name: hf.Name, Value: hf.Value})
-}
-
-// (same invariants and behavior as parseHeaderFieldRepr)
-func (d *Decoder) parseFieldLiteral(n uint8, it indexType) error {
- buf := d.buf
- nameIdx, buf, err := readVarInt(n, buf)
- if err != nil {
- return err
- }
-
- var hf HeaderField
- wantStr := d.emitEnabled || it.indexed()
- if nameIdx > 0 {
- ihf, ok := d.at(nameIdx)
- if !ok {
- return DecodingError{InvalidIndexError(nameIdx)}
- }
- hf.Name = ihf.Name
- } else {
- hf.Name, buf, err = d.readString(buf, wantStr)
- if err != nil {
- return err
- }
- }
- hf.Value, buf, err = d.readString(buf, wantStr)
- if err != nil {
- return err
- }
- d.buf = buf
- if it.indexed() {
- d.dynTab.add(hf)
- }
- hf.Sensitive = it.sensitive()
- return d.callEmit(hf)
-}
-
-func (d *Decoder) callEmit(hf HeaderField) error {
- if d.maxStrLen != 0 {
- if len(hf.Name) > d.maxStrLen || len(hf.Value) > d.maxStrLen {
- return ErrStringLength
- }
- }
- if d.emitEnabled {
- d.emit(hf)
- }
- return nil
-}
-
-// (same invariants and behavior as parseHeaderFieldRepr)
-func (d *Decoder) parseDynamicTableSizeUpdate() error {
- // RFC 7541, sec 4.2: This dynamic table size update MUST occur at the
- // beginning of the first header block following the change to the dynamic table size.
- if d.dynTab.size > 0 {
- return DecodingError{errors.New("dynamic table size update MUST occur at the beginning of a header block")}
- }
-
- buf := d.buf
- size, buf, err := readVarInt(5, buf)
- if err != nil {
- return err
- }
- if size > uint64(d.dynTab.allowedMaxSize) {
- return DecodingError{errors.New("dynamic table size update too large")}
- }
- d.dynTab.setMaxSize(uint32(size))
- d.buf = buf
- return nil
-}
-
-var errVarintOverflow = DecodingError{errors.New("varint integer overflow")}
-
-// readVarInt reads an unsigned variable length integer off the
-// beginning of p. n is the parameter as described in
-// http://http2.github.io/http2-spec/compression.html#rfc.section.5.1.
-//
-// n must always be between 1 and 8.
-//
-// The returned remain buffer is either a smaller suffix of p, or err != nil.
-// The error is errNeedMore if p doesn't contain a complete integer.
-func readVarInt(n byte, p []byte) (i uint64, remain []byte, err error) {
- if n < 1 || n > 8 {
- panic("bad n")
- }
- if len(p) == 0 {
- return 0, p, errNeedMore
- }
- i = uint64(p[0])
- if n < 8 {
- i &= (1 << uint64(n)) - 1
- }
- if i < (1<<uint64(n))-1 {
- return i, p[1:], nil
- }
-
- origP := p
- p = p[1:]
- var m uint64
- for len(p) > 0 {
- b := p[0]
- p = p[1:]
- i += uint64(b&127) << m
- if b&128 == 0 {
- return i, p, nil
- }
- m += 7
- if m >= 63 { // TODO: proper overflow check. making this up.
- return 0, origP, errVarintOverflow
- }
- }
- return 0, origP, errNeedMore
-}
-
-// readString decodes an hpack string from p.
-//
-// wantStr is whether s will be used. If false, decompression and
-// []byte->string garbage are skipped if s will be ignored
-// anyway. This does mean that huffman decoding errors for non-indexed
-// strings past the MAX_HEADER_LIST_SIZE are ignored, but the server
-// is returning an error anyway, and because they're not indexed, the error
-// won't affect the decoding state.
-func (d *Decoder) readString(p []byte, wantStr bool) (s string, remain []byte, err error) {
- if len(p) == 0 {
- return "", p, errNeedMore
- }
- isHuff := p[0]&128 != 0
- strLen, p, err := readVarInt(7, p)
- if err != nil {
- return "", p, err
- }
- if d.maxStrLen != 0 && strLen > uint64(d.maxStrLen) {
- return "", nil, ErrStringLength
- }
- if uint64(len(p)) < strLen {
- return "", p, errNeedMore
- }
- if !isHuff {
- if wantStr {
- s = string(p[:strLen])
- }
- return s, p[strLen:], nil
- }
-
- if wantStr {
- buf := bufPool.Get().(*bytes.Buffer)
- buf.Reset() // don't trust others
- defer bufPool.Put(buf)
- if err := huffmanDecode(buf, d.maxStrLen, p[:strLen]); err != nil {
- buf.Reset()
- return "", nil, err
- }
- s = buf.String()
- buf.Reset() // be nice to GC
- }
- return s, p[strLen:], nil
-}