diff options
Diffstat (limited to 'vendor/golang.org/x/net/http2/hpack')
| -rw-r--r-- | vendor/golang.org/x/net/http2/hpack/encode.go | 240 | ||||
| -rw-r--r-- | vendor/golang.org/x/net/http2/hpack/hpack.go | 504 | ||||
| -rw-r--r-- | vendor/golang.org/x/net/http2/hpack/huffman.go | 222 | ||||
| -rw-r--r-- | vendor/golang.org/x/net/http2/hpack/tables.go | 479 |
4 files changed, 1445 insertions, 0 deletions
diff --git a/vendor/golang.org/x/net/http2/hpack/encode.go b/vendor/golang.org/x/net/http2/hpack/encode.go new file mode 100644 index 00000000..97f17831 --- /dev/null +++ b/vendor/golang.org/x/net/http2/hpack/encode.go @@ -0,0 +1,240 @@ +// 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 + +import ( + "io" +) + +const ( + uint32Max = ^uint32(0) + initialHeaderTableSize = 4096 +) + +type Encoder struct { + dynTab dynamicTable + // minSize is the minimum table size set by + // SetMaxDynamicTableSize after the previous Header Table Size + // Update. + minSize uint32 + // maxSizeLimit is the maximum table size this encoder + // supports. This will protect the encoder from too large + // size. + maxSizeLimit uint32 + // tableSizeUpdate indicates whether "Header Table Size + // Update" is required. + tableSizeUpdate bool + w io.Writer + buf []byte +} + +// NewEncoder returns a new Encoder which performs HPACK encoding. An +// encoded data is written to w. +func NewEncoder(w io.Writer) *Encoder { + e := &Encoder{ + minSize: uint32Max, + maxSizeLimit: initialHeaderTableSize, + tableSizeUpdate: false, + w: w, + } + e.dynTab.table.init() + e.dynTab.setMaxSize(initialHeaderTableSize) + return e +} + +// WriteField encodes f into a single Write to e's underlying Writer. +// This function may also produce bytes for "Header Table Size Update" +// if necessary. If produced, it is done before encoding f. +func (e *Encoder) WriteField(f HeaderField) error { + e.buf = e.buf[:0] + + if e.tableSizeUpdate { + e.tableSizeUpdate = false + if e.minSize < e.dynTab.maxSize { + e.buf = appendTableSize(e.buf, e.minSize) + } + e.minSize = uint32Max + e.buf = appendTableSize(e.buf, e.dynTab.maxSize) + } + + idx, nameValueMatch := e.searchTable(f) + if nameValueMatch { + e.buf = appendIndexed(e.buf, idx) + } else { + indexing := e.shouldIndex(f) + if indexing { + e.dynTab.add(f) + } + + if idx == 0 { + e.buf = appendNewName(e.buf, f, indexing) + } else { + e.buf = appendIndexedName(e.buf, f, idx, indexing) + } + } + n, err := e.w.Write(e.buf) + if err == nil && n != len(e.buf) { + err = io.ErrShortWrite + } + return err +} + +// searchTable searches f in both stable and dynamic header tables. +// The static header table is searched first. Only when there is no +// exact match for both name and value, the dynamic header table is +// then searched. If there is no match, i is 0. If both name and value +// match, i is the matched index and nameValueMatch becomes true. If +// only name matches, i points to that index and nameValueMatch +// becomes false. +func (e *Encoder) searchTable(f HeaderField) (i uint64, nameValueMatch bool) { + i, nameValueMatch = staticTable.search(f) + if nameValueMatch { + return i, true + } + + j, nameValueMatch := e.dynTab.table.search(f) + if nameValueMatch || (i == 0 && j != 0) { + return j + uint64(staticTable.len()), nameValueMatch + } + + return i, false +} + +// SetMaxDynamicTableSize changes the dynamic header table size to v. +// The actual size is bounded by the value passed to +// SetMaxDynamicTableSizeLimit. +func (e *Encoder) SetMaxDynamicTableSize(v uint32) { + if v > e.maxSizeLimit { + v = e.maxSizeLimit + } + if v < e.minSize { + e.minSize = v + } + e.tableSizeUpdate = true + e.dynTab.setMaxSize(v) +} + +// SetMaxDynamicTableSizeLimit changes the maximum value that can be +// specified in SetMaxDynamicTableSize to v. By default, it is set to +// 4096, which is the same size of the default dynamic header table +// size described in HPACK specification. If the current maximum +// dynamic header table size is strictly greater than v, "Header Table +// Size Update" will be done in the next WriteField call and the +// maximum dynamic header table size is truncated to v. +func (e *Encoder) SetMaxDynamicTableSizeLimit(v uint32) { + e.maxSizeLimit = v + if e.dynTab.maxSize > v { + e.tableSizeUpdate = true + e.dynTab.setMaxSize(v) + } +} + +// shouldIndex reports whether f should be indexed. +func (e *Encoder) shouldIndex(f HeaderField) bool { + return !f.Sensitive && f.Size() <= e.dynTab.maxSize +} + +// appendIndexed appends index i, as encoded in "Indexed Header Field" +// representation, to dst and returns the extended buffer. +func appendIndexed(dst []byte, i uint64) []byte { + first := len(dst) + dst = appendVarInt(dst, 7, i) + dst[first] |= 0x80 + return dst +} + +// appendNewName appends f, as encoded in one of "Literal Header field +// - New Name" representation variants, to dst and returns the +// extended buffer. +// +// If f.Sensitive is true, "Never Indexed" representation is used. If +// f.Sensitive is false and indexing is true, "Incremental Indexing" +// representation is used. +func appendNewName(dst []byte, f HeaderField, indexing bool) []byte { + dst = append(dst, encodeTypeByte(indexing, f.Sensitive)) + dst = appendHpackString(dst, f.Name) + return appendHpackString(dst, f.Value) +} + +// appendIndexedName appends f and index i referring indexed name +// entry, as encoded in one of "Literal Header field - Indexed Name" +// representation variants, to dst and returns the extended buffer. +// +// If f.Sensitive is true, "Never Indexed" representation is used. If +// f.Sensitive is false and indexing is true, "Incremental Indexing" +// representation is used. +func appendIndexedName(dst []byte, f HeaderField, i uint64, indexing bool) []byte { + first := len(dst) + var n byte + if indexing { + n = 6 + } else { + n = 4 + } + dst = appendVarInt(dst, n, i) + dst[first] |= encodeTypeByte(indexing, f.Sensitive) + return appendHpackString(dst, f.Value) +} + +// appendTableSize appends v, as encoded in "Header Table Size Update" +// representation, to dst and returns the extended buffer. +func appendTableSize(dst []byte, v uint32) []byte { + first := len(dst) + dst = appendVarInt(dst, 5, uint64(v)) + dst[first] |= 0x20 + return dst +} + +// appendVarInt appends i, as encoded in variable integer form using n +// bit prefix, to dst and returns the extended buffer. +// +// See +// http://http2.github.io/http2-spec/compression.html#integer.representation +func appendVarInt(dst []byte, n byte, i uint64) []byte { + k := uint64((1 << n) - 1) + if i < k { + return append(dst, byte(i)) + } + dst = append(dst, byte(k)) + i -= k + for ; i >= 128; i >>= 7 { + dst = append(dst, byte(0x80|(i&0x7f))) + } + return append(dst, byte(i)) +} + +// appendHpackString appends s, as encoded in "String Literal" +// representation, to dst and returns the extended buffer. +// +// s will be encoded in Huffman codes only when it produces strictly +// shorter byte string. +func appendHpackString(dst []byte, s string) []byte { + huffmanLength := HuffmanEncodeLength(s) + if huffmanLength < uint64(len(s)) { + first := len(dst) + dst = appendVarInt(dst, 7, huffmanLength) + dst = AppendHuffmanString(dst, s) + dst[first] |= 0x80 + } else { + dst = appendVarInt(dst, 7, uint64(len(s))) + dst = append(dst, s...) + } + return dst +} + +// encodeTypeByte returns type byte. If sensitive is true, type byte +// for "Never Indexed" representation is returned. If sensitive is +// false and indexing is true, type byte for "Incremental Indexing" +// representation is returned. Otherwise, type byte for "Without +// Indexing" is returned. +func encodeTypeByte(indexing, sensitive bool) byte { + if sensitive { + return 0x10 + } + if indexing { + return 0x40 + } + return 0 +} diff --git a/vendor/golang.org/x/net/http2/hpack/hpack.go b/vendor/golang.org/x/net/http2/hpack/hpack.go new file mode 100644 index 00000000..85f18a2b --- /dev/null +++ b/vendor/golang.org/x/net/http2/hpack/hpack.go @@ -0,0 +1,504 @@ +// 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 + + firstField bool // processing the first field of the header block +} + +// 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, + firstField: 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 +} + +// Close declares that the decoding is complete and resets the Decoder +// to be reused again for a new header block. If there is any remaining +// data in the decoder's buffer, Close returns an error. +func (d *Decoder) Close() error { + if d.saveBuf.Len() > 0 { + d.saveBuf.Reset() + return DecodingError{errors.New("truncated headers")} + } + d.firstField = true + 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 + } + d.firstField = false + 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.firstField && 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 +} diff --git a/vendor/golang.org/x/net/http2/hpack/huffman.go b/vendor/golang.org/x/net/http2/hpack/huffman.go new file mode 100644 index 00000000..b412a96c --- /dev/null +++ b/vendor/golang.org/x/net/http2/hpack/huffman.go @@ -0,0 +1,222 @@ +// 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 + +import ( + "bytes" + "errors" + "io" + "sync" +) + +var bufPool = sync.Pool{ + New: func() interface{} { return new(bytes.Buffer) }, +} + +// HuffmanDecode decodes the string in v and writes the expanded +// result to w, returning the number of bytes written to w and the +// Write call's return value. At most one Write call is made. +func HuffmanDecode(w io.Writer, v []byte) (int, error) { + buf := bufPool.Get().(*bytes.Buffer) + buf.Reset() + defer bufPool.Put(buf) + if err := huffmanDecode(buf, 0, v); err != nil { + return 0, err + } + return w.Write(buf.Bytes()) +} + +// HuffmanDecodeToString decodes the string in v. +func HuffmanDecodeToString(v []byte) (string, error) { + buf := bufPool.Get().(*bytes.Buffer) + buf.Reset() + defer bufPool.Put(buf) + if err := huffmanDecode(buf, 0, v); err != nil { + return "", err + } + return buf.String(), nil +} + +// ErrInvalidHuffman is returned for errors found decoding +// Huffman-encoded strings. +var ErrInvalidHuffman = errors.New("hpack: invalid Huffman-encoded data") + +// huffmanDecode decodes v to buf. +// If maxLen is greater than 0, attempts to write more to buf than +// maxLen bytes will return ErrStringLength. +func huffmanDecode(buf *bytes.Buffer, maxLen int, v []byte) error { + rootHuffmanNode := getRootHuffmanNode() + n := rootHuffmanNode + // cur is the bit buffer that has not been fed into n. + // cbits is the number of low order bits in cur that are valid. + // sbits is the number of bits of the symbol prefix being decoded. + cur, cbits, sbits := uint(0), uint8(0), uint8(0) + for _, b := range v { + cur = cur<<8 | uint(b) + cbits += 8 + sbits += 8 + for cbits >= 8 { + idx := byte(cur >> (cbits - 8)) + n = n.children[idx] + if n == nil { + return ErrInvalidHuffman + } + if n.children == nil { + if maxLen != 0 && buf.Len() == maxLen { + return ErrStringLength + } + buf.WriteByte(n.sym) + cbits -= n.codeLen + n = rootHuffmanNode + sbits = cbits + } else { + cbits -= 8 + } + } + } + for cbits > 0 { + n = n.children[byte(cur<<(8-cbits))] + if n == nil { + return ErrInvalidHuffman + } + if n.children != nil || n.codeLen > cbits { + break + } + if maxLen != 0 && buf.Len() == maxLen { + return ErrStringLength + } + buf.WriteByte(n.sym) + cbits -= n.codeLen + n = rootHuffmanNode + sbits = cbits + } + if sbits > 7 { + // Either there was an incomplete symbol, or overlong padding. + // Both are decoding errors per RFC 7541 section 5.2. + return ErrInvalidHuffman + } + if mask := uint(1<<cbits - 1); cur&mask != mask { + // Trailing bits must be a prefix of EOS per RFC 7541 section 5.2. + return ErrInvalidHuffman + } + + return nil +} + +type node struct { + // children is non-nil for internal nodes + children *[256]*node + + // The following are only valid if children is nil: + codeLen uint8 // number of bits that led to the output of sym + sym byte // output symbol +} + +func newInternalNode() *node { + return &node{children: new([256]*node)} +} + +var ( + buildRootOnce sync.Once + lazyRootHuffmanNode *node +) + +func getRootHuffmanNode() *node { + buildRootOnce.Do(buildRootHuffmanNode) + return lazyRootHuffmanNode +} + +func buildRootHuffmanNode() { + if len(huffmanCodes) != 256 { + panic("unexpected size") + } + lazyRootHuffmanNode = newInternalNode() + for i, code := range huffmanCodes { + addDecoderNode(byte(i), code, huffmanCodeLen[i]) + } +} + +func addDecoderNode(sym byte, code uint32, codeLen uint8) { + cur := lazyRootHuffmanNode + for codeLen > 8 { + codeLen -= 8 + i := uint8(code >> codeLen) + if cur.children[i] == nil { + cur.children[i] = newInternalNode() + } + cur = cur.children[i] + } + shift := 8 - codeLen + start, end := int(uint8(code<<shift)), int(1<<shift) + for i := start; i < start+end; i++ { + cur.children[i] = &node{sym: sym, codeLen: codeLen} + } +} + +// AppendHuffmanString appends s, as encoded in Huffman codes, to dst +// and returns the extended buffer. +func AppendHuffmanString(dst []byte, s string) []byte { + rembits := uint8(8) + + for i := 0; i < len(s); i++ { + if rembits == 8 { + dst = append(dst, 0) + } + dst, rembits = appendByteToHuffmanCode(dst, rembits, s[i]) + } + + if rembits < 8 { + // special EOS symbol + code := uint32(0x3fffffff) + nbits := uint8(30) + + t := uint8(code >> (nbits - rembits)) + dst[len(dst)-1] |= t + } + + return dst +} + +// HuffmanEncodeLength returns the number of bytes required to encode +// s in Huffman codes. The result is round up to byte boundary. +func HuffmanEncodeLength(s string) uint64 { + n := uint64(0) + for i := 0; i < len(s); i++ { + n += uint64(huffmanCodeLen[s[i]]) + } + return (n + 7) / 8 +} + +// appendByteToHuffmanCode appends Huffman code for c to dst and +// returns the extended buffer and the remaining bits in the last +// element. The appending is not byte aligned and the remaining bits +// in the last element of dst is given in rembits. +func appendByteToHuffmanCode(dst []byte, rembits uint8, c byte) ([]byte, uint8) { + code := huffmanCodes[c] + nbits := huffmanCodeLen[c] + + for { + if rembits > nbits { + t := uint8(code << (rembits - nbits)) + dst[len(dst)-1] |= t + rembits -= nbits + break + } + + t := uint8(code >> (nbits - rembits)) + dst[len(dst)-1] |= t + + nbits -= rembits + rembits = 8 + + if nbits == 0 { + break + } + + dst = append(dst, 0) + } + + return dst, rembits +} diff --git a/vendor/golang.org/x/net/http2/hpack/tables.go b/vendor/golang.org/x/net/http2/hpack/tables.go new file mode 100644 index 00000000..a66cfbea --- /dev/null +++ b/vendor/golang.org/x/net/http2/hpack/tables.go @@ -0,0 +1,479 @@ +// 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 + +import ( + "fmt" +) + +// headerFieldTable implements a list of HeaderFields. +// This is used to implement the static and dynamic tables. +type headerFieldTable struct { + // For static tables, entries are never evicted. + // + // For dynamic tables, entries are evicted from ents[0] and added to the end. + // Each entry has a unique id that starts at one and increments for each + // entry that is added. This unique id is stable across evictions, meaning + // it can be used as a pointer to a specific entry. As in hpack, unique ids + // are 1-based. The unique id for ents[k] is k + evictCount + 1. + // + // Zero is not a valid unique id. + // + // evictCount should not overflow in any remotely practical situation. In + // practice, we will have one dynamic table per HTTP/2 connection. If we + // assume a very powerful server that handles 1M QPS per connection and each + // request adds (then evicts) 100 entries from the table, it would still take + // 2M years for evictCount to overflow. + ents []HeaderField + evictCount uint64 + + // byName maps a HeaderField name to the unique id of the newest entry with + // the same name. See above for a definition of "unique id". + byName map[string]uint64 + + // byNameValue maps a HeaderField name/value pair to the unique id of the newest + // entry with the same name and value. See above for a definition of "unique id". + byNameValue map[pairNameValue]uint64 +} + +type pairNameValue struct { + name, value string +} + +func (t *headerFieldTable) init() { + t.byName = make(map[string]uint64) + t.byNameValue = make(map[pairNameValue]uint64) +} + +// len reports the number of entries in the table. +func (t *headerFieldTable) len() int { + return len(t.ents) +} + +// addEntry adds a new entry. +func (t *headerFieldTable) addEntry(f HeaderField) { + id := uint64(t.len()) + t.evictCount + 1 + t.byName[f.Name] = id + t.byNameValue[pairNameValue{f.Name, f.Value}] = id + t.ents = append(t.ents, f) +} + +// evictOldest evicts the n oldest entries in the table. +func (t *headerFieldTable) evictOldest(n int) { + if n > t.len() { + panic(fmt.Sprintf("evictOldest(%v) on table with %v entries", n, t.len())) + } + for k := 0; k < n; k++ { + f := t.ents[k] + id := t.evictCount + uint64(k) + 1 + if t.byName[f.Name] == id { + delete(t.byName, f.Name) + } + if p := (pairNameValue{f.Name, f.Value}); t.byNameValue[p] == id { + delete(t.byNameValue, p) + } + } + copy(t.ents, t.ents[n:]) + for k := t.len() - n; k < t.len(); k++ { + t.ents[k] = HeaderField{} // so strings can be garbage collected + } + t.ents = t.ents[:t.len()-n] + if t.evictCount+uint64(n) < t.evictCount { + panic("evictCount overflow") + } + t.evictCount += uint64(n) +} + +// search finds f in the table. If there is no match, i is 0. +// If both name and value match, i is the matched index and nameValueMatch +// becomes true. If only name matches, i points to that index and +// nameValueMatch becomes false. +// +// The returned index is a 1-based HPACK index. For dynamic tables, HPACK says +// that index 1 should be the newest entry, but t.ents[0] is the oldest entry, +// meaning t.ents is reversed for dynamic tables. Hence, when t is a dynamic +// table, the return value i actually refers to the entry t.ents[t.len()-i]. +// +// All tables are assumed to be a dynamic tables except for the global +// staticTable pointer. +// +// See Section 2.3.3. +func (t *headerFieldTable) search(f HeaderField) (i uint64, nameValueMatch bool) { + if !f.Sensitive { + if id := t.byNameValue[pairNameValue{f.Name, f.Value}]; id != 0 { + return t.idToIndex(id), true + } + } + if id := t.byName[f.Name]; id != 0 { + return t.idToIndex(id), false + } + return 0, false +} + +// idToIndex converts a unique id to an HPACK index. +// See Section 2.3.3. +func (t *headerFieldTable) idToIndex(id uint64) uint64 { + if id <= t.evictCount { + panic(fmt.Sprintf("id (%v) <= evictCount (%v)", id, t.evictCount)) + } + k := id - t.evictCount - 1 // convert id to an index t.ents[k] + if t != staticTable { + return uint64(t.len()) - k // dynamic table + } + return k + 1 +} + +// http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-07#appendix-B +var staticTable = newStaticTable() +var staticTableEntries = [...]HeaderField{ + {Name: ":authority"}, + {Name: ":method", Value: "GET"}, + {Name: ":method", Value: "POST"}, + {Name: ":path", Value: "/"}, + {Name: ":path", Value: "/index.html"}, + {Name: ":scheme", Value: "http"}, + {Name: ":scheme", Value: "https"}, + {Name: ":status", Value: "200"}, + {Name: ":status", Value: "204"}, + {Name: ":status", Value: "206"}, + {Name: ":status", Value: "304"}, + {Name: ":status", Value: "400"}, + {Name: ":status", Value: "404"}, + {Name: ":status", Value: "500"}, + {Name: "accept-charset"}, + {Name: "accept-encoding", Value: "gzip, deflate"}, + {Name: "accept-language"}, + {Name: "accept-ranges"}, + {Name: "accept"}, + {Name: "access-control-allow-origin"}, + {Name: "age"}, + {Name: "allow"}, + {Name: "authorization"}, + {Name: "cache-control"}, + {Name: "content-disposition"}, + {Name: "content-encoding"}, + {Name: "content-language"}, + {Name: "content-length"}, + {Name: "content-location"}, + {Name: "content-range"}, + {Name: "content-type"}, + {Name: "cookie"}, + {Name: "date"}, + {Name: "etag"}, + {Name: "expect"}, + {Name: "expires"}, + {Name: "from"}, + {Name: "host"}, + {Name: "if-match"}, + {Name: "if-modified-since"}, + {Name: "if-none-match"}, + {Name: "if-range"}, + {Name: "if-unmodified-since"}, + {Name: "last-modified"}, + {Name: "link"}, + {Name: "location"}, + {Name: "max-forwards"}, + {Name: "proxy-authenticate"}, + {Name: "proxy-authorization"}, + {Name: "range"}, + {Name: "referer"}, + {Name: "refresh"}, + {Name: "retry-after"}, + {Name: "server"}, + {Name: "set-cookie"}, + {Name: "strict-transport-security"}, + {Name: "transfer-encoding"}, + {Name: "user-agent"}, + {Name: "vary"}, + {Name: "via"}, + {Name: "www-authenticate"}, +} + +func newStaticTable() *headerFieldTable { + t := &headerFieldTable{} + t.init() + for _, e := range staticTableEntries[:] { + t.addEntry(e) + } + return t +} + +var huffmanCodes = [256]uint32{ + 0x1ff8, + 0x7fffd8, + 0xfffffe2, + 0xfffffe3, + 0xfffffe4, + 0xfffffe5, + 0xfffffe6, + 0xfffffe7, + 0xfffffe8, + 0xffffea, + 0x3ffffffc, + 0xfffffe9, + 0xfffffea, + 0x3ffffffd, + 0xfffffeb, + 0xfffffec, + 0xfffffed, + 0xfffffee, + 0xfffffef, + 0xffffff0, + 0xffffff1, + 0xffffff2, + 0x3ffffffe, + 0xffffff3, + 0xffffff4, + 0xffffff5, + 0xffffff6, + 0xffffff7, + 0xffffff8, + 0xffffff9, + 0xffffffa, + 0xffffffb, + 0x14, + 0x3f8, + 0x3f9, + 0xffa, + 0x1ff9, + 0x15, + 0xf8, + 0x7fa, + 0x3fa, + 0x3fb, + 0xf9, + 0x7fb, + 0xfa, + 0x16, + 0x17, + 0x18, + 0x0, + 0x1, + 0x2, + 0x19, + 0x1a, + 0x1b, + 0x1c, + 0x1d, + 0x1e, + 0x1f, + 0x5c, + 0xfb, + 0x7ffc, + 0x20, + 0xffb, + 0x3fc, + 0x1ffa, + 0x21, + 0x5d, + 0x5e, + 0x5f, + 0x60, + 0x61, + 0x62, + 0x63, + 0x64, + 0x65, + 0x66, + 0x67, + 0x68, + 0x69, + 0x6a, + 0x6b, + 0x6c, + 0x6d, + 0x6e, + 0x6f, + 0x70, + 0x71, + 0x72, + 0xfc, + 0x73, + 0xfd, + 0x1ffb, + 0x7fff0, + 0x1ffc, + 0x3ffc, + 0x22, + 0x7ffd, + 0x3, + 0x23, + 0x4, + 0x24, + 0x5, + 0x25, + 0x26, + 0x27, + 0x6, + 0x74, + 0x75, + 0x28, + 0x29, + 0x2a, + 0x7, + 0x2b, + 0x76, + 0x2c, + 0x8, + 0x9, + 0x2d, + 0x77, + 0x78, + 0x79, + 0x7a, + 0x7b, + 0x7ffe, + 0x7fc, + 0x3ffd, + 0x1ffd, + 0xffffffc, + 0xfffe6, + 0x3fffd2, + 0xfffe7, + 0xfffe8, + 0x3fffd3, + 0x3fffd4, + 0x3fffd5, + 0x7fffd9, + 0x3fffd6, + 0x7fffda, + 0x7fffdb, + 0x7fffdc, + 0x7fffdd, + 0x7fffde, + 0xffffeb, + 0x7fffdf, + 0xffffec, + 0xffffed, + 0x3fffd7, + 0x7fffe0, + 0xffffee, + 0x7fffe1, + 0x7fffe2, + 0x7fffe3, + 0x7fffe4, + 0x1fffdc, + 0x3fffd8, + 0x7fffe5, + 0x3fffd9, + 0x7fffe6, + 0x7fffe7, + 0xffffef, + 0x3fffda, + 0x1fffdd, + 0xfffe9, + 0x3fffdb, + 0x3fffdc, + 0x7fffe8, + 0x7fffe9, + 0x1fffde, + 0x7fffea, + 0x3fffdd, + 0x3fffde, + 0xfffff0, + 0x1fffdf, + 0x3fffdf, + 0x7fffeb, + 0x7fffec, + 0x1fffe0, + 0x1fffe1, + 0x3fffe0, + 0x1fffe2, + 0x7fffed, + 0x3fffe1, + 0x7fffee, + 0x7fffef, + 0xfffea, + 0x3fffe2, + 0x3fffe3, + 0x3fffe4, + 0x7ffff0, + 0x3fffe5, + 0x3fffe6, + 0x7ffff1, + 0x3ffffe0, + 0x3ffffe1, + 0xfffeb, + 0x7fff1, + 0x3fffe7, + 0x7ffff2, + 0x3fffe8, + 0x1ffffec, + 0x3ffffe2, + 0x3ffffe3, + 0x3ffffe4, + 0x7ffffde, + 0x7ffffdf, + 0x3ffffe5, + 0xfffff1, + 0x1ffffed, + 0x7fff2, + 0x1fffe3, + 0x3ffffe6, + 0x7ffffe0, + 0x7ffffe1, + 0x3ffffe7, + 0x7ffffe2, + 0xfffff2, + 0x1fffe4, + 0x1fffe5, + 0x3ffffe8, + 0x3ffffe9, + 0xffffffd, + 0x7ffffe3, + 0x7ffffe4, + 0x7ffffe5, + 0xfffec, + 0xfffff3, + 0xfffed, + 0x1fffe6, + 0x3fffe9, + 0x1fffe7, + 0x1fffe8, + 0x7ffff3, + 0x3fffea, + 0x3fffeb, + 0x1ffffee, + 0x1ffffef, + 0xfffff4, + 0xfffff5, + 0x3ffffea, + 0x7ffff4, + 0x3ffffeb, + 0x7ffffe6, + 0x3ffffec, + 0x3ffffed, + 0x7ffffe7, + 0x7ffffe8, + 0x7ffffe9, + 0x7ffffea, + 0x7ffffeb, + 0xffffffe, + 0x7ffffec, + 0x7ffffed, + 0x7ffffee, + 0x7ffffef, + 0x7fffff0, + 0x3ffffee, +} + +var huffmanCodeLen = [256]uint8{ + 13, 23, 28, 28, 28, 28, 28, 28, 28, 24, 30, 28, 28, 30, 28, 28, + 28, 28, 28, 28, 28, 28, 30, 28, 28, 28, 28, 28, 28, 28, 28, 28, + 6, 10, 10, 12, 13, 6, 8, 11, 10, 10, 8, 11, 8, 6, 6, 6, + 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 15, 6, 12, 10, + 13, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 8, 7, 8, 13, 19, 13, 14, 6, + 15, 5, 6, 5, 6, 5, 6, 6, 6, 5, 7, 7, 6, 6, 6, 5, + 6, 7, 6, 5, 5, 6, 7, 7, 7, 7, 7, 15, 11, 14, 13, 28, + 20, 22, 20, 20, 22, 22, 22, 23, 22, 23, 23, 23, 23, 23, 24, 23, + 24, 24, 22, 23, 24, 23, 23, 23, 23, 21, 22, 23, 22, 23, 23, 24, + 22, 21, 20, 22, 22, 23, 23, 21, 23, 22, 22, 24, 21, 22, 23, 23, + 21, 21, 22, 21, 23, 22, 23, 23, 20, 22, 22, 22, 23, 22, 22, 23, + 26, 26, 20, 19, 22, 23, 22, 25, 26, 26, 26, 27, 27, 26, 24, 25, + 19, 21, 26, 27, 27, 26, 27, 24, 21, 21, 26, 26, 28, 27, 27, 27, + 20, 24, 20, 21, 22, 21, 21, 23, 22, 22, 25, 25, 24, 24, 26, 23, + 26, 27, 26, 26, 27, 27, 27, 27, 27, 28, 27, 27, 27, 27, 27, 26, +} |