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Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>
This commit is contained in:
Alex Ellis (OpenFaaS Ltd)
2019-12-20 12:56:11 +00:00
parent 9a30ff517f
commit 5c45242b3d
1379 changed files with 633020 additions and 0 deletions
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240
vendor/golang.org/x/net/http2/hpack/encode.go generated vendored Normal file
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// 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
}

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vendor/golang.org/x/net/http2/hpack/hpack.go generated vendored Normal file
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// 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
}

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vendor/golang.org/x/net/http2/hpack/huffman.go generated vendored Normal file
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// 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
}

479
vendor/golang.org/x/net/http2/hpack/tables.go generated vendored Normal file
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@ -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,
}