bsc/vendor/github.com/syndtr/goleveldb/leveldb/table/writer.go
Péter Szilágyi 289b30715d Godeps, vendor: convert dependency management to trash (#3198)
This commit converts the dependency management from Godeps to the vendor
folder, also switching the tool from godep to trash. Since the upstream tool
lacks a few features proposed via a few PRs, until those PRs are merged in
(if), use github.com/karalabe/trash.

You can update dependencies via trash --update.

All dependencies have been updated to their latest version.

Parts of the build system are reworked to drop old notions of Godeps and
invocation of the go vet command so that it doesn't run against the vendor
folder, as that will just blow up during vetting.

The conversion drops OpenCL (and hence GPU mining support) from ethash and our
codebase. The short reasoning is that there's noone to maintain and having
opencl libs in our deps messes up builds as go install ./... tries to build
them, failing with unsatisfied link errors for the C OpenCL deps.

golang.org/x/net/context is not vendored in. We expect it to be fetched by the
user (i.e. using go get). To keep ci.go builds reproducible the package is
"vendored" in build/_vendor.
2016-10-28 19:05:01 +02:00

376 lines
8.8 KiB
Go

// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
// All rights reserved.
//
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package table
import (
"encoding/binary"
"errors"
"fmt"
"io"
"github.com/golang/snappy"
"github.com/syndtr/goleveldb/leveldb/comparer"
"github.com/syndtr/goleveldb/leveldb/filter"
"github.com/syndtr/goleveldb/leveldb/opt"
"github.com/syndtr/goleveldb/leveldb/util"
)
func sharedPrefixLen(a, b []byte) int {
i, n := 0, len(a)
if n > len(b) {
n = len(b)
}
for i < n && a[i] == b[i] {
i++
}
return i
}
type blockWriter struct {
restartInterval int
buf util.Buffer
nEntries int
prevKey []byte
restarts []uint32
scratch []byte
}
func (w *blockWriter) append(key, value []byte) {
nShared := 0
if w.nEntries%w.restartInterval == 0 {
w.restarts = append(w.restarts, uint32(w.buf.Len()))
} else {
nShared = sharedPrefixLen(w.prevKey, key)
}
n := binary.PutUvarint(w.scratch[0:], uint64(nShared))
n += binary.PutUvarint(w.scratch[n:], uint64(len(key)-nShared))
n += binary.PutUvarint(w.scratch[n:], uint64(len(value)))
w.buf.Write(w.scratch[:n])
w.buf.Write(key[nShared:])
w.buf.Write(value)
w.prevKey = append(w.prevKey[:0], key...)
w.nEntries++
}
func (w *blockWriter) finish() {
// Write restarts entry.
if w.nEntries == 0 {
// Must have at least one restart entry.
w.restarts = append(w.restarts, 0)
}
w.restarts = append(w.restarts, uint32(len(w.restarts)))
for _, x := range w.restarts {
buf4 := w.buf.Alloc(4)
binary.LittleEndian.PutUint32(buf4, x)
}
}
func (w *blockWriter) reset() {
w.buf.Reset()
w.nEntries = 0
w.restarts = w.restarts[:0]
}
func (w *blockWriter) bytesLen() int {
restartsLen := len(w.restarts)
if restartsLen == 0 {
restartsLen = 1
}
return w.buf.Len() + 4*restartsLen + 4
}
type filterWriter struct {
generator filter.FilterGenerator
buf util.Buffer
nKeys int
offsets []uint32
}
func (w *filterWriter) add(key []byte) {
if w.generator == nil {
return
}
w.generator.Add(key)
w.nKeys++
}
func (w *filterWriter) flush(offset uint64) {
if w.generator == nil {
return
}
for x := int(offset / filterBase); x > len(w.offsets); {
w.generate()
}
}
func (w *filterWriter) finish() {
if w.generator == nil {
return
}
// Generate last keys.
if w.nKeys > 0 {
w.generate()
}
w.offsets = append(w.offsets, uint32(w.buf.Len()))
for _, x := range w.offsets {
buf4 := w.buf.Alloc(4)
binary.LittleEndian.PutUint32(buf4, x)
}
w.buf.WriteByte(filterBaseLg)
}
func (w *filterWriter) generate() {
// Record offset.
w.offsets = append(w.offsets, uint32(w.buf.Len()))
// Generate filters.
if w.nKeys > 0 {
w.generator.Generate(&w.buf)
w.nKeys = 0
}
}
// Writer is a table writer.
type Writer struct {
writer io.Writer
err error
// Options
cmp comparer.Comparer
filter filter.Filter
compression opt.Compression
blockSize int
dataBlock blockWriter
indexBlock blockWriter
filterBlock filterWriter
pendingBH blockHandle
offset uint64
nEntries int
// Scratch allocated enough for 5 uvarint. Block writer should not use
// first 20-bytes since it will be used to encode block handle, which
// then passed to the block writer itself.
scratch [50]byte
comparerScratch []byte
compressionScratch []byte
}
func (w *Writer) writeBlock(buf *util.Buffer, compression opt.Compression) (bh blockHandle, err error) {
// Compress the buffer if necessary.
var b []byte
if compression == opt.SnappyCompression {
// Allocate scratch enough for compression and block trailer.
if n := snappy.MaxEncodedLen(buf.Len()) + blockTrailerLen; len(w.compressionScratch) < n {
w.compressionScratch = make([]byte, n)
}
compressed := snappy.Encode(w.compressionScratch, buf.Bytes())
n := len(compressed)
b = compressed[:n+blockTrailerLen]
b[n] = blockTypeSnappyCompression
} else {
tmp := buf.Alloc(blockTrailerLen)
tmp[0] = blockTypeNoCompression
b = buf.Bytes()
}
// Calculate the checksum.
n := len(b) - 4
checksum := util.NewCRC(b[:n]).Value()
binary.LittleEndian.PutUint32(b[n:], checksum)
// Write the buffer to the file.
_, err = w.writer.Write(b)
if err != nil {
return
}
bh = blockHandle{w.offset, uint64(len(b) - blockTrailerLen)}
w.offset += uint64(len(b))
return
}
func (w *Writer) flushPendingBH(key []byte) {
if w.pendingBH.length == 0 {
return
}
var separator []byte
if len(key) == 0 {
separator = w.cmp.Successor(w.comparerScratch[:0], w.dataBlock.prevKey)
} else {
separator = w.cmp.Separator(w.comparerScratch[:0], w.dataBlock.prevKey, key)
}
if separator == nil {
separator = w.dataBlock.prevKey
} else {
w.comparerScratch = separator
}
n := encodeBlockHandle(w.scratch[:20], w.pendingBH)
// Append the block handle to the index block.
w.indexBlock.append(separator, w.scratch[:n])
// Reset prev key of the data block.
w.dataBlock.prevKey = w.dataBlock.prevKey[:0]
// Clear pending block handle.
w.pendingBH = blockHandle{}
}
func (w *Writer) finishBlock() error {
w.dataBlock.finish()
bh, err := w.writeBlock(&w.dataBlock.buf, w.compression)
if err != nil {
return err
}
w.pendingBH = bh
// Reset the data block.
w.dataBlock.reset()
// Flush the filter block.
w.filterBlock.flush(w.offset)
return nil
}
// Append appends key/value pair to the table. The keys passed must
// be in increasing order.
//
// It is safe to modify the contents of the arguments after Append returns.
func (w *Writer) Append(key, value []byte) error {
if w.err != nil {
return w.err
}
if w.nEntries > 0 && w.cmp.Compare(w.dataBlock.prevKey, key) >= 0 {
w.err = fmt.Errorf("leveldb/table: Writer: keys are not in increasing order: %q, %q", w.dataBlock.prevKey, key)
return w.err
}
w.flushPendingBH(key)
// Append key/value pair to the data block.
w.dataBlock.append(key, value)
// Add key to the filter block.
w.filterBlock.add(key)
// Finish the data block if block size target reached.
if w.dataBlock.bytesLen() >= w.blockSize {
if err := w.finishBlock(); err != nil {
w.err = err
return w.err
}
}
w.nEntries++
return nil
}
// BlocksLen returns number of blocks written so far.
func (w *Writer) BlocksLen() int {
n := w.indexBlock.nEntries
if w.pendingBH.length > 0 {
// Includes the pending block.
n++
}
return n
}
// EntriesLen returns number of entries added so far.
func (w *Writer) EntriesLen() int {
return w.nEntries
}
// BytesLen returns number of bytes written so far.
func (w *Writer) BytesLen() int {
return int(w.offset)
}
// Close will finalize the table. Calling Append is not possible
// after Close, but calling BlocksLen, EntriesLen and BytesLen
// is still possible.
func (w *Writer) Close() error {
if w.err != nil {
return w.err
}
// Write the last data block. Or empty data block if there
// aren't any data blocks at all.
if w.dataBlock.nEntries > 0 || w.nEntries == 0 {
if err := w.finishBlock(); err != nil {
w.err = err
return w.err
}
}
w.flushPendingBH(nil)
// Write the filter block.
var filterBH blockHandle
w.filterBlock.finish()
if buf := &w.filterBlock.buf; buf.Len() > 0 {
filterBH, w.err = w.writeBlock(buf, opt.NoCompression)
if w.err != nil {
return w.err
}
}
// Write the metaindex block.
if filterBH.length > 0 {
key := []byte("filter." + w.filter.Name())
n := encodeBlockHandle(w.scratch[:20], filterBH)
w.dataBlock.append(key, w.scratch[:n])
}
w.dataBlock.finish()
metaindexBH, err := w.writeBlock(&w.dataBlock.buf, w.compression)
if err != nil {
w.err = err
return w.err
}
// Write the index block.
w.indexBlock.finish()
indexBH, err := w.writeBlock(&w.indexBlock.buf, w.compression)
if err != nil {
w.err = err
return w.err
}
// Write the table footer.
footer := w.scratch[:footerLen]
for i := range footer {
footer[i] = 0
}
n := encodeBlockHandle(footer, metaindexBH)
encodeBlockHandle(footer[n:], indexBH)
copy(footer[footerLen-len(magic):], magic)
if _, err := w.writer.Write(footer); err != nil {
w.err = err
return w.err
}
w.offset += footerLen
w.err = errors.New("leveldb/table: writer is closed")
return nil
}
// NewWriter creates a new initialized table writer for the file.
//
// Table writer is not safe for concurrent use.
func NewWriter(f io.Writer, o *opt.Options) *Writer {
w := &Writer{
writer: f,
cmp: o.GetComparer(),
filter: o.GetFilter(),
compression: o.GetCompression(),
blockSize: o.GetBlockSize(),
comparerScratch: make([]byte, 0),
}
// data block
w.dataBlock.restartInterval = o.GetBlockRestartInterval()
// The first 20-bytes are used for encoding block handle.
w.dataBlock.scratch = w.scratch[20:]
// index block
w.indexBlock.restartInterval = 1
w.indexBlock.scratch = w.scratch[20:]
// filter block
if w.filter != nil {
w.filterBlock.generator = w.filter.NewGenerator()
w.filterBlock.flush(0)
}
return w
}