syncthing/vendor/github.com/syndtr/goleveldb/leveldb/opt/options.go
Jakob Borg 65aaa607ab Use Go 1.5 vendoring instead of Godeps
Change made by:

- running "gvt fetch" on each of the packages mentioned in
  Godeps/Godeps.json
- `rm -rf Godeps`
- tweaking the build scripts to not mention Godeps
- tweaking the build scripts to test `./lib/...`, `./cmd/...` explicitly
  (to avoid testing vendor)
- tweaking the build scripts to not juggle GOPATH for Godeps and instead
  set GO15VENDOREXPERIMENT.

This also results in some updated packages at the same time I bet.

Building with Go 1.3 and 1.4 still *works* but won't use our vendored
dependencies - the user needs to have the actual packages in their
GOPATH then, which they'll get with a normal "go get". Building with Go
1.6+ will get our vendored dependencies by default even when not using
our build script, which is nice.

By doing this we gain some freedom in that we can pick and choose
manually what to include in vendor, as it's not based on just dependency
analysis of our own code. This is also a risk as we might pick up
dependencies we are unaware of, as the build may work locally with those
packages present in GOPATH. On the other hand the build server will
detect this as it has no packages in it's GOPATH beyond what is included
in the repo.

Recommended tool to manage dependencies is github.com/FiloSottile/gvt.
2016-03-05 21:21:24 +01:00

661 lines
18 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 opt provides sets of options used by LevelDB.
package opt
import (
"math"
"github.com/syndtr/goleveldb/leveldb/cache"
"github.com/syndtr/goleveldb/leveldb/comparer"
"github.com/syndtr/goleveldb/leveldb/filter"
)
const (
KiB = 1024
MiB = KiB * 1024
GiB = MiB * 1024
)
var (
DefaultBlockCacher = LRUCacher
DefaultBlockCacheCapacity = 8 * MiB
DefaultBlockRestartInterval = 16
DefaultBlockSize = 4 * KiB
DefaultCompactionExpandLimitFactor = 25
DefaultCompactionGPOverlapsFactor = 10
DefaultCompactionL0Trigger = 4
DefaultCompactionSourceLimitFactor = 1
DefaultCompactionTableSize = 2 * MiB
DefaultCompactionTableSizeMultiplier = 1.0
DefaultCompactionTotalSize = 10 * MiB
DefaultCompactionTotalSizeMultiplier = 10.0
DefaultCompressionType = SnappyCompression
DefaultIteratorSamplingRate = 1 * MiB
DefaultOpenFilesCacher = LRUCacher
DefaultOpenFilesCacheCapacity = 500
DefaultWriteBuffer = 4 * MiB
DefaultWriteL0PauseTrigger = 12
DefaultWriteL0SlowdownTrigger = 8
)
// Cacher is a caching algorithm.
type Cacher interface {
New(capacity int) cache.Cacher
}
type CacherFunc struct {
NewFunc func(capacity int) cache.Cacher
}
func (f *CacherFunc) New(capacity int) cache.Cacher {
if f.NewFunc != nil {
return f.NewFunc(capacity)
}
return nil
}
func noCacher(int) cache.Cacher { return nil }
var (
// LRUCacher is the LRU-cache algorithm.
LRUCacher = &CacherFunc{cache.NewLRU}
// NoCacher is the value to disable caching algorithm.
NoCacher = &CacherFunc{}
)
// Compression is the 'sorted table' block compression algorithm to use.
type Compression uint
func (c Compression) String() string {
switch c {
case DefaultCompression:
return "default"
case NoCompression:
return "none"
case SnappyCompression:
return "snappy"
}
return "invalid"
}
const (
DefaultCompression Compression = iota
NoCompression
SnappyCompression
nCompression
)
// Strict is the DB 'strict level'.
type Strict uint
const (
// If present then a corrupted or invalid chunk or block in manifest
// journal will cause an error instead of being dropped.
// This will prevent database with corrupted manifest to be opened.
StrictManifest Strict = 1 << iota
// If present then journal chunk checksum will be verified.
StrictJournalChecksum
// If present then a corrupted or invalid chunk or block in journal
// will cause an error instead of being dropped.
// This will prevent database with corrupted journal to be opened.
StrictJournal
// If present then 'sorted table' block checksum will be verified.
// This has effect on both 'read operation' and compaction.
StrictBlockChecksum
// If present then a corrupted 'sorted table' will fails compaction.
// The database will enter read-only mode.
StrictCompaction
// If present then a corrupted 'sorted table' will halts 'read operation'.
StrictReader
// If present then leveldb.Recover will drop corrupted 'sorted table'.
StrictRecovery
// This only applicable for ReadOptions, if present then this ReadOptions
// 'strict level' will override global ones.
StrictOverride
// StrictAll enables all strict flags.
StrictAll = StrictManifest | StrictJournalChecksum | StrictJournal | StrictBlockChecksum | StrictCompaction | StrictReader | StrictRecovery
// DefaultStrict is the default strict flags. Specify any strict flags
// will override default strict flags as whole (i.e. not OR'ed).
DefaultStrict = StrictJournalChecksum | StrictBlockChecksum | StrictCompaction | StrictReader
// NoStrict disables all strict flags. Override default strict flags.
NoStrict = ^StrictAll
)
// Options holds the optional parameters for the DB at large.
type Options struct {
// AltFilters defines one or more 'alternative filters'.
// 'alternative filters' will be used during reads if a filter block
// does not match with the 'effective filter'.
//
// The default value is nil
AltFilters []filter.Filter
// BlockCacher provides cache algorithm for LevelDB 'sorted table' block caching.
// Specify NoCacher to disable caching algorithm.
//
// The default value is LRUCacher.
BlockCacher Cacher
// BlockCacheCapacity defines the capacity of the 'sorted table' block caching.
// Use -1 for zero, this has same effect as specifying NoCacher to BlockCacher.
//
// The default value is 8MiB.
BlockCacheCapacity int
// BlockRestartInterval is the number of keys between restart points for
// delta encoding of keys.
//
// The default value is 16.
BlockRestartInterval int
// BlockSize is the minimum uncompressed size in bytes of each 'sorted table'
// block.
//
// The default value is 4KiB.
BlockSize int
// CompactionExpandLimitFactor limits compaction size after expanded.
// This will be multiplied by table size limit at compaction target level.
//
// The default value is 25.
CompactionExpandLimitFactor int
// CompactionGPOverlapsFactor limits overlaps in grandparent (Level + 2) that a
// single 'sorted table' generates.
// This will be multiplied by table size limit at grandparent level.
//
// The default value is 10.
CompactionGPOverlapsFactor int
// CompactionL0Trigger defines number of 'sorted table' at level-0 that will
// trigger compaction.
//
// The default value is 4.
CompactionL0Trigger int
// CompactionSourceLimitFactor limits compaction source size. This doesn't apply to
// level-0.
// This will be multiplied by table size limit at compaction target level.
//
// The default value is 1.
CompactionSourceLimitFactor int
// CompactionTableSize limits size of 'sorted table' that compaction generates.
// The limits for each level will be calculated as:
// CompactionTableSize * (CompactionTableSizeMultiplier ^ Level)
// The multiplier for each level can also fine-tuned using CompactionTableSizeMultiplierPerLevel.
//
// The default value is 2MiB.
CompactionTableSize int
// CompactionTableSizeMultiplier defines multiplier for CompactionTableSize.
//
// The default value is 1.
CompactionTableSizeMultiplier float64
// CompactionTableSizeMultiplierPerLevel defines per-level multiplier for
// CompactionTableSize.
// Use zero to skip a level.
//
// The default value is nil.
CompactionTableSizeMultiplierPerLevel []float64
// CompactionTotalSize limits total size of 'sorted table' for each level.
// The limits for each level will be calculated as:
// CompactionTotalSize * (CompactionTotalSizeMultiplier ^ Level)
// The multiplier for each level can also fine-tuned using
// CompactionTotalSizeMultiplierPerLevel.
//
// The default value is 10MiB.
CompactionTotalSize int
// CompactionTotalSizeMultiplier defines multiplier for CompactionTotalSize.
//
// The default value is 10.
CompactionTotalSizeMultiplier float64
// CompactionTotalSizeMultiplierPerLevel defines per-level multiplier for
// CompactionTotalSize.
// Use zero to skip a level.
//
// The default value is nil.
CompactionTotalSizeMultiplierPerLevel []float64
// Comparer defines a total ordering over the space of []byte keys: a 'less
// than' relationship. The same comparison algorithm must be used for reads
// and writes over the lifetime of the DB.
//
// The default value uses the same ordering as bytes.Compare.
Comparer comparer.Comparer
// Compression defines the 'sorted table' block compression to use.
//
// The default value (DefaultCompression) uses snappy compression.
Compression Compression
// DisableBufferPool allows disable use of util.BufferPool functionality.
//
// The default value is false.
DisableBufferPool bool
// DisableBlockCache allows disable use of cache.Cache functionality on
// 'sorted table' block.
//
// The default value is false.
DisableBlockCache bool
// DisableCompactionBackoff allows disable compaction retry backoff.
//
// The default value is false.
DisableCompactionBackoff bool
// DisableLargeBatchTransaction allows disabling switch-to-transaction mode
// on large batch write. If enable batch writes large than WriteBuffer will
// use transaction.
//
// The default is false.
DisableLargeBatchTransaction bool
// ErrorIfExist defines whether an error should returned if the DB already
// exist.
//
// The default value is false.
ErrorIfExist bool
// ErrorIfMissing defines whether an error should returned if the DB is
// missing. If false then the database will be created if missing, otherwise
// an error will be returned.
//
// The default value is false.
ErrorIfMissing bool
// Filter defines an 'effective filter' to use. An 'effective filter'
// if defined will be used to generate per-table filter block.
// The filter name will be stored on disk.
// During reads LevelDB will try to find matching filter from
// 'effective filter' and 'alternative filters'.
//
// Filter can be changed after a DB has been created. It is recommended
// to put old filter to the 'alternative filters' to mitigate lack of
// filter during transition period.
//
// A filter is used to reduce disk reads when looking for a specific key.
//
// The default value is nil.
Filter filter.Filter
// IteratorSamplingRate defines approximate gap (in bytes) between read
// sampling of an iterator. The samples will be used to determine when
// compaction should be triggered.
//
// The default is 1MiB.
IteratorSamplingRate int
// NoSync allows completely disable fsync.
//
// The default is false.
NoSync bool
// OpenFilesCacher provides cache algorithm for open files caching.
// Specify NoCacher to disable caching algorithm.
//
// The default value is LRUCacher.
OpenFilesCacher Cacher
// OpenFilesCacheCapacity defines the capacity of the open files caching.
// Use -1 for zero, this has same effect as specifying NoCacher to OpenFilesCacher.
//
// The default value is 500.
OpenFilesCacheCapacity int
// If true then opens DB in read-only mode.
//
// The default value is false.
ReadOnly bool
// Strict defines the DB strict level.
Strict Strict
// WriteBuffer defines maximum size of a 'memdb' before flushed to
// 'sorted table'. 'memdb' is an in-memory DB backed by an on-disk
// unsorted journal.
//
// LevelDB may held up to two 'memdb' at the same time.
//
// The default value is 4MiB.
WriteBuffer int
// WriteL0StopTrigger defines number of 'sorted table' at level-0 that will
// pause write.
//
// The default value is 12.
WriteL0PauseTrigger int
// WriteL0SlowdownTrigger defines number of 'sorted table' at level-0 that
// will trigger write slowdown.
//
// The default value is 8.
WriteL0SlowdownTrigger int
}
func (o *Options) GetAltFilters() []filter.Filter {
if o == nil {
return nil
}
return o.AltFilters
}
func (o *Options) GetBlockCacher() Cacher {
if o == nil || o.BlockCacher == nil {
return DefaultBlockCacher
} else if o.BlockCacher == NoCacher {
return nil
}
return o.BlockCacher
}
func (o *Options) GetBlockCacheCapacity() int {
if o == nil || o.BlockCacheCapacity == 0 {
return DefaultBlockCacheCapacity
} else if o.BlockCacheCapacity < 0 {
return 0
}
return o.BlockCacheCapacity
}
func (o *Options) GetBlockRestartInterval() int {
if o == nil || o.BlockRestartInterval <= 0 {
return DefaultBlockRestartInterval
}
return o.BlockRestartInterval
}
func (o *Options) GetBlockSize() int {
if o == nil || o.BlockSize <= 0 {
return DefaultBlockSize
}
return o.BlockSize
}
func (o *Options) GetCompactionExpandLimit(level int) int {
factor := DefaultCompactionExpandLimitFactor
if o != nil && o.CompactionExpandLimitFactor > 0 {
factor = o.CompactionExpandLimitFactor
}
return o.GetCompactionTableSize(level+1) * factor
}
func (o *Options) GetCompactionGPOverlaps(level int) int {
factor := DefaultCompactionGPOverlapsFactor
if o != nil && o.CompactionGPOverlapsFactor > 0 {
factor = o.CompactionGPOverlapsFactor
}
return o.GetCompactionTableSize(level+2) * factor
}
func (o *Options) GetCompactionL0Trigger() int {
if o == nil || o.CompactionL0Trigger == 0 {
return DefaultCompactionL0Trigger
}
return o.CompactionL0Trigger
}
func (o *Options) GetCompactionSourceLimit(level int) int {
factor := DefaultCompactionSourceLimitFactor
if o != nil && o.CompactionSourceLimitFactor > 0 {
factor = o.CompactionSourceLimitFactor
}
return o.GetCompactionTableSize(level+1) * factor
}
func (o *Options) GetCompactionTableSize(level int) int {
var (
base = DefaultCompactionTableSize
mult float64
)
if o != nil {
if o.CompactionTableSize > 0 {
base = o.CompactionTableSize
}
if level < len(o.CompactionTableSizeMultiplierPerLevel) && o.CompactionTableSizeMultiplierPerLevel[level] > 0 {
mult = o.CompactionTableSizeMultiplierPerLevel[level]
} else if o.CompactionTableSizeMultiplier > 0 {
mult = math.Pow(o.CompactionTableSizeMultiplier, float64(level))
}
}
if mult == 0 {
mult = math.Pow(DefaultCompactionTableSizeMultiplier, float64(level))
}
return int(float64(base) * mult)
}
func (o *Options) GetCompactionTotalSize(level int) int64 {
var (
base = DefaultCompactionTotalSize
mult float64
)
if o != nil {
if o.CompactionTotalSize > 0 {
base = o.CompactionTotalSize
}
if level < len(o.CompactionTotalSizeMultiplierPerLevel) && o.CompactionTotalSizeMultiplierPerLevel[level] > 0 {
mult = o.CompactionTotalSizeMultiplierPerLevel[level]
} else if o.CompactionTotalSizeMultiplier > 0 {
mult = math.Pow(o.CompactionTotalSizeMultiplier, float64(level))
}
}
if mult == 0 {
mult = math.Pow(DefaultCompactionTotalSizeMultiplier, float64(level))
}
return int64(float64(base) * mult)
}
func (o *Options) GetComparer() comparer.Comparer {
if o == nil || o.Comparer == nil {
return comparer.DefaultComparer
}
return o.Comparer
}
func (o *Options) GetCompression() Compression {
if o == nil || o.Compression <= DefaultCompression || o.Compression >= nCompression {
return DefaultCompressionType
}
return o.Compression
}
func (o *Options) GetDisableBufferPool() bool {
if o == nil {
return false
}
return o.DisableBufferPool
}
func (o *Options) GetDisableBlockCache() bool {
if o == nil {
return false
}
return o.DisableBlockCache
}
func (o *Options) GetDisableCompactionBackoff() bool {
if o == nil {
return false
}
return o.DisableCompactionBackoff
}
func (o *Options) GetDisableLargeBatchTransaction() bool {
if o == nil {
return false
}
return o.DisableLargeBatchTransaction
}
func (o *Options) GetErrorIfExist() bool {
if o == nil {
return false
}
return o.ErrorIfExist
}
func (o *Options) GetErrorIfMissing() bool {
if o == nil {
return false
}
return o.ErrorIfMissing
}
func (o *Options) GetFilter() filter.Filter {
if o == nil {
return nil
}
return o.Filter
}
func (o *Options) GetIteratorSamplingRate() int {
if o == nil || o.IteratorSamplingRate <= 0 {
return DefaultIteratorSamplingRate
}
return o.IteratorSamplingRate
}
func (o *Options) GetNoSync() bool {
if o == nil {
return false
}
return o.NoSync
}
func (o *Options) GetOpenFilesCacher() Cacher {
if o == nil || o.OpenFilesCacher == nil {
return DefaultOpenFilesCacher
}
if o.OpenFilesCacher == NoCacher {
return nil
}
return o.OpenFilesCacher
}
func (o *Options) GetOpenFilesCacheCapacity() int {
if o == nil || o.OpenFilesCacheCapacity == 0 {
return DefaultOpenFilesCacheCapacity
} else if o.OpenFilesCacheCapacity < 0 {
return 0
}
return o.OpenFilesCacheCapacity
}
func (o *Options) GetReadOnly() bool {
if o == nil {
return false
}
return o.ReadOnly
}
func (o *Options) GetStrict(strict Strict) bool {
if o == nil || o.Strict == 0 {
return DefaultStrict&strict != 0
}
return o.Strict&strict != 0
}
func (o *Options) GetWriteBuffer() int {
if o == nil || o.WriteBuffer <= 0 {
return DefaultWriteBuffer
}
return o.WriteBuffer
}
func (o *Options) GetWriteL0PauseTrigger() int {
if o == nil || o.WriteL0PauseTrigger == 0 {
return DefaultWriteL0PauseTrigger
}
return o.WriteL0PauseTrigger
}
func (o *Options) GetWriteL0SlowdownTrigger() int {
if o == nil || o.WriteL0SlowdownTrigger == 0 {
return DefaultWriteL0SlowdownTrigger
}
return o.WriteL0SlowdownTrigger
}
// ReadOptions holds the optional parameters for 'read operation'. The
// 'read operation' includes Get, Find and NewIterator.
type ReadOptions struct {
// DontFillCache defines whether block reads for this 'read operation'
// should be cached. If false then the block will be cached. This does
// not affects already cached block.
//
// The default value is false.
DontFillCache bool
// Strict will be OR'ed with global DB 'strict level' unless StrictOverride
// is present. Currently only StrictReader that has effect here.
Strict Strict
}
func (ro *ReadOptions) GetDontFillCache() bool {
if ro == nil {
return false
}
return ro.DontFillCache
}
func (ro *ReadOptions) GetStrict(strict Strict) bool {
if ro == nil {
return false
}
return ro.Strict&strict != 0
}
// WriteOptions holds the optional parameters for 'write operation'. The
// 'write operation' includes Write, Put and Delete.
type WriteOptions struct {
// Sync is whether to sync underlying writes from the OS buffer cache
// through to actual disk, if applicable. Setting Sync can result in
// slower writes.
//
// If false, and the machine crashes, then some recent writes may be lost.
// Note that if it is just the process that crashes (and the machine does
// not) then no writes will be lost.
//
// In other words, Sync being false has the same semantics as a write
// system call. Sync being true means write followed by fsync.
//
// The default value is false.
Sync bool
}
func (wo *WriteOptions) GetSync() bool {
if wo == nil {
return false
}
return wo.Sync
}
func GetStrict(o *Options, ro *ReadOptions, strict Strict) bool {
if ro.GetStrict(StrictOverride) {
return ro.GetStrict(strict)
} else {
return o.GetStrict(strict) || ro.GetStrict(strict)
}
}