blockstore

Documentation

Overview

package blockstore implements a thin wrapper over a datastore, giving a clean interface for Getting and Putting block objects.

Index

• Variables
• func NewBlockstore(d ds.Batching) *blockstore
• type Blockstore
• type CacheOpts
  • func DefaultCacheOpts() CacheOpts
• type GCBlockstore
  • func CachedBlockstore(bs GCBlockstore, ctx context.Context, opts CacheOpts) (cbs GCBlockstore, err error)
• type Unlocker

Variables

var BlockPrefix = ds.NewKey("blocks")

BlockPrefix namespaces blockstore datastores

var ErrHashMismatch = errors.New("block in storage has different hash than requested")

var ErrNotFound = errors.New("blockstore: block not found")

var ValueTypeMismatch = errors.New("the retrieved value is not a Block")

Functions

func NewBlockstore

func NewBlockstore(d ds.Batching) *blockstore

Types

type Blockstore

type Blockstore interface {
	DeleteBlock(key.Key) error
	Has(key.Key) (bool, error)
	Get(key.Key) (blocks.Block, error)
	Put(blocks.Block) error
	PutMany([]blocks.Block) error

	AllKeysChan(ctx context.Context) (<-chan key.Key, error)
}

Blockstore wraps a Datastore

type CacheOpts

type CacheOpts struct {
	HasBloomFilterSize   int // 1 bit
	HasBloomFilterHashes int // No size, 7 is usually best, consult bloom papers
	HasARCCacheSize      int // 32 bytes
}

Next to each option is it aproximate memory usage per unit

func DefaultCacheOpts

func DefaultCacheOpts() CacheOpts

type GCBlockstore

type GCBlockstore interface {
	Blockstore

	// GCLock locks the blockstore for garbage collection. No operations
	// that expect to finish with a pin should ocurr simultaneously.
	// Reading during GC is safe, and requires no lock.
	GCLock() Unlocker

	// PinLock locks the blockstore for sequences of puts expected to finish
	// with a pin (before GC). Multiple put->pin sequences can write through
	// at the same time, but no GC should not happen simulatenously.
	// Reading during Pinning is safe, and requires no lock.
	PinLock() Unlocker

	// GcRequested returns true if GCLock has been called and is waiting to
	// take the lock
	GCRequested() bool
}

func CachedBlockstore

func CachedBlockstore(bs GCBlockstore,
	ctx context.Context, opts CacheOpts) (cbs GCBlockstore, err error)

type Unlocker

type Unlocker interface {
	Unlock()
}