types

Documentation

Index

• type Batch
• type DB
• type DataTree
• type Entry
• type EntryHandler
• type EntryX
• type HotEntry
• type IndexTree
• type Iterator
• type IteratorUI64
• type KeyAndPos
• type MetaDB
• type OperationOnEntry
• type SetDeleter

Types

type Batch

type Batch interface {
	SetDeleter
	Write()
	WriteSync()
	Close()
}

Batch Close must be called when the program no longer needs the object.

type DB

type DB interface {

	// Get returns nil iff key doesn't exist.
	// A nil key is interpreted as an empty byteslice.
	// CONTRACT: key, value readonly []byte
	Get([]byte) []byte

	// Has checks if a key exists.
	// A nil key is interpreted as an empty byteslice.
	// CONTRACT: key, value readonly []byte
	Has(key []byte) bool

	// Set sets the key.
	// A nil key is interpreted as an empty byteslice.
	// CONTRACT: key, value readonly []byte
	Set([]byte, []byte)
	SetSync([]byte, []byte)

	// Delete deletes the key.
	// A nil key is interpreted as an empty byteslice.
	// CONTRACT: key readonly []byte
	Delete([]byte)
	DeleteSync([]byte)

	// Iterate over a domain of keys in ascending order. End is exclusive.
	// Start must be less than end, or the Iterator is invalid.
	// A nil start is interpreted as an empty byteslice.
	// If end is nil, iterates up to the last item (inclusive).
	// CONTRACT: No writes may happen within a domain while an iterator exists over it.
	// CONTRACT: start, end readonly []byte
	Iterator(start, end []byte) Iterator

	// Iterate over a domain of keys in descending order. End is exclusive.
	// Start must be less than end, or the Iterator is invalid.
	// If start is nil, iterates up to the first/least item (inclusive).
	// If end is nil, iterates from the last/greatest item (inclusive).
	// CONTRACT: No writes may happen within a domain while an iterator exists over it.
	// CONTRACT: start, end readonly []byte
	ReverseIterator(start, end []byte) Iterator

	// Closes the connection.
	Close()

	// Creates a batch for atomic updates.
	NewBatch() Batch

	// For debugging
	Print()

	// Stats returns a map of property values for all keys and the size of the cache.
	Stats() map[string]string
}

DBs are goroutine safe.

type DataTree

type DataTree interface {
	DeactiviateEntry(sn int64) int
	AppendEntry(entry *Entry) int64
	AppendEntryRawBytes(entryBz []byte, sn int64) int64
	ReadEntry(pos int64) *Entry
	GetActiveBit(sn int64) bool
	EvictTwig(twigID int64)
	GetActiveEntriesInTwig(twigID int64) chan []byte
	ScanEntries(oldestActiveTwigID int64, outChan chan EntryX)
	ScanEntriesLite(oldestActiveTwigID int64, outChan chan KeyAndPos)
	TwigCanBePruned(twigID int64) bool
	PruneTwigs(startID, endID int64) []byte
	GetFileSizes() (int64, int64)
	EndBlock() []byte
	Flush()
	Close()
}

type Entry

type Entry struct {
	Key        []byte
	Value      []byte
	NextKey    []byte
	Height     int64
	LastHeight int64
	SerialNum  int64
}

type EntryHandler

type EntryHandler func(pos int64, entry *Entry, deactivedSNList []int64)

type EntryX

type EntryX struct {
	Entry           *Entry
	Pos             int64
	DeactivedSNList []int64
}

type HotEntry

type HotEntry struct {
	EntryPtr        *Entry
	Operation       OperationOnEntry
	IsModified      bool
	IsTouchedByNext bool
}

type IndexTree

type IndexTree interface {
	Init(repFn func([]byte)) error
	ActiveCount() int
	BeginWrite(height int64)
	EndWrite()
	Iterator(start, end []byte) IteratorUI64
	ReverseIterator(start, end []byte) IteratorUI64
	Get(k []byte) (uint64, bool)
	GetAtHeight(k []byte, height uint64) (uint64, bool)
	Set(k []byte, v uint64)
	Delete(k []byte)
	Close()
}

type Iterator

type Iterator interface {

	// The start & end (exclusive) limits to iterate over.
	// If end < start, then the Iterator goes in reverse order.
	//
	// A domain of ([]byte{12, 13}, []byte{12, 14}) will iterate
	// over anything with the prefix []byte{12, 13}.
	//
	// The smallest key is the empty byte array []byte{} - see BeginningKey().
	// The largest key is the nil byte array []byte(nil) - see EndingKey().
	// CONTRACT: start, end readonly []byte
	Domain() (start []byte, end []byte)

	// Valid returns whether the current position is valid.
	// Once invalid, an Iterator is forever invalid.
	Valid() bool

	// Next moves the iterator to the next sequential key in the database, as
	// defined by order of iteration.
	//
	// If Valid returns false, this method will panic.
	Next()

	// Key returns the key of the cursor.
	// If Valid returns false, this method will panic.
	// CONTRACT: key readonly []byte
	Key() (key []byte)

	// Value returns the value of the cursor.
	// If Valid returns false, this method will panic.
	// CONTRACT: value readonly []byte
	Value() (value []byte)

	// Close releases the Iterator.
	Close()
}

Usage:

var itr Iterator = ... defer itr.Close()

for ; itr.Valid(); itr.Next() {
	k, v := itr.Key(); itr.Value()
	// ...
}

type IteratorUI64

type IteratorUI64 interface {
	Domain() (start []byte, end []byte)
	Valid() bool
	Next()
	Key() []byte
	Value() uint64
	Close()
}

type KeyAndPos

type KeyAndPos struct {
	Key []byte
	Pos int64
}

type MetaDB

type MetaDB interface {
	Commit()
	ReloadFromKVDB()
	PrintInfo()

	SetCurrHeight(h int64)
	GetCurrHeight() int64

	SetTwigMtFileSize(size int64)
	GetTwigMtFileSize() int64

	SetEntryFileSize(size int64)
	GetEntryFileSize() int64

	GetTwigHeight(twigID int64) int64
	DeleteTwigHeight(twigID int64)

	SetLastPrunedTwig(twigID int64)
	GetLastPrunedTwig() int64

	GetEdgeNodes() []byte
	SetEdgeNodes(bz []byte)

	// MaxSerialNum is the maximum serial num among all the entries
	GetMaxSerialNum() int64
	IncrMaxSerialNum() // It should call setTwigHeight(twigID int64, height int64)

	// the ID of the oldest active twig, increased by ReapOldestActiveTwig
	GetOldestActiveTwigID() int64
	IncrOldestActiveTwigID()

	GetIsRunning() bool
	SetIsRunning(isRunning bool)

	Init()
	Close()
}

type OperationOnEntry

type OperationOnEntry int32

const (
	OpNone OperationOnEntry = iota
	OpDelete
	OpInsertOrChange
)

type SetDeleter

type SetDeleter interface {
	Set(key, value []byte) // CONTRACT: key, value readonly []byte
	Delete(key []byte)     // CONTRACT: key readonly []byte
}