levelup

README

levelup

This package implements a few types and interfaces to be used by the actual "down" libraries, which will implement the core functionality of each database.

Some of the "down" libraries implementing the "up" interface:

• goleveldown
• rocksdown
• levelup-js

Any similarity with the Node.js LevelUP is mere coincidence.

some things:

• When the value for some key is "" or blank or not found, NotFound will be returned.
• RangeOpts treats go zero values as if you didn't pass anything, so Limit: 0 is the same as no limit, Start: "" is the same as no start etc.
• In RangeOpts Start is inclusive, End is non-inclusive.
• All keys and values are []byte, if you want to use strings, see github.com/fiatjaf/levelup/stringlevelup.

---

traffic analytics for this repo:

Documentation

Index

• Constants
• Variables
• type DB
• type Error
  • func (e Error) Error() string
• type Operation
  • func Del(key []byte) Operation
  • func Put(key, value []byte) Operation
• type RangeOpts
  • func (ro *RangeOpts) FillDefaults()
• type ReadIterator

Constants

const (
	NotFound = Error("levelup: not found")
)

Variables

var (
	DefaultRangeLimit = 9999999
	DefaultRangeEnd   = []byte{0xff, 0xff, 0xff, 0xff, 0xff}
)

var BatchDel = Del

var BatchPut = Put

Types

type DB

type DB interface {
	Close()
	Erase()
	Put([]byte, []byte) error
	Get([]byte) ([]byte, error)
	Del([]byte) error
	Batch([]Operation) error
	ReadRange(*RangeOpts) ReadIterator
}

type Error

type Error string

func (Error) Error

func (e Error) Error() string

type Operation

type Operation struct {
	Type  string
	Key   []byte
	Value []byte
}

func Del

func Del(key []byte) Operation

func Put

func Put(key, value []byte) Operation

type RangeOpts

type RangeOpts struct {
	Start   []byte // included, default []byte{}
	End     []byte // not included, default []byte{0xff, 0xff, 0xff, 0xff, 0xff}
	Reverse bool   // default false
	Limit   int    // default 9999999
}

func (*RangeOpts) FillDefaults

func (ro *RangeOpts) FillDefaults()

type ReadIterator

type ReadIterator interface {
	Valid() bool   // returns false when we have reached the end of the rows we asked for.
	Next()         // go to the next row.
	Key() []byte   // the key in the current row.
	Value() []byte // the value in the current row.
	Error() error  // if some error has happened this have it.
	Release()      // it may be necessary to call this after using, or defer it.
}