goleveldown

README

goleveldown

This package implements the levelup interface.

how to use

package main

import (
    "github.com/fiatjaf/goleveldown"
    "github.com/fiatjaf/levelup"
    "github.com/fiatjaf/levelup/stringlevelup"
)

func main() {
    bdb := goleveldown.NewDatabase("/tmp/leveldownexample")
    defer bdb.Erase()

    db := stringlevelup.StringDB(bdb)

    fmt.Println("setting key1 to x")
    db.Put("key1", "x")
    res, _ := db.Get("key1")
    fmt.Println("setting key2 to 2")
    fmt.Println("res at key2: ", res)
    db.Put("key2", "y")
    res, _ = db.Get("key2")
    fmt.Println("res at key2: ", res)
    fmt.Println("deleting key1")
    db.Del("key1")
    res, _ = db.Get("key1")
    fmt.Println("res at key1: ", res)

    fmt.Println("batch")
    db.Batch([]levelup.Operation{
        stringlevelup.Put("key2", "w"),
        stringlevelup.Put("key3", "z"),
        stringlevelup.Del("key1"),
        stringlevelup.Put("key1", "t"),
        stringlevelup.Put("key4", "m"),
        stringlevelup.Put("key5", "n"),
        stringlevelup.Del("key3"),
    })
    res, _ = db.Get("key1")
    fmt.Println("res at key1: ", res)
    res, _ = db.Get("key2")
    fmt.Println("res at key2: ", res)
    res, _ = db.Get("key3")
    fmt.Println("res at key3: ", res)

    fmt.Println("reading all")
    iter := db.ReadRange(nil)
    for ; iter.Valid(); iter.Next() {
        fmt.Println("row: ", iter.Key(), " ", iter.Value())
    }
    fmt.Println("iter error: ", iter.Error())
    iter.Release()
}

if you don't call stringlevelup.StringDB on the object returned by NewDatabase you still can use the same methods, only replacing all string arguments with []byte (returned values will also be bytes). I've just used the string approach here for readability, but it is slower.

Documentation

Index

• func NewDatabase(path string) levelup.DB
• type LevelDown
  • func (l LevelDown) Batch(ops []levelup.Operation) error
  • func (l LevelDown) Close()
  • func (l LevelDown) Del(key []byte) error
  • func (l LevelDown) Erase()
  • func (l LevelDown) Get(key []byte) ([]byte, error)
  • func (l LevelDown) Put(key, value []byte) error
  • func (l LevelDown) ReadRange(opts *levelup.RangeOpts) levelup.ReadIterator
• type ReadIterator
  • func (ri *ReadIterator) Error() error
  • func (ri *ReadIterator) Key() []byte
  • func (ri *ReadIterator) Next()
  • func (ri *ReadIterator) Release()
  • func (ri *ReadIterator) Valid() bool
  • func (ri *ReadIterator) Value() []byte

Functions

func NewDatabase

func NewDatabase(path string) levelup.DB

Types

type LevelDown

type LevelDown struct {
	// contains filtered or unexported fields
}

func (LevelDown) Batch

func (l LevelDown) Batch(ops []levelup.Operation) error

func (LevelDown) Close

func (l LevelDown) Close()

func (LevelDown) Del

func (l LevelDown) Del(key []byte) error

func (LevelDown) Erase

func (l LevelDown) Erase()

func (LevelDown) Get

func (l LevelDown) Get(key []byte) ([]byte, error)

func (LevelDown) Put

func (l LevelDown) Put(key, value []byte) error

func (LevelDown) ReadRange

func (l LevelDown) ReadRange(opts *levelup.RangeOpts) levelup.ReadIterator

type ReadIterator

type ReadIterator struct {
	// contains filtered or unexported fields
}

func (*ReadIterator) Error

func (ri *ReadIterator) Error() error

func (*ReadIterator) Key

func (ri *ReadIterator) Key() []byte

func (*ReadIterator) Next

func (ri *ReadIterator) Next()

func (*ReadIterator) Release

func (ri *ReadIterator) Release()

func (*ReadIterator) Valid

func (ri *ReadIterator) Valid() bool

func (*ReadIterator) Value

func (ri *ReadIterator) Value() []byte