98 lines
2.8 KiB
Go
98 lines
2.8 KiB
Go
// Copyright (C) 2014 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at http://mozilla.org/MPL/2.0/.
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package db
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import (
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"encoding/binary"
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"time"
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"github.com/syndtr/goleveldb/leveldb"
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)
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// NamespacedKV is a simple key-value store using a specific namespace within
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// a leveldb.
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type NamespacedKV struct {
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db *leveldb.DB
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prefix []byte
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}
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// NewNamespacedKV returns a new NamespacedKV that lives in the namespace
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// specified by the prefix.
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func NewNamespacedKV(db *leveldb.DB, prefix string) *NamespacedKV {
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return &NamespacedKV{
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db: db,
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prefix: []byte(prefix),
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}
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}
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// PutInt64 stores a new int64. Any existing value (even if of another type)
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// is overwritten.
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func (n *NamespacedKV) PutInt64(key string, val int64) {
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keyBs := append(n.prefix, []byte(key)...)
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var valBs [8]byte
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binary.BigEndian.PutUint64(valBs[:], uint64(val))
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n.db.Put(keyBs, valBs[:], nil)
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}
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// Int64 returns the stored value interpreted as an int64 and a boolean that
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// is false if no value was stored at the key.
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func (n *NamespacedKV) Int64(key string) (int64, bool) {
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keyBs := append(n.prefix, []byte(key)...)
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valBs, err := n.db.Get(keyBs, nil)
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if err != nil {
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return 0, false
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}
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val := binary.BigEndian.Uint64(valBs)
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return int64(val), true
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}
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// PutTime stores a new time.Time. Any existing value (even if of another
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// type) is overwritten.
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func (n *NamespacedKV) PutTime(key string, val time.Time) {
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keyBs := append(n.prefix, []byte(key)...)
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valBs, _ := val.MarshalBinary() // never returns an error
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n.db.Put(keyBs, valBs, nil)
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}
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// Time returns the stored value interpreted as a time.Time and a boolean
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// that is false if no value was stored at the key.
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func (n NamespacedKV) Time(key string) (time.Time, bool) {
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var t time.Time
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keyBs := append(n.prefix, []byte(key)...)
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valBs, err := n.db.Get(keyBs, nil)
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if err != nil {
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return t, false
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}
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err = t.UnmarshalBinary(valBs)
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return t, err == nil
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}
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// PutString stores a new string. Any existing value (even if of another type)
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// is overwritten.
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func (n *NamespacedKV) PutString(key, val string) {
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keyBs := append(n.prefix, []byte(key)...)
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n.db.Put(keyBs, []byte(val), nil)
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}
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// String returns the stored value interpreted as a string and a boolean that
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// is false if no value was stored at the key.
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func (n NamespacedKV) String(key string) (string, bool) {
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keyBs := append(n.prefix, []byte(key)...)
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valBs, err := n.db.Get(keyBs, nil)
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if err != nil {
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return "", false
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}
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return string(valBs), true
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}
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// Delete deletes the specified key. It is allowed to delete a nonexistent
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// key.
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func (n NamespacedKV) Delete(key string) {
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keyBs := append(n.prefix, []byte(key)...)
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n.db.Delete(keyBs, nil)
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}
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