forked from ipfs/go-datastore
/
basic_ds.go
189 lines (155 loc) · 4.18 KB
/
basic_ds.go
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package datastore
import (
"io"
"log"
dsq "github.com/ipfs/go-datastore/query"
)
// Here are some basic datastore implementations.
type keyMap map[Key]interface{}
// MapDatastore uses a standard Go map for internal storage.
type MapDatastore struct {
values keyMap
}
// NewMapDatastore constructs a MapDatastore
func NewMapDatastore() (d *MapDatastore) {
return &MapDatastore{
values: keyMap{},
}
}
// Put implements Datastore.Put
func (d *MapDatastore) Put(key Key, value interface{}) (err error) {
d.values[key] = value
return nil
}
// Get implements Datastore.Get
func (d *MapDatastore) Get(key Key) (value interface{}, err error) {
val, found := d.values[key]
if !found {
return nil, ErrNotFound
}
return val, nil
}
// Has implements Datastore.Has
func (d *MapDatastore) Has(key Key) (exists bool, err error) {
_, found := d.values[key]
return found, nil
}
// Delete implements Datastore.Delete
func (d *MapDatastore) Delete(key Key) (err error) {
if _, found := d.values[key]; !found {
return ErrNotFound
}
delete(d.values, key)
return nil
}
// Query implements Datastore.Query
func (d *MapDatastore) Query(q dsq.Query) (dsq.Results, error) {
re := make([]dsq.Entry, 0, len(d.values))
for k, v := range d.values {
re = append(re, dsq.Entry{Key: k.String(), Value: v})
}
r := dsq.ResultsWithEntries(q, re)
r = dsq.NaiveQueryApply(q, r)
return r, nil
}
func (d *MapDatastore) Batch() (Batch, error) {
return NewBasicBatch(d), nil
}
func (d *MapDatastore) Close() error {
return nil
}
// NullDatastore stores nothing, but conforms to the API.
// Useful to test with.
type NullDatastore struct {
}
// NewNullDatastore constructs a null datastoe
func NewNullDatastore() *NullDatastore {
return &NullDatastore{}
}
// Put implements Datastore.Put
func (d *NullDatastore) Put(key Key, value interface{}) (err error) {
return nil
}
// Get implements Datastore.Get
func (d *NullDatastore) Get(key Key) (value interface{}, err error) {
return nil, nil
}
// Has implements Datastore.Has
func (d *NullDatastore) Has(key Key) (exists bool, err error) {
return false, nil
}
// Delete implements Datastore.Delete
func (d *NullDatastore) Delete(key Key) (err error) {
return nil
}
// Query implements Datastore.Query
func (d *NullDatastore) Query(q dsq.Query) (dsq.Results, error) {
return dsq.ResultsWithEntries(q, nil), nil
}
func (d *NullDatastore) Batch() (Batch, error) {
return NewBasicBatch(d), nil
}
func (d *NullDatastore) Close() error {
return nil
}
// LogDatastore logs all accesses through the datastore.
type LogDatastore struct {
Name string
child Datastore
}
// Shim is a datastore which has a child.
type Shim interface {
Datastore
Children() []Datastore
}
// NewLogDatastore constructs a log datastore.
func NewLogDatastore(ds Datastore, name string) *LogDatastore {
if len(name) < 1 {
name = "LogDatastore"
}
return &LogDatastore{Name: name, child: ds}
}
// Children implements Shim
func (d *LogDatastore) Children() []Datastore {
return []Datastore{d.child}
}
// Put implements Datastore.Put
func (d *LogDatastore) Put(key Key, value interface{}) (err error) {
log.Printf("%s: Put %s\n", d.Name, key)
// log.Printf("%s: Put %s ```%s```", d.Name, key, value)
return d.child.Put(key, value)
}
// Get implements Datastore.Get
func (d *LogDatastore) Get(key Key) (value interface{}, err error) {
log.Printf("%s: Get %s\n", d.Name, key)
return d.child.Get(key)
}
// Has implements Datastore.Has
func (d *LogDatastore) Has(key Key) (exists bool, err error) {
log.Printf("%s: Has %s\n", d.Name, key)
return d.child.Has(key)
}
// Delete implements Datastore.Delete
func (d *LogDatastore) Delete(key Key) (err error) {
log.Printf("%s: Delete %s\n", d.Name, key)
return d.child.Delete(key)
}
// Query implements Datastore.Query
func (d *LogDatastore) Query(q dsq.Query) (dsq.Results, error) {
log.Printf("%s: Query\n", d.Name)
return d.child.Query(q)
}
func (d *LogDatastore) Batch() (Batch, error) {
log.Printf("%s: Batch\n", d.Name)
if bds, ok := d.child.(Batching); ok {
return bds.Batch()
}
return nil, ErrBatchUnsupported
}
func (d *LogDatastore) Close() error {
log.Printf("%s: Close\n", d.Name)
if cds, ok := d.child.(io.Closer); ok {
return cds.Close()
}
return nil
}