Golang Context.ConstructKey方法代码示例

// Delete removes a value with given key.
func (db *LevelDB) Delete(ctx storage.Context, tk storage.TKey) error {
	if db == nil {
		return fmt.Errorf("Can't call Delete on nil LevelDB")
	}
	if ctx == nil {
		return fmt.Errorf("Received nil context in Delete()")
	}
	wo := db.options.WriteOptions

	var err error
	key := ctx.ConstructKey(tk)
	if !ctx.Versioned() {
		dvid.StartCgo()
		err = db.ldb.Delete(wo, key)
		dvid.StopCgo()
	} else {
		vctx, ok := ctx.(storage.VersionedCtx)
		if !ok {
			return fmt.Errorf("Non-versioned context that says it's versioned received in Delete(): %v", ctx)
		}
		tombstoneKey := vctx.TombstoneKey(tk)
		batch := db.NewBatch(vctx).(*goBatch)
		batch.WriteBatch.Delete(key)
		batch.WriteBatch.Put(tombstoneKey, dvid.EmptyValue())
		if err = batch.Commit(); err != nil {
			dvid.Criticalf("Error on batch commit of Delete: %v\n", err)
			err = fmt.Errorf("Error on batch commit of Delete: %v", err)
		}
	}

	return err
}

// Put writes a value with given key.
func (db *LevelDB) Put(ctx storage.Context, tk storage.TKey, v []byte) error {
	if ctx == nil {
		return fmt.Errorf("Received nil context in Put()")
	}
	wo := db.options.WriteOptions

	var err error
	key := ctx.ConstructKey(tk)
	if !ctx.Versioned() {
		dvid.StartCgo()
		err = db.ldb.Put(wo, key, v)
		dvid.StopCgo()
	} else {
		vctx, ok := ctx.(storage.VersionedCtx)
		if !ok {
			return fmt.Errorf("Non-versioned context that says it's versioned received in Put(): %v", ctx)
		}
		tombstoneKey := vctx.TombstoneKey(tk)
		batch := db.NewBatch(vctx).(*goBatch)
		batch.WriteBatch.Delete(tombstoneKey)
		batch.WriteBatch.Put(key, v)
		if err = batch.Commit(); err != nil {
			batch.Close()
			err = fmt.Errorf("Error on PUT: %v\n", err)
		}
	}

	storage.StoreKeyBytesWritten <- len(key)
	storage.StoreValueBytesWritten <- len(v)
	return err
}

// Delete removes a value with given key.
func (db *KVAutobus) Delete(ctx storage.Context, tk storage.TKey) error {
	if ctx == nil {
		return fmt.Errorf("Received nil context in Delete()")
	}
	key := ctx.ConstructKey(tk)
	return db.RawDelete(key)
}

// Get returns a value given a key.
func (db *LevelDB) Get(ctx storage.Context, tk storage.TKey) ([]byte, error) {
	if ctx == nil {
		return nil, fmt.Errorf("Received nil context in Get()")
	}
	if ctx.Versioned() {
		vctx, ok := ctx.(storage.VersionedCtx)
		if !ok {
			return nil, fmt.Errorf("Bad Get(): context is versioned but doesn't fulfill interface: %v", ctx)
		}

		// Get all versions of this key and return the most recent
		// log.Printf("  basholeveldb versioned get of key %v\n", k)
		values, err := db.getSingleKeyVersions(vctx, tk)
		// log.Printf("            got back %v\n", values)
		if err != nil {
			return nil, err
		}
		kv, err := vctx.VersionedKeyValue(values)
		// log.Printf("  after deversioning: %v\n", kv)
		if kv != nil {
			return kv.V, err
		}
		return nil, err
	} else {
		key := ctx.ConstructKey(tk)
		ro := db.options.ReadOptions
		// log.Printf("  basholeveldb unversioned get of key %v\n", key)
		dvid.StartCgo()
		v, err := db.ldb.Get(ro, key)
		dvid.StopCgo()
		storage.StoreValueBytesRead <- len(v)
		return v, err
	}
}

// Get returns a value given a key.
func (db *KVAutobus) Get(ctx storage.Context, tk storage.TKey) ([]byte, error) {
	if ctx == nil {
		return nil, fmt.Errorf("Received nil context in Get()")
	}
	if ctx.Versioned() {
		vctx, ok := ctx.(storage.VersionedCtx)
		if !ok {
			return nil, fmt.Errorf("Bad Get(): context is versioned but doesn't fulfill interface: %v", ctx)
		}

		// Get all versions of this key and return the most recent
		// log.Printf("  kvautobus versioned get of key %v\n", k)
		key := ctx.ConstructKey(tk)
		dvid.Infof("   Get on key: %s\n", hex.EncodeToString(key))
		values, err := db.getSingleKeyVersions(vctx, tk)
		// log.Printf("            got back %v\n", values)
		if err != nil {
			return nil, err
		}
		kv, err := vctx.VersionedKeyValue(values)
		// log.Printf("  after deversioning: %v\n", kv)
		if kv != nil {
			return kv.V, err
		}
		return nil, err
	} else {
		key := ctx.ConstructKey(tk)
		// log.Printf("  kvautobus unversioned get of key %v\n", key)
		v, err := db.RawGet(key)
		storage.StoreValueBytesRead <- len(v)
		return v, err
	}
}

// GetTileKey returns the internal key as a hexadecimal string
func (d *Data) GetTileKey(ctx storage.Context, w http.ResponseWriter, r *http.Request, parts []string) (string, error) {
	req, err := d.ParseTileReq(r, parts)
	if err != nil {
		return "", err
	}
	tk := NewTKeyByTileReq(req)
	key := ctx.ConstructKey(tk)
	return fmt.Sprintf("%x", key), nil
}

// PutRange puts type key-value pairs that have been sorted in sequential key order.
func (db *KVAutobus) PutRange(ctx storage.Context, tkvs []storage.TKeyValue) error {
	if ctx == nil {
		return fmt.Errorf("Received nil context in PutRange()")
	}
	kvs := make([]storage.KeyValue, len(tkvs))
	for i, tkv := range tkvs {
		kvs[i] = storage.KeyValue{ctx.ConstructKey(tkv.K), tkv.V}
	}
	return db.putRange(kvs)
}

// DeleteRange removes all key-value pairs with keys in the given range.  Versioned
// contexts cannot use immutable stores to delete ranges.
func (db *KVAutobus) DeleteRange(ctx storage.Context, kStart, kEnd storage.TKey) error {
	if ctx == nil {
		return fmt.Errorf("Received nil context in DeleteRange()")
	}
	if ctx.Versioned() {
		return fmt.Errorf("DeleteRange() not supported for versioned contexts in immutable store")
	}
	keyBeg := ctx.ConstructKey(kStart)
	keyEnd := ctx.ConstructKey(kEnd)
	return db.deleteRange(keyBeg, keyEnd)
}

// Put writes a value with given key.  Since KVAutobus is immutable, we do not
// have to worry about a PUT on a previously deleted key.
func (db *KVAutobus) Put(ctx storage.Context, tk storage.TKey, v []byte) error {
	if ctx == nil {
		return fmt.Errorf("Received nil context in Put()")
	}

	key := ctx.ConstructKey(tk)
	err := db.RawPut(key, v)
	if err != nil {
		return err
	}
	return nil
}

// unversionedRange sends a range of key-value pairs down a channel.
func (db *LevelDB) unversionedRange(ctx storage.Context, begTKey, endTKey storage.TKey, ch chan errorableKV, done <-chan struct{}, keysOnly bool) {
	dvid.StartCgo()
	ro := levigo.NewReadOptions()
	it := db.ldb.NewIterator(ro)
	defer func() {
		it.Close()
		dvid.StopCgo()
	}()

	// Apply context if applicable
	begKey := ctx.ConstructKey(begTKey)
	endKey := ctx.ConstructKey(endTKey)

	// fmt.Printf("unversionedRange():\n")
	// fmt.Printf("    index beg: %v\n", kStart)
	// fmt.Printf("    index end: %v\n", kEnd)
	// fmt.Printf("    key start: %v\n", keyBeg)
	// fmt.Printf("      key end: %v\n", keyEnd)

	var itValue []byte
	it.Seek(begKey)
	for {
		if it.Valid() {
			// fmt.Printf("unversioned found key %v, %d bytes value\n", it.Key(), len(it.Value()))
			if !keysOnly {
				itValue = it.Value()
				storage.StoreValueBytesRead <- len(itValue)
			}
			itKey := it.Key()
			storage.StoreKeyBytesRead <- len(itKey)
			// Did we pass the final key?
			if bytes.Compare(itKey, endKey) > 0 {
				break
			}
			select {
			case <-done:
				ch <- errorableKV{nil, nil}
				return
			case ch <- errorableKV{&storage.KeyValue{K: itKey, V: itValue}, nil}:
				it.Next()
			}
		} else {
			break
		}
	}
	if err := it.GetError(); err != nil {
		ch <- errorableKV{nil, err}
	} else {
		ch <- errorableKV{nil, nil}
	}
	return
}

// unversionedRange sends a range of key-value pairs down a channel.
func (db *KVAutobus) unversionedRange(ctx storage.Context, kStart, kEnd storage.TKey, ch chan errorableKV, keysOnly bool) {
	keyBeg := ctx.ConstructKey(kStart)
	keyEnd := ctx.ConstructKey(kEnd)

	kvs, err := db.getRange(ctx, keyBeg, keyEnd)
	if err != nil {
		ch <- errorableKV{nil, err}
	}
	for _, kv := range kvs {
		ch <- errorableKV{kv, nil}
	}
	ch <- errorableKV{nil, nil}
}

// Put writes a value with given key.  Since KVAutobus is immutable, we do not
// have to worry about a PUT on a previously deleted key.
func (db *KVAutobus) Put(ctx storage.Context, tk storage.TKey, v []byte) error {
	if ctx == nil {
		return fmt.Errorf("Received nil context in Put()")
	}

	key := ctx.ConstructKey(tk)
	err := db.RawPut(key, v)
	if err != nil {
		return err
	}
	storage.StoreKeyBytesWritten <- len(key)
	storage.StoreValueBytesWritten <- len(v)
	return nil
}

// unversionedRange sends a range of key-value pairs down a channel.
func (db *KVAutobus) unversionedRange(ctx storage.Context, kStart, kEnd storage.TKey, ch chan errorableKV, keysOnly bool) {
	keyBeg := ctx.ConstructKey(kStart)
	keyEnd := ctx.ConstructKey(kEnd)

	kvs, err := db.getRange(keyBeg, keyEnd)
	if err != nil {
		ch <- errorableKV{nil, err}
	}
	for _, kv := range kvs {
		if !keysOnly {
			storage.StoreValueBytesRead <- len(kv.V)
		}
		storage.StoreKeyBytesRead <- len(kv.K)
		ch <- errorableKV{kv, nil}
	}
	ch <- errorableKV{nil, nil}
	return
}