Add 'user friendly' datastore API.

service/rawdatastore/interface.go

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package rawdatastore
-
-import (
-        "fmt"
-
-        "golang.org/x/net/context"
-)
-
-// Key is the equivalent of *datastore.Key from the original SDK, except that
-// it can have multiple implementations. See helper.Key* methods for missing
-// methods like KeyIncomplete (and some new ones like KeyValid).
-type Key interface {
-        Kind() string
-        StringID() string
-        IntID() int64
-        Parent() Key
-        AppID() string
-        Namespace() string
-
-        String() string
-}
-
-// KeyTok is a single token from a multi-part Key.
-type KeyTok struct {
-        Kind     string
-        IntID    int64
-        StringID string
-}
-
-// Cursor wraps datastore.Cursor.
-type Cursor interface {
-        fmt.Stringer
-}
-
-// Query wraps datastore.Query.
-type Query interface {
-        Ancestor(ancestor Key) Query
-        Distinct() Query
-        End(c Cursor) Query
-        EventualConsistency() Query
-        Filter(filterStr string, value interface{}) Query
-        KeysOnly() Query
-        Limit(limit int) Query
-        Offset(offset int) Query
-        Order(fieldName string) Query
-        Project(fieldNames ...string) Query
-        Start(c Cursor) Query
-}
-
-// RunCB is the callback signature provided to Interface.Run
-//
-//   - key is the Key of the entity
-//   - val is the data of the entity (or nil, if the query was keys-only)
-//   - getCursor can be invoked to obtain the current cursor.
-//
-// Return true to continue iterating through the query results, or false to stop.
-type RunCB func(key Key, val PropertyMap, getCursor func() (Cursor, error)) bool
-
-// GetMultiCB is the callback signature provided to Interface.GetMulti
-//
-//   - val is the data of the entity
-//     * It may be nil if some of the keys to the GetMulti were bad, since all
-//       keys are validated before the RPC occurs!
-//   - err is an error associated with this entity (e.g. ErrNoSuchEntity).
-type GetMultiCB func(val PropertyMap, err error)
-
-// PutMultiCB is the callback signature provided to Interface.PutMulti
-//
-//   - key is the new key for the entity (if the original was incomplete)
-//     * It may be nil if some of the keys/vals to the PutMulti were bad, since
-//       all keys are validated before the RPC occurs!
-//   - err is an error associated with putting this entity.
-type PutMultiCB func(key Key, err error)
-
-// DeleteMultiCB is the callback signature provided to Interface.DeleteMulti
-//
-//   - err is an error associated with deleting this entity.
-type DeleteMultiCB func(err error)
-
-// Interface implements the datastore functionality without any of the fancy
-// reflection stuff. This is so that Filters can avoid doing lots of redundant
-// reflection work. See datastore.Interface for a more user-friendly interface.
-type Interface interface {
-        NewKey(kind, stringID string, intID int64, parent Key) Key
-        DecodeKey(encoded string) (Key, error)
-        NewQuery(kind string) Query
-
-        RunInTransaction(f func(c context.Context) error, opts *TransactionOptions) error
-
-        // Run executes the given query, and calls `cb` for each successfully item.
-        Run(q Query, cb RunCB) error
-
-        // GetMulti retrieves items from the datastore.
-        //
-        // Callback execues once per key, in the order of keys. Callback may not
-        // execute at all if there's a server error. If callback is nil, this
-        // method does nothing.
-        //
-        // NOTE: Implementations and filters are guaranteed that keys are all Valid
-        // and Complete, and in the correct namespace.
-        GetMulti(keys []Key, cb GetMultiCB) error
-
-        // PutMulti writes items to the datastore.
-        //
-        // Callback execues once per item, in the order of itemss. Callback may not
-        // execute at all if there's a server error.
-        //
-        // NOTE: Implementations and filters are guaranteed that len(keys) ==
-        // len(vals), that keys are all Valid, and in the correct namespace.
-        // Additionally, vals are guaranteed to be PropertyMaps already. Callback
-        // may be nil.
-        PutMulti(keys []Key, vals []PropertyLoadSaver, cb PutMultiCB) error
-
-        // DeleteMulti removes items from the datastore.
-        //
-        // Callback execues once per key, in the order of keys. Callback may not
-        // execute at all if there's a server error.
-        //
-        // NOTE: Implementations and filters are guaranteed that keys are all Valid
-        // and Complete, and in the correct namespace, and are not 'special'.
-        // Callback may be nil.
-        DeleteMulti(keys []Key, cb DeleteMultiCB) error
-}