/**
* Copyright 2017 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { CacheNode } from './CacheNode';
import { NamedNode, Node } from '../snap/Node';
import { Index } from '../snap/indexes/Index';
import { WriteTreeRef } from '../WriteTree';
import { ViewCache } from './ViewCache';
/**
* Since updates to filtered nodes might require nodes to be pulled in from "outside" the node, this interface
* can help to get complete children that can be pulled in.
* A class implementing this interface takes potentially multiple sources (e.g. user writes, server data from
* other views etc.) to try it's best to get a complete child that might be useful in pulling into the view.
*
* @interface
*/
export interface CompleteChildSource {
/**
* @param {!string} childKey
* @return {?Node}
*/
getCompleteChild(childKey: string): Node | null;
/**
* @param {!Index} index
* @param {!NamedNode} child
* @param {boolean} reverse
* @return {?NamedNode}
*/
getChildAfterChild(
index: Index,
child: NamedNode,
reverse: boolean
): NamedNode | null;
}
/**
* An implementation of CompleteChildSource that never returns any additional children
*
* @private
* @constructor
* @implements CompleteChildSource
*/
export class NoCompleteChildSource_ implements CompleteChildSource {
/**
* @inheritDoc
*/
getCompleteChild(childKey?: string): Node | null {
return null;
}
/**
* @inheritDoc
*/
getChildAfterChild(
index?: Index,
child?: NamedNode,
reverse?: boolean
): NamedNode | null {
return null;
}
}
/**
* Singleton instance.
* @const
* @type {!CompleteChildSource}
*/
export const NO_COMPLETE_CHILD_SOURCE = new NoCompleteChildSource_();
/**
* An implementation of CompleteChildSource that uses a WriteTree in addition to any other server data or
* old event caches available to calculate complete children.
*
*
* @implements CompleteChildSource
*/
export class WriteTreeCompleteChildSource implements CompleteChildSource {
/**
* @param {!WriteTreeRef} writes_
* @param {!ViewCache} viewCache_
* @param {?Node} optCompleteServerCache_
*/
constructor(
private writes_: WriteTreeRef,
private viewCache_: ViewCache,
private IoptCompleteServerCache_: Node | null = null
) {}
/**
* @inheritDoc
*/
getCompleteChild(childKey: string): Node | null {
const node = this.viewCache_.getEventCache();
if (node.isCompleteForChild(childKey)) {
return node.getNode().getImmediateChild(childKey);
} else {
const serverNode =
this.optCompleteServerCache_ != null
? new CacheNode(this.optCompleteServerCache_, true, false)
: this.viewCache_.getServerCache();
return this.writes_.calcCompleteChild(childKey, serverNode);
}
}
/**
* @inheritDoc
*/
getChildAfterChild(
index: Index,
child: NamedNode,
reverse: boolean
): NamedNode | null {
const completeServerData =
this.optCompleteServerCache_ != null
? this.optCompleteServerCache_
: this.viewCache_.getCompleteServerSnap();
const nodes = this.writes_.calcIndexedSlice(
completeServerData,
child,
1,
reverse,
index
);
if (nodes.length === 0) {
return null;
} else {
return nodes[0];
}
}
}
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