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| /**
* 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 { IndexedFilter } from './filter/IndexedFilter';
import { ViewProcessor } from './ViewProcessor';
import { ChildrenNode } from '../snap/ChildrenNode';
import { CacheNode } from './CacheNode';
import { ViewCache } from './ViewCache';
import { EventGenerator } from './EventGenerator';
import { assert } from '@firebase/util';
import { Operation, OperationType } from '../operation/Operation';
import { Change } from './Change';
import { PRIORITY_INDEX } from '../snap/indexes/PriorityIndex';
import { Query } from '../../api/Query';
import { EventRegistration } from './EventRegistration';
import { Node } from '../snap/Node';
import { Path } from '../util/Path';
import { WriteTreeRef } from '../WriteTree';
import { CancelEvent, Event } from './Event';
/**
* A view represents a specific location and query that has 1 or more event registrations.
*
* It does several things:
* - Maintains the list of event registrations for this location/query.
* - Maintains a cache of the data visible for this location/query.
* - Applies new operations (via applyOperation), updates the cache, and based on the event
* registrations returns the set of events to be raised.
* @constructor
*/
export class View {
private processor_: ViewProcessor;
private viewCache_: ViewCache;
private eventRegistrations_: EventRegistration[] = [];
private eventGenerator_: EventGenerator;
/**
*
* @param {!Query} query_
* @param {!ViewCache} initialViewCache
*/
constructor(private query_: Query, initialViewCache: ViewCache) {
const params = this.query_.getQueryParams();
const indexFilter = new IndexedFilter(params.getIndex());
const filter = params.getNodeFilter();
/**
* @type {ViewProcessor}
* @private
*/
this.processor_ = new ViewProcessor(filter);
const initialServerCache = initialViewCache.getServerCache();
const initialEventCache = initialViewCache.getEventCache();
// Don't filter server node with other filter than index, wait for tagged listen
const serverSnap = indexFilter.updateFullNode(
ChildrenNode.EMPTY_NODE,
initialServerCache.getNode(),
null
);
const eventSnap = filter.updateFullNode(
ChildrenNode.EMPTY_NODE,
initialEventCache.getNode(),
null
);
const newServerCache = new CacheNode(
serverSnap,
initialServerCache.isFullyInitialized(),
indexFilter.filtersNodes()
);
const newEventCache = new CacheNode(
eventSnap,
initialEventCache.isFullyInitialized(),
filter.filtersNodes()
);
/**
* @type {!ViewCache}
* @private
*/
this.viewCache_ = new ViewCache(newEventCache, newServerCache);
/**
* @type {!EventGenerator}
* @private
*/
this.eventGenerator_ = new EventGenerator(this.query_);
}
/**
* @return {!Query}
*/
getQuery(): Query {
return this.query_;
}
/**
* @return {?Node}
*/
getServerCache(): Node | null {
return this.viewCache_.getServerCache().getNode();
}
/**
* @param {!Path} path
* @return {?Node}
*/
getCompleteServerCache(path: Path): Node | null {
const cache = this.viewCache_.getCompleteServerSnap();
if (cache) {
// If this isn't a "loadsAllData" view, then cache isn't actually a complete cache and
// we need to see if it contains the child we're interested in.
if (
this.query_.getQueryParams().loadsAllData() ||
(!path.isEmpty() && !cache.getImmediateChild(path.getFront()).isEmpty())
) {
return cache.getChild(path);
}
}
return null;
}
/**
* @return {boolean}
*/
isEmpty(): boolean {
return this.eventRegistrations_.length === 0;
}
/**
* @param {!EventRegistration} eventRegistration
*/
addEventRegistration(eventRegistration: EventRegistration) {
this.eventRegistrations_.push(eventRegistration);
}
/**
* @param {?EventRegistration} eventRegistration If null, remove all callbacks.
* @param {Error=} cancelError If a cancelError is provided, appropriate cancel events will be returned.
* @return {!Array.<!Event>} Cancel events, if cancelError was provided.
*/
removeEventRegistration(
eventRegistration: EventRegistration | null,
cancelError?: Error
): Event[] {
const cancelEvents: CancelEvent[] = [];
Iif (cancelError) {
assert(
eventRegistration == null,
'A cancel should cancel all event registrations.'
);
const path = this.query_.path;
this.eventRegistrations_.forEach(function(registration) {
cancelError /** @type {!Error} */ = cancelError;
const maybeEvent = registration.createCancelEvent(cancelError, path);
if (maybeEvent) {
cancelEvents.push(maybeEvent);
}
});
}
if (eventRegistration) {
let remaining = [];
for (let i = 0; i < this.eventRegistrations_.length; ++i) {
const existing = this.eventRegistrations_[i];
if (!existing.matches(eventRegistration)) {
remaining.push(existing);
} else if (eventRegistration.hasAnyCallback()) {
// We're removing just this one
remaining = remaining.concat(this.eventRegistrations_.slice(i + 1));
break;
}
}
this.eventRegistrations_ = remaining;
} else {
this.eventRegistrations_ = [];
}
return cancelEvents;
}
/**
* Applies the given Operation, updates our cache, and returns the appropriate events.
*
* @param {!Operation} operation
* @param {!WriteTreeRef} writesCache
* @param {?Node} completeServerCache
* @return {!Array.<!Event>}
*/
applyOperation(
operation: Operation,
writesCache: WriteTreeRef,
completeServerCache: Node | null
): Event[] {
if (
operation.type === OperationType.MERGE &&
operation.source.queryId !== null
) {
assert(
this.viewCache_.getCompleteServerSnap(),
'We should always have a full cache before handling merges'
);
assert(
this.viewCache_.getCompleteEventSnap(),
'Missing event cache, even though we have a server cache'
);
}
const oldViewCache = this.viewCache_;
const result = this.processor_.applyOperation(
oldViewCache,
operation,
writesCache,
completeServerCache
);
this.processor_.assertIndexed(result.viewCache);
assert(
result.viewCache.getServerCache().isFullyInitialized() ||
!oldViewCache.getServerCache().isFullyInitialized(),
'Once a server snap is complete, it should never go back'
);
this.viewCache_ = result.viewCache;
return this.generateEventsForChanges_(
result.changes,
result.viewCache.getEventCache().getNode(),
null
);
}
/**
* @param {!EventRegistration} registration
* @return {!Array.<!Event>}
*/
getInitialEvents(registration: EventRegistration): Event[] {
const eventSnap = this.viewCache_.getEventCache();
const initialChanges: Change[] = [];
if (!eventSnap.getNode().isLeafNode()) {
const eventNode = eventSnap.getNode() as ChildrenNode;
eventNode.forEachChild(PRIORITY_INDEX, function(key, childNode) {
initialChanges.push(Change.childAddedChange(key, childNode));
});
}
if (eventSnap.isFullyInitialized()) {
initialChanges.push(Change.valueChange(eventSnap.getNode()));
}
return this.generateEventsForChanges_(
initialChanges,
eventSnap.getNode(),
registration
);
}
/**
* @private
* @param {!Array.<!Change>} changes
* @param {!Node} eventCache
* @param {EventRegistration=} eventRegistration
* @return {!Array.<!Event>}
*/
generateEventsForChanges_(
changes: Change[],
eventCache: Node,
eventRegistration?: EventRegistration
): Event[] {
const registrations = eventRegistration
? [eventRegistration]
: this.eventRegistrations_;
return this.eventGenerator_.generateEventsForChanges(
changes,
eventCache,
registrations
);
}
}
|