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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 { DataSnapshot } from '../../api/DataSnapshot';
import { DataEvent, CancelEvent, Event } from './Event';
import { contains, getCount, getAnyKey, every } from '@firebase/util';
import { assert } from '@firebase/util';
import { Path } from '../util/Path';
import { Change } from './Change';
import { Query } from '../../api/Query';
/**
* An EventRegistration is basically an event type ('value', 'child_added', etc.) and a callback
* to be notified of that type of event.
*
* That said, it can also contain a cancel callback to be notified if the event is canceled. And
* currently, this code is organized around the idea that you would register multiple child_ callbacks
* together, as a single EventRegistration. Though currently we don't do that.
*/
export interface EventRegistration {
/**
* True if this container has a callback to trigger for this event type
* @param {!string} eventType
* @return {boolean}
*/
respondsTo(eventType: string): boolean;
/**
* @param {!Change} change
* @param {!Query} query
* @return {!Event}
*/
createEvent(change: Change, query: Query): Event;
/**
* Given event data, return a function to trigger the user's callback
* @param {!Event} eventData
* @return {function()}
*/
getEventRunner(eventData: Event): () => void;
/**
* @param {!Error} error
* @param {!Path} path
* @return {?CancelEvent}
*/
createCancelEvent(error: Error, path: Path): CancelEvent | null;
/**
* @param {!EventRegistration} other
* @return {boolean}
*/
matches(other: EventRegistration): boolean;
/**
* False basically means this is a "dummy" callback container being used as a sentinel
* to remove all callback containers of a particular type. (e.g. if the user does
* ref.off('value') without specifying a specific callback).
*
* (TODO: Rework this, since it's hacky)
*
* @return {boolean}
*/
hasAnyCallback(): boolean;
}
/**
* Represents registration for 'value' events.
*/
export class ValueEventRegistration implements EventRegistration {
/**
* @param {?function(!DataSnapshot)} callback_
* @param {?function(Error)} cancelCallback_
* @param {?Object} context_
*/
constructor(
private callback_: ((d: DataSnapshot) => void) | null,
private cancelCallback_: ((e: Error) => void) | null,
private context_: Object | null
) {}
/**
* @inheritDoc
*/
respondsTo(eventType: string): boolean {
return eventType === 'value';
}
/**
* @inheritDoc
*/
createEvent(change: Change, query: Query): DataEvent {
const index = query.getQueryParams().getIndex();
return new DataEvent(
'value',
this,
new DataSnapshot(change.snapshotNode, query.getRef(), index)
);
}
/**
* @inheritDoc
*/
getEventRunner(eventData: CancelEvent | DataEvent): () => void {
const ctx = this.context_;
Iif (eventData.getEventType() === 'cancel') {
assert(
this.cancelCallback_,
'Raising a cancel event on a listener with no cancel callback'
);
const cancelCB = this.cancelCallback_;
return function() {
// We know that error exists, we checked above that this is a cancel event
cancelCB.call(ctx, (eventData as CancelEvent).error);
};
} else {
const cb = this.callback_;
return function() {
cb.call(ctx, (eventData as DataEvent).snapshot);
};
}
}
/**
* @inheritDoc
*/
createCancelEvent(error: Error, path: Path): CancelEvent | null {
if (this.cancelCallback_) {
return new CancelEvent(this, error, path);
} else {
return null;
}
}
/**
* @inheritDoc
*/
matches(other: EventRegistration): boolean {
Iif (!(other instanceof ValueEventRegistration)) {
return false;
} else if (!other.callback_ || !this.callback_) {
// If no callback specified, we consider it to match any callback.
return true;
} else {
return (
other.callback_ === this.callback_ && other.context_ === this.context_
);
}
}
/**
* @inheritDoc
*/
hasAnyCallback(): boolean {
return this.callback_ !== null;
}
}
/**
* Represents the registration of 1 or more child_xxx events.
*
* Currently, it is always exactly 1 child_xxx event, but the idea is we might let you
* register a group of callbacks together in the future.
*
* @constructor
* @implements {EventRegistration}
*/
export class ChildEventRegistration implements EventRegistration {
/**
* @param {?Object.<string, function(!DataSnapshot, ?string=)>} callbacks_
* @param {?function(Error)} cancelCallback_
* @param {Object=} context_
*/
constructor(
private callbacks_:
| ({ [k: string]: (d: DataSnapshot, s?: string | null) => void })
| null,
private cancelCallback_: ((e: Error) => void) | null,
private context_?: Object
) {}
/**
* @inheritDoc
*/
respondsTo(eventType: string): boolean {
let eventToCheck =
eventType === 'children_added' ? 'child_added' : eventType;
eventToCheck =
eventToCheck === 'children_removed' ? 'child_removed' : eventToCheck;
return contains(this.callbacks_, eventToCheck);
}
/**
* @inheritDoc
*/
createCancelEvent(error: Error, path: Path): CancelEvent | null {
if (this.cancelCallback_) {
return new CancelEvent(this, error, path);
} else {
return null;
}
}
/**
* @inheritDoc
*/
createEvent(change: Change, query: Query): DataEvent {
assert(change.childName != null, 'Child events should have a childName.');
const ref = query.getRef().child(/** @type {!string} */ (change.childName));
const index = query.getQueryParams().getIndex();
return new DataEvent(
change.type as any,
this,
new DataSnapshot(change.snapshotNode, ref, index as any),
change.prevName
);
}
/**
* @inheritDoc
*/
getEventRunner(eventData: CancelEvent | DataEvent): () => void {
const ctx = this.context_;
Iif (eventData.getEventType() === 'cancel') {
assert(
this.cancelCallback_,
'Raising a cancel event on a listener with no cancel callback'
);
const cancelCB = this.cancelCallback_;
return function() {
// We know that error exists, we checked above that this is a cancel event
cancelCB.call(ctx, (eventData as CancelEvent).error);
};
} else {
const cb = this.callbacks_[(eventData as DataEvent).eventType];
return function() {
cb.call(
ctx,
(eventData as DataEvent).snapshot,
(eventData as DataEvent).prevName
);
};
}
}
/**
* @inheritDoc
*/
matches(other: EventRegistration): boolean {
if (other instanceof ChildEventRegistration) {
if (!this.callbacks_ || !other.callbacks_) {
return true;
} else if (this.context_ === other.context_) {
const otherCount = getCount(other.callbacks_);
const thisCount = getCount(this.callbacks_);
Eif (otherCount === thisCount) {
// If count is 1, do an exact match on eventType, if either is defined but null, it's a match.
// If event types don't match, not a match
// If count is not 1, exact match across all
Eif (otherCount === 1) {
const otherKey /** @type {!string} */ = getAnyKey(other.callbacks_);
const thisKey /** @type {!string} */ = getAnyKey(this.callbacks_);
return (
thisKey === otherKey &&
(!other.callbacks_[otherKey] ||
!this.callbacks_[thisKey] ||
other.callbacks_[otherKey] === this.callbacks_[thisKey])
);
} else {
// Exact match on each key.
return every(
this.callbacks_,
(eventType, cb) => other.callbacks_[eventType] === cb
);
}
}
}
}
return false;
}
/**
* @inheritDoc
*/
hasAnyCallback(): boolean {
return this.callbacks_ !== null;
}
}
|