diff options
Diffstat (limited to 'devtools/shared/commands/root-resource/root-resource-command.js')
| -rw-r--r-- | devtools/shared/commands/root-resource/root-resource-command.js | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/devtools/shared/commands/root-resource/root-resource-command.js b/devtools/shared/commands/root-resource/root-resource-command.js new file mode 100644 index 0000000000..1071d1bcb1 --- /dev/null +++ b/devtools/shared/commands/root-resource/root-resource-command.js @@ -0,0 +1,348 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +"use strict"; + +const { throttle } = require("resource://devtools/shared/throttle.js"); + +class RootResourceCommand { + /** + * This class helps retrieving existing and listening to "root" resources. + * + * This is a fork of ResourceCommand, but specific to context-less + * resources which can be listened to right away when connecting to the RDP server. + * + * The main difference in term of implementation is that: + * - we receive a root front as constructor argument (instead of `commands` object) + * - we only listen for RDP events on the Root actor (instead of watcher and target actors) + * - there is no legacy listener support + * - there is no resource transformers + * - there is a lot of logic around targets that is removed here. + * + * See ResourceCommand for comments and jsdoc. + * + * TODO Bug 1758530 - Investigate sharing code with ResourceCommand instead of forking. + * + * @param object commands + * The commands object with all interfaces defined from devtools/shared/commands/ + * @param object rootFront + * Front for the Root actor. + */ + constructor({ commands, rootFront }) { + this.rootFront = rootFront ? rootFront : commands.client.mainRoot; + + this._onResourceAvailable = this._onResourceAvailable.bind(this); + this._onResourceDestroyed = this._onResourceDestroyed.bind(this); + + this._watchers = []; + + this._pendingWatchers = new Set(); + + this._cache = []; + this._listenedResources = new Set(); + + this._processingExistingResources = new Set(); + + this._notifyWatchers = this._notifyWatchers.bind(this); + this._throttledNotifyWatchers = throttle(this._notifyWatchers, 100); + } + + getAllResources(resourceType) { + return this._cache.filter(r => r.resourceType === resourceType); + } + + getResourceById(resourceType, resourceId) { + return this._cache.find( + r => r.resourceType === resourceType && r.resourceId === resourceId + ); + } + + async watchResources(resources, options) { + const { + onAvailable, + onUpdated, + onDestroyed, + ignoreExistingResources = false, + } = options; + + if (typeof onAvailable !== "function") { + throw new Error( + "RootResourceCommand.watchResources expects an onAvailable function as argument" + ); + } + + for (const type of resources) { + if (!this._isValidResourceType(type)) { + throw new Error( + `RootResourceCommand.watchResources invoked with an unknown type: "${type}"` + ); + } + } + + const pendingWatcher = { + resources, + onAvailable, + }; + this._pendingWatchers.add(pendingWatcher); + + if (!this._listenerRegistered) { + this._listenerRegistered = true; + this.rootFront.on("resource-available-form", this._onResourceAvailable); + this.rootFront.on("resource-destroyed-form", this._onResourceDestroyed); + } + + const promises = []; + for (const resource of resources) { + promises.push(this._startListening(resource)); + } + await Promise.all(promises); + + this._notifyWatchers(); + + this._pendingWatchers.delete(pendingWatcher); + + const watchedResources = pendingWatcher.resources; + + if (!watchedResources.length) { + return; + } + + this._watchers.push({ + resources: watchedResources, + onAvailable, + onUpdated, + onDestroyed, + pendingEvents: [], + }); + + if (!ignoreExistingResources) { + await this._forwardExistingResources(watchedResources, onAvailable); + } + } + + unwatchResources(resources, options) { + const { onAvailable } = options; + + if (typeof onAvailable !== "function") { + throw new Error( + "RootResourceCommand.unwatchResources expects an onAvailable function as argument" + ); + } + + for (const type of resources) { + if (!this._isValidResourceType(type)) { + throw new Error( + `RootResourceCommand.unwatchResources invoked with an unknown type: "${type}"` + ); + } + } + + const allWatchers = [...this._watchers, ...this._pendingWatchers]; + for (const watcherEntry of allWatchers) { + if (watcherEntry.onAvailable == onAvailable) { + watcherEntry.resources = watcherEntry.resources.filter(resourceType => { + return !resources.includes(resourceType); + }); + } + } + this._watchers = this._watchers.filter(entry => { + return !!entry.resources.length; + }); + + for (const resource of resources) { + const isResourceWatched = allWatchers.some(watcherEntry => + watcherEntry.resources.includes(resource) + ); + + if (!isResourceWatched && this._listenedResources.has(resource)) { + this._stopListening(resource); + } + } + } + + clearResources(resourceTypes) { + if (!Array.isArray(resourceTypes)) { + throw new Error("clearResources expects an array of resource types"); + } + // Clear the cached resources of the type. + this._cache = this._cache.filter( + cachedResource => !resourceTypes.includes(cachedResource.resourceType) + ); + + if (resourceTypes.length) { + this.rootFront.clearResources(resourceTypes); + } + } + + async waitForNextResource( + resourceType, + { ignoreExistingResources = false, predicate } = {} + ) { + predicate = predicate || (resource => !!resource); + + let resolve; + const promise = new Promise(r => (resolve = r)); + const onAvailable = async resources => { + const matchingResource = resources.find(resource => predicate(resource)); + if (matchingResource) { + this.unwatchResources([resourceType], { onAvailable }); + resolve(matchingResource); + } + }; + + await this.watchResources([resourceType], { + ignoreExistingResources, + onAvailable, + }); + return { onResource: promise }; + } + + async _onResourceAvailable(resources) { + for (const resource of resources) { + const { resourceType } = resource; + + resource.isAlreadyExistingResource = + this._processingExistingResources.has(resourceType); + + this._queueResourceEvent("available", resourceType, resource); + + this._cache.push(resource); + } + + this._throttledNotifyWatchers(); + } + + async _onResourceDestroyed(resources) { + for (const resource of resources) { + const { resourceType, resourceId } = resource; + + let index = -1; + if (resourceId) { + index = this._cache.findIndex( + cachedResource => + cachedResource.resourceType == resourceType && + cachedResource.resourceId == resourceId + ); + } else { + index = this._cache.indexOf(resource); + } + if (index >= 0) { + this._cache.splice(index, 1); + } else { + console.warn( + `Resource ${resourceId || ""} of ${resourceType} was not found.` + ); + } + + this._queueResourceEvent("destroyed", resourceType, resource); + } + this._throttledNotifyWatchers(); + } + + _queueResourceEvent(callbackType, resourceType, update) { + for (const { resources, pendingEvents } of this._watchers) { + if (!resources.includes(resourceType)) { + continue; + } + if (pendingEvents.length) { + const lastEvent = pendingEvents[pendingEvents.length - 1]; + if (lastEvent.callbackType == callbackType) { + lastEvent.updates.push(update); + continue; + } + } + pendingEvents.push({ + callbackType, + updates: [update], + }); + } + } + + _notifyWatchers() { + for (const watcherEntry of this._watchers) { + const { onAvailable, onDestroyed, pendingEvents } = watcherEntry; + watcherEntry.pendingEvents = []; + + for (const { callbackType, updates } of pendingEvents) { + try { + if (callbackType == "available") { + onAvailable(updates, { areExistingResources: false }); + } else if (callbackType == "destroyed" && onDestroyed) { + onDestroyed(updates); + } + } catch (e) { + console.error( + "Exception while calling a RootResourceCommand", + callbackType, + "callback", + ":", + e + ); + } + } + } + } + + _isValidResourceType(type) { + return this.ALL_TYPES.includes(type); + } + + async _startListening(resourceType) { + if (this._listenedResources.has(resourceType)) { + return; + } + this._listenedResources.add(resourceType); + + this._processingExistingResources.add(resourceType); + + // For now, if the server doesn't support the resource type + // act as if we were listening, but do nothing. + // Calling watchResources/unwatchResources will work fine, + // but no resource will be notified. + if (this.rootFront.traits.resources?.[resourceType]) { + await this.rootFront.watchResources([resourceType]); + } else { + console.warn( + `Ignored watchRequest, resourceType "${resourceType}" not found in rootFront.traits.resources` + ); + } + this._processingExistingResources.delete(resourceType); + } + + async _forwardExistingResources(resourceTypes, onAvailable) { + const existingResources = this._cache.filter(resource => + resourceTypes.includes(resource.resourceType) + ); + if (existingResources.length) { + await onAvailable(existingResources, { areExistingResources: true }); + } + } + + _stopListening(resourceType) { + if (!this._listenedResources.has(resourceType)) { + throw new Error( + `Stopped listening for resource '${resourceType}' that isn't being listened to` + ); + } + this._listenedResources.delete(resourceType); + + this._cache = this._cache.filter( + cachedResource => cachedResource.resourceType !== resourceType + ); + + if ( + !this.rootFront.isDestroyed() && + this.rootFront.traits.resources?.[resourceType] + ) { + this.rootFront.unwatchResources([resourceType]); + } + } +} + +RootResourceCommand.TYPES = RootResourceCommand.prototype.TYPES = { + EXTENSIONS_BGSCRIPT_STATUS: "extensions-backgroundscript-status", +}; +RootResourceCommand.ALL_TYPES = RootResourceCommand.prototype.ALL_TYPES = + Object.values(RootResourceCommand.TYPES); +module.exports = RootResourceCommand; |