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Diffstat (limited to '')
-rw-r--r-- | devtools/client/inspector/shared/walker-event-listener.js | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/devtools/client/inspector/shared/walker-event-listener.js b/devtools/client/inspector/shared/walker-event-listener.js new file mode 100644 index 0000000000..322c3be6df --- /dev/null +++ b/devtools/client/inspector/shared/walker-event-listener.js @@ -0,0 +1,86 @@ +/* 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"; + +/** + * WalkerEventListener provides a mechanism to listen the walker event of the inspector + * while reflecting the updating of TargetCommand. + */ +class WalkerEventListener { + /** + * @param {Inspector} - inspector + * @param {Object} - listenerMap + * The structure of listenerMap should be as follows. + * { + * walkerEventName1: eventHandler1, + * walkerEventName2: eventHandler2, + * ... + * } + */ + constructor(inspector, listenerMap) { + this._inspector = inspector; + this._listenerMap = listenerMap; + this._onTargetAvailable = this._onTargetAvailable.bind(this); + this._onTargetDestroyed = this._onTargetDestroyed.bind(this); + + this._init(); + } + + /** + * Clean up function. + */ + destroy() { + this._inspector.commands.targetCommand.unwatchTargets({ + types: [this._inspector.commands.targetCommand.TYPES.FRAME], + onAvailable: this._onTargetAvailable, + onDestroyed: this._onTargetDestroyed, + }); + + const targets = this._inspector.commands.targetCommand.getAllTargets([ + this._inspector.commands.targetCommand.TYPES.FRAME, + ]); + for (const targetFront of targets) { + this._onTargetDestroyed({ + targetFront, + }); + } + + this._inspector = null; + this._listenerMap = null; + } + + _init() { + this._inspector.commands.targetCommand.watchTargets({ + types: [this._inspector.commands.targetCommand.TYPES.FRAME], + onAvailable: this._onTargetAvailable, + onDestroyed: this._onTargetDestroyed, + }); + } + + async _onTargetAvailable({ targetFront }) { + const inspectorFront = await targetFront.getFront("inspector"); + // In case of multiple fast navigations, the front may already be destroyed, + // in such scenario bail out and ignore this short lived target. + if (inspectorFront.isDestroyed() || !this._listenerMap) { + return; + } + const { walker } = inspectorFront; + for (const [name, listener] of Object.entries(this._listenerMap)) { + walker.on(name, listener); + } + } + + _onTargetDestroyed({ targetFront }) { + const inspectorFront = targetFront.getCachedFront("inspector"); + if (inspectorFront) { + const { walker } = inspectorFront; + for (const [name, listener] of Object.entries(this._listenerMap)) { + walker.off(name, listener); + } + } + } +} + +module.exports = WalkerEventListener; |