playcanvas/build/playcanvas/src/core/event-handler.js

PlayCanvas WebGL game engine

import { EventHandle } from './event-handle.js';

class EventHandler {
		initEventHandler() {
				this._callbacks = new Map();
				this._callbackActive = new Map();
		}
		_addCallback(name, callback, scope, once) {
				if (!this._callbacks.has(name)) {
						this._callbacks.set(name, []);
				}
				if (this._callbackActive.has(name)) {
						const callbackActive = this._callbackActive.get(name);
						if (callbackActive && callbackActive === this._callbacks.get(name)) {
								this._callbackActive.set(name, callbackActive.slice());
						}
				}
				const evt = new EventHandle(this, name, callback, scope, once);
				this._callbacks.get(name).push(evt);
				return evt;
		}
		on(name, callback, scope = this) {
				return this._addCallback(name, callback, scope, false);
		}
		once(name, callback, scope = this) {
				return this._addCallback(name, callback, scope, true);
		}
		off(name, callback, scope) {
				if (name) {
						if (this._callbackActive.has(name) && this._callbackActive.get(name) === this._callbacks.get(name)) {
								this._callbackActive.set(name, this._callbackActive.get(name).slice());
						}
				} else {
						for (const [key, callbacks] of this._callbackActive){
								if (!this._callbacks.has(key)) {
										continue;
								}
								if (this._callbacks.get(key) !== callbacks) {
										continue;
								}
								this._callbackActive.set(key, callbacks.slice());
						}
				}
				if (!name) {
						for (const callbacks of this._callbacks.values()){
								for(let i = 0; i < callbacks.length; i++){
										callbacks[i].removed = true;
								}
						}
						this._callbacks.clear();
				} else if (!callback) {
						const callbacks = this._callbacks.get(name);
						if (callbacks) {
								for(let i = 0; i < callbacks.length; i++){
										callbacks[i].removed = true;
								}
								this._callbacks.delete(name);
						}
				} else {
						const callbacks = this._callbacks.get(name);
						if (!callbacks) {
								return this;
						}
						for(let i = 0; i < callbacks.length; i++){
								if (callbacks[i].callback !== callback) {
										continue;
								}
								if (scope && callbacks[i].scope !== scope) {
										continue;
								}
								callbacks[i].removed = true;
								callbacks.splice(i, 1);
								i--;
						}
						if (callbacks.length === 0) {
								this._callbacks.delete(name);
						}
				}
				return this;
		}
		offByHandle(handle) {
				const name = handle.name;
				handle.removed = true;
				if (this._callbackActive.has(name) && this._callbackActive.get(name) === this._callbacks.get(name)) {
						this._callbackActive.set(name, this._callbackActive.get(name).slice());
				}
				const callbacks = this._callbacks.get(name);
				if (!callbacks) {
						return this;
				}
				const ind = callbacks.indexOf(handle);
				if (ind !== -1) {
						callbacks.splice(ind, 1);
						if (callbacks.length === 0) {
								this._callbacks.delete(name);
						}
				}
				return this;
		}
		fire(name, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8) {
				if (!name) {
						return this;
				}
				const callbacksInitial = this._callbacks.get(name);
				if (!callbacksInitial) {
						return this;
				}
				let callbacks;
				if (!this._callbackActive.has(name)) {
						this._callbackActive.set(name, callbacksInitial);
				} else if (this._callbackActive.get(name) !== callbacksInitial) {
						callbacks = callbacksInitial.slice();
				}
				for(let i = 0; (callbacks || this._callbackActive.get(name)) && i < (callbacks || this._callbackActive.get(name)).length; i++){
						const evt = (callbacks || this._callbackActive.get(name))[i];
						if (!evt.callback) continue;
						evt.callback.call(evt.scope, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
						if (evt._once) {
								const existingCallback = this._callbacks.get(name);
								const ind = existingCallback ? existingCallback.indexOf(evt) : -1;
								if (ind !== -1) {
										if (this._callbackActive.get(name) === existingCallback) {
												this._callbackActive.set(name, this._callbackActive.get(name).slice());
										}
										const callbacks = this._callbacks.get(name);
										if (!callbacks) continue;
										callbacks[ind].removed = true;
										callbacks.splice(ind, 1);
										if (callbacks.length === 0) {
												this._callbacks.delete(name);
										}
								}
						}
				}
				if (!callbacks) {
						this._callbackActive.delete(name);
				}
				return this;
		}
		hasEvent(name) {
				return !!this._callbacks.get(name)?.length;
		}
		constructor(){
				this._callbacks = new Map();
				this._callbackActive = new Map();
		}
}

export { EventHandler };