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/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* vim: set sts=2 sw=2 et tw=80: */
/* 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
* This module contains utilities for interacting with DevTools
* from the child process.
*/
// Create a variable to hold the cached ThemeChangeObserver which does not
// get created until a devtools context has been created.
let themeChangeObserver;
/**
* An observer that watches for changes to the devtools theme and provides
* that information to the devtools.panels.themeName API property, as well as
* emits events for the devtools.panels.onThemeChanged event. It also caches
* the current value of devtools.themeName.
*/
class ThemeChangeObserver extends EventEmitter {
constructor(themeName, onDestroyed) {
super();
this.themeName = themeName;
this.onDestroyed = onDestroyed;
this.contexts = new Set();
Services.cpmm.addMessageListener("Extension:DevToolsThemeChanged", this);
}
addContext(context) {
if (this.contexts.has(context)) {
throw new Error(
"addContext on the ThemeChangeObserver was called more than once" +
" for the context."
);
}
context.callOnClose({
close: () => this.onContextClosed(context),
});
this.contexts.add(context);
}
onContextClosed(context) {
this.contexts.delete(context);
if (this.contexts.size === 0) {
this.destroy();
}
}
onThemeChanged(themeName) {
// Update the cached themeName and emit an event for the API.
this.themeName = themeName;
this.emit("themeChanged", themeName);
}
receiveMessage({ name, data }) {
if (name === "Extension:DevToolsThemeChanged") {
this.onThemeChanged(data.themeName);
}
}
destroy() {
Services.cpmm.removeMessageListener("Extension:DevToolsThemeChanged", this);
this.onDestroyed();
this.onDestroyed = null;
this.contexts.clear();
this.contexts = null;
}
}
export var ExtensionChildDevToolsUtils = {
/**
* Creates an cached instance of the ThemeChangeObserver class and
* initializes it with the current themeName. This cached instance is
* destroyed when all of the contexts added to it are closed.
*
* @param {string} themeName The name of the current devtools theme.
* @param {import("ExtensionPageChild.sys.mjs").DevToolsContextChild} context
* The newly created devtools page context.
*/
initThemeChangeObserver(themeName, context) {
if (!themeChangeObserver) {
themeChangeObserver = new ThemeChangeObserver(themeName, function () {
themeChangeObserver = null;
});
}
themeChangeObserver.addContext(context);
},
/**
* Returns the cached instance of ThemeChangeObserver.
*
* @returns {ThemeChangeObserver} The cached instance of ThemeChangeObserver.
*/
getThemeChangeObserver() {
if (!themeChangeObserver) {
throw new Error(
"A ThemeChangeObserver must be created before being retrieved."
);
}
return themeChangeObserver;
},
};