Listen to pin/unpin tab events in Firefox Add-on SDK

Question

I am writing a Firefox Add-on SDK extension. I want to be notified when any tab is pinned or unpinned. Unfortunately, the sdk/tabs module doesn't provide such events. Is there some low-level API which provides events for pinning/unpinning tabs?

Answer 1

There is no Firefox Add-on SDK Low-Level API which provides a way to listen for tabs being pinned, or unpinned. The "Add-on SDK Low-Level APIs" are a very specific list of APIs which are defined only within the Add-on SDK. You did not limit your request to just the Add-on SDK specific APIs, but to all Firefox APIs which function within the Add-on SDK, which is almost all Firefox APIs, except WebExtensions.

You can get such events by listening for the TabPinned and TabUnpinned events on the XUL <tabs> element for the window in which you are interested. You can get the XUL <tabs> element by using getTabContainer(window). If you want to get all such events within all browser windows, you will need to add the events to the tabContainer, the XUL <tabs> element, for each browser window. You can see a list of the tab specific events in the MDN Event Reference page.

The following is a Firefox Add-on SDK based extension which will listen for TabPinned and TabUnpinned events in all windows.

index.js:

var sdkWinUtils = require('sdk/window/utils');
var sdkTabsUtils = require('sdk/tabs/utils');
var sdkWindows = require("sdk/windows");

//For testing, open the Browser Console
sdkWinUtils.getMostRecentBrowserWindow()
           .document.getElementById('menu_browserConsole').doCommand();

function tabPinned(event) {
  let tabId = sdkTabsUtils.getTabId(event.target);
  console.log('Pinned Tab ID:',tabId);
}

function tabUnpinned(event) {
  let tabId = sdkTabsUtils.getTabId(event.target);
  console.log('Unpinned Tab ID:',tabId);
}

function addTabPinUnpinListenersInWindow(win){
    //win can be either a browserWindow provided by the 
    //    sdkWindows.browserWindows.on('open',);
    //  event, or nsIDOMWindow instances provided in the array from
    //    sdkWinUtils.windows()
    //  We can distinguish between the two by using 
    //    sdkWinUtils.isBrowser(win)
    let container;
    if(sdkWinUtils.isBrowser(win)){
        container = sdkTabsUtils.getTabContainer(win);
    }else{
        let { viewFor } = require("sdk/view/core");
        container = sdkTabsUtils.getTabContainer(viewFor(win));
    }
    container.addEventListener("TabPinned", tabPinned, false);
    container.addEventListener("TabUnpinned", tabUnpinned, false);
}

function removeTabPinUnpinListenersInWindow(win){
    let container = sdkTabsUtils.getTabContainer(win);
    container.removeEventListener("TabPinned", tabPinned, false);
    container.removeEventListener("TabUnpinned", tabUnpinned, false);
}

function forEachOpenWindow(func){
    let allWindows = sdkWinUtils.windows('navigator:browser', {includePrivate:true});
    for(let win of allWindows){
        func(win);
    }
}

function forEachOpenWindowAndAllNewWindows(func){
    forEachOpenWindow(func);
    //Listen for new windows opening and add tab pin/unpin listeners:
    sdkWindows.browserWindows.on('open',func);
}

function removeAllListeners(){
    //To be called upon shutdown for add-on upgrade/disable/removal
    //Remove new window open listener
    sdkWindows.browserWindows.off('open',addTabPinUnpinListenersInWindow);
    //Remove tab pin/unpin listeners
    forEachOpenWindow(removeTabPinUnpinListenersInWindow);
}

//Add listeners to all open windows and all which open
forEachOpenWindowAndAllNewWindows(addTabPinUnpinListenersInWindow);

//Clean up if Firefox is not shutting down (e.g. the add-on is disabled by user).
exports.onUnload = reason => {
    if(reason !== 'shutdown'){
        //The add-on is being unloaded and it is not because Firefox is sutting down.
        removeAllListeners();
    }
};

package.json:

{
    "title": "Listen to tab pin/unpin",
    "name": "listen-to-tab-pin-unpin",
    "version": "0.0.1",
    "description": "Output to console when a tab is pinned or unpinned.",
    "main": "index.js",
    "author": "Makyen",
    "permissions": {"private-browsing": true},
    "engines": {
        "firefox": ">=38.0a1",
        "fennec": ">=38.0a1"
    },
    "license": "MIT",
    "keywords": [
        "jetpack"
    ]
}