repo: Add a utility for reloading applets on code change

.gitignore

@@ -1,3 +1,4 @@
 *.mo
 *.pyc
 */gschemas.compiled
+node_modules/

README.md

@@ -131,4 +131,13 @@ Test your translations `.po` locally before uploading to Spices:"
 More info:
 ```
 ./cinnamon-spices-makepot --help
-```
+```
+
+# Auto-reloading applets
+
+A utility script using Gulp is provided that can automatically reload applets on code change. To use, install the [latest NodeJS LTS release](https://github.com/nodesource/distributions).
+- Run `npm install -g gulp@^4.0.0`
+- In the root of this repo's directory run `npm install`.
+- To use the script, run ```gulp watch --uuid="<applet uuid>"```
+
+For more info run ```gulp help```.

gulpfile.js

@@ -0,0 +1,132 @@
+const fs = require('fs');
+const os = require('os');
+const gulp = require('gulp');
+const clear = require('clear');
+const {exec, execSync} = require('child_process');
+
+const getArgs = function() {
+    const argv = require('yargs')
+    .option('uuid', {
+        alias: 'u'
+    })
+    .argv;
+
+    const UUID = argv.u;
+
+    if (!UUID) {
+        throw new Error('Unable to get the UUID.');
+    }
+
+    return UUID;
+}
+
+gulp.task('install', (done) => {
+    const UUID = getArgs();
+    const homeDir = os.homedir();
+    const systemXletDir = `${homeDir}/.local/share/cinnamon/applets/${UUID}/`;
+    const localXletDir = `./${UUID}/files/${UUID}/`;
+    const systemDirExists = fs.existsSync(systemXletDir);
+    const localDirExists = fs.existsSync(localXletDir);
+    const userInfo = os.userInfo();
+
+    if (!systemDirExists) {
+        console.log(
+            'Xlet does not exist in the system directory. Attempting to create the directory:\n' +
+            systemXletDir
+        );
+        execSync(`mkdir ${systemXletDir}`);
+    }
+
+    if (!localDirExists) {
+        throw new Error('Xlet does not exist in the local directory.');
+    }
+
+    const {uid, gid} = fs.statSync(systemXletDir);
+
+    if (uid !== userInfo.uid || gid !== userInfo.gid) {
+        throw new Error(`Incorrect permission are set for the applets directory. Please run 'gulp help'.`);
+    }
+
+    exec(`rm -rf ${systemXletDir} && ` +
+        `cp -arf ${localXletDir} ${systemXletDir}`,
+        function(err, stdout, stderr) {
+            console.log(stdout);
+            console.log(stderr);
+            done();
+        }
+    );
+});
+
+const reload = function(done) {
+    const UUID = getArgs();
+    exec(
+        'dbus-send --session --dest=org.Cinnamon.LookingGlass --type=method_call '
+        + '/org/Cinnamon/LookingGlass org.Cinnamon.LookingGlass.ReloadExtension '
+        + `string:'${UUID}' string:'APPLET'`,
+        function(err, stdout, stderr) {
+            console.log(stdout);
+            console.log(stderr);
+            done();
+        }
+    );
+};
+
+gulp.task('reload', gulp.series('install', reload));
+
+gulp.task('_watch', (done) => {
+    const UUID = getArgs();
+    const localXletDir = `./${UUID}/files/${UUID}`;
+    const glob = `${localXletDir}/**/**/**/*.{js,json,py,css,po}`;
+    const localDirExists = fs.existsSync(localXletDir);
+
+    if (!localDirExists) {
+       throw new Error('Xlet does not exist in the local directory.');
+    }
+
+    console.log(`Watching glob pattern: ${glob}`)
+    gulp.watch(glob)
+    .on('change', gulp.parallel('reload'));
+    done();
+});
+
+gulp.task('clear-terminal', (done) => {
+    clear();
+    done();
+});
+
+gulp.task('watch', gulp.series('clear-terminal', (done) => {
+    let [, , , uuid] = process.argv;
+    let spawnWatch = () => {
+        let proc = require('child_process').spawn('gulp', ['_watch', uuid], {stdio: 'inherit'});
+        proc.on('close', function(code) {
+            spawnWatch();
+        });
+    };
+    spawnWatch();
+    done();
+}));
+
+gulp.task('help', gulp.series('clear-terminal', (done) => {
+    console.log(
+        `Usage: gulp watch [flags]
+
+        This file uses gulp to provide a watch task for xlet development.
+        It will copy the xlet files from the UUID directory specified and
+        auto-reload the applet on code change.
+
+        Install gulp globally.
+
+        npm: 'npm install -g gulp@^4.0.0'
+        yarn: 'yarn global add gulp@^4.0.0'
+
+        To use this script, run 'gulp watch --uuid="<xlet uuid>"'.
+        Example: 'gulp watch --uuid="grouped-window-list@cinnamon.org"'
+
+        Options:
+            --uuid                 UUID of the xlet to watch.
+        `
+    );
+    done();
+}));
+
+gulp.task('default', gulp.series('watch', (done) => done()));