Add support for nitrogen on linux

lib/linux.js

@@ -1,9 +1,12 @@
 'use strict';
 const path = require('path');
+const homeDir = require('os').homedir();
 const childProcess = require('child_process');
+const fileSystem = require('fs');
 const pify = require('pify');
 
 const cp = pify(childProcess);
+const fs = pify(fileSystem);
 
 const appsList = [
 	{
@@ -31,6 +34,12 @@ const appsList = [
 		cmd: 'feh',
 		set: ['--bg-scale', '%s']
 	},
+	{
+		cmd: 'nitrogen',
+		set: ['--set-zoom-fill', '--save', '%s'],
+		get: [],
+		transform: imagePath => imagePath.trim().split('\n').slice(-1)[0]
+	},
 	{
 		cmd: 'xfconf-query',
 		set: ['-c xfce4-desktop',
@@ -63,18 +72,6 @@ const appsList = [
 			'/org/mate/desktop/background/picture-filename'
 		],
 		transform: imagePath => imagePath.slice(1, -1)
-	},
-	{
-		cmd: 'gsettings',
-		set: ['set',
-			'org.cinnamon.desktop.background',
-			'picture-uri',
-			'file://%s'
-		],
-		get: ['get',
-			'org.cinnamon.desktop.background',
-			'picture-uri'
-		]
 	}
 ];
 
@@ -100,12 +97,12 @@ function setAvailableApps() {
 			throw new Error('None of the apps were found');
 		}
 
-		// it may return aliases so we only want the real path
+		// It may return aliases so we only want the real path
 		// and only the executable name. i.e. 'foo' from /bin/foo
 		stdout = stdout.split('\n');
 
 		stdout.forEach(el => {
-			// it's an alias
+			// It's an alias
 			if (el[0] !== path.sep) {
 				return;
 			}
@@ -117,13 +114,46 @@ function setAvailableApps() {
 	});
 }
 
+function isCinnamon() {
+	const args = ['writable', 'org.cinnamon.desktop.background', 'picture-uri'];
+
+	return cp.execFile('gsettings', args)
+		.then(out => out.trim() === 'true')
+		.catch(() => {});
+}
+
 exports.get = function get() {
 	if (!availableApps) {
 		return setAvailableApps().then(get);
 	}
 
 	const app = availableApps.find(app => app.get);
 
+	if (app.cmd === 'nitrogen') {
+		const configFile = path.join(homeDir, '.config/nitrogen/bg-saved.cfg');
+		return fs.readFile(configFile, 'utf8').then(config =>
+			config.trim().split('\n').find(line => line.startsWith('file=')).replace('file=', '')
+		);
+	}
+
+	if (app.cmd === 'gsettings') {
+		return isCinnamon().then(cinnamon => {
+			const getArgs = app.get.slice();
+			if (cinnamon) {
+				getArgs[1] = 'org.cinnamon.desktop.background';
+			}
+			return cp.execFile(app.cmd, getArgs).then(stdout => {
+				stdout = stdout.trim();
+
+				if (typeof app.transform === 'function') {
+					return app.transform(stdout);
+				}
+
+				return stdout;
+			});
+		});
+	}
+
 	return cp.execFile(app.cmd, app.get).then(stdout => {
 		stdout = stdout.trim();
 
@@ -149,5 +179,14 @@ exports.set = function set(imagePath) {
 
 	params[params.length - 1] = params[params.length - 1].replace('%s', path.resolve(imagePath));
 
+	if (app.cmd === 'gsettings') {
+		return isCinnamon().then(cinnamon => {
+			if (cinnamon) {
+				params[1] = 'org.cinnamon.desktop.background';
+			}
+			return cp.execFile(app.cmd, params);
+		});
+	}
+
 	return cp.execFile(app.cmd, params);
 };