Eliminate ruby dependency. Closes gh-23.

The plugin now uses libsass library for fast node.js compilation.

If compiled file uses compass or it is in .sass format, the plugin
will fallback to ruby compilation.

Ruby compilation can be forced in config.

index.js

@@ -0,0 +1,147 @@
+var cp = require('child_process'), spawn = cp.spawn, exec = cp.exec;
+var sysPath = require('path');
+var progeny = require('progeny');
+var libsass = require('node-sass');
+var Promise = require('promise');
+var os = require('os');
+
+var isWindows = os.platform() === 'win32';
+var compassRe = /compass/;
+var sassRe = /\.sass$/;
+
+var extend = function(object, source) {
+  for (var key in source) object[key] = source[key];
+  return object;
+};
+
+function SassCompiler(cfg) {
+  if (cfg == null) cfg = {};
+  this.rootPath = cfg.paths.root;
+  this.optimize = cfg.optimize;
+  this.config = (cfg.plugins && cfg.plugins.sass) || {};
+  this.mode = this.config.mode;
+  this.getDependencies = progeny({
+    rootPath: this.rootPath
+  });
+  this.gem_home = this.config.gem_home;
+  this.env = {};
+  if (this.gem_home) {
+    var env = extend({}, process.env);
+    env.GEM_HOME = this.gem_home;
+    this.env = {
+      env: env
+    };
+    this._bin = "" + this.gem_home + "/bin/sass";
+    this._compass_bin = "" + this.gem_home + "/bin/compass";
+  }
+  this.bundler = this.config.useBundler;
+  this.prefix = this.bundler ? 'bundle exec ' : '';
+}
+
+SassCompiler.prototype.brunchPlugin = true;
+SassCompiler.prototype.type = 'stylesheet';
+SassCompiler.prototype.extension = 'scss';
+SassCompiler.prototype.pattern = /\.s[ac]ss$/;
+SassCompiler.prototype._bin = isWindows ? 'sass.bat' : 'sass';
+SassCompiler.prototype._compass_bin = 'compass';
+
+SassCompiler.prototype._checkRuby = function() {
+  var prefix = this.prefix;
+  var env = this.env;
+  var sassCmd = "" + this.prefix + this._bin + " --version";
+  var compassCmd = "" + this.prefix + this._compass_bin + " --version";
+
+  var sassPromise = new Promise(function(resolve, reject) {
+    exec(sassCmd, env, function(error) {
+      if (error) {
+        console.error("You need to have Sass on your system");
+        console.error("Execute `gem install sass`");
+        reject();
+      } else {
+        resolve();
+      }
+    });
+  });
+  var compassPromise = new Promise((function(resolve, reject) {
+    exec(compassCmd, env, (function(error) {
+      this.compass = !error;
+      resolve();
+    }).bind(this));
+  }).bind(this));
+  this.rubyPromise = Promise.all([sassPromise, compassPromise]);
+};
+
+SassCompiler.prototype._nativeCompile = function(data, path, callback) {
+  libsass.render({
+    data: data,
+    success: (function(css) {
+      callback(null, css);
+    }),
+    error: (function(error) {
+      callback(error);
+    }),
+    includePaths: [this.rootPath, sysPath.dirname(path)],
+    outputStyle: 'nested',
+    sourceComments: !this.optimize
+  });
+};
+
+SassCompiler.prototype._rubyCompile = function(data, path, callback) {
+  if (this.rubyPromise == null) this._checkRuby();
+  var result = '';
+  var error = null;
+  var cmd = [
+    'sass',
+    '--stdin',
+    '--load-path', this.rootPath,
+    '--load-path', sysPath.dirname(path),
+    '--no-cache'
+  ];
+  if (this.bundler) cmd.unshift('bundle', 'exec');
+
+  var debugMode = this.config.debug, hasComments;
+  if ((debugMode === 'comments' || debugMode === 'debug') && !this.optimize) {
+    hasComments = this.config.debug === 'comments';
+    cmd.push(hasComments ? '--line-comments' : '--debug-info');
+  }
+
+  if (!sassRe.test(path)) cmd.push('--scss');
+  if (this.compass) cmd.push('--compass');
+  if (this.config.options != null) cmd.push.apply(cmd, this.config.options);
+
+  this.rubyPromise.then((function() {
+    if (isWindows) {
+      cmd = ['cmd', '/c', '"' + cmd[0] + '"'].concat(cmd.slice(1));
+      this.env.windowsVerbatimArguments = true;
+    }
+    var sass = spawn(cmd[0], cmd.slice(1), this.env);
+    sass.stdout.on('data', function(buffer) {
+      result += buffer.toString();
+    });
+    sass.stderr.on('data', function(buffer) {
+      if (error == null) error = '';
+      error += buffer.toString();
+    });
+    sass.on('close', function(code) {
+      callback(error, result);
+    });
+    if (sass.stdin.write(data)) {
+      sass.stdin.end();
+    } else {
+      sass.stdin.on('drain', function() {
+        sass.stdin.end();
+      });
+    }
+  }).bind(this));
+};
+
+SassCompiler.prototype.compile = function(data, path, callback) {
+  var fileUsesRuby = sassRe.test(path) || compassRe.test(data);
+  if (this.mode === 'ruby' || (!this.mode && fileUsesRuby)) {
+    this._rubyCompile(data, path, callback);
+  } else {
+    this._nativeCompile(data, path, callback);
+  }
+};
+
+module.exports = SassCompiler;

package.json

@@ -4,14 +4,14 @@
   "description": "Adds Sass support to brunch.",
   "author": "Paul Miller (http://paulmillr.com/)",
   "homepage": "https://github.com/brunch/sass-brunch",
+  "keywords": ["brunchplugin", "sass"],
   "repository": {
     "type": "git",
     "url": "git@github.com:brunch/sass-brunch.git"
   },
   "main": "./lib/index",
   "scripts": {
-    "prepublish": "rm -rf lib && coffee --bare --output lib/ src/",
-    "test": "node_modules/.bin/mocha --require test/common.js"
+    "test": "node_modules/.bin/mocha"
   },
   "dependencies": {
     "progeny": "~0.1.1"