Prebuild LESS cache for common theme configurations

Gruntfile.coffee

@@ -45,6 +45,12 @@ module.exports = (grunt) ->
       dest: appDir
       ext: '.css'
 
+  prebuildLessConfig =
+    src: [
+      'static/**/*.less'
+      'vendor/bootstrap/less/bootstrap.less'
+    ]
+
   csonConfig =
     options:
       rootObject: true
@@ -60,10 +66,11 @@ module.exports = (grunt) ->
 
   for child in fs.readdirSync('node_modules') when child isnt '.bin'
     directory = path.join('node_modules', child)
-    {engines} = grunt.file.readJSON(path.join(directory, 'package.json'))
+    {engines, theme} = grunt.file.readJSON(path.join(directory, 'package.json'))
     if engines?.atom?
       coffeeConfig.glob_to_multiple.src.push("#{directory}/**/*.coffee")
       lessConfig.glob_to_multiple.src.push("#{directory}/**/*.less")
+      prebuildLessConfig.src.push("#{directory}/**/*.less") unless theme
       csonConfig.glob_to_multiple.src.push("#{directory}/**/*.cson")
 
   grunt.initConfig
@@ -75,6 +82,8 @@ module.exports = (grunt) ->
 
     less: lessConfig
 
+    'prebuild-less': prebuildLessConfig
+
     cson: csonConfig
 
     coffeelint:
@@ -172,7 +181,7 @@ module.exports = (grunt) ->
   grunt.loadNpmTasks('grunt-shell')
   grunt.loadTasks('tasks')
 
-  grunt.registerTask('compile', ['coffee', 'cson'])
+  grunt.registerTask('compile', ['coffee', 'prebuild-less', 'cson'])
   grunt.registerTask('lint', ['coffeelint', 'csslint', 'lesslint'])
   grunt.registerTask('test', ['shell:kill-atom', 'shell:test'])
   grunt.registerTask('ci', ['lint', 'update-atom-shell', 'build', 'set-development-version', 'test'])

src/less-compile-cache.coffee

@@ -1,6 +1,9 @@
+path = require 'path'
+
 _ = require 'underscore'
 LessCache = require 'less-cache'
 
+
 module.exports =
 class LessCompileCache
   _.extend @prototype, require('./subscriber')
@@ -8,10 +11,12 @@ class LessCompileCache
   @cacheDir: '/tmp/atom-compile-cache/less'
 
   constructor: ->
-    importPaths =
     @cache = new LessCache
       cacheDir: @constructor.cacheDir
       importPaths: @getImportPaths()
+      resourcePath: window.resourcePath
+      fallbackDir: path.join(window.resourcePath, 'less-compile-cache')
+
     @subscribe atom.themes, 'reloaded', => @cache.setImportPaths(@getImportPaths())
 
   getImportPaths: -> atom.themes.getImportPaths().concat(config.lessSearchPaths)

tasks/prebuild-less-task.coffee

@@ -0,0 +1,35 @@
+path = require 'path'
+
+LessCache = require 'less-cache'
+
+module.exports = (grunt) ->
+  grunt.registerMultiTask 'prebuild-less', 'Prebuild cached of compiled LESS files', ->
+    prebuiltConfigurations = [
+      ['atom-dark-ui', 'atom-dark-syntax']
+      ['atom-dark-ui', 'atom-light-syntax']
+      ['atom-light-ui', 'atom-light-syntax']
+      ['atom-light-ui', 'atom-dark-syntax']
+    ]
+
+    directory = path.join(grunt.config.get('atom.appDir'), 'less-compile-cache')
+
+    for configuration in prebuiltConfigurations
+      importPaths = [
+        path.resolve('static/variables')
+        path.resolve('static')
+        path.resolve('vendor')
+      ]
+      for theme in configuration
+        # TODO Using AtomPackage class once it runs outside of an Atom context
+        themePath = path.resolve('node_modules', theme, 'stylesheets')
+        importPaths.unshift(themePath) if grunt.file.isDir(themePath)
+
+      grunt.log.writeln("Building LESS cache for #{configuration.join(', ').yellow}")
+      lessCache = new LessCache
+        cacheDir: directory
+        resourcePath: path.resolve('.')
+        importPaths: importPaths
+
+      for file in @filesSrc
+        grunt.log.writeln("File #{file.cyan} created in cache.")
+        lessCache.readFileSync(file)