Provide importedFilePathsByRelativeImportPath to LessCache

script/lib/prebuild-less-cache.js

@@ -1,6 +1,7 @@
 'use strict'
 
 const fs = require('fs')
+const klawSync = require('klaw-sync')
 const glob = require('glob')
 const path = require('path')
 const LessCache = require('less-cache')
@@ -29,13 +30,17 @@ module.exports = function () {
   }
 
   CONFIG.snapshotAuxiliaryData.lessSourcesByRelativeFilePath = {}
-  function saveIntoSnapshotAuxiliaryData (absoluteFilePath, contents) {
+  function saveIntoSnapshotAuxiliaryData (absoluteFilePath, content) {
     const relativeFilePath = path.relative(CONFIG.intermediateAppPath, absoluteFilePath)
     if (!CONFIG.snapshotAuxiliaryData.lessSourcesByRelativeFilePath.hasOwnProperty(relativeFilePath)) {
-      CONFIG.snapshotAuxiliaryData.lessSourcesByRelativeFilePath[relativeFilePath] = contents
+      CONFIG.snapshotAuxiliaryData.lessSourcesByRelativeFilePath[relativeFilePath] = {
+        content: content,
+        digest: LessCache.digestForContent(content)
+      }
     }
   }
 
+  CONFIG.snapshotAuxiliaryData.importedFilePathsByRelativeImportPath = {}
   // Warm cache for every combination of the default UI and syntax themes,
   // because themes assign variables which may be used in any style sheet.
   for (let uiTheme of uiThemes) {
@@ -54,6 +59,19 @@ module.exports = function () {
         ]
       })
 
+      // Store file paths located at the import paths so that we can avoid scanning them at runtime.
+      for (const absoluteImportPath of lessCache.getImportPaths()) {
+        const relativeImportPath = path.relative(CONFIG.intermediateAppPath, absoluteImportPath)
+        if (!CONFIG.snapshotAuxiliaryData.importedFilePathsByRelativeImportPath.hasOwnProperty(relativeImportPath)) {
+          CONFIG.snapshotAuxiliaryData.importedFilePathsByRelativeImportPath[relativeImportPath] = []
+          for (const importedFile of klawSync(absoluteImportPath, {nodir: true})) {
+            CONFIG.snapshotAuxiliaryData.importedFilePathsByRelativeImportPath[relativeImportPath].push(
+              path.relative(CONFIG.intermediateAppPath, importedFile.path)
+            )
+          }
+        }
+      }
+
       function cacheCompiledCSS(lessFilePath, importFallbackVariables) {
         let lessSource = fs.readFileSync(lessFilePath, 'utf8')
         if (importFallbackVariables) {

script/package.json

@@ -15,6 +15,7 @@
     "fs-extra": "0.30.0",
     "glob": "7.0.3",
     "joanna": "0.0.8",
+    "klaw-sync": "^1.1.2",
     "legal-eagle": "0.14.0",
     "lodash.template": "4.4.0",
     "minidump": "0.9.0",

src/less-compile-cache.coffee

@@ -6,7 +6,7 @@ module.exports =
 class LessCompileCache
   @cacheDir: path.join(process.env.ATOM_HOME, 'compile-cache', 'less')
 
-  constructor: ({resourcePath, importPaths, lessSourcesByRelativeFilePath}) ->
+  constructor: ({resourcePath, importPaths, lessSourcesByRelativeFilePath, importedFilePathsByRelativeImportPath}) ->
     @lessSearchPaths = [
       path.join(resourcePath, 'static', 'variables')
       path.join(resourcePath, 'static')
@@ -17,12 +17,14 @@ class LessCompileCache
     else
       importPaths = @lessSearchPaths
 
-    @cache = new LessCache
-      cacheDir: @constructor.cacheDir
-      importPaths: importPaths
-      resourcePath: resourcePath
-      lessSourcesByRelativeFilePath: lessSourcesByRelativeFilePath
+    @cache = new LessCache({
+      importPaths,
+      resourcePath,
+      lessSourcesByRelativeFilePath,
+      importedFilePathsByRelativeImportPath,
+      cacheDir: @constructor.cacheDir,
       fallbackDir: path.join(resourcePath, 'less-compile-cache')
+    })
 
   setImportPaths: (importPaths=[]) ->
     @cache.setImportPaths(importPaths.concat(@lessSearchPaths))
@@ -30,5 +32,5 @@ class LessCompileCache
   read: (stylesheetPath) ->
     @cache.readFileSync(stylesheetPath)
 
-  cssForFile: (stylesheetPath, lessContent) ->
-    @cache.cssForFile(stylesheetPath, lessContent)
+  cssForFile: (stylesheetPath, lessContent, digest) ->
+    @cache.cssForFile(stylesheetPath, lessContent, digest)

src/theme-manager.coffee

@@ -21,8 +21,10 @@ class ThemeManager
     @lessSourcesByRelativeFilePath = null
     if typeof snapshotAuxiliaryData is 'undefined'
       @lessSourcesByRelativeFilePath = {}
+      @importedFilePathsByRelativeImportPath = {}
     else
       @lessSourcesByRelativeFilePath = snapshotAuxiliaryData.lessSourcesByRelativeFilePath
+      @importedFilePathsByRelativeImportPath = snapshotAuxiliaryData.importedFilePathsByRelativeImportPath
 
   initialize: ({@resourcePath, @configDirPath, @safeMode}) ->
 
@@ -202,7 +204,12 @@ class ThemeManager
   loadLessStylesheet: (lessStylesheetPath, importFallbackVariables=false) ->
     unless @lessCache?
       LessCompileCache = require './less-compile-cache'
-      @lessCache = new LessCompileCache({@resourcePath, @lessSourcesByRelativeFilePath, importPaths: @getImportPaths()})
+      @lessCache = new LessCompileCache({
+        @resourcePath,
+        @lessSourcesByRelativeFilePath,
+        @importedFilePathsByRelativeImportPath,
+        importPaths: @getImportPaths()
+      })
 
     try
       if importFallbackVariables
@@ -211,8 +218,15 @@ class ThemeManager
         @import "variables/syntax-variables";
         """
         relativeFilePath = path.relative(@resourcePath, lessStylesheetPath)
-        less = @lessSourcesByRelativeFilePath[relativeFilePath] ? fs.readFileSync(lessStylesheetPath, 'utf8')
-        @lessCache.cssForFile(lessStylesheetPath, [baseVarImports, less].join('\n'))
+        lessSource = @lessSourcesByRelativeFilePath[relativeFilePath]
+        if lessSource?
+          content = lessSource.content
+          digest = lessSource.digest
+        else
+          content = baseVarImports + '\n' + fs.readFileSync(lessStylesheetPath, 'utf8')
+          digest = null
+
+        @lessCache.cssForFile(lessStylesheetPath, content, digest)
       else
         @lessCache.read(lessStylesheetPath)
     catch error