From ad448184b4eefb647249209a75a4cf981be7fa60 Mon Sep 17 00:00:00 2001
From: Michelle Tilley <binarymuse@github.com>
Date: Sat, 29 Oct 2016 14:30:24 -0700
Subject: [PATCH] First pass at per-package transpilation

---
 src/compile-cache.js                  |  18 +++-
 src/package-transpilation-registry.js | 122 ++++++++++++++++++++++++++
 src/package.coffee                    |  15 ++++
 3 files changed, 152 insertions(+), 3 deletions(-)
 create mode 100644 src/package-transpilation-registry.js

diff --git a/src/compile-cache.js b/src/compile-cache.js
index ad1bd0a85..702b2659f 100644
--- a/src/compile-cache.js
+++ b/src/compile-cache.js
@@ -7,12 +7,24 @@
 
 var path = require('path')
 var fs = require('fs-plus')
+
+var PackageTranspilationRegistry = require('./package-transpilation-registry')
 var CSON = null
 
+var packageTranspilationRegistry = new PackageTranspilationRegistry()
+
 var COMPILERS = {
-  '.js': require('./babel'),
-  '.ts': require('./typescript'),
-  '.coffee': require('./coffee-script')
+  '.js': packageTranspilationRegistry.wrapTranspiler(require('./babel')),
+  '.ts': packageTranspilationRegistry.wrapTranspiler(require('./typescript')),
+  '.coffee': packageTranspilationRegistry.wrapTranspiler(require('./coffee-script'))
+}
+
+exports.addTranspilerConfigForPath = function (packagePath, config) {
+  packageTranspilationRegistry.addTranspilerConfigForPath(packagePath, config)
+}
+
+exports.removeTranspilerConfigForPath = function (packagePath) {
+  packageTranspilationRegistry.removeTranspilerConfigForPath(packagePath)
 }
 
 var cacheStats = {}
diff --git a/src/package-transpilation-registry.js b/src/package-transpilation-registry.js
new file mode 100644
index 000000000..caf83961e
--- /dev/null
+++ b/src/package-transpilation-registry.js
@@ -0,0 +1,122 @@
+var crypto = require('crypto')
+var fs = require('fs')
+var path = require('path')
+
+var Resolve = null
+
+function PackageTranspilationRegistry () {
+  this.configByPackagePath = {}
+  this.configByFilePath = {}
+  this.transpilerPaths = {}
+  this.transpilerHashes = {}
+}
+
+PackageTranspilationRegistry.prototype.addTranspilerConfigForPath = function (packagePath, config) {
+  packagePath = fs.realpathSync(packagePath)
+  this.configByPackagePath[packagePath] = Object.assign({}, config, {
+    path: packagePath
+  })
+}
+
+PackageTranspilationRegistry.prototype.removeTranspilerConfigForPath = function (packagePath) {
+  packagePath = fs.realpathSync(packagePath)
+  delete this.configByPackagePath[path]
+}
+
+// Wraps the transpiler in an object with the same interface
+// that falls back to the original transpiler implementation if and
+// only if a package hasn't registered its desire to transpile its own source.
+PackageTranspilationRegistry.prototype.wrapTranspiler = function (transpiler) {
+  var self = this
+  return {
+    getCachePath: function (sourceCode, filePath) {
+      var config = self.getPackageTranspilerConfigForFilePath(filePath)
+      if (config) {
+        return self.getCachePath(sourceCode, filePath, config)
+      }
+
+      return transpiler.getCachePath(sourceCode, filePath)
+    },
+
+    compile: function (sourceCode, filePath) {
+      var config = self.getPackageTranspilerConfigForFilePath(filePath)
+      if (config) {
+        return self.transpileWithPackageTranspiler(sourceCode, filePath, config)
+      }
+
+      return transpiler.compile(sourceCode, filePath)
+    },
+
+    shouldCompile: function (sourceCode, filePath) {
+      if (self.transpilerPaths[filePath]) {
+        return false
+      }
+      var config = self.getPackageTranspilerConfigForFilePath(filePath)
+      if (config) {
+        return true
+      }
+
+      return transpiler.shouldCompile(sourceCode, filePath)
+    }
+  }
+}
+
+PackageTranspilationRegistry.prototype.getPackageTranspilerConfigForFilePath = function (filePath) {
+  if (this.configByFilePath[filePath] !== undefined) return this.configByFilePath[filePath]
+
+  var config = null
+  var thisPath = filePath
+  var lastPath = null
+  // Iterate parents from the file path to the root, checking at each level
+  // to see if a package manages transpilation for that directory.
+  // This means searching for a config for `/path/to/file/here.js` only
+  // only iterates four times, even if there are hundreds of configs registered.
+  while (thisPath !== lastPath) { // until we reach the root
+    if (config = this.configByPackagePath[thisPath]) {
+      this.configByFilePath[filePath] = config
+      return config
+    }
+
+    lastPath = thisPath
+    thisPath = path.resolve(thisPath, '..')
+  }
+
+  this.configByFilePath[filePath] = null
+  return null
+}
+
+PackageTranspilationRegistry.prototype.getCachePath = function (sourceCode, filePath, config) {
+  var transpilerPath = path.join(config.path, config.transpiler)
+  var transpilerSource = config._transpilerSource || fs.readFileSync(transpilerPath, 'utf8')
+  config._transpilerSource = transpilerSource
+  return path.join(
+    "package-transpile",
+    crypto
+      .createHash('sha1')
+      .update(transpilerSource, 'utf8')
+      .update(sourceCode, 'utf8')
+      .digest('hex')
+  )
+}
+
+PackageTranspilationRegistry.prototype.transpileWithPackageTranspiler = function (sourceCode, filePath) {
+  var config = this.configByFilePath[filePath]
+
+  Resolve = Resolve || require('resolve')
+  var transpilerPath = Resolve.sync(config.transpiler, {basedir: config.path, extensions: Object.keys(require.extensions)})
+  if (transpilerPath) {
+    this.transpilerPaths[transpilerPath] = true
+    var transpiler = require(transpilerPath)
+    var result = transpiler.compile(sourceCode, filePath)
+    if (result === undefined) {
+      return sourceCode
+    } else {
+      return result
+    }
+  } else {
+    var err = new Error("Could not find transpiler '" + config.transpiler + "' from '" + config.path + "'")
+    console.error(err)
+  }
+}
+
+module.exports = PackageTranspilationRegistry
diff --git a/src/package.coffee b/src/package.coffee
index 323dfa8d2..10764460f 100644
--- a/src/package.coffee
+++ b/src/package.coffee
@@ -6,6 +6,7 @@ CSON = require 'season'
 fs = require 'fs-plus'
 {Emitter, CompositeDisposable} = require 'event-kit'
 
+CompileCache = require './compile-cache'
 ModuleCache = require './module-cache'
 ScopedProperties = require './scoped-properties'
 BufferedProcess = require './buffered-process'
@@ -86,6 +87,7 @@ class Package
         @loadStylesheets()
         @registerDeserializerMethods()
         @activateCoreStartupServices()
+        @registerTranspilerConfig()
         @configSchemaRegisteredOnLoad = @registerConfigSchemaFromMetadata()
         @settingsPromise = @loadSettings()
         if @shouldRequireMainModuleOnLoad() and not @mainModule?
@@ -94,6 +96,9 @@ class Package
         @handleError("Failed to load the #{@name} package", error)
     this
 
+  unload: ->
+    @unregisterTranspilerConfig()
+
   shouldRequireMainModuleOnLoad: ->
     not (
       @metadata.deserializers? or
@@ -247,6 +252,16 @@ class Package
           @activationDisposables.add @packageManager.serviceHub.consume(name, version, @mainModule[methodName].bind(@mainModule))
     return
 
+  registerTranspilerConfig: ->
+    if @metadata.atomTranspilers
+      for transpiler in @metadata.atomTranspilers
+        CompileCache.addTranspilerConfigForPath(@path, transpiler)
+
+  unregisterTranspilerConfig: ->
+    if @metadata.atomTranspilers
+      for transpiler in @metadata.atomTranspilers
+        CompileCache.removeTranspilerConfigForPath(@path)
+
   loadKeymaps: ->
     if @bundledPackage and @packageManager.packagesCache[@name]?
       @keymaps = (["#{@packageManager.resourcePath}#{path.sep}#{keymapPath}", keymapObject] for keymapPath, keymapObject of @packageManager.packagesCache[@name].keymaps)