Adds transform option to api

README.md

@@ -97,6 +97,26 @@ asar.createPackage(src, dest, function() {
 
 Please note that there is currently *no* error handling provided!
 
+### Transform
+You can pass in a `transform` option, that is a function, which either returns
+nothing, or a `stream.Transform`. The latter will be used on files that will be
+in the `.asar` file to transform them (e.g. compress).
+
+```js
+var asar = require('asar');
+
+var src = 'some/path/';
+var dest = 'name.asar';
+
+function transform(filename) {
+  return new CustomTransformStream()
+}
+
+asar.createPackageWithOptions(src, dest, { transform: transform }, function() {
+  console.log('done.');
+})
+```
+
 ## Using with grunt
 
 There is also an unofficial grunt plugin to generate asar archives at [bwin/grunt-asar][grunt-asar].

package.json

@@ -28,7 +28,8 @@
     "glob": "^6.0.4",
     "minimatch": "^3.0.0",
     "mkdirp": "^0.5.0",
-    "mksnapshot": "^0.3.0"
+    "mksnapshot": "^0.3.0",
+    "tmp": "0.0.28"
   },
   "devDependencies": {
     "coffee-script": "^1.10.0",

src/asar.coffee

@@ -76,7 +76,7 @@ module.exports.createPackageFromFiles = (src, dest, filenames, metadata, options
   else
     filenamesSorted = filenames
 
-  for filename in filenamesSorted
+  handleFile = (filename, done) ->
     file = metadata[filename]
     unless file
       stat = fs.lstatSync filename
@@ -101,18 +101,31 @@ module.exports.createPackageFromFiles = (src, dest, filenames, metadata, options
           dirName = path.relative src, path.dirname(filename)
           shouldUnpack = isUnpackDir dirName, options.unpackDir
         files.push filename: filename, unpack: shouldUnpack
-        filesystem.insertFile filename, shouldUnpack, file.stat
+        filesystem.insertFile filename, shouldUnpack, file, options, done
+        return
       when 'link'
         filesystem.insertLink filename, file.stat
+    done()
 
-  mkdirp path.dirname(dest), (error) ->
-    return callback(error) if error
-    disk.writeFilesystem dest, filesystem, files, (error) ->
+  insertsDone = ->
+    mkdirp path.dirname(dest), (error) ->
       return callback(error) if error
-      if options.snapshot
-        createSnapshot src, dest, filenames, metadata, options, callback
-      else
-        callback null
+      disk.writeFilesystem dest, filesystem, files, metadata, (error) ->
+        return callback(error) if error
+        if options.snapshot
+          createSnapshot src, dest, filenames, metadata, options, callback
+        else
+          callback null
+
+  names = filenamesSorted.slice()
+
+  next = (name) ->
+    if !name then return insertsDone()
+
+    handleFile name, ->
+      next names.shift()
+
+  next names.shift()
 
 module.exports.statFile = (archive, filename, followLinks) ->
   filesystem = disk.readFilesystemSync archive

src/disk.coffee

@@ -15,7 +15,7 @@ copyFileToSync = (dest, src, filename) ->
   mkdirp.sync path.dirname(targetFile)
   fs.writeFileSync targetFile, content, mode: stats.mode
 
-writeFileListToStream = (dest, filesystem, out, list, callback) ->
+writeFileListToStream = (dest, filesystem, out, list, metadata, callback) ->
   if list.length is 0
     out.end()
     return callback null
@@ -28,15 +28,16 @@ writeFileListToStream = (dest, filesystem, out, list, callback) ->
       copyFileToSync "#{dest}.unpacked", filesystem.src, filename
     catch error
       return callback error
-    writeFileListToStream dest, filesystem, out, list.slice(1), callback
+    writeFileListToStream dest, filesystem, out, list.slice(1), metadata, callback
   else
-    stream = fs.createReadStream(file.filename)
+    tr = metadata[file.filename].transformed
+    stream = fs.createReadStream (if tr then tr.path else file.filename)
+    stream.pipe out, end: false
     stream.on 'error', callback
     stream.on 'end', ->
-      writeFileListToStream dest, filesystem, out, list.slice(1), callback
-    stream.pipe out, end: false
+      writeFileListToStream dest, filesystem, out, list.slice(1), metadata, callback
 
-module.exports.writeFilesystem = (dest, filesystem, files, callback) ->
+module.exports.writeFilesystem = (dest, filesystem, files, metadata, callback) ->
   try
     headerPickle = pickle.createEmpty()
     headerPickle.writeString JSON.stringify(filesystem.header)
@@ -52,7 +53,7 @@ module.exports.writeFilesystem = (dest, filesystem, files, callback) ->
   out.on 'error', callback
   out.write sizeBuf
   out.write headerBuf, ->
-    writeFileListToStream dest, filesystem, out, files, callback
+    writeFileListToStream dest, filesystem, out, files, metadata, callback
 
 module.exports.readArchiveHeaderSync = (archive) ->
   fd = fs.openSync archive, 'r'

src/filesystem.coffee

@@ -1,5 +1,6 @@
 fs = require 'fs'
 path = require 'path'
+tmp = require 'tmp'
 UINT64 = require('cuint').UINT64
 
 class Filesystem
@@ -28,23 +29,47 @@ class Filesystem
     node.unpacked = shouldUnpack if shouldUnpack
     node.files = {}
 
-  insertFile: (p, shouldUnpack, stat) ->
+  insertFile: (p, shouldUnpack, file, options, callback) ->
     dirNode = @searchNodeFromPath path.dirname(p)
     node = @searchNodeFromPath p
     if shouldUnpack or dirNode.unpacked
-      node.size = stat.size
+      node.size = file.stat.size
       node.unpacked = true
+      callback()
       return
 
-    # JavaScript can not precisely present integers >= UINT32_MAX.
-    if stat.size > 4294967295
-      throw new Error("#{p}: file size can not be larger than 4.2GB")
+    self = this
+    handler = ->
+      size = if file.transformed then file.transformed.stat.size else file.stat.size
 
-    node.size = stat.size
-    node.offset = @offset.toString()
-    if process.platform isnt 'win32' and stat.mode & 0o100
-      node.executable = true
-    @offset.add UINT64(stat.size)
+      # JavaScript can not precisely present integers >= UINT32_MAX.
+      if size > 4294967295
+        throw new Error("#{p}: file size can not be larger than 4.2GB")
+
+      node.size = size
+      node.offset = self.offset.toString()
+      if process.platform isnt 'win32' and file.stat.mode & 0o100
+        node.executable = true
+      self.offset.add UINT64(size)
+
+      callback()
+
+    tr = options.transform && options.transform(p)
+    if tr
+      tmp.file (err, path) ->
+        return handler() if err
+        out = fs.createWriteStream(path)
+        stream = fs.createReadStream p
+
+        stream.pipe(tr).pipe(out)
+        tr.on 'end', ->
+          file.transformed = {
+            path,
+            stat: fs.lstatSync path
+          }
+          handler()
+    else
+      handler()
 
   insertLink: (p, stat) ->
     link = path.relative fs.realpathSync(@src), fs.realpathSync(p)

test/api-spec.coffee

@@ -5,6 +5,7 @@ os = require 'os'
 asar = require '../lib/asar'
 compDirs = require './util/compareDirectories'
 compFiles = require './util/compareFiles'
+transform = require './util/transformStream'
 
 describe 'api', ->
   it 'should create archive from directory', (done) ->
@@ -17,6 +18,11 @@ describe 'api', ->
       done compFiles 'tmp/packthis-api.asar', 'test/expected/packthis.asar'
       return
     return
+  it 'should create archive from directory (with transformed files)', (done) ->
+    asar.createPackageWithOptions 'test/input/packthis/', 'tmp/packthis-api-transformed.asar', {transform}, (error) ->
+      done compFiles 'tmp/packthis-api-transformed.asar', 'test/expected/packthis-transformed.asar'
+      return
+    return
   it 'should list files/dirs in archive', ->
     actual = asar.listPackage('test/input/extractthis.asar').join('\n')
     expected = fs.readFileSync 'test/expected/extractthis-filelist.txt', 'utf8'

test/util/transformStream.coffee

@@ -0,0 +1,20 @@
+{ Transform } = require 'stream'
+{ basename } = require 'path'
+
+class Reverser extends Transform
+  constructor: ->
+    super()
+    @_data = ''
+
+  _transform: (buf, enc, cb) ->
+    @_data += buf
+    cb()
+
+  _flush: (cb) ->
+    txt = @_data.toString().split('').reverse().join('')
+    @push(txt)
+    cb()
+
+module.exports = (filename) ->
+  if basename(filename) is 'file0.txt'
+    return new Reverser()