Create helper to buffer process lines

src/packages/symbols-view/lib/tag-generator.coffee

@@ -1,6 +1,7 @@
 Point = require 'point'
 ChildProcess = nodeRequire 'child_process'
 $ = require 'jquery'
+BufferedProcess = require 'buffered-process'
 
 module.exports =
 class TagGenerator
@@ -15,18 +16,15 @@ class TagGenerator
       null
 
   generate: ->
+    deferred = $.Deferred()
+    tags = []
     command = "#{require.resolve('ctags')}"
     args = ['--fields=+KS', '-nf', '-', @path]
-    ctags = ChildProcess.spawn(command, args)
-    deferred = $.Deferred()
-    output = ''
-    ctags.stdout.setEncoding('utf8')
-    ctags.stdout.on 'data', (data) ->
-      output += data
-    ctags.stdout.on 'close', =>
-      tags = []
-      for line in output.split('\n')
+    stdout = (lines) =>
+      for line in lines.split('\n')
         tag = @parseTagLine(line)
         tags.push(tag) if tag
+    exit = ->
       deferred.resolve(tags)
+    new BufferedProcess({command, args, stdout, exit})
     deferred

src/stdlib/buffered-process.coffee

@@ -0,0 +1,46 @@
+ChildProcess = nodeRequire 'child_process'
+
+module.exports =
+class BufferedProcess
+  constructor: (options={}) ->
+    process = ChildProcess.spawn(options.command, options.args)
+
+    stdoutClosed = true
+    stderrClosed = true
+    processExited = true
+    triggerExitCallback = ->
+      if stdoutClosed and stderrClosed and processExited
+        options.exit?()
+
+    if options.stdout
+      stdoutClosed = false
+      @bufferStream process.stdout, options.stdout, ->
+        stdoutClosed = true
+        triggerExitCallback()
+
+    if options.stderr
+      stderrClosed = false
+      @bufferStream process.stderr, options.stderr, ->
+        stderrClosed = true
+        triggerExitCallback()
+
+    if options.exit
+      processExited = false
+      process.on 'exit', ->
+        processExited = true
+        triggerExitCallback()
+
+  bufferStream: (stream, onLines, onDone) ->
+    stream.setEncoding('utf8')
+    buffered = ''
+
+    stream.on 'data', (data) ->
+      buffered += data
+      lastNewlineIndex = buffered.lastIndexOf('\n')
+      if lastNewlineIndex isnt -1
+        onLines(buffered.substring(0, lastNewlineIndex + 1))
+        buffered = buffered.substring(lastNewlineIndex + 1)
+
+    stream.on 'close', =>
+      onLines(buffered) if buffered.length > 0
+      onDone()