Try to better guess Visual Studio path when building Dart on Windows.

tools/utils.py

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # This file contains a set of utilities functions used by other Python-based
 # scripts.
 
 import commands
 import os
 import platform
@@ skipping 42 matching lines @@
 def GuessCpus():
   if os.path.exists("/proc/cpuinfo"):
     return int(commands.getoutput("grep -E '^processor' /proc/cpuinfo | wc -l"))
   if os.path.exists("/usr/bin/hostinfo"):
     return int(commands.getoutput('/usr/bin/hostinfo | grep "processors are logically available." | awk "{ print \$1 }"'))
   win_cpu_count = os.getenv("NUMBER_OF_PROCESSORS")
   if win_cpu_count:
     return int(win_cpu_count)
   return int(os.getenv("DART_NUMBER_OF_CORES", 2))
 
+# Try to guess Visual Studio location when buiding on Windows.
+def GuessVisualStudioPath():
+  defaultPath = 'C:\\Program Files (x86)\\Microsoft Visual Studio 10.0\\Common7'
+  '\\IDE'
+  if IsWindows():

[ahe, 2013/02/18 15:47:20]

if not IsWindows():
  return defaultPath

Then the rest doesn't need to be indented.

[aam-me, 2013/02/18 16:20:06]

Done.

+    import win32process
+    # Check if python process is 64-bit or if it's 32-bit running in 64-bit OS.
+    # We need to know whether host is 64-bit so that we are looking in right
+    # registry for Visual Studio path.
+    if sys.maxsize > 2**32 or win32process.IsWow64Process():
+      wow6432Node = "Wow6432Node\\"
+    else:
+      wow6432Node = ""
+
+    import _winreg
+    try:
+      key = _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE,
+                           "SOFTWARE\\" + wow6432Node + "Microsoft\\VisualStudio")

[ahe, 2013/02/18 15:47:20]

Long line. Also, I think our Python style guide prefer using % rather than
string concatenation with +. So this should be:

"SOFTWARE\\%sMicrosoft\\VisualStudio" % wow6432Node

[aam-me, 2013/02/18 16:20:06]

Done.

+    except WindowsError:

[ahe, 2013/02/18 15:47:20]

Please document why it is OK to ignore this error.

[aam-me, 2013/02/18 16:20:06]

Done.

+      return defaultPath
+
+    iSubkey = 0

[ahe, 2013/02/18 15:47:20]

What does this variable mean? The word "iSubkey" is a bit strange.

[aam-me, 2013/02/18 16:20:06]

This is subkey counter. Changed name.

+    while(True):

[ahe, 2013/02/18 15:47:20]

I don't think you need parentheses here in Python.

[aam-me, 2013/02/18 16:20:06]

Done.

+      try:
+        subkeyName = _winreg.EnumKey(key, iSubkey)
+      except WindowsError:
+        # Reached end of enumeration

[ahe, 2013/02/18 15:47:20]

Is there a way to check, or must you catch an exception?

[aam-me, 2013/02/18 16:20:06]

According to http://docs.python.org/2/library/_winreg.html#_winreg.EnumKey I
have to catch exception, unfortunately.

+        return defaultPath
+      match = re.match('^(\\d+\\.\\d+)$', subkeyName)
+      if not match is None:

[ahe, 2013/02/18 15:47:20]

if match:

[aam-me, 2013/02/18 16:20:06]

Done.

+        with _winreg.OpenKey(key, subkeyName) as subkey:
+          try:
+            (path, registrytype) = _winreg.QueryValueEx(subkey, 'InstallDir')
+            return path
+          except WindowsError:
+            # Can't find value under the key - continue to the next key
+            pass
+      iSubkey = iSubkey + 1
+
+    _winreg.CloseKey(key)

[ahe, 2013/02/18 15:47:20]

This is dead code as it comes after an "infinite" loop.

[aam-me, 2013/02/18 16:20:06]

Thanks. Wrapped it into try: finally: to close the key.

+  else:
+    return defaultPath
 
 # Returns true if we're running under Windows.
 def IsWindows():
   return GuessOS() == 'win32'
 
-
 # Reads a text file into an array of strings - one for each
 # line. Strips comments in the process.
 def ReadLinesFrom(name):
   result = []
   for line in open(name):
     if '#' in line:
       line = line[:line.find('#')]
     line = line.strip()
     if len(line) == 0:
       continue
@@ skipping 185 matching lines @@
     os.unlink(name)
   except OSError, e:
     PrintError("os.unlink() " + str(e))
 
 
 def Main(argv):
   print "GuessOS() -> ", GuessOS()
   print "GuessArchitecture() -> ", GuessArchitecture()
   print "GuessCpus() -> ", GuessCpus()
   print "IsWindows() -> ", IsWindows()
+  print "GuessVisualStudioPath() -> ", GuessVisualStudioPath()
 
 
 class Error(Exception):
   pass
 
 
 class ToolError(Exception):
   """Deprecated exception, use Error instead."""
 
   def __init__(self, value):
@@ skipping 37 matching lines @@
 
 def DartSdkBinary():
   tools_dir = os.path.dirname(os.path.realpath(__file__))
   dart_binary_prefix = os.path.join(tools_dir, '..', 'sdk' , 'bin')
   return os.path.join(dart_binary_prefix, 'dart')
 
 
 if __name__ == "__main__":
   import sys
   Main(sys.argv)