Fix coloring madness in depot_tools.

setup_color.py

+#!/usr/bin/env python
+# Copyright (c) 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import sys
+from third_party import colorama
+
+IS_TTY = None
+OUT_TYPE = 'unknown'
+
+def init():
+  # should_wrap instructs colorama to wrap stdout/stderr with an ASNI colorcode
+  # interpreter that converts them to SetConsoleTextAttribute calls. This only
+  # should be True in cases where we're connected to cmd.exe's console. Setting
+  # this to True on non-windows systems has no effect.
+  should_wrap = False
+  global IS_TTY, OUT_TYPE
+  IS_TTY = sys.stdout.isatty()
+  if IS_TTY:
+    # Yay! We detected a console in the normal way. It doesn't really matter
+    # if it's windows or not, we win.
+    OUT_TYPE = 'console'
+    should_wrap = True
+  elif sys.platform.startswith('win'):
+    # assume this is some sort of file
+    OUT_TYPE = 'file (win)'
+
+    import msvcrt
+    import ctypes
+    h = msvcrt.get_osfhandle(sys.stdout.fileno())
+    # h is the win32 HANDLE for stdout.
+    ftype = ctypes.windll.kernel32.GetFileType(h)
+    if ftype == 2: # FILE_TYPE_CHAR
+      # This is a normal cmd console, but we'll only get here if we're running
+      # inside a `git command` which is actually git->bash->command. Not sure
+      # why isatty doesn't detect this case.
+      OUT_TYPE = 'console (cmd via msys)'
+      IS_TTY = True
+      should_wrap = True
+    elif ftype == 3: # FILE_TYPE_PIPE
+      OUT_TYPE = 'pipe (win)'
+      # This is some kind of pipe on windows. This could either be a real pipe
+      # or this could be msys using a pipe to emulate a pty. We use the same
+      # algorithm that msys-git uses to determine if it's connected to a pty or
+      # not.
+
+      # This function and the structures are defined in the MSDN documentation
+      # using the same names.
+      def NT_SUCCESS(status):
+        # The first two bits of status are the severity. The success
+        # severities are 0 and 1, and the !success severities are 2 and 3.
+        # Therefore since ctypes interprets the default restype of the call
+        # to be an 'C int' (which is guaranteed to be signed 32 bits), All
+        # success codes are positive, and all !success codes are negative.
+        return status >= 0
+
+      class UNICODE_STRING(ctypes.Structure):
+        _fields_ = [('Length', ctypes.c_ushort),
+                    ('MaximumLength', ctypes.c_ushort),
+                    ('Buffer', ctypes.c_wchar_p)]
+
+      class OBJECT_NAME_INFORMATION(ctypes.Structure):
+        _fields_ = [('Name', UNICODE_STRING),
+                    ('NameBuffer', ctypes.c_wchar_p)]
+
+      buf = ctypes.create_string_buffer('\0', 1024)
+      # Ask NT what the name of the object our stdout HANDLE is. It would be
+      # possible to use GetFileInformationByHandleEx, but it's only available
+      # on Vista+. If you're reading this in 2017 or later, feel free to
+      # refactor this out.
+      #
+      # The '1' here is ObjectNameInformation
+      if NT_SUCCESS(ctypes.windll.ntdll.NtQueryObject(h, 1, buf, len(buf)-2,
+                    None)):
+        out = OBJECT_NAME_INFORMATION.from_buffer(buf)
+        name = out.Name.Buffer.split('\\')[-1]
+        IS_TTY = name.startswith('msys-') and '-pty' in name
+        if IS_TTY:
+          OUT_TYPE = 'bash (msys)'
+    else:
+      # A normal file, or an unknown file type.
+      pass
+  else:
+    # This is non-windows, so we trust isatty.
+    OUT_TYPE = 'pipe or file'
+
+  colorama.init(wrap=should_wrap)
+
+if __name__ == '__main__':
+  init()
+  print 'IS_TTY:', IS_TTY
+  print 'OUT_TYPE:', OUT_TYPE