Move RunCommand, and Info/Warning/Die into common pylib

lib/cros_build_lib.py

Index: lib/cros_build_lib.py
diff --git a/lib/cros_build_lib.py b/lib/cros_build_lib.py
new file mode 100644
index 0000000000000000000000000000000000000000..7b9b00da8664eb816448eb67689f985bbce575e4
--- /dev/null
+++ b/lib/cros_build_lib.py
@@ -0,0 +1,120 @@
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Common python commands used by various build scripts."""
+
+import subprocess
+import sys
+
+_STDOUT_IS_TTY = hasattr(sys.stdout, 'isatty') and sys.stdout.isatty()
+
+def RunCommand(cmd, print_cmd=True, error_ok=False, error_message=None,
+               exit_code=False, redirect_stdout=False, redirect_stderr=False,
+               cwd=None, input=None, enter_chroot=False):
+  """Runs a shell command.
+
+  Keyword arguments:
+    cmd - cmd to run.  Should be input to subprocess.POpen.  If a string,
+      converted to an array using split().
+    print_cmd -- prints the command before running it.
+    error_ok -- does not raise an exception on error.
+    error_message -- prints out this message when an error occurrs.
+    exit_code -- returns the return code of the shell command.
+    redirect_stdout -- returns the stdout.
+    redirect_stderr -- holds stderr output until input is communicated.
+    cwd -- the working directory to run this cmd.
+    input -- input to pipe into this command through stdin.
+    enter_chroot -- this command should be run from within the chroot.  If set,
+      cwd must point to the scripts directory.
+  Raises:
+    Exception:  Raises generic exception on error with optional error_message.
+  """
+  # Set default for variables.
+  stdout = None
+  stderr = None
+  stdin = None
+
+  # Modify defaults based on parameters.
+  if redirect_stdout:  stdout = subprocess.PIPE
+  if redirect_stderr:  stderr = subprocess.PIPE
+  if input:  stdin = subprocess.PIPE
+  if enter_chroot:  cmd = ['./enter_chroot.sh', '--'] + cmd
+
+  # Print out the command before running.
+  if print_cmd:
+    Info('RunCommand: %s' % ' '.join(cmd))
+
+  proc = subprocess.Popen(cmd, cwd=cwd, stdin=stdin,
+                          stdout=stdout, stderr=stderr)
+  (output, error) = proc.communicate(input)
+  if exit_code:
+    return proc.returncode
+
+  if not error_ok and proc.returncode:
+    raise Exception('Command "%s" failed.\n' % (' '.join(cmd)) +
+                    (error_message or error or output or ''))
+
+  return output
+
+
+class Color(object):
+  """Conditionally wraps text in ANSI color escape sequences."""
+  BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE = range(8)
+  BOLD = -1
+  COLOR_START = '\033[1;%dm'
+  BOLD_START = '\033[1m'
+  RESET = '\033[0m'
+
+  def __init__(self, enabled=True):
+    self._enabled = enabled
+
+  def Color(self, color, text):
+    """Returns text with conditionally added color escape sequences.
+
+    Keyword arguments:
+      color: Text color -- one of the color constants defined in this class.
+      text: The text to color.
+
+    Returns:
+      If self._enabled is False, returns the original text. If it's True,
+      returns text with color escape sequences based on the value of color.
+    """
+    if not self._enabled:
+      return text
+    if color == self.BOLD:
+      start = self.BOLD_START
+    else:
+      start = self.COLOR_START % (color + 30)
+    return start + text + self.RESET
+
+
+def Die(message):
+  """Emits a red error message and halts execution.
+
+  Keyword arguments:
+    message: The message to be emitted before exiting.
+  """
+  print >> sys.stderr, (
+      Color(_STDOUT_IS_TTY).Color(Color.RED, '\nERROR: ' + message))
+  sys.exit(1)
+
+
+def Warning(message):
+  """Emits a yellow warning message and continues execution.
+
+  Keyword arguments:
+    message: The message to be emitted.
+  """
+  print >> sys.stderr, (
+      Color(_STDOUT_IS_TTY).Color(Color.YELLOW, '\nWARNING: ' + message))
+
+
+def Info(message):
+  """Emits a blue informational message and continues execution.
+
+  Keyword arguments:
+    message: The message to be emitted.
+  """
+  print >> sys.stderr, (
+      Color(_STDOUT_IS_TTY).Color(Color.BLUE, '\nINFO: ' + message))