The Tor Browser: media/webrtc/trunk/build/android/pylib/flag

     1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.

     2 # Use of this source code is governed by a BSD-style license that can be

     3 # found in the LICENSE file.

     5 import constants

     6 import traceback

     7 import warnings

    10 # Location where chrome reads command line flags from

    11 CHROME_COMMAND_FILE = constants.TEST_EXECUTABLE_DIR + '/chrome-command-line'

    13 class FlagChanger(object):

    14   """Changes the flags Chrome runs with.

    16   There are two different use cases for this file:

    17   * Flags are permanently set by calling Set().

    18   * Flags can be temporarily set for a particular set of unit tests.  These

    19     tests should call Restore() to revert the flags to their original state

    20     once the tests have completed.

    21   """

    23   def __init__(self, android_cmd):

    24     self._android_cmd = android_cmd

    26     # Save the original flags.

    27     self._orig_line = self._android_cmd.GetFileContents(CHROME_COMMAND_FILE)

    28     if self._orig_line:

    29       self._orig_line = self._orig_line[0].strip()

    31     # Parse out the flags into a list to facilitate adding and removing flags.

    32     self._current_flags = self._TokenizeFlags(self._orig_line)

    34   def Get(self):

    35     """Returns list of current flags."""

    36     return self._current_flags

    38   def Set(self, flags):

    39     """Replaces all flags on the current command line with the flags given.

    41     Args:

    42       flags: A list of flags to set, eg. ['--single-process'].

    43     """

    44     if flags:

    45       assert flags[0] != 'chrome'

    47     self._current_flags = flags

    48     self._UpdateCommandLineFile()

    50   def AddFlags(self, flags):

    51     """Appends flags to the command line if they aren't already there.

    53     Args:

    54       flags: A list of flags to add on, eg. ['--single-process'].

    55     """

    56     if flags:

    57       assert flags[0] != 'chrome'

    59     # Avoid appending flags that are already present.

    60     for flag in flags:

    61       if flag not in self._current_flags:

    62         self._current_flags.append(flag)

    63     self._UpdateCommandLineFile()

    65   def RemoveFlags(self, flags):

    66     """Removes flags from the command line, if they exist.

    68     Args:

    69       flags: A list of flags to remove, eg. ['--single-process'].  Note that we

    70              expect a complete match when removing flags; if you want to remove

    71              a switch with a value, you must use the exact string used to add

    72              it in the first place.

    73     """

    74     if flags:

    75       assert flags[0] != 'chrome'

    77     for flag in flags:

    78       if flag in self._current_flags:

    79         self._current_flags.remove(flag)

    80     self._UpdateCommandLineFile()

    82   def Restore(self):

    83     """Restores the flags to their original state."""

    84     self._current_flags = self._TokenizeFlags(self._orig_line)

    85     self._UpdateCommandLineFile()

    87   def _UpdateCommandLineFile(self):

    88     """Writes out the command line to the file, or removes it if empty."""

    89     print "Current flags: ", self._current_flags

    91     if self._current_flags:

    92       self._android_cmd.SetFileContents(CHROME_COMMAND_FILE,

    93                                         'chrome ' +

    94                                         ' '.join(self._current_flags))

    95     else:

    96       self._android_cmd.RunShellCommand('rm ' + CHROME_COMMAND_FILE)

    98   def _TokenizeFlags(self, line):

    99     """Changes the string containing the command line into a list of flags.

   101     Follows similar logic to CommandLine.java::tokenizeQuotedArguments:

   102     * Flags are split using whitespace, unless the whitespace is within a

   103       pair of quotation marks.

   104     * Unlike the Java version, we keep the quotation marks around switch

   105       values since we need them to re-create the file when new flags are

   106       appended.

   108     Args:

   109       line: A string containing the entire command line.  The first token is

   110             assumed to be the program name.

   111     """

   112     if not line:

   113       return []

   115     tokenized_flags = []

   116     current_flag = ""

   117     within_quotations = False

   119     # Move through the string character by character and build up each flag

   120     # along the way.

   121     for c in line.strip():

   122       if c is '"':

   123         if len(current_flag) > 0 and current_flag[-1] == '\\':

   124           # Last char was a backslash; pop it, and treat this " as a literal.

   125           current_flag = current_flag[0:-1] + '"'

   126         else:

   127           within_quotations = not within_quotations

   128           current_flag += c

   129       elif not within_quotations and (c is ' ' or c is '\t'):

   130         if current_flag is not "":

   131           tokenized_flags.append(current_flag)

   132           current_flag = ""

   133       else:

   134         current_flag += c

   136     # Tack on the last flag.

   137     if not current_flag:

   138       if within_quotations:

   139         warnings.warn("Unterminated quoted string: " + current_flag)

   140     else:

   141       tokenized_flags.append(current_flag)

   143     # Return everything but the program name.

   144     return tokenized_flags[1:]

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