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.
10 class FlagChanger(object):
11 """Changes the flags Chrome runs with.
13 There are two different use cases for this file:
14 * Flags are permanently set by calling Set().
15 * Flags can be temporarily set for a particular set of unit tests. These
16 tests should call Restore() to revert the flags to their original state
17 once the tests have completed.
20 def __init__(self, adb,
21 cmdline_file=constants.PACKAGE_INFO['chrome'].cmdline_file):
22 """Initializes the FlagChanger and records the original arguments.
25 adb: An instance of AndroidCommands.
26 cmdline_file: Path to the command line file on the device.
29 self._cmdline_file = cmdline_file
31 # Save the original flags.
32 self._orig_line = self._adb.GetFileContents(self._cmdline_file)
34 self._orig_line = self._orig_line[0].strip()
36 # Parse out the flags into a list to facilitate adding and removing flags.
37 self._current_flags = self._TokenizeFlags(self._orig_line)
40 """Returns list of current flags."""
41 return self._current_flags
44 """Replaces all flags on the current command line with the flags given.
47 flags: A list of flags to set, eg. ['--single-process'].
50 assert flags[0] != 'chrome'
52 self._current_flags = flags
53 self._UpdateCommandLineFile()
55 def AddFlags(self, flags):
56 """Appends flags to the command line if they aren't already there.
59 flags: A list of flags to add on, eg. ['--single-process'].
62 assert flags[0] != 'chrome'
64 # Avoid appending flags that are already present.
66 if flag not in self._current_flags:
67 self._current_flags.append(flag)
68 self._UpdateCommandLineFile()
70 def RemoveFlags(self, flags):
71 """Removes flags from the command line, if they exist.
74 flags: A list of flags to remove, eg. ['--single-process']. Note that we
75 expect a complete match when removing flags; if you want to remove
76 a switch with a value, you must use the exact string used to add
77 it in the first place.
80 assert flags[0] != 'chrome'
83 if flag in self._current_flags:
84 self._current_flags.remove(flag)
85 self._UpdateCommandLineFile()
88 """Restores the flags to their original state."""
89 self._current_flags = self._TokenizeFlags(self._orig_line)
90 self._UpdateCommandLineFile()
92 def _UpdateCommandLineFile(self):
93 """Writes out the command line to the file, or removes it if empty."""
94 logging.info('Current flags: %s', self._current_flags)
95 # Root is not required to write to /data/local/tmp/.
96 use_root = '/data/local/tmp/' not in self._cmdline_file
97 if self._current_flags:
98 # The first command line argument doesn't matter as we are not actually
99 # launching the chrome executable using this command line.
100 cmd_line = ' '.join(['_'] + self._current_flags)
102 self._adb.SetProtectedFileContents(self._cmdline_file, cmd_line)
103 file_contents = self._adb.GetProtectedFileContents(self._cmdline_file)
105 self._adb.SetFileContents(self._cmdline_file, cmd_line)
106 file_contents = self._adb.GetFileContents(self._cmdline_file)
107 assert len(file_contents) == 1 and file_contents[0] == cmd_line, (
108 'Failed to set the command line file at %s' % self._cmdline_file)
111 self._adb.RunShellCommandWithSU('rm ' + self._cmdline_file)
113 self._adb.RunShellCommand('rm ' + self._cmdline_file)
114 assert not self._adb.FileExistsOnDevice(self._cmdline_file), (
115 'Failed to remove the command line file at %s' % self._cmdline_file)
117 def _TokenizeFlags(self, line):
118 """Changes the string containing the command line into a list of flags.
120 Follows similar logic to CommandLine.java::tokenizeQuotedArguments:
121 * Flags are split using whitespace, unless the whitespace is within a
122 pair of quotation marks.
123 * Unlike the Java version, we keep the quotation marks around switch
124 values since we need them to re-create the file when new flags are
128 line: A string containing the entire command line. The first token is
129 assumed to be the program name.
136 within_quotations = False
138 # Move through the string character by character and build up each flag
140 for c in line.strip():
142 if len(current_flag) > 0 and current_flag[-1] == '\\':
143 # Last char was a backslash; pop it, and treat this " as a literal.
144 current_flag = current_flag[0:-1] + '"'
146 within_quotations = not within_quotations
148 elif not within_quotations and (c is ' ' or c is '\t'):
149 if current_flag is not "":
150 tokenized_flags.append(current_flag)
155 # Tack on the last flag.
157 if within_quotations:
158 logging.warn('Unterminated quoted argument: ' + line)
160 tokenized_flags.append(current_flag)
162 # Return everything but the program name.
163 return tokenized_flags[1:]