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