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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. | |
4 | |
5 import traceback | |
6 import warnings | |
7 | |
8 | |
9 # Location where chrome reads command line flags from | |
10 CHROME_COMMAND_FILE = '/data/local/tmp/chrome-command-line' | |
11 | |
12 class FlagChanger(object): | |
13 """Changes the flags Chrome runs with. | |
14 | |
15 There are two different use cases for this file: | |
16 * Flags are permanently set by calling Set(). | |
17 * Flags can be temporarily set for a particular set of unit tests. These | |
18 tests should call Restore() to revert the flags to their original state | |
19 once the tests have completed. | |
20 """ | |
21 | |
22 def __init__(self, android_cmd): | |
23 self._android_cmd = android_cmd | |
24 | |
25 # Save the original flags. | |
26 self._orig_line = self._android_cmd.GetFileContents(CHROME_COMMAND_FILE) | |
27 if self._orig_line: | |
28 self._orig_line = self._orig_line[0].strip() | |
29 | |
30 # Parse out the flags into a list to facilitate adding and removing flags. | |
31 self._current_flags = self._TokenizeFlags(self._orig_line) | |
32 | |
33 def Get(self): | |
34 """Returns list of current flags.""" | |
35 return self._current_flags | |
36 | |
37 def Set(self, flags): | |
38 """Replaces all flags on the current command line with the flags given. | |
39 | |
40 Args: | |
41 flags: A list of flags to set, eg. ['--single-process']. | |
42 """ | |
43 if flags: | |
44 assert flags[0] != 'chrome' | |
45 | |
46 self._current_flags = flags | |
47 self._UpdateCommandLineFile() | |
48 | |
49 def AddFlags(self, flags): | |
50 """Appends flags to the command line if they aren't already there. | |
51 | |
52 Args: | |
53 flags: A list of flags to add on, eg. ['--single-process']. | |
54 """ | |
55 if flags: | |
56 assert flags[0] != 'chrome' | |
57 | |
58 # Avoid appending flags that are already present. | |
59 for flag in flags: | |
60 if flag not in self._current_flags: | |
61 self._current_flags.append(flag) | |
62 self._UpdateCommandLineFile() | |
63 | |
64 def RemoveFlags(self, flags): | |
65 """Removes flags from the command line, if they exist. | |
66 | |
67 Args: | |
68 flags: A list of flags to remove, eg. ['--single-process']. Note that we | |
69 expect a complete match when removing flags; if you want to remove | |
70 a switch with a value, you must use the exact string used to add | |
71 it in the first place. | |
72 """ | |
73 if flags: | |
74 assert flags[0] != 'chrome' | |
75 | |
76 for flag in flags: | |
77 if flag in self._current_flags: | |
78 self._current_flags.remove(flag) | |
79 self._UpdateCommandLineFile() | |
80 | |
81 def Restore(self): | |
82 """Restores the flags to their original state.""" | |
83 self._current_flags = self._TokenizeFlags(self._orig_line) | |
84 self._UpdateCommandLineFile() | |
85 | |
86 def _UpdateCommandLineFile(self): | |
87 """Writes out the command line to the file, or removes it if empty.""" | |
88 print "Current flags: ", self._current_flags | |
89 | |
90 if self._current_flags: | |
91 self._android_cmd.SetFileContents(CHROME_COMMAND_FILE, | |
92 'chrome ' + | |
93 ' '.join(self._current_flags)) | |
94 else: | |
95 self._android_cmd.RunShellCommand('rm ' + CHROME_COMMAND_FILE) | |
96 | |
97 def _TokenizeFlags(self, line): | |
98 """Changes the string containing the command line into a list of flags. | |
99 | |
100 Follows similar logic to CommandLine.java::tokenizeQuotedArguments: | |
101 * Flags are split using whitespace, unless the whitespace is within a | |
102 pair of quotation marks. | |
103 * Unlike the Java version, we keep the quotation marks around switch | |
104 values since we need them to re-create the file when new flags are | |
105 appended. | |
106 | |
107 Args: | |
108 line: A string containing the entire command line. The first token is | |
109 assumed to be the program name. | |
110 """ | |
111 if not line: | |
112 return [] | |
113 | |
114 tokenized_flags = [] | |
115 current_flag = "" | |
116 within_quotations = False | |
117 | |
118 # Move through the string character by character and build up each flag | |
119 # along the way. | |
120 for c in line.strip(): | |
121 if c is '"': | |
122 if len(current_flag) > 0 and current_flag[-1] == '\\': | |
123 # Last char was a backslash; pop it, and treat this " as a literal. | |
124 current_flag = current_flag[0:-1] + '"' | |
125 else: | |
126 within_quotations = not within_quotations | |
127 current_flag += c | |
128 elif not within_quotations and (c is ' ' or c is '\t'): | |
129 if current_flag is not "": | |
130 tokenized_flags.append(current_flag) | |
131 current_flag = "" | |
132 else: | |
133 current_flag += c | |
134 | |
135 # Tack on the last flag. | |
136 if not current_flag: | |
137 if within_quotations: | |
138 warnings.warn("Unterminated quoted string: " + current_flag) | |
139 else: | |
140 tokenized_flags.append(current_flag) | |
141 | |
142 # Return everything but the program name. | |
143 return tokenized_flags[1:] | |
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