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// This class works with command lines: building and parsing.
6// Arguments with prefixes ('--', '-', and on Windows, '/') are switches.
7// Switches will precede all other arguments without switch prefixes.
8// Switches can optionally have values, delimited by '=', e.g., "-switch=value".
9// An argument of "--" will terminate switch parsing during initialization,
10// interpreting subsequent tokens as non-switch arguments, regardless of prefix.
11
12// There is a singleton read-only CommandLine that represents the command line
13// that the current process was started with.  It must be initialized in main().
14
15#ifndef BASE_COMMAND_LINE_H_
16#define BASE_COMMAND_LINE_H_
17
18#include <stddef.h>
19#include <map>
20#include <string>
21#include <vector>
22
23#include "base/base_export.h"
24#include "base/strings/string16.h"
25#include "base/strings/string_piece.h"
26#include "build/build_config.h"
27
28namespace base {
29
30class FilePath;
31
32class BASE_EXPORT CommandLine {
33 public:
34#if defined(OS_WIN)
35  // The native command line string type.
36  typedef base::string16 StringType;
37#elif defined(OS_POSIX)
38  typedef std::string StringType;
39#endif
40
41  typedef StringType::value_type CharType;
42  typedef std::vector<StringType> StringVector;
43  typedef std::map<std::string, StringType> SwitchMap;
44  typedef std::map<base::StringPiece, const StringType*> StringPieceSwitchMap;
45
46  // A constructor for CommandLines that only carry switches and arguments.
47  enum NoProgram { NO_PROGRAM };
48  explicit CommandLine(NoProgram no_program);
49
50  // Construct a new command line with |program| as argv[0].
51  explicit CommandLine(const FilePath& program);
52
53  // Construct a new command line from an argument list.
54  CommandLine(int argc, const CharType* const* argv);
55  explicit CommandLine(const StringVector& argv);
56
57  // Override copy and assign to ensure |switches_by_stringpiece_| is valid.
58  CommandLine(const CommandLine& other);
59  CommandLine& operator=(const CommandLine& other);
60
61  ~CommandLine();
62
63#if defined(OS_WIN)
64  // By default this class will treat command-line arguments beginning with
65  // slashes as switches on Windows, but not other platforms.
66  //
67  // If this behavior is inappropriate for your application, you can call this
68  // function BEFORE initializing the current process' global command line
69  // object and the behavior will be the same as Posix systems (only hyphens
70  // begin switches, everything else will be an arg).
71  static void set_slash_is_not_a_switch();
72#endif
73
74  // Initialize the current process CommandLine singleton. On Windows, ignores
75  // its arguments (we instead parse GetCommandLineW() directly) because we
76  // don't trust the CRT's parsing of the command line, but it still must be
77  // called to set up the command line. Returns false if initialization has
78  // already occurred, and true otherwise. Only the caller receiving a 'true'
79  // return value should take responsibility for calling Reset.
80  static bool Init(int argc, const char* const* argv);
81
82  // Destroys the current process CommandLine singleton. This is necessary if
83  // you want to reset the base library to its initial state (for example, in an
84  // outer library that needs to be able to terminate, and be re-initialized).
85  // If Init is called only once, as in main(), Reset() is not necessary.
86  static void Reset();
87
88  // Get the singleton CommandLine representing the current process's
89  // command line. Note: returned value is mutable, but not thread safe;
90  // only mutate if you know what you're doing!
91  static CommandLine* ForCurrentProcess();
92
93  // Returns true if the CommandLine has been initialized for the given process.
94  static bool InitializedForCurrentProcess();
95
96#if defined(OS_WIN)
97  static CommandLine FromString(const base::string16& command_line);
98#endif
99
100  // Initialize from an argv vector.
101  void InitFromArgv(int argc, const CharType* const* argv);
102  void InitFromArgv(const StringVector& argv);
103
104  // Constructs and returns the represented command line string.
105  // CAUTION! This should be avoided on POSIX because quoting behavior is
106  // unclear.
107  StringType GetCommandLineString() const {
108    return GetCommandLineStringInternal(false);
109  }
110
111#if defined(OS_WIN)
112  // Constructs and returns the represented command line string. Assumes the
113  // command line contains placeholders (eg, %1) and quotes any program or
114  // argument with a '%' in it. This should be avoided unless the placeholder is
115  // required by an external interface (eg, the Windows registry), because it is
116  // not generally safe to replace it with an arbitrary string. If possible,
117  // placeholders should be replaced *before* converting the command line to a
118  // string.
119  StringType GetCommandLineStringWithPlaceholders() const {
120    return GetCommandLineStringInternal(true);
121  }
122#endif
123
124  // Constructs and returns the represented arguments string.
125  // CAUTION! This should be avoided on POSIX because quoting behavior is
126  // unclear.
127  StringType GetArgumentsString() const {
128    return GetArgumentsStringInternal(false);
129  }
130
131#if defined(OS_WIN)
132  // Constructs and returns the represented arguments string. Assumes the
133  // command line contains placeholders (eg, %1) and quotes any argument with a
134  // '%' in it. This should be avoided unless the placeholder is required by an
135  // external interface (eg, the Windows registry), because it is not generally
136  // safe to replace it with an arbitrary string. If possible, placeholders
137  // should be replaced *before* converting the arguments to a string.
138  StringType GetArgumentsStringWithPlaceholders() const {
139    return GetArgumentsStringInternal(true);
140  }
141#endif
142
143  // Returns the original command line string as a vector of strings.
144  const StringVector& argv() const { return argv_; }
145
146  // Get and Set the program part of the command line string (the first item).
147  FilePath GetProgram() const;
148  void SetProgram(const FilePath& program);
149
150  // Returns true if this command line contains the given switch.
151  // Switch names must be lowercase.
152  // The second override provides an optimized version to avoid inlining codegen
153  // at every callsite to find the length of the constant and construct a
154  // StringPiece.
155  bool HasSwitch(const base::StringPiece& switch_string) const;
156  bool HasSwitch(const char switch_constant[]) const;
157
158  // Returns the value associated with the given switch. If the switch has no
159  // value or isn't present, this method returns the empty string.
160  // Switch names must be lowercase.
161  std::string GetSwitchValueASCII(const base::StringPiece& switch_string) const;
162  FilePath GetSwitchValuePath(const base::StringPiece& switch_string) const;
163  StringType GetSwitchValueNative(const base::StringPiece& switch_string) const;
164
165  // Get a copy of all switches, along with their values.
166  const SwitchMap& GetSwitches() const { return switches_; }
167
168  // Append a switch [with optional value] to the command line.
169  // Note: Switches will precede arguments regardless of appending order.
170  void AppendSwitch(const std::string& switch_string);
171  void AppendSwitchPath(const std::string& switch_string,
172                        const FilePath& path);
173  void AppendSwitchNative(const std::string& switch_string,
174                          const StringType& value);
175  void AppendSwitchASCII(const std::string& switch_string,
176                         const std::string& value);
177
178  // Copy a set of switches (and any values) from another command line.
179  // Commonly used when launching a subprocess.
180  void CopySwitchesFrom(const CommandLine& source,
181                        const char* const switches[],
182                        size_t count);
183
184  // Get the remaining arguments to the command.
185  StringVector GetArgs() const;
186
187  // Append an argument to the command line. Note that the argument is quoted
188  // properly such that it is interpreted as one argument to the target command.
189  // AppendArg is primarily for ASCII; non-ASCII input is interpreted as UTF-8.
190  // Note: Switches will precede arguments regardless of appending order.
191  void AppendArg(const std::string& value);
192  void AppendArgPath(const FilePath& value);
193  void AppendArgNative(const StringType& value);
194
195  // Append the switches and arguments from another command line to this one.
196  // If |include_program| is true, include |other|'s program as well.
197  void AppendArguments(const CommandLine& other, bool include_program);
198
199  // Insert a command before the current command.
200  // Common for debuggers, like "valgrind" or "gdb --args".
201  void PrependWrapper(const StringType& wrapper);
202
203#if defined(OS_WIN)
204  // Initialize by parsing the given command line string.
205  // The program name is assumed to be the first item in the string.
206  void ParseFromString(const base::string16& command_line);
207#endif
208
209 private:
210  // Disallow default constructor; a program name must be explicitly specified.
211  CommandLine();
212  // Allow the copy constructor. A common pattern is to copy of the current
213  // process's command line and then add some flags to it. For example:
214  //   CommandLine cl(*CommandLine::ForCurrentProcess());
215  //   cl.AppendSwitch(...);
216
217  // Internal version of GetCommandLineString. If |quote_placeholders| is true,
218  // also quotes parts with '%' in them.
219  StringType GetCommandLineStringInternal(bool quote_placeholders) const;
220
221  // Internal version of GetArgumentsString. If |quote_placeholders| is true,
222  // also quotes parts with '%' in them.
223  StringType GetArgumentsStringInternal(bool quote_placeholders) const;
224
225  // Reconstruct |switches_by_stringpiece| to be a mirror of |switches|.
226  // |switches_by_stringpiece| only contains pointers to objects owned by
227  // |switches|.
228  void ResetStringPieces();
229
230  // The singleton CommandLine representing the current process's command line.
231  static CommandLine* current_process_commandline_;
232
233  // The argv array: { program, [(--|-|/)switch[=value]]*, [--], [argument]* }
234  StringVector argv_;
235
236  // Parsed-out switch keys and values.
237  SwitchMap switches_;
238
239  // A mirror of |switches_| with only references to the actual strings.
240  // The StringPiece internally holds a pointer to a key in |switches_| while
241  // the mapped_type points to a value in |switches_|.
242  // Used for allocation-free lookups.
243  StringPieceSwitchMap switches_by_stringpiece_;
244
245  // The index after the program and switches, any arguments start here.
246  size_t begin_args_;
247};
248
249}  // namespace base
250
251#endif  // BASE_COMMAND_LINE_H_
252