base/command_line.h

   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 "build/build_config.h"
  25
  26 class FilePath;
  27
  28 class BASE_EXPORT CommandLine {
  29  public:
  30 #if defined(OS_WIN)
  31   // The native command line string type.
  32   typedef std::wstring StringType;
  33 #elif defined(OS_POSIX)
  34   typedef std::string StringType;
  35 #endif
  36
  37   typedef StringType::value_type CharType;
  38   typedef std::vector<StringType> StringVector;
  39   typedef std::map<std::string, StringType> SwitchMap;
  40
  41   // A constructor for CommandLines that only carry switches and arguments.
  42   enum NoProgram { NO_PROGRAM };
  43   explicit CommandLine(NoProgram no_program);
  44
  45   // Construct a new command line with |program| as argv[0].
  46   explicit CommandLine(const FilePath& program);
  47
  48   // Construct a new command line from an argument list.
  49   CommandLine(int argc, const CharType* const* argv);
  50   explicit CommandLine(const StringVector& argv);
  51
  52   ~CommandLine();
  53
  54   // Initialize the current process CommandLine singleton. On Windows, ignores
  55   // its arguments (we instead parse GetCommandLineW() directly) because we
  56   // don't trust the CRT's parsing of the command line, but it still must be
  57   // called to set up the command line. Returns false if initialization has
  58   // already occurred, and true otherwise. Only the caller receiving a 'true'
  59   // return value should take responsibility for calling Reset.
  60   static bool Init(int argc, const char* const* argv);
  61
  62   // Destroys the current process CommandLine singleton. This is necessary if
  63   // you want to reset the base library to its initial state (for example, in an
  64   // outer library that needs to be able to terminate, and be re-initialized).
  65   // If Init is called only once, as in main(), Reset() is not necessary.
  66   static void Reset();
  67
  68   // Get the singleton CommandLine representing the current process's
  69   // command line. Note: returned value is mutable, but not thread safe;
  70   // only mutate if you know what you're doing!
  71   static CommandLine* ForCurrentProcess();
  72
  73 #if defined(OS_WIN)
  74   static CommandLine FromString(const std::wstring& command_line);
  75 #endif
  76
  77   // Initialize from an argv vector.
  78   void InitFromArgv(int argc, const CharType* const* argv);
  79   void InitFromArgv(const StringVector& argv);
  80
  81   // Constructs and returns the represented command line string.
  82   // CAUTION! This should be avoided on POSIX because quoting behavior is
  83   // unclear.
  84   StringType GetCommandLineString() const;
  85
  86   // Constructs and returns the represented arguments string.
  87   // CAUTION! This should be avoided on POSIX because quoting behavior is
  88   // unclear.
  89   StringType GetArgumentsString() const;
  90
  91   // Returns the original command line string as a vector of strings.
  92   const StringVector& argv() const { return argv_; }
  93
  94   // Get and Set the program part of the command line string (the first item).
  95   FilePath GetProgram() const;
  96   void SetProgram(const FilePath& program);
  97
  98   // Returns true if this command line contains the given switch.
  99   // (Switch names are case-insensitive).
 100   bool HasSwitch(const std::string& switch_string) const;
 101
 102   // Returns the value associated with the given switch. If the switch has no
 103   // value or isn't present, this method returns the empty string.
 104   std::string GetSwitchValueASCII(const std::string& switch_string) const;
 105   FilePath GetSwitchValuePath(const std::string& switch_string) const;
 106   StringType GetSwitchValueNative(const std::string& switch_string) const;
 107
 108   // Get a copy of all switches, along with their values.
 109   const SwitchMap& GetSwitches() const { return switches_; }
 110
 111   // Append a switch [with optional value] to the command line.
 112   // Note: Switches will precede arguments regardless of appending order.
 113   void AppendSwitch(const std::string& switch_string);
 114   void AppendSwitchPath(const std::string& switch_string, const FilePath& path);
 115   void AppendSwitchNative(const std::string& switch_string,
 116                           const StringType& value);
 117   void AppendSwitchASCII(const std::string& switch_string,
 118                          const std::string& value);
 119
 120   // Copy a set of switches (and any values) from another command line.
 121   // Commonly used when launching a subprocess.
 122   void CopySwitchesFrom(const CommandLine& source,
 123                         const char* const switches[],
 124                         size_t count);
 125
 126   // Get the remaining arguments to the command.
 127   StringVector GetArgs() const;
 128
 129   // Append an argument to the command line. Note that the argument is quoted
 130   // properly such that it is interpreted as one argument to the target command.
 131   // AppendArg is primarily for ASCII; non-ASCII input is interpreted as UTF-8.
 132   // Note: Switches will precede arguments regardless of appending order.
 133   void AppendArg(const std::string& value);
 134   void AppendArgPath(const FilePath& value);
 135   void AppendArgNative(const StringType& value);
 136
 137   // Append the switches and arguments from another command line to this one.
 138   // If |include_program| is true, include |other|'s program as well.
 139   void AppendArguments(const CommandLine& other, bool include_program);
 140
 141   // Insert a command before the current command.
 142   // Common for debuggers, like "valgrind" or "gdb --args".
 143   void PrependWrapper(const StringType& wrapper);
 144
 145 #if defined(OS_WIN)
 146   // Initialize by parsing the given command line string.
 147   // The program name is assumed to be the first item in the string.
 148   void ParseFromString(const std::wstring& command_line);
 149 #endif
 150
 151  private:
 152   // Disallow default constructor; a program name must be explicitly specified.
 153   CommandLine();
 154   // Allow the copy constructor. A common pattern is to copy of the current
 155   // process's command line and then add some flags to it. For example:
 156   //   CommandLine cl(*CommandLine::ForCurrentProcess());
 157   //   cl.AppendSwitch(...);
 158
 159   // The singleton CommandLine representing the current process's command line.
 160   static CommandLine* current_process_commandline_;
 161
 162   // The argv array: { program, [(--|-|/)switch[=value]]*, [--], [argument]* }
 163   StringVector argv_;
 164
 165   // Parsed-out switch keys and values.
 166   SwitchMap switches_;
 167
 168   // The index after the program and switches, any arguments start here.
 169   size_t begin_args_;
 170 };
 171
 172 #endif  // BASE_COMMAND_LINE_H_