CommandLine refactoring and cleanup.

base/command_line.h

Index: base/command_line.h
diff --git a/base/command_line.h b/base/command_line.h
index b8bbba92e224ee8934f3df6d030b54980207596a..34cd9cb6f9fe607f0ba8a6cd0b1d5fc57626054a 100644
--- a/base/command_line.h
+++ b/base/command_line.h
@@ -3,15 +3,13 @@
 // found in the LICENSE file.
 
 // This class works with command lines: building and parsing.
-// Switches can optionally have a value attached using an equals sign,
-// as in "-switch=value".  Arguments that aren't prefixed with a
-// switch prefix are saved as extra arguments.  An argument of "--"
-// will terminate switch parsing, causing everything after to be
-// considered as extra arguments.
+// Switches can optionally have a value attached using an equals sign, as in
+// "-switch=value". Arguments that aren't prefixed with a switch prefix are
+// saved as extra arguments. An argument of "--" will terminate switch parsing,
+// causing everything after to be considered as extra arguments.
 
-// There is a singleton read-only CommandLine that represents the command
-// line that the current process was started with.  It must be initialized
-// in main() (or whatever the platform's equivalent function is).
+// There is a singleton read-only CommandLine that represents the command line
+// that the current process was started with. It must be initialized in main().
 
 #ifndef BASE_COMMAND_LINE_H_
 #define BASE_COMMAND_LINE_H_
@@ -24,123 +22,104 @@
 #include "base/basictypes.h"
 #include "build/build_config.h"
 
+using std::string;

[evanm, 2011/02/24 01:01:05]

This is against Chrome style.  Typing out std:: everywhere drove me crazy my
first year and eventually I got used to it.

[msw, 2011/05/10 23:18:43]

Done.

+
 class FilePath;
 class InProcessBrowserTest;
 
 class CommandLine {
  public:
+  // The native command line string type.
 #if defined(OS_WIN)
-  // The type of native command line arguments.
-  typedef std::wstring StringType;
+   typedef std::wstring StringType;

[evanm, 2011/02/24 01:01:05]

probably didn't mean to add that whitespace

[msw, 2011/05/10 23:18:43]

Done.

 #elif defined(OS_POSIX)
-  // The type of native command line arguments.
-  typedef std::string StringType;
+  typedef string StringType;
 #endif
+  typedef StringType::value_type CharType;
 
-  // The type of map for parsed-out switch key and values.
-  typedef std::map<std::string, StringType> SwitchMap;
+  typedef std::vector<StringType> StringVector;
+  // The type of map for parsed-out switch keys and values.
+  typedef std::map<string, StringType> SwitchMap;
 
-  // A constructor for CommandLines that are used only to carry switches and
-  // arguments.
+  // Enum & constructor for CommandLines that only carry switches and arguments.
   enum NoProgram { NO_PROGRAM };
   explicit CommandLine(NoProgram no_program);
 
-  // Construct a new, empty command line.
-  // |program| is the name of the program to run (aka argv[0]).
+  // Construct a new command line with |program| as argv[0].
   explicit CommandLine(const FilePath& program);
+  explicit CommandLine(int argc, const CharType* const* argv);
+  explicit CommandLine(const StringVector& argv);
 
-#if defined(OS_POSIX)
-  CommandLine(int argc, const char* const* argv);
-  explicit CommandLine(const std::vector<std::string>& argv);
-#endif
-
-  ~CommandLine();
-
-#if defined(OS_WIN)
-  // Initialize by parsing the given command-line string.
-  // The program name is assumed to be the first item in the string.
-  void ParseFromString(const std::wstring& command_line);
-  static CommandLine FromString(const std::wstring& command_line);
-#elif defined(OS_POSIX)
-  // Initialize from an argv vector.
-  void InitFromArgv(int argc, const char* const* argv);
-  void InitFromArgv(const std::vector<std::string>& argv);
-#endif
-
-  // Initialize the current process CommandLine singleton.  On Windows,
-  // ignores its arguments (we instead parse GetCommandLineW()
-  // directly) because we don't trust the CRT's parsing of the command
-  // line, but it still must be called to set up the command line.
+  // Initialize the current process CommandLine singleton. On Windows, ignores
+  // its arguments (we instead parse GetCommandLineW() directly) because we
+  // don't trust the CRT's parsing of the command-line, but it still must be
+  // called to set up the command line.
   static void Init(int argc, const char* const* argv);
 
   // Destroys the current process CommandLine singleton. This is necessary if
-  // you want to reset the base library to its initial state (for example in an
+  // you want to reset the base library to its initial state (for example, in an
   // outer library that needs to be able to terminate, and be re-initialized).
-  // If Init is called only once, e.g. in main(), calling Reset() is not
-  // necessary.
+  // If Init is called only once, as in main(), Reset() is not necessary.
   static void Reset();
 
   // Get the singleton CommandLine representing the current process's
-  // command line.  Note: returned value is mutable, but not thread safe;
+  // command line. Note: returned value is mutable, but not thread safe;
   // only mutate if you know what you're doing!
   static CommandLine* ForCurrentProcess();
 
+#if defined(OS_WIN)
+  static CommandLine FromString(const StringType& command_line);
+#endif
+
+  // Initialize from an argv vector.
+  void InitFromArgv(int argc, const CharType* const* argv);
+  void InitFromArgv(const StringVector argv);
+
   // Returns true if this command line contains the given switch.
-  // (Switch names are case-insensitive.)
-  bool HasSwitch(const std::string& switch_string) const;
+  // (Switch names are case-insensitive).
+  bool HasSwitch(const string& switch_string) const;
 
-  // Returns the value associated with the given switch.  If the
-  // switch has no value or isn't present, this method returns
-  // the empty string.
-  std::string GetSwitchValueASCII(const std::string& switch_string) const;
-  FilePath GetSwitchValuePath(const std::string& switch_string) const;
-  StringType GetSwitchValueNative(const std::string& switch_string) const;
+  // Returns the value associated with the given switch. If the switch has no
+  // value or isn't present, this method returns the empty string.
+  string GetSwitchValueASCII(const string& switch_string) const;
+  FilePath GetSwitchValuePath(const string& switch_string) const;
+  StringType GetSwitchValueNative(const string& switch_string) const;
 
   // Get the number of switches in this process.
-  size_t GetSwitchCount() const { return switches_.size(); }
+  size_t GetSwitchCount() const;
 
-  // Get a copy of all switches, along with their values
-  const SwitchMap& GetSwitches() const {
-    return switches_;
-  }
+  // Get a copy of all switches, along with their values.
+  const SwitchMap& GetSwitches() const { return switches_; }
 
   // Get the remaining arguments to the command.
-  const std::vector<StringType>& args() const { return args_; }
+  StringVector args() const;

[evanm, 2011/02/24 01:01:05]

I guess if it's not a simple getter it ought to be renamed. (GetArgs or
whatever.)

[msw, 2011/05/10 23:18:43]

Added TODO (to keep this change smaller).

 
-#if defined(OS_WIN)
-  // Returns the original command line string.
-  const std::wstring& command_line_string() const {
-    return command_line_string_;
-  }
-#elif defined(OS_POSIX)
   // Returns the original command line string as a vector of strings.
-  const std::vector<std::string>& argv() const {
-    return argv_;
-  }
-  // Try to match the same result as command_line_string() would get you
-  // on windows.
-  std::string command_line_string() const;
-#endif
+  const StringVector& argv() const { return argv_; }
+
+  // Constructs and returns the represented command line string.
+  StringType command_line_string() const;
 
   // Returns the program part of the command line string (the first item).
   FilePath GetProgram() const;
 
+  // Sets the program part of the command line string (the first item).
+  void SetProgram(const CommandLine::StringType& program);
+
   // Append a switch to the command line.
-  void AppendSwitch(const std::string& switch_string);
+  void AppendSwitch(const string& switch_string);
 
   // Append a switch and value to the command line.
-  void AppendSwitchPath(const std::string& switch_string, const FilePath& path);
-  void AppendSwitchNative(const std::string& switch_string,
-                          const StringType& value);
-  void AppendSwitchASCII(const std::string& switch_string,
-                         const std::string& value);
-
-  // Append an argument to the command line.
-  // Note on quoting: the argument will be quoted properly such that it is
-  // interpreted as one argument to the target command.
-  // AppendArg is primarily for ASCII; non-ASCII input will be
-  // interpreted as UTF-8.
-  void AppendArg(const std::string& value);
+  void AppendSwitchPath(const string& switch_string, const FilePath& path);
+  void AppendSwitchNative(const string& switch_string, const StringType& value);
+  void AppendSwitchASCII(const string& switch_string, const string& value);
+
+  void AppendSwitches(const CommandLine& other);
+
+  // Append an argument to the command line. Note that the argument is quoted
+  // properly such that it is interpreted as one argument to the target command.
+  // AppendArg is primarily for ASCII; non-ASCII input is interpreted as UTF-8.
+  void AppendArg(const string& value);
   void AppendArgPath(const FilePath& value);
   void AppendArgNative(const StringType& value);
 
@@ -149,57 +128,41 @@ class CommandLine {
   void AppendArguments(const CommandLine& other,
                        bool include_program);
 
-  // Insert a command before the current command.  Common for debuggers,
+  // Insert a command before the current command. Common for debuggers,
   // like "valgrind" or "gdb --args".
   void PrependWrapper(const StringType& wrapper);
 
   // Copy a set of switches (and their values, if any) from another command
-  // line.  Commonly used when launching a subprocess.
+  // line. Commonly used when launching a subprocess.
   void CopySwitchesFrom(const CommandLine& source, const char* const switches[],
                         size_t count);
 
+#if defined(OS_WIN)
+  // Initialize by parsing the given command-line string.
+  void ParseFromString(const StringType& command_line);
+#endif
+
  private:
   friend class InProcessBrowserTest;

[Paweł Hajdan Jr., 2011/02/25 18:01:53]

Bonus points for getting rid of that friend declaration.

[msw, 2011/05/10 23:18:43]

Done in r76339.

 
-  CommandLine();
-
-  // Used by InProcessBrowserTest.
-  static CommandLine* ForCurrentProcessMutable();
-
-  // Returns true and fills in |switch_string| and |switch_value|
-  // if |parameter_string| represents a switch.
-  static bool IsSwitch(const StringType& parameter_string,
-                       std::string* switch_string,
-                       StringType* switch_value);
+  // Disallow default constructor; a program name must be explicitly specified.
+  CommandLine() { divider_ = 0; }

[evanm, 2011/02/24 01:01:05]

Why provide an impl if it's not to be run?

[msw, 2011/05/10 23:18:43]

Done, but it'd be cleaner to just replace the NO_PROGRAM ctor  with the default.
What do you think?

+  // Allow the copy constructor. A common pattern is to copy of the current
+  // process's command line and then add some flags to it. For example:
+  //   CommandLine cl(*CommandLine::ForCurrentProcess());
+  //   cl.AppendSwitch(...);
 
-  // The singleton CommandLine instance representing the current process's
-  // command line.
+  // The singleton CommandLine representing the current process's command-line.
   static CommandLine* current_process_commandline_;
 
-  // We store a platform-native version of the command line, used when building
-  // up a new command line to be executed.  This ifdef delimits that code.
+  // The argv array; program name is in argv_[0], then switches, then arguments.
+  StringVector argv_;
 
-#if defined(OS_WIN)
-  // The quoted, space-separated command-line string.
-  std::wstring command_line_string_;
-  // The name of the program.
-  std::wstring program_;
-#elif defined(OS_POSIX)
-  // The argv array, with the program name in argv_[0].
-  std::vector<std::string> argv_;
-#endif
+  // An index dividing switches from arguments in |argv_|.

[evanm, 2011/02/24 01:01:05]

Might be clearer if you say what it is (the position of the first argument? the
position of the last switch?) in addition to what it does.

[msw, 2011/05/10 23:18:43]

Done.

+  size_t divider_;
 
-  // Parsed-out values.
+  // Parsed-out switch keys and values.
   SwitchMap switches_;
-
-  // Non-switch command-line arguments.
-  std::vector<StringType> args_;
-
-  // We allow copy constructors, because a common pattern is to grab a
-  // copy of the current process's command line and then add some
-  // flags to it.  E.g.:
-  //   CommandLine cl(*CommandLine::ForCurrentProcess());
-  //   cl.AppendSwitch(...);
 };
 
 #endif  // BASE_COMMAND_LINE_H_