WIP - command line experiment

base/command_line.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This class works with command lines: building and parsing.
 // Arguments with prefixes ('--', '-', and on Windows, '/') are switches.
 // Switches will precede all other arguments without switch prefixes.
 // Switches can optionally have values, delimited by '=', e.g., "-switch=value".
 // An argument of "--" will terminate switch parsing during initialization,
 // interpreting subsequent tokens as non-switch arguments, regardless of prefix.
 
 // 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_
 
 #include <stddef.h>
+#include <stdint.h>
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/base_export.h"
 #include "build/build_config.h"
 
 namespace base {
 class FilePath;
 }
 
 class BASE_EXPORT CommandLine {
  public:
 #if defined(OS_WIN)
   // The native command line string type.
   typedef std::wstring StringType;
 #elif defined(OS_POSIX)
   typedef std::string StringType;
 #endif
 
   typedef StringType::value_type CharType;
   typedef std::vector<StringType> StringVector;
   typedef std::map<std::string, StringType> SwitchMap;
 
+  struct ExplicitStdString {
+    ExplicitStdString(const std::string& str) : s(str) {}
+    const std::string& s;
+  };
+
   // A constructor for CommandLines that only carry switches and arguments.
   enum NoProgram { NO_PROGRAM };
   explicit CommandLine(NoProgram no_program);
 
   // Construct a new command line with |program| as argv[0].
   explicit CommandLine(const base::FilePath& program);
 
   // Construct a new command line from an argument list.
   CommandLine(int argc, const CharType* const* argv);
   explicit CommandLine(const StringVector& argv);
@@ skipping 42 matching lines @@
 
   // Returns the original command line string as a vector of strings.
   const StringVector& argv() const { return argv_; }
 
   // Get and Set the program part of the command line string (the first item).
   base::FilePath GetProgram() const;
   void SetProgram(const base::FilePath& program);
 
   // Returns true if this command line contains the given switch.
   // (Switch names are case-insensitive).
-  bool HasSwitch(const std::string& switch_string) const;
+  bool HasStringSwitch(const std::string& switch_string) const;
+  bool HasSwitch(const ExplicitStdString& switch_string) const {
+    return HasStringSwitch(switch_string.s);
+  }
+  bool HasSwitch(const char* switch_string, size_t string_length) const;
+
+  template <size_t N>
+  bool HasSwitch(const char (&constant_switch_string)[N]) const {
+    // Note that N includes a null terminator, so this will generate a compile
+    // error if called with an empty string constant.
+    if (N <= 65 &&
+        (switch_lengths_mask_ & (static_cast<uint64_t>(1) << (N - 2))) == 0) {
+      return false;
+    }
+
+    return HasSwitch(constant_switch_string, N - 1);
+  }
 
   // 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;
   base::FilePath GetSwitchValuePath(const std::string& switch_string) const;
   StringType GetSwitchValueNative(const std::string& switch_string) const;
 
   // Get a copy of all switches, along with their values.
   const SwitchMap& GetSwitches() const { return switches_; }
 
@@ skipping 50 matching lines @@
   static CommandLine* current_process_commandline_;
 
   // The argv array: { program, [(--|-|/)switch[=value]]*, [--], [argument]* }
   StringVector argv_;
 
   // Parsed-out switch keys and values.
   SwitchMap switches_;
 
   // The index after the program and switches, any arguments start here.
   size_t begin_args_;
+
+  // A bitset, with a 1 at bit postion |i| indicating that the command line
+  // includes a switch of string length |i| + 1 ascii characters.
+  uint64_t switch_lengths_mask_;
 };
 
 #endif  // BASE_COMMAND_LINE_H_