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third_party/cld/base/commandlineflags.h

Index: third_party/cld/base/commandlineflags.h
===================================================================
--- third_party/cld/base/commandlineflags.h	(revision 0)
+++ third_party/cld/base/commandlineflags.h	(revision 0)
@@ -0,0 +1,443 @@
+// Copyright (c) 2006-2009 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 is the file that should be included by any file which declares
+// or defines a command line flag or wants to parse command line flags
+// or print a program usage message (which will include information about
+// flags).  Executive summary, in the form of an example foo.cc file:
+//
+//    #include "foo.h"         // foo.h has a line "DECLARE_int32(start);"
+//
+//    DEFINE_int32(end, 1000, "The last record to read");
+//    DECLARE_bool(verbose);   // some other file has a DEFINE_bool(verbose, ...)
+//
+//    void MyFunc() {
+//      if (FLAGS_verbose) printf("Records %d-%d\n", FLAGS_start, FLAGS_end);
+//    }
+//
+//    Then, at the command-line:
+//       ./foo --noverbose --start=5 --end=100
+
+#ifndef BASE_COMMANDLINEFLAGS_H_
+#define BASE_COMMANDLINEFLAGS_H_
+
+#include <assert.h>
+#include <string>
+#include <vector>
+#include "base/basictypes.h"
+#include "base/port.h"
+#include "third_party/cld/base/stl_decl.h"
+#include "third_party/cld/base/global_strip_options.h"
+
+// --------------------------------------------------------------------
+// To actually define a flag in a file, use DEFINE_bool,
+// DEFINE_string, etc. at the bottom of this file.  You may also find
+// it useful to register a validator with the flag.  This ensures that
+// when the flag is parsed from the commandline, or is later set via
+// SetCommandLineOption, we call the validation function.
+//
+// The validation function should return true if the flag value is valid, and
+// false otherwise. If the function returns false for the new setting of the
+// flag, the flag will retain its current value. If it returns false for the
+// default value, InitGoogle will die.
+//
+// This function is safe to call at global construct time (as in the
+// example below).
+//
+// Example use:
+//    static bool ValidatePort(const char* flagname, int32 value) {
+//       if (value > 0 && value < 32768)   // value is ok
+//         return true;
+//       printf("Invalid value for --%s: %d\n", flagname, (int)value);
+//       return false;
+//    }
+//    DEFINE_int32(port, 0, "What port to listen on");
+//    static bool dummy = RegisterFlagValidator(&FLAGS_port, &ValidatePort);
+
+// Returns true if successfully registered, false if not (because the
+// first argument doesn't point to a command-line flag, or because a
+// validator is already registered for this flag).
+bool RegisterFlagValidator(const bool* flag,
+                           bool (*validate_fn)(const char*, bool));
+bool RegisterFlagValidator(const int32* flag,
+                           bool (*validate_fn)(const char*, int32));
+bool RegisterFlagValidator(const int64* flag,
+                           bool (*validate_fn)(const char*, int64));
+bool RegisterFlagValidator(const uint64* flag,
+                           bool (*validate_fn)(const char*, uint64));
+bool RegisterFlagValidator(const double* flag,
+                           bool (*validate_fn)(const char*, double));
+bool RegisterFlagValidator(const string* flag,
+                           bool (*validate_fn)(const char*, const string&));
+
+
+// --------------------------------------------------------------------
+// These methods are the best way to get access to info about the
+// list of commandline flags.  Note that these routines are pretty slow.
+//   GetAllFlags: mostly-complete info about the list, sorted by file.
+//   ShowUsageWithFlags: pretty-prints the list to stdout (what --help does)
+//   ShowUsageWithFlagsRestrict: limit to filenames with restrict as a substr
+//
+// In addition to accessing flags, you can also access argv[0] (the program
+// name) and argv (the entire commandline), which we sock away a copy of.
+// These variables are static, so you should only set them once.
+
+struct CommandLineFlagInfo {
+  string name;            // the name of the flag
+  string type;            // the type of the flag: int32, etc
+  string description;     // the "help text" associated with the flag
+  string current_value;   // the current value, as a string
+  string default_value;   // the default value, as a string
+  string filename;        // 'cleaned' version of filename holding the flag
+  bool is_default;        // true if the flag has default value
+  bool has_validator_fn;  // true if RegisterFlagValidator called on this flag
+};
+
+extern void GetAllFlags(vector<CommandLineFlagInfo>* OUTPUT);
+// These two are actually defined in commandlineflags_reporting.cc.
+extern void ShowUsageWithFlags(const char *argv0);  // what --help does
+extern void ShowUsageWithFlagsRestrict(const char *argv0, const char *restrict);
+
+// Create a descriptive string for a flag.
+// Goes to some trouble to make pretty line breaks.
+extern string DescribeOneFlag(const CommandLineFlagInfo& flag);
+
+// Thread-hostile; meant to be called before any threads are spawned.
+extern void SetArgv(int argc, const char** argv);
+// The following functions are thread-safe as long as SetArgv() is
+// only called before any threads start.
+extern const vector<string>& GetArgvs();    // all of argv = vector of strings
+extern const char* GetArgv();               // all of argv as a string
+extern const char* GetArgv0();              // only argv0
+extern uint32 GetArgvSum();                 // simple checksum of argv
+extern const char* ProgramInvocationName(); // argv0, or "UNKNOWN" if not set
+extern const char* ProgramInvocationShortName();   // basename(argv0)
+// ProgramUsage() is thread-safe as long as SetUsageMessage() is only
+// called before any threads start.
+extern const char* ProgramUsage();          // string set by SetUsageMessage()
+
+
+// --------------------------------------------------------------------
+// Normally you access commandline flags by just saying "if (FLAGS_foo)"
+// or whatever, and set them by calling "FLAGS_foo = bar" (or, more
+// commonly, via the DEFINE_foo macro).  But if you need a bit more
+// control, we have programmatic ways to get/set the flags as well.
+// These programmatic ways to access flags are thread-safe, but direct
+// access is only thread-compatible.
+
+// Return true iff the flagname was found.
+// OUTPUT is set to the flag's value, or unchanged if we return false.
+extern bool GetCommandLineOption(const char* name, string* OUTPUT);
+
+// Return true iff the flagname was found. OUTPUT is set to the flag's
+// CommandLineFlagInfo or unchanged if we return false.
+extern bool GetCommandLineFlagInfo(const char* name,
+                                   CommandLineFlagInfo* OUTPUT);
+
+// Return the CommandLineFlagInfo of the flagname.  exit() if name not found.
+// Example usage, to check if a flag's value is currently the default value:
+//   if (GetCommandLineFlagInfoOrDie("foo").is_default) ...
+extern CommandLineFlagInfo GetCommandLineFlagInfoOrDie(const char* name);
+
+enum FlagSettingMode {
+  // update the flag's value (can call this multiple times).
+  SET_FLAGS_VALUE,
+  // update the flag's value, but *only if* it has not yet been updated
+  // with SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef".
+  SET_FLAG_IF_DEFAULT,
+  // set the flag's default value to this.  If the flag has not yet updated
+  // yet (via SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef")
+  // change the flag's current value to the new default value as well.
+  SET_FLAGS_DEFAULT
+};
+
+// Set a particular flag ("command line option").  Returns a string
+// describing the new value that the option has been set to.  The
+// return value API is not well-specified, so basically just depend on
+// it to be empty if the setting failed for some reason -- the name is
+// not a valid flag name, or the value is not a valid value -- and
+// non-empty else.
+
+// SetCommandLineOption uses set_mode == SET_FLAGS_VALUE (the common case)
+extern string SetCommandLineOption(const char* name, const char* value);
+extern string SetCommandLineOptionWithMode(const char* name, const char* value,
+                                           FlagSettingMode set_mode);
+
+
+// --------------------------------------------------------------------
+// Saves the states (value, default value, whether the user has set
+// the flag, registered validators, etc) of all flags, and restores
+// them when the FlagSaver is destroyed.  This is very useful in
+// tests, say, when you want to let your tests change the flags, but
+// make sure that they get reverted to the original states when your
+// test is complete.
+//
+// Example usage:
+//   void TestFoo() {
+//     FlagSaver s1;
+//     FLAG_foo = false;
+//     FLAG_bar = "some value";
+//
+//     // test happens here.  You can return at any time
+//     // without worrying about restoring the FLAG values.
+//   }
+//
+// Note: This class is marked with ATTRIBUTE_UNUSED because all the
+// work is done in the constructor and destructor, so in the standard
+// usage example above, the compiler would complain that it's an
+// unused variable.
+//
+// This class is thread-safe.
+/*
+class FlagSaver {
+ public:
+  FlagSaver();
+  ~FlagSaver();
+
+ private:
+  class FlagSaverImpl* impl_;   // we use pimpl here to keep API steady
+
+  FlagSaver(const FlagSaver&);  // no copying!
+  void operator=(const FlagSaver&);
+}
+#ifndef SWIG   // swig seems to have trouble with this for some reason
+ATTRIBUTE_UNUSED
+#endif
+;
+*/
+// --------------------------------------------------------------------
+// Some deprecated or hopefully-soon-to-be-deprecated functions.
+
+// This is often used for logging.  TODO(csilvers): figure out a better way
+extern string CommandlineFlagsIntoString();
+// Usually where this is used, a FlagSaver should be used instead.
+extern bool ReadFlagsFromString(const string& flagfilecontents,
+                                const char* prog_name,
+                                bool errors_are_fatal); // uses SET_FLAGS_VALUE
+
+// These let you manually implement --flagfile functionality.
+// DEPRECATED.
+extern bool AppendFlagsIntoFile(const string& filename, const char* prog_name);
+extern bool SaveCommandFlags();  // actually defined in google.cc !
+extern bool ReadFromFlagsFile(const string& filename, const char* prog_name,
+                              bool errors_are_fatal);   // uses SET_FLAGS_VALUE
+
+
+// --------------------------------------------------------------------
+// Useful routines for initializing flags from the environment.
+// In each case, if 'varname' does not exist in the environment
+// return defval.  If 'varname' does exist but is not valid
+// (e.g., not a number for an int32 flag), abort with an error.
+// Otherwise, return the value.  NOTE: for booleans, for true use
+// 't' or 'T' or 'true' or '1', for false 'f' or 'F' or 'false' or '0'.
+
+extern bool BoolFromEnv(const char *varname, bool defval);
+extern int32 Int32FromEnv(const char *varname, int32 defval);
+extern int64 Int64FromEnv(const char *varname, int64 defval);
+extern uint64 Uint64FromEnv(const char *varname, uint64 defval);
+extern double DoubleFromEnv(const char *varname, double defval);
+extern const char *StringFromEnv(const char *varname, const char *defval);
+
+
+// --------------------------------------------------------------------
+// The next two functions parse commandlineflags from main():
+
+// Set the "usage" message for this program.  For example:
+//   string usage("This program does nothing.  Sample usage:\n");
+//   usage += argv[0] + " <uselessarg1> <uselessarg2>";
+//   SetUsageMessage(usage);
+// Do not include commandline flags in the usage: we do that for you!
+// Thread-hostile; meant to be called before any threads are spawned.
+extern void SetUsageMessage(const string& usage);
+
+// Looks for flags in argv and parses them.  Rearranges argv to put
+// flags first, or removes them entirely if remove_flags is true.
+// If a flag is defined more than once in the command line or flag
+// file, the last definition is used.
+// See top-of-file for more details on this function.
+#ifndef SWIG   // In swig, use ParseCommandLineFlagsScript() instead.
+extern uint32 ParseCommandLineFlags(int *argc, char*** argv,
+                                    bool remove_flags);
+#endif
+
+
+// Calls to ParseCommandLineNonHelpFlags and then to
+// HandleCommandLineHelpFlags can be used instead of a call to
+// ParseCommandLineFlags during initialization, in order to allow for
+// changing default values for some FLAGS (via
+// e.g. SetCommandLineOptionWithMode calls) between the time of
+// command line parsing and the time of dumping help information for
+// the flags as a result of command line parsing.
+// If a flag is defined more than once in the command line or flag
+// file, the last definition is used.
+extern uint32 ParseCommandLineNonHelpFlags(int *argc, char*** argv,
+                                           bool remove_flags);
+// This is actually defined in commandlineflags_reporting.cc.
+// This function is misnamed (it also handles --version, etc.), but
+// it's too late to change that now. :-(
+extern void HandleCommandLineHelpFlags();   // in commandlineflags_reporting.cc
+
+// Allow command line reparsing.  Disables the error normally
+// generated when an unknown flag is found, since it may be found in a
+// later parse.  Thread-hostile; meant to be called before any threads
+// are spawned.
+extern void AllowCommandLineReparsing();
+
+// Reparse the flags that have not yet been recognized.
+// Only flags registered since the last parse will be recognized.
+// Any flag value must be provided as part of the argument using "=",
+// not as a separate command line argument that follows the flag argument.
+// Intended for handling flags from dynamically loaded libraries,
+// since their flags are not registered until they are loaded.
+extern uint32 ReparseCommandLineNonHelpFlags();
+
+
+// --------------------------------------------------------------------
+// Now come the command line flag declaration/definition macros that
+// will actually be used.  They're kind of hairy.  A major reason
+// for this is initialization: we want people to be able to access
+// variables in global constructors and have that not crash, even if
+// their global constructor runs before the global constructor here.
+// (Obviously, we can't guarantee the flags will have the correct
+// default value in that case, but at least accessing them is safe.)
+// The only way to do that is have flags point to a static buffer.
+// So we make one, using a union to ensure proper alignment, and
+// then use placement-new to actually set up the flag with the
+// correct default value.  In the same vein, we have to worry about
+// flag access in global destructors, so FlagRegisterer has to be
+// careful never to destroy the flag-values it constructs.
+//
+// Note that when we define a flag variable FLAGS_<name>, we also
+// preemptively define a junk variable, FLAGS_no<name>.  This is to
+// cause a link-time error if someone tries to define 2 flags with
+// names like "logging" and "nologging".  We do this because a bool
+// flag FLAG can be set from the command line to true with a "-FLAG"
+// argument, and to false with a "-noFLAG" argument, and so this can
+// potentially avert confusion.
+//
+// We also put flags into their own namespace.  It is purposefully
+// named in an opaque way that people should have trouble typing
+// directly.  The idea is that DEFINE puts the flag in the weird
+// namespace, and DECLARE imports the flag from there into the current
+// namespace.  The net result is to force people to use DECLARE to get
+// access to a flag, rather than saying "extern bool FLAGS_whatever;"
+// or some such instead.  We want this so we can put extra
+// functionality (like sanity-checking) in DECLARE if we want, and
+// make sure it is picked up everywhere.
+//
+// We also put the type of the variable in the namespace, so that
+// people can't DECLARE_int32 something that they DEFINE_bool'd
+// elsewhere.
+
+class FlagRegisterer {
+ public:
+  FlagRegisterer(const char* name, const char* type,
+                 const char* help, const char* filename,
+                 void* current_storage, void* defvalue_storage);
+};
+
+#ifndef SWIG  // In swig, ignore the main flag declarations
+
+// If STRIP_FLAG_HELP is defined and is non-zero, we remove the help
+// message from the binary file. This is useful for security reasons
+// when shipping a binary outside of Google (if the user cannot see
+// the usage message by executing the program, they shouldn't be able
+// to see it by running "strings binary_file").
+
+extern const char kStrippedFlagHelp[];
+
+#if STRIP_FLAG_HELP > 0
+// Need this construct to avoid the 'defined but not used' warning.
+#define MAYBE_STRIPPED_HELP(txt) (false ? (txt) : kStrippedFlagHelp)
+#else
+#define MAYBE_STRIPPED_HELP(txt) txt
+#endif
+
+// Each command-line flag has two variables associated with it: one
+// with the current value, and one with the default value.  However,
+// we have a third variable, which is where value is assigned; it's a
+// constant.  This guarantees that FLAG_##value is initialized at
+// static initialization time (e.g. before program-start) rather than
+// than global construction time (which is after program-start but
+// before main), at least when 'value' is a compile-time constant.  We
+// use a small trick for the "default value" variable, and call it
+// FLAGS_no<name>.  This serves the second purpose of assuring a
+// compile error if someone tries to define a flag named no<name>
+// which is illegal (--foo and --nofoo both affect the "foo" flag).
+#define DEFINE_VARIABLE(type, shorttype, name, value, help) \
+  namespace fL##shorttype {                                     \
+    static const type FLAGS_nono##name = value;                 \
+    type FLAGS_##name = FLAGS_nono##name;                       \
+    type FLAGS_no##name = FLAGS_nono##name;                     \
+    static FlagRegisterer o_##name(                             \
+      #name, #type, MAYBE_STRIPPED_HELP(help), __FILE__,        \
+      &FLAGS_##name, &FLAGS_no##name);                          \
+  }                                                             \
+  using fL##shorttype::FLAGS_##name
+
+#define DECLARE_VARIABLE(type, shorttype, name) \
+  namespace fL##shorttype {                     \
+    extern type FLAGS_##name;                   \
+  }                                             \
+  using fL##shorttype::FLAGS_##name
+
+// For boolean flags, we want to do the extra check that the passed-in
+// value is actually a bool, and not a string or something that can be
+// coerced to a bool.  These declarations (no definition needed!) will
+// help us do that, and never evaluate from, which is important.
+// We'll use 'sizeof(IsBool(val))' to distinguish.
+namespace fLB {
+template<typename From> double IsBoolFlag(const From& from);
+bool IsBoolFlag(bool from);
+}
+extern bool FlagsTypeWarn(const char *name);
+
+#define DECLARE_bool(name)          DECLARE_VARIABLE(bool,B, name)
+// We have extra code here to make sure 'val' is actually a boolean.
+#define DEFINE_bool(name,val,txt)   namespace fLB { \
+                                      const bool FLAGS_nonono##name = \
+                                        (sizeof(::fLB::IsBoolFlag(val)) \
+                                        == sizeof(double)) \
+                                        ? FlagsTypeWarn(#name) : true; \
+                                    } \
+                                    DEFINE_VARIABLE(bool,B, name, val, txt)
+#define DECLARE_int32(name)         DECLARE_VARIABLE(int32,I, name)
+#define DEFINE_int32(name,val,txt)  DEFINE_VARIABLE(int32,I, name, val, txt)
+
+#define DECLARE_int64(name)         DECLARE_VARIABLE(int64,I64, name)
+#define DEFINE_int64(name,val,txt)  DEFINE_VARIABLE(int64,I64, name, val, txt)
+
+#define DECLARE_uint64(name)        DECLARE_VARIABLE(uint64,U64, name)
+#define DEFINE_uint64(name,val,txt) DEFINE_VARIABLE(uint64,U64, name, val, txt)
+
+#define DECLARE_double(name)        DECLARE_VARIABLE(double,D, name)
+#define DEFINE_double(name,val,txt) DEFINE_VARIABLE(double,D, name, val, txt)
+
+// Strings are trickier, because they're not a POD, so we can't
+// construct them at static-initialization time (instead they get
+// constructed at global-constructor time, which is much later).  To
+// try to avoid crashes in that case, we use a char buffer to store
+// the string, which we can static-initialize, and then placement-new
+// into it later.  It's not perfect, but the best we can do.
+#define DECLARE_string(name)  namespace fLS { extern string& FLAGS_##name; } \
+                              using fLS::FLAGS_##name
+
+// We need to define a var named FLAGS_no##name so people don't define
+// --string and --nostring.  And we need a temporary place to put val
+// so we don't have to evaluate it twice.  Two great needs that go
+// great together!
+#define DEFINE_string(name, val, txt)                                     \
+  namespace fLS {                                                         \
+    static union { void* align; char s[sizeof(string)]; } s_##name[2];    \
+    const string* const FLAGS_no##name = new (s_##name[0].s) string(val); \
+    static FlagRegisterer o_##name(                                       \
+      #name, "string", MAYBE_STRIPPED_HELP(txt), __FILE__,                \
+      s_##name[0].s, new (s_##name[1].s) string(*FLAGS_no##name));        \
+    string& FLAGS_##name = *(reinterpret_cast<string*>(s_##name[0].s));   \
+  }                                                                       \
+  using fLS::FLAGS_##name
+
+#endif  // SWIG
+
+#endif  // BASE_COMMANDLINEFLAGS_H_
Property changes on: third_party\cld\base\commandlineflags.h
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Added: svn:eol-style
   + LF