1 // Copyright (c) 1999, Google Inc.
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5 // modification, are permitted provided that the following conditions are
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31 // Revamped and reorganized by Craig Silverstein
33 // This file contains the implementation of all our command line flags
34 // stuff. Here's how everything fits together
36 // * FlagRegistry owns CommandLineFlags owns FlagValue.
37 // * FlagSaver holds a FlagRegistry (saves it at construct time,
38 // restores it at destroy time).
39 // * CommandLineFlagParser lives outside that hierarchy, but works on
40 // CommandLineFlags (modifying the FlagValues).
41 // * Free functions like SetCommandLineOption() work via one of the
42 // above (such as CommandLineFlagParser).
46 // -- The main classes that hold flag data:
48 // FlagValue holds the current value of a flag. It's
49 // pseudo-templatized: every operation on a FlagValue is typed. It
50 // also deals with storage-lifetime issues (so flag values don't go
51 // away in a destructor), which is why we need a whole class to hold a
54 // CommandLineFlag is all the information about a single command-line
55 // flag. It has a FlagValue for the flag's current value, but also
56 // the flag's name, type, etc.
58 // FlagRegistry is a collection of CommandLineFlags. There's the
59 // global registry, which is where flags defined via DEFINE_foo()
60 // live. But it's possible to define your own flag, manually, in a
61 // different registry you create. (In practice, multiple registries
62 // are used only by FlagSaver).
64 // A given FlagValue is owned by exactly one CommandLineFlag. A given
65 // CommandLineFlag is owned by exactly one FlagRegistry. FlagRegistry
66 // has a lock; any operation that writes to a FlagValue or
67 // CommandLineFlag owned by that registry must acquire the
68 // FlagRegistry lock before doing so.
70 // --- Some other classes and free functions:
72 // CommandLineFlagInfo is a client-exposed version of CommandLineFlag.
73 // Once it's instantiated, it has no dependencies or relationships
74 // with any other part of this file.
76 // FlagRegisterer is the helper class used by the DEFINE_* macros to
77 // allow work to be done at global initialization time.
79 // CommandLineFlagParser is the class that reads from the commandline
80 // and instantiates flag values based on that. It needs to poke into
81 // the innards of the FlagValue->CommandLineFlag->FlagRegistry class
82 // hierarchy to do that. It's careful to acquire the FlagRegistry
83 // lock before doing any writing or other non-const actions.
85 // GetCommandLineOption is just a hook into registry routines to
86 // retrieve a flag based on its name. SetCommandLineOption, on the
87 // other hand, hooks into CommandLineFlagParser. Other API functions
88 // are, similarly, mostly hooks into the functionality described above.
91 #include "gflags/gflags.h"
96 #if defined(HAVE_FNMATCH_H)
98 #elif defined(HAVE_SHLWAPI_H)
99 # define NO_SHLWAPI_ISOS
100 # include <shlwapi.h>
102 #include <stdarg.h> // For va_list and related operations
109 #include <utility> // for pair<>
115 using namespace MUTEX_NAMESPACE;
118 // Special flags, type 1: the 'recursive' flags. They set another flag's val.
119 DEFINE_string(flagfile, "", "load flags from file");
120 DEFINE_string(fromenv, "", "set flags from the environment"
121 " [use 'export FLAGS_flag1=value']");
122 DEFINE_string(tryfromenv, "", "set flags from the environment if present");
124 // Special flags, type 2: the 'parsing' flags. They modify how we parse.
125 DEFINE_string(undefok, "", "comma-separated list of flag names that it is okay to specify "
126 "on the command line even if the program does not define a flag "
127 "with that name. IMPORTANT: flags in this list that have "
128 "arguments MUST use the flag=value format");
130 namespace GFLAGS_NAMESPACE {
138 // This is used by the unittest to test error-exit code
139 void GFLAGS_DLL_DECL (*gflags_exitfunc)(int) = &exit; // from stdlib.h
142 // The help message indicating that the commandline flag has been
143 // 'stripped'. It will not show up when doing "-help" and its
144 // variants. The flag is stripped if STRIP_FLAG_HELP is set to 1
145 // before including base/gflags.h
147 // This is used by this file, and also in gflags_reporting.cc
148 const char kStrippedFlagHelp[] = "\001\002\003\004 (unknown) \004\003\002\001";
152 // There are also 'reporting' flags, in gflags_reporting.cc.
154 static const char kError[] = "ERROR: ";
156 // Indicates that undefined options are to be ignored.
157 // Enables deferred processing of flags in dynamically loaded libraries.
158 static bool allow_command_line_reparsing = false;
160 static bool logging_is_probably_set_up = false;
162 // This is a 'prototype' validate-function. 'Real' validate
163 // functions, take a flag-value as an argument: ValidateFn(bool) or
164 // ValidateFn(uint64). However, for easier storage, we strip off this
165 // argument and then restore it when actually calling the function on
167 typedef bool (*ValidateFnProto)();
169 // Whether we should die when reporting an error.
170 enum DieWhenReporting { DIE, DO_NOT_DIE };
172 // Report Error and exit if requested.
173 static void ReportError(DieWhenReporting should_die, const char* format, ...) {
175 va_start(ap, format);
176 vfprintf(stderr, format, ap);
178 fflush(stderr); // should be unnecessary, but cygwin's rxvt buffers stderr
179 if (should_die == DIE) gflags_exitfunc(1);
183 // --------------------------------------------------------------------
185 // This represent the value a single flag might have. The major
186 // functionality is to convert from a string to an object of a
187 // given type, and back. Thread-compatible.
188 // --------------------------------------------------------------------
190 class CommandLineFlag;
204 template <typename FlagType>
205 FlagValue(FlagType* valbuf, bool transfer_ownership_of_value);
208 bool ParseFrom(const char* spec);
209 string ToString() const;
211 ValueType Type() const { return static_cast<ValueType>(type_); }
214 friend class CommandLineFlag; // for many things, including Validate()
215 friend class GFLAGS_NAMESPACE::FlagSaverImpl; // calls New()
216 friend class FlagRegistry; // checks value_buffer_ for flags_by_ptr_ map
217 template <typename T> friend T GetFromEnv(const char*, T);
218 friend bool TryParseLocked(const CommandLineFlag*, FlagValue*,
219 const char*, string*); // for New(), CopyFrom()
221 template <typename FlagType>
222 struct FlagValueTraits;
224 const char* TypeName() const;
225 bool Equal(const FlagValue& x) const;
226 FlagValue* New() const; // creates a new one with default value
227 void CopyFrom(const FlagValue& x);
228 int ValueSize() const;
230 // Calls the given validate-fn on value_buffer_, and returns
231 // whatever it returns. But first casts validate_fn_proto to a
232 // function that takes our value as an argument (eg void
233 // (*validate_fn)(bool) for a bool flag).
234 bool Validate(const char* flagname, ValidateFnProto validate_fn_proto) const;
236 void* const value_buffer_; // points to the buffer holding our data
237 const int8 type_; // how to interpret value_
238 const bool owns_value_; // whether to free value on destruct
240 FlagValue(const FlagValue&); // no copying!
241 void operator=(const FlagValue&);
244 // Map the given C++ type to a value of the ValueType enum at compile time.
245 #define DEFINE_FLAG_TRAITS(type, value) \
247 struct FlagValue::FlagValueTraits<type> { \
248 static const ValueType kValueType = value; \
251 // Define full template specializations of the FlagValueTraits template
252 // for all supported flag types.
253 DEFINE_FLAG_TRAITS(bool, FV_BOOL);
254 DEFINE_FLAG_TRAITS(int32, FV_INT32);
255 DEFINE_FLAG_TRAITS(uint32, FV_UINT32);
256 DEFINE_FLAG_TRAITS(int64, FV_INT64);
257 DEFINE_FLAG_TRAITS(uint64, FV_UINT64);
258 DEFINE_FLAG_TRAITS(double, FV_DOUBLE);
259 DEFINE_FLAG_TRAITS(std::string, FV_STRING);
261 #undef DEFINE_FLAG_TRAITS
264 // This could be a templated method of FlagValue, but doing so adds to the
265 // size of the .o. Since there's no type-safety here anyway, macro is ok.
266 #define VALUE_AS(type) *reinterpret_cast<type*>(value_buffer_)
267 #define OTHER_VALUE_AS(fv, type) *reinterpret_cast<type*>(fv.value_buffer_)
268 #define SET_VALUE_AS(type, value) VALUE_AS(type) = (value)
270 template <typename FlagType>
271 FlagValue::FlagValue(FlagType* valbuf,
272 bool transfer_ownership_of_value)
273 : value_buffer_(valbuf),
274 type_(FlagValueTraits<FlagType>::kValueType),
275 owns_value_(transfer_ownership_of_value) {
278 FlagValue::~FlagValue() {
283 case FV_BOOL: delete reinterpret_cast<bool*>(value_buffer_); break;
284 case FV_INT32: delete reinterpret_cast<int32*>(value_buffer_); break;
285 case FV_UINT32: delete reinterpret_cast<uint32*>(value_buffer_); break;
286 case FV_INT64: delete reinterpret_cast<int64*>(value_buffer_); break;
287 case FV_UINT64: delete reinterpret_cast<uint64*>(value_buffer_); break;
288 case FV_DOUBLE: delete reinterpret_cast<double*>(value_buffer_); break;
289 case FV_STRING: delete reinterpret_cast<string*>(value_buffer_); break;
293 bool FlagValue::ParseFrom(const char* value) {
294 if (type_ == FV_BOOL) {
295 const char* kTrue[] = { "1", "t", "true", "y", "yes" };
296 const char* kFalse[] = { "0", "f", "false", "n", "no" };
297 COMPILE_ASSERT(sizeof(kTrue) == sizeof(kFalse), true_false_equal);
298 for (size_t i = 0; i < sizeof(kTrue)/sizeof(*kTrue); ++i) {
299 if (strcasecmp(value, kTrue[i]) == 0) {
300 SET_VALUE_AS(bool, true);
302 } else if (strcasecmp(value, kFalse[i]) == 0) {
303 SET_VALUE_AS(bool, false);
307 return false; // didn't match a legal input
309 } else if (type_ == FV_STRING) {
310 SET_VALUE_AS(string, value);
314 // OK, it's likely to be numeric, and we'll be using a strtoXXX method.
315 if (value[0] == '\0') // empty-string is only allowed for string type.
318 // Leading 0x puts us in base 16. But leading 0 does not put us in base 8!
319 // It caused too many bugs when we had that behavior.
320 int base = 10; // by default
321 if (value[0] == '0' && (value[1] == 'x' || value[1] == 'X'))
327 const int64 r = strto64(value, &end, base);
328 if (errno || end != value + strlen(value)) return false; // bad parse
329 if (static_cast<int32>(r) != r) // worked, but number out of range
331 SET_VALUE_AS(int32, static_cast<int32>(r));
335 while (*value == ' ') value++;
336 if (*value == '-') return false; // negative number
337 const uint64 r = strtou64(value, &end, base);
338 if (errno || end != value + strlen(value)) return false; // bad parse
339 if (static_cast<uint32>(r) != r) // worked, but number out of range
341 SET_VALUE_AS(uint32, static_cast<uint32>(r));
345 const int64 r = strto64(value, &end, base);
346 if (errno || end != value + strlen(value)) return false; // bad parse
347 SET_VALUE_AS(int64, r);
351 while (*value == ' ') value++;
352 if (*value == '-') return false; // negative number
353 const uint64 r = strtou64(value, &end, base);
354 if (errno || end != value + strlen(value)) return false; // bad parse
355 SET_VALUE_AS(uint64, r);
359 const double r = strtod(value, &end);
360 if (errno || end != value + strlen(value)) return false; // bad parse
361 SET_VALUE_AS(double, r);
365 assert(false); // unknown type
371 string FlagValue::ToString() const {
372 char intbuf[64]; // enough to hold even the biggest number
375 return VALUE_AS(bool) ? "true" : "false";
377 snprintf(intbuf, sizeof(intbuf), "%" PRId32, VALUE_AS(int32));
380 snprintf(intbuf, sizeof(intbuf), "%" PRIu32, VALUE_AS(uint32));
383 snprintf(intbuf, sizeof(intbuf), "%" PRId64, VALUE_AS(int64));
386 snprintf(intbuf, sizeof(intbuf), "%" PRIu64, VALUE_AS(uint64));
389 snprintf(intbuf, sizeof(intbuf), "%.17g", VALUE_AS(double));
392 return VALUE_AS(string);
395 return ""; // unknown type
399 bool FlagValue::Validate(const char* flagname,
400 ValidateFnProto validate_fn_proto) const {
403 return reinterpret_cast<bool (*)(const char*, bool)>(
404 validate_fn_proto)(flagname, VALUE_AS(bool));
406 return reinterpret_cast<bool (*)(const char*, int32)>(
407 validate_fn_proto)(flagname, VALUE_AS(int32));
409 return reinterpret_cast<bool (*)(const char*, uint32)>(
410 validate_fn_proto)(flagname, VALUE_AS(uint32));
412 return reinterpret_cast<bool (*)(const char*, int64)>(
413 validate_fn_proto)(flagname, VALUE_AS(int64));
415 return reinterpret_cast<bool (*)(const char*, uint64)>(
416 validate_fn_proto)(flagname, VALUE_AS(uint64));
418 return reinterpret_cast<bool (*)(const char*, double)>(
419 validate_fn_proto)(flagname, VALUE_AS(double));
421 return reinterpret_cast<bool (*)(const char*, const string&)>(
422 validate_fn_proto)(flagname, VALUE_AS(string));
424 assert(false); // unknown type
429 const char* FlagValue::TypeName() const {
430 static const char types[] =
438 if (type_ > FV_MAX_INDEX) {
442 // Directly indexing the strings in the 'types' string, each of them is 7 bytes long.
443 return &types[type_ * 7];
446 bool FlagValue::Equal(const FlagValue& x) const {
447 if (type_ != x.type_)
450 case FV_BOOL: return VALUE_AS(bool) == OTHER_VALUE_AS(x, bool);
451 case FV_INT32: return VALUE_AS(int32) == OTHER_VALUE_AS(x, int32);
452 case FV_UINT32: return VALUE_AS(uint32) == OTHER_VALUE_AS(x, uint32);
453 case FV_INT64: return VALUE_AS(int64) == OTHER_VALUE_AS(x, int64);
454 case FV_UINT64: return VALUE_AS(uint64) == OTHER_VALUE_AS(x, uint64);
455 case FV_DOUBLE: return VALUE_AS(double) == OTHER_VALUE_AS(x, double);
456 case FV_STRING: return VALUE_AS(string) == OTHER_VALUE_AS(x, string);
457 default: assert(false); return false; // unknown type
461 FlagValue* FlagValue::New() const {
463 case FV_BOOL: return new FlagValue(new bool(false), true);
464 case FV_INT32: return new FlagValue(new int32(0), true);
465 case FV_UINT32: return new FlagValue(new uint32(0), true);
466 case FV_INT64: return new FlagValue(new int64(0), true);
467 case FV_UINT64: return new FlagValue(new uint64(0), true);
468 case FV_DOUBLE: return new FlagValue(new double(0.0), true);
469 case FV_STRING: return new FlagValue(new string, true);
470 default: assert(false); return NULL; // unknown type
474 void FlagValue::CopyFrom(const FlagValue& x) {
475 assert(type_ == x.type_);
477 case FV_BOOL: SET_VALUE_AS(bool, OTHER_VALUE_AS(x, bool)); break;
478 case FV_INT32: SET_VALUE_AS(int32, OTHER_VALUE_AS(x, int32)); break;
479 case FV_UINT32: SET_VALUE_AS(uint32, OTHER_VALUE_AS(x, uint32)); break;
480 case FV_INT64: SET_VALUE_AS(int64, OTHER_VALUE_AS(x, int64)); break;
481 case FV_UINT64: SET_VALUE_AS(uint64, OTHER_VALUE_AS(x, uint64)); break;
482 case FV_DOUBLE: SET_VALUE_AS(double, OTHER_VALUE_AS(x, double)); break;
483 case FV_STRING: SET_VALUE_AS(string, OTHER_VALUE_AS(x, string)); break;
484 default: assert(false); // unknown type
488 int FlagValue::ValueSize() const {
489 if (type_ > FV_MAX_INDEX) {
490 assert(false); // unknown type
493 static const uint8 valuesize[] = {
502 return valuesize[type_];
505 // --------------------------------------------------------------------
507 // This represents a single flag, including its name, description,
508 // default value, and current value. Mostly this serves as a
509 // struct, though it also knows how to register itself.
510 // All CommandLineFlags are owned by a (exactly one)
511 // FlagRegistry. If you wish to modify fields in this class, you
512 // should acquire the FlagRegistry lock for the registry that owns
514 // --------------------------------------------------------------------
516 class CommandLineFlag {
518 // Note: we take over memory-ownership of current_val and default_val.
519 CommandLineFlag(const char* name, const char* help, const char* filename,
520 FlagValue* current_val, FlagValue* default_val);
523 const char* name() const { return name_; }
524 const char* help() const { return help_; }
525 const char* filename() const { return file_; }
526 const char* CleanFileName() const; // nixes irrelevant prefix such as homedir
527 string current_value() const { return current_->ToString(); }
528 string default_value() const { return defvalue_->ToString(); }
529 const char* type_name() const { return defvalue_->TypeName(); }
530 ValidateFnProto validate_function() const { return validate_fn_proto_; }
531 const void* flag_ptr() const { return current_->value_buffer_; }
533 FlagValue::ValueType Type() const { return defvalue_->Type(); }
535 void FillCommandLineFlagInfo(struct CommandLineFlagInfo* result);
537 // If validate_fn_proto_ is non-NULL, calls it on value, returns result.
538 bool Validate(const FlagValue& value) const;
539 bool ValidateCurrent() const { return Validate(*current_); }
540 bool Modified() const { return modified_; }
543 // for SetFlagLocked() and setting flags_by_ptr_
544 friend class FlagRegistry;
545 friend class GFLAGS_NAMESPACE::FlagSaverImpl; // for cloning the values
547 friend bool AddFlagValidator(const void*, ValidateFnProto);
549 // This copies all the non-const members: modified, processed, defvalue, etc.
550 void CopyFrom(const CommandLineFlag& src);
552 void UpdateModifiedBit();
554 const char* const name_; // Flag name
555 const char* const help_; // Help message
556 const char* const file_; // Which file did this come from?
557 bool modified_; // Set after default assignment?
558 FlagValue* defvalue_; // Default value for flag
559 FlagValue* current_; // Current value for flag
560 // This is a casted, 'generic' version of validate_fn, which actually
561 // takes a flag-value as an arg (void (*validate_fn)(bool), say).
562 // When we pass this to current_->Validate(), it will cast it back to
563 // the proper type. This may be NULL to mean we have no validate_fn.
564 ValidateFnProto validate_fn_proto_;
566 CommandLineFlag(const CommandLineFlag&); // no copying!
567 void operator=(const CommandLineFlag&);
570 CommandLineFlag::CommandLineFlag(const char* name, const char* help,
571 const char* filename,
572 FlagValue* current_val, FlagValue* default_val)
573 : name_(name), help_(help), file_(filename), modified_(false),
574 defvalue_(default_val), current_(current_val), validate_fn_proto_(NULL) {
577 CommandLineFlag::~CommandLineFlag() {
582 const char* CommandLineFlag::CleanFileName() const {
583 // This function has been used to strip off a common prefix from
584 // flag source file names. Because flags can be defined in different
585 // shared libraries, there may not be a single common prefix.
586 // Further, this functionality hasn't been active for many years.
587 // Need a better way to produce more user friendly help output or
588 // "anonymize" file paths in help output, respectively.
589 // Follow issue at: https://github.com/gflags/gflags/issues/86
593 void CommandLineFlag::FillCommandLineFlagInfo(
594 CommandLineFlagInfo* result) {
595 result->name = name();
596 result->type = type_name();
597 result->description = help();
598 result->current_value = current_value();
599 result->default_value = default_value();
600 result->filename = CleanFileName();
602 result->is_default = !modified_;
603 result->has_validator_fn = validate_function() != NULL;
604 result->flag_ptr = flag_ptr();
607 void CommandLineFlag::UpdateModifiedBit() {
608 // Update the "modified" bit in case somebody bypassed the
609 // Flags API and wrote directly through the FLAGS_name variable.
610 if (!modified_ && !current_->Equal(*defvalue_)) {
615 void CommandLineFlag::CopyFrom(const CommandLineFlag& src) {
616 // Note we only copy the non-const members; others are fixed at construct time
617 if (modified_ != src.modified_) modified_ = src.modified_;
618 if (!current_->Equal(*src.current_)) current_->CopyFrom(*src.current_);
619 if (!defvalue_->Equal(*src.defvalue_)) defvalue_->CopyFrom(*src.defvalue_);
620 if (validate_fn_proto_ != src.validate_fn_proto_)
621 validate_fn_proto_ = src.validate_fn_proto_;
624 bool CommandLineFlag::Validate(const FlagValue& value) const {
626 if (validate_function() == NULL)
629 return value.Validate(name(), validate_function());
633 // --------------------------------------------------------------------
635 // A FlagRegistry singleton object holds all flag objects indexed
636 // by their names so that if you know a flag's name (as a C
637 // string), you can access or set it. If the function is named
638 // FooLocked(), you must own the registry lock before calling
639 // the function; otherwise, you should *not* hold the lock, and
640 // the function will acquire it itself if needed.
641 // --------------------------------------------------------------------
643 struct StringCmp { // Used by the FlagRegistry map class to compare char*'s
644 bool operator() (const char* s1, const char* s2) const {
645 return (strcmp(s1, s2) < 0);
655 // Not using STLDeleteElements as that resides in util and this
657 for (FlagMap::iterator p = flags_.begin(), e = flags_.end(); p != e; ++p) {
658 CommandLineFlag* flag = p->second;
663 static void DeleteGlobalRegistry() {
664 delete global_registry_;
665 global_registry_ = NULL;
668 // Store a flag in this registry. Takes ownership of the given pointer.
669 void RegisterFlag(CommandLineFlag* flag);
671 void Lock() { lock_.Lock(); }
672 void Unlock() { lock_.Unlock(); }
674 // Returns the flag object for the specified name, or NULL if not found.
675 CommandLineFlag* FindFlagLocked(const char* name);
677 // Returns the flag object whose current-value is stored at flag_ptr.
678 // That is, for whom current_->value_buffer_ == flag_ptr
679 CommandLineFlag* FindFlagViaPtrLocked(const void* flag_ptr);
681 // A fancier form of FindFlag that works correctly if name is of the
682 // form flag=value. In that case, we set key to point to flag, and
683 // modify v to point to the value (if present), and return the flag
684 // with the given name. If the flag does not exist, returns NULL
685 // and sets error_message.
686 CommandLineFlag* SplitArgumentLocked(const char* argument,
687 string* key, const char** v,
688 string* error_message);
690 // Set the value of a flag. If the flag was successfully set to
691 // value, set msg to indicate the new flag-value, and return true.
692 // Otherwise, set msg to indicate the error, leave flag unchanged,
693 // and return false. msg can be NULL.
694 bool SetFlagLocked(CommandLineFlag* flag, const char* value,
695 FlagSettingMode set_mode, string* msg);
697 static FlagRegistry* GlobalRegistry(); // returns a singleton registry
700 friend class GFLAGS_NAMESPACE::FlagSaverImpl; // reads all the flags in order to copy them
701 friend class CommandLineFlagParser; // for ValidateUnmodifiedFlags
702 friend void GFLAGS_NAMESPACE::GetAllFlags(vector<CommandLineFlagInfo>*);
704 // The map from name to flag, for FindFlagLocked().
705 typedef map<const char*, CommandLineFlag*, StringCmp> FlagMap;
706 typedef FlagMap::iterator FlagIterator;
707 typedef FlagMap::const_iterator FlagConstIterator;
710 // The map from current-value pointer to flag, fo FindFlagViaPtrLocked().
711 typedef map<const void*, CommandLineFlag*> FlagPtrMap;
712 FlagPtrMap flags_by_ptr_;
714 static FlagRegistry* global_registry_; // a singleton registry
718 static void InitGlobalRegistry();
721 FlagRegistry(const FlagRegistry&);
722 FlagRegistry& operator=(const FlagRegistry&);
725 class FlagRegistryLock {
727 explicit FlagRegistryLock(FlagRegistry* fr) : fr_(fr) { fr_->Lock(); }
728 ~FlagRegistryLock() { fr_->Unlock(); }
730 FlagRegistry *const fr_;
734 void FlagRegistry::RegisterFlag(CommandLineFlag* flag) {
736 pair<FlagIterator, bool> ins =
737 flags_.insert(pair<const char*, CommandLineFlag*>(flag->name(), flag));
738 if (ins.second == false) { // means the name was already in the map
739 if (strcmp(ins.first->second->filename(), flag->filename()) != 0) {
740 ReportError(DIE, "ERROR: flag '%s' was defined more than once "
741 "(in files '%s' and '%s').\n",
743 ins.first->second->filename(),
746 ReportError(DIE, "ERROR: something wrong with flag '%s' in file '%s'. "
747 "One possibility: file '%s' is being linked both statically "
748 "and dynamically into this executable.\n",
750 flag->filename(), flag->filename());
753 // Also add to the flags_by_ptr_ map.
754 flags_by_ptr_[flag->current_->value_buffer_] = flag;
758 CommandLineFlag* FlagRegistry::FindFlagLocked(const char* name) {
759 FlagConstIterator i = flags_.find(name);
760 if (i == flags_.end()) {
761 // If the name has dashes in it, try again after replacing with
763 if (strchr(name, '-') == NULL) return NULL;
764 string name_rep = name;
765 std::replace(name_rep.begin(), name_rep.end(), '-', '_');
766 return FindFlagLocked(name_rep.c_str());
772 CommandLineFlag* FlagRegistry::FindFlagViaPtrLocked(const void* flag_ptr) {
773 FlagPtrMap::const_iterator i = flags_by_ptr_.find(flag_ptr);
774 if (i == flags_by_ptr_.end()) {
781 CommandLineFlag* FlagRegistry::SplitArgumentLocked(const char* arg,
784 string* error_message) {
785 // Find the flag object for this option
786 const char* flag_name;
787 const char* value = strchr(arg, '=');
792 // Strip out the "=value" portion from arg
793 key->assign(arg, value-arg);
794 *v = ++value; // advance past the '='
796 flag_name = key->c_str();
798 CommandLineFlag* flag = FindFlagLocked(flag_name);
801 // If we can't find the flag-name, then we should return an error.
802 // The one exception is if 1) the flag-name is 'nox', 2) there
803 // exists a flag named 'x', and 3) 'x' is a boolean flag.
804 // In that case, we want to return flag 'x'.
805 if (!(flag_name[0] == 'n' && flag_name[1] == 'o')) {
806 // flag-name is not 'nox', so we're not in the exception case.
807 *error_message = StringPrintf("%sunknown command line flag '%s'\n",
808 kError, key->c_str());
811 flag = FindFlagLocked(flag_name+2);
813 // No flag named 'x' exists, so we're not in the exception case.
814 *error_message = StringPrintf("%sunknown command line flag '%s'\n",
815 kError, key->c_str());
818 if (flag->Type() != FlagValue::FV_BOOL) {
819 // 'x' exists but is not boolean, so we're not in the exception case.
820 *error_message = StringPrintf(
821 "%sboolean value (%s) specified for %s command line flag\n",
822 kError, key->c_str(), flag->type_name());
825 // We're in the exception case!
826 // Make up a fake value to replace the "no" we stripped out
827 key->assign(flag_name+2); // the name without the "no"
831 // Assign a value if this is a boolean flag
832 if (*v == NULL && flag->Type() == FlagValue::FV_BOOL) {
833 *v = "1"; // the --nox case was already handled, so this is the --x case
839 bool TryParseLocked(const CommandLineFlag* flag, FlagValue* flag_value,
840 const char* value, string* msg) {
841 // Use tenative_value, not flag_value, until we know value is valid.
842 FlagValue* tentative_value = flag_value->New();
843 if (!tentative_value->ParseFrom(value)) {
846 "%sillegal value '%s' specified for %s flag '%s'\n",
848 flag->type_name(), flag->name());
850 delete tentative_value;
852 } else if (!flag->Validate(*tentative_value)) {
855 "%sfailed validation of new value '%s' for flag '%s'\n",
856 kError, tentative_value->ToString().c_str(),
859 delete tentative_value;
862 flag_value->CopyFrom(*tentative_value);
864 StringAppendF(msg, "%s set to %s\n",
865 flag->name(), flag_value->ToString().c_str());
867 delete tentative_value;
872 bool FlagRegistry::SetFlagLocked(CommandLineFlag* flag,
874 FlagSettingMode set_mode,
876 flag->UpdateModifiedBit();
878 case SET_FLAGS_VALUE: {
879 // set or modify the flag's value
880 if (!TryParseLocked(flag, flag->current_, value, msg))
882 flag->modified_ = true;
885 case SET_FLAG_IF_DEFAULT: {
886 // set the flag's value, but only if it hasn't been set by someone else
887 if (!flag->modified_) {
888 if (!TryParseLocked(flag, flag->current_, value, msg))
890 flag->modified_ = true;
892 *msg = StringPrintf("%s set to %s",
893 flag->name(), flag->current_value().c_str());
897 case SET_FLAGS_DEFAULT: {
898 // modify the flag's default-value
899 if (!TryParseLocked(flag, flag->defvalue_, value, msg))
901 if (!flag->modified_) {
902 // Need to set both defvalue *and* current, in this case
903 TryParseLocked(flag, flag->current_, value, NULL);
917 // Get the singleton FlagRegistry object
918 FlagRegistry* FlagRegistry::global_registry_ = NULL;
920 FlagRegistry* FlagRegistry::GlobalRegistry() {
921 static Mutex lock(Mutex::LINKER_INITIALIZED);
922 MutexLock acquire_lock(&lock);
923 if (!global_registry_) {
924 global_registry_ = new FlagRegistry;
926 return global_registry_;
929 // --------------------------------------------------------------------
930 // CommandLineFlagParser
931 // Parsing is done in two stages. In the first, we go through
932 // argv. For every flag-like arg we can make sense of, we parse
933 // it and set the appropriate FLAGS_* variable. For every flag-
934 // like arg we can't make sense of, we store it in a vector,
935 // along with an explanation of the trouble. In stage 2, we
936 // handle the 'reporting' flags like --help and --mpm_version.
937 // (This is via a call to HandleCommandLineHelpFlags(), in
938 // gflags_reporting.cc.)
939 // An optional stage 3 prints out the error messages.
940 // This is a bit of a simplification. For instance, --flagfile
941 // is handled as soon as it's seen in stage 1, not in stage 2.
942 // --------------------------------------------------------------------
944 class CommandLineFlagParser {
946 // The argument is the flag-registry to register the parsed flags in
947 explicit CommandLineFlagParser(FlagRegistry* reg) : registry_(reg) {}
948 ~CommandLineFlagParser() {}
950 // Stage 1: Every time this is called, it reads all flags in argv.
951 // However, it ignores all flags that have been successfully set
952 // before. Typically this is only called once, so this 'reparsing'
953 // behavior isn't important. It can be useful when trying to
954 // reparse after loading a dll, though.
955 uint32 ParseNewCommandLineFlags(int* argc, char*** argv, bool remove_flags);
957 // Stage 2: print reporting info and exit, if requested.
958 // In gflags_reporting.cc:HandleCommandLineHelpFlags().
960 // Stage 3: validate all the commandline flags that have validators
961 // registered and were not set/modified by ParseNewCommandLineFlags.
962 void ValidateFlags(bool all);
963 void ValidateAllFlags();
964 void ValidateUnmodifiedFlags();
966 // Stage 4: report any errors and return true if any were found.
969 // Set a particular command line option. "newval" is a string
970 // describing the new value that the option has been set to. If
971 // option_name does not specify a valid option name, or value is not
972 // a valid value for option_name, newval is empty. Does recursive
973 // processing for --flagfile and --fromenv. Returns the new value
974 // if everything went ok, or empty-string if not. (Actually, the
975 // return-string could hold many flag/value pairs due to --flagfile.)
976 // NB: Must have called registry_->Lock() before calling this function.
977 string ProcessSingleOptionLocked(CommandLineFlag* flag,
979 FlagSettingMode set_mode);
981 // Set a whole batch of command line options as specified by contentdata,
982 // which is in flagfile format (and probably has been read from a flagfile).
983 // Returns the new value if everything went ok, or empty-string if
984 // not. (Actually, the return-string could hold many flag/value
985 // pairs due to --flagfile.)
986 // NB: Must have called registry_->Lock() before calling this function.
987 string ProcessOptionsFromStringLocked(const string& contentdata,
988 FlagSettingMode set_mode);
990 // These are the 'recursive' flags, defined at the top of this file.
991 // Whenever we see these flags on the commandline, we must take action.
992 // These are called by ProcessSingleOptionLocked and, similarly, return
993 // new values if everything went ok, or the empty-string if not.
994 string ProcessFlagfileLocked(const string& flagval, FlagSettingMode set_mode);
995 // diff fromenv/tryfromenv
996 string ProcessFromenvLocked(const string& flagval, FlagSettingMode set_mode,
997 bool errors_are_fatal);
1000 FlagRegistry* const registry_;
1001 map<string, string> error_flags_; // map from name to error message
1002 // This could be a set<string>, but we reuse the map to minimize the .o size
1003 map<string, string> undefined_names_; // --[flag] name was not registered
1007 // Parse a list of (comma-separated) flags.
1008 static void ParseFlagList(const char* value, vector<string>* flags) {
1009 for (const char *p = value; p && *p; value = p) {
1010 p = strchr(value, ',');
1016 len = strlen(value);
1020 ReportError(DIE, "ERROR: empty flaglist entry\n");
1021 if (value[0] == '-')
1022 ReportError(DIE, "ERROR: flag \"%*s\" begins with '-'\n", len, value);
1024 flags->push_back(string(value, len));
1028 // Snarf an entire file into a C++ string. This is just so that we
1029 // can do all the I/O in one place and not worry about it everywhere.
1030 // Plus, it's convenient to have the whole file contents at hand.
1031 // Adds a newline at the end of the file.
1032 #define PFATAL(s) do { perror(s); gflags_exitfunc(1); } while (0)
1034 static string ReadFileIntoString(const char* filename) {
1035 const int kBufSize = 8092;
1036 char buffer[kBufSize];
1039 if ((errno = SafeFOpen(&fp, filename, "r")) != 0) PFATAL(filename);
1041 while ( (n=fread(buffer, 1, kBufSize, fp)) > 0 ) {
1042 if (ferror(fp)) PFATAL(filename);
1043 s.append(buffer, n);
1049 uint32 CommandLineFlagParser::ParseNewCommandLineFlags(int* argc, char*** argv,
1050 bool remove_flags) {
1051 int first_nonopt = *argc; // for non-options moved to the end
1054 for (int i = 1; i < first_nonopt; i++) {
1055 char* arg = (*argv)[i];
1057 // Like getopt(), we permute non-option flags to be at the end.
1058 if (arg[0] != '-' || // must be a program argument
1059 (arg[0] == '-' && arg[1] == '\0')) { // "-" is an argument, not a flag
1060 memmove((*argv) + i, (*argv) + i+1, (*argc - (i+1)) * sizeof((*argv)[i]));
1061 (*argv)[*argc-1] = arg; // we go last
1062 first_nonopt--; // we've been pushed onto the stack
1063 i--; // to undo the i++ in the loop
1067 if (arg[0] == '-') arg++; // allow leading '-'
1068 if (arg[0] == '-') arg++; // or leading '--'
1070 // -- alone means what it does for GNU: stop options parsing
1076 // Find the flag object for this option
1079 string error_message;
1080 CommandLineFlag* flag = registry_->SplitArgumentLocked(arg, &key, &value,
1083 undefined_names_[key] = ""; // value isn't actually used
1084 error_flags_[key] = error_message;
1088 if (value == NULL) {
1089 // Boolean options are always assigned a value by SplitArgumentLocked()
1090 assert(flag->Type() != FlagValue::FV_BOOL);
1091 if (i+1 >= first_nonopt) {
1092 // This flag needs a value, but there is nothing available
1093 error_flags_[key] = (string(kError) + "flag '" + (*argv)[i] + "'"
1094 + " is missing its argument");
1095 if (flag->help() && flag->help()[0] > '\001') {
1096 // Be useful in case we have a non-stripped description.
1097 error_flags_[key] += string("; flag description: ") + flag->help();
1099 error_flags_[key] += "\n";
1100 break; // we treat this as an unrecoverable error
1102 value = (*argv)[++i]; // read next arg for value
1104 // Heuristic to detect the case where someone treats a string arg
1106 // --my_string_var --foo=bar
1107 // We look for a flag of string type, whose value begins with a
1108 // dash, and where the flag-name and value are separated by a
1109 // space rather than an '='.
1110 // To avoid false positives, we also require the word "true"
1111 // or "false" in the help string. Without this, a valid usage
1112 // "-lat -30.5" would trigger the warning. The common cases we
1113 // want to solve talk about true and false as values.
1115 && flag->Type() == FlagValue::FV_STRING
1116 && (strstr(flag->help(), "true")
1117 || strstr(flag->help(), "false"))) {
1118 LOG(WARNING) << "Did you really mean to set flag '"
1119 << flag->name() << "' to the value '"
1125 // TODO(csilvers): only set a flag if we hadn't set it before here
1126 ProcessSingleOptionLocked(flag, value, SET_FLAGS_VALUE);
1128 registry_->Unlock();
1130 if (remove_flags) { // Fix up argc and argv by removing command line flags
1131 (*argv)[first_nonopt-1] = (*argv)[0];
1132 (*argv) += (first_nonopt-1);
1133 (*argc) -= (first_nonopt-1);
1134 first_nonopt = 1; // because we still don't count argv[0]
1137 logging_is_probably_set_up = true; // because we've parsed --logdir, etc.
1139 return first_nonopt;
1142 string CommandLineFlagParser::ProcessFlagfileLocked(const string& flagval,
1143 FlagSettingMode set_mode) {
1144 if (flagval.empty())
1148 vector<string> filename_list;
1149 ParseFlagList(flagval.c_str(), &filename_list); // take a list of filenames
1150 for (size_t i = 0; i < filename_list.size(); ++i) {
1151 const char* file = filename_list[i].c_str();
1152 msg += ProcessOptionsFromStringLocked(ReadFileIntoString(file), set_mode);
1157 string CommandLineFlagParser::ProcessFromenvLocked(const string& flagval,
1158 FlagSettingMode set_mode,
1159 bool errors_are_fatal) {
1160 if (flagval.empty())
1164 vector<string> flaglist;
1165 ParseFlagList(flagval.c_str(), &flaglist);
1167 for (size_t i = 0; i < flaglist.size(); ++i) {
1168 const char* flagname = flaglist[i].c_str();
1169 CommandLineFlag* flag = registry_->FindFlagLocked(flagname);
1171 error_flags_[flagname] =
1172 StringPrintf("%sunknown command line flag '%s' "
1173 "(via --fromenv or --tryfromenv)\n",
1175 undefined_names_[flagname] = "";
1179 const string envname = string("FLAGS_") + string(flagname);
1181 if (!SafeGetEnv(envname.c_str(), envval)) {
1182 if (errors_are_fatal) {
1183 error_flags_[flagname] = (string(kError) + envname +
1184 " not found in environment\n");
1189 // Avoid infinite recursion.
1190 if (envval == "fromenv" || envval == "tryfromenv") {
1191 error_flags_[flagname] =
1192 StringPrintf("%sinfinite recursion on environment flag '%s'\n",
1193 kError, envval.c_str());
1197 msg += ProcessSingleOptionLocked(flag, envval.c_str(), set_mode);
1202 string CommandLineFlagParser::ProcessSingleOptionLocked(
1203 CommandLineFlag* flag, const char* value, FlagSettingMode set_mode) {
1205 if (value && !registry_->SetFlagLocked(flag, value, set_mode, &msg)) {
1206 error_flags_[flag->name()] = msg;
1210 // The recursive flags, --flagfile and --fromenv and --tryfromenv,
1211 // must be dealt with as soon as they're seen. They will emit
1212 // messages of their own.
1213 if (strcmp(flag->name(), "flagfile") == 0) {
1214 msg += ProcessFlagfileLocked(FLAGS_flagfile, set_mode);
1216 } else if (strcmp(flag->name(), "fromenv") == 0) {
1217 // last arg indicates envval-not-found is fatal (unlike in --tryfromenv)
1218 msg += ProcessFromenvLocked(FLAGS_fromenv, set_mode, true);
1220 } else if (strcmp(flag->name(), "tryfromenv") == 0) {
1221 msg += ProcessFromenvLocked(FLAGS_tryfromenv, set_mode, false);
1227 void CommandLineFlagParser::ValidateFlags(bool all) {
1228 FlagRegistryLock frl(registry_);
1229 for (FlagRegistry::FlagConstIterator i = registry_->flags_.begin();
1230 i != registry_->flags_.end(); ++i) {
1231 if ((all || !i->second->Modified()) && !i->second->ValidateCurrent()) {
1232 // only set a message if one isn't already there. (If there's
1233 // an error message, our job is done, even if it's not exactly
1235 if (error_flags_[i->second->name()].empty()) {
1236 error_flags_[i->second->name()] =
1237 string(kError) + "--" + i->second->name() +
1238 " must be set on the commandline";
1239 if (!i->second->Modified()) {
1240 error_flags_[i->second->name()] += " (default value fails validation)";
1242 error_flags_[i->second->name()] += "\n";
1248 void CommandLineFlagParser::ValidateAllFlags() {
1249 ValidateFlags(true);
1252 void CommandLineFlagParser::ValidateUnmodifiedFlags() {
1253 ValidateFlags(false);
1256 bool CommandLineFlagParser::ReportErrors() {
1257 // error_flags_ indicates errors we saw while parsing.
1258 // But we ignore undefined-names if ok'ed by --undef_ok
1259 if (!FLAGS_undefok.empty()) {
1260 vector<string> flaglist;
1261 ParseFlagList(FLAGS_undefok.c_str(), &flaglist);
1262 for (size_t i = 0; i < flaglist.size(); ++i) {
1263 // We also deal with --no<flag>, in case the flagname was boolean
1264 const string no_version = string("no") + flaglist[i];
1265 if (undefined_names_.find(flaglist[i]) != undefined_names_.end()) {
1266 error_flags_[flaglist[i]] = ""; // clear the error message
1267 } else if (undefined_names_.find(no_version) != undefined_names_.end()) {
1268 error_flags_[no_version] = "";
1272 // Likewise, if they decided to allow reparsing, all undefined-names
1273 // are ok; we just silently ignore them now, and hope that a future
1274 // parse will pick them up somehow.
1275 if (allow_command_line_reparsing) {
1276 for (map<string, string>::const_iterator it = undefined_names_.begin();
1277 it != undefined_names_.end(); ++it)
1278 error_flags_[it->first] = ""; // clear the error message
1281 bool found_error = false;
1282 string error_message;
1283 for (map<string, string>::const_iterator it = error_flags_.begin();
1284 it != error_flags_.end(); ++it) {
1285 if (!it->second.empty()) {
1286 error_message.append(it->second.data(), it->second.size());
1291 ReportError(DO_NOT_DIE, "%s", error_message.c_str());
1295 string CommandLineFlagParser::ProcessOptionsFromStringLocked(
1296 const string& contentdata, FlagSettingMode set_mode) {
1298 const char* flagfile_contents = contentdata.c_str();
1299 bool flags_are_relevant = true; // set to false when filenames don't match
1300 bool in_filename_section = false;
1302 const char* line_end = flagfile_contents;
1303 // We read this file a line at a time.
1304 for (; line_end; flagfile_contents = line_end + 1) {
1305 while (*flagfile_contents && isspace(*flagfile_contents))
1306 ++flagfile_contents;
1307 // Windows uses "\r\n"
1308 line_end = strchr(flagfile_contents, '\r');
1309 if (line_end == NULL)
1310 line_end = strchr(flagfile_contents, '\n');
1312 size_t len = line_end ? line_end - flagfile_contents
1313 : strlen(flagfile_contents);
1314 string line(flagfile_contents, len);
1316 // Each line can be one of four things:
1317 // 1) A comment line -- we skip it
1318 // 2) An empty line -- we skip it
1319 // 3) A list of filenames -- starts a new filenames+flags section
1320 // 4) A --flag=value line -- apply if previous filenames match
1321 if (line.empty() || line[0] == '#') {
1322 // comment or empty line; just ignore
1324 } else if (line[0] == '-') { // flag
1325 in_filename_section = false; // instead, it was a flag-line
1326 if (!flags_are_relevant) // skip this flag; applies to someone else
1329 const char* name_and_val = line.c_str() + 1; // skip the leading -
1330 if (*name_and_val == '-')
1331 name_and_val++; // skip second - too
1334 string error_message;
1335 CommandLineFlag* flag = registry_->SplitArgumentLocked(name_and_val,
1338 // By API, errors parsing flagfile lines are silently ignored.
1340 // "WARNING: flagname '" + key + "' not found\n"
1341 } else if (value == NULL) {
1342 // "WARNING: flagname '" + key + "' missing a value\n"
1344 retval += ProcessSingleOptionLocked(flag, value, set_mode);
1347 } else { // a filename!
1348 if (!in_filename_section) { // start over: assume filenames don't match
1349 in_filename_section = true;
1350 flags_are_relevant = false;
1353 // Split the line up at spaces into glob-patterns
1354 const char* space = line.c_str(); // just has to be non-NULL
1355 for (const char* word = line.c_str(); *space; word = space+1) {
1356 if (flags_are_relevant) // we can stop as soon as we match
1358 space = strchr(word, ' ');
1360 space = word + strlen(word);
1361 const string glob(word, space - word);
1362 // We try matching both against the full argv0 and basename(argv0)
1363 if (glob == ProgramInvocationName() // small optimization
1364 || glob == ProgramInvocationShortName()
1365 #if defined(HAVE_FNMATCH_H)
1366 || fnmatch(glob.c_str(), ProgramInvocationName(), FNM_PATHNAME) == 0
1367 || fnmatch(glob.c_str(), ProgramInvocationShortName(), FNM_PATHNAME) == 0
1368 #elif defined(HAVE_SHLWAPI_H)
1369 || PathMatchSpec(glob.c_str(), ProgramInvocationName())
1370 || PathMatchSpec(glob.c_str(), ProgramInvocationShortName())
1373 flags_are_relevant = true;
1381 // --------------------------------------------------------------------
1383 // AddFlagValidator()
1384 // These are helper functions for routines like BoolFromEnv() and
1385 // RegisterFlagValidator, defined below. They're defined here so
1386 // they can live in the unnamed namespace (which makes friendship
1387 // declarations for these classes possible).
1388 // --------------------------------------------------------------------
1390 template<typename T>
1391 T GetFromEnv(const char *varname, T dflt) {
1393 if (SafeGetEnv(varname, valstr)) {
1394 FlagValue ifv(new T, true);
1395 if (!ifv.ParseFrom(valstr.c_str())) {
1396 ReportError(DIE, "ERROR: error parsing env variable '%s' with value '%s'\n",
1397 varname, valstr.c_str());
1399 return OTHER_VALUE_AS(ifv, T);
1403 bool AddFlagValidator(const void* flag_ptr, ValidateFnProto validate_fn_proto) {
1404 // We want a lock around this routine, in case two threads try to
1405 // add a validator (hopefully the same one!) at once. We could use
1406 // our own thread, but we need to loook at the registry anyway, so
1407 // we just steal that one.
1408 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1409 FlagRegistryLock frl(registry);
1410 // First, find the flag whose current-flag storage is 'flag'.
1411 // This is the CommandLineFlag whose current_->value_buffer_ == flag
1412 CommandLineFlag* flag = registry->FindFlagViaPtrLocked(flag_ptr);
1414 LOG(WARNING) << "Ignoring RegisterValidateFunction() for flag pointer "
1415 << flag_ptr << ": no flag found at that address";
1417 } else if (validate_fn_proto == flag->validate_function()) {
1418 return true; // ok to register the same function over and over again
1419 } else if (validate_fn_proto != NULL && flag->validate_function() != NULL) {
1420 LOG(WARNING) << "Ignoring RegisterValidateFunction() for flag '"
1421 << flag->name() << "': validate-fn already registered";
1424 flag->validate_fn_proto_ = validate_fn_proto;
1429 } // end unnamed namespaces
1432 // Now define the functions that are exported via the .h file
1434 // --------------------------------------------------------------------
1436 // This class exists merely to have a global constructor (the
1437 // kind that runs before main(), that goes an initializes each
1438 // flag that's been declared. Note that it's very important we
1439 // don't have a destructor that deletes flag_, because that would
1440 // cause us to delete current_storage/defvalue_storage as well,
1441 // which can cause a crash if anything tries to access the flag
1442 // values in a global destructor.
1443 // --------------------------------------------------------------------
1446 void RegisterCommandLineFlag(const char* name,
1448 const char* filename,
1450 FlagValue* defvalue) {
1453 // Importantly, flag_ will never be deleted, so storage is always good.
1454 CommandLineFlag* flag =
1455 new CommandLineFlag(name, help, filename, current, defvalue);
1456 FlagRegistry::GlobalRegistry()->RegisterFlag(flag); // default registry
1460 template <typename FlagType>
1461 FlagRegisterer::FlagRegisterer(const char* name,
1463 const char* filename,
1464 FlagType* current_storage,
1465 FlagType* defvalue_storage) {
1466 FlagValue* const current = new FlagValue(current_storage, false);
1467 FlagValue* const defvalue = new FlagValue(defvalue_storage, false);
1468 RegisterCommandLineFlag(name, help, filename, current, defvalue);
1471 // Force compiler to generate code for the given template specialization.
1472 #define INSTANTIATE_FLAG_REGISTERER_CTOR(type) \
1473 template GFLAGS_DLL_DECL FlagRegisterer::FlagRegisterer( \
1474 const char* name, const char* help, const char* filename, \
1475 type* current_storage, type* defvalue_storage)
1477 // Do this for all supported flag types.
1478 INSTANTIATE_FLAG_REGISTERER_CTOR(bool);
1479 INSTANTIATE_FLAG_REGISTERER_CTOR(int32);
1480 INSTANTIATE_FLAG_REGISTERER_CTOR(uint32);
1481 INSTANTIATE_FLAG_REGISTERER_CTOR(int64);
1482 INSTANTIATE_FLAG_REGISTERER_CTOR(uint64);
1483 INSTANTIATE_FLAG_REGISTERER_CTOR(double);
1484 INSTANTIATE_FLAG_REGISTERER_CTOR(std::string);
1486 #undef INSTANTIATE_FLAG_REGISTERER_CTOR
1488 // --------------------------------------------------------------------
1490 // The main way the FlagRegistry class exposes its data. This
1491 // returns, as strings, all the info about all the flags in
1492 // the main registry, sorted first by filename they are defined
1493 // in, and then by flagname.
1494 // --------------------------------------------------------------------
1496 struct FilenameFlagnameCmp {
1497 bool operator()(const CommandLineFlagInfo& a,
1498 const CommandLineFlagInfo& b) const {
1499 int cmp = strcmp(a.filename.c_str(), b.filename.c_str());
1501 cmp = strcmp(a.name.c_str(), b.name.c_str()); // secondary sort key
1506 void GetAllFlags(vector<CommandLineFlagInfo>* OUTPUT) {
1507 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1509 for (FlagRegistry::FlagConstIterator i = registry->flags_.begin();
1510 i != registry->flags_.end(); ++i) {
1511 CommandLineFlagInfo fi;
1512 i->second->FillCommandLineFlagInfo(&fi);
1513 OUTPUT->push_back(fi);
1516 // Now sort the flags, first by filename they occur in, then alphabetically
1517 sort(OUTPUT->begin(), OUTPUT->end(), FilenameFlagnameCmp());
1520 // --------------------------------------------------------------------
1525 // ProgramInvocationName()
1526 // ProgramInvocationShortName()
1527 // SetUsageMessage()
1529 // Functions to set and get argv. Typically the setter is called
1530 // by ParseCommandLineFlags. Also can get the ProgramUsage string,
1531 // set by SetUsageMessage.
1532 // --------------------------------------------------------------------
1534 // These values are not protected by a Mutex because they are normally
1535 // set only once during program startup.
1536 static string argv0("UNKNOWN"); // just the program name
1537 static string cmdline; // the entire command-line
1538 static string program_usage;
1539 static vector<string> argvs;
1540 static uint32 argv_sum = 0;
1542 void SetArgv(int argc, const char** argv) {
1543 static bool called_set_argv = false;
1544 if (called_set_argv) return;
1545 called_set_argv = true;
1547 assert(argc > 0); // every program has at least a name
1551 for (int i = 0; i < argc; i++) {
1552 if (i != 0) cmdline += " ";
1554 argvs.push_back(argv[i]);
1557 // Compute a simple sum of all the chars in argv
1559 for (string::const_iterator c = cmdline.begin(); c != cmdline.end(); ++c) {
1564 const vector<string>& GetArgvs() { return argvs; }
1565 const char* GetArgv() { return cmdline.c_str(); }
1566 const char* GetArgv0() { return argv0.c_str(); }
1567 uint32 GetArgvSum() { return argv_sum; }
1568 const char* ProgramInvocationName() { // like the GNU libc fn
1571 const char* ProgramInvocationShortName() { // like the GNU libc fn
1572 size_t pos = argv0.rfind('/');
1574 if (pos == string::npos) pos = argv0.rfind('\\');
1576 return (pos == string::npos ? argv0.c_str() : (argv0.c_str() + pos + 1));
1579 void SetUsageMessage(const string& usage) {
1580 program_usage = usage;
1583 const char* ProgramUsage() {
1584 if (program_usage.empty()) {
1585 return "Warning: SetUsageMessage() never called";
1587 return program_usage.c_str();
1590 // --------------------------------------------------------------------
1591 // SetVersionString()
1593 // --------------------------------------------------------------------
1595 static string version_string;
1597 void SetVersionString(const string& version) {
1598 version_string = version;
1601 const char* VersionString() {
1602 return version_string.c_str();
1606 // --------------------------------------------------------------------
1607 // GetCommandLineOption()
1608 // GetCommandLineFlagInfo()
1609 // GetCommandLineFlagInfoOrDie()
1610 // SetCommandLineOption()
1611 // SetCommandLineOptionWithMode()
1612 // The programmatic way to set a flag's value, using a string
1613 // for its name rather than the variable itself (that is,
1614 // SetCommandLineOption("foo", x) rather than FLAGS_foo = x).
1615 // There's also a bit more flexibility here due to the various
1616 // set-modes, but typically these are used when you only have
1617 // that flag's name as a string, perhaps at runtime.
1618 // All of these work on the default, global registry.
1619 // For GetCommandLineOption, return false if no such flag
1620 // is known, true otherwise. We clear "value" if a suitable
1622 // --------------------------------------------------------------------
1625 bool GetCommandLineOption(const char* name, string* value) {
1630 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1631 FlagRegistryLock frl(registry);
1632 CommandLineFlag* flag = registry->FindFlagLocked(name);
1636 *value = flag->current_value();
1641 bool GetCommandLineFlagInfo(const char* name, CommandLineFlagInfo* OUTPUT) {
1642 if (NULL == name) return false;
1643 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1644 FlagRegistryLock frl(registry);
1645 CommandLineFlag* flag = registry->FindFlagLocked(name);
1650 flag->FillCommandLineFlagInfo(OUTPUT);
1655 CommandLineFlagInfo GetCommandLineFlagInfoOrDie(const char* name) {
1656 CommandLineFlagInfo info;
1657 if (!GetCommandLineFlagInfo(name, &info)) {
1658 fprintf(stderr, "FATAL ERROR: flag name '%s' doesn't exist\n", name);
1659 gflags_exitfunc(1); // almost certainly gflags_exitfunc()
1664 string SetCommandLineOptionWithMode(const char* name, const char* value,
1665 FlagSettingMode set_mode) {
1667 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1668 FlagRegistryLock frl(registry);
1669 CommandLineFlag* flag = registry->FindFlagLocked(name);
1671 CommandLineFlagParser parser(registry);
1672 result = parser.ProcessSingleOptionLocked(flag, value, set_mode);
1673 if (!result.empty()) { // in the error case, we've already logged
1674 // Could consider logging this change
1677 // The API of this function is that we return empty string on error
1681 string SetCommandLineOption(const char* name, const char* value) {
1682 return SetCommandLineOptionWithMode(name, value, SET_FLAGS_VALUE);
1685 // --------------------------------------------------------------------
1688 // This class stores the states of all flags at construct time,
1689 // and restores all flags to that state at destruct time.
1690 // Its major implementation challenge is that it never modifies
1691 // pointers in the 'main' registry, so global FLAG_* vars always
1692 // point to the right place.
1693 // --------------------------------------------------------------------
1695 class FlagSaverImpl {
1697 // Constructs an empty FlagSaverImpl object.
1698 explicit FlagSaverImpl(FlagRegistry* main_registry)
1699 : main_registry_(main_registry) { }
1701 // reclaim memory from each of our CommandLineFlags
1702 vector<CommandLineFlag*>::const_iterator it;
1703 for (it = backup_registry_.begin(); it != backup_registry_.end(); ++it)
1707 // Saves the flag states from the flag registry into this object.
1708 // It's an error to call this more than once.
1709 // Must be called when the registry mutex is not held.
1710 void SaveFromRegistry() {
1711 FlagRegistryLock frl(main_registry_);
1712 assert(backup_registry_.empty()); // call only once!
1713 for (FlagRegistry::FlagConstIterator it = main_registry_->flags_.begin();
1714 it != main_registry_->flags_.end();
1716 const CommandLineFlag* main = it->second;
1717 // Sets up all the const variables in backup correctly
1718 CommandLineFlag* backup = new CommandLineFlag(
1719 main->name(), main->help(), main->filename(),
1720 main->current_->New(), main->defvalue_->New());
1721 // Sets up all the non-const variables in backup correctly
1722 backup->CopyFrom(*main);
1723 backup_registry_.push_back(backup); // add it to a convenient list
1727 // Restores the saved flag states into the flag registry. We
1728 // assume no flags were added or deleted from the registry since
1729 // the SaveFromRegistry; if they were, that's trouble! Must be
1730 // called when the registry mutex is not held.
1731 void RestoreToRegistry() {
1732 FlagRegistryLock frl(main_registry_);
1733 vector<CommandLineFlag*>::const_iterator it;
1734 for (it = backup_registry_.begin(); it != backup_registry_.end(); ++it) {
1735 CommandLineFlag* main = main_registry_->FindFlagLocked((*it)->name());
1736 if (main != NULL) { // if NULL, flag got deleted from registry(!)
1737 main->CopyFrom(**it);
1743 FlagRegistry* const main_registry_;
1744 vector<CommandLineFlag*> backup_registry_;
1746 FlagSaverImpl(const FlagSaverImpl&); // no copying!
1747 void operator=(const FlagSaverImpl&);
1750 FlagSaver::FlagSaver()
1751 : impl_(new FlagSaverImpl(FlagRegistry::GlobalRegistry())) {
1752 impl_->SaveFromRegistry();
1755 FlagSaver::~FlagSaver() {
1756 impl_->RestoreToRegistry();
1761 // --------------------------------------------------------------------
1762 // CommandlineFlagsIntoString()
1763 // ReadFlagsFromString()
1764 // AppendFlagsIntoFile()
1765 // ReadFromFlagsFile()
1766 // These are mostly-deprecated routines that stick the
1767 // commandline flags into a file/string and read them back
1768 // out again. I can see a use for CommandlineFlagsIntoString,
1769 // for creating a flagfile, but the rest don't seem that useful
1770 // -- some, I think, are a poor-man's attempt at FlagSaver --
1771 // and are included only until we can delete them from callers.
1772 // Note they don't save --flagfile flags (though they do save
1773 // the result of having called the flagfile, of course).
1774 // --------------------------------------------------------------------
1776 static string TheseCommandlineFlagsIntoString(
1777 const vector<CommandLineFlagInfo>& flags) {
1778 vector<CommandLineFlagInfo>::const_iterator i;
1780 size_t retval_space = 0;
1781 for (i = flags.begin(); i != flags.end(); ++i) {
1782 // An (over)estimate of how much space it will take to print this flag
1783 retval_space += i->name.length() + i->current_value.length() + 5;
1787 retval.reserve(retval_space);
1788 for (i = flags.begin(); i != flags.end(); ++i) {
1792 retval += i->current_value;
1798 string CommandlineFlagsIntoString() {
1799 vector<CommandLineFlagInfo> sorted_flags;
1800 GetAllFlags(&sorted_flags);
1801 return TheseCommandlineFlagsIntoString(sorted_flags);
1804 bool ReadFlagsFromString(const string& flagfilecontents,
1805 const char* /*prog_name*/, // TODO(csilvers): nix this
1806 bool errors_are_fatal) {
1807 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1808 FlagSaverImpl saved_states(registry);
1809 saved_states.SaveFromRegistry();
1811 CommandLineFlagParser parser(registry);
1813 parser.ProcessOptionsFromStringLocked(flagfilecontents, SET_FLAGS_VALUE);
1815 // Should we handle --help and such when reading flags from a string? Sure.
1816 HandleCommandLineHelpFlags();
1817 if (parser.ReportErrors()) {
1818 // Error. Restore all global flags to their previous values.
1819 if (errors_are_fatal)
1821 saved_states.RestoreToRegistry();
1827 // TODO(csilvers): nix prog_name in favor of ProgramInvocationShortName()
1828 bool AppendFlagsIntoFile(const string& filename, const char *prog_name) {
1830 if (SafeFOpen(&fp, filename.c_str(), "a") != 0) {
1835 fprintf(fp, "%s\n", prog_name);
1837 vector<CommandLineFlagInfo> flags;
1838 GetAllFlags(&flags);
1839 // But we don't want --flagfile, which leads to weird recursion issues
1840 vector<CommandLineFlagInfo>::iterator i;
1841 for (i = flags.begin(); i != flags.end(); ++i) {
1842 if (strcmp(i->name.c_str(), "flagfile") == 0) {
1847 fprintf(fp, "%s", TheseCommandlineFlagsIntoString(flags).c_str());
1853 bool ReadFromFlagsFile(const string& filename, const char* prog_name,
1854 bool errors_are_fatal) {
1855 return ReadFlagsFromString(ReadFileIntoString(filename.c_str()),
1856 prog_name, errors_are_fatal);
1860 // --------------------------------------------------------------------
1868 // Reads the value from the environment and returns it.
1869 // We use an FlagValue to make the parsing easy.
1871 // DEFINE_bool(myflag, BoolFromEnv("MYFLAG_DEFAULT", false), "whatever");
1872 // --------------------------------------------------------------------
1874 bool BoolFromEnv(const char *v, bool dflt) {
1875 return GetFromEnv(v, dflt);
1877 int32 Int32FromEnv(const char *v, int32 dflt) {
1878 return GetFromEnv(v, dflt);
1880 uint32 Uint32FromEnv(const char *v, uint32 dflt) {
1881 return GetFromEnv(v, dflt);
1883 int64 Int64FromEnv(const char *v, int64 dflt) {
1884 return GetFromEnv(v, dflt);
1886 uint64 Uint64FromEnv(const char *v, uint64 dflt) {
1887 return GetFromEnv(v, dflt);
1889 double DoubleFromEnv(const char *v, double dflt) {
1890 return GetFromEnv(v, dflt);
1894 # pragma warning(push)
1895 # pragma warning(disable: 4996) // ignore getenv security warning
1897 const char *StringFromEnv(const char *varname, const char *dflt) {
1898 const char* const val = getenv(varname);
1899 return val ? val : dflt;
1902 # pragma warning(pop)
1906 // --------------------------------------------------------------------
1907 // RegisterFlagValidator()
1908 // RegisterFlagValidator() is the function that clients use to
1909 // 'decorate' a flag with a validation function. Once this is
1910 // done, every time the flag is set (including when the flag
1911 // is parsed from argv), the validator-function is called.
1912 // These functions return true if the validator was added
1913 // successfully, or false if not: the flag already has a validator,
1914 // (only one allowed per flag), the 1st arg isn't a flag, etc.
1915 // This function is not thread-safe.
1916 // --------------------------------------------------------------------
1918 bool RegisterFlagValidator(const bool* flag,
1919 bool (*validate_fn)(const char*, bool)) {
1920 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1922 bool RegisterFlagValidator(const int32* flag,
1923 bool (*validate_fn)(const char*, int32)) {
1924 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1926 bool RegisterFlagValidator(const uint32* flag,
1927 bool (*validate_fn)(const char*, uint32)) {
1928 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1930 bool RegisterFlagValidator(const int64* flag,
1931 bool (*validate_fn)(const char*, int64)) {
1932 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1934 bool RegisterFlagValidator(const uint64* flag,
1935 bool (*validate_fn)(const char*, uint64)) {
1936 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1938 bool RegisterFlagValidator(const double* flag,
1939 bool (*validate_fn)(const char*, double)) {
1940 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1942 bool RegisterFlagValidator(const string* flag,
1943 bool (*validate_fn)(const char*, const string&)) {
1944 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1948 // --------------------------------------------------------------------
1949 // ParseCommandLineFlags()
1950 // ParseCommandLineNonHelpFlags()
1951 // HandleCommandLineHelpFlags()
1952 // This is the main function called from main(), to actually
1953 // parse the commandline. It modifies argc and argv as described
1954 // at the top of gflags.h. You can also divide this
1955 // function into two parts, if you want to do work between
1956 // the parsing of the flags and the printing of any help output.
1957 // --------------------------------------------------------------------
1959 static uint32 ParseCommandLineFlagsInternal(int* argc, char*** argv,
1960 bool remove_flags, bool do_report) {
1961 SetArgv(*argc, const_cast<const char**>(*argv)); // save it for later
1963 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1964 CommandLineFlagParser parser(registry);
1966 // When we parse the commandline flags, we'll handle --flagfile,
1967 // --tryfromenv, etc. as we see them (since flag-evaluation order
1968 // may be important). But sometimes apps set FLAGS_tryfromenv/etc.
1969 // manually before calling ParseCommandLineFlags. We want to evaluate
1970 // those too, as if they were the first flags on the commandline.
1972 parser.ProcessFlagfileLocked(FLAGS_flagfile, SET_FLAGS_VALUE);
1973 // Last arg here indicates whether flag-not-found is a fatal error or not
1974 parser.ProcessFromenvLocked(FLAGS_fromenv, SET_FLAGS_VALUE, true);
1975 parser.ProcessFromenvLocked(FLAGS_tryfromenv, SET_FLAGS_VALUE, false);
1978 // Now get the flags specified on the commandline
1979 const int r = parser.ParseNewCommandLineFlags(argc, argv, remove_flags);
1982 HandleCommandLineHelpFlags(); // may cause us to exit on --help, etc.
1984 // See if any of the unset flags fail their validation checks
1985 parser.ValidateUnmodifiedFlags();
1987 if (parser.ReportErrors()) // may cause us to exit on illegal flags
1992 uint32 ParseCommandLineFlags(int* argc, char*** argv, bool remove_flags) {
1993 return ParseCommandLineFlagsInternal(argc, argv, remove_flags, true);
1996 uint32 ParseCommandLineNonHelpFlags(int* argc, char*** argv,
1997 bool remove_flags) {
1998 return ParseCommandLineFlagsInternal(argc, argv, remove_flags, false);
2001 // --------------------------------------------------------------------
2002 // AllowCommandLineReparsing()
2003 // ReparseCommandLineNonHelpFlags()
2004 // This is most useful for shared libraries. The idea is if
2005 // a flag is defined in a shared library that is dlopen'ed
2006 // sometime after main(), you can ParseCommandLineFlags before
2007 // the dlopen, then ReparseCommandLineNonHelpFlags() after the
2008 // dlopen, to get the new flags. But you have to explicitly
2009 // Allow() it; otherwise, you get the normal default behavior
2010 // of unrecognized flags calling a fatal error.
2011 // TODO(csilvers): this isn't used. Just delete it?
2012 // --------------------------------------------------------------------
2014 void AllowCommandLineReparsing() {
2015 allow_command_line_reparsing = true;
2018 void ReparseCommandLineNonHelpFlags() {
2019 // We make a copy of argc and argv to pass in
2020 const vector<string>& argvs = GetArgvs();
2021 int tmp_argc = static_cast<int>(argvs.size());
2022 char** tmp_argv = new char* [tmp_argc + 1];
2023 for (int i = 0; i < tmp_argc; ++i)
2024 tmp_argv[i] = strdup(argvs[i].c_str()); // TODO(csilvers): don't dup
2026 ParseCommandLineNonHelpFlags(&tmp_argc, &tmp_argv, false);
2028 for (int i = 0; i < tmp_argc; ++i)
2033 void ShutDownCommandLineFlags() {
2034 FlagRegistry::DeleteGlobalRegistry();
2038 } // namespace GFLAGS_NAMESPACE