1 // Copyright (c) 1999, Google Inc.
2 // All rights reserved.
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
8 // * Redistributions of source code must retain the above copyright
9 // notice, this list of conditions and the following disclaimer.
10 // * Redistributions in binary form must reproduce the above
11 // copyright notice, this list of conditions and the following disclaimer
12 // in the documentation and/or other materials provided with the
14 // * Neither the name of Google Inc. nor the names of its
15 // contributors may be used to endorse or promote products derived from
16 // this software without specific prior written permission.
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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);
229 // Calls the given validate-fn on value_buffer_, and returns
230 // whatever it returns. But first casts validate_fn_proto to a
231 // function that takes our value as an argument (eg void
232 // (*validate_fn)(bool) for a bool flag).
233 bool Validate(const char* flagname, ValidateFnProto validate_fn_proto) const;
235 void* const value_buffer_; // points to the buffer holding our data
236 const int8 type_; // how to interpret value_
237 const bool owns_value_; // whether to free value on destruct
239 FlagValue(const FlagValue&); // no copying!
240 void operator=(const FlagValue&);
243 // Map the given C++ type to a value of the ValueType enum at compile time.
244 #define DEFINE_FLAG_TRAITS(type, value) \
246 struct FlagValue::FlagValueTraits<type> { \
247 static const ValueType kValueType = value; \
250 // Define full template specializations of the FlagValueTraits template
251 // for all supported flag types.
252 DEFINE_FLAG_TRAITS(bool, FV_BOOL);
253 DEFINE_FLAG_TRAITS(int32, FV_INT32);
254 DEFINE_FLAG_TRAITS(uint32, FV_UINT32);
255 DEFINE_FLAG_TRAITS(int64, FV_INT64);
256 DEFINE_FLAG_TRAITS(uint64, FV_UINT64);
257 DEFINE_FLAG_TRAITS(double, FV_DOUBLE);
258 DEFINE_FLAG_TRAITS(std::string, FV_STRING);
260 #undef DEFINE_FLAG_TRAITS
263 // This could be a templated method of FlagValue, but doing so adds to the
264 // size of the .o. Since there's no type-safety here anyway, macro is ok.
265 #define VALUE_AS(type) *reinterpret_cast<type*>(value_buffer_)
266 #define OTHER_VALUE_AS(fv, type) *reinterpret_cast<type*>(fv.value_buffer_)
267 #define SET_VALUE_AS(type, value) VALUE_AS(type) = (value)
269 template <typename FlagType>
270 FlagValue::FlagValue(FlagType* valbuf,
271 bool transfer_ownership_of_value)
272 : value_buffer_(valbuf),
273 type_(FlagValueTraits<FlagType>::kValueType),
274 owns_value_(transfer_ownership_of_value) {
277 FlagValue::~FlagValue() {
282 case FV_BOOL: delete reinterpret_cast<bool*>(value_buffer_); break;
283 case FV_INT32: delete reinterpret_cast<int32*>(value_buffer_); break;
284 case FV_UINT32: delete reinterpret_cast<uint32*>(value_buffer_); break;
285 case FV_INT64: delete reinterpret_cast<int64*>(value_buffer_); break;
286 case FV_UINT64: delete reinterpret_cast<uint64*>(value_buffer_); break;
287 case FV_DOUBLE: delete reinterpret_cast<double*>(value_buffer_); break;
288 case FV_STRING: delete reinterpret_cast<string*>(value_buffer_); break;
292 bool FlagValue::ParseFrom(const char* value) {
293 if (type_ == FV_BOOL) {
294 const char* kTrue[] = { "1", "t", "true", "y", "yes" };
295 const char* kFalse[] = { "0", "f", "false", "n", "no" };
296 COMPILE_ASSERT(sizeof(kTrue) == sizeof(kFalse), true_false_equal);
297 for (size_t i = 0; i < sizeof(kTrue)/sizeof(*kTrue); ++i) {
298 if (strcasecmp(value, kTrue[i]) == 0) {
299 SET_VALUE_AS(bool, true);
301 } else if (strcasecmp(value, kFalse[i]) == 0) {
302 SET_VALUE_AS(bool, false);
306 return false; // didn't match a legal input
308 } else if (type_ == FV_STRING) {
309 SET_VALUE_AS(string, value);
313 // OK, it's likely to be numeric, and we'll be using a strtoXXX method.
314 if (value[0] == '\0') // empty-string is only allowed for string type.
317 // Leading 0x puts us in base 16. But leading 0 does not put us in base 8!
318 // It caused too many bugs when we had that behavior.
319 int base = 10; // by default
320 if (value[0] == '0' && (value[1] == 'x' || value[1] == 'X'))
326 const int64 r = strto64(value, &end, base);
327 if (errno || end != value + strlen(value)) return false; // bad parse
328 if (static_cast<int32>(r) != r) // worked, but number out of range
330 SET_VALUE_AS(int32, static_cast<int32>(r));
334 while (*value == ' ') value++;
335 if (*value == '-') return false; // negative number
336 const uint64 r = strtou64(value, &end, base);
337 if (errno || end != value + strlen(value)) return false; // bad parse
338 if (static_cast<uint32>(r) != r) // worked, but number out of range
340 SET_VALUE_AS(uint32, static_cast<uint32>(r));
344 const int64 r = strto64(value, &end, base);
345 if (errno || end != value + strlen(value)) return false; // bad parse
346 SET_VALUE_AS(int64, r);
350 while (*value == ' ') value++;
351 if (*value == '-') return false; // negative number
352 const uint64 r = strtou64(value, &end, base);
353 if (errno || end != value + strlen(value)) return false; // bad parse
354 SET_VALUE_AS(uint64, r);
358 const double r = strtod(value, &end);
359 if (errno || end != value + strlen(value)) return false; // bad parse
360 SET_VALUE_AS(double, r);
364 assert(false); // unknown type
370 string FlagValue::ToString() const {
371 char intbuf[64]; // enough to hold even the biggest number
374 return VALUE_AS(bool) ? "true" : "false";
376 snprintf(intbuf, sizeof(intbuf), "%" PRId32, VALUE_AS(int32));
379 snprintf(intbuf, sizeof(intbuf), "%" PRIu32, VALUE_AS(uint32));
382 snprintf(intbuf, sizeof(intbuf), "%" PRId64, VALUE_AS(int64));
385 snprintf(intbuf, sizeof(intbuf), "%" PRIu64, VALUE_AS(uint64));
388 snprintf(intbuf, sizeof(intbuf), "%.17g", VALUE_AS(double));
391 return VALUE_AS(string);
394 return ""; // unknown type
398 bool FlagValue::Validate(const char* flagname,
399 ValidateFnProto validate_fn_proto) const {
402 return reinterpret_cast<bool (*)(const char*, bool)>(
403 validate_fn_proto)(flagname, VALUE_AS(bool));
405 return reinterpret_cast<bool (*)(const char*, int32)>(
406 validate_fn_proto)(flagname, VALUE_AS(int32));
408 return reinterpret_cast<bool (*)(const char*, uint32)>(
409 validate_fn_proto)(flagname, VALUE_AS(uint32));
411 return reinterpret_cast<bool (*)(const char*, int64)>(
412 validate_fn_proto)(flagname, VALUE_AS(int64));
414 return reinterpret_cast<bool (*)(const char*, uint64)>(
415 validate_fn_proto)(flagname, VALUE_AS(uint64));
417 return reinterpret_cast<bool (*)(const char*, double)>(
418 validate_fn_proto)(flagname, VALUE_AS(double));
420 return reinterpret_cast<bool (*)(const char*, const string&)>(
421 validate_fn_proto)(flagname, VALUE_AS(string));
423 assert(false); // unknown type
428 const char* FlagValue::TypeName() const {
429 static const char types[] =
437 if (type_ > FV_MAX_INDEX) {
441 // Directly indexing the strings in the 'types' string, each of them is 7 bytes long.
442 return &types[type_ * 7];
445 bool FlagValue::Equal(const FlagValue& x) const {
446 if (type_ != x.type_)
449 case FV_BOOL: return VALUE_AS(bool) == OTHER_VALUE_AS(x, bool);
450 case FV_INT32: return VALUE_AS(int32) == OTHER_VALUE_AS(x, int32);
451 case FV_UINT32: return VALUE_AS(uint32) == OTHER_VALUE_AS(x, uint32);
452 case FV_INT64: return VALUE_AS(int64) == OTHER_VALUE_AS(x, int64);
453 case FV_UINT64: return VALUE_AS(uint64) == OTHER_VALUE_AS(x, uint64);
454 case FV_DOUBLE: return VALUE_AS(double) == OTHER_VALUE_AS(x, double);
455 case FV_STRING: return VALUE_AS(string) == OTHER_VALUE_AS(x, string);
456 default: assert(false); return false; // unknown type
460 FlagValue* FlagValue::New() const {
462 case FV_BOOL: return new FlagValue(new bool(false), true);
463 case FV_INT32: return new FlagValue(new int32(0), true);
464 case FV_UINT32: return new FlagValue(new uint32(0), true);
465 case FV_INT64: return new FlagValue(new int64(0), true);
466 case FV_UINT64: return new FlagValue(new uint64(0), true);
467 case FV_DOUBLE: return new FlagValue(new double(0.0), true);
468 case FV_STRING: return new FlagValue(new string, true);
469 default: assert(false); return NULL; // unknown type
473 void FlagValue::CopyFrom(const FlagValue& x) {
474 assert(type_ == x.type_);
476 case FV_BOOL: SET_VALUE_AS(bool, OTHER_VALUE_AS(x, bool)); break;
477 case FV_INT32: SET_VALUE_AS(int32, OTHER_VALUE_AS(x, int32)); break;
478 case FV_UINT32: SET_VALUE_AS(uint32, OTHER_VALUE_AS(x, uint32)); break;
479 case FV_INT64: SET_VALUE_AS(int64, OTHER_VALUE_AS(x, int64)); break;
480 case FV_UINT64: SET_VALUE_AS(uint64, OTHER_VALUE_AS(x, uint64)); break;
481 case FV_DOUBLE: SET_VALUE_AS(double, OTHER_VALUE_AS(x, double)); break;
482 case FV_STRING: SET_VALUE_AS(string, OTHER_VALUE_AS(x, string)); break;
483 default: assert(false); // unknown type
487 // --------------------------------------------------------------------
489 // This represents a single flag, including its name, description,
490 // default value, and current value. Mostly this serves as a
491 // struct, though it also knows how to register itself.
492 // All CommandLineFlags are owned by a (exactly one)
493 // FlagRegistry. If you wish to modify fields in this class, you
494 // should acquire the FlagRegistry lock for the registry that owns
496 // --------------------------------------------------------------------
498 class CommandLineFlag {
500 // Note: we take over memory-ownership of current_val and default_val.
501 CommandLineFlag(const char* name, const char* help, const char* filename,
502 FlagValue* current_val, FlagValue* default_val);
505 const char* name() const { return name_; }
506 const char* help() const { return help_; }
507 const char* filename() const { return file_; }
508 const char* CleanFileName() const; // nixes irrelevant prefix such as homedir
509 string current_value() const { return current_->ToString(); }
510 string default_value() const { return defvalue_->ToString(); }
511 const char* type_name() const { return defvalue_->TypeName(); }
512 ValidateFnProto validate_function() const { return validate_fn_proto_; }
513 const void* flag_ptr() const { return current_->value_buffer_; }
515 FlagValue::ValueType Type() const { return defvalue_->Type(); }
517 void FillCommandLineFlagInfo(struct CommandLineFlagInfo* result);
519 // If validate_fn_proto_ is non-NULL, calls it on value, returns result.
520 bool Validate(const FlagValue& value) const;
521 bool ValidateCurrent() const { return Validate(*current_); }
522 bool Modified() const { return modified_; }
525 // for SetFlagLocked() and setting flags_by_ptr_
526 friend class FlagRegistry;
527 friend class GFLAGS_NAMESPACE::FlagSaverImpl; // for cloning the values
529 friend bool AddFlagValidator(const void*, ValidateFnProto);
531 // This copies all the non-const members: modified, processed, defvalue, etc.
532 void CopyFrom(const CommandLineFlag& src);
534 void UpdateModifiedBit();
536 const char* const name_; // Flag name
537 const char* const help_; // Help message
538 const char* const file_; // Which file did this come from?
539 bool modified_; // Set after default assignment?
540 FlagValue* defvalue_; // Default value for flag
541 FlagValue* current_; // Current value for flag
542 // This is a casted, 'generic' version of validate_fn, which actually
543 // takes a flag-value as an arg (void (*validate_fn)(bool), say).
544 // When we pass this to current_->Validate(), it will cast it back to
545 // the proper type. This may be NULL to mean we have no validate_fn.
546 ValidateFnProto validate_fn_proto_;
548 CommandLineFlag(const CommandLineFlag&); // no copying!
549 void operator=(const CommandLineFlag&);
552 CommandLineFlag::CommandLineFlag(const char* name, const char* help,
553 const char* filename,
554 FlagValue* current_val, FlagValue* default_val)
555 : name_(name), help_(help), file_(filename), modified_(false),
556 defvalue_(default_val), current_(current_val), validate_fn_proto_(NULL) {
559 CommandLineFlag::~CommandLineFlag() {
564 const char* CommandLineFlag::CleanFileName() const {
565 // This function has been used to strip off a common prefix from
566 // flag source file names. Because flags can be defined in different
567 // shared libraries, there may not be a single common prefix.
568 // Further, this functionality hasn't been active for many years.
569 // Need a better way to produce more user friendly help output or
570 // "anonymize" file paths in help output, respectively.
571 // Follow issue at: https://github.com/gflags/gflags/issues/86
575 void CommandLineFlag::FillCommandLineFlagInfo(
576 CommandLineFlagInfo* result) {
577 result->name = name();
578 result->type = type_name();
579 result->description = help();
580 result->current_value = current_value();
581 result->default_value = default_value();
582 result->filename = CleanFileName();
584 result->is_default = !modified_;
585 result->has_validator_fn = validate_function() != NULL;
586 result->flag_ptr = flag_ptr();
589 void CommandLineFlag::UpdateModifiedBit() {
590 // Update the "modified" bit in case somebody bypassed the
591 // Flags API and wrote directly through the FLAGS_name variable.
592 if (!modified_ && !current_->Equal(*defvalue_)) {
597 void CommandLineFlag::CopyFrom(const CommandLineFlag& src) {
598 // Note we only copy the non-const members; others are fixed at construct time
599 if (modified_ != src.modified_) modified_ = src.modified_;
600 if (!current_->Equal(*src.current_)) current_->CopyFrom(*src.current_);
601 if (!defvalue_->Equal(*src.defvalue_)) defvalue_->CopyFrom(*src.defvalue_);
602 if (validate_fn_proto_ != src.validate_fn_proto_)
603 validate_fn_proto_ = src.validate_fn_proto_;
606 bool CommandLineFlag::Validate(const FlagValue& value) const {
608 if (validate_function() == NULL)
611 return value.Validate(name(), validate_function());
615 // --------------------------------------------------------------------
617 // A FlagRegistry singleton object holds all flag objects indexed
618 // by their names so that if you know a flag's name (as a C
619 // string), you can access or set it. If the function is named
620 // FooLocked(), you must own the registry lock before calling
621 // the function; otherwise, you should *not* hold the lock, and
622 // the function will acquire it itself if needed.
623 // --------------------------------------------------------------------
625 struct StringCmp { // Used by the FlagRegistry map class to compare char*'s
626 bool operator() (const char* s1, const char* s2) const {
627 return (strcmp(s1, s2) < 0);
637 // Not using STLDeleteElements as that resides in util and this
639 for (FlagMap::iterator p = flags_.begin(), e = flags_.end(); p != e; ++p) {
640 CommandLineFlag* flag = p->second;
645 static void DeleteGlobalRegistry() {
646 delete global_registry_;
647 global_registry_ = NULL;
650 // Store a flag in this registry. Takes ownership of the given pointer.
651 void RegisterFlag(CommandLineFlag* flag);
653 void Lock() { lock_.Lock(); }
654 void Unlock() { lock_.Unlock(); }
656 // Returns the flag object for the specified name, or NULL if not found.
657 CommandLineFlag* FindFlagLocked(const char* name);
659 // Returns the flag object whose current-value is stored at flag_ptr.
660 // That is, for whom current_->value_buffer_ == flag_ptr
661 CommandLineFlag* FindFlagViaPtrLocked(const void* flag_ptr);
663 // A fancier form of FindFlag that works correctly if name is of the
664 // form flag=value. In that case, we set key to point to flag, and
665 // modify v to point to the value (if present), and return the flag
666 // with the given name. If the flag does not exist, returns NULL
667 // and sets error_message.
668 CommandLineFlag* SplitArgumentLocked(const char* argument,
669 string* key, const char** v,
670 string* error_message);
672 // Set the value of a flag. If the flag was successfully set to
673 // value, set msg to indicate the new flag-value, and return true.
674 // Otherwise, set msg to indicate the error, leave flag unchanged,
675 // and return false. msg can be NULL.
676 bool SetFlagLocked(CommandLineFlag* flag, const char* value,
677 FlagSettingMode set_mode, string* msg);
679 static FlagRegistry* GlobalRegistry(); // returns a singleton registry
682 friend class GFLAGS_NAMESPACE::FlagSaverImpl; // reads all the flags in order to copy them
683 friend class CommandLineFlagParser; // for ValidateUnmodifiedFlags
684 friend void GFLAGS_NAMESPACE::GetAllFlags(vector<CommandLineFlagInfo>*);
686 // The map from name to flag, for FindFlagLocked().
687 typedef map<const char*, CommandLineFlag*, StringCmp> FlagMap;
688 typedef FlagMap::iterator FlagIterator;
689 typedef FlagMap::const_iterator FlagConstIterator;
692 // The map from current-value pointer to flag, fo FindFlagViaPtrLocked().
693 typedef map<const void*, CommandLineFlag*> FlagPtrMap;
694 FlagPtrMap flags_by_ptr_;
696 static FlagRegistry* global_registry_; // a singleton registry
700 static void InitGlobalRegistry();
703 FlagRegistry(const FlagRegistry&);
704 FlagRegistry& operator=(const FlagRegistry&);
707 class FlagRegistryLock {
709 explicit FlagRegistryLock(FlagRegistry* fr) : fr_(fr) { fr_->Lock(); }
710 ~FlagRegistryLock() { fr_->Unlock(); }
712 FlagRegistry *const fr_;
716 void FlagRegistry::RegisterFlag(CommandLineFlag* flag) {
718 pair<FlagIterator, bool> ins =
719 flags_.insert(pair<const char*, CommandLineFlag*>(flag->name(), flag));
720 if (ins.second == false) { // means the name was already in the map
721 if (strcmp(ins.first->second->filename(), flag->filename()) != 0) {
722 ReportError(DIE, "ERROR: flag '%s' was defined more than once "
723 "(in files '%s' and '%s').\n",
725 ins.first->second->filename(),
728 ReportError(DIE, "ERROR: something wrong with flag '%s' in file '%s'. "
729 "One possibility: file '%s' is being linked both statically "
730 "and dynamically into this executable.\n",
732 flag->filename(), flag->filename());
735 // Also add to the flags_by_ptr_ map.
736 flags_by_ptr_[flag->current_->value_buffer_] = flag;
740 CommandLineFlag* FlagRegistry::FindFlagLocked(const char* name) {
741 FlagConstIterator i = flags_.find(name);
742 if (i == flags_.end()) {
743 // If the name has dashes in it, try again after replacing with
745 if (strchr(name, '-') == NULL) return NULL;
746 string name_rep = name;
747 std::replace(name_rep.begin(), name_rep.end(), '-', '_');
748 return FindFlagLocked(name_rep.c_str());
754 CommandLineFlag* FlagRegistry::FindFlagViaPtrLocked(const void* flag_ptr) {
755 FlagPtrMap::const_iterator i = flags_by_ptr_.find(flag_ptr);
756 if (i == flags_by_ptr_.end()) {
763 CommandLineFlag* FlagRegistry::SplitArgumentLocked(const char* arg,
766 string* error_message) {
767 // Find the flag object for this option
768 const char* flag_name;
769 const char* value = strchr(arg, '=');
774 // Strip out the "=value" portion from arg
775 key->assign(arg, value-arg);
776 *v = ++value; // advance past the '='
778 flag_name = key->c_str();
780 CommandLineFlag* flag = FindFlagLocked(flag_name);
783 // If we can't find the flag-name, then we should return an error.
784 // The one exception is if 1) the flag-name is 'nox', 2) there
785 // exists a flag named 'x', and 3) 'x' is a boolean flag.
786 // In that case, we want to return flag 'x'.
787 if (!(flag_name[0] == 'n' && flag_name[1] == 'o')) {
788 // flag-name is not 'nox', so we're not in the exception case.
789 *error_message = StringPrintf("%sunknown command line flag '%s'\n",
790 kError, key->c_str());
793 flag = FindFlagLocked(flag_name+2);
795 // No flag named 'x' exists, so we're not in the exception case.
796 *error_message = StringPrintf("%sunknown command line flag '%s'\n",
797 kError, key->c_str());
800 if (flag->Type() != FlagValue::FV_BOOL) {
801 // 'x' exists but is not boolean, so we're not in the exception case.
802 *error_message = StringPrintf(
803 "%sboolean value (%s) specified for %s command line flag\n",
804 kError, key->c_str(), flag->type_name());
807 // We're in the exception case!
808 // Make up a fake value to replace the "no" we stripped out
809 key->assign(flag_name+2); // the name without the "no"
813 // Assign a value if this is a boolean flag
814 if (*v == NULL && flag->Type() == FlagValue::FV_BOOL) {
815 *v = "1"; // the --nox case was already handled, so this is the --x case
821 bool TryParseLocked(const CommandLineFlag* flag, FlagValue* flag_value,
822 const char* value, string* msg) {
823 // Use tenative_value, not flag_value, until we know value is valid.
824 FlagValue* tentative_value = flag_value->New();
825 if (!tentative_value->ParseFrom(value)) {
828 "%sillegal value '%s' specified for %s flag '%s'\n",
830 flag->type_name(), flag->name());
832 delete tentative_value;
834 } else if (!flag->Validate(*tentative_value)) {
837 "%sfailed validation of new value '%s' for flag '%s'\n",
838 kError, tentative_value->ToString().c_str(),
841 delete tentative_value;
844 flag_value->CopyFrom(*tentative_value);
846 StringAppendF(msg, "%s set to %s\n",
847 flag->name(), flag_value->ToString().c_str());
849 delete tentative_value;
854 bool FlagRegistry::SetFlagLocked(CommandLineFlag* flag,
856 FlagSettingMode set_mode,
858 flag->UpdateModifiedBit();
860 case SET_FLAGS_VALUE: {
861 // set or modify the flag's value
862 if (!TryParseLocked(flag, flag->current_, value, msg))
864 flag->modified_ = true;
867 case SET_FLAG_IF_DEFAULT: {
868 // set the flag's value, but only if it hasn't been set by someone else
869 if (!flag->modified_) {
870 if (!TryParseLocked(flag, flag->current_, value, msg))
872 flag->modified_ = true;
874 *msg = StringPrintf("%s set to %s",
875 flag->name(), flag->current_value().c_str());
879 case SET_FLAGS_DEFAULT: {
880 // modify the flag's default-value
881 if (!TryParseLocked(flag, flag->defvalue_, value, msg))
883 if (!flag->modified_) {
884 // Need to set both defvalue *and* current, in this case
885 TryParseLocked(flag, flag->current_, value, NULL);
899 // Get the singleton FlagRegistry object
900 FlagRegistry* FlagRegistry::global_registry_ = NULL;
902 FlagRegistry* FlagRegistry::GlobalRegistry() {
903 static Mutex lock(Mutex::LINKER_INITIALIZED);
904 MutexLock acquire_lock(&lock);
905 if (!global_registry_) {
906 global_registry_ = new FlagRegistry;
908 return global_registry_;
911 // --------------------------------------------------------------------
912 // CommandLineFlagParser
913 // Parsing is done in two stages. In the first, we go through
914 // argv. For every flag-like arg we can make sense of, we parse
915 // it and set the appropriate FLAGS_* variable. For every flag-
916 // like arg we can't make sense of, we store it in a vector,
917 // along with an explanation of the trouble. In stage 2, we
918 // handle the 'reporting' flags like --help and --mpm_version.
919 // (This is via a call to HandleCommandLineHelpFlags(), in
920 // gflags_reporting.cc.)
921 // An optional stage 3 prints out the error messages.
922 // This is a bit of a simplification. For instance, --flagfile
923 // is handled as soon as it's seen in stage 1, not in stage 2.
924 // --------------------------------------------------------------------
926 class CommandLineFlagParser {
928 // The argument is the flag-registry to register the parsed flags in
929 explicit CommandLineFlagParser(FlagRegistry* reg) : registry_(reg) {}
930 ~CommandLineFlagParser() {}
932 // Stage 1: Every time this is called, it reads all flags in argv.
933 // However, it ignores all flags that have been successfully set
934 // before. Typically this is only called once, so this 'reparsing'
935 // behavior isn't important. It can be useful when trying to
936 // reparse after loading a dll, though.
937 uint32 ParseNewCommandLineFlags(int* argc, char*** argv, bool remove_flags);
939 // Stage 2: print reporting info and exit, if requested.
940 // In gflags_reporting.cc:HandleCommandLineHelpFlags().
942 // Stage 3: validate all the commandline flags that have validators
943 // registered and were not set/modified by ParseNewCommandLineFlags.
944 void ValidateFlags(bool all);
945 void ValidateUnmodifiedFlags();
947 // Stage 4: report any errors and return true if any were found.
950 // Set a particular command line option. "newval" is a string
951 // describing the new value that the option has been set to. If
952 // option_name does not specify a valid option name, or value is not
953 // a valid value for option_name, newval is empty. Does recursive
954 // processing for --flagfile and --fromenv. Returns the new value
955 // if everything went ok, or empty-string if not. (Actually, the
956 // return-string could hold many flag/value pairs due to --flagfile.)
957 // NB: Must have called registry_->Lock() before calling this function.
958 string ProcessSingleOptionLocked(CommandLineFlag* flag,
960 FlagSettingMode set_mode);
962 // Set a whole batch of command line options as specified by contentdata,
963 // which is in flagfile format (and probably has been read from a flagfile).
964 // Returns the new value if everything went ok, or empty-string if
965 // not. (Actually, the return-string could hold many flag/value
966 // pairs due to --flagfile.)
967 // NB: Must have called registry_->Lock() before calling this function.
968 string ProcessOptionsFromStringLocked(const string& contentdata,
969 FlagSettingMode set_mode);
971 // These are the 'recursive' flags, defined at the top of this file.
972 // Whenever we see these flags on the commandline, we must take action.
973 // These are called by ProcessSingleOptionLocked and, similarly, return
974 // new values if everything went ok, or the empty-string if not.
975 string ProcessFlagfileLocked(const string& flagval, FlagSettingMode set_mode);
976 // diff fromenv/tryfromenv
977 string ProcessFromenvLocked(const string& flagval, FlagSettingMode set_mode,
978 bool errors_are_fatal);
981 FlagRegistry* const registry_;
982 map<string, string> error_flags_; // map from name to error message
983 // This could be a set<string>, but we reuse the map to minimize the .o size
984 map<string, string> undefined_names_; // --[flag] name was not registered
988 // Parse a list of (comma-separated) flags.
989 static void ParseFlagList(const char* value, vector<string>* flags) {
990 for (const char *p = value; p && *p; value = p) {
991 p = strchr(value, ',');
1001 ReportError(DIE, "ERROR: empty flaglist entry\n");
1002 if (value[0] == '-')
1003 ReportError(DIE, "ERROR: flag \"%*s\" begins with '-'\n", len, value);
1005 flags->push_back(string(value, len));
1009 // Snarf an entire file into a C++ string. This is just so that we
1010 // can do all the I/O in one place and not worry about it everywhere.
1011 // Plus, it's convenient to have the whole file contents at hand.
1012 // Adds a newline at the end of the file.
1013 #define PFATAL(s) do { perror(s); gflags_exitfunc(1); } while (0)
1015 static string ReadFileIntoString(const char* filename) {
1016 const int kBufSize = 8092;
1017 char buffer[kBufSize];
1020 if ((errno = SafeFOpen(&fp, filename, "r")) != 0) PFATAL(filename);
1022 while ( (n=fread(buffer, 1, kBufSize, fp)) > 0 ) {
1023 if (ferror(fp)) PFATAL(filename);
1024 s.append(buffer, n);
1030 uint32 CommandLineFlagParser::ParseNewCommandLineFlags(int* argc, char*** argv,
1031 bool remove_flags) {
1032 int first_nonopt = *argc; // for non-options moved to the end
1035 for (int i = 1; i < first_nonopt; i++) {
1036 char* arg = (*argv)[i];
1038 // Like getopt(), we permute non-option flags to be at the end.
1039 if (arg[0] != '-' || // must be a program argument
1040 (arg[0] == '-' && arg[1] == '\0')) { // "-" is an argument, not a flag
1041 memmove((*argv) + i, (*argv) + i+1, (*argc - (i+1)) * sizeof((*argv)[i]));
1042 (*argv)[*argc-1] = arg; // we go last
1043 first_nonopt--; // we've been pushed onto the stack
1044 i--; // to undo the i++ in the loop
1048 if (arg[0] == '-') arg++; // allow leading '-'
1049 if (arg[0] == '-') arg++; // or leading '--'
1051 // -- alone means what it does for GNU: stop options parsing
1057 // Find the flag object for this option
1060 string error_message;
1061 CommandLineFlag* flag = registry_->SplitArgumentLocked(arg, &key, &value,
1064 undefined_names_[key] = ""; // value isn't actually used
1065 error_flags_[key] = error_message;
1069 if (value == NULL) {
1070 // Boolean options are always assigned a value by SplitArgumentLocked()
1071 assert(flag->Type() != FlagValue::FV_BOOL);
1072 if (i+1 >= first_nonopt) {
1073 // This flag needs a value, but there is nothing available
1074 error_flags_[key] = (string(kError) + "flag '" + (*argv)[i] + "'"
1075 + " is missing its argument");
1076 if (flag->help() && flag->help()[0] > '\001') {
1077 // Be useful in case we have a non-stripped description.
1078 error_flags_[key] += string("; flag description: ") + flag->help();
1080 error_flags_[key] += "\n";
1081 break; // we treat this as an unrecoverable error
1083 value = (*argv)[++i]; // read next arg for value
1085 // Heuristic to detect the case where someone treats a string arg
1087 // --my_string_var --foo=bar
1088 // We look for a flag of string type, whose value begins with a
1089 // dash, and where the flag-name and value are separated by a
1090 // space rather than an '='.
1091 // To avoid false positives, we also require the word "true"
1092 // or "false" in the help string. Without this, a valid usage
1093 // "-lat -30.5" would trigger the warning. The common cases we
1094 // want to solve talk about true and false as values.
1096 && flag->Type() == FlagValue::FV_STRING
1097 && (strstr(flag->help(), "true")
1098 || strstr(flag->help(), "false"))) {
1099 LOG(WARNING) << "Did you really mean to set flag '"
1100 << flag->name() << "' to the value '"
1106 // TODO(csilvers): only set a flag if we hadn't set it before here
1107 ProcessSingleOptionLocked(flag, value, SET_FLAGS_VALUE);
1109 registry_->Unlock();
1111 if (remove_flags) { // Fix up argc and argv by removing command line flags
1112 (*argv)[first_nonopt-1] = (*argv)[0];
1113 (*argv) += (first_nonopt-1);
1114 (*argc) -= (first_nonopt-1);
1115 first_nonopt = 1; // because we still don't count argv[0]
1118 logging_is_probably_set_up = true; // because we've parsed --logdir, etc.
1120 return first_nonopt;
1123 string CommandLineFlagParser::ProcessFlagfileLocked(const string& flagval,
1124 FlagSettingMode set_mode) {
1125 if (flagval.empty())
1129 vector<string> filename_list;
1130 ParseFlagList(flagval.c_str(), &filename_list); // take a list of filenames
1131 for (size_t i = 0; i < filename_list.size(); ++i) {
1132 const char* file = filename_list[i].c_str();
1133 msg += ProcessOptionsFromStringLocked(ReadFileIntoString(file), set_mode);
1138 string CommandLineFlagParser::ProcessFromenvLocked(const string& flagval,
1139 FlagSettingMode set_mode,
1140 bool errors_are_fatal) {
1141 if (flagval.empty())
1145 vector<string> flaglist;
1146 ParseFlagList(flagval.c_str(), &flaglist);
1148 for (size_t i = 0; i < flaglist.size(); ++i) {
1149 const char* flagname = flaglist[i].c_str();
1150 CommandLineFlag* flag = registry_->FindFlagLocked(flagname);
1152 error_flags_[flagname] =
1153 StringPrintf("%sunknown command line flag '%s' "
1154 "(via --fromenv or --tryfromenv)\n",
1156 undefined_names_[flagname] = "";
1160 const string envname = string("FLAGS_") + string(flagname);
1162 if (!SafeGetEnv(envname.c_str(), envval)) {
1163 if (errors_are_fatal) {
1164 error_flags_[flagname] = (string(kError) + envname +
1165 " not found in environment\n");
1170 // Avoid infinite recursion.
1171 if (envval == "fromenv" || envval == "tryfromenv") {
1172 error_flags_[flagname] =
1173 StringPrintf("%sinfinite recursion on environment flag '%s'\n",
1174 kError, envval.c_str());
1178 msg += ProcessSingleOptionLocked(flag, envval.c_str(), set_mode);
1183 string CommandLineFlagParser::ProcessSingleOptionLocked(
1184 CommandLineFlag* flag, const char* value, FlagSettingMode set_mode) {
1186 if (value && !registry_->SetFlagLocked(flag, value, set_mode, &msg)) {
1187 error_flags_[flag->name()] = msg;
1191 // The recursive flags, --flagfile and --fromenv and --tryfromenv,
1192 // must be dealt with as soon as they're seen. They will emit
1193 // messages of their own.
1194 if (strcmp(flag->name(), "flagfile") == 0) {
1195 msg += ProcessFlagfileLocked(FLAGS_flagfile, set_mode);
1197 } else if (strcmp(flag->name(), "fromenv") == 0) {
1198 // last arg indicates envval-not-found is fatal (unlike in --tryfromenv)
1199 msg += ProcessFromenvLocked(FLAGS_fromenv, set_mode, true);
1201 } else if (strcmp(flag->name(), "tryfromenv") == 0) {
1202 msg += ProcessFromenvLocked(FLAGS_tryfromenv, set_mode, false);
1208 void CommandLineFlagParser::ValidateFlags(bool all) {
1209 FlagRegistryLock frl(registry_);
1210 for (FlagRegistry::FlagConstIterator i = registry_->flags_.begin();
1211 i != registry_->flags_.end(); ++i) {
1212 if ((all || !i->second->Modified()) && !i->second->ValidateCurrent()) {
1213 // only set a message if one isn't already there. (If there's
1214 // an error message, our job is done, even if it's not exactly
1216 if (error_flags_[i->second->name()].empty()) {
1217 error_flags_[i->second->name()] =
1218 string(kError) + "--" + i->second->name() +
1219 " must be set on the commandline";
1220 if (!i->second->Modified()) {
1221 error_flags_[i->second->name()] += " (default value fails validation)";
1223 error_flags_[i->second->name()] += "\n";
1229 void CommandLineFlagParser::ValidateUnmodifiedFlags() {
1230 ValidateFlags(false);
1233 bool CommandLineFlagParser::ReportErrors() {
1234 // error_flags_ indicates errors we saw while parsing.
1235 // But we ignore undefined-names if ok'ed by --undef_ok
1236 if (!FLAGS_undefok.empty()) {
1237 vector<string> flaglist;
1238 ParseFlagList(FLAGS_undefok.c_str(), &flaglist);
1239 for (size_t i = 0; i < flaglist.size(); ++i) {
1240 // We also deal with --no<flag>, in case the flagname was boolean
1241 const string no_version = string("no") + flaglist[i];
1242 if (undefined_names_.find(flaglist[i]) != undefined_names_.end()) {
1243 error_flags_[flaglist[i]] = ""; // clear the error message
1244 } else if (undefined_names_.find(no_version) != undefined_names_.end()) {
1245 error_flags_[no_version] = "";
1249 // Likewise, if they decided to allow reparsing, all undefined-names
1250 // are ok; we just silently ignore them now, and hope that a future
1251 // parse will pick them up somehow.
1252 if (allow_command_line_reparsing) {
1253 for (map<string, string>::const_iterator it = undefined_names_.begin();
1254 it != undefined_names_.end(); ++it)
1255 error_flags_[it->first] = ""; // clear the error message
1258 bool found_error = false;
1259 string error_message;
1260 for (map<string, string>::const_iterator it = error_flags_.begin();
1261 it != error_flags_.end(); ++it) {
1262 if (!it->second.empty()) {
1263 error_message.append(it->second.data(), it->second.size());
1268 ReportError(DO_NOT_DIE, "%s", error_message.c_str());
1272 string CommandLineFlagParser::ProcessOptionsFromStringLocked(
1273 const string& contentdata, FlagSettingMode set_mode) {
1275 const char* flagfile_contents = contentdata.c_str();
1276 bool flags_are_relevant = true; // set to false when filenames don't match
1277 bool in_filename_section = false;
1279 const char* line_end = flagfile_contents;
1280 // We read this file a line at a time.
1281 for (; line_end; flagfile_contents = line_end + 1) {
1282 while (*flagfile_contents && isspace(*flagfile_contents))
1283 ++flagfile_contents;
1284 // Windows uses "\r\n"
1285 line_end = strchr(flagfile_contents, '\r');
1286 if (line_end == NULL)
1287 line_end = strchr(flagfile_contents, '\n');
1289 size_t len = line_end ? line_end - flagfile_contents
1290 : strlen(flagfile_contents);
1291 string line(flagfile_contents, len);
1293 // Each line can be one of four things:
1294 // 1) A comment line -- we skip it
1295 // 2) An empty line -- we skip it
1296 // 3) A list of filenames -- starts a new filenames+flags section
1297 // 4) A --flag=value line -- apply if previous filenames match
1298 if (line.empty() || line[0] == '#') {
1299 // comment or empty line; just ignore
1301 } else if (line[0] == '-') { // flag
1302 in_filename_section = false; // instead, it was a flag-line
1303 if (!flags_are_relevant) // skip this flag; applies to someone else
1306 const char* name_and_val = line.c_str() + 1; // skip the leading -
1307 if (*name_and_val == '-')
1308 name_and_val++; // skip second - too
1311 string error_message;
1312 CommandLineFlag* flag = registry_->SplitArgumentLocked(name_and_val,
1315 // By API, errors parsing flagfile lines are silently ignored.
1317 // "WARNING: flagname '" + key + "' not found\n"
1318 } else if (value == NULL) {
1319 // "WARNING: flagname '" + key + "' missing a value\n"
1321 retval += ProcessSingleOptionLocked(flag, value, set_mode);
1324 } else { // a filename!
1325 if (!in_filename_section) { // start over: assume filenames don't match
1326 in_filename_section = true;
1327 flags_are_relevant = false;
1330 // Split the line up at spaces into glob-patterns
1331 const char* space = line.c_str(); // just has to be non-NULL
1332 for (const char* word = line.c_str(); *space; word = space+1) {
1333 if (flags_are_relevant) // we can stop as soon as we match
1335 space = strchr(word, ' ');
1337 space = word + strlen(word);
1338 const string glob(word, space - word);
1339 // We try matching both against the full argv0 and basename(argv0)
1340 if (glob == ProgramInvocationName() // small optimization
1341 || glob == ProgramInvocationShortName()
1342 #if defined(HAVE_FNMATCH_H)
1343 || fnmatch(glob.c_str(), ProgramInvocationName(), FNM_PATHNAME) == 0
1344 || fnmatch(glob.c_str(), ProgramInvocationShortName(), FNM_PATHNAME) == 0
1345 #elif defined(HAVE_SHLWAPI_H)
1346 || PathMatchSpec(glob.c_str(), ProgramInvocationName())
1347 || PathMatchSpec(glob.c_str(), ProgramInvocationShortName())
1350 flags_are_relevant = true;
1358 // --------------------------------------------------------------------
1360 // AddFlagValidator()
1361 // These are helper functions for routines like BoolFromEnv() and
1362 // RegisterFlagValidator, defined below. They're defined here so
1363 // they can live in the unnamed namespace (which makes friendship
1364 // declarations for these classes possible).
1365 // --------------------------------------------------------------------
1367 template<typename T>
1368 T GetFromEnv(const char *varname, T dflt) {
1370 if (SafeGetEnv(varname, valstr)) {
1371 FlagValue ifv(new T, true);
1372 if (!ifv.ParseFrom(valstr.c_str())) {
1373 ReportError(DIE, "ERROR: error parsing env variable '%s' with value '%s'\n",
1374 varname, valstr.c_str());
1376 return OTHER_VALUE_AS(ifv, T);
1380 bool AddFlagValidator(const void* flag_ptr, ValidateFnProto validate_fn_proto) {
1381 // We want a lock around this routine, in case two threads try to
1382 // add a validator (hopefully the same one!) at once. We could use
1383 // our own thread, but we need to loook at the registry anyway, so
1384 // we just steal that one.
1385 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1386 FlagRegistryLock frl(registry);
1387 // First, find the flag whose current-flag storage is 'flag'.
1388 // This is the CommandLineFlag whose current_->value_buffer_ == flag
1389 CommandLineFlag* flag = registry->FindFlagViaPtrLocked(flag_ptr);
1391 LOG(WARNING) << "Ignoring RegisterValidateFunction() for flag pointer "
1392 << flag_ptr << ": no flag found at that address";
1394 } else if (validate_fn_proto == flag->validate_function()) {
1395 return true; // ok to register the same function over and over again
1396 } else if (validate_fn_proto != NULL && flag->validate_function() != NULL) {
1397 LOG(WARNING) << "Ignoring RegisterValidateFunction() for flag '"
1398 << flag->name() << "': validate-fn already registered";
1401 flag->validate_fn_proto_ = validate_fn_proto;
1406 } // end unnamed namespaces
1409 // Now define the functions that are exported via the .h file
1411 // --------------------------------------------------------------------
1413 // This class exists merely to have a global constructor (the
1414 // kind that runs before main(), that goes an initializes each
1415 // flag that's been declared. Note that it's very important we
1416 // don't have a destructor that deletes flag_, because that would
1417 // cause us to delete current_storage/defvalue_storage as well,
1418 // which can cause a crash if anything tries to access the flag
1419 // values in a global destructor.
1420 // --------------------------------------------------------------------
1423 void RegisterCommandLineFlag(const char* name,
1425 const char* filename,
1427 FlagValue* defvalue) {
1430 // Importantly, flag_ will never be deleted, so storage is always good.
1431 CommandLineFlag* flag =
1432 new CommandLineFlag(name, help, filename, current, defvalue);
1433 FlagRegistry::GlobalRegistry()->RegisterFlag(flag); // default registry
1437 template <typename FlagType>
1438 FlagRegisterer::FlagRegisterer(const char* name,
1440 const char* filename,
1441 FlagType* current_storage,
1442 FlagType* defvalue_storage) {
1443 FlagValue* const current = new FlagValue(current_storage, false);
1444 FlagValue* const defvalue = new FlagValue(defvalue_storage, false);
1445 RegisterCommandLineFlag(name, help, filename, current, defvalue);
1448 // Force compiler to generate code for the given template specialization.
1449 #define INSTANTIATE_FLAG_REGISTERER_CTOR(type) \
1450 template GFLAGS_DLL_DECL FlagRegisterer::FlagRegisterer( \
1451 const char* name, const char* help, const char* filename, \
1452 type* current_storage, type* defvalue_storage)
1454 // Do this for all supported flag types.
1455 INSTANTIATE_FLAG_REGISTERER_CTOR(bool);
1456 INSTANTIATE_FLAG_REGISTERER_CTOR(int32);
1457 INSTANTIATE_FLAG_REGISTERER_CTOR(uint32);
1458 INSTANTIATE_FLAG_REGISTERER_CTOR(int64);
1459 INSTANTIATE_FLAG_REGISTERER_CTOR(uint64);
1460 INSTANTIATE_FLAG_REGISTERER_CTOR(double);
1461 INSTANTIATE_FLAG_REGISTERER_CTOR(std::string);
1463 #undef INSTANTIATE_FLAG_REGISTERER_CTOR
1465 // --------------------------------------------------------------------
1467 // The main way the FlagRegistry class exposes its data. This
1468 // returns, as strings, all the info about all the flags in
1469 // the main registry, sorted first by filename they are defined
1470 // in, and then by flagname.
1471 // --------------------------------------------------------------------
1473 struct FilenameFlagnameCmp {
1474 bool operator()(const CommandLineFlagInfo& a,
1475 const CommandLineFlagInfo& b) const {
1476 int cmp = strcmp(a.filename.c_str(), b.filename.c_str());
1478 cmp = strcmp(a.name.c_str(), b.name.c_str()); // secondary sort key
1483 void GetAllFlags(vector<CommandLineFlagInfo>* OUTPUT) {
1484 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1486 for (FlagRegistry::FlagConstIterator i = registry->flags_.begin();
1487 i != registry->flags_.end(); ++i) {
1488 CommandLineFlagInfo fi;
1489 i->second->FillCommandLineFlagInfo(&fi);
1490 OUTPUT->push_back(fi);
1493 // Now sort the flags, first by filename they occur in, then alphabetically
1494 sort(OUTPUT->begin(), OUTPUT->end(), FilenameFlagnameCmp());
1497 // --------------------------------------------------------------------
1502 // ProgramInvocationName()
1503 // ProgramInvocationShortName()
1504 // SetUsageMessage()
1506 // Functions to set and get argv. Typically the setter is called
1507 // by ParseCommandLineFlags. Also can get the ProgramUsage string,
1508 // set by SetUsageMessage.
1509 // --------------------------------------------------------------------
1511 // These values are not protected by a Mutex because they are normally
1512 // set only once during program startup.
1513 static string argv0("UNKNOWN"); // just the program name
1514 static string cmdline; // the entire command-line
1515 static string program_usage;
1516 static vector<string> argvs;
1517 static uint32 argv_sum = 0;
1519 void SetArgv(int argc, const char** argv) {
1520 static bool called_set_argv = false;
1521 if (called_set_argv) return;
1522 called_set_argv = true;
1524 assert(argc > 0); // every program has at least a name
1528 for (int i = 0; i < argc; i++) {
1529 if (i != 0) cmdline += " ";
1531 argvs.push_back(argv[i]);
1534 // Compute a simple sum of all the chars in argv
1536 for (string::const_iterator c = cmdline.begin(); c != cmdline.end(); ++c) {
1541 const vector<string>& GetArgvs() { return argvs; }
1542 const char* GetArgv() { return cmdline.c_str(); }
1543 const char* GetArgv0() { return argv0.c_str(); }
1544 uint32 GetArgvSum() { return argv_sum; }
1545 const char* ProgramInvocationName() { // like the GNU libc fn
1548 const char* ProgramInvocationShortName() { // like the GNU libc fn
1549 size_t pos = argv0.rfind('/');
1551 if (pos == string::npos) pos = argv0.rfind('\\');
1553 return (pos == string::npos ? argv0.c_str() : (argv0.c_str() + pos + 1));
1556 void SetUsageMessage(const string& usage) {
1557 program_usage = usage;
1560 const char* ProgramUsage() {
1561 if (program_usage.empty()) {
1562 return "Warning: SetUsageMessage() never called";
1564 return program_usage.c_str();
1567 // --------------------------------------------------------------------
1568 // SetVersionString()
1570 // --------------------------------------------------------------------
1572 static string version_string;
1574 void SetVersionString(const string& version) {
1575 version_string = version;
1578 const char* VersionString() {
1579 return version_string.c_str();
1583 // --------------------------------------------------------------------
1584 // GetCommandLineOption()
1585 // GetCommandLineFlagInfo()
1586 // GetCommandLineFlagInfoOrDie()
1587 // SetCommandLineOption()
1588 // SetCommandLineOptionWithMode()
1589 // The programmatic way to set a flag's value, using a string
1590 // for its name rather than the variable itself (that is,
1591 // SetCommandLineOption("foo", x) rather than FLAGS_foo = x).
1592 // There's also a bit more flexibility here due to the various
1593 // set-modes, but typically these are used when you only have
1594 // that flag's name as a string, perhaps at runtime.
1595 // All of these work on the default, global registry.
1596 // For GetCommandLineOption, return false if no such flag
1597 // is known, true otherwise. We clear "value" if a suitable
1599 // --------------------------------------------------------------------
1602 bool GetCommandLineOption(const char* name, string* value) {
1607 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1608 FlagRegistryLock frl(registry);
1609 CommandLineFlag* flag = registry->FindFlagLocked(name);
1613 *value = flag->current_value();
1618 bool GetCommandLineFlagInfo(const char* name, CommandLineFlagInfo* OUTPUT) {
1619 if (NULL == name) return false;
1620 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1621 FlagRegistryLock frl(registry);
1622 CommandLineFlag* flag = registry->FindFlagLocked(name);
1627 flag->FillCommandLineFlagInfo(OUTPUT);
1632 CommandLineFlagInfo GetCommandLineFlagInfoOrDie(const char* name) {
1633 CommandLineFlagInfo info;
1634 if (!GetCommandLineFlagInfo(name, &info)) {
1635 fprintf(stderr, "FATAL ERROR: flag name '%s' doesn't exist\n", name);
1636 gflags_exitfunc(1); // almost certainly gflags_exitfunc()
1641 string SetCommandLineOptionWithMode(const char* name, const char* value,
1642 FlagSettingMode set_mode) {
1644 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1645 FlagRegistryLock frl(registry);
1646 CommandLineFlag* flag = registry->FindFlagLocked(name);
1648 CommandLineFlagParser parser(registry);
1649 result = parser.ProcessSingleOptionLocked(flag, value, set_mode);
1650 if (!result.empty()) { // in the error case, we've already logged
1651 // Could consider logging this change
1654 // The API of this function is that we return empty string on error
1658 string SetCommandLineOption(const char* name, const char* value) {
1659 return SetCommandLineOptionWithMode(name, value, SET_FLAGS_VALUE);
1662 // --------------------------------------------------------------------
1665 // This class stores the states of all flags at construct time,
1666 // and restores all flags to that state at destruct time.
1667 // Its major implementation challenge is that it never modifies
1668 // pointers in the 'main' registry, so global FLAG_* vars always
1669 // point to the right place.
1670 // --------------------------------------------------------------------
1672 class FlagSaverImpl {
1674 // Constructs an empty FlagSaverImpl object.
1675 explicit FlagSaverImpl(FlagRegistry* main_registry)
1676 : main_registry_(main_registry) { }
1678 // reclaim memory from each of our CommandLineFlags
1679 vector<CommandLineFlag*>::const_iterator it;
1680 for (it = backup_registry_.begin(); it != backup_registry_.end(); ++it)
1684 // Saves the flag states from the flag registry into this object.
1685 // It's an error to call this more than once.
1686 // Must be called when the registry mutex is not held.
1687 void SaveFromRegistry() {
1688 FlagRegistryLock frl(main_registry_);
1689 assert(backup_registry_.empty()); // call only once!
1690 for (FlagRegistry::FlagConstIterator it = main_registry_->flags_.begin();
1691 it != main_registry_->flags_.end();
1693 const CommandLineFlag* main = it->second;
1694 // Sets up all the const variables in backup correctly
1695 CommandLineFlag* backup = new CommandLineFlag(
1696 main->name(), main->help(), main->filename(),
1697 main->current_->New(), main->defvalue_->New());
1698 // Sets up all the non-const variables in backup correctly
1699 backup->CopyFrom(*main);
1700 backup_registry_.push_back(backup); // add it to a convenient list
1704 // Restores the saved flag states into the flag registry. We
1705 // assume no flags were added or deleted from the registry since
1706 // the SaveFromRegistry; if they were, that's trouble! Must be
1707 // called when the registry mutex is not held.
1708 void RestoreToRegistry() {
1709 FlagRegistryLock frl(main_registry_);
1710 vector<CommandLineFlag*>::const_iterator it;
1711 for (it = backup_registry_.begin(); it != backup_registry_.end(); ++it) {
1712 CommandLineFlag* main = main_registry_->FindFlagLocked((*it)->name());
1713 if (main != NULL) { // if NULL, flag got deleted from registry(!)
1714 main->CopyFrom(**it);
1720 FlagRegistry* const main_registry_;
1721 vector<CommandLineFlag*> backup_registry_;
1723 FlagSaverImpl(const FlagSaverImpl&); // no copying!
1724 void operator=(const FlagSaverImpl&);
1727 FlagSaver::FlagSaver()
1728 : impl_(new FlagSaverImpl(FlagRegistry::GlobalRegistry())) {
1729 impl_->SaveFromRegistry();
1732 FlagSaver::~FlagSaver() {
1733 impl_->RestoreToRegistry();
1738 // --------------------------------------------------------------------
1739 // CommandlineFlagsIntoString()
1740 // ReadFlagsFromString()
1741 // AppendFlagsIntoFile()
1742 // ReadFromFlagsFile()
1743 // These are mostly-deprecated routines that stick the
1744 // commandline flags into a file/string and read them back
1745 // out again. I can see a use for CommandlineFlagsIntoString,
1746 // for creating a flagfile, but the rest don't seem that useful
1747 // -- some, I think, are a poor-man's attempt at FlagSaver --
1748 // and are included only until we can delete them from callers.
1749 // Note they don't save --flagfile flags (though they do save
1750 // the result of having called the flagfile, of course).
1751 // --------------------------------------------------------------------
1753 static string TheseCommandlineFlagsIntoString(
1754 const vector<CommandLineFlagInfo>& flags) {
1755 vector<CommandLineFlagInfo>::const_iterator i;
1757 size_t retval_space = 0;
1758 for (i = flags.begin(); i != flags.end(); ++i) {
1759 // An (over)estimate of how much space it will take to print this flag
1760 retval_space += i->name.length() + i->current_value.length() + 5;
1764 retval.reserve(retval_space);
1765 for (i = flags.begin(); i != flags.end(); ++i) {
1769 retval += i->current_value;
1775 string CommandlineFlagsIntoString() {
1776 vector<CommandLineFlagInfo> sorted_flags;
1777 GetAllFlags(&sorted_flags);
1778 return TheseCommandlineFlagsIntoString(sorted_flags);
1781 bool ReadFlagsFromString(const string& flagfilecontents,
1782 const char* /*prog_name*/, // TODO(csilvers): nix this
1783 bool errors_are_fatal) {
1784 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1785 FlagSaverImpl saved_states(registry);
1786 saved_states.SaveFromRegistry();
1788 CommandLineFlagParser parser(registry);
1790 parser.ProcessOptionsFromStringLocked(flagfilecontents, SET_FLAGS_VALUE);
1792 // Should we handle --help and such when reading flags from a string? Sure.
1793 HandleCommandLineHelpFlags();
1794 if (parser.ReportErrors()) {
1795 // Error. Restore all global flags to their previous values.
1796 if (errors_are_fatal)
1798 saved_states.RestoreToRegistry();
1804 // TODO(csilvers): nix prog_name in favor of ProgramInvocationShortName()
1805 bool AppendFlagsIntoFile(const string& filename, const char *prog_name) {
1807 if (SafeFOpen(&fp, filename.c_str(), "a") != 0) {
1812 fprintf(fp, "%s\n", prog_name);
1814 vector<CommandLineFlagInfo> flags;
1815 GetAllFlags(&flags);
1816 // But we don't want --flagfile, which leads to weird recursion issues
1817 vector<CommandLineFlagInfo>::iterator i;
1818 for (i = flags.begin(); i != flags.end(); ++i) {
1819 if (strcmp(i->name.c_str(), "flagfile") == 0) {
1824 fprintf(fp, "%s", TheseCommandlineFlagsIntoString(flags).c_str());
1830 bool ReadFromFlagsFile(const string& filename, const char* prog_name,
1831 bool errors_are_fatal) {
1832 return ReadFlagsFromString(ReadFileIntoString(filename.c_str()),
1833 prog_name, errors_are_fatal);
1837 // --------------------------------------------------------------------
1845 // Reads the value from the environment and returns it.
1846 // We use an FlagValue to make the parsing easy.
1848 // DEFINE_bool(myflag, BoolFromEnv("MYFLAG_DEFAULT", false), "whatever");
1849 // --------------------------------------------------------------------
1851 bool BoolFromEnv(const char *v, bool dflt) {
1852 return GetFromEnv(v, dflt);
1854 int32 Int32FromEnv(const char *v, int32 dflt) {
1855 return GetFromEnv(v, dflt);
1857 uint32 Uint32FromEnv(const char *v, uint32 dflt) {
1858 return GetFromEnv(v, dflt);
1860 int64 Int64FromEnv(const char *v, int64 dflt) {
1861 return GetFromEnv(v, dflt);
1863 uint64 Uint64FromEnv(const char *v, uint64 dflt) {
1864 return GetFromEnv(v, dflt);
1866 double DoubleFromEnv(const char *v, double dflt) {
1867 return GetFromEnv(v, dflt);
1871 # pragma warning(push)
1872 # pragma warning(disable: 4996) // ignore getenv security warning
1874 const char *StringFromEnv(const char *varname, const char *dflt) {
1875 const char* const val = getenv(varname);
1876 return val ? val : dflt;
1879 # pragma warning(pop)
1883 // --------------------------------------------------------------------
1884 // RegisterFlagValidator()
1885 // RegisterFlagValidator() is the function that clients use to
1886 // 'decorate' a flag with a validation function. Once this is
1887 // done, every time the flag is set (including when the flag
1888 // is parsed from argv), the validator-function is called.
1889 // These functions return true if the validator was added
1890 // successfully, or false if not: the flag already has a validator,
1891 // (only one allowed per flag), the 1st arg isn't a flag, etc.
1892 // This function is not thread-safe.
1893 // --------------------------------------------------------------------
1895 bool RegisterFlagValidator(const bool* flag,
1896 bool (*validate_fn)(const char*, bool)) {
1897 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1899 bool RegisterFlagValidator(const int32* flag,
1900 bool (*validate_fn)(const char*, int32)) {
1901 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1903 bool RegisterFlagValidator(const uint32* flag,
1904 bool (*validate_fn)(const char*, uint32)) {
1905 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1907 bool RegisterFlagValidator(const int64* flag,
1908 bool (*validate_fn)(const char*, int64)) {
1909 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1911 bool RegisterFlagValidator(const uint64* flag,
1912 bool (*validate_fn)(const char*, uint64)) {
1913 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1915 bool RegisterFlagValidator(const double* flag,
1916 bool (*validate_fn)(const char*, double)) {
1917 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1919 bool RegisterFlagValidator(const string* flag,
1920 bool (*validate_fn)(const char*, const string&)) {
1921 return AddFlagValidator(flag, reinterpret_cast<ValidateFnProto>(validate_fn));
1925 // --------------------------------------------------------------------
1926 // ParseCommandLineFlags()
1927 // ParseCommandLineNonHelpFlags()
1928 // HandleCommandLineHelpFlags()
1929 // This is the main function called from main(), to actually
1930 // parse the commandline. It modifies argc and argv as described
1931 // at the top of gflags.h. You can also divide this
1932 // function into two parts, if you want to do work between
1933 // the parsing of the flags and the printing of any help output.
1934 // --------------------------------------------------------------------
1936 static uint32 ParseCommandLineFlagsInternal(int* argc, char*** argv,
1937 bool remove_flags, bool do_report) {
1938 SetArgv(*argc, const_cast<const char**>(*argv)); // save it for later
1940 FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
1941 CommandLineFlagParser parser(registry);
1943 // When we parse the commandline flags, we'll handle --flagfile,
1944 // --tryfromenv, etc. as we see them (since flag-evaluation order
1945 // may be important). But sometimes apps set FLAGS_tryfromenv/etc.
1946 // manually before calling ParseCommandLineFlags. We want to evaluate
1947 // those too, as if they were the first flags on the commandline.
1949 parser.ProcessFlagfileLocked(FLAGS_flagfile, SET_FLAGS_VALUE);
1950 // Last arg here indicates whether flag-not-found is a fatal error or not
1951 parser.ProcessFromenvLocked(FLAGS_fromenv, SET_FLAGS_VALUE, true);
1952 parser.ProcessFromenvLocked(FLAGS_tryfromenv, SET_FLAGS_VALUE, false);
1955 // Now get the flags specified on the commandline
1956 const int r = parser.ParseNewCommandLineFlags(argc, argv, remove_flags);
1959 HandleCommandLineHelpFlags(); // may cause us to exit on --help, etc.
1961 // See if any of the unset flags fail their validation checks
1962 parser.ValidateUnmodifiedFlags();
1964 if (parser.ReportErrors()) // may cause us to exit on illegal flags
1969 uint32 ParseCommandLineFlags(int* argc, char*** argv, bool remove_flags) {
1970 return ParseCommandLineFlagsInternal(argc, argv, remove_flags, true);
1973 uint32 ParseCommandLineNonHelpFlags(int* argc, char*** argv,
1974 bool remove_flags) {
1975 return ParseCommandLineFlagsInternal(argc, argv, remove_flags, false);
1978 // --------------------------------------------------------------------
1979 // AllowCommandLineReparsing()
1980 // ReparseCommandLineNonHelpFlags()
1981 // This is most useful for shared libraries. The idea is if
1982 // a flag is defined in a shared library that is dlopen'ed
1983 // sometime after main(), you can ParseCommandLineFlags before
1984 // the dlopen, then ReparseCommandLineNonHelpFlags() after the
1985 // dlopen, to get the new flags. But you have to explicitly
1986 // Allow() it; otherwise, you get the normal default behavior
1987 // of unrecognized flags calling a fatal error.
1988 // TODO(csilvers): this isn't used. Just delete it?
1989 // --------------------------------------------------------------------
1991 void AllowCommandLineReparsing() {
1992 allow_command_line_reparsing = true;
1995 void ReparseCommandLineNonHelpFlags() {
1996 // We make a copy of argc and argv to pass in
1997 const vector<string>& argvs = GetArgvs();
1998 int tmp_argc = static_cast<int>(argvs.size());
1999 char** tmp_argv = new char* [tmp_argc + 1];
2000 for (int i = 0; i < tmp_argc; ++i)
2001 tmp_argv[i] = strdup(argvs[i].c_str()); // TODO(csilvers): don't dup
2003 ParseCommandLineNonHelpFlags(&tmp_argc, &tmp_argv, false);
2005 for (int i = 0; i < tmp_argc; ++i)
2010 void ShutDownCommandLineFlags() {
2011 FlagRegistry::DeleteGlobalRegistry();
2015 } // namespace GFLAGS_NAMESPACE