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Issue 1413723002: Add gflags dependency (Closed) Base URL: https://chromium.googlesource.com/libyuv/libyuv@master
Patch Set: Fix .gitignore Created 5 years, 2 months ago
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1 // Copyright (c) 2006, Google Inc.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
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
13 // distribution.
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.
17 //
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.
29
30 // ---
31 // Author: Ray Sidney
32 // Revamped and reorganized by Craig Silverstein
33 //
34 // This is the file that should be included by any file which declares
35 // or defines a command line flag or wants to parse command line flags
36 // or print a program usage message (which will include information about
37 // flags). Executive summary, in the form of an example foo.cc file:
38 //
39 // #include "foo.h" // foo.h has a line "DECLARE_int32(start);"
40 // #include "validators.h" // hypothetical file defining ValidateIsFile()
41 //
42 // DEFINE_int32(end, 1000, "The last record to read");
43 //
44 // DEFINE_string(filename, "my_file.txt", "The file to read");
45 // // Crash if the specified file does not exist.
46 // static bool dummy = RegisterFlagValidator(&FLAGS_filename,
47 // &ValidateIsFile);
48 //
49 // DECLARE_bool(verbose); // some other file has a DEFINE_bool(verbose, ...)
50 //
51 // void MyFunc() {
52 // if (FLAGS_verbose) printf("Records %d-%d\n", FLAGS_start, FLAGS_end);
53 // }
54 //
55 // Then, at the command-line:
56 // ./foo --noverbose --start=5 --end=100
57 //
58 // For more details, see
59 // doc/gflags.html
60 //
61 // --- A note about thread-safety:
62 //
63 // We describe many functions in this routine as being thread-hostile,
64 // thread-compatible, or thread-safe. Here are the meanings we use:
65 //
66 // thread-safe: it is safe for multiple threads to call this routine
67 // (or, when referring to a class, methods of this class)
68 // concurrently.
69 // thread-hostile: it is not safe for multiple threads to call this
70 // routine (or methods of this class) concurrently. In gflags,
71 // most thread-hostile routines are intended to be called early in,
72 // or even before, main() -- that is, before threads are spawned.
73 // thread-compatible: it is safe for multiple threads to read from
74 // this variable (when applied to variables), or to call const
75 // methods of this class (when applied to classes), as long as no
76 // other thread is writing to the variable or calling non-const
77 // methods of this class.
78
79 #ifndef GOOGLE_GFLAGS_H_
80 #define GOOGLE_GFLAGS_H_
81
82 #include <string>
83 #include <vector>
84
85 // We care a lot about number of bits things take up. Unfortunately,
86 // systems define their bit-specific ints in a lot of different ways.
87 // We use our own way, and have a typedef to get there.
88 // Note: these commands below may look like "#if 1" or "#if 0", but
89 // that's because they were constructed that way at ./configure time.
90 // Look at gflags.h.in to see how they're calculated (based on your config).
91 #if 0
92 #include <stdint.h> // the normal place uint16_t is defined
93 #endif
94 #if 1
95 #include <sys/types.h> // the normal place u_int16_t is defined
96 #endif
97 #if 0
98 #include <inttypes.h> // a third place for uint16_t or u_int16_t
99 #endif
100
101 // Annoying stuff for windows -- makes sure clients can import these functions
102 #if defined(_WIN32)
103 # ifndef GFLAGS_DLL_DECL
104 # define GFLAGS_DLL_DECL __declspec(dllimport)
105 # endif
106 # ifndef GFLAGS_DLL_DECLARE_FLAG
107 # define GFLAGS_DLL_DECLARE_FLAG __declspec(dllimport)
108 # endif
109 # ifndef GFLAGS_DLL_DEFINE_FLAG
110 # define GFLAGS_DLL_DEFINE_FLAG __declspec(dllexport)
111 # endif
112 #else
113 # ifndef GFLAGS_DLL_DECL
114 # define GFLAGS_DLL_DECL
115 # endif
116 # ifndef GFLAGS_DLL_DECLARE_FLAG
117 # define GFLAGS_DLL_DECLARE_FLAG
118 # endif
119 # ifndef GFLAGS_DLL_DEFINE_FLAG
120 # define GFLAGS_DLL_DEFINE_FLAG
121 # endif
122 #endif
123
124 namespace google {
125
126 #if 0 // the C99 format
127 typedef int32_t int32;
128 typedef uint32_t uint32;
129 typedef int64_t int64;
130 typedef uint64_t uint64;
131 #elif 0 // the BSD format
132 typedef int32_t int32;
133 typedef u_int32_t uint32;
134 typedef int64_t int64;
135 typedef u_int64_t uint64;
136 #elif 1 // the windows (vc7) format
137 typedef __int32 int32;
138 typedef unsigned __int32 uint32;
139 typedef __int64 int64;
140 typedef unsigned __int64 uint64;
141 #else
142 #error Do not know how to define a 32-bit integer quantity on your system
143 #endif
144
145 // TODO(kjellander): update generated .h's for new gflags.
146 // https://code.google.com/p/webrtc/issues/detail?id=2251
147 extern const char* VersionString();
148 extern void SetVersionString(const std::string& version);
149
150 // --------------------------------------------------------------------
151 // To actually define a flag in a file, use DEFINE_bool,
152 // DEFINE_string, etc. at the bottom of this file. You may also find
153 // it useful to register a validator with the flag. This ensures that
154 // when the flag is parsed from the commandline, or is later set via
155 // SetCommandLineOption, we call the validation function. It is _not_
156 // called when you assign the value to the flag directly using the = operator.
157 //
158 // The validation function should return true if the flag value is valid, and
159 // false otherwise. If the function returns false for the new setting of the
160 // flag, the flag will retain its current value. If it returns false for the
161 // default value, ParseCommandLineFlags() will die.
162 //
163 // This function is safe to call at global construct time (as in the
164 // example below).
165 //
166 // Example use:
167 // static bool ValidatePort(const char* flagname, int32 value) {
168 // if (value > 0 && value < 32768) // value is ok
169 // return true;
170 // printf("Invalid value for --%s: %d\n", flagname, (int)value);
171 // return false;
172 // }
173 // DEFINE_int32(port, 0, "What port to listen on");
174 // static bool dummy = RegisterFlagValidator(&FLAGS_port, &ValidatePort);
175
176 // Returns true if successfully registered, false if not (because the
177 // first argument doesn't point to a command-line flag, or because a
178 // validator is already registered for this flag).
179 GFLAGS_DLL_DECL bool RegisterFlagValidator(const bool* flag,
180 bool (*validate_fn)(const char*, bool));
181 GFLAGS_DLL_DECL bool RegisterFlagValidator(const int32* flag,
182 bool (*validate_fn)(const char*, int32));
183 GFLAGS_DLL_DECL bool RegisterFlagValidator(const int64* flag,
184 bool (*validate_fn)(const char*, int64));
185 GFLAGS_DLL_DECL bool RegisterFlagValidator(const uint64* flag,
186 bool (*validate_fn)(const char*, uint64));
187 GFLAGS_DLL_DECL bool RegisterFlagValidator(const double* flag,
188 bool (*validate_fn)(const char*, double));
189 GFLAGS_DLL_DECL bool RegisterFlagValidator(const std::string* flag,
190 bool (*validate_fn)(const char*, const std::string&)) ;
191
192
193 // --------------------------------------------------------------------
194 // These methods are the best way to get access to info about the
195 // list of commandline flags. Note that these routines are pretty slow.
196 // GetAllFlags: mostly-complete info about the list, sorted by file.
197 // ShowUsageWithFlags: pretty-prints the list to stdout (what --help does)
198 // ShowUsageWithFlagsRestrict: limit to filenames with restrict as a substr
199 //
200 // In addition to accessing flags, you can also access argv[0] (the program
201 // name) and argv (the entire commandline), which we sock away a copy of.
202 // These variables are static, so you should only set them once.
203
204 struct GFLAGS_DLL_DECL CommandLineFlagInfo {
205 std::string name; // the name of the flag
206 std::string type; // the type of the flag: int32, etc
207 std::string description; // the "help text" associated with the flag
208 std::string current_value; // the current value, as a string
209 std::string default_value; // the default value, as a string
210 std::string filename; // 'cleaned' version of filename holding the flag
211 bool has_validator_fn; // true if RegisterFlagValidator called on flag
212 bool is_default; // true if the flag has the default value and
213 // has not been set explicitly from the cmdline
214 // or via SetCommandLineOption
215 const void* flag_ptr;
216 };
217
218 // Using this inside of a validator is a recipe for a deadlock.
219 // TODO(wojtekm) Fix locking when validators are running, to make it safe to
220 // call validators during ParseAllFlags.
221 // Also make sure then to uncomment the corresponding unit test in
222 // commandlineflags_unittest.sh
223 extern GFLAGS_DLL_DECL void GetAllFlags(std::vector<CommandLineFlagInfo>* OUTPUT );
224 // These two are actually defined in commandlineflags_reporting.cc.
225 extern GFLAGS_DLL_DECL void ShowUsageWithFlags(const char *argv0); // what --he lp does
226 extern GFLAGS_DLL_DECL void ShowUsageWithFlagsRestrict(const char *argv0, const char *restrict);
227
228 // Create a descriptive string for a flag.
229 // Goes to some trouble to make pretty line breaks.
230 extern GFLAGS_DLL_DECL std::string DescribeOneFlag(const CommandLineFlagInfo& fl ag);
231
232 // Thread-hostile; meant to be called before any threads are spawned.
233 extern GFLAGS_DLL_DECL void SetArgv(int argc, const char** argv);
234 // The following functions are thread-safe as long as SetArgv() is
235 // only called before any threads start.
236 extern GFLAGS_DLL_DECL const std::vector<std::string>& GetArgvs(); // all of ar gv as a vector
237 extern GFLAGS_DLL_DECL const char* GetArgv(); // all of argv as a string
238 extern GFLAGS_DLL_DECL const char* GetArgv0(); // only argv0
239 extern GFLAGS_DLL_DECL uint32 GetArgvSum(); // simple checksum o f argv
240 extern GFLAGS_DLL_DECL const char* ProgramInvocationName(); // argv0, or "UNKNOW N" if not set
241 extern GFLAGS_DLL_DECL const char* ProgramInvocationShortName(); // basename(a rgv0)
242 // ProgramUsage() is thread-safe as long as SetUsageMessage() is only
243 // called before any threads start.
244 extern GFLAGS_DLL_DECL const char* ProgramUsage(); // string set by Set UsageMessage()
245
246
247 // --------------------------------------------------------------------
248 // Normally you access commandline flags by just saying "if (FLAGS_foo)"
249 // or whatever, and set them by calling "FLAGS_foo = bar" (or, more
250 // commonly, via the DEFINE_foo macro). But if you need a bit more
251 // control, we have programmatic ways to get/set the flags as well.
252 // These programmatic ways to access flags are thread-safe, but direct
253 // access is only thread-compatible.
254
255 // Return true iff the flagname was found.
256 // OUTPUT is set to the flag's value, or unchanged if we return false.
257 extern GFLAGS_DLL_DECL bool GetCommandLineOption(const char* name, std::string* OUTPUT);
258
259 // Return true iff the flagname was found. OUTPUT is set to the flag's
260 // CommandLineFlagInfo or unchanged if we return false.
261 extern GFLAGS_DLL_DECL bool GetCommandLineFlagInfo(const char* name,
262 CommandLineFlagInfo* OUTPUT);
263
264 // Return the CommandLineFlagInfo of the flagname. exit() if name not found.
265 // Example usage, to check if a flag's value is currently the default value:
266 // if (GetCommandLineFlagInfoOrDie("foo").is_default) ...
267 extern GFLAGS_DLL_DECL CommandLineFlagInfo GetCommandLineFlagInfoOrDie(const cha r* name);
268
269 enum GFLAGS_DLL_DECL FlagSettingMode {
270 // update the flag's value (can call this multiple times).
271 SET_FLAGS_VALUE,
272 // update the flag's value, but *only if* it has not yet been updated
273 // with SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef".
274 SET_FLAG_IF_DEFAULT,
275 // set the flag's default value to this. If the flag has not yet updated
276 // yet (via SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef")
277 // change the flag's current value to the new default value as well.
278 SET_FLAGS_DEFAULT
279 };
280
281 // Set a particular flag ("command line option"). Returns a string
282 // describing the new value that the option has been set to. The
283 // return value API is not well-specified, so basically just depend on
284 // it to be empty if the setting failed for some reason -- the name is
285 // not a valid flag name, or the value is not a valid value -- and
286 // non-empty else.
287
288 // SetCommandLineOption uses set_mode == SET_FLAGS_VALUE (the common case)
289 extern GFLAGS_DLL_DECL std::string SetCommandLineOption(const char* name, const char* value);
290 extern GFLAGS_DLL_DECL std::string SetCommandLineOptionWithMode(const char* name , const char* value,
291 FlagSettingMode set_mode);
292
293
294 // --------------------------------------------------------------------
295 // Saves the states (value, default value, whether the user has set
296 // the flag, registered validators, etc) of all flags, and restores
297 // them when the FlagSaver is destroyed. This is very useful in
298 // tests, say, when you want to let your tests change the flags, but
299 // make sure that they get reverted to the original states when your
300 // test is complete.
301 //
302 // Example usage:
303 // void TestFoo() {
304 // FlagSaver s1;
305 // FLAG_foo = false;
306 // FLAG_bar = "some value";
307 //
308 // // test happens here. You can return at any time
309 // // without worrying about restoring the FLAG values.
310 // }
311 //
312 // Note: This class is marked with __attribute__((unused)) because all the
313 // work is done in the constructor and destructor, so in the standard
314 // usage example above, the compiler would complain that it's an
315 // unused variable.
316 //
317 // This class is thread-safe.
318
319 class GFLAGS_DLL_DECL FlagSaver {
320 public:
321 FlagSaver();
322 ~FlagSaver();
323
324 private:
325 class FlagSaverImpl* impl_; // we use pimpl here to keep API steady
326
327 FlagSaver(const FlagSaver&); // no copying!
328 void operator=(const FlagSaver&);
329 } ;
330
331 // --------------------------------------------------------------------
332 // Some deprecated or hopefully-soon-to-be-deprecated functions.
333
334 // This is often used for logging. TODO(csilvers): figure out a better way
335 extern GFLAGS_DLL_DECL std::string CommandlineFlagsIntoString();
336 // Usually where this is used, a FlagSaver should be used instead.
337 extern GFLAGS_DLL_DECL bool ReadFlagsFromString(const std::string& flagfileconte nts,
338 const char* prog_name,
339 bool errors_are_fatal); // uses SET_FLAGS_VALUE
340
341 // These let you manually implement --flagfile functionality.
342 // DEPRECATED.
343 extern GFLAGS_DLL_DECL bool AppendFlagsIntoFile(const std::string& filename, con st char* prog_name);
344 extern GFLAGS_DLL_DECL bool SaveCommandFlags(); // actually defined in google.c c !
345 extern GFLAGS_DLL_DECL bool ReadFromFlagsFile(const std::string& filename, const char* prog_name,
346 bool errors_are_fatal); // uses SET_FLAGS_VALUE
347
348
349 // --------------------------------------------------------------------
350 // Useful routines for initializing flags from the environment.
351 // In each case, if 'varname' does not exist in the environment
352 // return defval. If 'varname' does exist but is not valid
353 // (e.g., not a number for an int32 flag), abort with an error.
354 // Otherwise, return the value. NOTE: for booleans, for true use
355 // 't' or 'T' or 'true' or '1', for false 'f' or 'F' or 'false' or '0'.
356
357 extern GFLAGS_DLL_DECL bool BoolFromEnv(const char *varname, bool defval);
358 extern GFLAGS_DLL_DECL int32 Int32FromEnv(const char *varname, int32 defval);
359 extern GFLAGS_DLL_DECL int64 Int64FromEnv(const char *varname, int64 defval);
360 extern GFLAGS_DLL_DECL uint64 Uint64FromEnv(const char *varname, uint64 defval);
361 extern GFLAGS_DLL_DECL double DoubleFromEnv(const char *varname, double defval);
362 extern GFLAGS_DLL_DECL const char *StringFromEnv(const char *varname, const char *defval);
363
364
365 // --------------------------------------------------------------------
366 // The next two functions parse commandlineflags from main():
367
368 // Set the "usage" message for this program. For example:
369 // string usage("This program does nothing. Sample usage:\n");
370 // usage += argv[0] + " <uselessarg1> <uselessarg2>";
371 // SetUsageMessage(usage);
372 // Do not include commandline flags in the usage: we do that for you!
373 // Thread-hostile; meant to be called before any threads are spawned.
374 extern GFLAGS_DLL_DECL void SetUsageMessage(const std::string& usage);
375
376 // Looks for flags in argv and parses them. Rearranges argv to put
377 // flags first, or removes them entirely if remove_flags is true.
378 // If a flag is defined more than once in the command line or flag
379 // file, the last definition is used.
380 // See top-of-file for more details on this function.
381 #ifndef SWIG // In swig, use ParseCommandLineFlagsScript() instead.
382 extern GFLAGS_DLL_DECL uint32 ParseCommandLineFlags(int *argc, char*** argv,
383 bool remove_flags);
384 #endif
385
386
387 // Calls to ParseCommandLineNonHelpFlags and then to
388 // HandleCommandLineHelpFlags can be used instead of a call to
389 // ParseCommandLineFlags during initialization, in order to allow for
390 // changing default values for some FLAGS (via
391 // e.g. SetCommandLineOptionWithMode calls) between the time of
392 // command line parsing and the time of dumping help information for
393 // the flags as a result of command line parsing.
394 // If a flag is defined more than once in the command line or flag
395 // file, the last definition is used.
396 extern GFLAGS_DLL_DECL uint32 ParseCommandLineNonHelpFlags(int *argc, char*** ar gv,
397 bool remove_flags);
398 // This is actually defined in commandlineflags_reporting.cc.
399 // This function is misnamed (it also handles --version, etc.), but
400 // it's too late to change that now. :-(
401 extern GFLAGS_DLL_DECL void HandleCommandLineHelpFlags(); // in commandlinefla gs_reporting.cc
402
403 // Allow command line reparsing. Disables the error normally
404 // generated when an unknown flag is found, since it may be found in a
405 // later parse. Thread-hostile; meant to be called before any threads
406 // are spawned.
407 extern GFLAGS_DLL_DECL void AllowCommandLineReparsing();
408
409 // Reparse the flags that have not yet been recognized.
410 // Only flags registered since the last parse will be recognized.
411 // Any flag value must be provided as part of the argument using "=",
412 // not as a separate command line argument that follows the flag argument.
413 // Intended for handling flags from dynamically loaded libraries,
414 // since their flags are not registered until they are loaded.
415 extern GFLAGS_DLL_DECL void ReparseCommandLineNonHelpFlags();
416
417 // Clean up memory allocated by flags. This is only needed to reduce
418 // the quantity of "potentially leaked" reports emitted by memory
419 // debugging tools such as valgrind. It is not required for normal
420 // operation, or for the perftools heap-checker. It must only be called
421 // when the process is about to exit, and all threads that might
422 // access flags are quiescent. Referencing flags after this is called
423 // will have unexpected consequences. This is not safe to run when
424 // multiple threads might be running: the function is thread-hostile.
425 extern GFLAGS_DLL_DECL void ShutDownCommandLineFlags();
426
427
428 // --------------------------------------------------------------------
429 // Now come the command line flag declaration/definition macros that
430 // will actually be used. They're kind of hairy. A major reason
431 // for this is initialization: we want people to be able to access
432 // variables in global constructors and have that not crash, even if
433 // their global constructor runs before the global constructor here.
434 // (Obviously, we can't guarantee the flags will have the correct
435 // default value in that case, but at least accessing them is safe.)
436 // The only way to do that is have flags point to a static buffer.
437 // So we make one, using a union to ensure proper alignment, and
438 // then use placement-new to actually set up the flag with the
439 // correct default value. In the same vein, we have to worry about
440 // flag access in global destructors, so FlagRegisterer has to be
441 // careful never to destroy the flag-values it constructs.
442 //
443 // Note that when we define a flag variable FLAGS_<name>, we also
444 // preemptively define a junk variable, FLAGS_no<name>. This is to
445 // cause a link-time error if someone tries to define 2 flags with
446 // names like "logging" and "nologging". We do this because a bool
447 // flag FLAG can be set from the command line to true with a "-FLAG"
448 // argument, and to false with a "-noFLAG" argument, and so this can
449 // potentially avert confusion.
450 //
451 // We also put flags into their own namespace. It is purposefully
452 // named in an opaque way that people should have trouble typing
453 // directly. The idea is that DEFINE puts the flag in the weird
454 // namespace, and DECLARE imports the flag from there into the current
455 // namespace. The net result is to force people to use DECLARE to get
456 // access to a flag, rather than saying "extern bool FLAGS_whatever;"
457 // or some such instead. We want this so we can put extra
458 // functionality (like sanity-checking) in DECLARE if we want, and
459 // make sure it is picked up everywhere.
460 //
461 // We also put the type of the variable in the namespace, so that
462 // people can't DECLARE_int32 something that they DEFINE_bool'd
463 // elsewhere.
464
465 class GFLAGS_DLL_DECL FlagRegisterer {
466 public:
467 FlagRegisterer(const char* name, const char* type,
468 const char* help, const char* filename,
469 void* current_storage, void* defvalue_storage);
470 };
471
472 extern bool FlagsTypeWarn(const char *name);
473
474 // If your application #defines STRIP_FLAG_HELP to a non-zero value
475 // before #including this file, we remove the help message from the
476 // binary file. This can reduce the size of the resulting binary
477 // somewhat, and may also be useful for security reasons.
478
479 extern const char kStrippedFlagHelp[];
480
481 }
482
483 #ifndef SWIG // In swig, ignore the main flag declarations
484
485 #if defined(STRIP_FLAG_HELP) && STRIP_FLAG_HELP > 0
486 // Need this construct to avoid the 'defined but not used' warning.
487 #define MAYBE_STRIPPED_HELP(txt) (false ? (txt) : kStrippedFlagHelp)
488 #else
489 #define MAYBE_STRIPPED_HELP(txt) txt
490 #endif
491
492 // Each command-line flag has two variables associated with it: one
493 // with the current value, and one with the default value. However,
494 // we have a third variable, which is where value is assigned; it's a
495 // constant. This guarantees that FLAG_##value is initialized at
496 // static initialization time (e.g. before program-start) rather than
497 // than global construction time (which is after program-start but
498 // before main), at least when 'value' is a compile-time constant. We
499 // use a small trick for the "default value" variable, and call it
500 // FLAGS_no<name>. This serves the second purpose of assuring a
501 // compile error if someone tries to define a flag named no<name>
502 // which is illegal (--foo and --nofoo both affect the "foo" flag).
503 #define DEFINE_VARIABLE(type, shorttype, name, value, help) \
504 namespace fL##shorttype { \
505 static const type FLAGS_nono##name = value; \
506 /* We always want to export defined variables, dll or no */ \
507 GFLAGS_DLL_DEFINE_FLAG type FLAGS_##name = FLAGS_nono##name; \
508 type FLAGS_no##name = FLAGS_nono##name; \
509 static ::google::FlagRegisterer o_##name( \
510 #name, #type, MAYBE_STRIPPED_HELP(help), __FILE__, \
511 &FLAGS_##name, &FLAGS_no##name); \
512 } \
513 using fL##shorttype::FLAGS_##name
514
515 #define DECLARE_VARIABLE(type, shorttype, name) \
516 namespace fL##shorttype { \
517 /* We always want to import declared variables, dll or no */ \
518 extern GFLAGS_DLL_DECLARE_FLAG type FLAGS_##name; \
519 } \
520 using fL##shorttype::FLAGS_##name
521
522 // For DEFINE_bool, we want to do the extra check that the passed-in
523 // value is actually a bool, and not a string or something that can be
524 // coerced to a bool. These declarations (no definition needed!) will
525 // help us do that, and never evaluate From, which is important.
526 // We'll use 'sizeof(IsBool(val))' to distinguish. This code requires
527 // that the compiler have different sizes for bool & double. Since
528 // this is not guaranteed by the standard, we check it with a
529 // compile-time assert (msg[-1] will give a compile-time error).
530 namespace fLB {
531 struct CompileAssert {};
532 typedef CompileAssert expected_sizeof_double_neq_sizeof_bool[
533 (sizeof(double) != sizeof(bool)) ? 1 : -1];
534 template<typename From> GFLAGS_DLL_DECL double IsBoolFlag(const From& from);
535 GFLAGS_DLL_DECL bool IsBoolFlag(bool from);
536 } // namespace fLB
537
538 #define DECLARE_bool(name) DECLARE_VARIABLE(bool, B, name)
539 #define DEFINE_bool(name, val, txt) \
540 namespace fLB { \
541 typedef ::fLB::CompileAssert FLAG_##name##_value_is_not_a_bool[ \
542 (sizeof(::fLB::IsBoolFlag(val)) != sizeof(double)) ? 1 : -1]; \
543 } \
544 DEFINE_VARIABLE(bool, B, name, val, txt)
545
546 #define DECLARE_int32(name) DECLARE_VARIABLE(::google::int32, I, name)
547 #define DEFINE_int32(name,val,txt) DEFINE_VARIABLE(::google::int32, I, name, va l, txt)
548
549 #define DECLARE_int64(name) DECLARE_VARIABLE(::google::int64, I64, name)
550 #define DEFINE_int64(name,val,txt) DEFINE_VARIABLE(::google::int64, I64, name, val, txt)
551
552 #define DECLARE_uint64(name) DECLARE_VARIABLE(::google::uint64, U64, name )
553 #define DEFINE_uint64(name,val,txt) DEFINE_VARIABLE(::google::uint64, U64, name, val, txt)
554
555 #define DECLARE_double(name) DECLARE_VARIABLE(double, D, name)
556 #define DEFINE_double(name, val, txt) DEFINE_VARIABLE(double, D, name, val, txt)
557
558 // Strings are trickier, because they're not a POD, so we can't
559 // construct them at static-initialization time (instead they get
560 // constructed at global-constructor time, which is much later). To
561 // try to avoid crashes in that case, we use a char buffer to store
562 // the string, which we can static-initialize, and then placement-new
563 // into it later. It's not perfect, but the best we can do.
564
565 namespace fLS {
566 // The meaning of "string" might be different between now and when the
567 // macros below get invoked (e.g., if someone is experimenting with
568 // other string implementations that get defined after this file is
569 // included). Save the current meaning now and use it in the macros.
570 typedef std::string clstring;
571
572 inline clstring* dont_pass0toDEFINE_string(char *stringspot,
573 const char *value) {
574 return new(stringspot) clstring(value);
575 }
576 inline clstring* dont_pass0toDEFINE_string(char *stringspot,
577 const clstring &value) {
578 return new(stringspot) clstring(value);
579 }
580 inline clstring* dont_pass0toDEFINE_string(char *stringspot,
581 int value);
582 } // namespace fLS
583
584 #define DECLARE_string(name) namespace fLS { extern GFLAGS_DLL_DECLARE_FLAG ::f LS::clstring& FLAGS_##name; } \
585 using fLS::FLAGS_##name
586
587 // We need to define a var named FLAGS_no##name so people don't define
588 // --string and --nostring. And we need a temporary place to put val
589 // so we don't have to evaluate it twice. Two great needs that go
590 // great together!
591 #define DEFINE_string(name, val, txt) \
592 namespace fLS { \
593 using ::fLS::clstring; \
594 static union { void* align; char s[sizeof(clstring)]; } s_##name[2]; \
595 clstring* const FLAGS_no##name = ::fLS:: \
596 dont_pass0toDEFINE_string(s_##name[0].s, \
597 val); \
598 static ::google::FlagRegisterer o_##name( \
599 #name, "string", MAYBE_STRIPPED_HELP(txt), __FILE__, \
600 s_##name[0].s, new (s_##name[1].s) clstring(*FLAGS_no##name)); \
601 GFLAGS_DLL_DEFINE_FLAG clstring& FLAGS_##name = *FLAGS_no##name; \
602 } \
603 using fLS::FLAGS_##name
604
605 #endif // SWIG
606
607 #endif // GOOGLE_GFLAGS_H_
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