include/wx/debug.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/debug.h
   3 // Purpose:     Misc debug functions and macros
   4 // Author:      Vadim Zeitlin
   5 // Created:     29/01/98
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) 1998-2009 Vadim Zeitlin <vadim@wxwidgets.org>
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef _WX_DEBUG_H_
  12 #define _WX_DEBUG_H_
  13
  14 #if !defined(__WXPALMOS5__) && !defined(__WXWINCE__)
  15     #include  <assert.h>
  16 #endif // systems without assert.h
  17
  18 #include <limits.h>          // for CHAR_BIT used below
  19
  20 #include "wx/chartype.h"     // for __TFILE__ and wxChar
  21 #include "wx/cpp.h"          // for __WXFUNCTION__
  22 #include "wx/dlimpexp.h"     // for WXDLLIMPEXP_FWD_BASE
  23
  24 class WXDLLIMPEXP_FWD_BASE wxString;
  25 class WXDLLIMPEXP_FWD_BASE wxCStrData;
  26
  27 // ----------------------------------------------------------------------------
  28 // Defines controlling the debugging macros
  29 // ----------------------------------------------------------------------------
  30
  31 /*
  32     wxWidgets can be built with several different levels of debug support
  33     specified by the value of wxDEBUG_LEVEL constant:
  34
  35     0:  No assertion macros at all, this should only be used when optimizing
  36         for resource-constrained systems (typically embedded ones).
  37     1:  Default level, most of the assertions are enabled.
  38     2:  Maximal (at least for now): asserts which are "expensive"
  39         (performance-wise) or only make sense for finding errors in wxWidgets
  40         itself, as opposed to bugs in applications using it, are also enabled.
  41  */
  42
  43 // unless wxDEBUG_LEVEL is predefined (by configure or via wx/setup.h under
  44 // Windows), use the default
  45 #if !defined(wxDEBUG_LEVEL)
  46     #define wxDEBUG_LEVEL 1
  47 #endif // !defined(wxDEBUG_LEVEL)
  48
  49 /*
  50     __WXDEBUG__ is defined when wxDEBUG_LEVEL != 0. This is done mostly for
  51     compatibility but it also provides a simpler way to check if asserts and
  52     debug logging is enabled at all.
  53  */
  54 #if wxDEBUG_LEVEL > 0
  55     #ifndef __WXDEBUG__
  56         #define __WXDEBUG__
  57     #endif
  58 #else
  59     #undef __WXDEBUG__
  60 #endif
  61
  62 // Finally there is also a very old WXDEBUG macro not used anywhere at all, it
  63 // is only defined for compatibility.
  64 #ifdef __WXDEBUG__
  65     #if !defined(WXDEBUG) || !WXDEBUG
  66         #undef WXDEBUG
  67         #define WXDEBUG 1
  68     #endif // !WXDEBUG
  69 #endif // __WXDEBUG__
  70
  71 // ----------------------------------------------------------------------------
  72 // Handling assertion failures
  73 // ----------------------------------------------------------------------------
  74
  75 /*
  76     Type for the function called in case of assert failure, see
  77     wxSetAssertHandler().
  78  */
  79 typedef void (*wxAssertHandler_t)(const wxString& file,
  80                                   int line,
  81                                   const wxString& func,
  82                                   const wxString& cond,
  83                                   const wxString& msg);
  84
  85 #if wxDEBUG_LEVEL
  86
  87 // the global assert handler function, if it is NULL asserts don't check their
  88 // conditions
  89 extern WXDLLIMPEXP_DATA_BASE(wxAssertHandler_t) wxTheAssertHandler;
  90
  91 /*
  92     Sets the function to be called in case of assertion failure.
  93
  94     The default assert handler forwards to wxApp::OnAssertFailure() whose
  95     default behaviour is, in turn, to show the standard assertion failure
  96     dialog if a wxApp object exists or shows the same dialog itself directly
  97     otherwise.
  98
  99     While usually it is enough -- and more convenient -- to just override
 100     OnAssertFailure(), to handle all assertion failures, including those
 101     occurring even before wxApp object creation or after its destruction you
 102     need to provide your assertion handler function.
 103
 104     This function also provides a simple way to disable all asserts: simply
 105     pass NULL pointer to it. Doing this will result in not even evaluating
 106     assert conditions at all, avoiding almost all run-time cost of asserts.
 107
 108     Notice that this function is not MT-safe, so you should call it before
 109     starting any other threads.
 110
 111     The return value of this function is the previous assertion handler. It can
 112     be called after any pre-processing by your handler and can also be restored
 113     later if you uninstall your handler.
 114  */
 115 inline wxAssertHandler_t wxSetAssertHandler(wxAssertHandler_t handler)
 116 {
 117     const wxAssertHandler_t old = wxTheAssertHandler;
 118     wxTheAssertHandler = handler;
 119     return old;
 120 }
 121
 122 /*
 123     Reset the default assert handler.
 124
 125     This may be used to enable asserts, which are disabled by default in this
 126     case, for programs built in release build (NDEBUG defined).
 127  */
 128 extern void WXDLLIMPEXP_BASE wxSetDefaultAssertHandler();
 129
 130 #else // !wxDEBUG_LEVEL
 131
 132 // provide empty stubs in case assertions are completely disabled
 133 //
 134 // NB: can't use WXUNUSED() here as we're included from wx/defs.h before it is
 135 //     defined
 136 inline wxAssertHandler_t wxSetAssertHandler(wxAssertHandler_t /* handler */)
 137 {
 138     return NULL;
 139 }
 140
 141 inline void wxSetDefaultAssertHandler() { }
 142
 143 #endif // wxDEBUG_LEVEL/!wxDEBUG_LEVEL
 144
 145 // simply a synonym for wxSetAssertHandler(NULL)
 146 inline void wxDisableAsserts() { wxSetAssertHandler(NULL); }
 147
 148 /*
 149     A macro which disables asserts for applications compiled in release build.
 150
 151     By default, IMPLEMENT_APP (or rather IMPLEMENT_WXWIN_MAIN) disable the
 152     asserts in the applications compiled in the release build by calling this.
 153     It does nothing if NDEBUG is not defined.
 154  */
 155 #ifdef NDEBUG
 156     #define wxDISABLE_ASSERTS_IN_RELEASE_BUILD() wxDisableAsserts()
 157 #else
 158     #define wxDISABLE_ASSERTS_IN_RELEASE_BUILD()
 159 #endif
 160
 161 #if wxDEBUG_LEVEL
 162
 163 /*
 164     wxOnAssert() is used by the debugging macros defined below. Different
 165     overloads are needed because these macros can be used with or without _T().
 166
 167     All of them are implemented in src/common/appcmn.cpp and unconditionally
 168     call wxTheAssertHandler so the caller must check that it is non-NULL
 169     (assert macros do it).
 170  */
 171
 172 #if wxUSE_UNICODE
 173
 174 // these overloads are the ones typically used by debugging macros: we have to
 175 // provide wxChar* msg version because it's common to use _T() in the macros
 176 // and finally, we can't use const wx(char)* msg = NULL, because that would
 177 // be ambiguous
 178 //
 179 // also notice that these functions can't be inline as wxString is not defined
 180 // yet (and can't be as wxString code itself may use assertions)
 181 extern void WXDLLIMPEXP_BASE wxOnAssert(const char *file,
 182                                         int line,
 183                                         const char *func,
 184                                         const char *cond);
 185
 186 extern void WXDLLIMPEXP_BASE wxOnAssert(const char *file,
 187                                         int line,
 188                                         const char *func,
 189                                         const char *cond,
 190                                         const char *msg);
 191
 192 extern void WXDLLIMPEXP_BASE wxOnAssert(const char *file,
 193                                         int line,
 194                                         const char *func,
 195                                         const char *cond,
 196                                         const wxChar *msg);
 197 #endif /* wxUSE_UNICODE */
 198
 199 // this version is for compatibility with wx 2.8 Unicode build only, we don't
 200 // use it ourselves any more except in ANSI-only build in which case it is all
 201 // we need
 202 extern void WXDLLIMPEXP_BASE wxOnAssert(const wxChar *file,
 203                                         int line,
 204                                         const char *func,
 205                                         const wxChar *cond,
 206                                         const wxChar *msg = NULL);
 207
 208 // these overloads work when msg passed to debug macro is a string and we
 209 // also have to provide wxCStrData overload to resolve ambiguity which would
 210 // otherwise arise from wxASSERT( s.c_str() )
 211 extern void WXDLLIMPEXP_BASE wxOnAssert(const wxString& file,
 212                                         int line,
 213                                         const wxString& func,
 214                                         const wxString& cond,
 215                                         const wxString& msg);
 216
 217 extern void WXDLLIMPEXP_BASE wxOnAssert(const wxString& file,
 218                                         int line,
 219                                         const wxString& func,
 220                                         const wxString& cond);
 221
 222 extern void WXDLLIMPEXP_BASE wxOnAssert(const char *file,
 223                                         int line,
 224                                         const char *func,
 225                                         const char *cond,
 226                                         const wxCStrData& msg);
 227
 228 extern void WXDLLIMPEXP_BASE wxOnAssert(const char *file,
 229                                         int line,
 230                                         const char *func,
 231                                         const char *cond,
 232                                         const wxString& msg);
 233
 234 #endif // wxDEBUG_LEVEL
 235
 236
 237 // ----------------------------------------------------------------------------
 238 // Debugging macros
 239 // ----------------------------------------------------------------------------
 240
 241 /*
 242     Assertion macros: check if the condition is true and call assert handler
 243     (which will by default notify the user about failure) if it isn't.
 244
 245     wxASSERT and wxFAIL macros as well as wxTrap() function do nothing at all
 246     if wxDEBUG_LEVEL is 0 however they do check their conditions at default
 247     debug level 1, unlike the previous wxWidgets versions.
 248
 249     wxASSERT_LEVEL_2 is meant to be used for "expensive" asserts which should
 250     normally be disabled because they have a big impact on performance and so
 251     this macro only does anything if wxDEBUG_LEVEL >= 2.
 252  */
 253 #if wxDEBUG_LEVEL
 254     // call this function to break into the debugger unconditionally (assuming
 255     // the program is running under debugger, of course)
 256     extern void WXDLLIMPEXP_BASE wxTrap();
 257
 258     // assert checks if the condition is true and calls the assert handler with
 259     // the provided message if it isn't
 260     //
 261     // NB: the macro is defined like this to ensure that nested if/else
 262     //     statements containing it are compiled in the same way whether it is
 263     //     defined as empty or not; also notice that we can't use ";" instead
 264     //     of "{}" as some compilers warn about "possible unwanted ;" then
 265     #define wxASSERT_MSG(cond, msg)                                           \
 266         if ( !wxTheAssertHandler || (cond) )                                  \
 267         {}                                                                    \
 268         else                                                                  \
 269             wxOnAssert(__FILE__, __LINE__, __WXFUNCTION__, #cond, msg)
 270
 271     // a version without any additional message, don't use unless condition
 272     // itself is fully self-explanatory
 273     #define wxASSERT(cond) wxASSERT_MSG(cond, (const char*)NULL)
 274
 275     // wxFAIL is a special form of assert: it always triggers (and so is
 276     // usually used in normally unreachable code)
 277     #define wxFAIL_COND_MSG(cond, msg) \
 278         if ( !wxTheAssertHandler )                                            \
 279         {}                                                                    \
 280         else                                                                  \
 281             wxOnAssert(__FILE__, __LINE__,  __WXFUNCTION__, cond, msg)
 282     #define wxFAIL_MSG(msg) wxFAIL_COND_MSG("Assert failure", msg)
 283     #define wxFAIL wxFAIL_MSG((const char*)NULL)
 284 #else // !wxDEBUG_LEVEL
 285     #define wxTrap()
 286
 287     #define wxASSERT(cond)
 288     #define wxASSERT_MSG(cond, msg)
 289     #define wxFAIL
 290     #define wxFAIL_MSG(msg)
 291     #define wxFAIL_COND_MSG(cond, msg)
 292 #endif  // wxDEBUG_LEVEL
 293
 294 #if wxDEBUG_LEVEL >= 2
 295     #define wxASSERT_LEVEL_2_MSG(cond, msg) wxASSERT_MSG(cond, msg)
 296     #define wxASSERT_LEVEL_2(cond) wxASSERT(cond)
 297 #else // wxDEBUG_LEVEL < 2
 298     #define wxASSERT_LEVEL_2_MSG(cond, msg)
 299     #define wxASSERT_LEVEL_2(cond)
 300 #endif
 301
 302
 303 /*
 304     wxCHECK macros always check their conditions, setting debug level to 0 only
 305     makes them silent in case of failure, otherwise -- including at default
 306     debug level 1 -- they call the assert handler if the condition is false
 307
 308     They are supposed to be used only in invalid situation: for example, an
 309     invalid parameter (e.g. a NULL pointer) is passed to a function. Instead of
 310     dereferencing it and causing core dump the function might use
 311
 312         wxCHECK_RET( p != NULL, "pointer can't be NULL" )
 313 */
 314
 315 // the generic macro: takes the condition to check, the statement to be execute
 316 // in case the condition is false and the message to pass to the assert handler
 317 #define wxCHECK2_MSG(cond, op, msg)                                       \
 318     if ( cond )                                                           \
 319     {}                                                                    \
 320     else                                                                  \
 321     {                                                                     \
 322         wxFAIL_COND_MSG(#cond, msg);                                      \
 323         op;                                                               \
 324     }                                                                     \
 325     struct wxDummyCheckStruct /* just to force a semicolon */
 326
 327 // check which returns with the specified return code if the condition fails
 328 #define wxCHECK_MSG(cond, rc, msg)   wxCHECK2_MSG(cond, return rc, msg)
 329
 330 // check that expression is true, "return" if not (also FAILs in debug mode)
 331 #define wxCHECK(cond, rc)            wxCHECK_MSG(cond, rc, (const char*)NULL)
 332
 333 // check that expression is true, perform op if not
 334 #define wxCHECK2(cond, op)           wxCHECK2_MSG(cond, op, (const char*)NULL)
 335
 336 // special form of wxCHECK2: as wxCHECK, but for use in void functions
 337 //
 338 // NB: there is only one form (with msg parameter) and it's intentional:
 339 //     there is no other way to tell the caller what exactly went wrong
 340 //     from the void function (of course, the function shouldn't be void
 341 //     to begin with...)
 342 #define wxCHECK_RET(cond, msg)       wxCHECK2_MSG(cond, return, msg)
 343
 344
 345 // ----------------------------------------------------------------------------
 346 // Compile time asserts
 347 //
 348 // Unlike the normal assert and related macros above which are checked during
 349 // the program run-time the macros below will result in a compilation error if
 350 // the condition they check is false. This is usually used to check the
 351 // expressions containing sizeof()s which cannot be tested with the
 352 // preprocessor. If you can use the #if's, do use them as you can give a more
 353 // detailed error message then.
 354 // ----------------------------------------------------------------------------
 355
 356 /*
 357   How this works (you don't have to understand it to be able to use the
 358   macros): we rely on the fact that it is invalid to define a named bit field
 359   in a struct of width 0. All the rest are just the hacks to minimize the
 360   possibility of the compiler warnings when compiling this macro: in
 361   particular, this is why we define a struct and not an object (which would
 362   result in a warning about unused variable) and a named struct (otherwise we'd
 363   get a warning about an unnamed struct not used to define an object!).
 364  */
 365
 366 #define wxMAKE_UNIQUE_ASSERT_NAME           wxMAKE_UNIQUE_NAME(wxAssert_)
 367
 368 /*
 369   The second argument of this macro must be a valid C++ identifier and not a
 370   string. I.e. you should use it like this:
 371
 372     wxCOMPILE_TIME_ASSERT( sizeof(int) >= 2, YourIntsAreTooSmall );
 373
 374  It may be used both within a function and in the global scope.
 375 */
 376 #if defined(__WATCOMC__)
 377     /* avoid "unused symbol" warning */
 378     #define wxCOMPILE_TIME_ASSERT(expr, msg) \
 379         class wxMAKE_UNIQUE_ASSERT_NAME { \
 380           unsigned int msg: expr; \
 381           wxMAKE_UNIQUE_ASSERT_NAME() { wxUnusedVar(msg); } \
 382         }
 383 #elif defined( __VMS )
 384 namespace wxdebug{
 385
 386 // HP aCC cannot deal with missing names for template value parameters
 387 template <bool x> struct STATIC_ASSERTION_FAILURE;
 388
 389 template <> struct STATIC_ASSERTION_FAILURE<true> { enum { value = 1 }; };
 390
 391 // HP aCC cannot deal with missing names for template value parameters
 392 template<int x> struct static_assert_test{};
 393
 394 }
 395     #define WX_JOIN( X, Y ) X##Y
 396     #define WX_STATIC_ASSERT_BOOL_CAST(x) (bool)(x)
 397     #define wxCOMPILE_TIME_ASSERT(expr, msg) \
 398        typedef ::wxdebug::static_assert_test<\
 399           sizeof(::wxdebug::STATIC_ASSERTION_FAILURE< WX_STATIC_ASSERT_BOOL_CAST( expr ) >)>\
 400             WX_JOIN(wx_static_assert_typedef_, __LINE__)
 401 #else
 402     #define wxCOMPILE_TIME_ASSERT(expr, msg) \
 403         struct wxMAKE_UNIQUE_ASSERT_NAME { unsigned int msg: expr; }
 404 #endif
 405
 406 /*
 407    When using VC++ 6 with "Edit and Continue" on, the compiler completely
 408    mishandles __LINE__ and so wxCOMPILE_TIME_ASSERT() doesn't work, provide a
 409    way to make "unique" assert names by specifying a unique prefix explicitly
 410  */
 411 #define wxMAKE_UNIQUE_ASSERT_NAME2(text) wxCONCAT(wxAssert_, text)
 412
 413 #define wxCOMPILE_TIME_ASSERT2(expr, msg, text) \
 414     struct wxMAKE_UNIQUE_ASSERT_NAME2(text) { unsigned int msg: expr; }
 415
 416 // helpers for wxCOMPILE_TIME_ASSERT below, for private use only
 417 #define wxMAKE_BITSIZE_MSG(type, size) type ## SmallerThan ## size ## Bits
 418
 419 // a special case of compile time assert: check that the size of the given type
 420 // is at least the given number of bits
 421 #define wxASSERT_MIN_BITSIZE(type, size) \
 422     wxCOMPILE_TIME_ASSERT(sizeof(type) * CHAR_BIT >= size, \
 423                           wxMAKE_BITSIZE_MSG(type, size))
 424
 425
 426 // ----------------------------------------------------------------------------
 427 // other miscellaneous debugger-related functions
 428 // ----------------------------------------------------------------------------
 429
 430 /*
 431     Return true if we're running under debugger.
 432
 433     Currently this only really works under Win32 and Mac in CodeWarrior builds,
 434     it always returns false in other cases.
 435  */
 436 #if defined(__WXMAC__) || defined(__WIN32__)
 437     extern bool WXDLLIMPEXP_BASE wxIsDebuggerRunning();
 438 #else // !Mac
 439     inline bool wxIsDebuggerRunning() { return false; }
 440 #endif // Mac/!Mac
 441
 442 // An assert helper used to avoid warning when testing constant expressions,
 443 // i.e. wxASSERT( sizeof(int) == 4 ) can generate a compiler warning about
 444 // expression being always true, but not using
 445 // wxASSERT( wxAssertIsEqual(sizeof(int), 4) )
 446 //
 447 // NB: this is made obsolete by wxCOMPILE_TIME_ASSERT() and should no
 448 //     longer be used.
 449 extern bool WXDLLIMPEXP_BASE wxAssertIsEqual(int x, int y);
 450
 451 // Use of wxFalse instead of false suppresses compiler warnings about testing
 452 // constant expression
 453 extern WXDLLIMPEXP_DATA_BASE(const bool) wxFalse;
 454
 455 #define wxAssertFailure wxFalse
 456
 457 // This is similar to WXUNUSED() and useful for parameters which are only used
 458 // in assertions.
 459 #if wxDEBUG_LEVEL
 460     #define WXUNUSED_UNLESS_DEBUG(param)  param
 461 #else
 462     #define WXUNUSED_UNLESS_DEBUG(param)  WXUNUSED(param)
 463 #endif
 464
 465
 466 #endif // _WX_DEBUG_H_