1 /*
2   Simple DirectMedia Layer
3   Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
4 
5   This software is provided 'as-is', without any express or implied
6   warranty.  In no event will the authors be held liable for any damages
7   arising from the use of this software.
8 
9   Permission is granted to anyone to use this software for any purpose,
10   including commercial applications, and to alter it and redistribute it
11   freely, subject to the following restrictions:
12 
13   1. The origin of this software must not be misrepresented; you must not
14      claim that you wrote the original software. If you use this software
15      in a product, an acknowledgment in the product documentation would be
16      appreciated but is not required.
17   2. Altered source versions must be plainly marked as such, and must not be
18      misrepresented as being the original software.
19   3. This notice may not be removed or altered from any source distribution.
20 */
21 
22 #ifndef SDL_assert_h_
23 #define SDL_assert_h_
24 
25 #include "SDL_config.h"
26 
27 #include "begin_code.h"
28 /* Set up for C function definitions, even when using C++ */
29 #ifdef __cplusplus
30 extern "C" {
31 #endif
32 
33 #ifndef SDL_ASSERT_LEVEL
34 #ifdef SDL_DEFAULT_ASSERT_LEVEL
35 #define SDL_ASSERT_LEVEL SDL_DEFAULT_ASSERT_LEVEL
36 #elif defined(_DEBUG) || defined(DEBUG) || \
37       (defined(__GNUC__) && !defined(__OPTIMIZE__))
38 #define SDL_ASSERT_LEVEL 2
39 #else
40 #define SDL_ASSERT_LEVEL 1
41 #endif
42 #endif /* SDL_ASSERT_LEVEL */
43 
44 /*
45 These are macros and not first class functions so that the debugger breaks
46 on the assertion line and not in some random guts of SDL, and so each
47 assert can have unique static variables associated with it.
48 */
49 
50 #if defined(_MSC_VER)
51 /* Don't include intrin.h here because it contains C++ code */
52     extern void __cdecl __debugbreak(void);
53     #define SDL_TriggerBreakpoint() __debugbreak()
54 #elif ( (!defined(__NACL__)) && ((defined(__GNUC__) || defined(__clang__)) && (defined(__i386__) || defined(__x86_64__))) )
55     #define SDL_TriggerBreakpoint() __asm__ __volatile__ ( "int $3\n\t" )
56 #elif defined(__386__) && defined(__WATCOMC__)
57     #define SDL_TriggerBreakpoint() { _asm { int 0x03 } }
58 #elif defined(HAVE_SIGNAL_H) && !defined(__WATCOMC__)
59     #include <signal.h>
60     #define SDL_TriggerBreakpoint() raise(SIGTRAP)
61 #else
62     /* How do we trigger breakpoints on this platform? */
63     #define SDL_TriggerBreakpoint()
64 #endif
65 
66 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 supports __func__ as a standard. */
67 #   define SDL_FUNCTION __func__
68 #elif ((__GNUC__ >= 2) || defined(_MSC_VER) || defined (__WATCOMC__))
69 #   define SDL_FUNCTION __FUNCTION__
70 #else
71 #   define SDL_FUNCTION "???"
72 #endif
73 #define SDL_FILE    __FILE__
74 #define SDL_LINE    __LINE__
75 
76 /*
77 sizeof (x) makes the compiler still parse the expression even without
78 assertions enabled, so the code is always checked at compile time, but
79 doesn't actually generate code for it, so there are no side effects or
80 expensive checks at run time, just the constant size of what x WOULD be,
81 which presumably gets optimized out as unused.
82 This also solves the problem of...
83 
84     int somevalue = blah();
85     SDL_assert(somevalue == 1);
86 
87 ...which would cause compiles to complain that somevalue is unused if we
88 disable assertions.
89 */
90 
91 /* "while (0,0)" fools Microsoft's compiler's /W4 warning level into thinking
92     this condition isn't constant. And looks like an owl's face! */
93 #ifdef _MSC_VER  /* stupid /W4 warnings. */
94 #define SDL_NULL_WHILE_LOOP_CONDITION (0,0)
95 #else
96 #define SDL_NULL_WHILE_LOOP_CONDITION (0)
97 #endif
98 
99 #define SDL_disabled_assert(condition) \
100     do { (void) sizeof ((condition)); } while (SDL_NULL_WHILE_LOOP_CONDITION)
101 
102 typedef enum
103 {
104     SDL_ASSERTION_RETRY,  /**< Retry the assert immediately. */
105     SDL_ASSERTION_BREAK,  /**< Make the debugger trigger a breakpoint. */
106     SDL_ASSERTION_ABORT,  /**< Terminate the program. */
107     SDL_ASSERTION_IGNORE,  /**< Ignore the assert. */
108     SDL_ASSERTION_ALWAYS_IGNORE  /**< Ignore the assert from now on. */
109 } SDL_AssertState;
110 
111 typedef struct SDL_AssertData
112 {
113     int always_ignore;
114     unsigned int trigger_count;
115     const char *condition;
116     const char *filename;
117     int linenum;
118     const char *function;
119     const struct SDL_AssertData *next;
120 } SDL_AssertData;
121 
122 #if (SDL_ASSERT_LEVEL > 0)
123 
124 /* Never call this directly. Use the SDL_assert* macros. */
125 extern DECLSPEC SDL_AssertState SDLCALL SDL_ReportAssertion(SDL_AssertData *,
126                                                              const char *,
127                                                              const char *, int)
128 #if defined(__clang__)
129 #if __has_feature(attribute_analyzer_noreturn)
130 /* this tells Clang's static analysis that we're a custom assert function,
131    and that the analyzer should assume the condition was always true past this
132    SDL_assert test. */
133    __attribute__((analyzer_noreturn))
134 #endif
135 #endif
136 ;
137 
138 /* the do {} while(0) avoids dangling else problems:
139     if (x) SDL_assert(y); else blah();
140        ... without the do/while, the "else" could attach to this macro's "if".
141    We try to handle just the minimum we need here in a macro...the loop,
142    the static vars, and break points. The heavy lifting is handled in
143    SDL_ReportAssertion(), in SDL_assert.c.
144 */
145 #define SDL_enabled_assert(condition) \
146     do { \
147         while ( !(condition) ) { \
148             static struct SDL_AssertData sdl_assert_data = { \
149                 0, 0, #condition, 0, 0, 0, 0 \
150             }; \
151             const SDL_AssertState sdl_assert_state = SDL_ReportAssertion(&sdl_assert_data, SDL_FUNCTION, SDL_FILE, SDL_LINE); \
152             if (sdl_assert_state == SDL_ASSERTION_RETRY) { \
153                 continue; /* go again. */ \
154             } else if (sdl_assert_state == SDL_ASSERTION_BREAK) { \
155                 SDL_TriggerBreakpoint(); \
156             } \
157             break; /* not retrying. */ \
158         } \
159     } while (SDL_NULL_WHILE_LOOP_CONDITION)
160 
161 #endif  /* enabled assertions support code */
162 
163 /* Enable various levels of assertions. */
164 #if SDL_ASSERT_LEVEL == 0   /* assertions disabled */
165 #   define SDL_assert(condition) SDL_disabled_assert(condition)
166 #   define SDL_assert_release(condition) SDL_disabled_assert(condition)
167 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
168 #elif SDL_ASSERT_LEVEL == 1  /* release settings. */
169 #   define SDL_assert(condition) SDL_disabled_assert(condition)
170 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
171 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
172 #elif SDL_ASSERT_LEVEL == 2  /* normal settings. */
173 #   define SDL_assert(condition) SDL_enabled_assert(condition)
174 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
175 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
176 #elif SDL_ASSERT_LEVEL == 3  /* paranoid settings. */
177 #   define SDL_assert(condition) SDL_enabled_assert(condition)
178 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
179 #   define SDL_assert_paranoid(condition) SDL_enabled_assert(condition)
180 #else
181 #   error Unknown assertion level.
182 #endif
183 
184 /* this assertion is never disabled at any level. */
185 #define SDL_assert_always(condition) SDL_enabled_assert(condition)
186 
187 
188 typedef SDL_AssertState (SDLCALL *SDL_AssertionHandler)(
189                                  const SDL_AssertData* data, void* userdata);
190 
191 /**
192  *  \brief Set an application-defined assertion handler.
193  *
194  *  This allows an app to show its own assertion UI and/or force the
195  *  response to an assertion failure. If the app doesn't provide this, SDL
196  *  will try to do the right thing, popping up a system-specific GUI dialog,
197  *  and probably minimizing any fullscreen windows.
198  *
199  *  This callback may fire from any thread, but it runs wrapped in a mutex, so
200  *  it will only fire from one thread at a time.
201  *
202  *  Setting the callback to NULL restores SDL's original internal handler.
203  *
204  *  This callback is NOT reset to SDL's internal handler upon SDL_Quit()!
205  *
206  *  Return SDL_AssertState value of how to handle the assertion failure.
207  *
208  *  \param handler Callback function, called when an assertion fails.
209  *  \param userdata A pointer passed to the callback as-is.
210  */
211 extern DECLSPEC void SDLCALL SDL_SetAssertionHandler(
212                                             SDL_AssertionHandler handler,
213                                             void *userdata);
214 
215 /**
216  *  \brief Get the default assertion handler.
217  *
218  *  This returns the function pointer that is called by default when an
219  *   assertion is triggered. This is an internal function provided by SDL,
220  *   that is used for assertions when SDL_SetAssertionHandler() hasn't been
221  *   used to provide a different function.
222  *
223  *  \return The default SDL_AssertionHandler that is called when an assert triggers.
224  */
225 extern DECLSPEC SDL_AssertionHandler SDLCALL SDL_GetDefaultAssertionHandler(void);
226 
227 /**
228  *  \brief Get the current assertion handler.
229  *
230  *  This returns the function pointer that is called when an assertion is
231  *   triggered. This is either the value last passed to
232  *   SDL_SetAssertionHandler(), or if no application-specified function is
233  *   set, is equivalent to calling SDL_GetDefaultAssertionHandler().
234  *
235  *   \param puserdata Pointer to a void*, which will store the "userdata"
236  *                    pointer that was passed to SDL_SetAssertionHandler().
237  *                    This value will always be NULL for the default handler.
238  *                    If you don't care about this data, it is safe to pass
239  *                    a NULL pointer to this function to ignore it.
240  *  \return The SDL_AssertionHandler that is called when an assert triggers.
241  */
242 extern DECLSPEC SDL_AssertionHandler SDLCALL SDL_GetAssertionHandler(void **puserdata);
243 
244 /**
245  *  \brief Get a list of all assertion failures.
246  *
247  *  Get all assertions triggered since last call to SDL_ResetAssertionReport(),
248  *  or the start of the program.
249  *
250  *  The proper way to examine this data looks something like this:
251  *
252  *  <code>
253  *  const SDL_AssertData *item = SDL_GetAssertionReport();
254  *  while (item) {
255  *      printf("'%s', %s (%s:%d), triggered %u times, always ignore: %s.\\n",
256  *             item->condition, item->function, item->filename,
257  *             item->linenum, item->trigger_count,
258  *             item->always_ignore ? "yes" : "no");
259  *      item = item->next;
260  *  }
261  *  </code>
262  *
263  *  \return List of all assertions.
264  *  \sa SDL_ResetAssertionReport
265  */
266 extern DECLSPEC const SDL_AssertData * SDLCALL SDL_GetAssertionReport(void);
267 
268 /**
269  *  \brief Reset the list of all assertion failures.
270  *
271  *  Reset list of all assertions triggered.
272  *
273  *  \sa SDL_GetAssertionReport
274  */
275 extern DECLSPEC void SDLCALL SDL_ResetAssertionReport(void);
276 
277 
278 /* these had wrong naming conventions until 2.0.4. Please update your app! */
279 #define SDL_assert_state SDL_AssertState
280 #define SDL_assert_data SDL_AssertData
281 
282 
283 /* Ends C function definitions when using C++ */
284 #ifdef __cplusplus
285 }
286 #endif
287 #include "close_code.h"
288 
289 #endif /* SDL_assert_h_ */
290 
291 /* vi: set ts=4 sw=4 expandtab: */
292