objc/objc_exception.m

   1 #import "objc_tls.h"
   2 #import <stdio.h>
   3
   4 OBJC_EXPORT NSUncaughtExceptionHandler *NSGetUncaughtExceptionHandler(void);
   5 OBJC_EXPORT void NSSetUncaughtExceptionHandler(NSUncaughtExceptionHandler *);
   6
   7 NSUncaughtExceptionHandler *NSThreadUncaughtExceptionHandler(void);
   8 void NSThreadSetUncaughtExceptionHandler(NSUncaughtExceptionHandler *function);
   9
  10 objc_exception_frame *NSThreadCurrentHandler(void) {
  11     return objc_tlsCurrent()->exception_frame;
  12 }
  13
  14 void NSThreadSetCurrentHandler(objc_exception_frame *handler) {
  15     objc_tlsCurrent()->exception_frame = handler;
  16 }
  17
  18 NSUncaughtExceptionHandler *NSThreadUncaughtExceptionHandler(void) {
  19     return objc_tlsCurrent()->uncaught_exception_handler;
  20 }
  21
  22 void NSThreadSetUncaughtExceptionHandler(NSUncaughtExceptionHandler *function) {
  23     objc_tlsCurrent()->uncaught_exception_handler = function;
  24 }
  25
  26 void __NSPushExceptionFrame(objc_exception_frame *frame) {
  27     frame->parent = NSThreadCurrentHandler();
  28     frame->exception = nil;
  29
  30     NSThreadSetCurrentHandler(frame);
  31 }
  32
  33 void __NSPopExceptionFrame(objc_exception_frame *frame) {
  34     NSThreadSetCurrentHandler(frame->parent);
  35 }
  36
  37 static void defaultHandler(id exception) {
  38     __builtin_trap();
  39     fprintf(stderr, "*** Uncaught exception\n");
  40     // fprintf(stderr,"*** Uncaught exception <%s> *** %s\n",[[exception name] cString],[[exception reason] cString]);
  41 }
  42
  43 void _NSRaiseException(id exception) {
  44     objc_exception_frame *top = NSThreadCurrentHandler();
  45
  46     if(top == NULL) {
  47         NSUncaughtExceptionHandler *proc = NSGetUncaughtExceptionHandler();
  48
  49         if(proc == NULL)
  50             defaultHandler(exception);
  51         else
  52             proc(exception);
  53     } else {
  54         NSThreadSetCurrentHandler(top->parent);
  55
  56         top->exception = exception;
  57
  58         longjmp(top->state, 1);
  59     }
  60 }
  61
  62 // Enable that to put back original Cocotron behaviour, where every thread has its own default
  63 // uncaught handler
  64 //#define PER_THREAD_UNHANDLED_EXCEPTION_HANDLER
  65
  66 #ifdef PER_THREAD_UNHANDLED_EXCEPTION_HANDLER
  67
  68 NSUncaughtExceptionHandler *NSGetUncaughtExceptionHandler(void) {
  69     return NSThreadUncaughtExceptionHandler();
  70 }
  71
  72 void NSSetUncaughtExceptionHandler(NSUncaughtExceptionHandler *proc) {
  73     NSThreadSetUncaughtExceptionHandler(proc);
  74 }
  75 #else
  76 static NSUncaughtExceptionHandler *uncaughtExceptionHandler = NULL;
  77
  78 NSUncaughtExceptionHandler *NSGetUncaughtExceptionHandler(void) {
  79     return uncaughtExceptionHandler;
  80 }
  81
  82 void NSSetUncaughtExceptionHandler(NSUncaughtExceptionHandler *proc) {
  83     uncaughtExceptionHandler = proc;
  84 }
  85 #endif
  86
  87 #if !defined(GCC_RUNTIME_3) && !defined(APPLE_RUNTIME_4)
  88
  89 void __gnu_objc_personality_sj0() {
  90     printf("shouldn't get here\n");
  91     abort();
  92 }
  93
  94 void objc_exception_try_enter(void *exceptionFrame) {
  95     __NSPushExceptionFrame((objc_exception_frame *)exceptionFrame);
  96 }
  97
  98 void objc_exception_try_exit(void *exceptionFrame) {
  99     __NSPopExceptionFrame((objc_exception_frame *)exceptionFrame);
 100 }
 101
 102 id objc_exception_extract(void *exceptionFrame) {
 103     objc_exception_frame *frame = (objc_exception_frame *)exceptionFrame;
 104     return (id)frame->exception;
 105 }
 106
 107 void objc_exception_throw(id exception) {
 108     _NSRaiseException(exception);
 109     abort();
 110 }
 111
 112 static BOOL isKindOfClass(id object, Class kindOf) {
 113     Class class = object_getClass(object);
 114
 115     while(object_getClass((id)object_getClass((id) class)) != class) {
 116
 117         if(kindOf == class) {
 118             return YES;
 119         }
 120
 121         class = class_getSuperclass(class);
 122     }
 123
 124     return NO;
 125 }
 126
 127 int objc_exception_match(Class exceptionClass, id exception) {
 128     return isKindOfClass(exception, exceptionClass);
 129 }
 130
 131 #endif