用于将整数添加到 nsmuatablearray FMDB/EGODB 的编译器指令防御性编程
当用户尝试将 int 添加到 nsmutablearray 时，我想抛出一条警告消息，
基本上任何包含非 nsstring / nsnumber 值的插入语句都会导致运行时崩溃。当你输入 %@ 而不是 %d NSLog(int); 时，这与你得到的崩溃完全相同。 崩溃没问题，但我想向用户抛出一条友好的“致命”消息。
到目前为止，我已经用 isKindOfClass NSObject 进行了尝试捕获，但整数正在溜走。
#define FATAL_MSG "FATAL: object is not an NSObject subclass. Are you using int? use [NSNumber numberWithInt:1] \n"
#define VAToArray(firstarg) ({\
NSMutableArray* valistArray = [NSMutableArray array];\
id obj = nil;\
va_list arguments;\
va_start(arguments, sql);\
@try { \
while ((obj = va_arg(arguments, id))) {\
if([obj isKindOfClass:[NSObject class]]) [valistArray addObject:obj];\
else printf(FATAL_MSG); \
}\
} \
@catch(NSException *exception){ \
printf(FATAL_MSG); \
} \
va_end(arguments);\
valistArray;\
})
- (void)test:(NSString*)sql,... {
NSLog(@"VAToArray :%@",VAToArray(sql)); }
它时调用它
[self test:@"str",@"test",nil];
// 然后当我调用 [自测试：@"str",2,nil];
抛出错误消息。
I would like to throw a warning message when users try to add an int to an nsmutablearray
basically any insert statement that includes values that are not nsstring / nsnumber cause run time crashes. It's exactly the same crash you get when you type %@ instead of %d NSLog(int);
The crash is ok, but I want to throw a friendly 'FATAL' message to user.
so far I have this try catch with isKindOfClass NSObject but ints are slipping through.
#define FATAL_MSG "FATAL: object is not an NSObject subclass. Are you using int? use [NSNumber numberWithInt:1] \n"
#define VAToArray(firstarg) ({\
NSMutableArray* valistArray = [NSMutableArray array];\
id obj = nil;\
va_list arguments;\
va_start(arguments, sql);\
@try { \
while ((obj = va_arg(arguments, id))) {\
if([obj isKindOfClass:[NSObject class]]) [valistArray addObject:obj];\
else printf(FATAL_MSG); \
}\
} \
@catch(NSException *exception){ \
printf(FATAL_MSG); \
} \
va_end(arguments);\
valistArray;\
})
- (void)test:(NSString*)sql,... {
NSLog(@"VAToArray :%@",VAToArray(sql));
}
// then call this
[self test:@"str",@"test",nil];
when I call this
[self test:@"str",2,nil];
throw the error message.
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使用 isKindOfClass 来测试它是否是 NSObject 是行不通的。崩溃的原因是它将 int 视为指向对象的指针，但它是一个无效指针。调用 isKindOfClass 会导致相同的错误。由于应用程序因无效指针而崩溃，因此不会引发异常，因此 @try-@catch 语句也不会捕获它。基本上，您必须相信用户会听取编译器的指令，并且不会在需要对象的地方使用 int 。
Using isKindOfClass to test if it is an NSObject won't work. The reason for the crash is that it is treating the int as a pointer to a object, but it is an invalid pointer. Calling isKindOfClass would cause the same error. Since the application crashes from an invalid pointer, there is no exception thrown, so the @try-@catch statement won't catch it either. Basically, you have to trust that the user will listen to the compiler and not use an int where an object is expected.