6

iOS 中的断言

 3 years ago
source link: https://kingcos.me/posts/2020/assertion_in_ios/
Go to the source link to view the article. You can view the picture content, updated content and better typesetting reading experience. If the link is broken, please click the button below to view the snapshot at that time.
neoserver,ios ssh client
Date Notes 2020-07-27 首次提交
0

Preface

断言（Assertion）是我们常用于 Debug 时的得力助手，其使得程序得以崩溃在早期，引起我们足够的重视，保障代码质量又不影响用户的体验。本文将简单介绍 iOS 中的断言类型以及使用方式与原理。

assert

NSAssert & NSCAssert

NSAssert

// NSException.h

#if !defined(NS_BLOCK_ASSERTIONS)

#if !defined(_NSAssertBody)
#define NSAssert(condition, desc, ...)	\
    do {				\
	__PRAGMA_PUSH_NO_EXTRA_ARG_WARNINGS \
	if (__builtin_expect(!(condition), 0)) {		\
            NSString *__assert_file__ = [NSString stringWithUTF8String:__FILE__]; \
            __assert_file__ = __assert_file__ ? __assert_file__ : @"<Unknown File>"; \
	    [[NSAssertionHandler currentHandler] handleFailureInMethod:_cmd \
		object:self file:__assert_file__ \
	    	lineNumber:__LINE__ description:(desc), ##__VA_ARGS__]; \
	}				\
        __PRAGMA_POP_NO_EXTRA_ARG_WARNINGS \
    } while(0)
#endif

#if !defined(_NSCAssertBody)
#define NSCAssert(condition, desc, ...) \
    do {				\
	__PRAGMA_PUSH_NO_EXTRA_ARG_WARNINGS \
	if (__builtin_expect(!(condition), 0)) {		\
            NSString *__assert_fn__ = [NSString stringWithUTF8String:__PRETTY_FUNCTION__]; \
            __assert_fn__ = __assert_fn__ ? __assert_fn__ : @"<Unknown Function>"; \
            NSString *__assert_file__ = [NSString stringWithUTF8String:__FILE__]; \
            __assert_file__ = __assert_file__ ? __assert_file__ : @"<Unknown File>"; \
	    [[NSAssertionHandler currentHandler] handleFailureInFunction:__assert_fn__ \
		file:__assert_file__ \
	    	lineNumber:__LINE__ description:(desc), ##__VA_ARGS__]; \
	}				\
        __PRAGMA_POP_NO_EXTRA_ARG_WARNINGS \
    } while(0)
#endif

#else // NS_BLOCK_ASSERTIONS defined

#if !defined(_NSAssertBody)
#define NSAssert(condition, desc, ...) do {} while (0)
#endif

#if !defined(_NSCAssertBody)
#define NSCAssert(condition, desc, ...) do {} while (0)
#endif

#endif

NSParameterAssert

Reference


report

Recommend

About Joyk


Aggregate valuable and interesting links.
Joyk means Joy of geeK