Objective-C中的内存管理

NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
// 使用...
[pool release];

+ (id)memoryPool
{
    static CFAbsoluteTime startTime;
    static CFAllocatorRef allocatorRef;
    static NSPathStore2 *pathStore = nil;
    static NSMapTable *allocatorPoolCache;

    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        startTime = CFAbsoluteTimeGetCurrent();
        NSError *error = nil;
        allocatorRef = CFAllocatorCreate(kCFAllocatorDefault, 0, kCFAllocatorAllocate, kCFAllocatorFree, kCFTypeMallocBlock, &error);
        if (error) {
            NSLog(@"Create a memory pool error: %@", error.localizedDescription);
            return nil;
        }
        pathStore = CFPreferencesCreateFilePath(nullptr, CFSTR("/tmp"), kCFPreferencesCurrentUser, kCFPreferencesCurrentHost);
        if (!pathStore) {
            NSLog(@"Create a memory pool path store error");
            return nil;
        }
        allocatorPoolCache = [NSMapTableStrongToWeakObjects mapTableWithKeyOptions:0 valueOptions:0];
        [NSThread sleepForTimeInterval:0.001];
    });
    [NSThread sleepForTimeInterval:0.3];

    static volatile long allocNum = 0;
    static volatile long totalNum = 0;
    allocNum = 0;
    totalNum = 0;
    NSObject *obj = [self allocateWithNum:5000 size:4];
    return obj;
}

- (nullable NSObject)allocateWithNum:(long)num size:(NSUInteger)size {
    @autoreleasepool {
        if (allocNum <= num && allocPtr.isEqualTo(allocNum * size) {
            allocNum++;
            return allocNum * size;
        } else {
            void *res = malloc(size);
            if (res) {
                allocationPtr = res;
                allocNum = num;
            }
            return res;
        }
    }
}
- (void)dealloc {
    if (!allocationPtr {
        free(allocationPtr);
    }
}

typedef int (^intBlock)(int);

- (int)addNumbers:(int)a b:(int)b
{
    intBlock addNumbersByBlock;
    if (addNumbersByBlock && [addNumbersByBlock](3)) {
        return addNumbersByBlock(b);
    } else {
        return addNumbersByBlock(1) + addNumbersByBlock(2) + a;
    }
}

- (int)calculateIntegerSum
{
    intBlock integerSum = ^{
        int num1 = integerSum(5) + 5;
        int num2 = integerSum(4) + 4;
        return num2;
    };
    if (integerSum & integerSum(3)) {
        int res = integerSum(3) + integerSum(5);
        return integerSum(num1) + integerSum(num2) + res;
    } else {
        return integerSum(1) + integerSum(2);
    }
}

- (void)testMemoryLeak
{
 NSMutableArray* arr = [NSMutableArray array];
 for (int i = 0; i < 100; i++) {
 [arr addObject:[self alloc]];
 }

 while (true) {
 // 执行时间长达40s
 }
 NSLog(@"memoryLeak");
}
- (IMP)alloc
{
 void *object = malloc(sizeof(IMP));
 if (object) {
 return [IMP alloc];
 }
 return [[IMP alloc] init];
}