Question

我有一个NSMutableArray在enumerateObjects循环中填充了值。大约第4或第5次填充MutableArray的函数被调用，我的堆栈出现SIGSEGV错误

0   libobjc.A.dylib 0x39e7e626 objc_msgSend + 6
1   CoreFoundation 0x2f663dc9 -[__NSArrayM dealloc] + 154
2   libobjc.A.dylib 0x39e83b6b _ZN11objc_object17sidetable_releaseEb + 172
3   MyAppName 0x0004bdff -[BluetoothManager(DataParse) processResponse:] (BluetoothManager+DataParse.m:231)

设置

一个appDelegate，它有一个指向BluetoothManager实例的强指针。
BluetoothManager类上的函数调用，BluetoothManager上的签名为processResponse:，每次在外围代理上调用didUpdateValueForCharacteristic:时都会调用该函数。
processBleResponse:获取NSData blob并将其转换为NSNumbers数组

我注意到第4次左右调用processReponse:，我存储所有NSNumber的可变数组在其自己的enumerateObjects循环中得到了malloc。

我使用重复的NSTimer来模拟测试，该NSTimer调用processResponse：每30-40秒有一些虚拟数据，但是在循环的每几次迭代之后错误都是可重现的。该应用程序的整体内存使用量不超过45MB

// method on BluetoothManager class 
- (void)processBleResponse:(NSData *)myData
{   
__block float baseValue = 34.500;
__block float incrementValue = 0.0500;

// convert hex data into array of 10 binary "strings"
NSArray *individualBinaryArray = [self extractBinaryValues:myData];

// Extract temperature fields
NSIndexSet *relevantIndices = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(1, individualBinaryArray.count - 1)];

__block NSUInteger indexOfFailure = NSNotFound;
NSMutableArray *decimalValues = [[NSMutableArray alloc] init];

[individualBinaryArray enumerateObjectsAtIndexes:relevantIndices options:NSEnumerationConcurrent usingBlock:^(id obj, NSUInteger idx, BOOL *stop) {

    NSString *hexString = [self hexString:(NSString *)obj];

    if (hexString.length)
    {
        NSScanner *decimalScanner = [NSScanner scannerWithString:hexString];
        unsigned int decimalValue = 0;

        if ([decimalScanner scanHexInt:&decimalValue])
        {
            // insert value
            // THIS IS THE LINE WHERE THE CRASH OCCURS
            [decimalValues addObject:@(baseValue + incrementValue * decimalValue)];
        }
        else
        {               
            // throw alert/exception etc.   
            *stop = YES;
            indexOfFailure = idx;
        }
    }
    else
    {
        *stop = YES;
        indexOfFailure = idx;
    }       
}];

// Insert list of NSNumbers into CoreData
}

NSMutableArray在块中途获得dealloc

0 个答案: