iPhone：自定义自动释放池中的崩溃

Posted 2023-03-05

【中文标题】iPhone：自定义自动释放池中的崩溃

【英文标题】：iPhone: Crash in Custom Autorelease Pool

【发布时间】：2010-06-14 14:58:46

【问题描述】：

当我尝试在 HTTP 请求中发布图像时，我的应用程序崩溃了。我正在尝试将图像上传到服务器。崩溃似乎与我的自动释放池有关，因为崩溃被困在[pool release] 消息中。

这是崩溃报告：

#0  0x326712f8 in prepareForMethodLookup ()
#1  0x3266cf5c in lookUpMethod ()
#2  0x32668f28 in objc_msgSend_uncached ()
#3  0x33f70996 in NSPopAutoreleasePool ()
#4  0x33f82a6c in -[NSAutoreleasePool drain] ()
#5  0x00003d3e in -[CameraViewcontroller save:] (self=0x811400, _cmd=0x319c00d4, number=0x11e210) at /Users/hardikrathore/Desktop/LiveVideoRecording/Classes/CameraViewcontroller.m:266
#6  0x33f36f8a in __NSFireDelayedPerform ()
#7  0x32da44c2 in CFRunLoopRunSpecific ()
#8  0x32da3c1e in CFRunLoopRunInMode ()
#9  0x31bb9374 in GSEventRunModal ()
#10 0x30bf3c30 in -[UIApplication _run] ()
#11 0x30bf2230 in UIApplicationMain ()
#12 0x00002650 in main (argc=1, argv=0x2ffff474) at /Users/hardikrathore/Desktop/LiveVideoRecording/main.m:14

崩溃报告说以下代码的最后一行是崩溃点。 （第 266 行）

-(void)save:(id)number

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    j =[number intValue];
    while(screens[j] != NULL)
        NSLog(@" image made : %d",j);
        UIImage * image = [UIImage imageWithCGImage:screens[j]];
        image=[self imageByCropping:image toRect:CGRectMake(0, 0, 320, 240)];
        NSData *imgdata = UIImageJPEGRepresentation(image,0.3);
        [image release];

        CGImageRelease(screens[j]);
        screens[j] = NULL;

        UIImage * image1 = [UIImage imageWithCGImage:screens[j+1]];
        image1=[self imageByCropping:image1 toRect:CGRectMake(0, 0, 320, 240)];
        NSData *imgdata1 = UIImageJPEGRepresentation(image1,0.3);
        [image1 release];

        CGImageRelease(screens[j+1]);
        screens[j+1] = NULL;
        NSString *urlString=@"http://www.test.itmate4.com/iPhoneToServerTwice.php";
        // setting up the request object now
        NSMutableURLRequest *request = [[NSMutableURLRequest alloc]init];
        [request setURL:[NSURL URLWithString:urlString]];
        [request setHTTPMethod:@"POST"];

        NSString *fileName=[VideoID stringByAppendingString:@"_"];
        fileName=[fileName stringByAppendingString:[NSString  stringWithFormat:@"%d",k]];
        NSString *fileName2=[VideoID stringByAppendingString:@"_"];

        fileName2=[fileName2 stringByAppendingString:[NSString  stringWithFormat:@"%d",k+1]];
        /*
         add some header info now
         we always need a boundary when we post a file
         also we need to set the content type

         You might want to generate a random boundary.. this is just the same 
         as my output from wireshark on a valid html post
         */
        NSString *boundary = [NSString stringWithString:@"---------------------------14737809831466499882746641449"];
        NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
        [request addValue:contentType forHTTPHeaderField: @"Content-Type"];

        /*
         now lets create the body of the post
         */
        //NSString *count=[NSString stringWithFormat:@"%d",front];;
        NSMutableData *body = [NSMutableData data];
        [body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];    
        //[body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; count=\"@\"";filename=\"%@.jpg\"\r\n",count,fileName] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; filename=\"%@.jpg\"\r\n",fileName] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[NSData dataWithData:imgdata]];
        [body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
        //second boundary

        NSString *string1 = [[NSString alloc] initWithFormat:@"\r\n--%@\r\n",boundary];
        NSString *string2 =[[NSString alloc] initWithFormat:@"Content-Disposition: form-data; name=\"userfile2\"; filename=\"%@.jpg\"\r\n",fileName2];
        NSString *string3 =[[NSString alloc] initWithFormat:@"\r\n--%@--\r\n",boundary];


        [body appendData:[string1 dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[string2 dataUsingEncoding:NSUTF8StringEncoding]];
        //experiment 
        //[body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile2\"; filename=\"%@.jpg\"\r\n",fileName2] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[NSData dataWithData:imgdata1]];
        //[body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[string3 dataUsingEncoding:NSUTF8StringEncoding]]; 
        // setting the body of the post to the reqeust
        [request setHTTPBody:body];
        // now lets make the connection to the web
        NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
        NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];
        if([returnString isEqualToString:@"SUCCESS"])
        
            NSLog(returnString);
            k=k+2;
            j=j+2;
            [self performSelectorInBackground:@selector(save:) withObject:(id)[NSNumber numberWithInt:j]];
        

        [imgdata release];  
        [imgdata1 release]; 

    [NSThread sleepForTimeInterval:.01];

       
    [pool drain];           //<-------------Line 266

我不明白导致崩溃的原因。

【问题讨论】：

您确实需要通过点击旁边的复选标记来接受一些答案。在一个月的时间里，你问了 8 个问题，但没有接受任何问题。这使人们不太可能花时间找出您的问题，并且会混淆 *** 系统。

请不要在我花了 15 分钟编辑后关闭它。

【参考方案1】：

您在这里不需要自定义自动释放池。除非您一次保存数十张图像（不太可能），否则不需要本地池。

在循环之外创建自动释放池没有多大意义，因为无论如何循环都包含整个方法。如果您确实需要自定义池，则应将其放在循环中，以便每次通过循环时清理内存。

崩溃可能与池没有直接关系，但这只是调试器捕获它的地方。要开始调试，请注释掉自动释放池及其耗尽。这可能会发现崩溃的根源。

作为一个好的经验法则。在您测试代码段并确定它需要一个本地池之前，不要创建本地池。很少需要，只有当您在小范围内创建大量对象时才需要。

【参考方案2】：

根据您的崩溃报告，很难找出崩溃发生的原因。不确定您是否可以使用 NSLog 来获取一些调试信息（至少在您的示例代码中不能）？ NSLog 是一个将消息输出到输出控制台的函数。这是找出崩溃位置的好工具。