iphone - 递增 `static int` 会导致 SIGSEGV SEGV_ACCERR

Question

我正在调试报告为的崩溃:

Exception Type:  SIGSEGV
Exception Codes: SEGV_ACCERR

崩溃发生在 numberOfFails++ 的线路上.

该应用程序使用ASIHTTP 。我个人更喜欢使用 NSURLConnection 。我永远不会自动重复 NSURLConnection 的请求如果它失败了，因为我从未见过它在不应该失败的时候失败。我宁愿给 UI 一个刷新按钮或显示 UIAlertView有一个重试按钮或类似的东西。

无论如何，为了与其他团队成员合作，我希望在不替换 ASIHTTP 的情况下解决此问题。与 NSURLConnection现在。

请求以如下内容开始:

- (void)getResources:(CLLocation *)location withQuery:(NSString *)query {
    NSURL *url = [NSURL URLWithString:[NSString stringWithString:@"https://example.com/"]];
    self.resourcesAPIRequest = [ASIFormDataRequest requestWithURL:url];
    [resourcesAPIRequest setPostValue:[Model instance].oauth_token forKey:@"oauth_token"];
    [resourcesAPIRequest setPostValue:[[NSNumber numberWithDouble:location.coordinate.latitude] stringValue] forKey:@"latitude"];
    [resourcesAPIRequest setPostValue:[[NSNumber numberWithDouble:location.coordinate.longitude] stringValue] forKey:@"longitude"];
    [resourcesAPIRequest setPostValue:query forKey:@"query"];
    [resourcesAPIRequest setDelegate:self];
    [resourcesAPIRequest setDidFinishSelector:@selector(resourcesAPIReturned:)];
    resourcesAPIRequest.userInfo = [NSDictionary dictionaryWithObjectsAndKeys:NSStringFromSelector(@selector(getResources:withQuery:)), @"repeatSelector", location, @"argument1", query, @"argument2", nil];   
    [resourcesAPIRequest startAsynchronous];
}

我注意到的一件事是 : <ASIHTTPRequestDelegate>头文件中没有，但是这个回调方法仍然被调用就OK了:

#define maximumNumberOfFails 50

- (void)requestFailed:(ASIFormDataRequest *)request {
    static int numberOfFails = 0;

    if (numberOfFails < maximumNumberOfFails) {
        [NSThread sleepForTimeInterval:sleepTimeInSeconds];
        if ([request.userInfo objectForKey:@"argument2"]) {
            [self performSelector:NSSelectorFromString([request.userInfo objectForKey:@"repeatSelector"]) withObject:[request.userInfo objectForKey:@"argument1"] withObject:[request.userInfo objectForKey:@"argument2"]];
        } else if ([request.userInfo objectForKey:@"argument1"]) {
            [self performSelector:NSSelectorFromString([request.userInfo objectForKey:@"repeatSelector"]) withObject:[request.userInfo objectForKey:@"argument1"]];
        } else {
            [self performSelector:NSSelectorFromString([request.userInfo objectForKey:@"repeatSelector"])];
        }
        numberOfFails++;
    } else {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Problem" message:@"There was a problem connecting to the servers.  Please make sure you have an Internet connection." delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
        [alert show];
        [alert release];
        numberOfFails = 0;
    }
}

另外，我认为 static int numberOfFails应该是static NSUInteger numberOfFails 。而且，我注意到请求以 startAsynchronous 开头。 。是static int numberOfFails原子？这可能就是我们收到错误 SEGV_ACCERR 的原因(映射对象的权限无效)。

想法？

Answer 1

该问题可能与您的静态变量无关。

requestFailed: 是在主线程上执行，还是在后台线程中执行？

如果它在后台线程上，则需要使用performSelectorOnMainThread:withObject:。

如果它在主线程上，您可能需要在执行新的 HTTP 请求之前通过运行循环。为此，请使用 performSelector:withObject:afterDelay:，并传递“0.0”作为延迟。

您会注意到这两种方法都只允许单个方法参数。通常，您在 NSDictionary 中传递参数，而不是像您现在所做的那样尝试事先解析出参数的数量。