iphone - 为什么我在网络通信期间会发生随机崩溃 - (CFRelease 中的崩溃)？

我正在处理我的一个项目，该项目处于维护阶段，所以我没有太多的自由来一次更改主要 block ，在处理这个问题时，我在模拟器和设备上都看到了这个随机崩溃而应用程序与服务器同步。流动的存在 登录->上传本地数据到服务器->从服务器下载数据。

我能够调试的唯一一点是我附上的屏幕截图，我无法从中得出很多推论。

网络通信是通过自定义类促进的，如下所示

httpClient.h -------

#define TIMEOUT_SEC     30.0

@protocol HttpClientEventHandler_iPhone
@optional
- (void)requestSucceeded;
- (void)requestFailedNSError*)error;
@end

@class Reachability;
@interface HttpClient_iPhone : NSObject{
    NSURLConnection *connection;
    NSMutableData *recievedData;
    int statusCode; 
    id delegate;
    Reachability* hostReachable;
    BOOL networkChecked;
}
@property (nonatomic, retain) NSMutableString *previousRequest;
@property (readonly) NSMutableData *recievedData; // XX should be (readonly, retain)
@property (readonly) int statusCode;
@property (nonatomic, assign) id delegate;

+ (NSString*)stringEncodedWithBase64NSString*)str;
+ (NSString*) stringOfAuthorizationHeaderWithUsernameNSString*)username passwordNSString*)password;
- (NSMutableURLRequest*)makeRequestNSString*)url;
- (NSMutableURLRequest*)makeRequestNSString*)url usernameNSString*)username passwordNSString*)password;
- (void)prepareWithRequestNSMutableURLRequest*)request;
- (void)requestGETNSString*)url;
- (void)requestPOST:(NSString*)url body:(NSString*)body type:(NSString*)type;
- (void)requestGET:(NSString*)url username:(NSString*)username password:(NSString*)password;
- (void)requestPOST:(NSString*)url username:(NSString*)username password:(NSString*)password body:(NSString*)body type:(NSString*)type;
- (void)requestPOST:(NSString*)url username:(NSString*)username password:(NSString*)password bodydata:(NSData*)body contenttype:(NSString*)type;
- (void)uploadImage:(NSString*)requesturl
           username:(NSString*)username
           password:(NSString*)password
          imagename:(NSString*)imagename 
        contenttype:(NSString*)contenttype
          imagedata:(NSData*)imagedata;

- (void)cancelTransaction;
- (void)reset;
- (BOOL)checkNetworkStatus;
@end

//HttpClient.m ------------

#import "HttpClient_iPhone.h"
#import "Base64.h"
#import "Reachability.h"
#import "SyncLiteral.h"

@implementation HttpClient_iPhone

@synthesize recievedData, statusCode;
@synthesize delegate,previousRequest;

- (id)init {
    if (self = [super init]) {
        [self reset];
        delegate = nil;
        networkChecked = NO;
    }
    return self;
}

- (void)dealloc {
    [connection release];
    [recievedData release];
    [super dealloc];
}

- (void)reset {
    [recievedData release];
    recievedData = [[NSMutableData alloc] init];
    [connection release];
    connection = nil;
    statusCode = 0; 
    networkChecked = NO;
}

+ (NSString*)stringEncodedWithBase64:(NSString*)str {
    static const char *tbl = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    const char *s = [str UTF8String];
    int length = [str length];
    char *tmp = malloc(length * 4 / 3 + 4);

    int i = 0;
    int n = 0;
    char *p = tmp;

    while (i < length) {
        n = s[i++];
        n *= 256;
        if (i < length) n += s[i];
        i++;
        n *= 256;
        if (i < length) n += s[i];
        i++;

        p[0] = tbl[((n & 0x00fc0000) >> 18)];
        p[1] = tbl[((n & 0x0003f000) >> 12)];
        p[2] = tbl[((n & 0x00000fc0) >>  6)];
        p[3] = tbl[((n & 0x0000003f) >>  0)];

        if (i > length) p[3] = '=';
        if (i > length + 1) p[2] = '=';
        p += 4;
    }
    *p = '\0';
    NSString *ret = [NSString stringWithCString:(const char*)tmp encoding: NSUTF8StringEncoding];
    free(tmp);
    return ret;
}

#pragma mark - HTTP Request creating methods

- (NSMutableURLRequest*)makeRequest:(NSString*)url {
    NSString *encodedUrl = (NSString*)CFURLCreateStringByAddingPercentEscapes(
                                                                              NULL, (CFStringRef)url, NULL, NULL, kCFStringEncodingUTF8);
    NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
    [request setURL:[NSURL URLWithString:encodedUrl]];
    [request setCachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData];
    [request setTimeoutInterval:TIMEOUT_SEC];
    [request setHTTPShouldHandleCookies:FALSE];
    [encodedUrl release];
    return request;
}

- (NSMutableURLRequest*)makeRequest:(NSString*)url username:(NSString*)username password:(NSString*)password {
    NSMutableURLRequest *request = [self makeRequest:url];
    [request setValue:[HttpClient_iPhone stringOfAuthorizationHeaderWithUsername:username password:password]
   forHTTPHeaderField"Authorization"];
    return request;
}

+ (NSString*) stringOfAuthorizationHeaderWithUsername:(NSString*)username password:(NSString*)password {
    return [@"Basic " stringByAppendingString:[HttpClient_iPhone stringEncodedWithBase64:
                                               [NSString stringWithFormat"%@:%@", username, password]]];
}

- (void)prepareWithRequest:(NSMutableURLRequest*)request {
    // do nothing (for OAuthHttpClient)
}

#pragma mark -
#pragma mark HTTP Transaction management methods

/* Sending the Http Request for "GET" */
- (void)requestGET:(NSString*)url {

    //Reseting the http client
    [self reset];

    //Checking the internet connection
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelectorselector(requestFailed]){
            [self.delegate performSelectorselector(requestFailed withObject:nil];
        }       
        return;
    }
    //Sending the http requqest
    NSMutableURLRequest *request = [self makeRequest:url];
    [self prepareWithRequest:request];

    if(![[url lastPathComponent] isEqualToString"pda_errorlogs"])
        self.previousRequest = [NSMutableString string];
    [self.previousRequest appendFormat"GET Requested API - %@\n",url];
    [self.previousRequest appendFormat"\n\n\n"];

    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
}

/* Sending the Http Request for "OST" */
- (void)requestPOST:(NSString*)url body:(NSString*)body type:(NSString*)type {

    //Reseting the http client
    [self reset];
    //Checking the internet connection
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelectorselector(requestFailed]){
            [self.delegate performSelectorselector(requestFailed withObject:nil];
        }       
        return;
    }
    //Sending the http requqest
    NSMutableURLRequest *request = [self makeRequest:url];
    [request setHTTPMethod"OST"];
    if (type != nil && ![type isEqualToString:@""])
        [request setValue:type forHTTPHeaderField:@"Content-Type"]; 
    if (body) {
        [request setHTTPBody:[body dataUsingEncoding:NSUTF8StringEncoding]];
    }
    [self prepareWithRequest:request];
    if(![[url lastPathComponent] isEqualToString:@"pda_errorlogs"])
        self.previousRequest = [NSMutableString string];
    [self.previousRequest appendFormat:@"ost Requested API - %@\n",url];
    [self.previousRequest appendFormat:@"ost Data - %@\n",body];
    [self.previousRequest appendFormat:@"\n\n\n"];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

/* Sending the Http Request for "GET" with username and password */
- (void)requestGET:(NSString*)url username:(NSString*)username password:(NSString*)password {
    //Reseting the http client
    [self reset];

    //Checking the internet connection
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed]){
            [self.delegate performSelector:@selector(requestFailed withObject:nil];
        }       
        return;
    }
    //Sending the http requqest
    NSMutableURLRequest *request = [self makeRequest:url username:username password:password];
    if(![[url lastPathComponent] isEqualToString:@"pda_errorlogs"])
        self.previousRequest = [NSMutableString string];
    [self.previousRequest appendFormat:@"ost Requested API - %@\n",url];
    [self.previousRequest appendFormat:@"Authorization user - %@\n",username];
    [self.previousRequest appendFormat:@"Authorizating password - %@\n",password];
    [self.previousRequest appendFormat:@"\n\n\n"];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
}

/* Sending the Http Request for "OST" with username and password */
- (void)requestPOST:(NSString*)url username:(NSString*)username password:(NSString*)password body:(NSString*)body type:(NSString*)type {
    //Reseting the http client
    [self reset];
    //Checking the internet connection
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed]){
            [self.delegate performSelector:@selector(requestFailed withObject:nil];
        }       
        return;
    }
    //Sending the http requqest
    NSMutableURLRequest *request = [self makeRequest:url username:username password:password];
    [request setHTTPMethod:@"OST"];
    if (type != nil && ![type isEqualToString:@""])
        [request setValue:type forHTTPHeaderField:@"Content-Type"]; 
    if (body) {
        [request setHTTPBody:[body dataUsingEncoding:NSUTF8StringEncoding]];
    }
    [self prepareWithRequest:request];
    if(![[url lastPathComponent] isEqualToString:@"pda_errorlogs"])
        self.previousRequest = [NSMutableString string];
    [self.previousRequest appendFormat:@"ost Requested API - %@\n",url];
    [self.previousRequest appendFormat:@"Authorization user - %@\n",username];
    [self.previousRequest appendFormat:@"Authorizating password - %@\n",password];
    [self.previousRequest appendFormat:@"ost Data - %@\n",body];
    [self.previousRequest appendFormat:@"\n\n\n"];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

/* Sending the Http Request for "OST" with username and password */
- (void)requestPOST:(NSString*)url username:(NSString*)username password:(NSString*)password bodydata:(NSData*)body contenttype:(NSString*)type {
    //Reseting the http client
    [self reset];
    //Checking the internet connection
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed]){
            [self.delegate performSelector:@selector(requestFailed withObject:nil];
        }       
        return;
    }
    //Sending the http requqest
    NSMutableURLRequest *request = [self makeRequest:url username:username password:password];
    [request setHTTPMethod:@"POST"];
    if (type != nil && ![type isEqualToString:@""])
        [request setValue:type forHTTPHeaderField:@"Content-Type"]; 
    if (body) {
        [request setHTTPBody:body];
    }
    if (body != nil && [body length] > 0){
        NSString* length_str = [NSString stringWithFormat:@"%d", [body length]];
        [request setValue:length_str forHTTPHeaderField:@"Content-Length"];
    }
    [self prepareWithRequest:request];
    if(![[url lastPathComponent] isEqualToString:@"pda_errorlogs"])
        self.previousRequest = [NSMutableString string];
    [self.previousRequest appendFormat:@"Post Requested API - %@\n",url];
    [self.previousRequest appendFormat:@"Authorization user - %@\n",username];
    [self.previousRequest appendFormat:@"Authorizating password - %@\n",password];
    [self.previousRequest appendFormat:@"Post Data - %@\n",[[[NSString alloc] initWithData:body encoding:NSUTF8StringEncoding]autorelease]];
    [self.previousRequest appendFormat:@"\n\n\n"];

    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

/* Sending the Http Request for uploading the image from database */
- (void)uploadImage:(NSString*)requesturl
           username:(NSString*)username
           password:(NSString*)password
          imagename:(NSString*)imagename 
        contenttype:(NSString*)contenttype
          imagedata:(NSData*)imagedata {

    //Reseting the http client
    [self reset];

    //Checking the internet connection
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed:)]){
            [self.delegate performSelector:@selector(requestFailed:) withObject:nil];
        }       
        return;
    }
    //Sending the http requqest
    NSString *boundary = @"---------------------------14737809831466499882746641449"; 
    NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary]; 
    NSURL *url = [NSURL URLWithString:requesturl];

    NSMutableURLRequest *request = [self makeRequest:requesturl username:username password:password];
    [request addValue:contentType forHTTPHeaderField: @"Content-Type"];

    NSMutableData *postbody = [NSMutableData data]; 
    [postbody appendData:[[NSString stringWithFormat:@"--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]]; 
    [postbody appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"uploadfile\"; filename=\"%@\"\r\n", imagename] dataUsingEncoding:NSUTF8StringEncoding]]; 
    [postbody appendData:[@"Content-Type: application/octet-stream\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]]; 
    NSData* encoded_data = [Base64 encode:imagedata];
    [postbody appendData:[NSData dataWithData:encoded_data]];
    [postbody appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]]; 

    [request setURL:url];
    [request setHTTPMethod:@"POST"];
    [encoded_data release];
    [request setHTTPBody:postbody]; 
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

/* Canceling the HTTP Transaction */
- (void)cancelTransaction {
    [connection cancel];
    [self reset];
}

#pragma mark -
#pragma mark NSURLConnectionDelegate methods

- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse {
    return nil;
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    statusCode = [(NSHTTPURLResponse*)response statusCode];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [recievedData appendData:data];
#ifdef _DEBUG
    NSLog(@"Receieved the http body data : \n%@\n", [[[NSString alloc] initWithData:data 
                                        encoding:NSASCIIStringEncoding] autorelease]);
#endif
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
#ifdef DEBUG
    NSLog(@"Receieved the http body data : \n%@\n", [[[NSString alloc] initWithData:recievedData
                                                                           encoding:NSASCIIStringEncoding] autorelease]);
#endif
    if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestSucceeded)]){
        [self.delegate performSelector:@selector(requestSucceeded) withObject:nil];
    }
    [self reset];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError*) error {
#ifdef _DEBUG   
    NSLog(@"didFailWithError \n %@",[error description]);
#endif
    if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed:)]){
        [self.delegate performSelector:@selector(requestFailed:) withObject:error];
    }   
    [self reset];
}

//check network status chages
- (BOOL)checkNetworkStatus {
    BOOL result = NO;
    Reachability* reachability = [Reachability reachabilityWithHostName:SERVER_ADDRESS];
    NetworkStatus remoteHostStatus = [reachability currentReachabilityStatus];  

    if(remoteHostStatus == NotReachable) { 
#ifdef _DEBUG       
        NSLog(@"\nNetwork Status : not reachable\n");
#endif
        result = NO;
    }else if (remoteHostStatus == ReachableViaWWAN) { 
#ifdef _DEBUG       
        NSLog(@"\nNetwork Status : reachable via wwan\n");
#endif
        result = YES;
    }else if (remoteHostStatus == ReachableViaWiFi) { 
#ifdef _DEBUG
        NSLog(@"\nNetwork Status : reachable via wifi\n");
#endif
        result = YES;       
    }
    return result;
}

@结束

如果有人可以指导我正确的方向，那将有很大帮助。该项目使用 SDK 6.1 和部署目标 4.3。

//编辑我的问题

目前的实现如下

@interface HttpClient_iPhone : NSObject{
    NSURLConnection *connection;
    NSMutableData *recievedData;
    int statusCode; 
    id delegate;
    Reachability* hostReachable;
    BOOL networkChecked;
}

@property (retain,atomic) NSMutableString *previousRequest;
@property (retain,readonly) NSMutableData *recievedData;
@property (readonly) int statusCode;
@property (nonatomic, assign) id delegate;

现在对应的.m是

@implementation HttpClient_iPhone

@synthesize recievedData, statusCode;
@synthesize delegate,previousRequest;

- (id)init {
    if (self = [super init]) {
        [self reset];
        delegate = nil;
        networkChecked = NO;
    }
    return self;
}

- (void)dealloc {
    if (connection) {
        [connection cancel];
    }
    [connection release];
    connection = nil;

    if (recievedData) {
        [recievedData release];
        recievedData = nil;
    }
    [super dealloc];
}

- (void)reset {
    if (recievedData) {
        [recievedData release];
        recievedData = nil;
    }

    recievedData = [[NSMutableData alloc] init];

    if (connection) {
        [connection cancel];
        [connection release];
        connection = nil;
    }
    statusCode = 0;
    networkChecked = NO;
}

- (void)requestGET:(NSString*)url {

    //Reseting the http client
    [self reset];

    //Checking the internet connection
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed:)]){
            [self.delegate performSelector:@selector(requestFailed:) withObject:nil];
        }       
        return;
    }

    NSMutableURLRequest *request = [self makeRequest:url];
    [self prepareWithRequest:request];
    if(![[url lastPathComponent] isEqualToString:@"pda_errorlogs"])
        self.previousRequest = [NSMutableString string];
    [self.previousRequest appendFormat:@"GET Requested API - %@\n",url];
    [self.previousRequest appendFormat:@"\n\n\n"];

    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
}

- (void)requestPOST:(NSString*)url body:(NSString*)body type:(NSString*)type {
    [self reset];
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed:)]){
            [self.delegate performSelector:@selector(requestFailed:) withObject:nil];
        }       
        return;
    }
    NSMutableURLRequest *request = [self makeRequest:url];
    [request setHTTPMethod:@"POST"];
    if (type != nil && ![type isEqualToString:@""])
        [request setValue:type forHTTPHeaderField:@"Content-Type"]; 
    if (body) {
        [request setHTTPBody:[body dataUsingEncoding:NSUTF8StringEncoding]];
    }
    [self prepareWithRequest:request];
    if(![[url lastPathComponent] isEqualToString:@"pda_errorlogs"])
        self.previousRequest = [NSMutableString string];
    [self.previousRequest appendFormat:@"Post Requested API - %@\n",url];
    [self.previousRequest appendFormat:@"Post Data - %@\n",body];
    [self.previousRequest appendFormat:@"\n\n\n"];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

- (void)requestGET:(NSString*)url username:(NSString*)username password:(NSString*)password {
    [self reset];
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed:)]){
            [self.delegate performSelector:@selector(requestFailed:) withObject:nil];
        }       
        return;
    }
    NSMutableURLRequest *request = [self makeRequest:url username:username password:password];
    if(![[url lastPathComponent] isEqualToString:@"pda_errorlogs"])
        self.previousRequest = [NSMutableString string];
    [self.previousRequest appendFormat:@"Post Requested API - %@\n",url];
    [self.previousRequest appendFormat:@"Authorization user - %@\n",username];
    [self.previousRequest appendFormat:@"Authorizating password - %@\n",password];
    [self.previousRequest appendFormat:@"\n\n\n"];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
}

- (void)requestPOST:(NSString*)url username:(NSString*)username password:(NSString*)password body:(NSString*)body type:(NSString*)type {
    [self reset];
    if ([self checkNetworkStatus] == NO){
        if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed:)]){
            [self.delegate performSelector:@selector(requestFailed:) withObject:nil];
        }       
        return;
    }
    NSMutableURLRequest *request = [self makeRequest:url username:username password:password];
    [request setHTTPMethod:@"POST"];
    if (type != nil && ![type isEqualToString:@""])
        [request setValue:type forHTTPHeaderField:@"Content-Type"]; 
    if (body) {
        [request setHTTPBody:[body dataUsingEncoding:NSUTF8StringEncoding]];
    }
    [self prepareWithRequest:request];
    if(![[url lastPathComponent] isEqualToString:@"pda_errorlogs"])
        self.previousRequest = [NSMutableString string];
    [self.previousRequest appendFormat:@"Post Requested API - %@\n",url];
    [self.previousRequest appendFormat:@"Authorization user - %@\n",username];
    [self.previousRequest appendFormat:@"Authorizating password - %@\n",password];
    [self.previousRequest appendFormat:@"Post Data - %@\n",body];
    [self.previousRequest appendFormat:@"\n\n\n"];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

- (void)requestPOST:(NSString*)url username:(NSString*)username password:(NSString*)password bodydata:(NSData*)body contenttype:(NSString*)type {
    [self reset];
}

- (void)cancelTransaction {
    [self reset];
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    statusCode = [(NSHTTPURLResponse*)response statusCode];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [recievedData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestSucceeded)]){
        [self.delegate performSelector:@selector(requestSucceeded) withObject:nil];
    }
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError*) error {
    if (self.delegate != nil && [self.delegate respondsToSelector:@selector(requestFailed:)]){
        [self.delegate performSelector:@selector(requestFailed:) withObject:error];
    }   
}

//Crashlytics 上报告的崩溃日志图像

第 1 部分，共 2 部分

第 2 部分，共 2 部分

---

Best Answer-推荐答案

两条评论:

1) 将 header 中的 recievedData 属性类型更改为“保留”(即使它没有在您的代码中用作属性)

2) 在你释放一个NSURLConnection之前，你应该发送它cancel，即[connection cancel]。你在 dealloc 和 reset 中释放它。另外，首先要取消它 - 不要事先发布可能被它使用的数据。

编辑:根据您当前的代码，您的 reset 方法在修改可变数据之前仍然会取消。我修改了您的代码，如下所示，以反射(reflect)您的 dealloc 方法(您不需要 nil 语句):

- (void)reset {
    if (connection) {
        [connection cancel];
        [connection release];
        connection = nil;
    }
    if (recievedData) {
        [recievedData release];
        recievedData = nil;
    }

    recievedData = [[NSMutableData alloc] init];

    statusCode = 0;
    networkChecked = NO;
}

- (void)dealloc {
    if (connection) {
        [connection cancel];
        [connection release];
    }

    if (recievedData) {
        [recievedData release];
    }
    [super dealloc];
}

试试看。

关于iphone - 为什么我在网络通信期间会发生随机崩溃 - (CFRelease 中的崩溃)？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/16602738/