Memory management with blocks - leak
I use blocks to perform an access check in a service class, but it is leaking memory. Can someone point out what the problem with my method is? The problem is probably related to which variables I am using within the blocks. I am accessing instance variables, method variables and referencing super.
-(RequestDO*)requestWithURL:(NSString*)url andDelegate:(id<RequestDelegate>)delegate_ signURL:(BOOL)sign_ request:(RequestDO*)request_ postData:(NSString*) postData_ {
if([self requiresUpdatedAccess]){
if(accessRequest == nil){
开发者_JS百科 accessRequest = [[UpdatedAccessManager getPaymentStatus:self] retain];
if(accessRequest.processStatus == kRequestComplete){ // Access check is complete (cached)
[accessRequest release], accessRequest = nil;
return [super requestWithURL:url andDelegate: delegate_ signURL:sign_ request:request_ postData: postData_]; // Do original service request
}
else{
Block_release(completionBlock_);
// When access check is done, we will perform this block to process the original request
completionBlock_ = Block_copy(^(){
/*
url - an instance variable
delegate_, sign_, request_ and postData_ is method scoped variables
*/
NSString *updatedUrl = [Service updateUrlWithUserData: url];
[super requestWithURL:updatedUrl andDelegate: delegate_ signURL:sign_ request:request_ postData: postData_];
});
Block_release(failureBlock_);
// If access check fails, we will perform this block to inform about the error
failureBlock_ = Block_copy(^(RequestDO* req_, NSError* err_){
[delegate_ requestFailed:self.request withError: err_];
});
}
}
}
else{
return [super requestWithURL:url andDelegate: delegate_ signURL:sign_ request:request_ postData: postData_]; // This service does not need access check
}
return accessRequest;
}
In dealloc i have Block_release for both blocks.
The block will retain all used vars. In your case the retain count of your object will be 2 due to the use of it in the block. Thus dealloc is not called and you have a classic retain cycle. To work around this declare
__block id blockSelf = self;
before the block and use blockSelf instead of self in your block.
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