Inspired by Friday Q&A 2013-05-03: Proper Use of Asserts I made these macros to handle my assertions.
Be Aware: I don't disable the asserts in release code. I agree with Mike Ash that if something is wrong it should break ASAP.
Inspired by Krzysztof Zabłocki blog post, macros of the family FCYAssertOrReturn does not
crash the app in release builds only in debug. Why this? An app shouldn't crash because of an external change.
Important Note: FCYAssertOrReturn uses NS_BLOCK_ASSERTIONS just like NSAssert.
FCYAssert, if you have control over the caller code;FCYAssertOrReturn, if you are asserting external code, for example, if a JSON root element is a NSDictionary.
In your Podfile add this line:
pod 'FCYAsserts'
Just add the files in FCYAsserts and import FCYAsserts.h in your prefix
header (*.pch) or directly in each .m you want.
The usage is exactly like NSAssert the difference is that the log is more complete.
// AppDelegate.m
#import "FCYAsserts.h"
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
[self startLengthyOperation];
// ...
}
- (void)startLengthyOperation {
FCYAssertIsNotInMainThread;
// ...
}
Would abort with the following log using, by default, NSLog:
-[TPAppDelegate startLengthyOperation]: Assertion '(![NSThread isMainThread])' failed on line /Users/you/dev/Project/AppDelegate.m:56. This should not be running on the main thread.
NSError *error;
id json = [NSJSONSerialization JSONObjectWithData:dataFromServer options:0 error:&error];
if (error) {
completionBlock(nil, error);
} else {
FCYAssertOrReturnBlock([json isKindOfClass:[NSDictionary class]], @"Invalid Server Data", ^(NSError *assertError){
completionBlock(nil, assertError);
});
completionBlock(json, nil);
}
If json is not a NSDictionary in debug code it would abort and log and in release it would just log:
-[MyClass callServiceWithCompletionBlock:]: Assertion '[json isKindOfClass:[NSDictionary class]]' failed on line /Users/you/dev/Project/MyClass.m:42. Invalid Server Data
If you use CocoaLumberjack you can make FCYAsserts use it by defining
FCYAssertLog:
#import "FCYAsserts.h"
#define FCYAssertLog DDLogError
With CocoaLumberjack you can save your logs into a file, and much more. Which is very useful to support request, you could attach the logs when the user send a support request from within your app.
And it is faster than NSLog.
Enjoy!
(The MIT License)
Copyright © 2013 Felipe Cypriano
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