EBPrimitives is a framework that includes various generally-useful primitive classes, described below.
EBConcurrentQueue is a lightweight operation queue implementation that supports both concurrency limits and queue priorities. EBConcurrentQueue is implemented as a thin layer atop plain libdispatch queues, eliminating much of the overhead of NSOperationQueue.
EBConditionLock is a locking primitive (similar to NSConditionLock) that allows clients to lock on any one of multiple conditions, specified using a bit field. An EBConditionLock is always in a single condition -- that is, its condition property is always an integer with exactly one bit set.
An EBConditionLock's condition is set upon initialization via -initWithCondition: (its designated initializer), and when unlocking the lock via -unlockWithCondition:.
EBConditionLock is locked by supplying one or more conditions to -lockOnConditions:. When more than one condition is supplied, they're combined using a bitwise-OR operation. Calling -lockOnConditions: with a value of 0 would result in a deadlock (since no conditions are specified), and therefore raises an exception.
EBDiskCache is a thread-safe, key-value cache implementation that stores and retrieves data to and from disk. Some noteworthy features of EBDiskCache include:
- supports reading and writing data simultaneously from multiple threads
- deletes data from disk when the adjustable size limit is reached
- allows clients to use their own file-reading APIs via the
-startAccessForKey:method, which returns the URL at which data is stored on disk - allows clients to safely delete the entire cache from disk
An EBDiskCache instance is created via its designated initializer -initWithStoreURL:sizeLimit:, where the on-disk URL for the cache is supplied, along with a maximum size to which the cache is allowed to grow until data is evicted. (The current data-eviction algorithm assumes that entries in the cache are of similar size; if a wide variation exists between the sizes of cache entries, the cache will grow beyond the limit in proportion to the variation. The size limit should therefore be considered a guideline rather than a hard limit.)
EBDiskCache can be destroyed (with all files being removed from disk) via the -destroy method. This method safely deletes the cache from disk once there are no outstanding clients reading the cache via -startAccessForKey:. Once the cache has been destroyed, -dataForKey: and -startAccessForKey: return nil for all keys, and other methods (such as -setData:forKey: and -sync) do nothing.
EBReadWriteLock is a simple Objective-C read-write lock, wrapping pthread's rwlock implementation.
EBUseTracker is an Objective-C least-recently-used (LRU) and most-recently-used (MRU) implementation that supports both forward and reverse enumeration.
- Mac OS 10.8 or iOS 6. (Earlier platforms have not been tested.)
- Integrate EBFoundation into your project.
- Drag EBPrimitives.xcodeproj into your project's file hierarchy.
- In your target's "Build Phases" tab:
- Add EBPrimitives as a dependency ("Target Dependencies" section)
- Link against libEBPrimitives.a ("Link Binary With Libraries" section)
- Add
#import <EBPrimitives/EBPrimitives.h>to your source files.
EBPrimitives was created for Lasso.
EBPrimitives is available under the MIT license; see the LICENSE file for more information.