Partial implementation, gaps and impossibilities noted internally as TODO comments.
* CPProgress.j: Introduce CPProgress, modelled on NSProgress.
- Count units of work, with fraction completed, finished and indeterminate states.
- Compose progress trees through explicit children and the current progress object.
- Cancel, pause and resume, with handlers, propagating to children.
- Announce unit-count changes through key-value observing across the tree.
* CPError.j: Add CPUserCancelledError.
* CPItemProvider.j:
- Return a CPProgress from each load, counting bytes read for files and aborting the read on cancellation.
- Pass file contents to CPData as a binary string rather than a byte array.
- Implement -canLoadObjectOfClass: and -loadObjectOfClass:completionHandler:.
- Add the CPString (CPItemProvider) reading category.
* CPString+Encoding.j: Decode data held as a binary string through a Uint8Array, without building a byte array.
* Foundation.j: Import CPProgress.j.
* CPProgressTest.j: Add unit tests covering counts, children, the current progress object, cancellation, pausing, observation and user information.
* CPItemProviderTest.j: Add unit tests covering read progress, cancellation, completion and string loading.
David Richardson
021e9935aa