multitasking 4.2.0

Cooperative multitasking using asynchronous tasks and synchronization primitives, with the ability to safely cancel groups of nested tasks performing I/O wait or listen operations.

Changelog

4.2.0

• Added method cancelAfter() to CancellationTokenSource class.
• The operating algorithm of the TaskCompletionSource has been improved.

4.1.0

• Changed example example_task_wait_in_different_ways.dart.
• Added example example_task_stream.dart.
• Added method whenEach() to Task class.
• Added method delay() to Task class.
• Breaking change: Code normalization, the cancelled identifiers have been renamed to canceled.
• Breaking change: Code normalization, the cancellable identifiers have been renamed to cancelable.

4.0.0

• Breaking change: Code cleanup, removed the following functions: runAndDetach(), runCancellable().
• Breaking change: Code cleanup, removed the classes: CancellableStreamIterator.
• Breaking change: Code normalization, renamed TaskCanceledError class to TaskCanceledException. Also, this class now implements the Exception interface and no longer extends the Error class.
• Non-breaking change: The following methods now return Future<void> instead of void: Task.start(), PauseToken.pause(), PauseToken.resume().

3.8.0

• Added method whenAny() to Task class.
• Added method whenAll() to Task class.
• Changed signature of waitAll() method of Task class to Future<void> waitAll<T>(List<Task<T>> tasks, {Progress<({int count, int total})>? progress}). Now, when specifying a progress parameter it is possible to track the progress of the wait operation.
• Added class CountdownTimer

3.7.0

• Changed signature of wait() method of PauseToken class to Future<void> wait({CancellationToken? token}). Now, when specifying a token parameter, the method can throw a TaskCanceledError exception.

3.6.0

• Added method reacquire() to Lock class. This method is implemented exclusively to ensure fair operation of reacquiring the lock in condition variable in the wait() method.
• Fixed a bug in ManualResetEvent.

3.5.0

• Added method runCancellable() to CancellationToken class. The runCancellable() function now forwards execution to this method.
• Added PauseToken class
• Added Throughput class

3.4.0

• Changed example example_task_cancel_long_network.dart.
• Changed example example_task_cancel_network.dart.
• Changed example example_task_cancel_during_stream_iteration.dart.
• Added class Progress
• Changed example example_task_download_file.dart.

3.3.0

• Non-breaking changes: Handlers of the CancellationToken class can be asynchronous and now they are executed in the zone where the handlers were created via the scheduleMicrotask() call.
• Fixed a bug in AutoResetEvent and ManualResetEvent.

3.2.0

• Added example example_task_wait_in_different_ways.dart.
• Added class ZoneStats
• Added example example_task_zone_stats.dart.

3.1.0

• Breaking change: Removed method runGuarded from class CancellationToken.
• Added function runCancellable() to lib/src/task/cancellation.dart.
• Added function runAndDetach() to lib/src/task/cancellation.dart.

3.0.0

• Breaking change: The task immediately propagates an exception if it is an unhandled exception in the task zone. An unhandled exception in the task zone is considered to be an exception that occurs in the task zone after a task has completed.
• Added method runGuarded() to class CancellationToken. Purpose: Perform asynchronous actions (especially when using I/O operations) with guaranteed protection from unhandled exceptions and "automatic" processing of task cancellation requests.
• Added getter result to class Task.
• Added example example_task_handle_unhandled_error.dart.
• Added example example_task_result.dart.

2.11.0

The ConditionVariable.wait() implementation has been adjusted to make the implementation more consistent with the Moore monitor.

2.10.0

• Breaking change: The ForEach class has been removed in favor of a more correct way to achieve the same result - by using the SteamIterator class.
• Added class AutoResetEvent.
• Added class ManualResetEvent.
• Added example example_task_cancel_isolate.dart.
• Added class CancellableStreamIterator.

2.9.0

• Added class MultipleWriteSingleReadObject.
• Added example example_multiple_write_single_read_object.dart.
• Fixed typo in README.md

2.8.0

• Changed the link to the image mutex.gif.
• Removed unused code from the Lock class.
• The algorithm for the ConditionVariable.tryWait() method has been corrected.

2.7.0

• Fixed a bug with incorrect use of WaitQueue.
• Fixed a bug in ConditionVariable.
• Added image assets/images/mutex.gif.

2.6.0

• Slightly improved ReentrantLock performance.
• The internal algorithm for processing the Task result has been slightly changed.
• Added getters for the Task, for each task state (eg. isCompleted for the TaskState.completed state).
• Breaking change: The Synchronizer class has been renamed to Lock.

2.5.0

• Slightly improved BinarySemaphore performance.
• Slightly improved ReentrantLock performance.
• Changed example example_task_cancel_long_network.dart.
• Changed example example_task_cancel_network.dart.
• Changed example example_task_cancel_await_for_stream_emulation.dart.
• Breaking change: Removed Task.awaitFor method.
• Added class ForEach.

2.4.0

• Breaking change: Removed type parameter from ReentrantLock class.

2.3.0

• Added table of contents in file README.md.
• Added class ReentrantLock.
• Added example example_reentrant_lock.dart.

2.2.0

• Added an explanation of the operating principle and internal structure of the task.
• Changed package description.
• A unified mechanism for implementing a waiting queue has been added (WaitQueue).
• Breaking change:The signatures of some synchronization primitives have been changed to consistently use wait queues. This applies to methods that implement waiting with a timeout (tryWait()).

2.1.0

• Added example example_counting_semaphore.dart.
• Added example example_task_cancel_await_for_stream.dart.
• Added method static Task<void> awaitFor<R>(Stream<R> stream, CancellationToken token, bool Function(R) f).
• Added class CountingSemaphore.
• Added class: BinarySemaphore.
• Breaking change: The functionality of the CancellationToken handler has been changed. Performance and usability have been improved, and most importantly, the restriction on linking to a single task has been lifted.
• Added example example_task_cancel_during_sleep.dart.
• Added example example_binary_semaphore.dart.
• Added class Synchronizer.
• Added class ConditionVariable.
• Added example example_condition_variable.dart.

2.0.0

• Breaking change: Removed support for unsafe task termination.
• Added support for safe task cancellation.

1.2.0

• Minor corrections have been made to the examples.

1.1.0

• Fixed a bug that did not take into account that in Dart, a function cannot return a Future<Future<T>> result. Dart automatically flattens this value to Future<T>.
• Changed signature of the following methods in the Task class: Future<Task<T>> run(), Future<void> start() to Task<T> run(), void start(). First method (run) was changed because Dart blocks Future<Task<T>> Task<T>.run) until the task completes, the second method (start) was changed to be consistent with the first.

1.0.0

• Initial release.