core_model
Three primitives that a Dart application keeps re-deriving, extracted once and tested. No Flutter
dependency: it runs under dart test, in an isolate, or in a CLI.
Lease: monotonic ownership over a shared resource
One lease guards one resource scope: a hardware session, a storage key, a composition of
dependencies. An owner calls acquire() and keeps the handle; a new term invalidates every handle
issued before it, so a stale owner's deferred work (a queued release, a late callback, a retry)
becomes a no-op instead of tearing down the current owner's state.
final lease = Lease();
final handle = lease.acquire();
// ... later, on a path that may have been superseded:
lease.guard(handle, () => transport.close());
It is not a mutex: it serializes nothing, it decides whose completed work still counts.
CancelToken: cooperative cancellation
A token an operation checks, and a caller cancels. No timers, no zones, no Future wrapping.
retryBackoff: exponential backoff with jitter
The retry schedule as a function, so a client's retry policy is a value that can be tested rather than a loop that has to be read.
Also here
Guid, a UUID as a string with GuidX.nil and GuidX.empty; IDeviceInfo, the interface an
application implements to describe the device and build it runs on; and a platform-neutral
VoidCallback typedef, so a package that uses it stays free of dart:ui; RetryNotifier, the callback a
retrying middleware reports each attempt through.
Install
dependencies:
core_model:
git:
url: https://github.com/zs-dima/core_model.git
ref: v0.1.0