This is a companion project with code for the corresponding blog post.
The original code based on Kotlin Conf 2018 talk "Kotlin Coroutines in Practice" (video, slides).
See the following sources:
| Source | Description | Playground |
|---|---|---|
| DownloaderOriginal.kt | The original version from presentation that suffers from deadlock. | playground |
| Downloader.go | Go version of the same code. | playground |
| DownloaderWithMailbox.kt | Does not use select, but actor patter instead. Still deadlocks. |
playground |
| DownloaderWithBuffer.kt | Same as original but with buffers for both locations and contents channels. Still deadlocks. |
playground |
| DownloaderWithUnlimitedBuffer.kt | Uses unlimited buffer for contents channel and seems to work. |
playground |
| DownloaderWithPriority.kt | Gives contents channel priority over references in downloader coroutine. Still deadlocks. |
playground |
| DownloaderFixedPriority.kt | Fixes the problem by adjusting priority of select in downloader (contents first) and using a buffer for contents channels. |
playground |
| DownloaderFixedSelect.kt | Fixes the problem by performing locations.send inside select in downloader. |
playground |
There is a formal model-checker that takes a simple description of the corresponding
communicating final-state machines and exhaustively checks all system states for the presence of deadlocks.
It's code is in CFSMVerifier.kt file and there are configuration files for
all examples in its directory. The verifier supports plain CFSM using rendezvous channels,
has built in capability to represent buffered channels with an addition process, and supports priorities
for Kotlin-style select expression using addition "transitional" states.
To use it, run CFSMVerifier with path(s) to the corresponding .cfsm configuration files.