❄️ Sane C++ January 25

SC::Async

SC::Async has been the main focus of the month.

Simplification:

• Remove one state throughout the system (Teardown)

Consistency:

• Expose callback to signal when a request is fully stopped after issuing a AsyncRequest::stop().

Features:

• Exclude specific request from active count (it will not keep the loop alive)
• Enumerate all (non-internal) active and submitted async requests
• Interrupt event loop even with active requests
• Update loop time externally
• Check request state (free / active / cancelling)

Stability:

• Fix issues with AsyncWakeUp on io_uring

Timers (AsyncLoopTimeout) improvements:

• Invoke timers consistently when one of them is being cancelled during another timer's callback.
• Sort timers by expiration time (first) and insertion order (second)
• Use Monotonic clock everywhere
• Unify code on all backends (including io_uring)

Detailed List of commits:

• Async: Add a callback to signal when AsyncRequest is fully closed after stop()
• Async: Add method to check if event loop is initialized
• Async: Add method to enumerate all requests of the event loop
• Async: Add methods to check if a request is free/active/cancelling and update loop time
• Async: Allow excluding a specific request from active count
• Async: Allow interrupting event loop even with active requests
• Async: Do not enumerate internally created requests
• Async: Enforce temporal ordering of loop timeouts
• Async: Expose callback to notify before and after polling for IO
• Async: Fix AsyncWakeUp on io_uring
• Async: Fix expired timers invocation when they're being cancelled
• Async: Make teardownAsync static function
• Async: Reduce AsyncEventLoop size
• Async: Remove Teardown state to reduce complexity
• Async: Split AsyncTest in multiple files for easier navigation
• Async: Update time in any case after a kernel sync operation
• Async: Use Monotonic clock everywhere
• Async: When interrupted loop shouldn't dispatch completions

SC::AsyncStreams

Some minimal work as been done to the SC::AsyncStreams library as well.

One video has been recorded Showing how to move the transform stream compression operation on a background thread, using AsyncLoopWork. This video pauses (for now) the series of videos dedicated to SC::AsyncStreams.

Detailed List of commits:

• AsyncStreams: Compress on separate thread on zlib transform stream
• AsyncStreams: Fix zlib api calling convention

SC::Foundation

SC::Foundation most notable change has been using a different approach in SC::Function.

We're now using a vtable-like approach that allows saving one entire pointer (!!) for each SC::Function instance.

The price to pay is the static initialization (that will require a mutex acquisition) and one more indirection, but it has been considered a good tradeoff.

Detailed List of commits:

• Foundation: Add a basic test for HeapBuffer
• Foundation: Add explicit size for Linux on OpaqueObject
• Foundation: Use static vtable approach in Function to reduce its size

SC::Time

The SC::Time library got user defined literals, some conversion between different units and differentiation between monotonic and realtime clocks.

A nasty bug regarding time normalization in SC::Time::HighResolutionCounter has been fixed too!

Detailed List of commits:

• Time: Add User defined literals and more conversions between types
• Time: Differentiate between Monotonic and Realtime clocks
• Time: Handle time normalization in HighResolutionCounter

Minor changes

And these are some minor changes that don't have enough impact to deserve a dedicated comment.

Detailed List of commits:

• Everywhere: Fix build and runtime issues with GCC 13
• Plugin: Use correct casing for the "nologo" option
• SCExample: Stop timer during close
• SCExample: Update dear-imgui and sokol