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# Description of Changes Host-side changes extracted from #3327 I added AUTO_INC_OVERFLOW even though we don't currently ever return it, in order to future-proof so it's already there when we start emitting it. Prepublish was failing because it was expecting a wasm module unconditionally, so now it takes ?host_type. I tweaked JS deser to accept null/undefined when the unit type or an option type is expected. I switched to bsatn, because the native sats->js translator wasn't matching what js was expecting. I renamed the sys module: my thinking is that `spacetime:` as a scheme will help disambiguate it, and maybe it could also be used for IMC in the future or something? And I believe we had discussed wanting this to be versioned, similar to wasm imports. Trying to get a borrowed str from deserialize_js doesn't work, because v8 strings don't store utf8. # Testing <!-- Describe any testing you've done, and any testing you'd like your reviewers to do, so that you're confident that all the changes work as expected! --> - [x] All this was done in the course of getting an actual typescript module to successfully publish.
SpacetimeDB.Runtime
This project contains the core SpacetimeDB SATS typesystem, attributes for the codegen as well as runtime bindings for SpacetimeDB WebAssembly modules.
The runtime bindings are currently implementing via Wasi.Sdk package, which is a .NET implementation of the WASI standard. This is likely to change in the future.
While not really documented, it allows to build raw WebAssembly modules with custom bindings as well, which is what we're using here. The process is somewhat complicated, but here are the steps:
bindings.cdeclares raw C bindings to the SpacetimeDB FFI imports and marks them with attributes like__attribute__((import_module("spacetime"), import_name("_insert")))that make them WebAssembly imports. (unfortunately, function name duplication is currently unavoidable)bindings.cimplements a bunch of Mono-compatible wrappers that convert between Mono types and raw types expected by the SpacetimeDB FFI and invoke corresponding raw bindings.Runtime.csdeclares corresponding functions with compatible signatures for Mono-compatible wrappers to attach to. It marks them all with[MethodImpl(MethodImplOptions.InternalCall)].bindings.cattaches all those Mono-compatible wrappers to their C# declarations in amono_stdb_attach_bindingsfunction.bindings.cadds FFI-compatible exports that search for a method by assembly name, namespace, class name and a method name in the Mono runtime and invoke it. Those exports are marked with attributes like__attribute__((export_name("__call_reducer__")))so that they're exported from Wasm by the linker.- Finally,
bindings.cimplements no-op shims for all the WASI APIs so that they're linked internally and not attempted to be imported from the runtime itself.
The result is a WebAssembly module FFI-compatible with SpacetimeDB and with no WASI imports, which is what we need.
Regenerating RawModuleDef
To regenenerate the Autogen folder, run:
cargo run -p spacetimedb-codegen --example regen-csharp-moduledef