[−][src]Macro wasmtime_wiggle::wasmtime_integration

wasmtime_integration!() { /* proc-macro */ }

Define the structs required to integrate a Wiggle implementation with Wasmtime.

Arguments

Arguments are provided using struct syntax e.g. { arg_name: value }.

  • target: The path of the module where the Wiggle implementation is defined.
  • witx or witx_literal: the .witx document where the interface is defined. witx takes a list of filesystem paths, e.g. ["/path/to/file1.witx", "./path/to_file2.witx"]. Relative paths are relative to the root of the crate where the macro is invoked. witx_literal takes a string of the witx document, e.g. "(typename $foo u8)".
  • ctx: The context struct used for the Wiggle implementation. This must be the same type as the wasmtime_wiggle::from_witx macro at target was invoked with. However, it must be imported to the current scope so that it is a bare identifier e.g. CtxType, not path::to::CtxType.
  • modules: Describes how any modules in the witx document will be implemented as Wasmtime instances. modules takes a map from the witx module name to a configuration struct, e.g. foo => { name: Foo }, bar => { name: Bar } will generate integrations for the modules named foo and bar in the witx document, as pub struct Foo and pub struct Bar respectively. The module configuration uses struct syntax with the following fields:
    • name: required, gives the name of the struct which encapsulates the instance for Wasmtime.
    • docs: optional, a doc string that will be used for the definition of the struct.
    • function_override: A map of witx function names to Rust function symbols for functions that should not call the Wiggle-generated functions, but instead use a separate implementation. This is typically used for functions that need to interact with Wasmtime in a manner that Wiggle does not permit, e.g. wasi's proc_exit function needs to return a Trap directly to the runtime. Example: modules: { some_module => { name: SomeTypeName, docs: "Doc string for definition of SomeTypeName here", function_override: { foo => my_own_foo } }.
  • missing_memory: Describes the error value to return in case the calling module does not export a Memory as "memory". This value is given in braces, e.g. missing_memory: { wasi_common::wasi::Errno::Inval }.