wasmtime-wasi: support both snapshots

crates/wasi/src/lib.rs

@@ -3,9 +3,12 @@ pub use wasi_common::{
     WasiCtx, WasiCtxBuilder, WasiDir, WasiFile,
 };
 
-// Defines a `struct Wasi` with member fields and appropriate APIs for dealing
+pub mod snapshots {
-// with all the various WASI exports.
+    pub mod preview_1 {
-wasmtime_wiggle::wasmtime_integration!({
+        use wasi_common::WasiCtx;
+        // Defines a `struct Wasi` with member fields and appropriate APIs for dealing
+        // with all the various WASI exports.
+        wasmtime_wiggle::wasmtime_integration!({
             // The wiggle code to integrate with lives here:
             target: wasi_common::snapshots::preview_1,
             // This must be the same witx document as used above. This should be ensured by
@@ -26,4 +29,33 @@ necessary. Additionally [`Wasi::get_export`] can be used to do name-based
 resolution.",
                 },
             },
-});
+        });
+    }
+    pub mod preview_0 {
+        use wasi_common::WasiCtx;
+        // Defines a `struct Wasi` with member fields and appropriate APIs for dealing
+        // with all the various WASI exports.
+        wasmtime_wiggle::wasmtime_integration!({
+            // The wiggle code to integrate with lives here:
+            target: wasi_common::snapshots::preview_0,
+            // This must be the same witx document as used above. This should be ensured by
+            // the `WASI_ROOT` env variable, which is set in wasi-common's `build.rs`.
+            witx: ["$WASI_ROOT/phases/old/snapshot_0/witx/wasi_unstable.witx"],
+            // This must be the same ctx type as used for the target:
+            ctx: WasiCtx,
+            // This macro will emit a struct to represent the instance,
+            // with this name and docs:
+            modules: { wasi_unstable =>
+                { name: Wasi,
+                  docs: "An instantiated instance of the wasi exports.
+
+This represents a wasi module which can be used to instantiate other wasm
+modules. This structure exports all that various fields of the wasi instance
+as fields which can be used to implement your own instantiation logic, if
+necessary. Additionally [`Wasi::get_export`] can be used to do name-based
+resolution.",
+                },
+            },
+        });
+    }
+}