Implement RFC 11: Redesigning Wasmtime's APIs (#2897)

Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.

examples/wasi/main.c

@@ -28,12 +28,18 @@ to tweak the `-lpthread` and such annotations.
 static void exit_with_error(const char *message, wasmtime_error_t *error, wasm_trap_t *trap);
 
 int main() {
-  int ret = 0;
   // Set up our context
   wasm_engine_t *engine = wasm_engine_new();
   assert(engine != NULL);
-  wasm_store_t *store = wasm_store_new(engine);
+  wasmtime_store_t *store = wasmtime_store_new(engine, NULL, NULL);
   assert(store != NULL);
+  wasmtime_context_t *context = wasmtime_store_context(store);
+
+  // Create a linker with WASI functions defined
+  wasmtime_linker_t *linker = wasmtime_linker_new(engine);
+  wasmtime_error_t *error = wasmtime_linker_define_wasi(linker);
+  if (error != NULL)
+    exit_with_error("failed to link wasi", error, NULL);
 
   wasm_byte_vec_t wasm;
   // Load our input file to parse it next
@@ -53,8 +59,8 @@ int main() {
   fclose(file);
 
   // Compile our modules
-  wasm_module_t *module = NULL;
-  wasmtime_error_t *error = wasmtime_module_new(engine, &wasm, &module);
+  wasmtime_module_t *module = NULL;
+  error = wasmtime_module_new(engine, (uint8_t*)wasm.data, wasm.size, &module);
   if (!module)
     exit_with_error("failed to compile module", error, NULL);
   wasm_byte_vec_delete(&wasm);
@@ -68,39 +74,28 @@ int main() {
   wasi_config_inherit_stdout(wasi_config);
   wasi_config_inherit_stderr(wasi_config);
   wasm_trap_t *trap = NULL;
-  wasi_instance_t *wasi = wasi_instance_new(store, "wasi_snapshot_preview1", wasi_config, &trap);
-  if (wasi == NULL)
-    exit_with_error("failed to instantiate WASI", NULL, trap);
-
-  wasmtime_linker_t *linker = wasmtime_linker_new(store);
-  error = wasmtime_linker_define_wasi(linker, wasi);
+  error = wasmtime_context_set_wasi(context, wasi_config);
   if (error != NULL)
-    exit_with_error("failed to link wasi", error, NULL);
+    exit_with_error("failed to instantiate WASI", error, NULL);
 
   // Instantiate the module
-  wasm_name_t empty;
-  wasm_name_new_from_string(&empty, "");
-  wasm_instance_t *instance = NULL;
-  error = wasmtime_linker_module(linker, &empty, module);
+  error = wasmtime_linker_module(linker, context, "", 0, module);
   if (error != NULL)
     exit_with_error("failed to instantiate module", error, NULL);
 
   // Run it.
-  wasm_func_t* func;
-  wasmtime_linker_get_default(linker, &empty, &func);
+  wasmtime_func_t func;
+  error = wasmtime_linker_get_default(linker, context, "", 0, &func);
   if (error != NULL)
     exit_with_error("failed to locate default export for module", error, NULL);
 
-  wasm_val_vec_t args_vec = WASM_EMPTY_VEC;
-  wasm_val_vec_t results_vec = WASM_EMPTY_VEC;
-  error = wasmtime_func_call(func, &args_vec, &results_vec, &trap);
-  if (error != NULL)
+  error = wasmtime_func_call(context, &func, NULL, 0, NULL, 0, &trap);
+  if (error != NULL || trap != NULL)
     exit_with_error("error calling default export", error, trap);
 
   // Clean up after ourselves at this point
-  wasm_name_delete(&empty);
-  wasm_module_delete(module);
-  wasm_store_delete(store);
+  wasmtime_module_delete(module);
+  wasmtime_store_delete(store);
   wasm_engine_delete(engine);
   return 0;
 }

examples/wasi/main.rs

@@ -5,38 +5,30 @@
 
 use anyhow::Result;
 use wasmtime::*;
-use wasmtime_wasi::sync::{Wasi, WasiCtxBuilder};
+use wasmtime_wasi::sync::WasiCtxBuilder;
 
 fn main() -> Result<()> {
-    tracing_subscriber::FmtSubscriber::builder()
-        .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
-        .with_ansi(true)
-        .init();
-
     // Define the WASI functions globally on the `Config`.
-    let mut config = Config::default();
-    Wasi::add_to_config(&mut config);
+    let engine = Engine::default();
+    let mut linker = Linker::new(&engine);
+    wasmtime_wasi::add_to_linker(&mut linker, |s| s)?;
 
-    let store = Store::new(&Engine::new(&config)?);
-
-    // Set the WASI context in the store; all instances in the store share this context.
-    // `WasiCtxBuilder` provides a number of ways to configure what the target program
-    // will have access to.
-    assert!(Wasi::set_context(
-        &store,
-        WasiCtxBuilder::new()
-            .inherit_stdio()
-            .inherit_args()?
-            .build()
-    )
-    .is_ok());
-
-    let mut linker = Linker::new(&store);
+    // Create a WASI context and put it in a Store; all instances in the store
+    // share this context. `WasiCtxBuilder` provides a number of ways to
+    // configure what the target program will have access to.
+    let wasi = WasiCtxBuilder::new()
+        .inherit_stdio()
+        .inherit_args()?
+        .build();
+    let mut store = Store::new(&engine, wasi);
 
     // Instantiate our module with the imports we've created, and run it.
-    let module = Module::from_file(store.engine(), "target/wasm32-wasi/debug/wasi.wasm")?;
-    linker.module("", &module)?;
-    linker.get_default("")?.typed::<(), ()>()?.call(())?;
+    let module = Module::from_file(&engine, "target/wasm32-wasi/debug/wasi.wasm")?;
+    linker.module(&mut store, "", &module)?;
+    linker
+        .get_default(&mut store, "")?
+        .typed::<(), (), _>(&store)?
+        .call(&mut store, ())?;
 
     Ok(())
 }