feat: update main code to call itk-wasm code

We call stdout-stderr-test.wasi.wasm's unnamed function.

Author: ctrueden

packages/core/java/src/main/java/org/itk/wasm/Main.java

@@ -19,66 +19,55 @@
  */
 package org.itk.wasm;
 
-import io.github.kawamuray.wasmtime.Engine;
 import io.github.kawamuray.wasmtime.Extern;
 import io.github.kawamuray.wasmtime.Func;
 import io.github.kawamuray.wasmtime.Instance;
+import io.github.kawamuray.wasmtime.Linker;
+import io.github.kawamuray.wasmtime.Memory;
 import io.github.kawamuray.wasmtime.Module;
 import io.github.kawamuray.wasmtime.Store;
 import io.github.kawamuray.wasmtime.WasmFunctions;
+import io.github.kawamuray.wasmtime.WasmFunctions.Consumer0;
+import io.github.kawamuray.wasmtime.wasi.WasiCtx;
+import io.github.kawamuray.wasmtime.wasi.WasiCtxBuilder;
 
 import java.io.ByteArrayOutputStream;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Optional;
 
 public class Main {
   public static void main(String... args) throws IOException {
     // Configure the initial compilation environment, creating the global
     // `Store` structure. Note that you can also tweak configuration settings
     // with a `Config` and an `Engine` if desired.
     System.err.println("Initializing...");
-    try (Store<Void> store = Store.withoutData()) {
-      // Compile the wasm binary into an in-memory instance of a `Module`.
-      System.err.println("Compiling module...");
-      try (Engine engine = store.engine();
-          Module module = new Module(engine, readWAT("hello.wat")))
-      {
-        // Here we handle the imports of the module, which in this case is our
-        // `HelloCallback` type and its associated implementation of `Callback.
-        System.err.println("Creating callback...");
-        try (Func helloFunc = WasmFunctions.wrap(store, () -> {
-          System.err.println("CB!! Calling back...");
-          System.err.println("CB!! > Hello World!");
-        })) {
-          // Once we've got that all set up we can then move to the instantiation
-          // phase, pairing together a compiled module as well as a set of imports.
-          // Note that this is where the wasm `start` function, if any, would run.
-          System.err.println("Instantiating module...");
-          Collection<Extern> imports = Arrays.asList(Extern.fromFunc(helloFunc));
-          try (Instance instance = new Instance(store, module, imports)) {
-            // Next we poke around a bit to extract the `run` function from the module.
-            System.err.println("Extracting export...");
-            try (Func f = instance.getFunc(store, "run").get()) {
-              WasmFunctions.Consumer0 fn = WasmFunctions.consumer(store, f);
+    try (
+        WasiCtx wasi = new WasiCtxBuilder().inheritStdout().inheritStderr().build();
+        Store<Void> store = Store.withoutData(wasi);
+        Linker linker = new Linker(store.engine());
+        Module module = Module.fromBinary(store.engine(), readBytes("../python/itkwasm/test/input/stdout-stderr-test.wasi.wasm")))
+    {
+      // Here we handle the imports of the module, which in this case is our
+      // `HelloCallback` type and its associated implementation of `Callback.
+      System.err.println("Creating callback...");
 
-              // And last but not least we can call it!
-              System.err.println("Calling export...");
-              fn.accept();
-
-              System.err.println("Done.");
-            }
-          }
-        }
-      }
+            WasiCtx.addToLinker(linker);
+            //linker.define("xyz", "poll_word", Extern.fromFunc(pollWordFn));
+            String moduleName = "instance1";
+            linker.module(store, moduleName, module);
+            Extern extern = linker.get(store, moduleName, "").get();
+            Consumer0 doWork = WasmFunctions.consumer(store, extern.func());
+            doWork.accept();
     }
   }
 
-  private static byte[] readWAT(String filename) throws IOException {
-    try (InputStream is = new FileInputStream("/home/curtis/code/kitware/itk-wasm/packages/core/java/src/main/resources/org/itk/wasm/" + filename)) {
-    //try (InputStream is = Main.class.getResourceAsStream(filename)) {
+  private static byte[] readBytes(String filename) throws IOException {
+     //try (InputStream is = Main.class.getResourceAsStream(filename)) {
+    try (InputStream is = new FileInputStream(filename)) {
       ByteArrayOutputStream buffer = new ByteArrayOutputStream();
       int nRead;
       byte[] buf = new byte[16384];