Add emulator for JWebAssembly

Author: Horcrux7

src/de/inetsoftware/jwebassembly/emulator/ImportAnnotation.java

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+/*
+ * Copyright 2020 Volker Berlin (i-net software)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.inetsoftware.jwebassembly.emulator;
+
+/**
+ * The values of a scanned import annotation.
+ * 
+ * @author Volker Berlin
+ */
+class ImportAnnotation {
+
+    String module;
+
+    String name;
+
+    String javaScript;
+}

src/de/inetsoftware/jwebassembly/emulator/ImportAnnotationClassVisitor.java

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+/*
+ * Copyright 2020 Volker Berlin (i-net software)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.inetsoftware.jwebassembly.emulator;
+
+import static org.objectweb.asm.Opcodes.ACC_NATIVE;
+import static org.objectweb.asm.Opcodes.ASM7;
+
+import java.util.Map;
+
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.MethodVisitor;
+
+/**
+ * Scan a class for native methods with Import annotations.
+ * 
+ * @author Volker Berlin
+ */
+class ImportAnnotationClassVisitor extends ClassVisitor {
+
+    private String                        className;
+
+    private Map<String, ImportAnnotation> annotations;
+
+    /**
+     * Create an instance.
+     * 
+     * @param className
+     *            the name of the class in the internal form of fully qualified class. For example, "java/util/List".
+     * @param annotations
+     *            container for found annotations, key is method name with signature
+     */
+    ImportAnnotationClassVisitor( String className, Map<String, ImportAnnotation> annotations ) {
+        super( ASM7 );
+        this.className = className;
+        this.annotations = annotations;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public MethodVisitor visitMethod( int access, String name, String descriptor, String signature, String[] exceptions ) {
+        if( (access & ACC_NATIVE) > 0 ) {
+            // start scanning of annotations if it is a native method
+            return new ImportAnnotationMethodVisitor( className, name, descriptor, annotations );
+        }
+
+        // skip all other methods
+        return null;
+    }
+}

src/de/inetsoftware/jwebassembly/emulator/ImportAnnotationMethodVisitor.java

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+/*
+ * Copyright 2020 Volker Berlin (i-net software)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.inetsoftware.jwebassembly.emulator;
+
+import java.util.Map;
+
+import org.objectweb.asm.AnnotationVisitor;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.Type;
+
+import de.inetsoftware.jwebassembly.api.annotation.Import;
+
+/**
+ * Search for methods with the Import annotation of JWebAssembly.
+ * 
+ * @author Volker Berlin
+ */
+class ImportAnnotationMethodVisitor extends MethodVisitor {
+
+    private static final String           IMPORT_ANN = Type.getDescriptor( Import.class );
+
+    private String                        className;
+
+    private String                        methodName;
+
+    private String                        descriptor;
+
+    private Map<String, ImportAnnotation> annotations;
+
+    /**
+     * Create an instance.
+     * 
+     * @param className
+     *            the name of the class in the internal form of fully qualified class. For example, "java/util/List".
+     * @param methodName
+     *            method name
+     * @param descriptor
+     *            the method's descriptor (see {@link Type}).
+     * @param annotations
+     *            container for found annotations, key is method name with signature
+     */
+    ImportAnnotationMethodVisitor( String className, String methodName, String descriptor, Map<String, ImportAnnotation> annotations ) {
+        super( Opcodes.ASM7 );
+        this.className = className;
+        this.methodName = methodName;
+        this.descriptor = descriptor;
+        this.annotations = annotations;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public AnnotationVisitor visitAnnotation( String descriptor, boolean visible ) {
+        if( IMPORT_ANN.equals( descriptor ) ) {
+            return new ImportAnnotationVisitor( className, methodName, this.descriptor, annotations );
+        }
+        return null;
+    }
+
+}

src/de/inetsoftware/jwebassembly/emulator/ImportAnnotationVisitor.java

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+/*
+ * Copyright 2020 Volker Berlin (i-net software)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.inetsoftware.jwebassembly.emulator;
+
+import static org.objectweb.asm.Opcodes.ASM7;
+
+import java.util.Map;
+
+import org.objectweb.asm.AnnotationVisitor;
+import org.objectweb.asm.Type;
+
+/**
+ * Scan the values of an Import annotation
+ * 
+ * @author Volker Berlin
+ */
+class ImportAnnotationVisitor extends AnnotationVisitor {
+
+    private ImportAnnotation anno;
+
+    /**
+     * Create an instance and add an ImportAnnotation to the container.
+     * 
+     * @param className
+     *            the name of the class in the internal form of fully qualified class. For example, "java/util/List".
+     * @param methodName
+     *            method name
+     * @param descriptor
+     *            the method's descriptor (see {@link Type}).
+     * @param annotations
+     *            container for found annotations, key is method name with signature
+     */
+    public ImportAnnotationVisitor( String className, String methodName, String descriptor, Map<String, ImportAnnotation> annotations ) {
+        super( ASM7 );
+        annotations.put( methodName + descriptor, anno = new ImportAnnotation() );
+        // default values for module and name
+        anno.module = className.substring( className.lastIndexOf( '/' ) + 1 );
+        anno.name = methodName;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void visit( String name, Object value ) {
+        switch( name ) {
+            case "module":
+                anno.module = (String)value;
+                break;
+            case "name":
+                anno.name = (String)value;
+                break;
+            case "js":
+                anno.javaScript = (String)value;
+                break;
+        }
+    }
+}

src/de/inetsoftware/jwebassembly/emulator/JWebAssemblyEmulator.java

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+/*
+ * Copyright 2020 Volker Berlin (i-net software)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.inetsoftware.jwebassembly.emulator;
+
+import java.net.URL;
+
+import javax.annotation.Nonnull;
+
+import javafx.application.Application;
+import javafx.concurrent.Worker;
+import javafx.scene.Scene;
+import javafx.scene.layout.VBox;
+import javafx.scene.web.WebEngine;
+import javafx.scene.web.WebView;
+import javafx.stage.Stage;
+import netscape.javascript.JSException;
+import netscape.javascript.JSObject;
+
+/**
+ * The main class start point for the emulator.
+ * 
+ * @author Volker Berlin
+ */
+@SuppressWarnings( "restriction" )
+public class JWebAssemblyEmulator {
+
+    static {
+        // move the JavaScript console to System.out
+        com.sun.javafx.webkit.WebConsoleListener.setDefaultListener( ( webView, message, lineNumber, sourceId ) -> {
+            System.out.println( message + "[at " + lineNumber + "]" );
+        } );
+    }
+
+    /**
+     * Start the emulator, load the html page and call the given main method.
+     * 
+     * @param htmlPage
+     *             The resource of the html page that the WebAssembly contains.
+     * @param main
+     *            the executable with the main function
+     */
+    public static void launch( @Nonnull String htmlPage, @Nonnull Runnable main ) {
+        launch( ClassLoader.getSystemResource( htmlPage ), main );
+    }
+
+    /**
+     * Start the emulator, load the html page and call the given main method.
+     * 
+     * @param htmlPageURL
+     *             The URL of the html page that the WebAssembly contains.
+     * @param main
+     *            the executable with the main function
+     */
+    public static void launch( @Nonnull URL htmlPageURL, @Nonnull Runnable main ) {
+        JavaFxApplication.url = htmlPageURL.toString();
+        JavaFxApplication.main = main;
+
+        JavaFxApplication.launch( JavaFxApplication.class, new String[0] );
+    }
+
+    /**
+     * The implementation of the javafx Application.
+     * 
+     * @author Volker Berlin
+     */
+    public static class JavaFxApplication extends Application {
+
+        private static String    url;
+
+        private static Runnable  main;
+
+        private static WebEngine webEngine;
+
+        private static JSObject  wasmImports;
+
+        /**
+         * register a JavaScript function from a nation method with annotation in the wasmimports
+         * 
+         * @param anno
+         *            the annotation
+         */
+        static void registerScript( @Nonnull ImportAnnotation anno ) {
+            Object obj = wasmImports.getMember( anno.module );
+            if( "undefined".equals( obj ) ) {
+                webEngine.executeScript( "wasmImports." + anno.module + " = {}" );
+            }
+
+            webEngine.executeScript( "wasmImports." + anno.module + "." + anno.name + "=" + anno.javaScript );
+        }
+
+        /**
+         * The bridge method for the WebAssembly import function into the JavaScript.
+         * 
+         * @param moduleName
+         *            the name of the module
+         * @param methodName
+         *            the name of the function
+         * @param args
+         *            the arguments
+         * @return the return value if any
+         */
+        public static Object executeScript( String moduleName, String methodName, Object... args ) {
+            JSObject module = (JSObject)wasmImports.getMember( moduleName );
+
+            return module.call( methodName, args );
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        @Override
+        public void start( Stage primaryStage ) throws Exception {
+            // Create a WebView
+            WebView browser = new WebView();
+
+            // Get WebEngine via WebView
+            webEngine = browser.getEngine();
+            // https://stackoverflow.com/questions/41654573/java-fx-javascript
+            Worker<Void> worker = webEngine.getLoadWorker();
+            worker.stateProperty().addListener( ( obs, old, neww ) -> {
+                if( neww == Worker.State.SUCCEEDED ) {
+                    try {
+                        wasmImports = (JSObject)webEngine.executeScript( "wasmImports" );
+                    } catch( JSException e ) {
+                        webEngine.executeScript( "var wasmImports = {}" );
+                        wasmImports = (JSObject)webEngine.executeScript( "wasmImports" );
+                    }
+                    main.run();
+                }
+            } );
+            // Load page
+            webEngine.load( url );
+
+            VBox vBox = new VBox( browser );
+            Scene scene = new Scene( vBox );
+
+            primaryStage.setTitle( "JWebAssembly Emulator" );
+            primaryStage.setScene( scene );
+            primaryStage.show();
+        }
+    }
+}