Add the JavaScriptWriter and some tests.

src/de/inetsoftware/jwebassembly/javascript/JavaScriptWriter.java

@@ -0,0 +1,134 @@
+/*
+   Copyright 2019 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.javascript;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import de.inetsoftware.jwebassembly.module.WasmTarget;
+
+/**
+ * Write JavaScipt glue code.
+ * 
+ * @author Volker Berlin
+ */
+public class JavaScriptWriter {
+
+    private WasmTarget                       target;
+
+    /** annotation attribute for the JavaScript content */
+    static final String                      JAVA_SCRIPT_CONTENT = "js";
+
+    private Map<String, Map<String, String>> modules             = new HashMap<>();
+
+    /**
+     * Create a new instance
+     * 
+     * @param target
+     *            the target for the module data.
+     */
+    public JavaScriptWriter( WasmTarget target ) {
+        this.target = target;
+    }
+
+    /**
+     * Add an import from a needed function with import annotation.
+     * 
+     * @param module
+     *            the module name
+     * @param name
+     *            the function name
+     * @param annotationValues
+     *            the other values of the annotation
+     */
+    public void addImport( String module, String name, Map<String, Object> annotationValues ) {
+        String content = (String)annotationValues.get( JAVA_SCRIPT_CONTENT );
+        Map<String, String> moduleEntries = modules.get( module );
+        if( moduleEntries == null ) {
+            modules.put( module, moduleEntries = new HashMap<>() );
+        }
+
+        String old = moduleEntries.put( name, content );
+        if( old != null ) {
+            System.err.println( "Redefine JavaScript function: " + module + "." + name );
+        }
+    }
+
+    /**
+     * Finish the accumulate of imports and write the JavaScript file.
+     * 
+     * @throws IOException
+     *             if any I/O error occur
+     */
+    public void finish() throws IOException {
+        Appendable out = target.getJavaScriptOutput();
+        if( out == null ) {
+            return;
+        }
+        finish( out );
+    }
+
+    /**
+     * Finish the accumulate of imports and write the JavaScript to the Appendable.
+     * 
+     * @param out
+     *            the target for the script
+     * @throws IOException
+     *             if any I/O error occur
+     */
+    void finish( Appendable out ) throws IOException {
+        out.append( "var wasmImports = {\n" );
+        boolean isFirst = true;
+        for( Entry<String, Map<String, String>> module : modules.entrySet() ) {
+            if( !isFirst ) {
+                out.append( ",\n" );
+            }
+            out.append( module.getKey() ).append( ':' );
+            Map<String, String> functions = module.getValue();
+
+            boolean hasContent = false;
+            for( String content : functions.values() ) {
+                if( content != null && !content.isEmpty() ) {
+                    hasContent = true;
+                    break;
+                }
+            }
+
+            if( hasContent ) {
+                out.append( "{\n" );
+
+                // write the function
+                boolean isFirstFunc = true;
+                for( Entry<String, String> func : functions.entrySet() ) {
+                    if( !isFirstFunc ) {
+                        out.append( ",\n" );
+                    }
+                    out.append( func.getKey() ).append( ':' ).append( func.getValue() );
+                    isFirstFunc = false;
+                }
+
+                out.append( "\n}" );
+            } else {
+                out.append( module.getKey() );
+            }
+            isFirst = false;
+        }
+        out.append( "\n}\n" );
+    }
+}

test/de/inetsoftware/jwebassembly/javascript/JavaScriptWriterTest.java

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+package de.inetsoftware.jwebassembly.javascript;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import java.util.Collections;
+
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import de.inetsoftware.jwebassembly.module.WasmTarget;
+
+public class JavaScriptWriterTest {
+
+    @ClassRule
+    public static TemporaryFolder temp = new TemporaryFolder();
+
+    @Test
+    public void single() throws IOException {
+        JavaScriptWriter writer = new JavaScriptWriter( new WasmTarget( temp.newFile() ) );
+        writer.addImport( "Foo", "bar", Collections.singletonMap( JavaScriptWriter.JAVA_SCRIPT_CONTENT, "1 + 1" ) );
+        StringBuilder builder = new StringBuilder();
+        writer.finish( builder );
+        assertEquals( "var wasmImports = {\n" + 
+                        "Foo:{\n" + 
+                        "bar:1 + 1\n" + 
+                        "}\n" + 
+                        "}\n" + 
+                        "", builder.toString() );
+    }
+
+    @Test
+    public void twoFunctions() throws IOException {
+        JavaScriptWriter writer = new JavaScriptWriter( new WasmTarget( temp.newFile() ) );
+        writer.addImport( "Foo", "bar", Collections.singletonMap( JavaScriptWriter.JAVA_SCRIPT_CONTENT, "1 + 1" ) );
+        writer.addImport( "Foo", "xyz", Collections.singletonMap( JavaScriptWriter.JAVA_SCRIPT_CONTENT, "3" ) );
+        StringBuilder builder = new StringBuilder();
+        writer.finish( builder );
+        assertEquals( "var wasmImports = {\n" + 
+                        "Foo:{\n" + 
+                        "bar:1 + 1,\n" + 
+                        "xyz:3\n" + 
+                        "}\n" + 
+                        "}\n" + 
+                        "", builder.toString() );
+    }
+
+    @Test
+    public void twoModules() throws IOException {
+        JavaScriptWriter writer = new JavaScriptWriter( new WasmTarget( temp.newFile() ) );
+        writer.addImport( "Foo", "foo", Collections.singletonMap( JavaScriptWriter.JAVA_SCRIPT_CONTENT, "1 + 1" ) );
+        writer.addImport( "Bar", "bar", Collections.singletonMap( JavaScriptWriter.JAVA_SCRIPT_CONTENT, "3" ) );
+        StringBuilder builder = new StringBuilder();
+        writer.finish( builder );
+        assertEquals( "var wasmImports = {\n" + 
+                        "Bar:{\n" + 
+                        "bar:3\n" + 
+                        "},\n" + 
+                        "Foo:{\n" + 
+                        "foo:1 + 1\n" + 
+                        "}\n" + 
+                        "}\n" + 
+                        "", builder.toString() );
+    }
+
+    @Test
+    public void rootModule() throws IOException {
+        JavaScriptWriter writer = new JavaScriptWriter( new WasmTarget( temp.newFile() ) );
+        writer.addImport( "Foo", "foo", Collections.emptyMap() );
+        writer.addImport( "Foo", "bar", Collections.emptyMap() );
+        StringBuilder builder = new StringBuilder();
+        writer.finish( builder );
+        assertEquals( "var wasmImports = {\n" + 
+                        "Foo:Foo\n" + 
+                        "}\n" + 
+                        "", builder.toString() );
+    }
+}