JavascriptBundleWriter.java

package com.codename1.tools.translator;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

final class JavascriptBundleWriter {
    private static final String RESOURCE_ROOT = "/javascript/";

    private JavascriptBundleWriter() {
    }

    static void write(File outputDirectory, List<ByteCodeClass> classes) throws IOException {
        writeRuntime(outputDirectory);
        writeTranslatedClasses(outputDirectory, classes);
        writeWorker(outputDirectory);
        writeIndex(outputDirectory);
        writeProtocol(outputDirectory);
    }

    private static void writeRuntime(File outputDirectory) throws IOException {
        writeResource(outputDirectory, "parparvm_runtime.js", "parparvm_runtime.js");
    }

    private static void writeTranslatedClasses(File outputDirectory, List<ByteCodeClass> classes) throws IOException {
        StringBuilder out = new StringBuilder();
        List<ByteCodeClass> sorted = new ArrayList<ByteCodeClass>(classes);
        Collections.sort(sorted, new Comparator<ByteCodeClass>() {
            @Override
            public int compare(ByteCodeClass a, ByteCodeClass b) {
                int priorityDiff = bootstrapPriority(a) - bootstrapPriority(b);
                if (priorityDiff != 0) {
                    return priorityDiff;
                }
                return a.getClsName().compareTo(b.getClsName());
            }
        });
        for (ByteCodeClass cls : sorted) {
            out.append(cls.generateJavascriptCode(classes)).append('\n');
        }
        ByteCodeClass mainClass = ByteCodeClass.getMainClass();
        if (mainClass != null) {
            out.append("jvm.setMain(\"").append(mainClass.getClsName()).append("\", \"")
                    .append(JavascriptNameUtil.methodIdentifier(mainClass.getClsName(), "main", "([Ljava/lang/String;)V"))
                    .append("\");\n");
        }
        Files.write(new File(outputDirectory, "translated_app.js").toPath(),
                out.toString().getBytes(StandardCharsets.UTF_8));
    }

    private static int bootstrapPriority(ByteCodeClass cls) {
        String name = cls.getClsName();
        if ("java_lang_Object".equals(name)) {
            return 0;
        }
        if ("java_lang_Class".equals(name)) {
            return 1;
        }
        if ("java_lang_String".equals(name)) {
            return 2;
        }
        if ("java_lang_Throwable".equals(name)) {
            return 3;
        }
        if (name.startsWith("java_lang_String_")) {
            return 4;
        }
        if (name.startsWith("java_lang_")) {
            return 5;
        }
        return 10;
    }

    private static void writeWorker(File outputDirectory) throws IOException {
        List<String> nativeScripts = new ArrayList<String>();
        File[] files = outputDirectory.listFiles();
        if (files != null) {
            for (File file : files) {
                String name = file.getName();
                if (!name.endsWith(".js")) {
                    continue;
                }
                if ("parparvm_runtime.js".equals(name) || "translated_app.js".equals(name) || "worker.js".equals(name)) {
                    continue;
                }
                nativeScripts.add(name);
            }
        }

        StringBuilder imports = new StringBuilder();
        imports.append("importScripts('parparvm_runtime.js');\n");
        for (String script : nativeScripts) {
            imports.append("importScripts('").append(script).append("');\n");
        }
        imports.append("importScripts('translated_app.js');\n");

        String worker = loadResource("worker.js").replace("/*__IMPORTS__*/", imports.toString().trim());
        Files.write(new File(outputDirectory, "worker.js").toPath(), worker.getBytes(StandardCharsets.UTF_8));
    }

    private static void writeIndex(File outputDirectory) throws IOException {
        writeResource(outputDirectory, "index.html", "index.html");
    }

    private static void writeProtocol(File outputDirectory) throws IOException {
        writeResource(outputDirectory, "vm_protocol.md", "vm_protocol.md");
    }

    private static void writeResource(File outputDirectory, String targetName, String resourceName) throws IOException {
        Files.write(new File(outputDirectory, targetName).toPath(),
                loadResource(resourceName).getBytes(StandardCharsets.UTF_8));
    }

    private static String loadResource(String resourceName) throws IOException {
        InputStream input = JavascriptBundleWriter.class.getResourceAsStream(RESOURCE_ROOT + resourceName);
        if (input == null) {
            throw new IOException("Missing javascript backend resource " + resourceName);
        }
        try {
            byte[] data = new byte[8192];
            StringBuilder out = new StringBuilder();
            int len;
            while ((len = input.read(data)) > -1) {
                out.append(new String(data, 0, len, StandardCharsets.UTF_8));
            }
            return out.toString();
        } finally {
            input.close();
        }
    }
}