Reading streams in Java isn't completely easy: Prevent allocating zero length array.
2 * Back 2 Browser Bytecode Translator
3 * Copyright (C) 2012-2015 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, version 2 of the License.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. Look for COPYING file in the top folder.
16 * If not, see http://opensource.org/licenses/GPL-2.0.
18 package org.apidesign.vm4brwsr;
20 import java.io.IOException;
21 import java.io.InputStream;
22 import org.apidesign.bck2brwsr.core.JavaScriptBody;
23 import org.apidesign.vm4brwsr.ByteCodeParser.ClassData;
24 import org.apidesign.vm4brwsr.ByteCodeParser.FieldData;
25 import org.apidesign.vm4brwsr.ByteCodeParser.MethodData;
27 /** Generator of JavaScript from bytecode of classes on classpath of the VM.
29 * @author Jaroslav Tulach <jtulach@netbeans.org>
31 abstract class VM extends ByteCodeToJavaScript {
32 protected final ClassDataCache classDataCache;
34 private final Bck2Brwsr.Resources resources;
35 private final ExportedSymbols exportedSymbols;
36 private final StringBuilder invokerMethods;
37 private final StringArray asBinary;
41 Appendable out, Bck2Brwsr.Resources resources,
42 StringArray explicitlyExported, StringArray asBinary
45 this.resources = resources;
46 this.classDataCache = new ClassDataCache(resources);
47 this.exportedSymbols = new ExportedSymbols(resources, explicitlyExported);
48 this.invokerMethods = new StringBuilder();
49 this.asBinary = asBinary;
53 // uses VMLazy to load dynamic classes
54 boolean assertsOn = false;
55 assert assertsOn = true;
63 boolean debug(String msg) throws IOException {
67 static void compile(Appendable out,
69 ) throws IOException {
70 String[] both = config.classes().toArray();
72 final StringArray fixedNames = new StringArray();
73 fixedNames.add(Object.class.getName().replace('.', '/'));
74 fixedNames.add(Class.class.getName().replace('.', '/'));
75 fixedNames.add(ArithmeticException.class.getName().replace('.', '/'));
78 if (config.isExtension()) {
79 fixedNames.add(VM.class.getName().replace('.', '/'));
80 vm = new Extension(out,
81 config.getResources(), both, config.exported(),
82 config.allResources(), config.classpath()
85 if (config.includeVM()) {
86 fixedNames.add(VM.class.getName().replace('.', '/'));
88 vm = new Standalone(out,
89 config.getResources(), config.exported(),
93 vm.doCompile(fixedNames.addAndNew(both));
96 private void doCompile(StringArray names) throws IOException {
98 append("\n var invoker = {};");
99 append("\n function registerClass(vm, name, fn) {");
100 append("\n if (!vm[name]) vm[name] = fn;");
101 append("\n return vm[name];");
104 append(invokerMethods);
106 for (String r : asBinary.toArray()) {
107 append("\n ").append(getExportsObject()).append("['registerResource']('");
108 append(r).append("', '");
109 InputStream is = this.resources.get(r);
110 int avail = is.available();
114 byte[] arr = new byte[avail];
117 if (offset == arr.length) {
118 byte[] tmp = new byte[arr.length * 2];
119 System.arraycopy(arr, 0, tmp, 0, arr.length);
122 int len = is.read(arr, offset, arr.length - offset);
128 if (offset != arr.length) {
129 byte[] tmp = new byte[offset];
130 System.arraycopy(arr, 0, tmp, 0, offset);
141 @JavaScriptBody(args = { "arr" }, body = "return btoa(arr);")
142 private static String btoa(byte[] arr) {
143 return javax.xml.bind.DatatypeConverter.printBase64Binary(arr);
146 protected abstract void generatePrologue() throws IOException;
148 protected abstract void generateEpilogue() throws IOException;
150 protected abstract String getExportsObject();
152 protected abstract boolean isExternalClass(String className);
154 protected abstract void lazyReference(Appendable out, String n) throws IOException;
157 protected final void declareClass(ClassData classData, String mangledName)
159 if (exportedSymbols.isExported(classData)) {
160 append("registerClass(").append(getExportsObject()).append(",'")
171 protected String generateClass(String className) throws IOException {
172 ClassData classData = classDataCache.getClassData(className);
173 if (classData == null) {
174 throw new IOException("Can't find class " + className);
176 return compile(classData);
180 protected void declaredField(FieldData fieldData,
182 String mangledName) throws IOException {
183 if (exportedSymbols.isExported(fieldData)) {
184 exportMember(destObject, mangledName);
189 protected void declaredMethod(MethodData methodData,
191 String mangledName) throws IOException {
192 if (isHierarchyExported(methodData)) {
193 exportMember(destObject, mangledName);
197 private void exportMember(String destObject, String memberName)
199 append("\n").append(destObject).append("['")
201 .append("'] = m;\n");
204 private void generateBody(StringArray names) throws IOException {
205 StringArray processed = new StringArray();
206 StringArray initCode = new StringArray();
207 StringArray skipClass = new StringArray();
208 for (String baseClass : names.toArray()) {
209 references.add(baseClass);
212 for (String n : references.toArray()) {
213 if (skipClass.contains(n)) {
216 if (processed.contains(n)) {
224 InputStream is = resources.get(name + ".class");
226 lazyReference(this, name);
231 String ic = generateClass(name);
233 initCode.add(ic == null ? "" : ic);
234 } catch (RuntimeException ex) {
235 throw new IOException("Error while compiling " + name + "\n", ex);
239 for (String resource : scripts.toArray()) {
240 while (resource.startsWith("/")) {
241 resource = resource.substring(1);
243 requireResourceImpl(resource);
244 asBinary.remove(resource);
246 scripts = new StringArray();
248 StringArray toInit = StringArray.asList(references.toArray());
251 for (String ic : toInit.toArray()) {
252 int indx = processed.indexOf(ic);
254 final String theCode = initCode.toArray()[indx];
255 if (!theCode.isEmpty()) {
256 append(theCode).append("\n");
258 initCode.toArray()[indx] = "";
264 final void requireResourceImpl(String resource) throws IOException {
265 InputStream emul = resources.get(resource);
267 throw new IOException("Can't find " + resource);
269 append("\n// resource from ").append(resource).append("\n");
270 readResource(emul, this);
274 private static void readResource(InputStream emul, Appendable out) throws IOException {
278 int ch = emul.read();
282 if (ch < 0 || ch > 255) {
283 throw new IOException("Invalid char in emulation " + ch);
285 out.append((char)ch);
292 static String toString(String name) throws IOException {
293 StringBuilder sb = new StringBuilder();
294 // compile(sb, name);
295 return sb.toString().toString();
298 private StringArray scripts = new StringArray();
299 private StringArray references = new StringArray();
302 protected boolean requireReference(String cn) {
303 return references.addIfMissing(cn);
307 protected void requireScript(String resourcePath) {
308 scripts.add(resourcePath);
312 String assignClass(String className) {
313 return "vm." + className + " = ";
317 String accessClass(String className) {
318 return "vm." + className;
322 protected FieldData findField(String[] fieldInfoName) throws IOException {
323 FieldData field = classDataCache.findField(
324 fieldInfoName[0], fieldInfoName[1], fieldInfoName[2]
326 return field != null && canAccessDirectly(field.cls) ? field : null;
330 protected String accessField(String object, FieldData field, String[] fieldInfoName)
332 if (field != null && !field.isStatic()) {
333 return "fld_" + object + "_" + field.getName();
335 String mangledName = "_" + fieldInfoName[1];
336 return accessNonVirtualMember(
337 object, mangledName, field != null ? field.cls : null
343 protected String accessStaticMethod(
346 String[] fieldInfoName) throws IOException {
347 final MethodData method =
348 classDataCache.findMethod(fieldInfoName[0],
351 return accessNonVirtualMember(object, mangledName,
352 (method != null) ? method.cls : null);
356 protected String accessVirtualMethod(
359 String[] fieldInfoName,
361 ) throws IOException {
362 final ClassData referencedClass =
363 classDataCache.getClassData(fieldInfoName[0]);
364 final MethodData method =
365 classDataCache.findMethod(referencedClass,
370 && !isExternalClass(method.cls.getClassName())
371 && (((method.access & ByteCodeParser.ACC_FINAL) != 0)
372 || ((referencedClass.getAccessFlags()
373 & ByteCodeParser.ACC_FINAL) != 0)
374 || !isHierarchyExported(method))) {
375 return object + "." + mangledName + '(';
378 return accessThroughInvoker(object, mangledName, params);
381 private String accessThroughInvoker(String object, String mangledName, int params)
383 String def = "\n invoker." + mangledName + " = function(target";
384 if (invokerMethods.indexOf(def) == -1) {
385 invokerMethods.append(def);
386 for (int j = 0; j < params; j++) {
387 invokerMethods.append(", p").append(j);
389 invokerMethods.append(") {\n return target['").
390 append(mangledName).append("'](");
391 for (int j = 0; j < params; j++) {
393 invokerMethods.append(",");
395 invokerMethods.append("p").append(j);
397 invokerMethods.append(");\n };");
399 return "invoker." + mangledName + '(' + object + (params > 1 ? "," : "");
402 private boolean isHierarchyExported(final MethodData methodData)
404 if (exportedSymbols.isExported(methodData)) {
407 if ((methodData.access & (ByteCodeParser.ACC_PRIVATE
408 | ByteCodeParser.ACC_STATIC)) != 0) {
412 final ExportedMethodFinder exportedMethodFinder =
413 new ExportedMethodFinder(exportedSymbols);
415 classDataCache.findMethods(
417 methodData.getName(),
418 methodData.getInternalSig(),
419 exportedMethodFinder);
421 return (exportedMethodFinder.getFound() != null);
424 private boolean canAccessDirectly(ClassData declaringClass) {
425 if (declaringClass == null) {
428 final String className = declaringClass.getClassName();
430 "java/lang/Object".equals(className) ||
431 "java/lang/reflect/Array".equals(className) ||
432 isExternalClass(className)
439 private String accessNonVirtualMember(
440 String object, String mangledName, ClassData declaringClass
442 return canAccessDirectly(declaringClass) ?
443 object + "." + mangledName :
444 object + "['" + mangledName + "']";
447 private final class ExportedMethodFinder
448 implements ClassDataCache.TraversalCallback<MethodData> {
449 private final ExportedSymbols exportedSymbols;
450 private MethodData found;
452 public ExportedMethodFinder(final ExportedSymbols exportedSymbols) {
453 this.exportedSymbols = exportedSymbols;
457 public boolean traverse(final MethodData methodData) {
460 exportedSymbols.isExported(methodData) ||
461 isExternalClass(methodData.cls.getClassName())
466 } catch (final IOException e) {
472 public MethodData getFound() {
477 private static final class Standalone extends VM {
478 private Standalone(Appendable out,
479 Bck2Brwsr.Resources resources,
480 StringArray explicitlyExported, StringArray asBinary
482 super(out, resources, explicitlyExported, asBinary);
486 protected void generatePrologue() throws IOException {
487 append("(function VM(global) {var fillInVMSkeleton = function(vm) {");
491 protected void generateEpilogue() throws IOException {
495 + " var extensions = [];\n"
496 + " function replaceAll(s, target, replacement) {\n"
499 + " var indx = s.indexOf(target, pos);\n"
500 + " if (indx === -1) {\n"
503 + " pos = indx + replacement.length;\n"
504 + " s = s.substring(0, indx) + replacement + s.substring(indx + target.length);\n"
507 + " function mangleClass(name) {\n"
508 + " name = replaceAll(name, '_', '_1');\n"
509 + " name = replaceAll(name, '.', '_');\n"
512 + " var pending = [];\n"
513 + " var pendingClasses = [];\n"
514 + " function extensionLoaded(ev) {\n"
515 + " var at = pending.indexOf(ev.target);\n"
516 + " pending.splice(at, 1);\n"
517 + " if (pending.length === 0) {\n"
518 + " for (var i = 0; i < pendingClasses.length; i += 3) {\n"
519 + " invokeMethod(pendingClasses[i], pendingClasses[i + 1], pendingClasses[i + 2]);\n"
521 + " pendingClasses = [];\n"
524 + " function invokeMethod(vm, n, args) {\n"
525 + " var clazz = vm.loadClass(n);\n"
527 + " var seek = args[0];\n"
528 + " var prefix = seek.indexOf('__') == -1 ? seek + '__' : seek;\n"
529 + " args = Array.prototype.slice.call(args, 1);\n"
530 + " var found = '';\n"
531 + " for (var m in clazz) {\n"
532 + " if (m.indexOf(prefix) === 0) {\n"
533 + " return clazz[m].apply(null, args);\n"
535 + " found += m.toString() + '\\n'\n"
537 + " throw 'Cannot find ' + seek + ' in ' + n + ' found:\\n' + found;\n"
540 + " function extensionError(ev) {\n"
541 + " console.log('error loading ' + ev.target.src);\n"
542 + " extensionLoaded(ev);\n"
544 + " function loadExtension(url) {\n"
545 + " if (url.substring(url.length - 4) == '.jar')\n"
546 + " url = url.substring(0, url.length - 4) + '.js';\n"
547 + " var script = document.createElement('script');\n"
548 + " script.type = 'text/javascript';\n"
549 + " script.src = url;\n"
550 + " script.onload = extensionLoaded;\n"
551 + " script.onerror = extensionError;\n"
552 + " document.getElementsByTagName('head')[0].appendChild(script);\n"
553 + " pending.push(script);\n"
555 + " global.bck2brwsr = function() {\n"
556 + " var args = Array.prototype.slice.apply(arguments);\n"
557 + " var resources = {};\n"
558 + " function registerResource(n, a64) {\n"
559 + " var frm = atob || window.atob;\n"
560 + " var str = frm(a64);\n"
562 + " for (var i = 0; i < str.length; i++) {\n"
563 + " var ch = str.charCodeAt(i) & 0xff;\n"
564 + " if (ch > 127) ch -= 256;\n"
567 + " if (!resources[n]) resources[n] = [arr];\n"
568 + " else resources[n].push(arr);\n"
570 + " var vm = fillInVMSkeleton({ 'registerResource' : registerResource });\n"
571 + " function initVM() {\n"
572 + " var clsArray = vm['java_lang_reflect_Array'];\n"
573 + " if (clsArray) clsArray(false);\n"
575 + " for (var i = 0; i < extensions.length; ++i) {\n"
576 + " extensions[i](vm);\n"
578 + " vm['registerResource'] = null;\n"
579 + " var knownExtensions = extensions.length;\n"
580 + " var loader = {};\n"
581 + " var loadBytes = function(name, skip) {\n"
582 + " skip = typeof skip == 'number' ? skip : 0;\n"
583 + " var arr = resources[name];\n"
585 + " var arrSize = arr.length;\n"
586 + " if (skip < arrSize) return arr[skip];\n"
587 + " skip -= arrSize;\n"
589 + " var arrSize = 0;\n"
591 + " for (var i = 0; i < args.length; i++) {\n"
592 + " var at = args[i];\n"
593 + " if(!at) continue;\n"
595 + " if (typeof at === 'string' && at.substring(at.length - 3) === '.js') {\n"
596 + " loadExtension(at);\n"
597 + " args[i] = null;\n"
598 + " } else if (typeof at === 'function') ret = at(name, skip);\n"
600 + " var cp = vm['org_apidesign_vm4brwsr_ClassPath'];\n"
601 + " if (!cp) throw 'Core Java library not registered. Cannot load from ' + at;\n"
602 + " ret = cp(false).\n"
603 + " loadBytes___3BLjava_lang_String_2Ljava_lang_Object_2II(name, args, i, skip);\n"
605 + " if (ret) return ret;\n"
607 + " while (knownExtensions < extensions.length) {\n"
608 + " vm['registerResource'] = registerResource;\n"
609 + " extensions[knownExtensions++](vm);\n"
610 + " vm['registerResource'] = null;\n"
613 + " var arr = resources[name];\n"
614 + " return (arr && arr.length > arrSize) ? arr[arrSize] : null;\n"
616 + " var reload = function(name, arr, keep) {\n"
617 + " if (!arr) throw 'Cannot find ' + name;\n"
618 + " var lazy = vm['org_apidesign_vm4brwsr_VMLazy'];\n"
619 + " if (!lazy) throw 'No bck2brwsr VM module to compile ' + name;\n"
621 + " var attr = mangleClass(name);\n"
622 + " delete vm[attr];\n"
624 + " return lazy(false)\n"
625 + " ['load__Ljava_lang_Object_2Ljava_lang_Object_2Ljava_lang_String_2_3Ljava_lang_Object_2_3B']\n"
626 + " (vm, name, args, arr);\n"
628 + " var loadClass = function(name) {\n"
629 + " var attr = mangleClass(name);\n"
630 + " var fn = vm[attr];\n"
631 + " if (fn) return fn(false);\n"
633 + " var arr = loadBytes(replaceAll(name, '.', '/') + '.class');\n"
634 + " return reload(name, arr, true);\n"
635 + " } catch (err) {\n"
636 + " fn = vm[attr];\n"
637 + " if (fn) return fn(false);\n"
641 + " if (vm['loadClass']) {\n"
642 + " throw 'Cannot initialize the bck2brwsr VM twice!';\n"
644 + " vm['loadClass'] = loadClass;\n"
645 + " vm['_reload'] = reload;\n"
646 + " vm['loadBytes'] = loadBytes;\n"
648 + " loader.loadClass = function(name) {\n"
649 + " if (pending.length === 0) {\n"
651 + " var c = loadClass(name);\n"
652 + " c['invoke'] = function() {\n"
653 + " return invokeMethod(vm, name, arguments);\n"
656 + " } catch (err) {\n"
657 + " if (pending.length === 0) throw err;\n"
660 + " pendingClasses.push(vm);\n"
661 + " pendingClasses.push(name);\n"
662 + " pendingClasses.push(null);\n"
664 + " 'invoke' : function() {\n"
665 + " if (pending.length === 0) {\n"
666 + " invokeMethod(vm, name, arguments);\n"
669 + " pendingClasses.push(vm);\n"
670 + " pendingClasses.push(name);\n"
671 + " pendingClasses.push(arguments);\n"
675 + " return loader;\n"
678 " global.bck2brwsr.register = function(config, extension) {\n"
679 + " if (!config || config['magic'] !== 'kafčo') {\n"
680 + " console.log('Will not register: ' + extension);\n"
683 + " var cs = typeof document == 'undefined' ? null : document['currentScript'];\n"
684 + " var prefix = cs ? cs['src']['replace'](/\\/[^\\/]*$/,'/') : '';\n"
685 + " extensions.push(extension);\n"
686 + " var cp = config['classpath'];\n"
687 + " if (cp) for (var i = 0; i < cp.length; i++) {\n"
688 + " loadExtension(prefix + cp[i]);\n"
696 protected String getExportsObject() {
701 protected boolean isExternalClass(String className) {
706 protected void lazyReference(Appendable out, String n) throws IOException {
707 String cls = n.replace('/', '_');
708 String dot = n.replace('/', '.');
710 out.append("\nvm.").append(cls).append(" = function() {");
711 out.append("\n var instance = arguments.length == 0 || arguments[0] === true;");
712 out.append("\n delete vm.").append(cls).append(";");
713 out.append("\n var c = vm.loadClass('").append(dot).append("');");
714 out.append("\n return vm.").append(cls).append("(instance);");
719 protected void requireResource(String resourcePath) throws IOException {
720 requireResourceImpl(resourcePath);
721 super.asBinary.remove(resourcePath);
725 private static final class Extension extends VM {
726 private final StringArray extensionClasses;
727 private final StringArray classpath;
729 private Extension(Appendable out, Bck2Brwsr.Resources resources,
730 String[] extClassesArray, StringArray explicitlyExported,
731 StringArray asBinary, StringArray classpath
732 ) throws IOException {
733 super(out, resources, explicitlyExported, asBinary);
734 this.extensionClasses = StringArray.asList(extClassesArray);
735 this.classpath = classpath;
739 protected void generatePrologue() throws IOException {
741 "bck2brwsr.register({\n"
742 + " 'magic' : 'kafčo'"
744 if (classpath != null && classpath.toArray().length > 0) {
746 ",\n 'classpath' : [\n"
749 for (String s : classpath.toArray()) {
750 append(sep).append("'").append(s).append("'");
758 "\n}, function(exports) {\n"
759 + " var vm = {};\n");
760 append(" function link(n, assign) {\n"
761 + " return function() {\n"
762 + " var no_ = n['replace__Ljava_lang_String_2Ljava_lang_CharSequence_2Ljava_lang_CharSequence_2']"
763 + "('_', '_1').toString();\n"
764 + " var cls = no_['replace__Ljava_lang_String_2CC']"
765 + "('/', '_').toString();\n"
766 + " var dot = n['replace__Ljava_lang_String_2CC']"
767 + "('/', '.').toString();\n"
768 + " exports.loadClass(dot);\n"
769 + " assign(exports[cls]);\n"
770 + " return exports[cls](arguments);\n"
777 protected void generateEpilogue() throws IOException {
779 if (exportedCount == 0) {
780 throw new IOException("Creating library without any exported symbols is useless!");
785 protected String generateClass(String className) throws IOException {
786 if (isExternalClass(className)) {
787 final String cls = className.replace("_", "_1").replace('/', '_');
788 append("\n").append(assignClass(cls))
791 .append("', function(f) { ").append(assignClass(cls)).append(" f; });");
796 return super.generateClass(className);
800 protected String getExportsObject() {
805 protected boolean isExternalClass(String className) {
806 return !extensionClasses.contains(className);
810 protected void lazyReference(Appendable out, String n) throws IOException {
811 String cls = n.replace('/', '_');
813 out.append("\nvm.").append(cls).append(" = function() {");
814 out.append("\n var instance = arguments.length == 0 || arguments[0] === true;");
815 out.append("\n delete vm.").append(cls).append(";");
816 out.append("\n return link('").append(n).append("', function(f) { vm.");
817 out.append(cls).append(" = f;})(instance);");
822 protected void requireResource(String resourcePath) throws IOException {
823 requireResourceImpl(resourcePath);
824 super.asBinary.remove(resourcePath);