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/*
 * Copyright 2008 Google Inc.
 *
 * 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 com.google.gwt.dev.shell;

import com.google.gwt.dev.javac.JsniMethod;
import com.google.gwt.dev.jjs.SourceInfo;
import com.google.gwt.dev.js.JsSourceGenerationVisitor;
import com.google.gwt.dev.js.ast.JsContext;
import com.google.gwt.dev.js.ast.JsExpression;
import com.google.gwt.dev.js.ast.JsFunction;
import com.google.gwt.dev.js.ast.JsInvocation;
import com.google.gwt.dev.js.ast.JsNameRef;
import com.google.gwt.dev.js.ast.JsNode;
import com.google.gwt.dev.js.ast.JsNullLiteral;
import com.google.gwt.dev.js.ast.JsNumberLiteral;
import com.google.gwt.dev.util.DefaultTextOutput;
import com.google.gwt.dev.util.TextOutput;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.List;

/**
 * Helper methods working with JSNI.
 */
public class Jsni {

  /**
   * Generate source code, fixing up any JSNI references for hosted mode.
   *
   * 

*

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
OriginalBecomes
obj.@class::method(params)(args)__gwt_makeJavaInvoke(paramCount)(obj, dispId, args)
@class::method(params)(args)__gwt_makeJavaInvoke(paramCount)(null, dispId, args)
obj.@class::method(params)__gwt_makeTearOff(obj, dispId, paramCount)
@class::method(params)__gwt_makeTearOff(null, dispId, paramCount)
obj.@class::fieldobj[dispId]
@class::field__static[dispId]
*/ private static class JsSourceGenWithJsniIdentFixup extends JsSourceGenerationVisitor { private final DispatchIdOracle dispatchInfo; private final TextOutput out; public JsSourceGenWithJsniIdentFixup(TextOutput out, DispatchIdOracle ccl) { super(out); this.dispatchInfo = ccl; this.out = out; } /** * This will handle references to fields or tear-offs of Java methods. */ @Override public boolean visit(JsNameRef x, JsContext ctx) { String ident = x.getIdent(); JsExpression q = x.getQualifier(); if (ident.startsWith("@")) { int dispId = dispatchInfo.getDispId(ident); Member member; if (dispId < 0) { member = null; } else { member = dispatchInfo.getClassInfoByDispId(dispId).getMember(dispId); } if (member == null) { throw new HostedModeException( "JSNI rewriter found reference to non-existent field in a field reference or java method tear-off: " + ident + " at " + x.getSourceInfo()); } if (member instanceof Field || member instanceof SyntheticClassMember) { if (q != null) { accept(q); out.print("["); out.print(String.valueOf(dispId)); out.print("]"); } else { out.print("__static["); out.print(String.valueOf(dispId)); out.print("]"); } return false; } int paramCount = 0; if (member instanceof Method) { paramCount = ((Method) member).getParameterTypes().length; } else if (member instanceof Constructor) { paramCount = ((Constructor) member).getParameterTypes().length; } // Use a clone instead of modifying the original JSNI // __gwt_makeTearOff(obj, dispId, paramCount) SourceInfo info = x.getSourceInfo(); JsInvocation rewritten = new JsInvocation(info, new JsNameRef(info, "__gwt_makeTearOff")); List arguments = rewritten.getArguments(); if (q == null) { q = JsNullLiteral.INSTANCE; } arguments.add(q); arguments.add(new JsNumberLiteral(info, dispId)); arguments.add(new JsNumberLiteral(info, paramCount)); accept(rewritten); return false; } return super.visit(x, ctx); } /** * Handles immediate invocations of JSNI method references. This has to be * done through a wonky method "__gwt_makeJavaInvoke" to handle exceptions * correctly on some browsers. */ @Override public boolean visit(JsInvocation x, JsContext ctx) { if (x.getQualifier() instanceof JsNameRef) { JsNameRef ref = (JsNameRef) x.getQualifier(); String ident = ref.getIdent(); if (ident.startsWith("@")) { int dispId = dispatchInfo.getDispId(ident); Member member; if (dispId < 0) { member = null; } else { member = dispatchInfo.getClassInfoByDispId(dispId).getMember(dispId); } if (member == null) { throw new HostedModeException( "JSNI rewriter found reference to non-existent field in a method invocation: " + ref.getIdent() + " at " + ref.getSourceInfo()); } /* * Make sure the ident is a reference to a method or constructor and * not a reference to a field whose contents (e.g. a Function) we * intend to immediately invoke. * * p.C::method()(); versus p.C::field(); */ if (member instanceof Method || member instanceof Constructor) { // Use a clone instead of modifying the original JSNI // __gwt_makeJavaInvoke(paramCount)(obj, dispId, args) int paramCount = 0; if (member instanceof Method) { paramCount = ((Method) member).getParameterTypes().length; } else if (member instanceof Constructor) { paramCount = ((Constructor) member).getParameterTypes().length; } SourceInfo info = x.getSourceInfo(); JsInvocation inner = new JsInvocation(info, new JsNameRef(info, "__gwt_makeJavaInvoke"), new JsNumberLiteral(info, paramCount)); JsInvocation outer = new JsInvocation(info); outer.setQualifier(inner); JsExpression q = ref.getQualifier(); if (q == null) { q = JsNullLiteral.INSTANCE; } List arguments = outer.getArguments(); arguments.add(q); arguments.add(new JsNumberLiteral(info, dispId)); arguments.addAll(x.getArguments()); accept(outer); return false; } } } return super.visit(x, ctx); } } /** * Gets the body of a JSNI method, with Java refs escaped for hosted mode * injection. */ public static String getJavaScriptForHostedMode( DispatchIdOracle dispatchInfo, JsniMethod jsniMethod) { JsFunction func = jsniMethod.function(); if (func == null) { return null; } return generateJavaScriptForHostedMode(dispatchInfo, func.getBody()); } /** * Returns a string representing the source output of the JsNode, where all * JSNI idents have been replaced with legal JavaScript for hosted mode. */ private static String generateJavaScriptForHostedMode( DispatchIdOracle dispatchInfo, JsNode node) { DefaultTextOutput out = new DefaultTextOutput(false); JsSourceGenWithJsniIdentFixup vi = new JsSourceGenWithJsniIdentFixup(out, dispatchInfo); vi.accept(node); return out.toString(); } }




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