/*
* 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.
*
* <p/>
* <table>
* <tr>
* <td>Original</td>
* <td>Becomes</td>
* </tr>
* <tr>
* <td><code>obj.@class::method(params)(args)</code></td>
*
* <td><code>__gwt_makeJavaInvoke(paramCount)(obj, dispId, args)</code></td>
* </tr>
* <tr>
* <td><code>@class::method(params)(args)</code></td>
*
* <td><code>__gwt_makeJavaInvoke(paramCount)(null, dispId, args)</code></td>
* </tr>
* <tr>
* <td><code>obj.@class::method(params)</code></td>
*
* <td><code>__gwt_makeTearOff(obj, dispId, paramCount)</code></td>
* </tr>
* <tr>
* <td><code>@class::method(params)</code></td>
*
* <td><code>__gwt_makeTearOff(null, dispId, paramCount)</code></td>
* </tr>
* <tr>
* <td><code>obj.@class::field</code></td>
*
* <td><code>obj[dispId]</code></td>
* </tr>
* <tr>
* <td><code>@class::field</code></td>
*
* <td><code>__static[dispId]</code></td>
* </tr>
* </table>
*/
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);
rewritten.setQualifier(new JsNameRef(info, "__gwt_makeTearOff"));
List<JsExpression> 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);
inner.setQualifier(new JsNameRef(info, "__gwt_makeJavaInvoke"));
inner.getArguments().add(new JsNumberLiteral(info, paramCount));
JsInvocation outer = new JsInvocation(info);
outer.setQualifier(inner);
JsExpression q = ref.getQualifier();
if (q == null) {
q = JsNullLiteral.INSTANCE;
}
List<JsExpression> 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);
}
}
public static final String JAVASCRIPTHOST_NAME = JavaScriptHost.class.getName();
/**
* 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();
}
}