/*
* 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.jdt;
import com.google.gwt.dev.javac.JsniCollector;
import com.google.gwt.dev.jjs.InternalCompilerException;
import com.google.gwt.dev.jjs.SourceOrigin;
import com.google.gwt.dev.js.JsParser;
import com.google.gwt.dev.js.JsParserException;
import com.google.gwt.dev.js.ast.JsContext;
import com.google.gwt.dev.js.ast.JsExpression;
import com.google.gwt.dev.js.ast.JsNameRef;
import com.google.gwt.dev.js.ast.JsProgram;
import com.google.gwt.dev.js.ast.JsStatement;
import com.google.gwt.dev.js.ast.JsVisitor;
import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.ast.Argument;
import org.eclipse.jdt.internal.compiler.ast.MethodDeclaration;
import org.eclipse.jdt.internal.compiler.lookup.ClassScope;
import java.io.IOException;
import java.io.StringReader;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
/**
* Walks the AST to find references to Java identifiers from within JSNI blocks.
* By default, it does a full JavaScript parse to accurately find JSNI
* references. If {@link #beSloppy()} is called, then it will run much more
* quickly but it will return a superset of the actual JSNI references.
*/
public class FindJsniRefVisitor extends ASTVisitor {
private final Set<String> jsniRefs = new LinkedHashSet<String>();
public Set<String> getJsniRefs() {
return Collections.unmodifiableSet(jsniRefs);
}
public boolean visit(MethodDeclaration methodDeclaration, ClassScope scope) {
if (!methodDeclaration.isNative()) {
return false;
}
// Handle JSNI block
String jsniCode = getJSNICode(methodDeclaration);
if (jsniCode == null) {
return false;
}
if (jsniCode.indexOf('@') < 0) {
// short cut: if there are no at signs, there are no JSNI refs
return false;
}
findJsniRefsAccurately(methodDeclaration, jsniCode);
return false;
}
private void findJsniRefsAccurately(MethodDeclaration methodDeclaration,
String jsniCode) throws InternalCompilerException {
JsProgram jsProgram = new JsProgram();
String syntheticFnHeader = "function(";
boolean first = true;
if (methodDeclaration.arguments != null) {
for (int i = 0, c = methodDeclaration.arguments.length; i < c; ++i) {
Argument arg = methodDeclaration.arguments[i];
if (first) {
first = false;
} else {
syntheticFnHeader += ',';
}
syntheticFnHeader += String.valueOf(arg.name);
}
}
syntheticFnHeader += ')';
StringReader sr = new StringReader(syntheticFnHeader + '\n' + jsniCode);
try {
// start at -1 to avoid counting our synthetic header
List<JsStatement> result = JsParser.parse(SourceOrigin.UNKNOWN,
jsProgram.getScope(), sr);
new JsVisitor() {
public void endVisit(JsNameRef x, JsContext<JsExpression> ctx) {
String ident = x.getIdent();
if (ident.charAt(0) == '@') {
jsniRefs.add(ident.substring(1));
}
}
}.acceptList(result);
} catch (IOException e) {
throw new InternalCompilerException(e.getMessage(), e);
} catch (JsParserException e) {
// ignore, we only care about finding valid references
}
}
private String getJSNICode(MethodDeclaration methodDeclaration) {
char[] source = methodDeclaration.compilationResult().getCompilationUnit().getContents();
String jsniCode = String.valueOf(source, methodDeclaration.bodyStart,
methodDeclaration.bodyEnd - methodDeclaration.bodyStart + 1);
int startPos = jsniCode.indexOf(JsniCollector.JSNI_BLOCK_START);
int endPos = jsniCode.lastIndexOf(JsniCollector.JSNI_BLOCK_END);
if (startPos < 0 || endPos < 0) {
return null; // ignore the error
}
startPos += JsniCollector.JSNI_BLOCK_START.length() - 1; // move up to open brace
endPos += 1; // move past close brace
jsniCode = jsniCode.substring(startPos, endPos);
return jsniCode;
}
}