/*
* Copyright 2011 The Closure Compiler Authors.
*
* 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.javascript.jscomp;
import com.google.common.collect.Lists;
import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.Token;
import java.util.List;
/**
* <p>Compiler pass that converts all calls to:
* goog.object.create(key1, val1, key2, val2, ...) where all of the keys
* are literals into object literals.</p>
*
* @author agrieve@google.com (Andrew Grieve)
*/
final class ClosureOptimizePrimitives implements CompilerPass {
/** Reference to the JS compiler */
private final AbstractCompiler compiler;
/**
* Identifies all calls to goog.object.create.
*/
private static class FindObjectCreateCalls extends AbstractPostOrderCallback {
List<Node> callNodes = Lists.newArrayList();
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
if (n.isCall()) {
Node fn = n.getFirstChild();
if (fn.matchesQualifiedName("goog$object$create") ||
fn.matchesQualifiedName("goog.object.create")) {
callNodes.add(n);
}
}
}
}
/**
* @param compiler The AbstractCompiler
*/
ClosureOptimizePrimitives(AbstractCompiler compiler) {
this.compiler = compiler;
}
@Override
public void process(Node externs, Node root) {
FindObjectCreateCalls pass = new FindObjectCreateCalls();
NodeTraversal.traverse(compiler, root, pass);
processObjectCreateCalls(pass.callNodes);
}
/**
* Converts all of the given call nodes to object literals that are safe to
* do so.
*/
private void processObjectCreateCalls(List<Node> callNodes) {
for (Node callNode : callNodes) {
Node curParam = callNode.getFirstChild().getNext();
if (canOptimizeObjectCreate(curParam)) {
Node objNode = IR.objectlit().srcref(callNode);
while (curParam != null) {
Node keyNode = curParam;
Node valueNode = curParam.getNext();
curParam = valueNode.getNext();
callNode.removeChild(keyNode);
callNode.removeChild(valueNode);
if (!keyNode.isString()) {
keyNode = IR.string(NodeUtil.getStringValue(keyNode))
.srcref(keyNode);
}
keyNode.setType(Token.STRING_KEY);
keyNode.setQuotedString();
objNode.addChildToBack(IR.propdef(keyNode, valueNode));
}
callNode.getParent().replaceChild(callNode, objNode);
compiler.reportCodeChange();
}
}
}
/**
* Returns whether the given call to goog.object.create can be converted to an
* object literal.
*/
private static boolean canOptimizeObjectCreate(Node firstParam) {
Node curParam = firstParam;
while (curParam != null) {
// All keys must be strings or numbers.
if (!curParam.isString() && !curParam.isNumber()) {
return false;
}
curParam = curParam.getNext();
// Check for an odd number of parameters.
if (curParam == null) {
return false;
}
curParam = curParam.getNext();
}
return true;
}
}