com.google.javascript.jscomp.FieldCleanupPass Maven / Gradle / Ivy
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/*
* 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.javascript.jscomp.NodeTraversal.AbstractShallowCallback;
import com.google.javascript.jscomp.NodeTraversal.Callback;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.jstype.JSType;
import com.google.javascript.rhino.jstype.JSTypeRegistry;
import com.google.javascript.rhino.jstype.ObjectType;
/**
* A CleanupPass implementation that will remove all field declarations on
* JSTypes contributed by the original file.
*
* This pass is expected to clear out declarations contributed to any JSType,
* even if the constructor declaration is not provided in the file being
* updated.
*/
public final class FieldCleanupPass implements HotSwapCompilerPass {
private final AbstractCompiler compiler;
public FieldCleanupPass(AbstractCompiler compiler) {
this.compiler = compiler;
}
@Override
public void hotSwapScript(Node scriptRoot, Node originalRoot) {
String srcName = originalRoot.getSourceFileName();
Callback cb =
new QualifiedNameSearchTraversal(compiler.getTypeRegistry(), srcName);
NodeTraversal.traverse(compiler, originalRoot, cb);
}
@Override
public void process(Node externs, Node root) {
// FieldCleanupPass should not do work during process.
}
/**
* Search for fields to cleanup by looking for nodes in the tree which are
* root nodes of qualified names and getting the final token of the qualified
* name as a candidate field.
*
* Once a candidate field is found, ask the {@code JSTypeRegistry} for all
* JSTypes that have a field with the same name, and check if the field on
* that type is defined in the file the compiler is cleaning up. If so, remove
* the field, and update the {@code JSTypeRegistry} to no longer associate the
* type with the field.
*
* This algorithm was chosen for simplicity and is less than optimally
* efficient in two ways:
*
* 1) All types with a matching field name are iterated over (when only types
* that extend or implement the JSType indicated by the containing object in
* the found Qualified Name need to be checked).
*
* 2) All Qualified Names are checked, even those which are not L-Values or
* single declarations of an Type Expression. In general field should only be
* declared as part of an assignment ('ns.Type.a = 3;') or stand alone name
* declaration ('ns.Type.a;').
*/
static class QualifiedNameSearchTraversal extends AbstractShallowCallback {
private final JSTypeRegistry typeRegistry;
private final String srcName;
public QualifiedNameSearchTraversal(
JSTypeRegistry typeRegistry, String srcName) {
this.typeRegistry = typeRegistry;
this.srcName = srcName;
}
@Override
public void visit(NodeTraversal t, Node n, Node p) {
// We are a root GetProp
if (n.isGetProp() && !p.isGetProp()) {
String propName = getFieldName(n);
JSType type = n.getFirstChild().getJSType();
if (type == null || type.toObjectType() == null) {
// Note cases like .field
return;
}
removeProperty(type.toObjectType(), propName);
}
}
/**
* Removes a given property from a type and updates type-registry.
*
* @param type the object type to be updated, should not be null
* @param propName the property to remove
*/
private void removeProperty(ObjectType type, String propName) {
Node pNode = type.getPropertyNode(propName);
if (pNode != null && srcName.equals(pNode.getSourceFileName())) {
typeRegistry.unregisterPropertyOnType(propName, type);
type.removeProperty(propName);
}
}
private static String getFieldName(Node n) {
return n.getLastChild().getString();
}
}
}