/*
* Copyright 2013 Google Inc. All rights reserved.
*
* 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.errorprone.refaster;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.Iterables;
import com.sun.tools.javac.code.Symbol.PackageSymbol;
import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
import com.sun.tools.javac.tree.JCTree.JCImport;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.util.Context;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* Policy specifying when and how to import classes when inlining types.
*
* @author Louis Wasserman
*/
public enum ImportPolicy {
// TODO(lowasser): add support for other policies, like "explicitly qualify everything"
/**
* Import the outermost class and explicitly qualify references below that. For example, to
* reference {@code com.google.Foo.Bar}, we import {@code com.google.Foo} and explicitly qualify
* {@code Foo.Bar}.
*/
IMPORT_TOP_LEVEL {
@Override
public JCExpression classReference(
Inliner inliner, CharSequence topLevelClazz, CharSequence fullyQualifiedClazz) {
if (Refaster.class.getName().contentEquals(fullyQualifiedClazz)) {
// Special handling to ensure that the pretty-printer always recognizes Refaster references
return inliner.maker().Ident(inliner.asName("Refaster"));
}
List<String> allImports = getAllImports(inliner);
/*
* Check if topLevelClazz or fullyQualifiedClazz is already imported.
* If fullyQualifiedClazz is imported, return the class name.
* If topLevelClazz is imported, return the name from the top level class to the class name.
* If there are imports whose names conflict with topLevelClazz, return fully qualified name.
* Otherwise, import toplevelClazz, and return the name from the top level class
* to the class name.
*/
checkArgument(topLevelClazz.length() > 0 && fullyQualifiedClazz.length() > 0,
String.format(
"either topLevelClass (%s) or fullyQualifiedClazz (%s) is null or empty",
topLevelClazz,
fullyQualifiedClazz));
List<String> topLevelPath = Splitter.on('.').splitToList(topLevelClazz);
String topClazz = Iterables.getLast(topLevelPath);
List<String> qualifiedPath = Splitter.on('.').splitToList(fullyQualifiedClazz);
boolean importTopLevelClazz = false, conflictTopLevelClazz = false;
for (String importName : allImports) {
if (importName.contentEquals(fullyQualifiedClazz)) {
// fullyQualifiedClazz already imported
return makeSelectExpression(inliner, qualifiedPath, qualifiedPath.size() - 1);
}
importTopLevelClazz |= importName.contentEquals(topLevelClazz);
if (!importTopLevelClazz) {
conflictTopLevelClazz |= topClazz.equals(
Iterables.getLast(Splitter.on('.').split(importName)));
}
}
if (importTopLevelClazz) {
return makeSelectExpression(inliner, qualifiedPath, topLevelPath.size() - 1);
} else if (conflictTopLevelClazz) {
return makeSelectExpression(inliner, qualifiedPath, 0);
}
// No conflicts
String packge = Joiner.on('.').join(topLevelPath.subList(0, topLevelPath.size() - 1));
PackageSymbol currentPackage = inliner.getContext().get(PackageSymbol.class);
if (currentPackage == null || !currentPackage.getQualifiedName().contentEquals(packge)) {
// don't import classes from the same package as the class we're refactoring
inliner.addImport(topLevelClazz.toString());
}
return makeSelectExpression(inliner, qualifiedPath, topLevelPath.size() - 1);
}
@Override
public JCExpression staticReference(Inliner inliner, CharSequence topLevelClazz,
CharSequence fullyQualifiedClazz, CharSequence member) {
return inliner.maker().Select(
classReference(inliner, topLevelClazz, fullyQualifiedClazz), inliner.asName(member));
}
/* Returns a combined list of strings from importsInSource and importsToAdd. */
private List<String> getAllImports(Inliner inliner) {
List<String> allImports = new ArrayList<>(inliner.getImportsToAdd());
if (inliner.getContext() != null
&& inliner.getContext().get(JCCompilationUnit.class) != null) {
for (JCImport jcImport : inliner.getContext().get(JCCompilationUnit.class).getImports()) {
JCFieldAccess qualified = (JCFieldAccess) jcImport.getQualifiedIdentifier();
allImports.add(qualified.toString());
}
}
return allImports;
}
private JCExpression makeSelectExpression(
Inliner inliner, List<String> qualifiedPath, int start) {
Iterator<String> selects = qualifiedPath.listIterator(start);
TreeMaker maker = inliner.maker();
JCExpression select = maker.Ident(inliner.asName(selects.next()));
while (selects.hasNext()) {
select = maker.Select(select, inliner.asName(selects.next()));
}
return select;
}
},
/**
* Import nested classes directly, and qualify static references from the class level.
*/
IMPORT_CLASS_DIRECTLY {
@Override
public JCExpression classReference(Inliner inliner, CharSequence topLevelClazz,
CharSequence fullyQualifiedClazz) {
if (Refaster.class.getName().contentEquals(fullyQualifiedClazz)) {
// Special handling to ensure that the pretty-printer always recognizes Refaster references
return inliner.maker().Ident(inliner.asName("Refaster"));
}
String packge = topLevelClazz.toString();
int lastDot = packge.lastIndexOf('.');
packge = (lastDot >= 0) ? packge.substring(0, lastDot) : "";
PackageSymbol currentPackage = inliner.getContext().get(PackageSymbol.class);
if (currentPackage == null || !currentPackage.getQualifiedName().contentEquals(packge)
|| !topLevelClazz.equals(fullyQualifiedClazz)) {
// don't import classes from the same package as the class we're refactoring
inliner.addImport(fullyQualifiedClazz.toString());
}
String simpleName = fullyQualifiedClazz.toString();
simpleName = simpleName.substring(simpleName.lastIndexOf('.') + 1);
return inliner.maker().Ident(inliner.asName(simpleName));
}
@Override
public JCExpression staticReference(Inliner inliner, CharSequence topLevelClazz,
CharSequence fullyQualifiedClazz, CharSequence member) {
if (Refaster.class.getName().contentEquals(topLevelClazz)) {
// Special handling to ensure that the pretty-printer always recognizes Refaster references
return inliner
.maker()
.Select(inliner.maker().Ident(inliner.asName("Refaster")), inliner.asName(member));
}
return inliner.maker().Select(
classReference(inliner, topLevelClazz, fullyQualifiedClazz),
inliner.asName(member));
}
},
/**
* When inlining static methods, always static import the method. Non-static references to
* classes are imported from the top level as in {@code IMPORT_TOP_LEVEL}.
*/
STATIC_IMPORT_ALWAYS {
@Override
public JCExpression classReference(
Inliner inliner, CharSequence topLevelClazz, CharSequence fullyQualifiedClazz) {
return IMPORT_TOP_LEVEL.classReference(inliner, topLevelClazz, fullyQualifiedClazz);
}
@Override
public JCExpression staticReference(Inliner inliner, CharSequence topLevelClazz,
CharSequence fullyQualifiedClazz, CharSequence member) {
if (Refaster.class.getName().contentEquals(topLevelClazz)) {
// Special handling to ensure that the pretty-printer always recognizes Refaster references
return inliner
.maker()
.Select(inliner.maker().Ident(inliner.asName("Refaster")), inliner.asName(member));
}
inliner.addStaticImport(fullyQualifiedClazz + "." + member);
return inliner.maker().Ident(inliner.asName(member));
}
};
public static void bind(Context context, ImportPolicy policy) {
context.put(ImportPolicy.class, checkNotNull(policy));
}
public static ImportPolicy instance(Context context) {
ImportPolicy result = context.get(ImportPolicy.class);
checkState(result != null, "No ImportPolicy bound in this context");
return result;
}
public abstract JCExpression classReference(
Inliner inliner, CharSequence topLevelClazz, CharSequence fullyQualifiedClazz);
public abstract JCExpression staticReference(Inliner inliner, CharSequence topLevelClazz,
CharSequence fullyQualifiedClazz, CharSequence member);
}