/*
* 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.checkNotNull;
import static java.util.logging.Level.SEVERE;
import com.google.auto.value.AutoValue;
import com.google.common.base.CharMatcher;
import com.google.common.base.Function;
import com.google.common.base.Optional;
import com.google.common.collect.ImmutableClassToInstanceMap;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.errorprone.fixes.Fix;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.refaster.UStatement.UnifierWithUnconsumedStatements;
import com.google.errorprone.refaster.annotation.UseImportPolicy;
import com.sun.source.tree.StatementTree;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.Warner;
import java.io.IOException;
import java.io.StringWriter;
import java.lang.annotation.Annotation;
import java.util.Map;
import java.util.logging.Logger;
/**
* Template representing a sequence of consecutive statements.
*
* @author lowasser@google.com (Louis Wasserman)
*/
@AutoValue
public abstract class BlockTemplate extends Template<BlockTemplateMatch> {
private static final Logger logger = Logger.getLogger(BlockTemplate.class.toString());
public static BlockTemplate create(UStatement... templateStatements) {
return create(ImmutableMap.<String, UType>of(), templateStatements);
}
public static BlockTemplate create(Map<String, ? extends UType> expressionArgumentTypes,
UStatement... templateStatements) {
return create(ImmutableList.<UTypeVar>of(), expressionArgumentTypes, templateStatements);
}
public static BlockTemplate create(Iterable<UTypeVar> typeVariables,
Map<String, ? extends UType> expressionArgumentTypes, UStatement... templateStatements) {
return create(ImmutableClassToInstanceMap.<Annotation>builder().build(), typeVariables,
expressionArgumentTypes, ImmutableList.copyOf(templateStatements));
}
public static BlockTemplate create(ImmutableClassToInstanceMap<Annotation> annotations,
Iterable<UTypeVar> typeVariables, Map<String, ? extends UType> expressionArgumentTypes,
Iterable<? extends UStatement> templateStatements) {
return new AutoValue_BlockTemplate(annotations, ImmutableList.copyOf(typeVariables),
ImmutableMap.copyOf(expressionArgumentTypes), ImmutableList.copyOf(templateStatements));
}
public BlockTemplate withStatements(Iterable<? extends UStatement> templateStatements) {
return create(
annotations(), templateTypeVariables(), expressionArgumentTypes(), templateStatements);
}
abstract ImmutableList<UStatement> templateStatements();
/**
* If the tree is a {@link JCBlock}, returns a list of disjoint matches corresponding to the exact
* list of template statements found consecutively; otherwise, returns an empty list.
*/
@Override
public Iterable<BlockTemplateMatch> match(JCTree tree, Context context) {
// TODO(lowasser): consider nonconsecutive matches?
if (tree instanceof JCBlock) {
JCBlock block = (JCBlock) tree;
ImmutableList<JCStatement> targetStatements = ImmutableList.copyOf(block.getStatements());
return matchesStartingAnywhere(block, 0, targetStatements, context).first()
.or(List.<BlockTemplateMatch>nil());
}
return ImmutableList.of();
}
private Choice<List<BlockTemplateMatch>> matchesStartingAtBeginning(
final JCBlock block,
final int offset,
final ImmutableList<? extends StatementTree> statements,
final Context context) {
if (statements.isEmpty()) {
return Choice.none();
}
final JCStatement firstStatement = (JCStatement) statements.get(0);
Choice<UnifierWithUnconsumedStatements> choice =
Choice.of(UnifierWithUnconsumedStatements.create(new Unifier(context), statements));
for (UStatement templateStatement : templateStatements()) {
choice = choice.thenChoose(templateStatement);
}
return choice.thenChoose(
new Function<UnifierWithUnconsumedStatements, Choice<List<BlockTemplateMatch>>>() {
@Override
public Choice<List<BlockTemplateMatch>> apply(UnifierWithUnconsumedStatements state) {
Unifier unifier = state.unifier();
Inliner inliner = unifier.createInliner();
try {
Optional<Unifier> checkedUnifier = typecheck(unifier, inliner,
new Warner(firstStatement), expectedTypes(inliner), actualTypes(inliner));
if (checkedUnifier.isPresent()) {
int consumedStatements = statements.size() - state.unconsumedStatements().size();
BlockTemplateMatch match = new BlockTemplateMatch(block, checkedUnifier.get(),
offset, offset + consumedStatements);
return matchesStartingAnywhere(block, offset + consumedStatements,
statements.subList(consumedStatements, statements.size()), context).transform(
prepend(match));
}
} catch (CouldNotResolveImportException e) {
// fall through
}
return Choice.none();
}
});
}
private static <T> Function<List<T>, List<T>> prepend(final T t) {
return new Function<List<T>, List<T>>() {
@Override
public List<T> apply(List<T> list) {
return list.prepend(t);
}
};
}
private Choice<List<BlockTemplateMatch>> matchesStartingAnywhere(
JCBlock block,
int offset,
final ImmutableList<? extends StatementTree> statements,
final Context context) {
Choice<List<BlockTemplateMatch>> choice = Choice.none();
for (int i = 0; i < statements.size(); i++) {
choice = choice.or(matchesStartingAtBeginning(block, offset + i,
statements.subList(i, statements.size()), context));
}
return choice.or(Choice.of(List.<BlockTemplateMatch>nil()));
}
/**
* Returns a {@code String} representation of a statement, including semicolon.
*/
private static String printStatement(Context context, JCStatement statement) {
StringWriter writer = new StringWriter();
try {
pretty(context, writer).printStat(statement);
} catch (IOException e) {
throw new AssertionError("StringWriter cannot throw IOExceptions");
}
return writer.toString();
}
/**
* Returns a {@code String} representation of a sequence of statements, with semicolons and
* newlines.
*/
private static String printStatements(
Context context, Iterable<JCStatement> statements) {
StringWriter writer = new StringWriter();
try {
pretty(context, writer).printStats(com.sun.tools.javac.util.List.from(statements));
} catch (IOException e) {
throw new AssertionError("StringWriter cannot throw IOExceptions");
}
return writer.toString();
}
@Override
public Fix replace(BlockTemplateMatch match) {
checkNotNull(match);
SuggestedFix.Builder fix = SuggestedFix.builder();
Inliner inliner = match.createInliner();
Context context = inliner.getContext();
if (annotations().containsKey(UseImportPolicy.class)) {
ImportPolicy.bind(context, annotations().getInstance(UseImportPolicy.class).value());
} else {
ImportPolicy.bind(context, ImportPolicy.IMPORT_TOP_LEVEL);
}
ImmutableList<JCStatement> targetStatements = match.getStatements();
try {
ImmutableList.Builder<JCStatement> inlinedStatementsBuilder = ImmutableList.builder();
for (UStatement statement : templateStatements()) {
inlinedStatementsBuilder.addAll(statement.inlineStatements(inliner));
}
ImmutableList<JCStatement> inlinedStatements = inlinedStatementsBuilder.build();
int nInlined = inlinedStatements.size();
int nTargets = targetStatements.size();
if (nInlined <= nTargets) {
for (int i = 0; i < nInlined; i++) {
fix.replace(targetStatements.get(i),
printStatement(context, inlinedStatements.get(i)));
}
for (int i = nInlined; i < nTargets; i++) {
fix.delete(targetStatements.get(i));
}
} else {
for (int i = 0; i < nTargets - 1; i++) {
fix.replace(targetStatements.get(i),
printStatement(context, inlinedStatements.get(i)));
}
int last = nTargets - 1;
ImmutableList<JCStatement> remainingInlined =
inlinedStatements.subList(last, nInlined);
fix.replace(
targetStatements.get(last),
CharMatcher.whitespace().trimTrailingFrom(printStatements(context, remainingInlined)));
}
} catch (CouldNotResolveImportException e) {
logger.log(SEVERE, "Failure to resolve import in replacement", e);
}
return addImports(inliner, fix);
}
}