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/*
* Copyright 2000-2009 JetBrains s.r.o.
*
* 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.intellij.util.indexing;
import com.intellij.openapi.util.Computable;
import gnu.trove.TIntHashSet;
import gnu.trove.TIntProcedure;
import org.jetbrains.annotations.Nullable;
import java.util.Iterator;
import java.util.List;
/**
* @author Eugene Zhuravlev
* Date: Dec 20, 2007
*/
class ChangeTrackingValueContainer<Value> extends UpdatableValueContainer<Value>{
// there is no volatile as we modify under write lock and read under read lock
private ValueContainerImpl<Value> myAdded;
private TIntHashSet myInvalidated;
private volatile ValueContainerImpl<Value> myMerged;
private final Initializer<Value> myInitializer;
public interface Initializer<T> extends Computable<ValueContainer<T>> {
Object getLock();
}
public ChangeTrackingValueContainer(Initializer<Value> initializer) {
myInitializer = initializer;
}
@Override
public void addValue(int inputId, Value value) {
ValueContainerImpl<Value> merged = myMerged;
if (merged != null) {
merged.addValue(inputId, value);
}
if (myAdded == null) myAdded = new ValueContainerImpl<Value>();
myAdded.addValue(inputId, value);
}
@Override
public void removeAssociatedValue(int inputId) {
ValueContainerImpl<Value> merged = myMerged;
if (merged != null) {
merged.removeAssociatedValue(inputId);
}
if (myAdded != null) myAdded.removeAssociatedValue(inputId);
if (myInvalidated == null) myInvalidated = new TIntHashSet(1);
myInvalidated.add(inputId);
}
@Override
public int size() {
return getMergedData().size();
}
@Override
public Iterator<Value> getValueIterator() {
return getMergedData().getValueIterator();
}
@Override
public List<Value> toValueList() {
return getMergedData().toValueList();
}
@Override
public boolean isAssociated(final Value value, final int inputId) {
return getMergedData().isAssociated(value, inputId);
}
@Override
public IntPredicate getValueAssociationPredicate(Value value) {
return getMergedData().getValueAssociationPredicate(value);
}
@Override
public IntIterator getInputIdsIterator(final Value value) {
return getMergedData().getInputIdsIterator(value);
}
public void dropMergedData() {
myMerged = null;
}
// need 'synchronized' to ensure atomic initialization of merged data
// because several threads that acquired read lock may simultaneously execute the method
private ValueContainerImpl<Value> getMergedData() {
ValueContainerImpl<Value> merged = myMerged;
if (merged != null) {
return merged;
}
synchronized (myInitializer.getLock()) {
merged = myMerged;
if (merged != null) {
return merged;
}
final ValueContainer<Value> fromDisk = myInitializer.compute();
final ValueContainerImpl<Value> newMerged;
if (fromDisk instanceof ValueContainerImpl) {
newMerged = ((ValueContainerImpl<Value>)fromDisk).copy();
} else {
newMerged = ((ChangeTrackingValueContainer<Value>)fromDisk).getMergedData().copy();
}
if (myInvalidated != null) {
myInvalidated.forEach(new TIntProcedure() {
@Override
public boolean execute(int inputId) {
newMerged.removeAssociatedValue(inputId);
return true;
}
});
}
if (myAdded != null) {
myAdded.forEach(new ContainerAction<Value>() {
@Override
public boolean perform(final int id, final Value value) {
newMerged.removeAssociatedValue(id); // enforcing "one-value-per-file for particular key" invariant
newMerged.addValue(id, value);
return true;
}
});
}
setNeedsCompacting(fromDisk.needsCompacting());
myMerged = newMerged;
return newMerged;
}
}
public boolean isDirty() {
return (myAdded != null && myAdded.size() > 0) ||
(myInvalidated != null && !myInvalidated.isEmpty()) ||
needsCompacting();
}
public @Nullable ValueContainer<Value> getAddedDelta() {
return myAdded;
}
public @Nullable TIntHashSet getInvalidated() {
return myInvalidated;
}
}
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