/**
* Copyright 2010 Google Inc.
*
* 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 org.waveprotocol.wave.model.operation.testing.reference;
import org.waveprotocol.wave.model.document.operation.AnnotationBoundaryMap;
import org.waveprotocol.wave.model.document.operation.Attributes;
import org.waveprotocol.wave.model.document.operation.AttributesUpdate;
import org.waveprotocol.wave.model.document.operation.DocOp;
import org.waveprotocol.wave.model.document.operation.DocOpCursor;
import org.waveprotocol.wave.model.document.operation.EvaluatingDocOpCursor;
import org.waveprotocol.wave.model.document.operation.algorithm.OperationNormalizer;
import org.waveprotocol.wave.model.document.operation.impl.AnnotationBoundaryMapImpl;
import org.waveprotocol.wave.model.document.operation.impl.AttributesUpdateImpl;
import org.waveprotocol.wave.model.document.operation.impl.DocOpBuffer;
import org.waveprotocol.wave.model.operation.OperationPair;
import org.waveprotocol.wave.model.operation.TransformException;
import org.waveprotocol.wave.model.operation.testing.reference.PositionTracker.RelativePosition;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* A utility class for transforming structure-preserving operations.
*
* @author Alexandre Mah
*/
final class PreservationPreservationTransformer {
/**
* For internal error propagation. It is a RuntimeException to facilitate
* error propagation through document operation interfaces from outside
* this package.
*/
private static class InternalTransformException extends RuntimeException {
InternalTransformException(String message) {
super(message);
}
}
private abstract class AnnotationTracker {
// NOTE: The following can be made more efficient with a more specialized data structure.
final Map<String, ValueUpdate> tracked = new HashMap<String, ValueUpdate>();
final DocOpCursor output;
AnnotationTracker(DocOpCursor output) {
this.output = output;
}
void register(AnnotationBoundaryMap map) {
for (int i = 0; i < map.endSize(); ++i) {
tracked.remove(map.getEndKey(i));
}
for (int i = 0; i < map.changeSize(); ++i) {
tracked.put(map.getChangeKey(i), new ValueUpdate(map.getOldValue(i), map.getNewValue(i)));
}
process(map);
}
abstract void process(AnnotationBoundaryMap map);
}
/**
* A cache for the effect of a component of a document mutation that affects a
* range of the document.
*/
private static abstract class RangeCache {
abstract void resolveRetain(int retain);
void resolveReplaceAttributes(Attributes oldAttributes, Attributes newAttributes) {
throw new InternalTransformException("Incompatible operations in transformation");
}
void resolveUpdateAttributes(AttributesUpdate update) {
throw new InternalTransformException("Incompatible operations in transformation");
}
}
/**
* A resolver for mutation components which affects ranges.
*/
private interface RangeResolver {
/**
* Resolves a mutation component with a cached mutation component from a
* different document mutation.
*
* @param size The size of the range affected by the range modifications to
* resolve.
* @param cache The cached range.
*/
void resolve(int size, RangeCache cache);
}
/**
* A resolver for "replaceAttributes" mutation components.
*/
private static final class ReplaceAttributesResolver implements RangeResolver {
private final Attributes oldAttributes;
private final Attributes newAttributes;
ReplaceAttributesResolver(Attributes oldAttributes, Attributes newAttributes) {
this.oldAttributes = oldAttributes;
this.newAttributes = newAttributes;
}
@Override
public void resolve(int size, RangeCache range) {
range.resolveReplaceAttributes(oldAttributes, newAttributes);
}
}
/**
* A resolver for "updateAttributes" mutation components.
*/
private static final class UpdateAttributesResolver implements RangeResolver {
private final AttributesUpdate update;
UpdateAttributesResolver(AttributesUpdate update) {
this.update = update;
}
@Override
public void resolve(int size, RangeCache range) {
range.resolveUpdateAttributes(update);
}
}
/**
* A resolver for "retain" mutation components.
*/
private static final RangeResolver RETAIN_RESOLVER = new RangeResolver() {
@Override
public void resolve(int size, RangeCache range) {
range.resolveRetain(size);
}
};
/**
* A target of a document mutation which can be used to transform document
* mutations by making use primarily of information from one mutation with the
* help of auxiliary information from a second mutation. These targets should
* be used in pairs.
*/
private final class Target implements EvaluatingDocOpCursor<DocOp> {
private final class ReplaceAttributesCache extends RangeCache {
private final Attributes oldAttributes;
private final Attributes newAttributes;
ReplaceAttributesCache(Attributes oldAttributes, Attributes newAttributes) {
this.oldAttributes = oldAttributes;
this.newAttributes = newAttributes;
}
@Override
void resolveRetain(int itemCount) {
targetDocument.replaceAttributes(oldAttributes, newAttributes);
otherTarget.targetDocument.retain(1);
}
@Override
void resolveReplaceAttributes(Attributes oldAttributes, Attributes newAttributes) {
targetDocument.replaceAttributes(newAttributes, this.newAttributes);
otherTarget.targetDocument.retain(1);
}
@Override
void resolveUpdateAttributes(AttributesUpdate update) {
targetDocument.replaceAttributes(this.oldAttributes.updateWith(update), this.newAttributes);
otherTarget.targetDocument.retain(1);
}
}
private final class UpdateAttributesCache extends RangeCache {
private final AttributesUpdate update;
UpdateAttributesCache(AttributesUpdate update) {
this.update = update;
}
@Override
void resolveRetain(int itemCount) {
targetDocument.updateAttributes(update);
otherTarget.targetDocument.retain(1);
}
@Override
void resolveReplaceAttributes(Attributes oldAttributes, Attributes newAttributes) {
targetDocument.retain(1);
otherTarget.targetDocument.replaceAttributes(oldAttributes.updateWith(update),
newAttributes);
}
@Override
void resolveUpdateAttributes(AttributesUpdate update) {
Map<String, String> updated = new HashMap<String, String>();
for (int i = 0; i < update.changeSize(); ++i) {
updated.put(update.getChangeKey(i), update.getNewValue(i));
}
AttributesUpdate newUpdate = new AttributesUpdateImpl();
// TODO: This is a little silly. We should do this a better way.
for (int i = 0; i < this.update.changeSize(); ++i) {
String key = this.update.getChangeKey(i);
String newOldValue = updated.containsKey(key) ? updated.get(key)
: this.update.getOldValue(i);
newUpdate = newUpdate.composeWith(new AttributesUpdateImpl(key,
newOldValue, this.update.getNewValue(i)));
}
targetDocument.updateAttributes(newUpdate);
Set<String> keySet = new HashSet<String>();
for (int i = 0; i < this.update.changeSize(); ++i) {
keySet.add(this.update.getChangeKey(i));
}
AttributesUpdate transformedAttributes = update.exclude(keySet);
otherTarget.targetDocument.updateAttributes(transformedAttributes);
}
}
private final RangeCache retainCache = new RangeCache() {
@Override
void resolveRetain(int itemCount) {
targetDocument.retain(itemCount);
otherTarget.targetDocument.retain(itemCount);
}
@Override
void resolveReplaceAttributes(Attributes oldAttributes, Attributes newAttributes) {
targetDocument.retain(1);
otherTarget.targetDocument.replaceAttributes(oldAttributes, newAttributes);
}
@Override
void resolveUpdateAttributes(AttributesUpdate update) {
targetDocument.retain(1);
otherTarget.targetDocument.updateAttributes(update);
}
};
/**
* The target to which to write the transformed mutation.
*/
private final EvaluatingDocOpCursor<DocOp> targetDocument;
/**
* The position of the processing cursor associated with this target
* relative to the position of the processing cursor associated to the
* opposing target. All positional calculations are based on cursor
* positions in the original document on which the two original operations
* apply.
*/
private final RelativePosition relativePosition;
/**
* An annotation tracker that tracks annotation modifications at the current
* cursor position.
*/
private final AnnotationTracker annotationTracker;
/**
* The target that is used opposite this target in the transformation.
*/
private Target otherTarget;
/**
* A cache for the effect of mutation components which affect ranges.
*/
private RangeCache rangeCache = retainCache;
Target(EvaluatingDocOpCursor<DocOp> targetDocument, RelativePosition relativePosition,
AnnotationTracker annotationTracker) {
this.targetDocument = targetDocument;
this.relativePosition = relativePosition;
this.annotationTracker = annotationTracker;
}
// TODO: See if we can remove this explicit method and find a
// better way to do this using a constructor or factory.
public void setOtherTarget(Target otherTarget) {
this.otherTarget = otherTarget;
}
@Override
public DocOp finish() {
return targetDocument.finish();
}
@Override
public void retain(int itemCount) {
resolveRange(itemCount, RETAIN_RESOLVER);
rangeCache = retainCache;
}
@Override
public void characters(String chars) {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void elementStart(String tag, Attributes attrs) {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void elementEnd() {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void deleteCharacters(String chars) {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void deleteElementStart(String tag, Attributes attrs) {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void deleteElementEnd() {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void replaceAttributes(Attributes oldAttrs, Attributes newAttrs) {
if (resolveRange(1, new ReplaceAttributesResolver(oldAttrs, newAttrs)) == 0) {
rangeCache = new ReplaceAttributesCache(oldAttrs, newAttrs);
}
}
@Override
public void updateAttributes(AttributesUpdate attrUpdate) {
if (resolveRange(1, new UpdateAttributesResolver(attrUpdate)) == 0) {
rangeCache = new UpdateAttributesCache(attrUpdate);
}
}
@Override
public void annotationBoundary(AnnotationBoundaryMap map) {
annotationTracker.register(map);
}
/**
* Resolves the transformation of a range.
*
* @param size the requested size to resolve
* @param resolver the resolver to use
* @return the portion of the requested size that was resolved, or -1 to
* indicate that the entire range was resolved
*/
private int resolveRange(int size, RangeResolver resolver) {
int oldPosition = relativePosition.get();
relativePosition.increase(size);
if (relativePosition.get() > 0) {
if (oldPosition < 0) {
resolver.resolve(-oldPosition, otherTarget.rangeCache);
}
return -oldPosition;
} else {
resolver.resolve(size, otherTarget.rangeCache);
return -1;
}
}
}
private final EvaluatingDocOpCursor<DocOp> clientOperation =
OperationNormalizer.createNormalizer(new DocOpBuffer());
private final EvaluatingDocOpCursor<DocOp> serverOperation =
OperationNormalizer.createNormalizer(new DocOpBuffer());
private final AnnotationTracker clientAnnotationTracker =
new AnnotationTracker(clientOperation) {
@Override
public void process(AnnotationBoundaryMap map) {
// TODO: This seems pretty awkward. Perhaps we should give
// AnnotationBoundaryMapImpl an easier builder to use. Perhaps try
// AnnotationBoundaryMapBuilder.
List<String> clientEndKeys = new ArrayList<String>();
List<String> clientChangeKeys = new ArrayList<String>();
List<String> clientChangeOldValues = new ArrayList<String>();
List<String> clientChangeNewValues = new ArrayList<String>();
List<String> serverEndKeys = new ArrayList<String>();
List<String> serverChangeKeys = new ArrayList<String>();
List<String> serverChangeOldValues = new ArrayList<String>();
List<String> serverChangeNewValues = new ArrayList<String>();
for (int i = 0; i < map.endSize(); ++i) {
String key = map.getEndKey(i);
ValueUpdate serverValues = serverAnnotationTracker.tracked.get(key);
clientEndKeys.add(key);
if (serverValues != null) {
serverChangeKeys.add(key);
serverChangeOldValues.add(serverValues.oldValue);
serverChangeNewValues.add(serverValues.newValue);
}
}
for (int i = 0; i < map.changeSize(); ++i) {
String key = map.getChangeKey(i);
String oldValue = map.getOldValue(i);
String newValue = map.getNewValue(i);
ValueUpdate serverValues = serverAnnotationTracker.tracked.get(key);
clientChangeKeys.add(key);
clientChangeNewValues.add(newValue);
if (serverValues != null) {
clientChangeOldValues.add(serverValues.newValue);
serverEndKeys.add(key);
} else {
clientChangeOldValues.add(oldValue);
}
}
output.annotationBoundary(new AnnotationBoundaryMapImpl(
clientEndKeys.toArray(new String[0]),
clientChangeKeys.toArray(new String[0]),
clientChangeOldValues.toArray(new String[0]),
clientChangeNewValues.toArray(new String[0])));
serverAnnotationTracker.output.annotationBoundary(new AnnotationBoundaryMapImpl(
serverEndKeys.toArray(new String[0]),
serverChangeKeys.toArray(new String[0]),
serverChangeOldValues.toArray(new String[0]),
serverChangeNewValues.toArray(new String[0])));
}
};
private final AnnotationTracker serverAnnotationTracker =
new AnnotationTracker(serverOperation) {
@Override
public void process(AnnotationBoundaryMap map) {
// TODO: This seems pretty awkward. Perhaps we should give
// AnnotationBoundaryMapImpl an easier builder to use.
List<String> serverEndKeys = new ArrayList<String>();
List<String> serverChangeKeys = new ArrayList<String>();
List<String> serverChangeOldValues = new ArrayList<String>();
List<String> serverChangeNewValues = new ArrayList<String>();
List<String> clientEndKeys = new ArrayList<String>();
List<String> clientChangeKeys = new ArrayList<String>();
List<String> clientChangeOldValues = new ArrayList<String>();
List<String> clientChangeNewValues = new ArrayList<String>();
for (int i = 0; i < map.endSize(); ++i) {
String key = map.getEndKey(i);
ValueUpdate clientValues = clientAnnotationTracker.tracked.get(key);
if (clientValues != null) {
clientChangeKeys.add(key);
clientChangeOldValues.add(clientValues.oldValue);
clientChangeNewValues.add(clientValues.newValue);
} else {
serverEndKeys.add(key);
}
}
for (int i = 0; i < map.changeSize(); ++i) {
String key = map.getChangeKey(i);
String oldValue = map.getOldValue(i);
String newValue = map.getNewValue(i);
ValueUpdate clientValues = clientAnnotationTracker.tracked.get(key);
if (clientValues != null) {
clientChangeKeys.add(key);
clientChangeOldValues.add(newValue);
clientChangeNewValues.add(clientValues.newValue);
} else {
serverChangeKeys.add(key);
serverChangeOldValues.add(oldValue);
serverChangeNewValues.add(newValue);
}
}
output.annotationBoundary(new AnnotationBoundaryMapImpl(
serverEndKeys.toArray(new String[0]),
serverChangeKeys.toArray(new String[0]),
serverChangeOldValues.toArray(new String[0]),
serverChangeNewValues.toArray(new String[0])));
clientAnnotationTracker.output.annotationBoundary(new AnnotationBoundaryMapImpl(
clientEndKeys.toArray(new String[0]),
clientChangeKeys.toArray(new String[0]),
clientChangeOldValues.toArray(new String[0]),
clientChangeNewValues.toArray(new String[0])));
}
};
/**
* Transforms a pair of structure-preserving operations.
*
* @param clientOp the operation from the client
* @param serverOp the operation from the server
* @return the transformed pair of operations
* @throws TransformException if a problem was encountered during the
* transformation process
*/
OperationPair<DocOp> transformOperations(DocOp clientOp,
DocOp serverOp) throws TransformException {
try {
PositionTracker positionTracker = new PositionTracker();
RelativePosition clientPosition = positionTracker.getPosition1();
RelativePosition serverPosition = positionTracker.getPosition2();
// The target responsible for processing components of the client operation.
Target clientTarget = new Target(clientOperation, clientPosition, clientAnnotationTracker);
// The target responsible for processing components of the server operation.
Target serverTarget = new Target(serverOperation, serverPosition, serverAnnotationTracker);
clientTarget.setOtherTarget(serverTarget);
serverTarget.setOtherTarget(clientTarget);
// Incrementally apply the two operations in a linearly-ordered interleaving
// fashion.
int clientIndex = 0;
int serverIndex = 0;
while (clientIndex < clientOp.size()) {
clientOp.applyComponent(clientIndex++, clientTarget);
while (clientPosition.get() > 0) {
if (serverIndex >= serverOp.size()) {
throw new TransformException("Ran out of " + serverOp.size()
+ " server op components after " + clientIndex + " of " + clientOp.size()
+ " client op components, with " + clientPosition.get() + " spare positions");
}
serverOp.applyComponent(serverIndex++, serverTarget);
}
}
while (serverIndex < serverOp.size()) {
serverOp.applyComponent(serverIndex++, serverTarget);
}
clientOp = clientTarget.finish();
serverOp = serverTarget.finish();
} catch (InternalTransformException e) {
throw new TransformException(e.getMessage());
}
return new OperationPair<DocOp>(clientOp, serverOp);
}
}