/**
* 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.EvaluatingDocOpCursor;
import org.waveprotocol.wave.model.document.operation.algorithm.RangeNormalizer;
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;
/**
* A utility class for transforming an insertion operation with a deletion operation.
*
* @author Alexandre Mah
*/
final class InsertionDeletionTransformer {
/**
* 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 resolve(int retain);
}
/**
* 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 static abstract class Target implements EvaluatingDocOpCursor<DocOp> {
/**
* The target to which to write the transformed mutation.
*/
final EvaluatingDocOpCursor<DocOp> targetDocument =
new RangeNormalizer<DocOp>(new DocOpBuffer());
/**
* 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.
*/
final RelativePosition relativePosition;
Target(RelativePosition relativePosition) {
this.relativePosition = relativePosition;
}
@Override
public DocOp finish() {
return targetDocument.finish();
}
}
private static final class InsertionTarget extends Target {
NoninsertionTarget otherTarget;
InsertionTarget(RelativePosition relativePosition) {
super(relativePosition);
}
public void setOtherTarget(NoninsertionTarget otherTarget) {
this.otherTarget = otherTarget;
}
@Override
public void retain(int itemCount) {
int oldPosition = relativePosition.get();
relativePosition.increase(itemCount);
if (relativePosition.get() < 0) {
otherTarget.rangeCache.resolve(itemCount);
} else if (oldPosition < 0) {
otherTarget.rangeCache.resolve(-oldPosition);
}
}
@Override
public void characters(String chars) {
if (otherTarget.depth > 0) {
otherTarget.targetDocument.deleteCharacters(chars);
} else {
targetDocument.characters(chars);
otherTarget.targetDocument.retain(chars.length());
}
}
@Override
public void elementStart(String tag, Attributes attrs) {
if (otherTarget.depth > 0) {
otherTarget.targetDocument.deleteElementStart(tag, attrs);
} else {
targetDocument.elementStart(tag, attrs);
otherTarget.targetDocument.retain(1);
}
}
@Override
public void elementEnd() {
if (otherTarget.depth > 0) {
otherTarget.targetDocument.deleteElementEnd();
} else {
targetDocument.elementEnd();
otherTarget.targetDocument.retain(1);
}
}
@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) {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void updateAttributes(AttributesUpdate attrUpdate) {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void annotationBoundary(AnnotationBoundaryMap map) {
throw new UnsupportedOperationException("This method should never be called.");
}
}
private static final class NoninsertionTarget extends Target {
private final class DeleteCharactersCache extends RangeCache {
private String characters;
DeleteCharactersCache(String characters) {
this.characters = characters;
}
@Override
void resolve(int itemCount) {
targetDocument.deleteCharacters(characters.substring(0, itemCount));
characters = characters.substring(itemCount);
}
}
private final class DeleteElementStartCache extends RangeCache {
private final String type;
private final Attributes attributes;
DeleteElementStartCache(String type, Attributes attributes) {
this.type = type;
this.attributes = attributes;
}
@Override
void resolve(int itemCount) {
targetDocument.deleteElementStart(type, attributes);
++depth;
}
}
private final RangeCache retainCache = new RangeCache() {
@Override
void resolve(int itemCount) {
targetDocument.retain(itemCount);
otherTarget.targetDocument.retain(itemCount);
}
};
private final RangeCache deleteElementEndCache = new RangeCache() {
@Override
void resolve(int itemCount) {
targetDocument.deleteElementEnd();
--depth;
}
};
/**
* A cache for the effect of mutation components which affect ranges.
*/
private RangeCache rangeCache = retainCache;
/**
* The current depth of element deletions.
*/
private int depth = 0;
private InsertionTarget otherTarget;
NoninsertionTarget(RelativePosition relativePosition) {
super(relativePosition);
}
public void setOtherTarget(InsertionTarget otherTarget) {
this.otherTarget = otherTarget;
}
@Override
public void retain(int itemCount) {
resolveRange(itemCount, retainCache);
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) {
RangeCache cache = new DeleteCharactersCache(chars);
int resolutionSize = resolveRange(chars.length(), cache);
if (resolutionSize >= 0) {
rangeCache = cache;
}
}
@Override
public void deleteElementStart(String tag, Attributes attrs) {
RangeCache cache = new DeleteElementStartCache(tag, attrs);
if (resolveRange(1, cache) == 0) {
rangeCache = cache;
}
}
@Override
public void deleteElementEnd() {
if (resolveRange(1, deleteElementEndCache) == 0) {
rangeCache = deleteElementEndCache;
}
}
@Override
public void replaceAttributes(Attributes oldAttrs, Attributes newAttrs) {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void updateAttributes(AttributesUpdate attrUpdate) {
throw new UnsupportedOperationException("This method should never be called.");
}
@Override
public void annotationBoundary(AnnotationBoundaryMap map) {
throw new UnsupportedOperationException("This method should never be called.");
}
/**
* Resolves the transformation of a range.
*
* @param size the requested size to resolve
* @param cache the cache 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, RangeCache cache) {
int oldPosition = relativePosition.get();
relativePosition.increase(size);
if (relativePosition.get() > 0) {
if (oldPosition < 0) {
cache.resolve(-oldPosition);
}
return -oldPosition;
} else {
cache.resolve(size);
return -1;
}
}
}
/**
* Transforms an insertion operation with a deletion operation.
*
* @param insertionOp the insertion operation
* @param deletionOp the deletion operation
* @return the transformed pair of operations
* @throws TransformException if a problem was encountered during the
* transformation process
*/
OperationPair<DocOp> transformOperations(DocOp insertionOp,
DocOp deletionOp) throws TransformException {
PositionTracker positionTracker = new PositionTracker();
RelativePosition insertionPosition = positionTracker.getPosition1();
RelativePosition deletionPosition = positionTracker.getPosition2();
// The target responsible for processing components of the insertion operation.
InsertionTarget insertionTarget = new InsertionTarget(insertionPosition);
// The target responsible for processing components of the deletion operation.
NoninsertionTarget deletionTarget = new NoninsertionTarget(deletionPosition);
insertionTarget.setOtherTarget(deletionTarget);
deletionTarget.setOtherTarget(insertionTarget);
// Incrementally apply the two operations in a linearly-ordered interleaving
// fashion.
int insertionIndex = 0;
int deletionIndex = 0;
while (insertionIndex < insertionOp.size()) {
insertionOp.applyComponent(insertionIndex++, insertionTarget);
while (insertionPosition.get() > 0) {
if (deletionIndex >= deletionOp.size()) {
throw new TransformException("Ran out of " + deletionOp.size()
+ " deletion op components after " + insertionIndex + " of " + insertionOp.size()
+ " insertion op components, with " + insertionPosition.get() + " spare positions");
}
deletionOp.applyComponent(deletionIndex++, deletionTarget);
}
}
while (deletionIndex < deletionOp.size()) {
deletionOp.applyComponent(deletionIndex++, deletionTarget);
}
insertionOp = insertionTarget.finish();
deletionOp = deletionTarget.finish();
return new OperationPair<DocOp>(insertionOp, deletionOp);
}
}