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-rw-r--r--plugins/org.eclipse.emf.compare/src/org/eclipse/emf/compare/merge/ReferenceChangeMerger.java1506
1 files changed, 753 insertions, 753 deletions
diff --git a/plugins/org.eclipse.emf.compare/src/org/eclipse/emf/compare/merge/ReferenceChangeMerger.java b/plugins/org.eclipse.emf.compare/src/org/eclipse/emf/compare/merge/ReferenceChangeMerger.java
index f77eef08e..ce9d162b4 100644
--- a/plugins/org.eclipse.emf.compare/src/org/eclipse/emf/compare/merge/ReferenceChangeMerger.java
+++ b/plugins/org.eclipse.emf.compare/src/org/eclipse/emf/compare/merge/ReferenceChangeMerger.java
@@ -1,753 +1,753 @@
-/*******************************************************************************
- * Copyright (c) 2012, 2013 Obeo.
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Eclipse Public License v1.0
- * which accompanies this distribution, and is available at
- * http://www.eclipse.org/legal/epl-v10.html
- *
- * Contributors:
- * Obeo - initial API and implementation
- *******************************************************************************/
-package org.eclipse.emf.compare.merge;
-
-import static org.eclipse.emf.compare.utils.ReferenceUtil.safeEIsSet;
-
-import com.google.common.base.Predicates;
-import com.google.common.collect.Iterables;
-
-import java.util.Iterator;
-import java.util.List;
-
-import org.eclipse.emf.common.util.EList;
-import org.eclipse.emf.common.util.Monitor;
-import org.eclipse.emf.compare.Comparison;
-import org.eclipse.emf.compare.Diff;
-import org.eclipse.emf.compare.DifferenceSource;
-import org.eclipse.emf.compare.DifferenceState;
-import org.eclipse.emf.compare.Match;
-import org.eclipse.emf.compare.ReferenceChange;
-import org.eclipse.emf.compare.internal.utils.DiffUtil;
-import org.eclipse.emf.compare.utils.IEqualityHelper;
-import org.eclipse.emf.ecore.EObject;
-import org.eclipse.emf.ecore.EReference;
-import org.eclipse.emf.ecore.resource.Resource;
-import org.eclipse.emf.ecore.util.EcoreUtil;
-import org.eclipse.emf.ecore.xmi.XMIResource;
-
-/**
- * This specific implementation of {@link AbstractMerger} will be used to merge reference changes.
- *
- * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
- */
-public class ReferenceChangeMerger extends AbstractMerger {
- /**
- * {@inheritDoc}
- *
- * @see org.eclipse.emf.compare.merge.IMerger#isMergerFor(org.eclipse.emf.compare.Diff)
- */
- public boolean isMergerFor(Diff target) {
- return target instanceof ReferenceChange;
- }
-
- /**
- * {@inheritDoc}
- *
- * @see org.eclipse.emf.compare.merge.IMerger#copyLeftToRight(org.eclipse.emf.compare.Diff,
- * org.eclipse.emf.common.util.Monitor)
- */
- public void copyLeftToRight(Diff target, Monitor monitor) {
- // Don't merge an already merged (or discarded) diff
- if (target.getState() != DifferenceState.UNRESOLVED) {
- return;
- }
- final ReferenceChange diff = (ReferenceChange)target;
-
- // Change the diff's state before we actually merge it : this allows us to avoid requirement cycles.
- diff.setState(DifferenceState.MERGED);
-
- if (diff.getSource() == DifferenceSource.LEFT) {
- // merge all "requires" diffs
- mergeRequires(diff, false, monitor);
- handleImplies(diff, false, monitor);
- } else {
- // merge all "required by" diffs
- mergeRequiredBy(diff, false, monitor);
- handleImpliedBy(diff, false, monitor);
- }
-
- boolean hasToBeMerged = true;
- if (diff.getEquivalence() != null) {
- hasToBeMerged = handleEquivalences(diff, false, monitor);
- }
-
- if (hasToBeMerged) {
- if (diff.getSource() == DifferenceSource.LEFT) {
- accept(diff, false);
- } else {
- reject(diff, false);
- }
- }
- }
-
- /**
- * {@inheritDoc}
- *
- * @see org.eclipse.emf.compare.merge.IMerger#copyRightToLeft(org.eclipse.emf.compare.Diff,
- * org.eclipse.emf.common.util.Monitor)
- */
- public void copyRightToLeft(Diff target, Monitor monitor) {
- // Don't merge an already merged (or discarded) diff
- if (target.getState() != DifferenceState.UNRESOLVED) {
- return;
- }
- final ReferenceChange diff = (ReferenceChange)target;
-
- // Change the diff's state before we actually merge it : this allows us to avoid requirement cycles.
- diff.setState(DifferenceState.MERGED);
-
- if (diff.getSource() == DifferenceSource.LEFT) {
- // merge all "required by" diffs
- mergeRequiredBy(diff, true, monitor);
- handleImpliedBy(diff, true, monitor);
- } else {
- // merge all "requires" diffs
- mergeRequires(diff, true, monitor);
- handleImplies(diff, true, monitor);
- }
-
- boolean hasToBeMerged = true;
- if (diff.getEquivalence() != null) {
- hasToBeMerged = handleEquivalences(diff, true, monitor);
- }
-
- if (hasToBeMerged) {
- if (diff.getSource() == DifferenceSource.LEFT) {
- reject(diff, true);
- } else {
- accept(diff, true);
- }
- }
- }
-
- /**
- * Merge the given difference rejecting it.
- *
- * @param diff
- * The difference to merge.
- * @param rightToLeft
- * The direction of the merge.
- */
- private void reject(final ReferenceChange diff, boolean rightToLeft) {
- DifferenceSource source = diff.getSource();
- switch (diff.getKind()) {
- case ADD:
- // We have a ADD on left, thus nothing in right. We need to revert the addition
- removeFromTarget(diff, rightToLeft);
- break;
- case DELETE:
- // DELETE in the left, thus an element in right. We need to re-create that element
- addInTarget(diff, rightToLeft);
- break;
- case MOVE:
- moveElement(diff, rightToLeft);
- break;
- case CHANGE:
- EObject container = null;
- if (source == DifferenceSource.LEFT) {
- container = diff.getMatch().getLeft();
-
- } else {
- container = diff.getMatch().getRight();
- }
- // Is it an unset?
- if (container != null) {
- final EObject leftValue = (EObject)container.eGet(diff.getReference(), false);
- if (leftValue == null) {
- // Value has been unset in the right, and we are merging towards right.
- // We need to re-add this element
- addInTarget(diff, rightToLeft);
- } else {
- // We'll actually need to "reset" this reference to its original value
- resetInTarget(diff, rightToLeft);
- }
- } else {
- // we have no left, and the source is on the left. Can only be an unset
- addInTarget(diff, rightToLeft);
- }
- break;
- default:
- break;
- }
- }
-
- /**
- * Merge the given difference accepting it.
- *
- * @param diff
- * The difference to merge.
- * @param rightToLeft
- * The direction of the merge.
- */
- private void accept(final ReferenceChange diff, boolean rightToLeft) {
- DifferenceSource source = diff.getSource();
- switch (diff.getKind()) {
- case ADD:
- // Create the same element in right
- addInTarget(diff, rightToLeft);
- break;
- case DELETE:
- // Delete that same element from right
- removeFromTarget(diff, rightToLeft);
- break;
- case MOVE:
- moveElement(diff, rightToLeft);
- break;
- case CHANGE:
- EObject container = null;
- if (source == DifferenceSource.LEFT) {
- container = diff.getMatch().getLeft();
- } else {
- container = diff.getMatch().getRight();
- }
- // Is it an unset?
- if (container != null) {
- final EObject leftValue = (EObject)container.eGet(diff.getReference(), false);
- if (leftValue == null) {
- removeFromTarget(diff, rightToLeft);
- } else {
- addInTarget(diff, rightToLeft);
- }
- } else {
- // we have no left, and the source is on the left. Can only be an unset
- removeFromTarget(diff, rightToLeft);
- }
- break;
- default:
- break;
- }
- }
-
- /**
- * Mark as MERGED all the implied differences recursively from the given one.
- *
- * @param diff
- * The difference from which the implications have to be marked.
- * @param rightToLeft
- * The direction of the merge.
- * @param monitor
- * Monitor.
- */
- private void handleImplies(Diff diff, boolean rightToLeft, Monitor monitor) {
- for (Diff implied : diff.getImplies()) {
- implied.setState(DifferenceState.MERGED);
- handleImplies(implied, rightToLeft, monitor);
- }
- }
-
- /**
- * Mark as MERGED all the implying differences recursively from the given one.
- *
- * @param diff
- * The difference from which the implications have to be marked.
- * @param rightToLeft
- * The direction of the merge.
- * @param monitor
- * Monitor.
- */
- private void handleImpliedBy(Diff diff, boolean rightToLeft, Monitor monitor) {
- for (Diff impliedBy : diff.getImpliedBy()) {
- impliedBy.setState(DifferenceState.MERGED);
- handleImpliedBy(impliedBy, rightToLeft, monitor);
- }
- }
-
- /**
- * This will be called when trying to copy a "MOVE" diff.
- *
- * @param diff
- * The diff we are currently merging.
- * @param rightToLeft
- * Whether we should move the value in the left or right side.
- */
- protected void moveElement(ReferenceChange diff, boolean rightToLeft) {
- final Comparison comparison = diff.getMatch().getComparison();
- final Match valueMatch = comparison.getMatch(diff.getValue());
- final EReference reference = diff.getReference();
-
- final EObject expectedContainer;
- if (reference.isContainment()) {
- /*
- * We cannot "trust" the holding match (getMatch) in this case. However, "valueMatch" cannot be
- * null : we cannot have detected a move if the moved element is not matched on both sides. Use
- * that information to retrieve the proper "target" container.
- */
- final Match targetContainerMatch;
- // If it exists, use the source side's container as reference
- if (rightToLeft && valueMatch.getRight() != null) {
- targetContainerMatch = comparison.getMatch(valueMatch.getRight().eContainer());
- } else if (!rightToLeft && valueMatch.getLeft() != null) {
- targetContainerMatch = comparison.getMatch(valueMatch.getLeft().eContainer());
- } else {
- // Otherwise, the value we're moving on one side has been removed from its source side.
- targetContainerMatch = comparison.getMatch(valueMatch.getOrigin().eContainer());
- }
- if (rightToLeft) {
- expectedContainer = targetContainerMatch.getLeft();
- } else {
- expectedContainer = targetContainerMatch.getRight();
- }
- } else if (rightToLeft) {
- expectedContainer = diff.getMatch().getLeft();
- } else {
- expectedContainer = diff.getMatch().getRight();
- }
- if (expectedContainer == null) {
- // FIXME throw exception? log? re-try to merge our requirements?
- // one of the "required" diffs should have created our container.
- return;
- }
-
- final EObject expectedValue;
- if (valueMatch == null) {
- // The value being moved is out of the scope
- /*
- * Note : there should not be a way to end up with a "move" for an out of scope value : a move can
- * only be detected if the object is matched on both sides, otherwise all we can see is "add" and
- * "delete"... Is this "fallback" code even reachable? If so, how?
- */
- // We need to look it up
- if (reference.isMany()) {
- @SuppressWarnings("unchecked")
- final List<EObject> targetList = (List<EObject>)expectedContainer.eGet(reference);
- expectedValue = findMatchIn(comparison, targetList, diff.getValue());
- } else {
- expectedValue = (EObject)expectedContainer.eGet(reference);
- }
- } else {
- if (rightToLeft) {
- expectedValue = valueMatch.getLeft();
- } else {
- expectedValue = valueMatch.getRight();
- }
- }
- // We now know the target container, target reference and target value.
- doMove(diff, comparison, expectedContainer, expectedValue, rightToLeft);
- }
-
- /**
- * This will do the actual work of moving the element into its reference. All sanity checks were made in
- * {@link #moveElement(boolean)} and no more verification will be made here.
- *
- * @param diff
- * The diff we are currently merging.
- * @param comparison
- * Comparison holding this Diff.
- * @param expectedContainer
- * The container in which we are reorganizing a reference.
- * @param expectedValue
- * The value that is to be moved within its reference.
- * @param rightToLeft
- * Whether we should move the value in the left or right side.
- */
- @SuppressWarnings("unchecked")
- protected void doMove(ReferenceChange diff, Comparison comparison, EObject expectedContainer,
- EObject expectedValue, boolean rightToLeft) {
- final EReference reference = diff.getReference();
- if (reference.isMany()) {
- // Element to move cannot be part of the LCS... or there would not be a MOVE diff
- int insertionIndex = findInsertionIndex(comparison, diff, rightToLeft);
-
- /*
- * However, it could still have been located "before" its new index, in which case we need to take
- * it into account.
- */
- final List<EObject> targetList = (List<EObject>)expectedContainer.eGet(reference);
- final int currentIndex = targetList.indexOf(expectedValue);
- if (insertionIndex > currentIndex && currentIndex >= 0) {
- insertionIndex--;
- }
-
- if (currentIndex == -1) {
- // happens for container changes for example.
- if (!reference.isContainment()) {
- targetList.remove(expectedValue);
- }
- if (insertionIndex < 0 && insertionIndex > targetList.size()) {
- targetList.add(expectedValue);
- } else {
- targetList.add(insertionIndex, expectedValue);
- }
- } else if (targetList instanceof EList<?>) {
- if (insertionIndex < 0 && insertionIndex > targetList.size()) {
- ((EList<EObject>)targetList).move(targetList.size() - 1, expectedValue);
- } else {
- ((EList<EObject>)targetList).move(insertionIndex, expectedValue);
- }
- } else {
- targetList.remove(expectedValue);
- if (insertionIndex < 0 && insertionIndex > targetList.size()) {
- targetList.add(expectedValue);
- } else {
- targetList.add(insertionIndex, expectedValue);
- }
- }
- } else {
- expectedContainer.eSet(reference, expectedValue);
- }
- }
-
- /**
- * This will be called when we need to create an element in the target side.
- * <p>
- * All necessary sanity checks have been made to ensure that the current operation is one that should
- * create an object in its side or add an objet to a reference. In other words, either :
- * <ul>
- * <li>We are copying from right to left and
- * <ul>
- * <li>we are copying an addition to the right side (we need to create the same object in the left), or</li>
- * <li>we are copying a deletion from the left side (we need to revert the deletion).</li>
- * </ul>
- * </li>
- * <li>We are copying from left to right and
- * <ul>
- * <li>we are copying a deletion from the right side (we need to revert the deletion), or</li>
- * <li>we are copying an addition to the left side (we need to create the same object in the right).</li>
- * </ul>
- * </li>
- * </ul>
- * </p>
- *
- * @param diff
- * The diff we are currently merging.
- * @param rightToLeft
- * Tells us whether we are to add an object on the left or right side.
- */
- @SuppressWarnings("unchecked")
- protected void addInTarget(ReferenceChange diff, boolean rightToLeft) {
- final Match match = diff.getMatch();
- final EObject expectedContainer;
- if (rightToLeft) {
- expectedContainer = match.getLeft();
- } else {
- expectedContainer = match.getRight();
- }
-
- if (expectedContainer == null) {
- // FIXME throw exception? log? re-try to merge our requirements?
- // one of the "required" diffs should have created our container.
- return;
- }
-
- final Comparison comparison = match.getComparison();
- final EReference reference = diff.getReference();
- final EObject expectedValue;
- final Match valueMatch = comparison.getMatch(diff.getValue());
- if (valueMatch == null) {
- // This is an out of scope value.
- if (diff.getValue().eIsProxy()) {
- // Copy the proxy
- expectedValue = EcoreUtil.copy(diff.getValue());
- } else {
- // Use the same value.
- expectedValue = diff.getValue();
- }
- } else if (rightToLeft) {
- if (reference.isContainment()) {
- expectedValue = createCopy(diff.getValue());
- valueMatch.setLeft(expectedValue);
- } else {
- expectedValue = valueMatch.getLeft();
- }
- } else {
- if (reference.isContainment()) {
- expectedValue = createCopy(diff.getValue());
- valueMatch.setRight(expectedValue);
- } else {
- expectedValue = valueMatch.getRight();
- }
- }
-
- // We have the container, reference and value. We need to know the insertion index.
- if (reference.isMany()) {
- final int insertionIndex = findInsertionIndex(comparison, diff, rightToLeft);
-
- final List<EObject> targetList = (List<EObject>)expectedContainer.eGet(reference);
- addAt(targetList, expectedValue, insertionIndex);
- } else {
- expectedContainer.eSet(reference, expectedValue);
- }
-
- if (reference.isContainment()) {
- // Copy XMI ID when applicable.
- final Resource initialResource = diff.getValue().eResource();
- final Resource targetResource = expectedValue.eResource();
- if (initialResource instanceof XMIResource && targetResource instanceof XMIResource) {
- ((XMIResource)targetResource).setID(expectedValue, ((XMIResource)initialResource).getID(diff
- .getValue()));
- }
- }
- }
-
- /**
- * This will be called when we need to remove an element from the target side.
- * <p>
- * All necessary sanity checks have been made to ensure that the current operation is one that should
- * delete an object. In other words, we are :
- * <ul>
- * <li>Copying from right to left and either
- * <ul>
- * <li>we are copying a deletion from the right side (we need to remove the same object in the left) or,</li>
- * <li>we are copying an addition to the left side (we need to revert the addition).</li>
- * </ul>
- * </li>
- * <li>Copying from left to right and either
- * <ul>
- * <li>we are copying an addition to the right side (we need to revert the addition), or.</li>
- * <li>we are copying a deletion from the left side (we need to remove the same object in the right).</li>
- * </ul>
- * </li>
- * </ul>
- * </p>
- *
- * @param diff
- * The diff we are currently merging.
- * @param rightToLeft
- * Tells us whether we are to add an object on the left or right side.
- */
- @SuppressWarnings("unchecked")
- protected void removeFromTarget(ReferenceChange diff, boolean rightToLeft) {
- final Match match = diff.getMatch();
- final EReference reference = diff.getReference();
- final EObject currentContainer;
- if (rightToLeft) {
- currentContainer = match.getLeft();
- } else {
- currentContainer = match.getRight();
- }
- final Comparison comparison = match.getComparison();
- final Match valueMatch = comparison.getMatch(diff.getValue());
-
- if (currentContainer == null) {
- // FIXME throw exception? log? re-try to merge our requirements?
- // one of the "required" diffs should have created our container.
- return;
- }
-
- final EObject expectedValue;
- if (valueMatch == null) {
- // value is out of the scope... we need to look it up
- if (reference.isMany()) {
- final List<EObject> targetList = (List<EObject>)currentContainer.eGet(reference);
- expectedValue = findMatchIn(comparison, targetList, diff.getValue());
- } else {
- // the value will not be needed anyway
- expectedValue = null;
- }
- } else if (rightToLeft) {
- expectedValue = valueMatch.getLeft();
- } else {
- expectedValue = valueMatch.getRight();
- }
-
- // We have the container, reference and value to remove. Expected value can be null when the
- // deletion was made on both side (i.e. a pseudo delete)
- if (reference.isContainment() && expectedValue != null) {
- EcoreUtil.remove(expectedValue);
- if (rightToLeft && valueMatch != null) {
- valueMatch.setLeft(null);
- } else if (valueMatch != null) {
- valueMatch.setRight(null);
- }
- // TODO remove dangling? remove empty Match?
- } else if (reference.isMany()) {
- /*
- * TODO if the same value appears twice, should we try and find the one that has actually been
- * deleted? Can it happen? For now, remove the first occurence we find.
- */
- final List<EObject> targetList = (List<EObject>)currentContainer.eGet(reference);
- targetList.remove(expectedValue);
- } else {
- currentContainer.eUnset(reference);
- }
- }
-
- /**
- * This will be called by the merge operations in order to reset a reference to its original value, be
- * that the left or right side.
- * <p>
- * Should never be called on multi-valued references.
- * </p>
- *
- * @param diff
- * The diff we are currently merging.
- * @param rightToLeft
- * Tells us the direction of this merge operation.
- */
- protected void resetInTarget(ReferenceChange diff, boolean rightToLeft) {
- final Match match = diff.getMatch();
- final EReference reference = diff.getReference();
- final EObject targetContainer;
- if (rightToLeft) {
- targetContainer = match.getLeft();
- } else {
- targetContainer = match.getRight();
- }
-
- final EObject originContainer;
- if (match.getComparison().isThreeWay()) {
- originContainer = match.getOrigin();
- } else if (rightToLeft) {
- originContainer = match.getRight();
- } else {
- originContainer = match.getLeft();
- }
-
- if (originContainer == null || !safeEIsSet(targetContainer, reference)
- || !safeEIsSet(originContainer, reference)) {
- targetContainer.eUnset(reference);
- } else {
- final EObject originalValue = (EObject)originContainer.eGet(reference);
- final Match valueMatch = match.getComparison().getMatch(originalValue);
- final EObject expectedValue;
- if (valueMatch == null) {
- // Value is out of the scope, use it as-is
- expectedValue = originalValue;
- } else if (rightToLeft) {
- expectedValue = valueMatch.getLeft();
- } else {
- expectedValue = valueMatch.getRight();
- }
- targetContainer.eSet(reference, expectedValue);
- }
- }
-
- /**
- * Handles the equivalences of this difference.
- * <p>
- * Note that in certain cases, we'll merge our opposite instead of merging this diff. Specifically, we'll
- * do that for one-to-many eOpposites : we'll merge the 'many' side instead of the 'unique' one. This
- * allows us not to worry about the order of the references on that 'many' side.
- * </p>
- * <p>
- * This is called before the merge of <code>this</code>. In short, if this returns <code>false</code>, we
- * won't carry on merging <code>this</code> after returning.
- * </p>
- *
- * @param diff
- * The diff we are currently merging.
- * @param rightToLeft
- * Direction of the merge.
- * @param monitor
- * The monitor to use in order to report progress information.
- * @return <code>true</code> if the current difference should still be merged after handling its
- * equivalences, <code>false</code> if it should be considered "already merged".
- */
- protected boolean handleEquivalences(ReferenceChange diff, boolean rightToLeft, Monitor monitor) {
- final EReference reference = diff.getReference();
- boolean continueMerge = true;
- for (Diff equivalent : diff.getEquivalence().getDifferences()) {
- // For 1..*, merge diff on many-valued to preserve ordering
- if (equivalent instanceof ReferenceChange
- && reference.getEOpposite() == ((ReferenceChange)equivalent).getReference()
- && equivalent.getState() == DifferenceState.UNRESOLVED) {
- // This equivalence is on our eOpposite. Should we merge it instead of 'this'?
- final boolean mergeEquivalence = !reference.isMany()
- && ((ReferenceChange)equivalent).getReference().isMany();
- if (mergeEquivalence) {
- mergeDiff(equivalent, rightToLeft, monitor);
- continueMerge = false;
- }
- }
-
- /*
- * If one of the equivalent differences is implied or implying (depending on the merge direction)
- * a merged diff, then we have a dependency loop : the "current" difference has already been
- * merged because of this implication. This will allow us to break out of that loop.
- */
- if (rightToLeft) {
- if (diff.getSource() == DifferenceSource.LEFT) {
- continueMerge = continueMerge
- && !containsAny(diff.getRequiredBy(), equivalent.getImplies());
- } else {
- continueMerge = continueMerge
- && !containsAny(diff.getRequires(), equivalent.getImpliedBy());
- }
- } else {
- if (diff.getSource() == DifferenceSource.LEFT) {
- continueMerge = continueMerge
- && !containsAny(diff.getRequires(), equivalent.getImpliedBy());
- } else {
- continueMerge = continueMerge
- && !containsAny(diff.getRequiredBy(), equivalent.getImplies());
- }
- }
-
- equivalent.setState(DifferenceState.MERGED);
- }
- return continueMerge;
- }
-
- /**
- * Utility method to check that the first sequence contains one of the elements of the second sequence at
- * least.
- *
- * @param sequence1
- * The first sequence.
- * @param sequence2
- * The second sequence.
- * @return True if the given first sequence contains one of the elements of the second sequence at least.
- * false otherwise.
- */
- private boolean containsAny(List<? extends EObject> sequence1, List<? extends EObject> sequence2) {
- return Iterables.any(sequence2, Predicates.in(sequence1));
- }
-
- /**
- * Seeks a match of the given {@code element} in the given list, using the equality helper to find it.
- * This is only used when moving or deleting proxies for now.
- *
- * @param comparison
- * The comparison which Diff we are currently merging.
- * @param list
- * The list from which we seek a value.
- * @param element
- * The value for which we need a match in {@code list}.
- * @return The match of {@code element} in {@code list}, {@code null} if none.
- */
- protected EObject findMatchIn(Comparison comparison, List<EObject> list, EObject element) {
- final IEqualityHelper helper = comparison.getEqualityHelper();
- final Iterator<EObject> it = list.iterator();
- while (it.hasNext()) {
- final EObject next = it.next();
- if (helper.matchingValues(next, element)) {
- return next;
- }
- }
- return null;
- }
-
- /**
- * This will be used by the distinct merge actions in order to find the index at which a value should be
- * inserted in its target list. See {@link DiffUtil#findInsertionIndex(Comparison, Diff, boolean)} for
- * more on this.
- * <p>
- * Sub-classes can override this if the insertion order is irrelevant. A return value of {@code -1} will
- * be considered as "no index" and the value will be inserted at the end of its target list.
- * </p>
- *
- * @param comparison
- * This will be used in order to retrieve the Match for EObjects when comparing them.
- * @param diff
- * The diff which merging will trigger the need for an insertion index in its target list.
- * @param rightToLeft
- * {@code true} if the merging will be done into the left list, so that we should consider the
- * right model as the source and the left as the target.
- * @return The index at which this {@code diff}'s value should be inserted into the 'target' list, as
- * inferred from {@code rightToLeft}. {@code -1} if the value should be inserted at the end of its
- * target list.
- * @see DiffUtil#findInsertionIndex(Comparison, Diff, boolean)
- */
- protected int findInsertionIndex(Comparison comparison, Diff diff, boolean rightToLeft) {
- return DiffUtil.findInsertionIndex(comparison, diff, rightToLeft);
- }
-}
+/*******************************************************************************
+ * Copyright (c) 2012, 2013 Obeo.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ * Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.emf.compare.merge;
+
+import static org.eclipse.emf.compare.utils.ReferenceUtil.safeEIsSet;
+
+import com.google.common.base.Predicates;
+import com.google.common.collect.Iterables;
+
+import java.util.Iterator;
+import java.util.List;
+
+import org.eclipse.emf.common.util.EList;
+import org.eclipse.emf.common.util.Monitor;
+import org.eclipse.emf.compare.Comparison;
+import org.eclipse.emf.compare.Diff;
+import org.eclipse.emf.compare.DifferenceSource;
+import org.eclipse.emf.compare.DifferenceState;
+import org.eclipse.emf.compare.Match;
+import org.eclipse.emf.compare.ReferenceChange;
+import org.eclipse.emf.compare.internal.utils.DiffUtil;
+import org.eclipse.emf.compare.utils.IEqualityHelper;
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.emf.ecore.EReference;
+import org.eclipse.emf.ecore.resource.Resource;
+import org.eclipse.emf.ecore.util.EcoreUtil;
+import org.eclipse.emf.ecore.xmi.XMIResource;
+
+/**
+ * This specific implementation of {@link AbstractMerger} will be used to merge reference changes.
+ *
+ * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
+ */
+public class ReferenceChangeMerger extends AbstractMerger {
+ /**
+ * {@inheritDoc}
+ *
+ * @see org.eclipse.emf.compare.merge.IMerger#isMergerFor(org.eclipse.emf.compare.Diff)
+ */
+ public boolean isMergerFor(Diff target) {
+ return target instanceof ReferenceChange;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @see org.eclipse.emf.compare.merge.IMerger#copyLeftToRight(org.eclipse.emf.compare.Diff,
+ * org.eclipse.emf.common.util.Monitor)
+ */
+ public void copyLeftToRight(Diff target, Monitor monitor) {
+ // Don't merge an already merged (or discarded) diff
+ if (target.getState() != DifferenceState.UNRESOLVED) {
+ return;
+ }
+ final ReferenceChange diff = (ReferenceChange)target;
+
+ // Change the diff's state before we actually merge it : this allows us to avoid requirement cycles.
+ diff.setState(DifferenceState.MERGED);
+
+ if (diff.getSource() == DifferenceSource.LEFT) {
+ // merge all "requires" diffs
+ mergeRequires(diff, false, monitor);
+ handleImplies(diff, false, monitor);
+ } else {
+ // merge all "required by" diffs
+ mergeRequiredBy(diff, false, monitor);
+ handleImpliedBy(diff, false, monitor);
+ }
+
+ boolean hasToBeMerged = true;
+ if (diff.getEquivalence() != null) {
+ hasToBeMerged = handleEquivalences(diff, false, monitor);
+ }
+
+ if (hasToBeMerged) {
+ if (diff.getSource() == DifferenceSource.LEFT) {
+ accept(diff, false);
+ } else {
+ reject(diff, false);
+ }
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @see org.eclipse.emf.compare.merge.IMerger#copyRightToLeft(org.eclipse.emf.compare.Diff,
+ * org.eclipse.emf.common.util.Monitor)
+ */
+ public void copyRightToLeft(Diff target, Monitor monitor) {
+ // Don't merge an already merged (or discarded) diff
+ if (target.getState() != DifferenceState.UNRESOLVED) {
+ return;
+ }
+ final ReferenceChange diff = (ReferenceChange)target;
+
+ // Change the diff's state before we actually merge it : this allows us to avoid requirement cycles.
+ diff.setState(DifferenceState.MERGED);
+
+ if (diff.getSource() == DifferenceSource.LEFT) {
+ // merge all "required by" diffs
+ mergeRequiredBy(diff, true, monitor);
+ handleImpliedBy(diff, true, monitor);
+ } else {
+ // merge all "requires" diffs
+ mergeRequires(diff, true, monitor);
+ handleImplies(diff, true, monitor);
+ }
+
+ boolean hasToBeMerged = true;
+ if (diff.getEquivalence() != null) {
+ hasToBeMerged = handleEquivalences(diff, true, monitor);
+ }
+
+ if (hasToBeMerged) {
+ if (diff.getSource() == DifferenceSource.LEFT) {
+ reject(diff, true);
+ } else {
+ accept(diff, true);
+ }
+ }
+ }
+
+ /**
+ * Merge the given difference rejecting it.
+ *
+ * @param diff
+ * The difference to merge.
+ * @param rightToLeft
+ * The direction of the merge.
+ */
+ private void reject(final ReferenceChange diff, boolean rightToLeft) {
+ DifferenceSource source = diff.getSource();
+ switch (diff.getKind()) {
+ case ADD:
+ // We have a ADD on left, thus nothing in right. We need to revert the addition
+ removeFromTarget(diff, rightToLeft);
+ break;
+ case DELETE:
+ // DELETE in the left, thus an element in right. We need to re-create that element
+ addInTarget(diff, rightToLeft);
+ break;
+ case MOVE:
+ moveElement(diff, rightToLeft);
+ break;
+ case CHANGE:
+ EObject container = null;
+ if (source == DifferenceSource.LEFT) {
+ container = diff.getMatch().getLeft();
+
+ } else {
+ container = diff.getMatch().getRight();
+ }
+ // Is it an unset?
+ if (container != null) {
+ final EObject leftValue = (EObject)container.eGet(diff.getReference(), false);
+ if (leftValue == null) {
+ // Value has been unset in the right, and we are merging towards right.
+ // We need to re-add this element
+ addInTarget(diff, rightToLeft);
+ } else {
+ // We'll actually need to "reset" this reference to its original value
+ resetInTarget(diff, rightToLeft);
+ }
+ } else {
+ // we have no left, and the source is on the left. Can only be an unset
+ addInTarget(diff, rightToLeft);
+ }
+ break;
+ default:
+ break;
+ }
+ }
+
+ /**
+ * Merge the given difference accepting it.
+ *
+ * @param diff
+ * The difference to merge.
+ * @param rightToLeft
+ * The direction of the merge.
+ */
+ private void accept(final ReferenceChange diff, boolean rightToLeft) {
+ DifferenceSource source = diff.getSource();
+ switch (diff.getKind()) {
+ case ADD:
+ // Create the same element in right
+ addInTarget(diff, rightToLeft);
+ break;
+ case DELETE:
+ // Delete that same element from right
+ removeFromTarget(diff, rightToLeft);
+ break;
+ case MOVE:
+ moveElement(diff, rightToLeft);
+ break;
+ case CHANGE:
+ EObject container = null;
+ if (source == DifferenceSource.LEFT) {
+ container = diff.getMatch().getLeft();
+ } else {
+ container = diff.getMatch().getRight();
+ }
+ // Is it an unset?
+ if (container != null) {
+ final EObject leftValue = (EObject)container.eGet(diff.getReference(), false);
+ if (leftValue == null) {
+ removeFromTarget(diff, rightToLeft);
+ } else {
+ addInTarget(diff, rightToLeft);
+ }
+ } else {
+ // we have no left, and the source is on the left. Can only be an unset
+ removeFromTarget(diff, rightToLeft);
+ }
+ break;
+ default:
+ break;
+ }
+ }
+
+ /**
+ * Mark as MERGED all the implied differences recursively from the given one.
+ *
+ * @param diff
+ * The difference from which the implications have to be marked.
+ * @param rightToLeft
+ * The direction of the merge.
+ * @param monitor
+ * Monitor.
+ */
+ private void handleImplies(Diff diff, boolean rightToLeft, Monitor monitor) {
+ for (Diff implied : diff.getImplies()) {
+ implied.setState(DifferenceState.MERGED);
+ handleImplies(implied, rightToLeft, monitor);
+ }
+ }
+
+ /**
+ * Mark as MERGED all the implying differences recursively from the given one.
+ *
+ * @param diff
+ * The difference from which the implications have to be marked.
+ * @param rightToLeft
+ * The direction of the merge.
+ * @param monitor
+ * Monitor.
+ */
+ private void handleImpliedBy(Diff diff, boolean rightToLeft, Monitor monitor) {
+ for (Diff impliedBy : diff.getImpliedBy()) {
+ impliedBy.setState(DifferenceState.MERGED);
+ handleImpliedBy(impliedBy, rightToLeft, monitor);
+ }
+ }
+
+ /**
+ * This will be called when trying to copy a "MOVE" diff.
+ *
+ * @param diff
+ * The diff we are currently merging.
+ * @param rightToLeft
+ * Whether we should move the value in the left or right side.
+ */
+ protected void moveElement(ReferenceChange diff, boolean rightToLeft) {
+ final Comparison comparison = diff.getMatch().getComparison();
+ final Match valueMatch = comparison.getMatch(diff.getValue());
+ final EReference reference = diff.getReference();
+
+ final EObject expectedContainer;
+ if (reference.isContainment()) {
+ /*
+ * We cannot "trust" the holding match (getMatch) in this case. However, "valueMatch" cannot be
+ * null : we cannot have detected a move if the moved element is not matched on both sides. Use
+ * that information to retrieve the proper "target" container.
+ */
+ final Match targetContainerMatch;
+ // If it exists, use the source side's container as reference
+ if (rightToLeft && valueMatch.getRight() != null) {
+ targetContainerMatch = comparison.getMatch(valueMatch.getRight().eContainer());
+ } else if (!rightToLeft && valueMatch.getLeft() != null) {
+ targetContainerMatch = comparison.getMatch(valueMatch.getLeft().eContainer());
+ } else {
+ // Otherwise, the value we're moving on one side has been removed from its source side.
+ targetContainerMatch = comparison.getMatch(valueMatch.getOrigin().eContainer());
+ }
+ if (rightToLeft) {
+ expectedContainer = targetContainerMatch.getLeft();
+ } else {
+ expectedContainer = targetContainerMatch.getRight();
+ }
+ } else if (rightToLeft) {
+ expectedContainer = diff.getMatch().getLeft();
+ } else {
+ expectedContainer = diff.getMatch().getRight();
+ }
+ if (expectedContainer == null) {
+ // FIXME throw exception? log? re-try to merge our requirements?
+ // one of the "required" diffs should have created our container.
+ return;
+ }
+
+ final EObject expectedValue;
+ if (valueMatch == null) {
+ // The value being moved is out of the scope
+ /*
+ * Note : there should not be a way to end up with a "move" for an out of scope value : a move can
+ * only be detected if the object is matched on both sides, otherwise all we can see is "add" and
+ * "delete"... Is this "fallback" code even reachable? If so, how?
+ */
+ // We need to look it up
+ if (reference.isMany()) {
+ @SuppressWarnings("unchecked")
+ final List<EObject> targetList = (List<EObject>)expectedContainer.eGet(reference);
+ expectedValue = findMatchIn(comparison, targetList, diff.getValue());
+ } else {
+ expectedValue = (EObject)expectedContainer.eGet(reference);
+ }
+ } else {
+ if (rightToLeft) {
+ expectedValue = valueMatch.getLeft();
+ } else {
+ expectedValue = valueMatch.getRight();
+ }
+ }
+ // We now know the target container, target reference and target value.
+ doMove(diff, comparison, expectedContainer, expectedValue, rightToLeft);
+ }
+
+ /**
+ * This will do the actual work of moving the element into its reference. All sanity checks were made in
+ * {@link #moveElement(boolean)} and no more verification will be made here.
+ *
+ * @param diff
+ * The diff we are currently merging.
+ * @param comparison
+ * Comparison holding this Diff.
+ * @param expectedContainer
+ * The container in which we are reorganizing a reference.
+ * @param expectedValue
+ * The value that is to be moved within its reference.
+ * @param rightToLeft
+ * Whether we should move the value in the left or right side.
+ */
+ @SuppressWarnings("unchecked")
+ protected void doMove(ReferenceChange diff, Comparison comparison, EObject expectedContainer,
+ EObject expectedValue, boolean rightToLeft) {
+ final EReference reference = diff.getReference();
+ if (reference.isMany()) {
+ // Element to move cannot be part of the LCS... or there would not be a MOVE diff
+ int insertionIndex = findInsertionIndex(comparison, diff, rightToLeft);
+
+ /*
+ * However, it could still have been located "before" its new index, in which case we need to take
+ * it into account.
+ */
+ final List<EObject> targetList = (List<EObject>)expectedContainer.eGet(reference);
+ final int currentIndex = targetList.indexOf(expectedValue);
+ if (insertionIndex > currentIndex && currentIndex >= 0) {
+ insertionIndex--;
+ }
+
+ if (currentIndex == -1) {
+ // happens for container changes for example.
+ if (!reference.isContainment()) {
+ targetList.remove(expectedValue);
+ }
+ if (insertionIndex < 0 && insertionIndex > targetList.size()) {
+ targetList.add(expectedValue);
+ } else {
+ targetList.add(insertionIndex, expectedValue);
+ }
+ } else if (targetList instanceof EList<?>) {
+ if (insertionIndex < 0 && insertionIndex > targetList.size()) {
+ ((EList<EObject>)targetList).move(targetList.size() - 1, expectedValue);
+ } else {
+ ((EList<EObject>)targetList).move(insertionIndex, expectedValue);
+ }
+ } else {
+ targetList.remove(expectedValue);
+ if (insertionIndex < 0 && insertionIndex > targetList.size()) {
+ targetList.add(expectedValue);
+ } else {
+ targetList.add(insertionIndex, expectedValue);
+ }
+ }
+ } else {
+ expectedContainer.eSet(reference, expectedValue);
+ }
+ }
+
+ /**
+ * This will be called when we need to create an element in the target side.
+ * <p>
+ * All necessary sanity checks have been made to ensure that the current operation is one that should
+ * create an object in its side or add an objet to a reference. In other words, either :
+ * <ul>
+ * <li>We are copying from right to left and
+ * <ul>
+ * <li>we are copying an addition to the right side (we need to create the same object in the left), or</li>
+ * <li>we are copying a deletion from the left side (we need to revert the deletion).</li>
+ * </ul>
+ * </li>
+ * <li>We are copying from left to right and
+ * <ul>
+ * <li>we are copying a deletion from the right side (we need to revert the deletion), or</li>
+ * <li>we are copying an addition to the left side (we need to create the same object in the right).</li>
+ * </ul>
+ * </li>
+ * </ul>
+ * </p>
+ *
+ * @param diff
+ * The diff we are currently merging.
+ * @param rightToLeft
+ * Tells us whether we are to add an object on the left or right side.
+ */
+ @SuppressWarnings("unchecked")
+ protected void addInTarget(ReferenceChange diff, boolean rightToLeft) {
+ final Match match = diff.getMatch();
+ final EObject expectedContainer;
+ if (rightToLeft) {
+ expectedContainer = match.getLeft();
+ } else {
+ expectedContainer = match.getRight();
+ }
+
+ if (expectedContainer == null) {
+ // FIXME throw exception? log? re-try to merge our requirements?
+ // one of the "required" diffs should have created our container.
+ return;
+ }
+
+ final Comparison comparison = match.getComparison();
+ final EReference reference = diff.getReference();
+ final EObject expectedValue;
+ final Match valueMatch = comparison.getMatch(diff.getValue());
+ if (valueMatch == null) {
+ // This is an out of scope value.
+ if (diff.getValue().eIsProxy()) {
+ // Copy the proxy
+ expectedValue = EcoreUtil.copy(diff.getValue());
+ } else {
+ // Use the same value.
+ expectedValue = diff.getValue();
+ }
+ } else if (rightToLeft) {
+ if (reference.isContainment()) {
+ expectedValue = createCopy(diff.getValue());
+ valueMatch.setLeft(expectedValue);
+ } else {
+ expectedValue = valueMatch.getLeft();
+ }
+ } else {
+ if (reference.isContainment()) {
+ expectedValue = createCopy(diff.getValue());
+ valueMatch.setRight(expectedValue);
+ } else {
+ expectedValue = valueMatch.getRight();
+ }
+ }
+
+ // We have the container, reference and value. We need to know the insertion index.
+ if (reference.isMany()) {
+ final int insertionIndex = findInsertionIndex(comparison, diff, rightToLeft);
+
+ final List<EObject> targetList = (List<EObject>)expectedContainer.eGet(reference);
+ addAt(targetList, expectedValue, insertionIndex);
+ } else {
+ expectedContainer.eSet(reference, expectedValue);
+ }
+
+ if (reference.isContainment()) {
+ // Copy XMI ID when applicable.
+ final Resource initialResource = diff.getValue().eResource();
+ final Resource targetResource = expectedValue.eResource();
+ if (initialResource instanceof XMIResource && targetResource instanceof XMIResource) {
+ ((XMIResource)targetResource).setID(expectedValue, ((XMIResource)initialResource).getID(diff
+ .getValue()));
+ }
+ }
+ }
+
+ /**
+ * This will be called when we need to remove an element from the target side.
+ * <p>
+ * All necessary sanity checks have been made to ensure that the current operation is one that should
+ * delete an object. In other words, we are :
+ * <ul>
+ * <li>Copying from right to left and either
+ * <ul>
+ * <li>we are copying a deletion from the right side (we need to remove the same object in the left) or,</li>
+ * <li>we are copying an addition to the left side (we need to revert the addition).</li>
+ * </ul>
+ * </li>
+ * <li>Copying from left to right and either
+ * <ul>
+ * <li>we are copying an addition to the right side (we need to revert the addition), or.</li>
+ * <li>we are copying a deletion from the left side (we need to remove the same object in the right).</li>
+ * </ul>
+ * </li>
+ * </ul>
+ * </p>
+ *
+ * @param diff
+ * The diff we are currently merging.
+ * @param rightToLeft
+ * Tells us whether we are to add an object on the left or right side.
+ */
+ @SuppressWarnings("unchecked")
+ protected void removeFromTarget(ReferenceChange diff, boolean rightToLeft) {
+ final Match match = diff.getMatch();
+ final EReference reference = diff.getReference();
+ final EObject currentContainer;
+ if (rightToLeft) {
+ currentContainer = match.getLeft();
+ } else {
+ currentContainer = match.getRight();
+ }
+ final Comparison comparison = match.getComparison();
+ final Match valueMatch = comparison.getMatch(diff.getValue());
+
+ if (currentContainer == null) {
+ // FIXME throw exception? log? re-try to merge our requirements?
+ // one of the "required" diffs should have created our container.
+ return;
+ }
+
+ final EObject expectedValue;
+ if (valueMatch == null) {
+ // value is out of the scope... we need to look it up
+ if (reference.isMany()) {
+ final List<EObject> targetList = (List<EObject>)currentContainer.eGet(reference);
+ expectedValue = findMatchIn(comparison, targetList, diff.getValue());
+ } else {
+ // the value will not be needed anyway
+ expectedValue = null;
+ }
+ } else if (rightToLeft) {
+ expectedValue = valueMatch.getLeft();
+ } else {
+ expectedValue = valueMatch.getRight();
+ }
+
+ // We have the container, reference and value to remove. Expected value can be null when the
+ // deletion was made on both side (i.e. a pseudo delete)
+ if (reference.isContainment() && expectedValue != null) {
+ EcoreUtil.remove(expectedValue);
+ if (rightToLeft && valueMatch != null) {
+ valueMatch.setLeft(null);
+ } else if (valueMatch != null) {
+ valueMatch.setRight(null);
+ }
+ // TODO remove dangling? remove empty Match?
+ } else if (reference.isMany()) {
+ /*
+ * TODO if the same value appears twice, should we try and find the one that has actually been
+ * deleted? Can it happen? For now, remove the first occurence we find.
+ */
+ final List<EObject> targetList = (List<EObject>)currentContainer.eGet(reference);
+ targetList.remove(expectedValue);
+ } else {
+ currentContainer.eUnset(reference);
+ }
+ }
+
+ /**
+ * This will be called by the merge operations in order to reset a reference to its original value, be
+ * that the left or right side.
+ * <p>
+ * Should never be called on multi-valued references.
+ * </p>
+ *
+ * @param diff
+ * The diff we are currently merging.
+ * @param rightToLeft
+ * Tells us the direction of this merge operation.
+ */
+ protected void resetInTarget(ReferenceChange diff, boolean rightToLeft) {
+ final Match match = diff.getMatch();
+ final EReference reference = diff.getReference();
+ final EObject targetContainer;
+ if (rightToLeft) {
+ targetContainer = match.getLeft();
+ } else {
+ targetContainer = match.getRight();
+ }
+
+ final EObject originContainer;
+ if (match.getComparison().isThreeWay()) {
+ originContainer = match.getOrigin();
+ } else if (rightToLeft) {
+ originContainer = match.getRight();
+ } else {
+ originContainer = match.getLeft();
+ }
+
+ if (originContainer == null || !safeEIsSet(targetContainer, reference)
+ || !safeEIsSet(originContainer, reference)) {
+ targetContainer.eUnset(reference);
+ } else {
+ final EObject originalValue = (EObject)originContainer.eGet(reference);
+ final Match valueMatch = match.getComparison().getMatch(originalValue);
+ final EObject expectedValue;
+ if (valueMatch == null) {
+ // Value is out of the scope, use it as-is
+ expectedValue = originalValue;
+ } else if (rightToLeft) {
+ expectedValue = valueMatch.getLeft();
+ } else {
+ expectedValue = valueMatch.getRight();
+ }
+ targetContainer.eSet(reference, expectedValue);
+ }
+ }
+
+ /**
+ * Handles the equivalences of this difference.
+ * <p>
+ * Note that in certain cases, we'll merge our opposite instead of merging this diff. Specifically, we'll
+ * do that for one-to-many eOpposites : we'll merge the 'many' side instead of the 'unique' one. This
+ * allows us not to worry about the order of the references on that 'many' side.
+ * </p>
+ * <p>
+ * This is called before the merge of <code>this</code>. In short, if this returns <code>false</code>, we
+ * won't carry on merging <code>this</code> after returning.
+ * </p>
+ *
+ * @param diff
+ * The diff we are currently merging.
+ * @param rightToLeft
+ * Direction of the merge.
+ * @param monitor
+ * The monitor to use in order to report progress information.
+ * @return <code>true</code> if the current difference should still be merged after handling its
+ * equivalences, <code>false</code> if it should be considered "already merged".
+ */
+ protected boolean handleEquivalences(ReferenceChange diff, boolean rightToLeft, Monitor monitor) {
+ final EReference reference = diff.getReference();
+ boolean continueMerge = true;
+ for (Diff equivalent : diff.getEquivalence().getDifferences()) {
+ // For 1..*, merge diff on many-valued to preserve ordering
+ if (equivalent instanceof ReferenceChange
+ && reference.getEOpposite() == ((ReferenceChange)equivalent).getReference()
+ && equivalent.getState() == DifferenceState.UNRESOLVED) {
+ // This equivalence is on our eOpposite. Should we merge it instead of 'this'?
+ final boolean mergeEquivalence = !reference.isMany()
+ && ((ReferenceChange)equivalent).getReference().isMany();
+ if (mergeEquivalence) {
+ mergeDiff(equivalent, rightToLeft, monitor);
+ continueMerge = false;
+ }
+ }
+
+ /*
+ * If one of the equivalent differences is implied or implying (depending on the merge direction)
+ * a merged diff, then we have a dependency loop : the "current" difference has already been
+ * merged because of this implication. This will allow us to break out of that loop.
+ */
+ if (rightToLeft) {
+ if (diff.getSource() == DifferenceSource.LEFT) {
+ continueMerge = continueMerge
+ && !containsAny(diff.getRequiredBy(), equivalent.getImplies());
+ } else {
+ continueMerge = continueMerge
+ && !containsAny(diff.getRequires(), equivalent.getImpliedBy());
+ }
+ } else {
+ if (diff.getSource() == DifferenceSource.LEFT) {
+ continueMerge = continueMerge
+ && !containsAny(diff.getRequires(), equivalent.getImpliedBy());
+ } else {
+ continueMerge = continueMerge
+ && !containsAny(diff.getRequiredBy(), equivalent.getImplies());
+ }
+ }
+
+ equivalent.setState(DifferenceState.MERGED);
+ }
+ return continueMerge;
+ }
+
+ /**
+ * Utility method to check that the first sequence contains one of the elements of the second sequence at
+ * least.
+ *
+ * @param sequence1
+ * The first sequence.
+ * @param sequence2
+ * The second sequence.
+ * @return True if the given first sequence contains one of the elements of the second sequence at least.
+ * false otherwise.
+ */
+ private boolean containsAny(List<? extends EObject> sequence1, List<? extends EObject> sequence2) {
+ return Iterables.any(sequence2, Predicates.in(sequence1));
+ }
+
+ /**
+ * Seeks a match of the given {@code element} in the given list, using the equality helper to find it.
+ * This is only used when moving or deleting proxies for now.
+ *
+ * @param comparison
+ * The comparison which Diff we are currently merging.
+ * @param list
+ * The list from which we seek a value.
+ * @param element
+ * The value for which we need a match in {@code list}.
+ * @return The match of {@code element} in {@code list}, {@code null} if none.
+ */
+ protected EObject findMatchIn(Comparison comparison, List<EObject> list, EObject element) {
+ final IEqualityHelper helper = comparison.getEqualityHelper();
+ final Iterator<EObject> it = list.iterator();
+ while (it.hasNext()) {
+ final EObject next = it.next();
+ if (helper.matchingValues(next, element)) {
+ return next;
+ }
+ }
+ return null;
+ }
+
+ /**
+ * This will be used by the distinct merge actions in order to find the index at which a value should be
+ * inserted in its target list. See {@link DiffUtil#findInsertionIndex(Comparison, Diff, boolean)} for
+ * more on this.
+ * <p>
+ * Sub-classes can override this if the insertion order is irrelevant. A return value of {@code -1} will
+ * be considered as "no index" and the value will be inserted at the end of its target list.
+ * </p>
+ *
+ * @param comparison
+ * This will be used in order to retrieve the Match for EObjects when comparing them.
+ * @param diff
+ * The diff which merging will trigger the need for an insertion index in its target list.
+ * @param rightToLeft
+ * {@code true} if the merging will be done into the left list, so that we should consider the
+ * right model as the source and the left as the target.
+ * @return The index at which this {@code diff}'s value should be inserted into the 'target' list, as
+ * inferred from {@code rightToLeft}. {@code -1} if the value should be inserted at the end of its
+ * target list.
+ * @see DiffUtil#findInsertionIndex(Comparison, Diff, boolean)
+ */
+ protected int findInsertionIndex(Comparison comparison, Diff diff, boolean rightToLeft) {
+ return DiffUtil.findInsertionIndex(comparison, diff, rightToLeft);
+ }
+}

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