1 files changed, 112 insertions, 0 deletions
diff --git a/bundles/org.eclipse.equinox.p2.engine/src/org/eclipse/equinox/internal/provisional/p2/engine/EngineSession.java b/bundles/org.eclipse.equinox.p2.engine/src/org/eclipse/equinox/internal/provisional/p2/engine/EngineSession.java
new file mode 100644
index 000000000..b01c40294
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.engine/src/org/eclipse/equinox/internal/provisional/p2/engine/EngineSession.java
@@ -0,0 +1,112 @@
+/*******************************************************************************
+ * Copyright (c) 2007 IBM Corporation and others.
+ * 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:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.internal.provisional.p2.engine;
+
+import java.util.*;
+import org.eclipse.core.runtime.*;
+import org.eclipse.equinox.internal.p2.engine.EngineActivator;
+
+public class EngineSession {
+
+	private static class ActionsRecord {
+		InstallableUnitOperand operand;
+		List actions = new ArrayList();
+
+		ActionsRecord(InstallableUnitOperand operand) {
+			this.operand = operand;
+		}
+	}
+
+	private List phaseActionRecordsPairs = new ArrayList();
+
+	private Phase currentPhase;
+	private List currentActionRecords;
+	private ActionsRecord currentRecord;
+
+	private IProfile profile;
+
+	public EngineSession(IProfile profile) {
+		this.profile = profile;
+	}
+
+	public void commit() {
+		phaseActionRecordsPairs.clear();
+	}
+
+	public MultiStatus rollback() {
+		MultiStatus result = new MultiStatus(EngineActivator.ID, IStatus.OK, null, null);
+		if (currentPhase != null) {
+			rollBackPhase(currentPhase, currentActionRecords);
+			currentPhase = null;
+			currentActionRecords = null;
+			currentRecord = null;
+		}
+
+		for (ListIterator it = phaseActionRecordsPairs.listIterator(phaseActionRecordsPairs.size()); it.hasPrevious();) {
+			Object[] pair = (Object[]) it.previous();
+			Phase phase = (Phase) pair[0];
+			List actionRecords = (List) pair[1];
+			rollBackPhase(phase, actionRecords);
+		}
+		phaseActionRecordsPairs.clear();
+		return result;
+	}
+
+	private MultiStatus rollBackPhase(Phase phase, List actionRecords) {
+		MultiStatus result = new MultiStatus(EngineActivator.ID, IStatus.OK, null, null);
+
+		if (phase != currentPhase)
+			phase.prePerform(result, profile, new NullProgressMonitor());
+
+		for (ListIterator it = actionRecords.listIterator(actionRecords.size()); it.hasPrevious();) {
+			ActionsRecord record = (ActionsRecord) it.previous();
+			ProvisioningAction[] actions = (ProvisioningAction[]) record.actions.toArray(new ProvisioningAction[record.actions.size()]);
+			phase.undo(result, this, profile, record.operand, actions);
+		}
+		phase.postPerform(result, profile, new NullProgressMonitor());
+		return result;
+	}
+
+	void recordPhaseStart(Phase phase) {
+		if (phase == null)
+			throw new IllegalArgumentException("Phase must not be null."); //$NON-NLS-1$
+
+		if (currentPhase != null)
+			throw new IllegalStateException("A phase is already started."); //$NON-NLS-1$
+
+		currentPhase = phase;
+		currentActionRecords = new ArrayList();
+	}
+
+	void recordPhaseEnd(Phase phase) {
+		if (currentPhase == null)
+			throw new IllegalStateException("There is no phase to end."); //$NON-NLS-1$
+
+		if (currentPhase != phase)
+			throw new IllegalArgumentException("Current phase does not match argument."); //$NON-NLS-1$
+
+		phaseActionRecordsPairs.add(new Object[] {currentPhase, currentActionRecords});
+		currentPhase = null;
+		currentActionRecords = null;
+		currentRecord = null;
+	}
+
+	void recordAction(ProvisioningAction action, InstallableUnitOperand operand) {
+		if (action == null || operand == null)
+			throw new IllegalArgumentException("Action and InstallableUnitOperand must not be null."); //$NON-NLS-1$
+
+		if (currentRecord == null || operand != currentRecord.operand) {
+			currentRecord = new ActionsRecord(operand);
+			currentActionRecords.add(currentRecord);
+		}
+		currentRecord.actions.add(action);
+	}
+}