Bug 536282 - Check whether processing step is availableI20181220-1800

Extend ProcessingStep with isEnabled() method that checks if step's
dependencies are available. ProcessingStepHandler's canProcess will
ensure that all required processing steps are enabled and skip this
check for optional processing steps.

MirrorRequest's perform(IArtifactRepository, IProgressMonitor) method
will skip optimized artifact if it can't be processed and chose
canonical one.

Pack200ProcessorStep's isEnabled() checks if 'unpack200' CLI utility
is available by calling UnpackStep's canUnpack().

Change-Id: I048db3b833f6e0881cca06ad48be37ad6d17a0c9
Signed-off-by: Mykola Nikishov <mn@mn.com.ua>

3 files changed, 66 insertions, 10 deletions

diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/processors/pack200/Pack200ProcessorStep.java b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/processors/pack200/Pack200ProcessorStep.java
index 7eb071752..c088e95ed 100644
--- a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/processors/pack200/Pack200ProcessorStep.java
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/processors/pack200/Pack200ProcessorStep.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2017 compeople AG and others.
+ * Copyright (c) 2007, 2018 compeople AG and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -11,6 +11,7 @@
  * Contributors:
  * 	compeople AG (Stefan Liebig) - initial API and implementation
  *  IBM Corporation - ongoing development
+*   Mykola Nikishov - continuing development
  *******************************************************************************/
 package org.eclipse.equinox.internal.p2.artifact.processors.pack200;
 
@@ -47,7 +48,7 @@ public class Pack200ProcessorStep extends AbstractBufferingStep {
 	@Override
 	public void initialize(IProvisioningAgent agent, IProcessingStepDescriptor descriptor, IArtifactDescriptor context) {
 		super.initialize(agent, descriptor, context);
-		if (!UnpackStep.canUnpack()) {
+		if (!isEnabled()) {
 			IStatus status = null;
 			if (detailedResult) {
 				status = new Status(IStatus.ERROR, Activator.ID, MirrorRequest.ARTIFACT_PROCESSING_ERROR, "Unpack facility not configured.", null); //$NON-NLS-1$
@@ -103,4 +104,9 @@ public class Pack200ProcessorStep extends AbstractBufferingStep {
 		new JarProcessorExecutor().runJarProcessor(options);
 		return new File(getWorkDir(), incoming.getName().substring(0, incoming.getName().length() - PACKED_SUFFIX.length()));
 	}
+
+	@Override
+	public boolean isEnabled() {
+		return UnpackStep.canUnpack();
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/provisional/p2/artifact/repository/processing/ProcessingStep.java b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/provisional/p2/artifact/repository/processing/ProcessingStep.java
index 734a5482a..b32c1cfee 100644
--- a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/provisional/p2/artifact/repository/processing/ProcessingStep.java
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/provisional/p2/artifact/repository/processing/ProcessingStep.java
@@ -11,6 +11,7 @@
 * Contributors:
 * 	compeople AG (Stefan Liebig) - initial API and implementation
 *   IBM Corporation - continuing development
+*   Mykola Nikishov - continuing development
 *******************************************************************************/
 package org.eclipse.equinox.internal.provisional.p2.artifact.repository.processing;
 
@@ -133,4 +134,16 @@ public abstract class ProcessingStep extends OutputStream implements IStateful {
 	public IStatus getStatus(boolean deep) {
 		return ProcessingStepHandler.getStatus(this, deep);
 	}
+
+	/**
+	 * If step has dependencies that may come and go during application's
+	 * lifetime (i.e., user may uninstall CLI utility that step depended on),
+	 * this method checks if such dependencies are available.
+	 *
+	 * @return if step's dependencies are satisfied
+	 * @since 1.3
+	 */
+	public boolean isEnabled() {
+		return true;
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/provisional/p2/artifact/repository/processing/ProcessingStepHandler.java b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/provisional/p2/artifact/repository/processing/ProcessingStepHandler.java
index 25a099eb6..adc2fc484 100644
--- a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/provisional/p2/artifact/repository/processing/ProcessingStepHandler.java
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/provisional/p2/artifact/repository/processing/ProcessingStepHandler.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
-* Copyright (c) 2007, 2017 compeople AG and others.
+* Copyright (c) 2007, 2018 compeople AG and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
@@ -11,14 +11,21 @@
 * Contributors:
 * 	compeople AG (Stefan Liebig) - initial API and implementation
 *  IBM - continuing development
+*  Mykola Nikishov - continuing development
 *******************************************************************************/
 package org.eclipse.equinox.internal.provisional.p2.artifact.repository.processing;
 
+import static java.util.Arrays.stream;
+import static java.util.Optional.ofNullable;
+import static java.util.stream.Collectors.toList;
+
 import java.io.OutputStream;
 import java.util.ArrayList;
+import java.util.List;
 import org.eclipse.core.runtime.*;
 import org.eclipse.equinox.internal.p2.artifact.repository.Activator;
 import org.eclipse.equinox.internal.p2.artifact.repository.simple.SimpleArtifactRepository.ArtifactOutputStream;
+import org.eclipse.equinox.internal.p2.core.helpers.LogHelper;
 import org.eclipse.equinox.internal.provisional.p2.repository.IStateful;
 import org.eclipse.equinox.p2.core.IProvisioningAgent;
 import org.eclipse.equinox.p2.repository.artifact.IArtifactDescriptor;
@@ -38,19 +45,49 @@ public class ProcessingStepHandler {
 	}
 
 	/**
-	 * Check to see that we have processors for all the steps in the given descriptor
+	 * Check to see that we have processors for all required steps in the given descriptor
 	 * @param descriptor the descriptor to check
 	 * @return whether or not processors for all the descriptor's steps are installed
+	 * @see IProcessingStepDescriptor#isRequired()
 	 */
 	public static boolean canProcess(IArtifactDescriptor descriptor) {
-		IExtensionRegistry registry = RegistryFactory.getRegistry();
-		IExtensionPoint point = registry.getExtensionPoint(PROCESSING_STEPS_EXTENSION_ID);
+		IExtensionPoint point = ofNullable(RegistryFactory.getRegistry())
+			.map(r -> r.getExtensionPoint(PROCESSING_STEPS_EXTENSION_ID))
+			.orElse(null);
 		if (point == null)
 			return false;
-		IProcessingStepDescriptor[] steps = descriptor.getProcessingSteps();
-		for (int i = 0; i < steps.length; i++) {
-			if (point.getExtension(steps[i].getProcessorId()) == null)
-				return false;
+
+		List<String> processorIds = stream(descriptor.getProcessingSteps())
+			// ignore steps that are not required
+			.filter(IProcessingStepDescriptor::isRequired)
+			.map(IProcessingStepDescriptor::getProcessorId)
+			.collect(toList());
+		try {
+			for (String processorId : processorIds) {
+				IExtension requiredExtension = point.getExtension(processorId);
+				if (requiredExtension == null)
+					return false;
+
+				List<IConfigurationElement> stepConfigs = stream(requiredExtension.getConfigurationElements())
+					// skip anything but step elements
+					.filter(config -> "step".equals(config.getName())) //$NON-NLS-1$
+					.collect(toList());
+				if (stepConfigs.size() != 1)
+					// do not tolerate no or multiple step elements
+					return false;
+
+				IConfigurationElement stepConfig = stepConfigs.get(0);
+				ProcessingStep stepToCheck = (ProcessingStep) stepConfig.createExecutableExtension("class"); //$NON-NLS-1$
+				if (!stepToCheck.isEnabled())
+					return false;
+			}
+		} catch (InvalidRegistryObjectException e) {
+			// extension is no longer valid, log and ignore
+			LogHelper.log(new Status(IStatus.WARNING, Activator.ID, "", e)); //$NON-NLS-1$
+			return false;
+		} catch (CoreException e) {
+			// unable to instantiate an extension, already logged, ignore
+			return false;
 		}
 		return true;
 	}