1 files changed, 74 insertions, 0 deletions
diff --git a/bundles/org.eclipse.equinox.p2.touchpoint.eclipse/src/org/eclipse/equinox/internal/p2/update/ConfigurationIO.java b/bundles/org.eclipse.equinox.p2.touchpoint.eclipse/src/org/eclipse/equinox/internal/p2/update/ConfigurationIO.java
new file mode 100644
index 000000000..44dfae151
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.touchpoint.eclipse/src/org/eclipse/equinox/internal/p2/update/ConfigurationIO.java
@@ -0,0 +1,74 @@
+/*******************************************************************************
+ * Copyright (c) 2009 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.p2.update;
+
+import java.io.File;
+import java.net.URL;
+import org.eclipse.equinox.p2.core.ProvisionException;
+
+/*
+ * Class which controls the reading and writing of Configuration (platform.xml) objects.
+ * We keep a local cached copy to avoid multiple reads. When we install new features we
+ * seem to only write out the platform.xml in the "commit" phase so we don't need to 
+ * batch the writes.
+ */
+public class ConfigurationIO {
+	private static CacheEntry cache = null;
+
+	// class used to represent cache values
+	static class CacheEntry {
+		Configuration config;
+		URL osgiInstallArea;
+		File location;
+		long timestamp;
+	}
+
+	/*
+	 * Return the configuration object which is represented by the given file. 
+	 */
+	static Configuration read(File file, URL osgiInstallArea) throws ProvisionException {
+		// check the cached copy first
+		if (cache != null && file.lastModified() == cache.timestamp)
+			return cache.config;
+
+		// cache miss or file is out of date, read from disk
+		Configuration config = ConfigurationParser.parse(file, osgiInstallArea);
+		if (config == null)
+			return null;
+
+		// successful read, store in the cache before we return
+		cache(file, config, osgiInstallArea);
+		return config;
+	}
+
+	/*
+	 * Store the given configuration file in the local cache.
+	 */
+	private static void cache(File location, Configuration config, URL osgiInstallArea) {
+		CacheEntry entry = new CacheEntry();
+		entry.config = config;
+		entry.osgiInstallArea = osgiInstallArea;
+		entry.location = location;
+		entry.timestamp = location.lastModified();
+		cache = entry;
+	}
+
+	/*
+	 * Save the given configuration to the file-system.
+	 */
+	static void write(File location, Configuration config, URL osgiInstallArea) throws ProvisionException {
+		// write it to disk 
+		ConfigurationWriter.save(config, location, osgiInstallArea);
+		// save a copy in the cache
+		cache(location, config, osgiInstallArea);
+	}
+
+}