Merge pull request #1168 from lucamilanesio/bump-to-lucene-5.5.2

Bump to Lucene 5.5.2

The new code will create Lucene indices in a new directory named after codec and index version.
This provides for easy and safe up- and downgrades. But it also means that the old indices will
stick around on disk. What this version is missing is a kind of "garbage collection" deleting old, unused
indices when they are no longer needed. That task needs to be done manually currently. We should
at leas at some point provide a script for it.

1 files changed, 98 insertions, 0 deletions

diff --git a/src/main/java/com/gitblit/utils/LuceneIndexStore.java b/src/main/java/com/gitblit/utils/LuceneIndexStore.java
new file mode 100644
index 00000000..c05e2019
--- /dev/null
+++ b/src/main/java/com/gitblit/utils/LuceneIndexStore.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright 2017 gitblit.com.
+ *
+ * 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 com.gitblit.utils;
+
+import java.io.File;
+import java.nio.file.Path;
+
+/**
+ * @author Florian Zschocke
+ *
+ * @since 1.9.0
+ */
+public class LuceneIndexStore
+{
+
+	public static final int LUCENE_CODEC_VERSION = 54;
+
+	protected File indexFolder;
+
+	/**
+	 * Constructor for a base folder that contains the version specific index folders
+	 * and an index version.
+	 *
+	 * @param luceneFolder
+	 * 			Path to the base folder for the Lucene indices, i.e. the common "lucene" directory.
+	 * @param indexVersion
+	 * 			Version of the index definition
+	 */
+	public LuceneIndexStore(File luceneFolder, int indexVersion)
+	{
+		this.indexFolder = new File(luceneFolder, indexVersion + "_" + LUCENE_CODEC_VERSION);
+	}
+
+
+
+	/**
+	 * Create the Lucene index directory for this index version and Lucene codec version
+	 */
+	public void create()
+	{
+		if (! indexFolder.exists()) {
+			indexFolder.mkdirs();
+		}
+	}
+
+
+	/**
+	 * Delete the Lucene index directory for this index version and Lucene codec version
+	 *
+	 * @return	True if the directory could successfully be deleted.
+	 */
+	public boolean delete()
+	{
+		if (indexFolder.exists()) {
+			return FileUtils.delete(indexFolder);
+		}
+		return true;
+	}
+
+
+
+	/**
+	 * @return	The Path to the index folder
+	 */
+	public Path getPath()
+	{
+		return indexFolder.toPath();
+	}
+
+
+
+	/**
+	 * Check if an index of the respective version, or compatible, already exists.
+	 *
+	 * @return	True if an index exists, False otherwise
+	 */
+	public boolean hasIndex()
+	{
+		return indexFolder.exists() &&
+				indexFolder.isDirectory() &&
+				(indexFolder.list().length > 1);  // Must have more than 'write.lock'
+	}
+
+}