db: Import db/commmitlog/*

Signed-off-by: Calle Wilund <calle@cloudius-systems.com>

db/commitlog/CommitLogDescriptor.java

@@ -0,0 +1,168 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.cassandra.db.commitlog;
+
+import java.io.EOFException;
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import com.google.common.annotations.VisibleForTesting;
+import org.apache.cassandra.io.FSReadError;
+import org.apache.cassandra.net.MessagingService;
+import org.apache.cassandra.utils.PureJavaCrc32;
+
+public class CommitLogDescriptor
+{
+    private static final String SEPARATOR = "-";
+    private static final String FILENAME_PREFIX = "CommitLog" + SEPARATOR;
+    private static final String FILENAME_EXTENSION = ".log";
+    // match both legacy and new version of commitlogs Ex: CommitLog-12345.log and CommitLog-4-12345.log.
+    private static final Pattern COMMIT_LOG_FILE_PATTERN = Pattern.compile(FILENAME_PREFIX + "((\\d+)(" + SEPARATOR + "\\d+)?)" + FILENAME_EXTENSION);
+
+    public static final int VERSION_12 = 2;
+    public static final int VERSION_20 = 3;
+    public static final int VERSION_21 = 4;
+    public static final int VERSION_30 = 5;
+    /**
+     * Increment this number if there is a changes in the commit log disc layout or MessagingVersion changes.
+     * Note: make sure to handle {@link #getMessagingVersion()}
+     */
+    @VisibleForTesting
+    public static final int current_version = VERSION_30;
+
+    // [version, id, checksum]
+    static final int HEADER_SIZE = 4 + 8 + 4;
+
+    final int version;
+    public final long id;
+
+    public CommitLogDescriptor(int version, long id)
+    {
+        this.version = version;
+        this.id = id;
+    }
+
+    public CommitLogDescriptor(long id)
+    {
+        this(current_version, id);
+    }
+
+    static void writeHeader(ByteBuffer out, CommitLogDescriptor descriptor)
+    {
+        out.putInt(0, descriptor.version);
+        out.putLong(4, descriptor.id);
+        PureJavaCrc32 crc = new PureJavaCrc32();
+        crc.updateInt(descriptor.version);
+        crc.updateInt((int) (descriptor.id & 0xFFFFFFFFL));
+        crc.updateInt((int) (descriptor.id >>> 32));
+        out.putInt(12, crc.getCrc());
+    }
+
+    public static CommitLogDescriptor fromHeader(File file)
+    {
+        try (RandomAccessFile raf = new RandomAccessFile(file, "r"))
+        {
+            assert raf.getFilePointer() == 0;
+            int version = raf.readInt();
+            long id = raf.readLong();
+            int crc = raf.readInt();
+            PureJavaCrc32 checkcrc = new PureJavaCrc32();
+            checkcrc.updateInt(version);
+            checkcrc.updateInt((int) (id & 0xFFFFFFFFL));
+            checkcrc.updateInt((int) (id >>> 32));
+            if (crc == checkcrc.getCrc())
+                return new CommitLogDescriptor(version, id);
+            return null;
+        }
+        catch (EOFException e)
+        {
+            throw new RuntimeException(e);
+        }
+        catch (IOException e)
+        {
+            throw new FSReadError(e, file);
+        }
+    }
+
+    public static CommitLogDescriptor fromFileName(String name)
+    {
+        Matcher matcher;
+        if (!(matcher = COMMIT_LOG_FILE_PATTERN.matcher(name)).matches())
+            throw new RuntimeException("Cannot parse the version of the file: " + name);
+
+        if (matcher.group(3) == null)
+            throw new UnsupportedOperationException("Commitlog segment is too old to open; upgrade to 1.2.5+ first");
+
+        long id = Long.parseLong(matcher.group(3).split(SEPARATOR)[1]);
+        return new CommitLogDescriptor(Integer.parseInt(matcher.group(2)), id);
+    }
+
+    public int getMessagingVersion()
+    {
+        switch (version)
+        {
+            case VERSION_12:
+                return MessagingService.VERSION_12;
+            case VERSION_20:
+                return MessagingService.VERSION_20;
+            case VERSION_21:
+                return MessagingService.VERSION_21;
+            case VERSION_30:
+                return MessagingService.VERSION_30;
+            default:
+                throw new IllegalStateException("Unknown commitlog version " + version);
+        }
+    }
+
+    public String fileName()
+    {
+        return FILENAME_PREFIX + version + SEPARATOR + id + FILENAME_EXTENSION;
+    }
+
+    /**
+     * @param   filename  the filename to check
+     * @return true if filename could be a commit log based on it's filename
+     */
+    public static boolean isValid(String filename)
+    {
+        return COMMIT_LOG_FILE_PATTERN.matcher(filename).matches();
+    }
+
+    public String toString()
+    {
+        return "(" + version + "," + id + ")";
+    }
+
+    public boolean equals(Object that)
+    {
+        return that instanceof CommitLogDescriptor && equals((CommitLogDescriptor) that);
+    }
+
+    public boolean equals(CommitLogDescriptor that)
+    {
+        return this.version == that.version && this.id == that.id;
+    }
+
+}