io.permazen.kv.raft.NewLogEntry Maven / Gradle / Ivy
/*
* Copyright (C) 2015 Archie L. Cobbs. All rights reserved.
*/
package io.permazen.kv.raft;
import com.google.common.base.Preconditions;
import java.io.File;
import java.io.IOException;
/**
* Contains the information required to commit a new entry to the log.
*
*
* Instances must be {@link #close}'ed when no longer needed to ensure the temporary file is deleted if not used.
*/
class NewLogEntry {
private final LogEntry.Data data;
private final File tempFile;
private boolean tempFileReset;
/**
* Create an instance from a local transaction and an existing temporary file.
*
* @param tx local transaction
* @param tempFile temporary file containing serialized mutations
*/
NewLogEntry(RaftKVTransaction tx, File tempFile) throws IOException {
this(new LogEntry.Data(tx.view.getWrites(), tx.getConfigChange()), tempFile);
}
/**
* Create an instance from a local transaction. A corresponding temporary file will be created automatically.
*
* @param tx local transaction
*/
NewLogEntry(RaftKVTransaction tx) throws IOException {
this(tx.raft, new LogEntry.Data(tx.view.getWrites(), tx.getConfigChange()));
}
/**
* Create an instance from a {@link LogEntry.Data} object. A corresponding temporary file will be created automatically.
*
* @param raft database
* @param data mutation data
* @throws IOException if an I/O error occurs
*/
NewLogEntry(RaftKVDatabase raft, LogEntry.Data data) throws IOException {
this(data, NewLogEntry.writeDataToFile(data, raft, raft.disableSync));
}
/**
* Create an instance from a {@link LogEntry.Data} object and an existing temporary file.
*
* @param data mutation data
* @param tempFile temporary file containing serialized mutations
*/
NewLogEntry(LogEntry.Data data, File tempFile) {
assert data != null;
assert tempFile != null;
this.data = data;
this.tempFile = tempFile;
}
public LogEntry.Data getData() {
return this.data;
}
public File getTempFile() {
Preconditions.checkState(!this.tempFileReset);
return this.tempFile;
}
public void resetTempFile() {
assert !this.tempFile.exists();
this.tempFileReset = true;
}
public void cleanup(RaftKVDatabase raft) {
if (!this.tempFileReset)
raft.deleteFile(this.tempFile, "new log entry temp file");
}
private static File writeDataToFile(LogEntry.Data data, RaftKVDatabase raft, boolean disableSync) throws IOException {
final File tempFile = raft.getTempFile();
boolean success = false;
try (FileWriter output = new FileWriter(tempFile, disableSync)) {
LogEntry.writeData(output, data);
success = true;
} finally {
if (!success)
raft.deleteFile(tempFile, "new log entry temp file");
}
return tempFile;
}
}