/*
* SonarQube
* Copyright (C) 2009-2017 SonarSource SA
* mailto:info AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.sonar.home.cache;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import javax.annotation.CheckForNull;
/**
* This class is responsible for managing Sonar batch file cache. You can put file into cache and
* later try to retrieve them. MD5 is used to differentiate files (name is not secure as files may come
* from different Sonar servers and have same name but be actually different, and same for SNAPSHOTs).
*/
public class FileCache {
/** Maximum loop count when creating temp directories. */
private static final int TEMP_DIR_ATTEMPTS = 10_000;
private final File dir;
private final File tmpDir;
private final FileHashes hashes;
private final Logger logger;
FileCache(File dir, FileHashes fileHashes, Logger logger) {
this.hashes = fileHashes;
this.logger = logger;
this.dir = createDir(dir, "user cache");
logger.info(String.format("User cache: %s", dir.getAbsolutePath()));
this.tmpDir = createDir(new File(dir, "_tmp"), "temp dir");
}
public static FileCache create(File dir, Logger logger) {
return new FileCache(dir, new FileHashes(), logger);
}
public File getDir() {
return dir;
}
/**
* Look for a file in the cache by its filename and md5 checksum. If the file is not
* present then return null.
*/
@CheckForNull
public File get(String filename, String hash) {
File cachedFile = new File(new File(dir, hash), filename);
if (cachedFile.exists()) {
return cachedFile;
}
logger.debug(String.format("No file found in the cache with name %s and hash %s", filename, hash));
return null;
}
public interface Downloader {
void download(String filename, File toFile) throws IOException;
}
public File get(String filename, String hash, Downloader downloader) {
// Does not fail if another process tries to create the directory at the same time.
File hashDir = hashDir(hash);
File targetFile = new File(hashDir, filename);
if (!targetFile.exists()) {
File tempFile = newTempFile();
download(downloader, filename, tempFile);
String downloadedHash = hashes.of(tempFile);
if (!hash.equals(downloadedHash)) {
throw new IllegalStateException("INVALID HASH: File " + tempFile.getAbsolutePath() + " was expected to have hash " + hash
+ " but was downloaded with hash " + downloadedHash);
}
mkdirQuietly(hashDir);
renameQuietly(tempFile, targetFile);
}
return targetFile;
}
private static void download(Downloader downloader, String filename, File tempFile) {
try {
downloader.download(filename, tempFile);
} catch (IOException e) {
throw new IllegalStateException("Fail to download " + filename + " to " + tempFile, e);
}
}
private void renameQuietly(File sourceFile, File targetFile) {
boolean rename = sourceFile.renameTo(targetFile);
// Check if the file was cached by another process during download
if (!rename && !targetFile.exists()) {
logger.warn(String.format("Unable to rename %s to %s", sourceFile.getAbsolutePath(), targetFile.getAbsolutePath()));
logger.warn("A copy/delete will be tempted but with no guarantee of atomicity");
try {
Files.move(sourceFile.toPath(), targetFile.toPath());
} catch (IOException e) {
throw new IllegalStateException("Fail to move " + sourceFile.getAbsolutePath() + " to " + targetFile, e);
}
}
}
private File hashDir(String hash) {
return new File(dir, hash);
}
private static void mkdirQuietly(File hashDir) {
try {
Files.createDirectories(hashDir.toPath());
} catch (IOException e) {
throw new IllegalStateException("Fail to create cache directory: " + hashDir, e);
}
}
private File newTempFile() {
try {
return File.createTempFile("fileCache", null, tmpDir);
} catch (IOException e) {
throw new IllegalStateException("Fail to create temp file in " + tmpDir, e);
}
}
public File createTempDir() {
String baseName = System.currentTimeMillis() + "-";
for (int counter = 0; counter < TEMP_DIR_ATTEMPTS; counter++) {
File tempDir = new File(tmpDir, baseName + counter);
if (tempDir.mkdir()) {
return tempDir;
}
}
throw new IllegalStateException("Failed to create directory in " + tmpDir);
}
private File createDir(File dir, String debugTitle) {
if (!dir.isDirectory() || !dir.exists()) {
logger.debug("Create : " + dir.getAbsolutePath());
try {
Files.createDirectories(dir.toPath());
} catch (IOException e) {
throw new IllegalStateException("Unable to create " + debugTitle + dir.getAbsolutePath(), e);
}
}
return dir;
}
}