// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.vfs.util;
import com.google.common.base.Verify;
import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
import com.google.devtools.build.lib.testutil.TestConstants;
import com.google.devtools.build.lib.unix.UnixFileSystem;
import com.google.devtools.build.lib.util.OS;
import com.google.devtools.build.lib.vfs.FileSystem;
import com.google.devtools.build.lib.vfs.JavaIoFileSystem;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.lib.vfs.UnionFileSystem;
import com.google.devtools.build.lib.vfs.ZipFileSystem;
import com.google.devtools.build.lib.windows.WindowsFileSystem;
import java.io.IOException;
import java.util.Map;
/**
* This static file system singleton manages access to a single default
* {@link FileSystem} instance created within the methods of this class.
*/
@ThreadSafe
public final class FileSystems {
private FileSystems() {}
private static FileSystem defaultNativeFileSystem;
private static FileSystem defaultJavaIoFileSystem;
private static FileSystem defaultUnionFileSystem;
/**
* Initializes the default native {@link FileSystem} instance as a platform native
* (Unix or Windows) file system. If it's not initialized, then initialize it,
* otherwise verify if the type of the instance is correct.
*/
public static synchronized FileSystem getNativeFileSystem() {
if (OS.getCurrent() == OS.WINDOWS) {
if (defaultNativeFileSystem == null) {
defaultNativeFileSystem = new WindowsFileSystem();
} else {
Verify.verify(defaultNativeFileSystem instanceof WindowsFileSystem);
}
} else {
if (defaultNativeFileSystem == null) {
try {
defaultNativeFileSystem = (FileSystem)
Class.forName(TestConstants.TEST_REAL_UNIX_FILE_SYSTEM)
.getDeclaredConstructor().newInstance();
} catch (Exception e) {
throw new IllegalStateException(e);
}
} else {
Verify.verify(defaultNativeFileSystem instanceof UnixFileSystem);
}
}
return defaultNativeFileSystem;
}
/**
* Initializes the default java {@link FileSystem} instance as a java.io.File
* file system. If it's not initialized, then initialize it,
* otherwise verify if the type of the instance is correct.
*/
public static synchronized FileSystem getJavaIoFileSystem() {
if (defaultJavaIoFileSystem == null) {
defaultJavaIoFileSystem = new JavaIoFileSystem();
} else {
Verify.verify(defaultJavaIoFileSystem instanceof JavaIoFileSystem);
}
return defaultJavaIoFileSystem;
}
/**
* Initializes the default union {@link FileSystem} instance as a
* {@link UnionFileSystem}. If it's not initialized, then initialize it,
* otherwise verify if the type of the instance is correct.
*
* @param prefixMapping the desired mapping of path prefixes to delegate file systems
* @param rootFileSystem the default file system for paths that don't match any prefix map
*/
public static synchronized FileSystem getUnionFileSystem(
Map<PathFragment, FileSystem> prefixMapping, FileSystem rootFileSystem) {
if (defaultUnionFileSystem == null) {
defaultUnionFileSystem = new UnionFileSystem(prefixMapping, rootFileSystem);
} else {
Verify.verify(defaultUnionFileSystem instanceof UnionFileSystem);
}
return defaultUnionFileSystem;
}
/**
* Returns a new instance of a simple {@link FileSystem} implementation that
* presents the contents of a zip file as a read-only file system view.
*/
public static FileSystem getZipFileSystem(Path zipFile) throws IOException {
return new ZipFileSystem(zipFile);
}
}