blob: 771e0735c889c4b74ee498dec627612082287c6d [file] [log] [blame]
// 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;
import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
import com.google.devtools.build.lib.profiler.Profiler;
import com.google.devtools.build.lib.profiler.ProfilerTask;
import com.google.devtools.build.lib.vfs.DigestHashFunction.DefaultHashFunctionNotSetException;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/** This class implements the FileSystem interface using direct calls to the UNIX filesystem. */
@ThreadSafe
public abstract class AbstractFileSystem extends FileSystem {
protected static final String ERR_PERMISSION_DENIED = " (Permission denied)";
protected static final Profiler profiler = Profiler.instance();
public AbstractFileSystem() throws DefaultHashFunctionNotSetException {}
public AbstractFileSystem(DigestHashFunction digestFunction) {
super(digestFunction);
}
@Override
protected InputStream getInputStream(Path path) throws IOException {
// This loop is a workaround for an apparent bug in FileInputStream.open, which delegates
// ultimately to JVM_Open in the Hotspot JVM. This call is not EINTR-safe, so we must do the
// retry here.
for (; ; ) {
try {
return createFileInputStream(path);
} catch (FileNotFoundException e) {
if (e.getMessage().endsWith("(Interrupted system call)")) {
continue;
} else {
throw e;
}
}
}
}
/** Returns either normal or profiled FileInputStream. */
private InputStream createFileInputStream(Path path) throws FileNotFoundException {
final String name = path.toString();
if (profiler.isActive()
&& (profiler.isProfiling(ProfilerTask.VFS_READ)
|| profiler.isProfiling(ProfilerTask.VFS_OPEN))) {
long startTime = Profiler.nanoTimeMaybe();
try {
// Replace default FileInputStream instance with the custom one that does profiling.
return new ProfiledFileInputStream(name);
} finally {
profiler.logSimpleTask(startTime, ProfilerTask.VFS_OPEN, name);
}
} else {
// Use normal FileInputStream instance if profiler is not enabled.
return new FileInputStream(path.toString());
}
}
/**
* Returns either normal or profiled FileOutputStream. Should be used by subclasses to create
* default OutputStream instance.
*/
protected OutputStream createFileOutputStream(Path path, boolean append)
throws FileNotFoundException {
final String name = path.toString();
if (profiler.isActive()
&& (profiler.isProfiling(ProfilerTask.VFS_WRITE)
|| profiler.isProfiling(ProfilerTask.VFS_OPEN))) {
long startTime = Profiler.nanoTimeMaybe();
try {
return new ProfiledFileOutputStream(name, append);
} finally {
profiler.logSimpleTask(startTime, ProfilerTask.VFS_OPEN, name);
}
} else {
return new FileOutputStream(name, append);
}
}
@Override
protected OutputStream getOutputStream(Path path, boolean append) throws IOException {
try {
return createFileOutputStream(path, append);
} catch (FileNotFoundException e) {
// Why does it throw a *FileNotFoundException* if it can't write?
// That does not make any sense! And its in a completely different
// format than in other situations, no less!
if (e.getMessage().equals(path + ERR_PERMISSION_DENIED)) {
throw new FileAccessException(e.getMessage());
}
throw e;
}
}
private static final class ProfiledFileInputStream extends FileInputStream {
private final String name;
public ProfiledFileInputStream(String name) throws FileNotFoundException {
super(name);
this.name = name;
}
@Override
public int read() throws IOException {
long startTime = Profiler.nanoTimeMaybe();
try {
// Note that FileInputStream#read() does *not* call any of our overridden methods,
// so there's no concern with double counting here.
return super.read();
} finally {
profiler.logSimpleTask(startTime, ProfilerTask.VFS_READ, name);
}
}
@Override
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
long startTime = Profiler.nanoTimeMaybe();
try {
return super.read(b, off, len);
} finally {
profiler.logSimpleTask(startTime, ProfilerTask.VFS_READ, name);
}
}
}
private static final class ProfiledFileOutputStream extends FileOutputStream {
private final String name;
public ProfiledFileOutputStream(String name, boolean append) throws FileNotFoundException {
super(name, append);
this.name = name;
}
@Override
public void write(byte[] b) throws IOException {
write(b, 0, b.length);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
long startTime = Profiler.nanoTimeMaybe();
try {
super.write(b, off, len);
} finally {
profiler.logSimpleTask(startTime, ProfilerTask.VFS_WRITE, name);
}
}
}
}