| // 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.unix.FileAccessException; |
| |
| 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 |
| abstract class AbstractFileSystem extends FileSystem { |
| |
| protected static final String ERR_PERMISSION_DENIED = " (Permission denied)"; |
| protected static final Profiler profiler = Profiler.instance(); |
| |
| @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 FileInputStream(name) { |
| @Override public int read() throws IOException { |
| long startTime = Profiler.nanoTimeMaybe(); |
| try { |
| // Note that FileInputStream#read() does *not* call any of our overriden 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); |
| } |
| } |
| }; |
| } 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 FileOutputStream(name, append) { |
| @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); |
| } |
| } |
| }; |
| } finally { |
| profiler.logSimpleTask(startTime, ProfilerTask.VFS_OPEN, name); |
| } |
| } else { |
| return new FileOutputStream(name, append); |
| } |
| } |
| |
| @Override |
| protected OutputStream getOutputStream(Path path, boolean append) throws IOException { |
| synchronized (path) { |
| 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; |
| } |
| } |
| } |
| } |