diff options
Diffstat (limited to 'jimfs/src/main/java/com/google/common/jimfs/JimfsInputStream.java')
-rw-r--r-- | jimfs/src/main/java/com/google/common/jimfs/JimfsInputStream.java | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/jimfs/src/main/java/com/google/common/jimfs/JimfsInputStream.java b/jimfs/src/main/java/com/google/common/jimfs/JimfsInputStream.java new file mode 100644 index 0000000..750530c --- /dev/null +++ b/jimfs/src/main/java/com/google/common/jimfs/JimfsInputStream.java @@ -0,0 +1,158 @@ +/* + * Copyright 2013 Google Inc. + * + * 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.common.jimfs; + +import static com.google.common.base.Preconditions.checkNotNull; +import static com.google.common.base.Preconditions.checkPositionIndexes; + +import com.google.common.annotations.VisibleForTesting; +import com.google.common.primitives.Ints; +import java.io.IOException; +import java.io.InputStream; + +/** + * {@link InputStream} for reading from a file's {@link RegularFile}. + * + * @author Colin Decker + */ +final class JimfsInputStream extends InputStream { + + @GuardedBy("this") + @VisibleForTesting + RegularFile file; + + @GuardedBy("this") + private long pos; + + @GuardedBy("this") + private boolean finished; + + private final FileSystemState fileSystemState; + + public JimfsInputStream(RegularFile file, FileSystemState fileSystemState) { + this.file = checkNotNull(file); + this.fileSystemState = fileSystemState; + fileSystemState.register(this); + } + + @Override + public synchronized int read() throws IOException { + checkNotClosed(); + if (finished) { + return -1; + } + + file.readLock().lock(); + try { + + int b = file.read(pos++); // it's ok for pos to go beyond size() + if (b == -1) { + finished = true; + } else { + file.updateAccessTime(); + } + return b; + } finally { + file.readLock().unlock(); + } + } + + @Override + public int read(byte[] b) throws IOException { + return readInternal(b, 0, b.length); + } + + @Override + public int read(byte[] b, int off, int len) throws IOException { + checkPositionIndexes(off, off + len, b.length); + return readInternal(b, off, len); + } + + private synchronized int readInternal(byte[] b, int off, int len) throws IOException { + checkNotClosed(); + if (finished) { + return -1; + } + + file.readLock().lock(); + try { + int read = file.read(pos, b, off, len); + if (read == -1) { + finished = true; + } else { + pos += read; + } + + file.updateAccessTime(); + return read; + } finally { + file.readLock().unlock(); + } + } + + @Override + public long skip(long n) throws IOException { + if (n <= 0) { + return 0; + } + + synchronized (this) { + checkNotClosed(); + if (finished) { + return 0; + } + + // available() must be an int, so the min must be also + int skip = (int) Math.min(Math.max(file.size() - pos, 0), n); + pos += skip; + return skip; + } + } + + @Override + public synchronized int available() throws IOException { + checkNotClosed(); + if (finished) { + return 0; + } + long available = Math.max(file.size() - pos, 0); + return Ints.saturatedCast(available); + } + + @GuardedBy("this") + private void checkNotClosed() throws IOException { + if (file == null) { + throw new IOException("stream is closed"); + } + } + + @Override + public synchronized void close() throws IOException { + if (isOpen()) { + fileSystemState.unregister(this); + file.closed(); + + // file is set to null here and only here + file = null; + } + } + + @GuardedBy("this") + private boolean isOpen() { + return file != null; + } +} |