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;
+  }
+}