1 files changed, 68 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/ioutil/LimitedByteArrayOutputStream.java b/java/com/google/gerrit/server/ioutil/LimitedByteArrayOutputStream.java
new file mode 100644
index 0000000000..015887bb35
--- /dev/null
+++ b/java/com/google/gerrit/server/ioutil/LimitedByteArrayOutputStream.java
@@ -0,0 +1,68 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// 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.gerrit.server.ioutil;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+
+/** A stream that throws an exception if it consumes data beyond a configured byte count. */
+public class LimitedByteArrayOutputStream extends OutputStream {
+
+  private final int maxSize;
+  private final ByteArrayOutputStream buffer;
+
+  /**
+   * Constructs a LimitedByteArrayOutputStream, which stores output in memory up to a certain
+   * specified size. When the output exceeds the specified size a LimitExceededException is thrown.
+   *
+   * @param max the maximum size in bytes which may be stored.
+   * @param initial the initial size. It must be smaller than the max size.
+   */
+  public LimitedByteArrayOutputStream(int max, int initial) {
+    checkArgument(initial <= max);
+    maxSize = max;
+    buffer = new ByteArrayOutputStream(initial);
+  }
+
+  private void checkOversize(int additionalSize) throws IOException {
+    if (buffer.size() + additionalSize > maxSize) {
+      throw new LimitExceededException();
+    }
+  }
+
+  @Override
+  public void write(int b) throws IOException {
+    checkOversize(1);
+    buffer.write(b);
+  }
+
+  @Override
+  public void write(byte[] b, int off, int len) throws IOException {
+    checkOversize(len);
+    buffer.write(b, off, len);
+  }
+
+  /** @return a newly allocated byte array with contents of the buffer. */
+  public byte[] toByteArray() {
+    return buffer.toByteArray();
+  }
+
+  public static class LimitExceededException extends IOException {
+    private static final long serialVersionUID = 1L;
+  }
+}