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- /*
- * Copyright (C) 2010, Google Inc. and others
- *
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Distribution License v. 1.0 which is available at
- * https://www.eclipse.org/org/documents/edl-v10.php.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
- package org.eclipse.jgit.http.server;
-
- import static org.eclipse.jgit.http.server.ServletUtils.acceptsGzipEncoding;
- import static org.eclipse.jgit.util.HttpSupport.ENCODING_GZIP;
- import static org.eclipse.jgit.util.HttpSupport.HDR_CONTENT_ENCODING;
-
- import java.io.IOException;
- import java.io.OutputStream;
- import java.util.zip.GZIPOutputStream;
-
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
-
- import org.eclipse.jgit.util.TemporaryBuffer;
-
- /**
- * Buffers a response, trying to gzip it if the user agent supports that.
- * <p>
- * If the response overflows the buffer, gzip is skipped and the response is
- * streamed to the client as its produced, most likely using HTTP/1.1 chunked
- * encoding. This is useful for servlets that produce mixed-mode content, where
- * smaller payloads are primarily pure text that compresses well, while much
- * larger payloads are heavily compressed binary data. {@link UploadPackServlet}
- * is one such servlet.
- */
- class SmartOutputStream extends TemporaryBuffer {
- private static final int LIMIT = 32 * 1024;
-
- private final HttpServletRequest req;
- private final HttpServletResponse rsp;
- private boolean compressStream;
- private boolean startedOutput;
-
- SmartOutputStream(final HttpServletRequest req,
- final HttpServletResponse rsp,
- boolean compressStream) {
- super(LIMIT);
- this.req = req;
- this.rsp = rsp;
- this.compressStream = compressStream;
- }
-
- /** {@inheritDoc} */
- @Override
- protected OutputStream overflow() throws IOException {
- startedOutput = true;
-
- OutputStream out = rsp.getOutputStream();
- if (compressStream && acceptsGzipEncoding(req)) {
- rsp.setHeader(HDR_CONTENT_ENCODING, ENCODING_GZIP);
- out = new GZIPOutputStream(out);
- }
- return out;
- }
-
- /** {@inheritDoc} */
- @Override
- public void close() throws IOException {
- super.close();
-
- if (!startedOutput) {
- // If output hasn't started yet, the entire thing fit into our
- // buffer. Try to use a proper Content-Length header, and also
- // deflate the response with gzip if it will be smaller.
- @SuppressWarnings("resource")
- TemporaryBuffer out = this;
-
- if (256 < out.length() && acceptsGzipEncoding(req)) {
- TemporaryBuffer gzbuf = new TemporaryBuffer.Heap(LIMIT);
- try {
- try (GZIPOutputStream gzip = new GZIPOutputStream(gzbuf)) {
- out.writeTo(gzip, null);
- }
- if (gzbuf.length() < out.length()) {
- out = gzbuf;
- rsp.setHeader(HDR_CONTENT_ENCODING, ENCODING_GZIP);
- }
- } catch (IOException err) {
- // Most likely caused by overflowing the buffer, meaning
- // its larger if it were compressed. Discard compressed
- // copy and use the original.
- }
- }
-
- // The Content-Length cannot overflow when cast to an int, our
- // hardcoded LIMIT constant above assures us we wouldn't store
- // more than 2 GiB of content in memory.
- rsp.setContentLength((int) out.length());
- try (OutputStream os = rsp.getOutputStream()) {
- out.writeTo(os, null);
- os.flush();
- }
- }
- }
- }
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