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/*
* Copyright (C) 2009-2010, 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 jakarta.servlet.http.HttpServletResponse.SC_PARTIAL_CONTENT;
import static jakarta.servlet.http.HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE;
import static org.eclipse.jgit.util.HttpSupport.HDR_ACCEPT_RANGES;
import static org.eclipse.jgit.util.HttpSupport.HDR_CONTENT_LENGTH;
import static org.eclipse.jgit.util.HttpSupport.HDR_CONTENT_RANGE;
import static org.eclipse.jgit.util.HttpSupport.HDR_IF_RANGE;
import static org.eclipse.jgit.util.HttpSupport.HDR_RANGE;
import java.io.EOFException;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.text.MessageFormat;
import java.time.Instant;
import java.util.Enumeration;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.util.FS;
/**
* Dumps a file over HTTP GET (or its information via HEAD).
* <p>
* Supports a single byte range requested via {@code Range} HTTP header. This
* feature supports a dumb client to resume download of a larger object file.
*/
final class FileSender {
private final File path;
private final RandomAccessFile source;
private final Instant lastModified;
private final long fileLen;
private long pos;
private long end;
FileSender(File path) throws FileNotFoundException {
this.path = path;
this.source = new RandomAccessFile(path, "r");
try {
this.lastModified = FS.DETECTED.lastModifiedInstant(path);
this.fileLen = source.getChannel().size();
this.end = fileLen;
} catch (IOException e) {
try {
source.close();
} catch (IOException closeError) {
// Ignore any error closing the stream.
}
final FileNotFoundException r;
r = new FileNotFoundException(MessageFormat.format(HttpServerText.get().cannotGetLengthOf, path));
r.initCause(e);
throw r;
}
}
void close() {
try {
source.close();
} catch (IOException e) {
// Ignore close errors on a read-only stream.
}
}
Instant getLastModified() {
return lastModified;
}
String getTailChecksum() throws IOException {
final int n = 20;
final byte[] buf = new byte[n];
source.seek(fileLen - n);
source.readFully(buf, 0, n);
return ObjectId.fromRaw(buf).getName();
}
void serve(final HttpServletRequest req, final HttpServletResponse rsp,
final boolean sendBody) throws IOException {
if (!initRangeRequest(req, rsp)) {
rsp.sendError(SC_REQUESTED_RANGE_NOT_SATISFIABLE);
return;
}
rsp.setHeader(HDR_ACCEPT_RANGES, "bytes");
rsp.setHeader(HDR_CONTENT_LENGTH, Long.toString(end - pos));
if (sendBody) {
try (OutputStream out = rsp.getOutputStream()) {
final byte[] buf = new byte[4096];
source.seek(pos);
while (pos < end) {
final int r = (int) Math.min(buf.length, end - pos);
final int n = source.read(buf, 0, r);
if (n < 0) {
throw new EOFException(MessageFormat.format(HttpServerText.get().unexpectedeOFOn, path));
}
out.write(buf, 0, n);
pos += n;
}
out.flush();
}
}
}
private boolean initRangeRequest(final HttpServletRequest req,
final HttpServletResponse rsp) throws IOException {
final Enumeration<String> rangeHeaders = getRange(req);
if (!rangeHeaders.hasMoreElements()) {
// No range headers, the request is fine.
return true;
}
final String range = rangeHeaders.nextElement();
if (rangeHeaders.hasMoreElements()) {
// To simplify the code we support only one range.
return false;
}
final int eq = range.indexOf('=');
final int dash = range.indexOf('-');
if (eq < 0 || dash < 0 || !range.startsWith("bytes=")) {
return false;
}
final String ifRange = req.getHeader(HDR_IF_RANGE);
if (ifRange != null && !getTailChecksum().equals(ifRange)) {
// If the client asked us to verify the ETag and its not
// what they expected we need to send the entire content.
return true;
}
try {
if (eq + 1 == dash) {
// "bytes=-500" means last 500 bytes
pos = Long.parseLong(range.substring(dash + 1));
pos = fileLen - pos;
} else {
// "bytes=500-" (position 500 to end)
// "bytes=500-1000" (position 500 to 1000)
pos = Long.parseLong(range.substring(eq + 1, dash));
if (dash < range.length() - 1) {
end = Long.parseLong(range.substring(dash + 1));
end++; // range was inclusive, want exclusive
}
}
} catch (NumberFormatException e) {
// We probably hit here because of a non-digit such as
// "," appearing at the end of the first range telling
// us there is a second range following. To simplify
// the code we support only one range.
return false;
}
if (end > fileLen) {
end = fileLen;
}
if (pos >= end) {
return false;
}
rsp.setStatus(SC_PARTIAL_CONTENT);
rsp.setHeader(HDR_CONTENT_RANGE, "bytes " + pos + "-" + (end - 1) + "/"
+ fileLen);
source.seek(pos);
return true;
}
private static Enumeration<String> getRange(HttpServletRequest req) {
return req.getHeaders(HDR_RANGE);
}
}
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