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// Copyright 2015 Google Inc. All Rights Reserved.
//
// 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.gitiles.doc;
import static javax.servlet.http.HttpServletResponse.SC_NOT_MODIFIED;
import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
import static org.eclipse.jgit.lib.FileMode.TYPE_FILE;
import static org.eclipse.jgit.lib.FileMode.TYPE_MASK;
import static org.eclipse.jgit.lib.FileMode.TYPE_TREE;
import com.google.common.base.MoreObjects;
import com.google.common.base.Strings;
import com.google.common.base.Throwables;
import com.google.common.hash.Hasher;
import com.google.common.hash.Hashing;
import com.google.common.net.HttpHeaders;
import com.google.gitiles.BaseServlet;
import com.google.gitiles.GitilesAccess;
import com.google.gitiles.GitilesRequestFailureException;
import com.google.gitiles.GitilesRequestFailureException.FailureReason;
import com.google.gitiles.GitilesView;
import com.google.gitiles.Renderer;
import com.google.gitiles.ViewFilter;
import com.google.gitiles.doc.html.StreamHtmlBuilder;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;
import javax.annotation.Nullable;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.commonmark.node.Node;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.LargeObjectException;
import org.eclipse.jgit.http.server.ServletUtils;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.TreeWalk;
public class DocServlet extends BaseServlet {
private static final long serialVersionUID = 1L;
private static final String INDEX_MD = "index.md";
private static final String NAVBAR_MD = "navbar.md";
private static final String SOY_FILE = "Doc.soy";
private static final String SOY_TEMPLATE = "gitiles.markdownDoc";
// Generation of ETag logic. Bump this only if DocServlet logic changes
// significantly enough to impact cached pages. Soy template and source
// files are automatically hashed as part of the ETag.
private static final int ETAG_GEN = 5;
private final HtmlSanitizer.Factory htmlSanitizer;
public DocServlet(GitilesAccess.Factory accessFactory, Renderer renderer) {
this(accessFactory, renderer, HtmlSanitizer.DISABLED_FACTORY);
}
public DocServlet(
GitilesAccess.Factory accessFactory, Renderer renderer, HtmlSanitizer.Factory htmlSanitizer) {
super(renderer, accessFactory);
this.htmlSanitizer = htmlSanitizer;
}
@Override
protected void doGetHtml(HttpServletRequest req, HttpServletResponse res) throws IOException {
MarkdownConfig cfg = MarkdownConfig.get(getAccess(req).getConfig());
if (!cfg.render) {
throw new GitilesRequestFailureException(FailureReason.MARKDOWN_NOT_ENABLED);
}
GitilesView view = ViewFilter.getView(req);
Repository repo = ServletUtils.getRepository(req);
try (RevWalk rw = new RevWalk(repo)) {
ObjectReader reader = rw.getObjectReader();
String path = view.getPathPart();
RevTree root;
try {
root = rw.parseTree(view.getRevision().getId());
} catch (IncorrectObjectTypeException e) {
throw new GitilesRequestFailureException(FailureReason.INCORRECT_OBJECT_TYPE);
}
MarkdownFile srcmd = findFile(rw, root, path);
if (srcmd == null) {
throw new GitilesRequestFailureException(FailureReason.OBJECT_NOT_FOUND);
}
MarkdownFile navmd = findNavbar(rw, root, path);
String curEtag = etag(srcmd, navmd);
if (etagMatch(req, curEtag)) {
res.setStatus(SC_NOT_MODIFIED);
return;
}
view = view.toBuilder().setPathPart(srcmd.path).build();
try {
srcmd.read(reader, cfg);
if (navmd != null) {
navmd.read(reader, cfg);
}
} catch (LargeObjectException.ExceedsLimit e) {
fileTooBig(res, view);
return;
}
MarkdownToHtml.Builder fmt =
MarkdownToHtml.builder()
.setConfig(cfg)
.setGitilesView(view)
.setRequestUri(req.getRequestURI())
.setReader(reader)
.setRootTree(root)
.setHtmlSanitizer(htmlSanitizer.create(req));
Navbar navbar = createNavbar(cfg, fmt, navmd);
res.setHeader(HttpHeaders.ETAG, curEtag);
showDoc(req, res, view, fmt, navbar, srcmd);
}
}
private static boolean etagMatch(HttpServletRequest req, String etag) {
String reqEtag = req.getHeader(HttpHeaders.IF_NONE_MATCH);
return reqEtag != null && reqEtag.equals(etag);
}
private String etag(MarkdownFile srcmd, @Nullable MarkdownFile navmd) {
byte[] b = new byte[Constants.OBJECT_ID_LENGTH];
Hasher h = Hashing.murmur3_128().newHasher();
h.putInt(ETAG_GEN);
renderer.getTemplateHash(SOY_FILE).writeBytesTo(b, 0, b.length);
h.putBytes(b);
if (navmd != null) {
navmd.id.copyRawTo(b, 0);
h.putBytes(b);
}
srcmd.id.copyRawTo(b, 0);
h.putBytes(b);
return h.hash().toString();
}
private MarkdownFile findNavbar(RevWalk rw, RevTree root, String path) throws IOException {
if (!Strings.isNullOrEmpty(path)) {
// Traverse up the path until we find a NAVBAR_MD.
StringBuilder pathRemaining = new StringBuilder(path);
while (pathRemaining.length() > 0) {
int lastPathSeparatorIndex = pathRemaining.lastIndexOf("/");
pathRemaining.setLength(lastPathSeparatorIndex + 1);
MarkdownFile navmd = findFile(rw, root, pathRemaining.toString() + NAVBAR_MD);
if (navmd != null) {
return navmd;
}
pathRemaining.setLength(Math.max(lastPathSeparatorIndex, 0));
}
return null;
}
return findFile(rw, root, NAVBAR_MD);
}
private void showDoc(
HttpServletRequest req,
HttpServletResponse res,
GitilesView view,
MarkdownToHtml.Builder fmt,
Navbar navbar,
MarkdownFile srcFile)
throws IOException {
Map<String, Object> data = new HashMap<>();
data.putAll(navbar.toSoyData());
MarkdownConfig cfg = navbar.getConfig();
Node doc = GitilesMarkdown.parse(cfg, srcFile.consumeContent());
data.put("pageTitle", pageTitle(doc, srcFile));
if (view.getType() != GitilesView.Type.ROOTED_DOC) {
data.put("sourceUrl", GitilesView.show().copyFrom(view).toUrl());
data.put("logUrl", GitilesView.log().copyFrom(view).toUrl());
data.put("blameUrl", GitilesView.blame().copyFrom(view).toUrl());
}
if (cfg.analyticsId != null) {
data.put("analyticsId", cfg.analyticsId);
}
try (OutputStream out = startRenderCompressedStreamingHtml(req, res, SOY_TEMPLATE, data)) {
Writer w = newWriter(out, res);
fmt.setConfig(cfg)
.setFilePath(srcFile.path)
.build()
.renderToHtml(new StreamHtmlBuilder(w), doc);
w.flush();
} catch (RuntimeIOException e) {
Throwables.throwIfInstanceOf(e.getCause(), IOException.class);
throw e;
}
}
private static Navbar createNavbar(
MarkdownConfig cfg, MarkdownToHtml.Builder fmt, @Nullable MarkdownFile navFile) {
Navbar navbar = new Navbar().setConfig(cfg);
if (navFile != null) {
navbar
.setFormatter(fmt.setFilePath(navFile.path).build())
.setMarkdown(navFile.consumeContent());
}
return navbar;
}
private static String pageTitle(Node doc, MarkdownFile srcFile) {
String title = MarkdownUtil.getTitle(doc);
return MoreObjects.firstNonNull(title, srcFile.path);
}
@Nullable
private static MarkdownFile findFile(RevWalk rw, RevTree root, String path) throws IOException {
if (Strings.isNullOrEmpty(path)) {
path = INDEX_MD;
}
ObjectReader reader = rw.getObjectReader();
try (TreeWalk tw = TreeWalk.forPath(reader, path, root)) {
if (tw == null) {
return null;
}
if ((tw.getRawMode(0) & TYPE_MASK) == TYPE_TREE) {
if (findIndexFile(tw)) {
path = tw.getPathString();
} else {
return null;
}
}
if ((tw.getRawMode(0) & TYPE_MASK) == TYPE_FILE) {
if (!path.endsWith(".md")) {
return null;
}
return new MarkdownFile(path, tw.getObjectId(0));
}
return null;
}
}
private static boolean findIndexFile(TreeWalk tw) throws IOException {
tw.enterSubtree();
while (tw.next()) {
if ((tw.getRawMode(0) & TYPE_MASK) == TYPE_FILE && INDEX_MD.equals(tw.getNameString())) {
return true;
}
}
return false;
}
private static void fileTooBig(HttpServletResponse res, GitilesView view) throws IOException {
if (view.getType() == GitilesView.Type.ROOTED_DOC) {
throw new GitilesRequestFailureException(FailureReason.OBJECT_TOO_LARGE);
} else {
res.sendRedirect(GitilesView.show().copyFrom(view).toUrl());
}
}
private static class MarkdownFile {
final String path;
final ObjectId id;
byte[] content;
MarkdownFile(String path, ObjectId id) {
this.path = path;
this.id = id;
}
void read(ObjectReader reader, MarkdownConfig cfg) throws IOException {
content = reader.open(id, OBJ_BLOB).getCachedBytes(cfg.inputLimit);
}
byte[] consumeContent() {
byte[] c = content;
content = null;
return c;
}
}
}