java/com/google/gitiles/doc/DocServlet.java - gitiles - Git at Google

 // 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, e);
       }

       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);
     }
     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;
     }
   }
 }
	// 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, e);
	}

	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);
	}
	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;
	}
	}
	}