java/com/google/gitiles/doc/MarkdownToHtml.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 com.google.gitiles.doc.MarkdownUtil.getInnerText;

 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Strings;
 import com.google.common.html.types.SafeHtml;
 import com.google.gitiles.GitilesView;
 import com.google.gitiles.ThreadSafePrettifyParser;
 import com.google.gitiles.doc.html.HtmlBuilder;
 import com.google.gitiles.doc.html.SoyHtmlBuilder;
 import java.util.List;
 import javax.annotation.Nullable;
 import org.commonmark.ext.gfm.strikethrough.Strikethrough;
 import org.commonmark.ext.gfm.tables.TableBlock;
 import org.commonmark.ext.gfm.tables.TableBody;
 import org.commonmark.ext.gfm.tables.TableCell;
 import org.commonmark.ext.gfm.tables.TableHead;
 import org.commonmark.ext.gfm.tables.TableRow;
 import org.commonmark.node.Block;
 import org.commonmark.node.BlockQuote;
 import org.commonmark.node.BulletList;
 import org.commonmark.node.Code;
 import org.commonmark.node.CustomBlock;
 import org.commonmark.node.CustomNode;
 import org.commonmark.node.Document;
 import org.commonmark.node.Emphasis;
 import org.commonmark.node.FencedCodeBlock;
 import org.commonmark.node.HardLineBreak;
 import org.commonmark.node.Heading;
 import org.commonmark.node.HtmlBlock;
 import org.commonmark.node.HtmlInline;
 import org.commonmark.node.Image;
 import org.commonmark.node.IndentedCodeBlock;
 import org.commonmark.node.Link;
 import org.commonmark.node.ListBlock;
 import org.commonmark.node.ListItem;
 import org.commonmark.node.Node;
 import org.commonmark.node.OrderedList;
 import org.commonmark.node.Paragraph;
 import org.commonmark.node.SoftLineBreak;
 import org.commonmark.node.StrongEmphasis;
 import org.commonmark.node.Text;
 import org.commonmark.node.ThematicBreak;
 import org.commonmark.node.Visitor;
 import org.eclipse.jgit.lib.ObjectReader;
 import org.eclipse.jgit.revwalk.RevTree;
 import prettify.parser.Prettify;
 import syntaxhighlight.ParseResult;

 /**
  * Formats parsed Markdown AST into HTML.
  *
  * <p>Callers must create a new instance for each document.
  */
 public class MarkdownToHtml implements Visitor {
   public static Builder builder() {
     return new Builder();
   }

   public static class Builder {
     private String requestUri;
     private GitilesView view;
     private MarkdownConfig config;
     private String filePath;
     private ObjectReader reader;
     private RevTree root;
     private HtmlSanitizer htmlSanitizer = HtmlSanitizer.DISABLED;

     Builder() {}

     public Builder setRequestUri(@Nullable String uri) {
       requestUri = uri;
       return this;
     }

     public Builder setGitilesView(@Nullable GitilesView view) {
       this.view = view;
       return this;
     }

     public Builder setConfig(@Nullable MarkdownConfig config) {
       this.config = config;
       return this;
     }

     public Builder setFilePath(@Nullable String filePath) {
       this.filePath = Strings.emptyToNull(filePath);
       return this;
     }

     public Builder setReader(ObjectReader reader) {
       this.reader = reader;
       return this;
     }

     public Builder setRootTree(RevTree tree) {
       this.root = tree;
       return this;
     }

     public Builder setHtmlSanitizer(HtmlSanitizer htmlSanitizer) {
       this.htmlSanitizer = MoreObjects.firstNonNull(htmlSanitizer, HtmlSanitizer.DISABLED);
       return this;
     }

     public MarkdownToHtml build() {
       return new MarkdownToHtml(this);
     }
   }

   private HtmlBuilder html;
   private TocFormatter toc;
   private final String requestUri;
   private final GitilesView view;
   private final MarkdownConfig config;
   private final String filePath;
   private final HtmlSanitizer htmlSanitizer;
   private final ImageLoader imageLoader;
   private boolean outputNamedAnchor = true;

   protected MarkdownToHtml(Builder b) {
     requestUri = b.requestUri;
     view = b.view;
     config = b.config;
     filePath = b.filePath;
     htmlSanitizer = b.htmlSanitizer;
     imageLoader = newImageLoader(b);
   }

   protected HtmlBuilder html() {
     return html;
   }

   private static ImageLoader newImageLoader(Builder b) {
     if (b.reader != null && b.view != null && b.config != null && b.root != null) {
       return new ImageLoader(b.reader, b.view, b.config, b.root);
     }
     return null;
   }

   /** Render the document AST to sanitized HTML. */
   public void renderToHtml(HtmlBuilder out, Node node) {
     if (node != null) {
       html = out;
       toc = new TocFormatter(html, 3);
       toc.setRoot(node);
       node.accept(this);
       html.finish();
       html = null;
       toc = null;
     }
   }

   /** Render the document AST to sanitized HTML. */
   public SafeHtml toSoyHtml(Node node) {
     if (node != null) {
       SoyHtmlBuilder out = new SoyHtmlBuilder();
       renderToHtml(out, node);
       return out.toSoy();
     }
     return null;
   }

   @Override
   public void visit(Document node) {
     visitChildren(node);
   }

   private void visit(BlockNote node) {
     html.open("div").attribute("class", node.getClassName());
     Node f = node.getFirstChild();
     if (f == node.getLastChild() && f instanceof Paragraph) {
       // Avoid <p> inside <div> if there is only one <p>.
       visitChildren(f);
     } else {
       visitChildren(node);
     }
     html.close("div");
   }

   private void visit(MultiColumnBlock node) {
     html.open("div").attribute("class", "cols");
     visitChildren(node);
     html.close("div");
   }

   private void visit(MultiColumnBlock.Column node) {
     if (1 <= node.span && node.span <= MultiColumnBlock.GRID_WIDTH) {
       html.open("div").attribute("class", "col-" + node.span);
       visitChildren(node);
       html.close("div");
     }
   }

   private void visit(IframeBlock node) {
     if (HtmlBuilder.isValidHttpUri(node.src)
         && HtmlBuilder.isValidCssDimension(node.height)
         && HtmlBuilder.isValidCssDimension(node.width)
         && config != null
         && config.isIFrameAllowed(node.src)) {
       html.open("iframe")
           .attribute("src", node.src)
           .attribute("height", node.height)
           .attribute("width", node.width);
       if (!node.border) {
         html.attribute("class", "noborder");
       }
       html.close("iframe");
     }
   }

   @Override
   public void visit(Heading node) {
     outputNamedAnchor = false;
     String tag = "h" + node.getLevel();
     html.open(tag);
     String id = toc.idFromHeader(node);
     if (id != null) {
       html.open("a")
           .attribute("class", "h")
           .attribute("name", id)
           .attribute("href", "#" + id)
           .open("span")
           .close("span")
           .close("a");
       // github markdown compatibility
       if (!id.equals(id.toLowerCase())) {
         html.open("a")
             .attribute("class", "h")
             .attribute("name", id.toLowerCase())
             .attribute("href", "#" + id.toLowerCase())
             .open("span")
             .close("span")
             .close("a");
       }
     }
     visitChildren(node);
     html.close(tag);
     outputNamedAnchor = true;
   }

   private void visit(NamedAnchor node) {
     if (outputNamedAnchor) {
       html.open("a").attribute("name", node.getName()).close("a");
     }
   }

   @Override
   public void visit(Paragraph node) {
     if (isInTightList(node)) {
       // Avoid unnecessary <p> tags within <ol><li> structures.
       visitChildren(node);
     } else {
       wrapChildren("p", node);
     }
   }

   private static boolean isInTightList(Paragraph c) {
     Block b = c.getParent(); // b is probably a ListItem
     if (b != null) {
       Block a = b.getParent();
       return a instanceof ListBlock && ((ListBlock) a).isTight();
     }
     return false;
   }

   @Override
   public void visit(BlockQuote node) {
     wrapChildren("blockquote", node);
   }

   @Override
   public void visit(OrderedList node) {
     html.open("ol");
     if (node.getStartNumber() != 1) {
       html.attribute("start", Integer.toString(node.getStartNumber()));
     }
     visitChildren(node);
     html.close("ol");
   }

   @Override
   public void visit(BulletList node) {
     wrapChildren("ul", node);
   }

   @Override
   public void visit(ListItem node) {
     wrapChildren("li", node);
   }

   @Override
   public void visit(FencedCodeBlock node) {
     codeInPre(node.getInfo(), node.getLiteral());
   }

   @Override
   public void visit(IndentedCodeBlock node) {
     codeInPre(null, node.getLiteral());
   }

   private void codeInPre(String lang, String text) {
     html.open("pre").attribute("class", "code");
     text = printLeadingBlankLines(text);
     List<ParseResult> parsed = parse(lang, text);
     if (parsed != null) {
       int last = 0;
       for (ParseResult r : parsed) {
         span(null, text, last, r.getOffset());
         last = r.getOffset() + r.getLength();
         span(r.getStyleKeysString(), text, r.getOffset(), last);
       }
       if (last < text.length()) {
         span(null, text, last, text.length());
       }
     } else {
       html.appendAndEscape(text);
     }
     html.close("pre");
   }

   private String printLeadingBlankLines(String text) {
     int i = 0;
     while (i < text.length() && text.charAt(i) == '\n') {
       html.open("br");
       i++;
     }
     return text.substring(i);
   }

   private void span(String classes, String s, int start, int end) {
     if (end - start > 0) {
       if (Strings.isNullOrEmpty(classes)) {
         classes = Prettify.PR_PLAIN;
       }
       html.open("span").attribute("class", classes);
       html.appendAndEscape(s.substring(start, end));
       html.close("span");
     }
   }

   private List<ParseResult> parse(@Nullable String lang, String text) {
     if (Strings.isNullOrEmpty(lang)) {
       return null;
     }
     try {
       return ThreadSafePrettifyParser.INSTANCE.parse(lang, text);
     } catch (StackOverflowError e) {
       return null;
     }
   }

   @Override
   public void visit(Code node) {
     html.open("code").attribute("class", "code").appendAndEscape(node.getLiteral()).close("code");
   }

   @Override
   public void visit(Emphasis node) {
     wrapChildren("em", node);
   }

   @Override
   public void visit(StrongEmphasis node) {
     wrapChildren("strong", node);
   }

   @Override
   public void visit(Link node) {
     html.open("a")
         .attribute("href", href(node.getDestination()))
         .attribute("title", node.getTitle());
     visitChildren(node);
     html.close("a");
   }

   @VisibleForTesting
   String href(String target) {
     if (target.startsWith("#")
         || HtmlBuilder.isValidHttpUri(target)
         || HtmlBuilder.isValidMailtoUri(target)) {
       return target;
     } else if (target.startsWith("git:")) {
       if (HtmlBuilder.isValidGitUri(target)) {
         return target;
       }
       return SoyConstants.NORMAL_URI_INNOCUOUS_OUTPUT;
     }

     String anchor = "";
     int hash = target.indexOf('#');
     if (hash >= 0) {
       anchor = target.substring(hash);
       target = target.substring(0, hash);
     }

     String dest = PathResolver.resolve(filePath, target);
     if (dest == null || view == null) {
       return SoyConstants.NORMAL_URI_INNOCUOUS_OUTPUT;
     }

     GitilesView.Builder b;
     if (view.getType() == GitilesView.Type.ROOTED_DOC) {
       b = GitilesView.rootedDoc();
     } else {
       b = GitilesView.path();
     }
     dest = b.copyFrom(view).setPathPart(dest).build().toUrl();

     return PathResolver.relative(requestUri, dest) + anchor;
   }

   @Override
   public void visit(Image node) {
     html.open("img")
         .attribute("src", image(node.getDestination()))
         .attribute("title", node.getTitle())
         .attribute("alt", getInnerText(node));
   }

   String image(String dest) {
     if (HtmlBuilder.isValidHttpUri(dest) || HtmlBuilder.isImageDataUri(dest)) {
       return dest;
     } else if (imageLoader != null) {
       return imageLoader.inline(filePath, dest);
     }
     return SoyConstants.IMAGE_URI_INNOCUOUS_OUTPUT;
   }

   public void visit(TableBlock node) {
     wrapChildren("table", node);
   }

   private void visit(TableRow node) {
     wrapChildren("tr", node);
   }

   private void visit(TableCell cell) {
     String tag = cell.isHeader() ? "th" : "td";
     html.open(tag);
     TableCell.Alignment alignment = cell.getAlignment();
     if (alignment != null) {
       html.attribute("align", toHtml(alignment));
     }
     visitChildren(cell);
     html.close(tag);
   }

   private static String toHtml(TableCell.Alignment alignment) {
     switch (alignment) {
       case LEFT:
         return "left";
       case CENTER:
         return "center";
       case RIGHT:
         return "right";
       default:
         throw new IllegalArgumentException("unsupported alignment " + alignment);
     }
   }

   private void visit(SmartQuoted node) {
     switch (node.getType()) {
       case DOUBLE:
         html.entity("&ldquo;");
         visitChildren(node);
         html.entity("&rdquo;");
         break;
       case SINGLE:
         html.entity("&lsquo;");
         visitChildren(node);
         html.entity("&rsquo;");
         break;
       default:
         throw new IllegalArgumentException("unsupported quote " + node.getType());
     }
   }

   @Override
   public void visit(Text node) {
     html.appendAndEscape(node.getLiteral());
   }

   @Override
   public void visit(SoftLineBreak node) {
     html.space();
   }

   @Override
   public void visit(HardLineBreak node) {
     html.open("br");
   }

   @Override
   public void visit(ThematicBreak thematicBreak) {
     html.open("hr");
   }

   @Override
   public void visit(HtmlInline node) {
     // Discard inline HTML, as it's always partial tags.
   }

   @Override
   public void visit(HtmlBlock node) {
     html.append(htmlSanitizer.sanitize(node.getLiteral()));
   }

   private void wrapChildren(String tag, Node node) {
     html.open(tag);
     visitChildren(node);
     html.close(tag);
   }

   private void visitChildren(Node node) {
     for (Node c = node.getFirstChild(); c != null; c = c.getNext()) {
       c.accept(this);
     }
   }

   @Override
   public void visit(CustomNode node) {
     if (node instanceof NamedAnchor) {
       visit((NamedAnchor) node);
     } else if (node instanceof SmartQuoted) {
       visit((SmartQuoted) node);
     } else if (node instanceof Strikethrough) {
       wrapChildren("del", node);
     } else if (node instanceof TableBody) {
       wrapChildren("tbody", node);
     } else if (node instanceof TableCell) {
       visit((TableCell) node);
     } else if (node instanceof TableHead) {
       wrapChildren("thead", node);
     } else if (node instanceof TableRow) {
       visit((TableRow) node);
     } else {
       throw new IllegalArgumentException("cannot render " + node.getClass());
     }
   }

   @Override
   public void visit(CustomBlock node) {
     if (node instanceof BlockNote) {
       visit((BlockNote) node);
     } else if (node instanceof IframeBlock) {
       visit((IframeBlock) node);
     } else if (node instanceof MultiColumnBlock) {
       visit((MultiColumnBlock) node);
     } else if (node instanceof MultiColumnBlock.Column) {
       visit((MultiColumnBlock.Column) node);
     } else if (node instanceof TableBlock) {
       visit((TableBlock) node);
     } else if (node instanceof TocBlock) {
       toc.format();
     } else {
       throw new IllegalArgumentException("cannot render " + node.getClass());
     }
   }
 }
	// 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 com.google.gitiles.doc.MarkdownUtil.getInnerText;

	import com.google.common.annotations.VisibleForTesting;
	import com.google.common.base.MoreObjects;
	import com.google.common.base.Strings;
	import com.google.common.html.types.SafeHtml;
	import com.google.gitiles.GitilesView;
	import com.google.gitiles.ThreadSafePrettifyParser;
	import com.google.gitiles.doc.html.HtmlBuilder;
	import com.google.gitiles.doc.html.SoyHtmlBuilder;
	import java.util.List;
	import javax.annotation.Nullable;
	import org.commonmark.ext.gfm.strikethrough.Strikethrough;
	import org.commonmark.ext.gfm.tables.TableBlock;
	import org.commonmark.ext.gfm.tables.TableBody;
	import org.commonmark.ext.gfm.tables.TableCell;
	import org.commonmark.ext.gfm.tables.TableHead;
	import org.commonmark.ext.gfm.tables.TableRow;
	import org.commonmark.node.Block;
	import org.commonmark.node.BlockQuote;
	import org.commonmark.node.BulletList;
	import org.commonmark.node.Code;
	import org.commonmark.node.CustomBlock;
	import org.commonmark.node.CustomNode;
	import org.commonmark.node.Document;
	import org.commonmark.node.Emphasis;
	import org.commonmark.node.FencedCodeBlock;
	import org.commonmark.node.HardLineBreak;
	import org.commonmark.node.Heading;
	import org.commonmark.node.HtmlBlock;
	import org.commonmark.node.HtmlInline;
	import org.commonmark.node.Image;
	import org.commonmark.node.IndentedCodeBlock;
	import org.commonmark.node.Link;
	import org.commonmark.node.ListBlock;
	import org.commonmark.node.ListItem;
	import org.commonmark.node.Node;
	import org.commonmark.node.OrderedList;
	import org.commonmark.node.Paragraph;
	import org.commonmark.node.SoftLineBreak;
	import org.commonmark.node.StrongEmphasis;
	import org.commonmark.node.Text;
	import org.commonmark.node.ThematicBreak;
	import org.commonmark.node.Visitor;
	import org.eclipse.jgit.lib.ObjectReader;
	import org.eclipse.jgit.revwalk.RevTree;
	import prettify.parser.Prettify;
	import syntaxhighlight.ParseResult;

	/**
	* Formats parsed Markdown AST into HTML.
	*
	* <p>Callers must create a new instance for each document.
	*/
	public class MarkdownToHtml implements Visitor {
	public static Builder builder() {
	return new Builder();
	}

	public static class Builder {
	private String requestUri;
	private GitilesView view;
	private MarkdownConfig config;
	private String filePath;
	private ObjectReader reader;
	private RevTree root;
	private HtmlSanitizer htmlSanitizer = HtmlSanitizer.DISABLED;

	Builder() {}

	public Builder setRequestUri(@Nullable String uri) {
	requestUri = uri;
	return this;
	}

	public Builder setGitilesView(@Nullable GitilesView view) {
	this.view = view;
	return this;
	}

	public Builder setConfig(@Nullable MarkdownConfig config) {
	this.config = config;
	return this;
	}

	public Builder setFilePath(@Nullable String filePath) {
	this.filePath = Strings.emptyToNull(filePath);
	return this;
	}

	public Builder setReader(ObjectReader reader) {
	this.reader = reader;
	return this;
	}

	public Builder setRootTree(RevTree tree) {
	this.root = tree;
	return this;
	}

	public Builder setHtmlSanitizer(HtmlSanitizer htmlSanitizer) {
	this.htmlSanitizer = MoreObjects.firstNonNull(htmlSanitizer, HtmlSanitizer.DISABLED);
	return this;
	}

	public MarkdownToHtml build() {
	return new MarkdownToHtml(this);
	}
	}

	private HtmlBuilder html;
	private TocFormatter toc;
	private final String requestUri;
	private final GitilesView view;
	private final MarkdownConfig config;
	private final String filePath;
	private final HtmlSanitizer htmlSanitizer;
	private final ImageLoader imageLoader;
	private boolean outputNamedAnchor = true;

	protected MarkdownToHtml(Builder b) {
	requestUri = b.requestUri;
	view = b.view;
	config = b.config;
	filePath = b.filePath;
	htmlSanitizer = b.htmlSanitizer;
	imageLoader = newImageLoader(b);
	}

	protected HtmlBuilder html() {
	return html;
	}

	private static ImageLoader newImageLoader(Builder b) {
	if (b.reader != null && b.view != null && b.config != null && b.root != null) {
	return new ImageLoader(b.reader, b.view, b.config, b.root);
	}
	return null;
	}

	/** Render the document AST to sanitized HTML. */
	public void renderToHtml(HtmlBuilder out, Node node) {
	if (node != null) {
	html = out;
	toc = new TocFormatter(html, 3);
	toc.setRoot(node);
	node.accept(this);
	html.finish();
	html = null;
	toc = null;
	}
	}

	/** Render the document AST to sanitized HTML. */
	public SafeHtml toSoyHtml(Node node) {
	if (node != null) {
	SoyHtmlBuilder out = new SoyHtmlBuilder();
	renderToHtml(out, node);
	return out.toSoy();
	}
	return null;
	}

	@Override
	public void visit(Document node) {
	visitChildren(node);
	}

	private void visit(BlockNote node) {
	html.open("div").attribute("class", node.getClassName());
	Node f = node.getFirstChild();
	if (f == node.getLastChild() && f instanceof Paragraph) {
	// Avoid <p> inside <div> if there is only one <p>.
	visitChildren(f);
	} else {
	visitChildren(node);
	}
	html.close("div");
	}

	private void visit(MultiColumnBlock node) {
	html.open("div").attribute("class", "cols");
	visitChildren(node);
	html.close("div");
	}

	private void visit(MultiColumnBlock.Column node) {
	if (1 <= node.span && node.span <= MultiColumnBlock.GRID_WIDTH) {
	html.open("div").attribute("class", "col-" + node.span);
	visitChildren(node);
	html.close("div");
	}
	}

	private void visit(IframeBlock node) {
	if (HtmlBuilder.isValidHttpUri(node.src)
	&& HtmlBuilder.isValidCssDimension(node.height)
	&& HtmlBuilder.isValidCssDimension(node.width)
	&& config != null
	&& config.isIFrameAllowed(node.src)) {
	html.open("iframe")
	.attribute("src", node.src)
	.attribute("height", node.height)
	.attribute("width", node.width);
	if (!node.border) {
	html.attribute("class", "noborder");
	}
	html.close("iframe");
	}
	}

	@Override
	public void visit(Heading node) {
	outputNamedAnchor = false;
	String tag = "h" + node.getLevel();
	html.open(tag);
	String id = toc.idFromHeader(node);
	if (id != null) {
	html.open("a")
	.attribute("class", "h")
	.attribute("name", id)
	.attribute("href", "#" + id)
	.open("span")
	.close("span")
	.close("a");
	// github markdown compatibility
	if (!id.equals(id.toLowerCase())) {
	html.open("a")
	.attribute("class", "h")
	.attribute("name", id.toLowerCase())
	.attribute("href", "#" + id.toLowerCase())
	.open("span")
	.close("span")
	.close("a");
	}
	}
	visitChildren(node);
	html.close(tag);
	outputNamedAnchor = true;
	}

	private void visit(NamedAnchor node) {
	if (outputNamedAnchor) {
	html.open("a").attribute("name", node.getName()).close("a");
	}
	}

	@Override
	public void visit(Paragraph node) {
	if (isInTightList(node)) {
	// Avoid unnecessary <p> tags within <ol><li> structures.
	visitChildren(node);
	} else {
	wrapChildren("p", node);
	}
	}

	private static boolean isInTightList(Paragraph c) {
	Block b = c.getParent(); // b is probably a ListItem
	if (b != null) {
	Block a = b.getParent();
	return a instanceof ListBlock && ((ListBlock) a).isTight();
	}
	return false;
	}

	@Override
	public void visit(BlockQuote node) {
	wrapChildren("blockquote", node);
	}

	@Override
	public void visit(OrderedList node) {
	html.open("ol");
	if (node.getStartNumber() != 1) {
	html.attribute("start", Integer.toString(node.getStartNumber()));
	}
	visitChildren(node);
	html.close("ol");
	}

	@Override
	public void visit(BulletList node) {
	wrapChildren("ul", node);
	}

	@Override
	public void visit(ListItem node) {
	wrapChildren("li", node);
	}

	@Override
	public void visit(FencedCodeBlock node) {
	codeInPre(node.getInfo(), node.getLiteral());
	}

	@Override
	public void visit(IndentedCodeBlock node) {
	codeInPre(null, node.getLiteral());
	}

	private void codeInPre(String lang, String text) {
	html.open("pre").attribute("class", "code");
	text = printLeadingBlankLines(text);
	List<ParseResult> parsed = parse(lang, text);
	if (parsed != null) {
	int last = 0;
	for (ParseResult r : parsed) {
	span(null, text, last, r.getOffset());
	last = r.getOffset() + r.getLength();
	span(r.getStyleKeysString(), text, r.getOffset(), last);
	}
	if (last < text.length()) {
	span(null, text, last, text.length());
	}
	} else {
	html.appendAndEscape(text);
	}
	html.close("pre");
	}

	private String printLeadingBlankLines(String text) {
	int i = 0;
	while (i < text.length() && text.charAt(i) == '\n') {
	html.open("br");
	i++;
	}
	return text.substring(i);
	}

	private void span(String classes, String s, int start, int end) {
	if (end - start > 0) {
	if (Strings.isNullOrEmpty(classes)) {
	classes = Prettify.PR_PLAIN;
	}
	html.open("span").attribute("class", classes);
	html.appendAndEscape(s.substring(start, end));
	html.close("span");
	}
	}

	private List<ParseResult> parse(@Nullable String lang, String text) {
	if (Strings.isNullOrEmpty(lang)) {
	return null;
	}
	try {
	return ThreadSafePrettifyParser.INSTANCE.parse(lang, text);
	} catch (StackOverflowError e) {
	return null;
	}
	}

	@Override
	public void visit(Code node) {
	html.open("code").attribute("class", "code").appendAndEscape(node.getLiteral()).close("code");
	}

	@Override
	public void visit(Emphasis node) {
	wrapChildren("em", node);
	}

	@Override
	public void visit(StrongEmphasis node) {
	wrapChildren("strong", node);
	}

	@Override
	public void visit(Link node) {
	html.open("a")
	.attribute("href", href(node.getDestination()))
	.attribute("title", node.getTitle());
	visitChildren(node);
	html.close("a");
	}

	@VisibleForTesting
	String href(String target) {
	if (target.startsWith("#")
	\|\| HtmlBuilder.isValidHttpUri(target)
	\|\| HtmlBuilder.isValidMailtoUri(target)) {
	return target;
	} else if (target.startsWith("git:")) {
	if (HtmlBuilder.isValidGitUri(target)) {
	return target;
	}
	return SoyConstants.NORMAL_URI_INNOCUOUS_OUTPUT;
	}

	String anchor = "";
	int hash = target.indexOf('#');
	if (hash >= 0) {
	anchor = target.substring(hash);
	target = target.substring(0, hash);
	}

	String dest = PathResolver.resolve(filePath, target);
	if (dest == null \|\| view == null) {
	return SoyConstants.NORMAL_URI_INNOCUOUS_OUTPUT;
	}

	GitilesView.Builder b;
	if (view.getType() == GitilesView.Type.ROOTED_DOC) {
	b = GitilesView.rootedDoc();
	} else {
	b = GitilesView.path();
	}
	dest = b.copyFrom(view).setPathPart(dest).build().toUrl();

	return PathResolver.relative(requestUri, dest) + anchor;
	}

	@Override
	public void visit(Image node) {
	html.open("img")
	.attribute("src", image(node.getDestination()))
	.attribute("title", node.getTitle())
	.attribute("alt", getInnerText(node));
	}

	String image(String dest) {
	if (HtmlBuilder.isValidHttpUri(dest) \|\| HtmlBuilder.isImageDataUri(dest)) {
	return dest;
	} else if (imageLoader != null) {
	return imageLoader.inline(filePath, dest);
	}
	return SoyConstants.IMAGE_URI_INNOCUOUS_OUTPUT;
	}

	public void visit(TableBlock node) {
	wrapChildren("table", node);
	}

	private void visit(TableRow node) {
	wrapChildren("tr", node);
	}

	private void visit(TableCell cell) {
	String tag = cell.isHeader() ? "th" : "td";
	html.open(tag);
	TableCell.Alignment alignment = cell.getAlignment();
	if (alignment != null) {
	html.attribute("align", toHtml(alignment));
	}
	visitChildren(cell);
	html.close(tag);
	}

	private static String toHtml(TableCell.Alignment alignment) {
	switch (alignment) {
	case LEFT:
	return "left";
	case CENTER:
	return "center";
	case RIGHT:
	return "right";
	default:
	throw new IllegalArgumentException("unsupported alignment " + alignment);
	}
	}

	private void visit(SmartQuoted node) {
	switch (node.getType()) {
	case DOUBLE:
	html.entity("“");
	visitChildren(node);
	html.entity("”");
	break;
	case SINGLE:
	html.entity("‘");
	visitChildren(node);
	html.entity("’");
	break;
	default:
	throw new IllegalArgumentException("unsupported quote " + node.getType());
	}
	}

	@Override
	public void visit(Text node) {
	html.appendAndEscape(node.getLiteral());
	}

	@Override
	public void visit(SoftLineBreak node) {
	html.space();
	}

	@Override
	public void visit(HardLineBreak node) {
	html.open("br");
	}

	@Override
	public void visit(ThematicBreak thematicBreak) {
	html.open("hr");
	}

	@Override
	public void visit(HtmlInline node) {
	// Discard inline HTML, as it's always partial tags.
	}

	@Override
	public void visit(HtmlBlock node) {
	html.append(htmlSanitizer.sanitize(node.getLiteral()));
	}

	private void wrapChildren(String tag, Node node) {
	html.open(tag);
	visitChildren(node);
	html.close(tag);
	}

	private void visitChildren(Node node) {
	for (Node c = node.getFirstChild(); c != null; c = c.getNext()) {
	c.accept(this);
	}
	}

	@Override
	public void visit(CustomNode node) {
	if (node instanceof NamedAnchor) {
	visit((NamedAnchor) node);
	} else if (node instanceof SmartQuoted) {
	visit((SmartQuoted) node);
	} else if (node instanceof Strikethrough) {
	wrapChildren("del", node);
	} else if (node instanceof TableBody) {
	wrapChildren("tbody", node);
	} else if (node instanceof TableCell) {
	visit((TableCell) node);
	} else if (node instanceof TableHead) {
	wrapChildren("thead", node);
	} else if (node instanceof TableRow) {
	visit((TableRow) node);
	} else {
	throw new IllegalArgumentException("cannot render " + node.getClass());
	}
	}

	@Override
	public void visit(CustomBlock node) {
	if (node instanceof BlockNote) {
	visit((BlockNote) node);
	} else if (node instanceof IframeBlock) {
	visit((IframeBlock) node);
	} else if (node instanceof MultiColumnBlock) {
	visit((MultiColumnBlock) node);
	} else if (node instanceof MultiColumnBlock.Column) {
	visit((MultiColumnBlock.Column) node);
	} else if (node instanceof TableBlock) {
	visit((TableBlock) node);
	} else if (node instanceof TocBlock) {
	toc.format();
	} else {
	throw new IllegalArgumentException("cannot render " + node.getClass());
	}
	}
	}