wikitext/core/org.eclipse.mylyn.wikitext.markdown/src/main/java/org/eclipse/mylyn/wikitext/markdown/internal/MarkdownDocumentBuilder.java - mylyn/org.eclipse.mylyn.docs - Git at Google

 /*******************************************************************************
  * Copyright (c) 2014, 2015 Tasktop Technologies.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     Leo Dos Santos - initial API and implementation
  *******************************************************************************/

 package org.eclipse.mylyn.wikitext.markdown.internal;

 import static com.google.common.base.Preconditions.checkNotNull;

 import java.io.IOException;
 import java.io.StringWriter;
 import java.io.Writer;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.logging.Logger;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;

 import org.eclipse.mylyn.wikitext.markdown.MarkdownLanguage;
 import org.eclipse.mylyn.wikitext.parser.Attributes;
 import org.eclipse.mylyn.wikitext.parser.ImageAttributes;
 import org.eclipse.mylyn.wikitext.parser.LinkAttributes;
 import org.eclipse.mylyn.wikitext.parser.builder.AbstractMarkupDocumentBuilder;

 import com.google.common.base.CharMatcher;
 import com.google.common.base.Strings;

 /**
  * a document builder that emits Markdown markup
  *
  * @author Leo Dos Santos
  * @see MarkdownLanguage
  * @see MarkdownLanguage#createDocumentBuilder(Writer)
  */
 public class MarkdownDocumentBuilder extends AbstractMarkupDocumentBuilder {

 	private static final Pattern PATTERN_LINE_BREAK = Pattern.compile("(.*(\r\n|\r|\n)?)?"); //$NON-NLS-1$

 	private final Map<String, String> entityToLiteral = new HashMap<String, String>();
 	{
 		entityToLiteral.put("amp", "&"); //$NON-NLS-1$ //$NON-NLS-2$
 		entityToLiteral.put("lt", "<"); //$NON-NLS-1$ //$NON-NLS-2$
 		entityToLiteral.put("gt", ">"); //$NON-NLS-1$ //$NON-NLS-2$
 	}

 	private interface MarkdownBlock {

 		void lineBreak() throws IOException;

 	}

 	private class ContentBlock extends NewlineDelimitedBlock implements MarkdownBlock {

 		protected String prefix;

 		protected String suffix;

 		ContentBlock(BlockType blockType, String prefix, String suffix, int leadingNewlines, int trailingNewlines) {
 			super(blockType, leadingNewlines, trailingNewlines);
 			this.prefix = prefix;
 			this.suffix = suffix;
 		}

 		ContentBlock(String prefix, String suffix, int leadingNewlines, int trailingNewlines) {
 			this(null, prefix, suffix, leadingNewlines, trailingNewlines);
 		}

 		@Override
 		public void write(int c) throws IOException {
 			MarkdownDocumentBuilder.this.emitContent(c);
 		}

 		@Override
 		public void write(String s) throws IOException {
 			MarkdownDocumentBuilder.this.emitContent(s);
 		}

 		@Override
 		public void lineBreak() throws IOException {
 			write("  \n"); //$NON-NLS-1$
 		}

 		@Override
 		public void open() throws IOException {
 			super.open();
 			pushWriter(new StringWriter());
 		}

 		@Override
 		public void close() throws IOException {
 			Writer thisContent = popWriter();
 			String content = thisContent.toString();
 			if (content.length() > 0) {
 				emitContent(content);
 			}
 			super.close();
 		}

 		protected void emitContent(final String content) throws IOException {
 			MarkdownDocumentBuilder.this.emitContent(prefix);
 			MarkdownDocumentBuilder.this.emitContent(content);
 			MarkdownDocumentBuilder.this.emitContent(suffix);
 		}

 	}

 	private class ImplicitParagraphBlock extends ContentBlock {

 		ImplicitParagraphBlock() {
 			super(BlockType.PARAGRAPH, "", "", 2, 2); //$NON-NLS-1$ //$NON-NLS-2$
 		}

 		@Override
 		protected boolean isImplicitBlock() {
 			return true;
 		}

 	}

 	private class PrefixedLineContentBlock extends ContentBlock {

 		PrefixedLineContentBlock(BlockType blockType, String prefix, String suffix, int leadingNewlines,
 				int trailingNewlines) {
 			super(blockType, prefix, suffix, leadingNewlines, trailingNewlines);
 		}

 		@Override
 		protected void emitContent(String content) throws IOException {
 			// break out the block onto its own line if the last character
 			// was not a line break or null character literal
 			char lastChar = getLastChar();
 			if (lastChar != '\n' && lastChar != '\r' && lastChar != '\u0000') {
 				MarkdownDocumentBuilder.this.emitContent('\n');
 			}

 			// split out content by line break
 			Matcher matcher = PATTERN_LINE_BREAK.matcher(content);
 			while (matcher.find()) {
 				// if the line is empty, emit no prefix
 				String line = matcher.group(0);
 				if (!line.trim().isEmpty()) {
 					MarkdownDocumentBuilder.this.emitContent(prefix);
 				}
 				MarkdownDocumentBuilder.this.emitContent(line);
 			}
 			// collapse suffix for nested blocks
 			if (!content.endsWith(suffix)) {
 				MarkdownDocumentBuilder.this.emitContent(suffix);
 			}
 		}

 	}

 	private class ListBlock extends ContentBlock {

 		private int count = 0;

 		ListBlock(BlockType blockType, int leadingNewlines) {
 			super(blockType, "", "", leadingNewlines, 1); //$NON-NLS-1$//$NON-NLS-2$
 		}

 		@Override
 		protected void emitContent(String content) throws IOException {
 			MarkdownDocumentBuilder.this.emitContent(prefix);
 			MarkdownDocumentBuilder.this.emitContent(content);
 			if (!content.endsWith("\n\n")) { //$NON-NLS-1$
 				MarkdownDocumentBuilder.this.emitContent(suffix);
 			}
 		}

 		protected void addListItem(ListItemBlock item) {
 			checkNotNull(item);
 			count++;
 		}

 		protected int getCount() {
 			return count;
 		}

 	}

 	private class ListItemBlock extends ContentBlock {

 		private int count;

 		private ListItemBlock(String prefix) {
 			super(BlockType.LIST_ITEM, prefix, "", 1, 1); //$NON-NLS-1$
 		}

 		@Override
 		public void open() throws IOException {
 			super.open();
 			if (getPreviousBlock() instanceof ListBlock) {
 				ListBlock list = (ListBlock) getPreviousBlock();
 				list.addListItem(this);
 				count = list.getCount();
 			}
 		}

 		@Override
 		protected void emitContent(String content) throws IOException {
 			if (getPreviousBlock().getBlockType() == BlockType.NUMERIC_LIST) {
 				prefix = count + ". "; //$NON-NLS-1$
 			}
 			String indent = Strings.repeat(" ", prefix.length()); //$NON-NLS-1$

 			MarkdownDocumentBuilder.this.emitContent(prefix);
 			// split out content by line
 			Matcher matcher = PATTERN_LINE_BREAK.matcher(content);
 			int lines = 0;
 			while (matcher.find()) {
 				// indent each line hanging past the initial line item
 				String line = matcher.group(0);
 				if (lines > 0 && !line.trim().isEmpty()) {
 					int indexOfFirstNonSpace = CharMatcher.isNot(' ').indexIn(line);
 					if (indexOfFirstNonSpace >= 4) {
 						line = Strings.repeat(" ", 4) + line; //$NON-NLS-1$
 					} else {
 						line = indent + line;
 					}
 				}
 				MarkdownDocumentBuilder.this.emitContent(line);
 				lines++;
 			}
 			// collapse suffix for nested blocks
 			if (!content.endsWith(suffix)) {
 				MarkdownDocumentBuilder.this.emitContent(suffix);
 			}
 		}

 	}

 	private class LinkBlock extends ContentBlock {

 		private final LinkAttributes attributes;

 		LinkBlock(LinkAttributes attributes) {
 			super("", "", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
 			this.attributes = attributes;
 		}

 		@Override
 		protected void emitContent(String content) throws IOException {
 			// [label](http://url.com) or
 			// [label](http://url.com "title")
 			MarkdownDocumentBuilder.this.emitContent('[');
 			MarkdownDocumentBuilder.this.emitContent(content);
 			MarkdownDocumentBuilder.this.emitContent(']');

 			MarkdownDocumentBuilder.this.emitContent('(');
 			MarkdownDocumentBuilder.this.emitContent(attributes.getHref());
 			if (!Strings.isNullOrEmpty(attributes.getTitle())) {
 				MarkdownDocumentBuilder.this.emitContent(" \""); //$NON-NLS-1$
 				MarkdownDocumentBuilder.this.emitContent(attributes.getTitle());
 				MarkdownDocumentBuilder.this.emitContent('"');
 			}
 			MarkdownDocumentBuilder.this.emitContent(')');
 		}

 	}

 	private class CodeSpan extends ContentBlock {

 		private CodeSpan() {
 			super("`", "`", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
 		}

 		@Override
 		protected void emitContent(String content) throws IOException {
 			if (content.contains("`")) { //$NON-NLS-1$
 				prefix = "`` "; //$NON-NLS-1$
 				suffix = " ``"; //$NON-NLS-1$
 			}
 			super.emitContent(content);
 		}

 	}

 	public MarkdownDocumentBuilder(Writer out) {
 		super(out);
 		currentBlock = null;
 	}

 	@Override
 	protected Block computeBlock(BlockType type, Attributes attributes) {
 		switch (type) {
 		case PARAGRAPH:
 			return new ContentBlock(type, "", "", 2, 2); //$NON-NLS-1$ //$NON-NLS-2$
 		case QUOTE:
 			return new PrefixedLineContentBlock(type, "> ", "", 1, 1); //$NON-NLS-1$ //$NON-NLS-2$
 		case BULLETED_LIST:
 		case NUMERIC_LIST:
 			if (currentBlock != null) {
 				BlockType currentBlockType = currentBlock.getBlockType();
 				if (currentBlockType == BlockType.LIST_ITEM || currentBlockType == BlockType.DEFINITION_ITEM
 						|| currentBlockType == BlockType.DEFINITION_TERM) {
 					return new ListBlock(type, 1);
 				}
 			}
 			return new ListBlock(type, 2);
 		case LIST_ITEM:
 			if (computeCurrentListType() == BlockType.NUMERIC_LIST) {
 				return new ListItemBlock("1. "); //$NON-NLS-1$
 			}
 			return new ListItemBlock("* "); //$NON-NLS-1$
 		case CODE:
 			return new PrefixedLineContentBlock(type, "    ", "", 1, 2); //$NON-NLS-1$ //$NON-NLS-2$
 		default:
 			Logger.getLogger(getClass().getName()).warning("Unexpected block type: " + type); //$NON-NLS-1$
 			return new ContentBlock(type, "", "", 2, 2); //$NON-NLS-1$ //$NON-NLS-2$
 		}
 	}

 	@Override
 	protected Block computeSpan(SpanType type, Attributes attributes) {
 		switch (type) {
 		case LINK:
 			if (attributes instanceof LinkAttributes) {
 				return new LinkBlock((LinkAttributes) attributes);
 			}
 			return new ContentBlock("<", ">", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
 		case ITALIC:
 		case EMPHASIS:
 		case MARK:
 			return new ContentBlock("*", "*", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
 		case BOLD:
 		case STRONG:
 			return new ContentBlock("**", "**", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
 		case CODE:
 			return new CodeSpan();
 		default:
 			Logger.getLogger(getClass().getName()).warning("Unexpected block type: " + type); //$NON-NLS-1$
 			return new ContentBlock("", "", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
 		}
 	}

 	@Override
 	protected Block computeHeading(int level, Attributes attributes) {
 		return new ContentBlock(computePrefix('#', level) + " ", "", 1, 2); //$NON-NLS-1$ //$NON-NLS-2$
 	}

 	@Override
 	public void characters(String text) {
 		text = escapeAmpersand(text);
 		assertOpenBlock();
 		try {
 			currentBlock.write(text);
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
 	}

 	private String escapeAmpersand(String text) {
 		return text.replace("&", "&amp;"); //$NON-NLS-1$ //$NON-NLS-2$
 	}

 	@Override
 	public void entityReference(String entity) {
 		assertOpenBlock();
 		String literal = entityToLiteral.get(entity);
 		if (literal == null) {
 			literal = "&" + entity + ";"; //$NON-NLS-1$//$NON-NLS-2$
 		}
 		try {
 			currentBlock.write(literal);
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
 	}

 	@Override
 	public void image(Attributes attributes, String url) {
 		assertOpenBlock();
 		try {
 			currentBlock.write(computeImage(attributes, url));
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
 	}

 	private String computeImage(Attributes attributes, String url) {
 		// ![](/path/to/img.jpg) or
 		// ![alt text](path/to/img.jpg "title")
 		String altText = ""; //$NON-NLS-1$
 		String title = ""; //$NON-NLS-1$
 		if (attributes instanceof ImageAttributes) {
 			ImageAttributes imageAttr = (ImageAttributes) attributes;
 			altText = Strings.nullToEmpty(imageAttr.getAlt());
 		}
 		if (!Strings.isNullOrEmpty(attributes.getTitle())) {
 			title = " \"" + attributes.getTitle() + '"'; //$NON-NLS-1$
 		}
 		return "![" + altText + "](" + Strings.nullToEmpty(url) + title + ')'; //$NON-NLS-1$ //$NON-NLS-2$
 	}

 	@Override
 	public void link(Attributes attributes, String hrefOrHashName, String text) {
 		assertOpenBlock();
 		LinkAttributes linkAttr = new LinkAttributes();
 		linkAttr.setTitle(attributes.getTitle());
 		linkAttr.setHref(hrefOrHashName);
 		beginSpan(SpanType.LINK, linkAttr);
 		characters(text);
 		endSpan();
 	}

 	@Override
 	public void imageLink(Attributes linkAttributes, Attributes imageAttributes, String href, String imageUrl) {
 		link(linkAttributes, href, computeImage(imageAttributes, imageUrl));
 	}

 	@Override
 	public void acronym(String text, String definition) {
 		throw new UnsupportedOperationException();
 	}

 	@Override
 	public void lineBreak() {
 		assertOpenBlock();
 		try {
 			if (currentBlock instanceof MarkdownBlock) {
 				((MarkdownBlock) currentBlock).lineBreak();
 			}
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
 	}

 	@Override
 	protected Block createImplicitParagraphBlock() {
 		return new ImplicitParagraphBlock();
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2014, 2015 Tasktop Technologies.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* Leo Dos Santos - initial API and implementation
	*******************************************************************************/

	package org.eclipse.mylyn.wikitext.markdown.internal;

	import static com.google.common.base.Preconditions.checkNotNull;

	import java.io.IOException;
	import java.io.StringWriter;
	import java.io.Writer;
	import java.util.HashMap;
	import java.util.Map;
	import java.util.logging.Logger;
	import java.util.regex.Matcher;
	import java.util.regex.Pattern;

	import org.eclipse.mylyn.wikitext.markdown.MarkdownLanguage;
	import org.eclipse.mylyn.wikitext.parser.Attributes;
	import org.eclipse.mylyn.wikitext.parser.ImageAttributes;
	import org.eclipse.mylyn.wikitext.parser.LinkAttributes;
	import org.eclipse.mylyn.wikitext.parser.builder.AbstractMarkupDocumentBuilder;

	import com.google.common.base.CharMatcher;
	import com.google.common.base.Strings;

	/**
	* a document builder that emits Markdown markup
	*
	* @author Leo Dos Santos
	* @see MarkdownLanguage
	* @see MarkdownLanguage#createDocumentBuilder(Writer)
	*/
	public class MarkdownDocumentBuilder extends AbstractMarkupDocumentBuilder {

	private static final Pattern PATTERN_LINE_BREAK = Pattern.compile("(.*(\r\n\|\r\|\n)?)?"); //$NON-NLS-1$

	private final Map<String, String> entityToLiteral = new HashMap<String, String>();
	{
	entityToLiteral.put("amp", "&"); //$NON-NLS-1$ //$NON-NLS-2$
	entityToLiteral.put("lt", "<"); //$NON-NLS-1$ //$NON-NLS-2$
	entityToLiteral.put("gt", ">"); //$NON-NLS-1$ //$NON-NLS-2$
	}

	private interface MarkdownBlock {

	void lineBreak() throws IOException;

	}

	private class ContentBlock extends NewlineDelimitedBlock implements MarkdownBlock {

	protected String prefix;

	protected String suffix;

	ContentBlock(BlockType blockType, String prefix, String suffix, int leadingNewlines, int trailingNewlines) {
	super(blockType, leadingNewlines, trailingNewlines);
	this.prefix = prefix;
	this.suffix = suffix;
	}

	ContentBlock(String prefix, String suffix, int leadingNewlines, int trailingNewlines) {
	this(null, prefix, suffix, leadingNewlines, trailingNewlines);
	}

	@Override
	public void write(int c) throws IOException {
	MarkdownDocumentBuilder.this.emitContent(c);
	}

	@Override
	public void write(String s) throws IOException {
	MarkdownDocumentBuilder.this.emitContent(s);
	}

	@Override
	public void lineBreak() throws IOException {
	write(" \n"); //$NON-NLS-1$
	}

	@Override
	public void open() throws IOException {
	super.open();
	pushWriter(new StringWriter());
	}

	@Override
	public void close() throws IOException {
	Writer thisContent = popWriter();
	String content = thisContent.toString();
	if (content.length() > 0) {
	emitContent(content);
	}
	super.close();
	}

	protected void emitContent(final String content) throws IOException {
	MarkdownDocumentBuilder.this.emitContent(prefix);
	MarkdownDocumentBuilder.this.emitContent(content);
	MarkdownDocumentBuilder.this.emitContent(suffix);
	}

	}

	private class ImplicitParagraphBlock extends ContentBlock {

	ImplicitParagraphBlock() {
	super(BlockType.PARAGRAPH, "", "", 2, 2); //$NON-NLS-1$ //$NON-NLS-2$
	}

	@Override
	protected boolean isImplicitBlock() {
	return true;
	}

	}

	private class PrefixedLineContentBlock extends ContentBlock {

	PrefixedLineContentBlock(BlockType blockType, String prefix, String suffix, int leadingNewlines,
	int trailingNewlines) {
	super(blockType, prefix, suffix, leadingNewlines, trailingNewlines);
	}

	@Override
	protected void emitContent(String content) throws IOException {
	// break out the block onto its own line if the last character
	// was not a line break or null character literal
	char lastChar = getLastChar();
	if (lastChar != '\n' && lastChar != '\r' && lastChar != '\u0000') {
	MarkdownDocumentBuilder.this.emitContent('\n');
	}

	// split out content by line break
	Matcher matcher = PATTERN_LINE_BREAK.matcher(content);
	while (matcher.find()) {
	// if the line is empty, emit no prefix
	String line = matcher.group(0);
	if (!line.trim().isEmpty()) {
	MarkdownDocumentBuilder.this.emitContent(prefix);
	}
	MarkdownDocumentBuilder.this.emitContent(line);
	}
	// collapse suffix for nested blocks
	if (!content.endsWith(suffix)) {
	MarkdownDocumentBuilder.this.emitContent(suffix);
	}
	}

	}

	private class ListBlock extends ContentBlock {

	private int count = 0;

	ListBlock(BlockType blockType, int leadingNewlines) {
	super(blockType, "", "", leadingNewlines, 1); //$NON-NLS-1$//$NON-NLS-2$
	}

	@Override
	protected void emitContent(String content) throws IOException {
	MarkdownDocumentBuilder.this.emitContent(prefix);
	MarkdownDocumentBuilder.this.emitContent(content);
	if (!content.endsWith("\n\n")) { //$NON-NLS-1$
	MarkdownDocumentBuilder.this.emitContent(suffix);
	}
	}

	protected void addListItem(ListItemBlock item) {
	checkNotNull(item);
	count++;
	}

	protected int getCount() {
	return count;
	}

	}

	private class ListItemBlock extends ContentBlock {

	private int count;

	private ListItemBlock(String prefix) {
	super(BlockType.LIST_ITEM, prefix, "", 1, 1); //$NON-NLS-1$
	}

	@Override
	public void open() throws IOException {
	super.open();
	if (getPreviousBlock() instanceof ListBlock) {
	ListBlock list = (ListBlock) getPreviousBlock();
	list.addListItem(this);
	count = list.getCount();
	}
	}

	@Override
	protected void emitContent(String content) throws IOException {
	if (getPreviousBlock().getBlockType() == BlockType.NUMERIC_LIST) {
	prefix = count + ". "; //$NON-NLS-1$
	}
	String indent = Strings.repeat(" ", prefix.length()); //$NON-NLS-1$

	MarkdownDocumentBuilder.this.emitContent(prefix);
	// split out content by line
	Matcher matcher = PATTERN_LINE_BREAK.matcher(content);
	int lines = 0;
	while (matcher.find()) {
	// indent each line hanging past the initial line item
	String line = matcher.group(0);
	if (lines > 0 && !line.trim().isEmpty()) {
	int indexOfFirstNonSpace = CharMatcher.isNot(' ').indexIn(line);
	if (indexOfFirstNonSpace >= 4) {
	line = Strings.repeat(" ", 4) + line; //$NON-NLS-1$
	} else {
	line = indent + line;
	}
	}
	MarkdownDocumentBuilder.this.emitContent(line);
	lines++;
	}
	// collapse suffix for nested blocks
	if (!content.endsWith(suffix)) {
	MarkdownDocumentBuilder.this.emitContent(suffix);
	}
	}

	}

	private class LinkBlock extends ContentBlock {

	private final LinkAttributes attributes;

	LinkBlock(LinkAttributes attributes) {
	super("", "", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
	this.attributes = attributes;
	}

	@Override
	protected void emitContent(String content) throws IOException {
	// [label](http://url.com) or
	// [label](http://url.com "title")
	MarkdownDocumentBuilder.this.emitContent('[');
	MarkdownDocumentBuilder.this.emitContent(content);
	MarkdownDocumentBuilder.this.emitContent(']');

	MarkdownDocumentBuilder.this.emitContent('(');
	MarkdownDocumentBuilder.this.emitContent(attributes.getHref());
	if (!Strings.isNullOrEmpty(attributes.getTitle())) {
	MarkdownDocumentBuilder.this.emitContent(" \""); //$NON-NLS-1$
	MarkdownDocumentBuilder.this.emitContent(attributes.getTitle());
	MarkdownDocumentBuilder.this.emitContent('"');
	}
	MarkdownDocumentBuilder.this.emitContent(')');
	}

	}

	private class CodeSpan extends ContentBlock {

	private CodeSpan() {
	super("`", "`", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
	}

	@Override
	protected void emitContent(String content) throws IOException {
	if (content.contains("`")) { //$NON-NLS-1$
	prefix = "`` "; //$NON-NLS-1$
	suffix = " ``"; //$NON-NLS-1$
	}
	super.emitContent(content);
	}

	}

	public MarkdownDocumentBuilder(Writer out) {
	super(out);
	currentBlock = null;
	}

	@Override
	protected Block computeBlock(BlockType type, Attributes attributes) {
	switch (type) {
	case PARAGRAPH:
	return new ContentBlock(type, "", "", 2, 2); //$NON-NLS-1$ //$NON-NLS-2$
	case QUOTE:
	return new PrefixedLineContentBlock(type, "> ", "", 1, 1); //$NON-NLS-1$ //$NON-NLS-2$
	case BULLETED_LIST:
	case NUMERIC_LIST:
	if (currentBlock != null) {
	BlockType currentBlockType = currentBlock.getBlockType();
	if (currentBlockType == BlockType.LIST_ITEM \|\| currentBlockType == BlockType.DEFINITION_ITEM
	\|\| currentBlockType == BlockType.DEFINITION_TERM) {
	return new ListBlock(type, 1);
	}
	}
	return new ListBlock(type, 2);
	case LIST_ITEM:
	if (computeCurrentListType() == BlockType.NUMERIC_LIST) {
	return new ListItemBlock("1. "); //$NON-NLS-1$
	}
	return new ListItemBlock("* "); //$NON-NLS-1$
	case CODE:
	return new PrefixedLineContentBlock(type, " ", "", 1, 2); //$NON-NLS-1$ //$NON-NLS-2$
	default:
	Logger.getLogger(getClass().getName()).warning("Unexpected block type: " + type); //$NON-NLS-1$
	return new ContentBlock(type, "", "", 2, 2); //$NON-NLS-1$ //$NON-NLS-2$
	}
	}

	@Override
	protected Block computeSpan(SpanType type, Attributes attributes) {
	switch (type) {
	case LINK:
	if (attributes instanceof LinkAttributes) {
	return new LinkBlock((LinkAttributes) attributes);
	}
	return new ContentBlock("<", ">", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
	case ITALIC:
	case EMPHASIS:
	case MARK:
	return new ContentBlock("", "", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
	case BOLD:
	case STRONG:
	return new ContentBlock("", "", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
	case CODE:
	return new CodeSpan();
	default:
	Logger.getLogger(getClass().getName()).warning("Unexpected block type: " + type); //$NON-NLS-1$
	return new ContentBlock("", "", 0, 0); //$NON-NLS-1$ //$NON-NLS-2$
	}
	}

	@Override
	protected Block computeHeading(int level, Attributes attributes) {
	return new ContentBlock(computePrefix('#', level) + " ", "", 1, 2); //$NON-NLS-1$ //$NON-NLS-2$
	}

	@Override
	public void characters(String text) {
	text = escapeAmpersand(text);
	assertOpenBlock();
	try {
	currentBlock.write(text);
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	}

	private String escapeAmpersand(String text) {
	return text.replace("&", "&"); //$NON-NLS-1$ //$NON-NLS-2$
	}

	@Override
	public void entityReference(String entity) {
	assertOpenBlock();
	String literal = entityToLiteral.get(entity);
	if (literal == null) {
	literal = "&" + entity + ";"; //$NON-NLS-1$//$NON-NLS-2$
	}
	try {
	currentBlock.write(literal);
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public void image(Attributes attributes, String url) {
	assertOpenBlock();
	try {
	currentBlock.write(computeImage(attributes, url));
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	}

	private String computeImage(Attributes attributes, String url) {
	// ![](/path/to/img.jpg) or
	// ![alt text](path/to/img.jpg "title")
	String altText = ""; //$NON-NLS-1$
	String title = ""; //$NON-NLS-1$
	if (attributes instanceof ImageAttributes) {
	ImageAttributes imageAttr = (ImageAttributes) attributes;
	altText = Strings.nullToEmpty(imageAttr.getAlt());
	}
	if (!Strings.isNullOrEmpty(attributes.getTitle())) {
	title = " \"" + attributes.getTitle() + '"'; //$NON-NLS-1$
	}
	return "![" + altText + "](" + Strings.nullToEmpty(url) + title + ')'; //$NON-NLS-1$ //$NON-NLS-2$
	}

	@Override
	public void link(Attributes attributes, String hrefOrHashName, String text) {
	assertOpenBlock();
	LinkAttributes linkAttr = new LinkAttributes();
	linkAttr.setTitle(attributes.getTitle());
	linkAttr.setHref(hrefOrHashName);
	beginSpan(SpanType.LINK, linkAttr);
	characters(text);
	endSpan();
	}

	@Override
	public void imageLink(Attributes linkAttributes, Attributes imageAttributes, String href, String imageUrl) {
	link(linkAttributes, href, computeImage(imageAttributes, imageUrl));
	}

	@Override
	public void acronym(String text, String definition) {
	throw new UnsupportedOperationException();
	}

	@Override
	public void lineBreak() {
	assertOpenBlock();
	try {
	if (currentBlock instanceof MarkdownBlock) {
	((MarkdownBlock) currentBlock).lineBreak();
	}
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	protected Block createImplicitParagraphBlock() {
	return new ImplicitParagraphBlock();
	}

	}