HTMLUtils.java

/*
 * Copyright 2011 cruxframework.org.
 * 
 * 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 org.cruxframework.crux.core.utils;

import java.io.IOException;
import java.io.Writer;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

import org.cruxframework.crux.core.rebind.screen.widget.ViewFactoryCreator;
import org.w3c.dom.CDATASection;
import org.w3c.dom.DOMException;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * 
 * Helper class for HTML generation, according with {@link http://dev.w3.org/html5/spec/syntax.html#elements-0}
 * @author Thiago da Rosa de Bustamante
 *
 */
public class HTMLUtils
{
	private static Set<String> rawTextElements = new HashSet<String>();
	private static Set<String> rcDataElements = new HashSet<String>();
	private static Set<String> voidElements = new HashSet<String>();

	static
	{
		voidElements.addAll(Arrays.asList(new String[]{
				"area", "base", "br", "col", "command", "embed", "hr", "img", "input", "keygen", "link", "meta", "param", "source", "track", "wbr"
		}));
		
		rawTextElements.addAll(Arrays.asList(new String[]{"style", "script"}));
		rcDataElements.addAll(Arrays.asList(new String[]{"textarea", "title"}));
	}
	
	
	/**
	 * @param document
	 */
	private HTMLUtils()
    {
    }

	/**
	 * @param s
	 * @return
	 */
	public static String escapeHTML(String s)
	{
		return escapeHTML(s, true);
	}

	/**
	 * @param s
	 * @return
	 */
	public static String escapeHTMLAttribute(String s)
	{
		return escapeHTML(s, false);
	}
	
	/**
	 * @param s
	 * @return
	 */
	public static String escapeJavascriptString(String s, boolean escapeXML)
	{
		StringBuilder sb = new StringBuilder();
		int n = s.length();
		
		for (int i = 0; i < n; i++)
		{
			char c = s.charAt(i);
			switch (c)
			{
				case '\\': sb.append("\\\\"); break;
				case '"': sb.append("\\\""); break;
				case '\n': sb.append("\\n"); break;
				case '\r': sb.append("\\r"); break;
				case '\t': sb.append("\\t"); break;
				case '<': 
					if (escapeXML) sb.append("<");
					else sb.append("<");
				break;
				case '>': 
					if (escapeXML) sb.append(">"); 
					else sb.append(">");
				break;
	
				default: sb.append(c); break;
			}
		}
		s = sb.toString().replace(""", "\\\"");
		return s;
	}
	
	/**
	 * @param viewId
	 * @param device
	 * @param nativeControllers
	 * @param nativeBindings 
	 * @param node
	 * @param out
	 * @throws IOException
	 */
	public static void write(String viewId, String device, StringBuilder nativeControllers, 
							StringBuilder nativeBindings, Node node, Writer out) throws IOException
	{
		write(viewId, device, nativeControllers, nativeBindings, node, out, false);
	}
	
	/**
	 * @param viewId
	 * @param device
	 * @param nativeControllers 
	 * @param nativeBindings 
	 * @param node
	 * @param out
	 * @param indentOutput
	 * @throws IOException
	 */
	public static void write(String viewId, String device, StringBuilder nativeControllers, StringBuilder nativeBindings, 
							Node node, Writer out, boolean indentOutput) throws IOException
	{
		if (node.getNodeType() == Node.ELEMENT_NODE)
		{
			String name = ((Element)node).getNodeName().toLowerCase();
			out.write("<");
			out.write(name);
			writeAttributes(viewId, device, nativeControllers, nativeBindings, node, out);
			
			if (voidElements.contains(name))
			{
				out.write("/>");
			}
			else
			{
				out.write(">");

				NodeList children = node.getChildNodes();
				if (children != null)
				{
					for (int i=0; i< children.getLength(); i++)
					{
						Node child = children.item(i);
						if (rawTextElements.contains(name))
						{
							writeRawText(child, out);
						}
						else if (rcDataElements.contains(name))
						{
							writeRcData(child, out);
						}
						else
						{
							write(viewId, device, nativeControllers, nativeBindings, child, out, indentOutput);
						}
					}
				}
				out.write("</");
				out.write(name);
				out.write(">");
			}
		}
		else if (node.getNodeType() == Node.TEXT_NODE)
		{
			if (indentOutput)
			{
				out.write(escapeIndentedHTML(node.getNodeValue()));
			}
			else
			{
				out.write(escapeHTML(node.getNodeValue()));
			}
		}
	}

	/**
	 * @param viewId
	 * @param device
	 * @param nativeControllers 
	 * @param nativeBindings
	 * @param node
	 * @param out
	 * @throws IOException
	 */
	public static void writeAttributes(String viewId, String device, StringBuilder nativeControllers,
										StringBuilder nativeBindings, Node node, Writer out) throws IOException
    {
	    NamedNodeMap attributes = node.getAttributes();
	    Node idAttr = node.getAttributes().getNamedItem("id");
	    String id = null;
	    if (idAttr != null)
	    {
	    	id = idAttr.getNodeValue();
	    }
	    for (int i=0; i<attributes.getLength(); i++)
	    {
	    	Node attribute = attributes.item(i);
	    	String name = attribute.getNodeName();
	    	String nameLowerCase = name.toLowerCase();
			if (!nameLowerCase.startsWith("xmlns"))
	    	{
	    		String attributeValue = attribute.getNodeValue();
	    		if (!writeAttributeWithController(viewId, device, nativeControllers, out, name, nameLowerCase, attributeValue))
	    		{
	    			AttributeDataBindingStatus status = processAttributeDataBinding(viewId, device, nativeBindings, out, name, nameLowerCase, attributeValue, id);
	    			if (!status.status)
	    			{
	    				out.write(" "+name+"=\""+escapeHTMLAttribute(attributeValue)+"\"");
	    			}
	    			else
	    			{
	    				id = status.id;
	    			}
	    		}
	    	}
	    }
    }
	
	
	/**
	 * @param child
	 * @param out
	 * @throws IOException 
	 * @throws DOMException 
	 */
	public static void writeRawText(Node child, Writer out) throws DOMException, IOException
    {
		
		boolean isCDATA = child instanceof CDATASection;
		if (isCDATA)
		{
			out.write("<![CDATA[");
		}
		out.write(child.getNodeValue()); 
		if (isCDATA)
		{
			out.write("]]>");
		}
    }
	
	/**
	 * @param child
	 * @param out
	 * @throws DOMException
	 * @throws IOException
	 */
	public static void writeRcData(Node child, Writer out) throws DOMException, IOException
    {
	    out.write(child.getNodeValue()); 
    }

	/**
	 * @param s
	 * @return
	 */
	private static String escapeHTML(String s, boolean normalizeSpaces)
	{
		StringBuilder sb = new StringBuilder();
		s = s.replaceAll("
", " ");
		s = s.replaceAll("
", " ");
		int n = s.length();
		boolean lastIsSpace = false;
		
		for (int i = 0; i < n; i++)
		{
			char c = s.charAt(i);
			if (c != ' ' && c != '\n' && c != '\r' && c != '\t')
			{
				lastIsSpace = false;
			}
			switch (c)
			{
				case '\n': 
				case '\r': 
				case '\t': 
				case ' ':
					if (normalizeSpaces)
					{
						if (!lastIsSpace)
						{
							sb.append(" ");
							lastIsSpace = true;
						}
					}
					else
					{
						sb.append(" ");
					}
				break;
				case '&': sb.append("&"); break;
				case '"': sb.append("""); break;
				case '\'': sb.append("'"); break;
				case '<': sb.append("<"); break;
				case '>': sb.append(">"); break;
	
				default: sb.append(c); break;
			}
		}
		return (sb.toString());
	}
	
	/**
	 * @param s
	 * @return
	 */
	private static String escapeIndentedHTML(String s)
	{
		StringBuilder sb = new StringBuilder();
		int n = s.length();
		
		for (int i = 0; i < n; i++)
		{
			char c = s.charAt(i);
			switch (c)
			{
				case '&': sb.append("&"); break;
				case '"': sb.append("""); break;
				case '\'': sb.append("'"); break;
				case '<': sb.append("<"); break;
				case '>': sb.append(">"); break;
	
				default: sb.append(c); break;
			}
		}
		return (sb.toString());
	}

	private static boolean writeAttributeWithController(String viewId, String device, StringBuilder nativeControllers, Writer out,
												String attributeName, String attributeNameLower, String attributeValue) throws IOException
	{
		if (nativeControllers != null && attributeNameLower.startsWith("on") 
			&& RegexpPatterns.REGEXP_CRUX_CONTROLLER_CALL.matcher(attributeValue.trim()).matches())
		{
			String controllerCall = attributeValue.trim();
			String controllerNativeCall = controllerCall.substring(1, controllerCall.length()-1);
			String methodCall = viewId.replaceAll("\\W", "_") + "_" + device + "_" + controllerNativeCall.replace('.', '_');
			out.write(" "+attributeName+"=\""+methodCall+"(event)"+"\"");
			
			if (nativeControllers.length() > 1)
			{
				nativeControllers.append(",");
			}
			nativeControllers.append("{\"method\": \""+methodCall+"\"," 
								   + "\"controllerCall\" : \""+controllerCall+"\"}");
			return true;
		}
		return false;
	}

	private static AttributeDataBindingStatus processAttributeDataBinding(String viewId, String device, StringBuilder nativeBindings, Writer out,
		String attributeName, String attributeNameLower, String attributeValue, String id) throws IOException
	{
		if (!attributeNameLower.startsWith("on") 
			&& RegexpPatterns.REGEXP_CRUX_OBJECT_DATA_BINDING.matcher(attributeValue.trim()).find())
		{
			String dataBinding = attributeValue.trim();
			if (id == null)
			{
				id = ViewFactoryCreator.createVariableName(viewId.replaceAll("\\W", "_") + "_" + device + "_elem");
				out.write(" id=\""+escapeHTMLAttribute(id)+"\"");
			}

			if (nativeBindings != null)
			{
				if (nativeBindings.length() > 1)
				{
					nativeBindings.append(",");
				}
				nativeBindings.append("{\"elementId\": \""+id+"\"," 
					+ "\"dataBinding\" : \""+dataBinding+"\","
					+ "\"attributeName\" : \""+attributeName+"\"}");
			}
			return new AttributeDataBindingStatus(id, true);
		}
		return new AttributeDataBindingStatus(id, false);
	}
	
	private static class AttributeDataBindingStatus
	{
		private AttributeDataBindingStatus(String id, boolean status)
        {
			this.id = id;
			this.status = status;
        }
		private boolean status;
		private String id;
	}
	
}