zweb/src/main/java/org/zkoss/web/servlet/dsp/impl/Parser.java
/* Parser.java
Purpose:
Description:
History:
Sat Sep 17 12:12:41 2005, Created by tomyeh
Copyright (C) 2004 Potix Corporation. All Rights Reserved.
{{IS_RIGHT
This program is distributed under LGPL Version 2.1 in the hope that
it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.web.servlet.dsp.impl;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URL;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.zkoss.idom.Element;
import org.zkoss.idom.input.SAXBuilder;
import org.zkoss.idom.util.IDOMs;
import org.zkoss.lang.Classes;
import org.zkoss.util.resource.Locator;
import org.zkoss.web.mesg.MWeb;
import org.zkoss.web.servlet.dsp.DspException;
import org.zkoss.web.servlet.dsp.Interpretation;
import org.zkoss.web.servlet.dsp.action.Action;
import org.zkoss.web.servlet.dsp.action.Page;
import org.zkoss.xel.ExpressionFactory;
import org.zkoss.xel.Expressions;
import org.zkoss.xel.FunctionMapper;
import org.zkoss.xel.VariableResolver;
import org.zkoss.xel.XelContext;
import org.zkoss.xel.XelException;
import org.zkoss.xel.taglib.Taglibs;
import org.zkoss.xel.util.SimpleMapper;
/**
* Used to parse a DSP page into a meta format called
* {@link Interpretation}.
*
* @author tomyeh
*/
public class Parser {
/** Parses the content into a meta format
*
* @param content the content to parse; never null.
* @param ctype the content type. Optional. It is used only if
* no page action at all. If it is not specified and not page
* action, "text/html" is assumed.
* @param xelc the context information used to parse XEL expressions
* in the content.
* @param loc used to locate the resource such as taglib.
* It could null only if DSP contains no such resource.
*/
public Interpretation parse(String content, String ctype, XelContext xelc, Locator loc)
throws DspException, IOException, XelException {
final Context ctx = new Context(content, xelc, loc);
final RootNode root = new RootNode();
parse0(ctx, root, 0, content.length());
root.setFunctionMapper(ctx.getFunctionMapper());
if (!ctx.pageDefined) {
//We always create a page definition
final ActionNode action = new ActionNode(Page.class, 0);
root.addChild(0, action);
final Map<String, String> attrs = new HashMap<String, String>(2);
if (ctype == null)
ctype = "text/html";
else if (ctype.length() > 0 && ctype.charAt(0) == ';')
ctype = "text/html" + ctype;
attrs.put("optionalContentType", ctype);
applyAttrs("page", action, attrs, ctx);
}
return root;
}
/** Recursively parse the content into a tree of {@link Node}.
*/
private static void parse0(Context ctx, Node parent, int from, int to)
throws DspException, IOException, XelException {
boolean esc = false;
final StringBuffer sb = new StringBuffer(512);
for (int j = from; j < to; ++j) {
char cc = ctx.content.charAt(j);
//We only recognize <%, <\%, ${, $\{ and <xx:yy>
switch (cc) {
case '<':
if (j + 1 < to) {
char c2 = ctx.content.charAt(j + 1);
if (c2 == '\\') {
if (j + 2 < to && ctx.content.charAt(j + 2) == '%')
++j; //skip '\\'
} else if (c2 == '%') {
addText(parent, sb);
j = parseControl(ctx, parent, j, to);
continue;
} else {
final int oldLines = ctx.nLines;
int k = skipWhitespaces(ctx, j + 1, to);
int l = nextSeparator(ctx, k, to);
if (l >= to || l == k || ctx.content.charAt(l) != ':') {
ctx.nLines = oldLines;
break; //bypass what we don't recognize
}
final String prefix = ctx.content.substring(k, l);
if (!ctx.hasPrefix(prefix)) {
ctx.nLines = oldLines;
break; //bypass what we don't recognize
}
addText(parent, sb);
j = parseAction(ctx, parent, prefix, l, to);
continue;
}
}
break;
case '$':
if (j + 1 < to) {
char c2 = ctx.content.charAt(j + 1);
if (c2 == '\\') {
if (j + 2 < to && ctx.content.charAt(j + 2) == '{')
++j; //skip '\\'
} else if (c2 == '{') {
addText(parent, sb);
j = parseEL(ctx, parent, j, to);
continue;
}
}
break;
case '\n':
++ctx.nLines;
}
sb.append(cc);
}
addText(parent, sb);
}
/** Parses a control (e.g., <% page %>) starting at from,
* and returns the position of '>' (in %>).
*/
private static int parseControl(Context ctx, Node parent, int from, int to)
throws DspException, IOException, XelException {
int j = from + 2;
if (j + 1 >= to)
throw new DspException(MWeb.DSP_ACTION_NOT_TERMINATED, new Object[] { null, new Integer(ctx.nLines) });
//0. comment
char cc = ctx.content.charAt(j);
if (cc == '-' && ctx.content.charAt(j + 1) == '-') { //comment
for (int end = to - 4;; ++j) {
if (j > end)
throw new DspException(MWeb.DSP_COMMENT_NOT_TERMINATED, new Integer(ctx.nLines));
if (ctx.content.charAt(j) == '\n')
++ctx.nLines;
else if (startsWith(ctx.content, j, to, "--%>"))
return j + 3;
}
}
if (cc != '@')
throw new DspException(MWeb.DSP_EXPECT_CHARACTER,
new Object[] { new Character('@'), new Integer(ctx.nLines) });
//1: which control
j = skipWhitespaces(ctx, j + 1, to);
int k = nextSeparator(ctx, j, to);
if (k >= to)
throw new DspException(MWeb.DSP_ACTION_NOT_TERMINATED, new Object[] { null, new Integer(ctx.nLines) });
final ActionNode action;
final String ctlnm = ctx.content.substring(j, k);
if ("taglib".equals(ctlnm)) {
action = null;
} else if ("page".equals(ctlnm)) {
ctx.pageDefined = true;
trim(parent); //Bug 1798123: avoid getOut being called before Page
parent.addChild(action = new ActionNode(Page.class, ctx.nLines));
} else {
throw new DspException(MWeb.DSP_UNKNOWN_ACTION, new Object[] { ctlnm, new Integer(ctx.nLines) });
}
//2: parse attributes
final Map<String, String> attrs = new HashMap<String, String>();
k = parseAttrs(ctx, attrs, ctlnm, k, to);
cc = ctx.content.charAt(k);
if (cc != '%')
throw new DspException(MWeb.DSP_EXPECT_CHARACTER,
new Object[] { new Character('%'), new Integer(ctx.nLines) });
if (action == null) { //taglib
final String uri = attrs.get("uri"), prefix = attrs.get("prefix");
if (prefix == null || uri == null)
throw new DspException(MWeb.DSP_TAGLIB_ATTRIBUTE_REQUIRED, new Integer(ctx.nLines));
ctx.loadTaglib(prefix, uri);
} else {
applyAttrs(ctlnm, action, attrs, ctx);
}
if (++k >= to || ctx.content.charAt(k) != '>')
throw new DspException(MWeb.DSP_ACTION_NOT_TERMINATED, new Object[] { ctlnm, new Integer(ctx.nLines) });
return k;
}
/** Trimmed {@link TextNode} that contains nothing but spaces.
*/
private static void trim(Node node) {
for (Iterator it = node.getChildren().iterator(); it.hasNext();) {
final Object o = it.next();
if (o instanceof TextNode) {
final String s = ((TextNode) o).getText();
if (s == null || s.trim().length() == 0)
it.remove();
}
}
}
/** Parses an action (e.g., <c:forEach...>...</c:forEach>).
* @param from the position of ':'
* @return the position of the last '>'.
*/
private static int parseAction(Context ctx, Node parent, String prefix, int from, int to)
throws DspException, IOException, XelException {
//1: which action
int j = skipWhitespaces(ctx, from + 1, to);
int k = nextSeparator(ctx, j, to);
if (k >= to)
throw new DspException(MWeb.DSP_ACTION_NOT_TERMINATED,
new Object[] { prefix + ':', new Integer(ctx.nLines) });
if (k == j)
throw new DspException(MWeb.DSP_ACTION_REQUIRED, new Integer(ctx.nLines));
final String actnm = ctx.content.substring(j, k);
final Class actcls = ctx.getActionClass(prefix, actnm);
if (actcls == null)
throw new DspException(MWeb.DSP_UNKNOWN_ACTION,
new Object[] { prefix + ':' + actnm, new Integer(ctx.nLines) });
final ActionNode action = new ActionNode(actcls, ctx.nLines);
parent.addChild(action);
//2: action's attributes
final Map<String, String> attrs = new HashMap<String, String>();
j = parseAttrs(ctx, attrs, actnm, k, to);
char cc = ctx.content.charAt(j);
boolean ended = cc == '/';
if (!ended && cc != '>')
throw new DspException(MWeb.DSP_UNEXPECT_CHARACTER,
new Object[] { new Character(cc), new Integer(ctx.nLines) });
applyAttrs(actnm, action, attrs, ctx);
if (ended) {
if (j + 1 >= to || ctx.content.charAt(j + 1) != '>')
throw new DspException(MWeb.DSP_ACTION_NOT_TERMINATED,
new Object[] { prefix + ':' + actnm, new Integer(action.getLineNumber()) });
return j + 1;
}
//3: nested content
final int nestedFrom = ++j, nestedTo;
for (int depth = 0;; ++j) {
if (j >= to)
throw new DspException(MWeb.DSP_ACTION_NOT_TERMINATED,
new Object[] { actnm, new Integer(action.getLineNumber()) });
cc = ctx.content.charAt(j);
if (j + 1 < to) {
if (cc == '<') {
final int oldLines = ctx.nLines;
k = j + 1;
ended = ctx.content.charAt(k) == '/';
k = skipWhitespaces(ctx, ended ? k + 1 : k, to);
int l = nextSeparator(ctx, k, to);
if (l >= to || ctx.content.charAt(l) != ':' || !prefix.equals(ctx.content.substring(k, l))) {
ctx.nLines = oldLines;
continue; //bypass
}
k = skipWhitespaces(ctx, l + 1, to);
l = nextSeparator(ctx, k, to);
if (l >= to || !actnm.equals(ctx.content.substring(k, l))) {
ctx.nLines = oldLines;
continue; //bypass
}
l = skipWhitespaces(ctx, l, to);
if (l >= to || (ended && ctx.content.charAt(l) != '>')) {
ctx.nLines = oldLines;
continue; //bypass
}
if (ended) {
if (--depth < 0) {
nestedTo = j;
j = l;
break; //done
}
} else {
++depth;
}
j = l;
continue;
} else if (cc == '$' && ctx.content.charAt(j + 1) == '{') {
j = endOfEL(ctx, j, to);
continue;
}
}
if (cc == '\n')
++ctx.nLines;
}
parse0(ctx, action, nestedFrom, nestedTo); //recursive
return j;
}
private static boolean startsWith(String content, int from, int to, String s) {
for (int j = 0, len = s.length();; ++from, ++j) {
if (j >= len)
return true;
if (from >= to || content.charAt(from) != s.charAt(j))
return false;
}
}
private static int skipWhitespaces(Context ctx, int from, int to) {
for (; from < to; ++from) {
final char cc = ctx.content.charAt(from);
if (cc == '\n')
++ctx.nLines;
else if (!Character.isWhitespace(cc))
break;
}
return from;
}
private static int nextSeparator(Context ctx, int from, int to) {
for (; from < to; ++from) {
final char cc = ctx.content.charAt(from);
if ((cc < '0' || cc > '9') && (cc < 'a' || cc > 'z') && (cc < 'A' || cc > 'Z') && cc != '_')
break;
}
return from;
}
/** Parses the attributes.
*/
private static int parseAttrs(Context ctx, Map<String, String> attrs, String actnm, int from, int to)
throws DspException {
for (int j, k = from;;) {
j = skipWhitespaces(ctx, k, to);
k = nextSeparator(ctx, j, to);
if (k >= to)
throw new DspException(MWeb.DSP_ACTION_NOT_TERMINATED, new Object[] { actnm, new Integer(ctx.nLines) });
if (j == k)
return j;
final String attrnm = ctx.content.substring(j, k);
k = skipWhitespaces(ctx, k, to);
j = skipWhitespaces(ctx, k + 1, to);
if (j >= to || ctx.content.charAt(k) != '=')
throw new DspException(MWeb.DSP_ATTRIBUTE_VALUE_REQUIRED,
new Object[] { actnm, attrnm, new Integer(ctx.nLines) });
final char quot = ctx.content.charAt(j);
if (quot != '"' && quot != '\'')
throw new DspException(MWeb.DSP_ATTRIBUTE_VALUE_QUOTE_REQUIRED,
new Object[] { actnm, attrnm, new Integer(ctx.nLines) });
final StringBuffer sbval = new StringBuffer();
for (k = ++j;; ++k) {
if (k >= to)
throw new DspException(MWeb.DSP_ATTRIBUTE_VALUE_QUOTE_REQUIRED,
new Object[] { actnm, attrnm, new Integer(ctx.nLines) });
final char cc = ctx.content.charAt(k);
if (cc == '\n')
throw new DspException(MWeb.DSP_ATTRIBUTE_VALUE_QUOTE_REQUIRED,
new Object[] { actnm, attrnm, new Integer(ctx.nLines) });
if (cc == quot) {
++k;
break; //found
}
sbval.append(cc);
if (cc == '\\' && ++k < to)
sbval.setCharAt(sbval.length() - 1, ctx.content.charAt(k));
}
attrs.put(attrnm, sbval.toString());
}
}
/** Applies attributes.
*/
private static final void applyAttrs(String actnm, ActionNode action, Map<String, String> attrs, ParseContext ctx)
throws DspException, XelException {
for (Map.Entry<String, String> me : attrs.entrySet()) {
final String attrnm = me.getKey();
final String attrval = me.getValue();
try {
action.addAttribute(attrnm, attrval, ctx);
} catch (NoSuchMethodException ex) {
throw new DspException(MWeb.DSP_ATTRIBUTE_NOT_FOUND,
new Object[] { actnm, attrnm, new Integer(action.getLineNumber()) });
} catch (ClassCastException ex) {
throw new DspException(MWeb.DSP_ATTRIBUTE_INVALID_VALUE,
new Object[] { actnm, attrnm, attrval, new Integer(action.getLineNumber()) }, ex);
}
}
}
/** Parses an EL expression starting at from.
* @return the position of }.
*/
private static int parseEL(Context ctx, Node parent, int from, int to) throws DspException, XelException {
int j = endOfEL(ctx, from, to); //point to }
parent.addChild(new XelNode(ctx.content.substring(from, j + 1), ctx));
return j;
}
/** Returns the position of '}'. */
private static int endOfEL(Context ctx, int from, int to) throws DspException {
for (int j = from + 2;; ++j) {
if (j >= to)
throw new DspException(MWeb.EL_NOT_TERMINATED, new Integer(ctx.nLines));
final char cc = ctx.content.charAt(j);
if (cc == '}') {
return j;
} else if (cc == '\'' || cc == '"') {
while (++j < to) {
final char c2 = ctx.content.charAt(j);
if (c2 == cc)
break;
if (cc == '\n')
throw new DspException("Illegal EL expression: non-terminaled " + cc + " at line " + ctx.nLines
+ " character " + j);
if (c2 == '\\' && ++j < to && ctx.content.charAt(j) == '\n')
++ctx.nLines;
}
} else if (cc == '\n') {
++ctx.nLines;
}
}
}
/** Adds a text node. */
private static void addText(Node parent, StringBuffer sb) {
if (sb.length() > 0) {
parent.addChild(new TextNode(sb.toString()));
sb.setLength(0);
}
}
/** Context used for parsing. */
private static class Context implements ParseContext {
private final String content;
/** (String prefix, Map(String name, Class class)). */
private final Map<String, Map<String, Class<?>>> _actions = new HashMap<String, Map<String, Class<?>>>();
private final Locator _locator;
private final ExpressionFactory _xelf;
private final SimpleMapper _mapper;
private final VariableResolver _resolver;
private Map<String, Object> _attrs;
private int nLines;
/** Whether the page action is defined. */
private boolean pageDefined;
//ParseContext//
public ExpressionFactory getExpressionFactory() {
return _xelf;
}
public VariableResolver getVariableResolver() {
return _resolver;
}
public FunctionMapper getFunctionMapper() {
return _mapper;
}
//Internal//
private Context(String content, XelContext xelc, Locator loc) {
this.content = content;
_resolver = xelc != null ? xelc.getVariableResolver() : null;
_mapper = new SimpleMapper(xelc != null ? xelc.getFunctionMapper() : null);
_xelf = Expressions.newExpressionFactory();
_locator = loc;
this.nLines = 1;
}
private boolean hasPrefix(String prefix) {
return _actions.containsKey(prefix);
}
private Class<?> getActionClass(String prefix, String actnm) {
final Map<String, Class<?>> acts = _actions.get(prefix);
return acts != null ? acts.get(actnm) : null;
}
private void loadTaglib(String prefix, String uri) throws DspException, IOException {
if (_locator == null)
throw new DspException("Unable to load " + uri + " because locator is not specified");
URL url = uri.indexOf("://") > 0 ? null : _locator.getResource(uri);
if (url == null) {
url = Taglibs.getDefaultURL(uri);
if (url == null)
throw new FileNotFoundException(uri);
}
try {
loadTaglib0(prefix, url);
} catch (IOException ex) {
throw ex;
} catch (Exception ex) {
throw DspException.Aide.wrap(ex);
}
}
private void loadTaglib0(String prefix, URL url) throws Exception {
final Element root = new SAXBuilder(true, false, true).build(url).getRootElement();
_mapper.load(prefix, url);
final Map<String, Class<?>> acts = new HashMap<String, Class<?>>();
for (Iterator it = root.getElements("tag").iterator(); it.hasNext();) {
final Element e = (Element) it.next();
final String name = IDOMs.getRequiredElementValue(e, "name");
final String clsName = IDOMs.getRequiredElementValue(e, "tag-class");
final Class<?> cls = Classes.forNameByThread(clsName);
if (!Action.class.isAssignableFrom(cls))
throw new DspException(cls + " doesn't implement " + Action.class);
acts.put(name, cls);
}
if (!acts.isEmpty())
_actions.put(prefix, acts);
}
private Map<String, Object> attrs() {
return _attrs != null ? _attrs : (_attrs = new HashMap<String, Object>());
}
public Object getAttribute(String name) {
return _attrs != null ? _attrs.get(name) : null;
}
public Object setAttribute(String name, Object value) {
return attrs().put(name, value);
}
public boolean hasAttribute(String name) {
return _attrs != null && _attrs.containsKey(name);
}
public Object removeAttribute(String name) {
return _attrs != null ? _attrs.remove(name) : null;
}
public Map<String, Object> getAttributes() {
return attrs();
}
}
}