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package org.apache.jasper.compiler;
import java.util.*;
import javax.servlet.jsp.tagext.FunctionInfo;
import org.apache.jasper.JasperException;
/**
* This class generates functions mappers for the EL expressions in the page.
* Instead of a global mapper, a mapper is used for ecah call to EL
* evaluator, thus avoiding the prefix overlapping and redefinition
* issues.
*
* @author Kin-man Chung
*/
public class ELFunctionMapper {
private int currFunc = 0;
StringBuilder ds; // Contains codes to initialize the functions mappers.
StringBuilder ss; // Contains declarations of the functions mappers.
/**
* Creates the functions mappers for all EL expressions in the JSP page.
*
* @param compiler Current compiler, mainly for accessing error dispatcher.
* @param page The current compilation unit.
*/
public static void map(Compiler compiler, Node.Nodes page)
throws JasperException {
ELFunctionMapper map = new ELFunctionMapper();
map.ds = new StringBuilder();
map.ss = new StringBuilder();
page.visit(map.new ELFunctionVisitor());
// Append the declarations to the root node
String ds = map.ds.toString();
if (ds.length() > 0) {
Node root = page.getRoot();
new Node.Declaration(map.ss.toString(), null, root);
new Node.Declaration("static {\n" + ds + "}\n", null, root);
}
}
/**
* A visitor for the page. The places where EL is allowed are scanned
* for functions, and if found functions mappers are created.
*/
class ELFunctionVisitor extends Node.Visitor {
/**
* Use a global name map to facilitate reuse of function maps.
* The key used is prefix:function:uri.
*/
private HashMap<String, String> gMap = new HashMap<String, String>();
public void visit(Node.ParamAction n) throws JasperException {
doMap(n.getValue());
visitBody(n);
}
public void visit(Node.IncludeAction n) throws JasperException {
doMap(n.getPage());
visitBody(n);
}
public void visit(Node.ForwardAction n) throws JasperException {
doMap(n.getPage());
visitBody(n);
}
public void visit(Node.SetProperty n) throws JasperException {
doMap(n.getValue());
visitBody(n);
}
public void visit(Node.UseBean n) throws JasperException {
doMap(n.getBeanName());
visitBody(n);
}
public void visit(Node.PlugIn n) throws JasperException {
doMap(n.getHeight());
doMap(n.getWidth());
visitBody(n);
}
public void visit(Node.JspElement n) throws JasperException {
Node.JspAttribute[] attrs = n.getJspAttributes();
for (int i = 0; attrs != null && i < attrs.length; i++) {
doMap(attrs[i]);
}
doMap(n.getNameAttribute());
visitBody(n);
}
public void visit(Node.UninterpretedTag n) throws JasperException {
Node.JspAttribute[] attrs = n.getJspAttributes();
for (int i = 0; attrs != null && i < attrs.length; i++) {
doMap(attrs[i]);
}
visitBody(n);
}
public void visit(Node.CustomTag n) throws JasperException {
Node.JspAttribute[] attrs = n.getJspAttributes();
for (int i = 0; attrs != null && i < attrs.length; i++) {
doMap(attrs[i]);
}
visitBody(n);
}
public void visit(Node.ELExpression n) throws JasperException {
doMap(n.getEL());
}
private void doMap(Node.JspAttribute attr)
throws JasperException {
if (attr != null) {
doMap(attr.getEL());
}
}
/**
* Creates function mappers, if needed, from ELNodes
*/
private void doMap(ELNode.Nodes el)
throws JasperException {
// Only care about functions in ELNode's
class Fvisitor extends ELNode.Visitor {
ArrayList<ELNode.Function> funcs =
new ArrayList<ELNode.Function>();
Set<String> keys = new HashSet<String>();
public void visit(ELNode.Function n) throws JasperException {
if (n.getUri() == null) {
// Can be a lambda expresion call
return;
}
String key = n.getPrefix() + ":" + n.getName();
if (! keys.contains(key)) {
keys.add(key);
funcs.add(n);
}
}
}
if (el == null) {
return;
}
// First locate all unique functions in this EL
Fvisitor fv = new Fvisitor();
el.visit(fv);
ArrayList<ELNode.Function> functions = fv.funcs;
if (functions.size() == 0) {
return;
}
// Reuse a previous map if possible
String decName = matchMap(functions);
if (decName != null) {
el.setMapName(decName);
return;
}
// Generate declaration for the map statically
decName = getMapName();
ss.append("static private org.apache.jasper.runtime.ProtectedFunctionMapper " + decName + ";\n");
ds.append(" " + decName + "= ");
ds.append("org.apache.jasper.runtime.ProtectedFunctionMapper");
// Special case if there is only one function in the map
String funcMethod = null;
if (functions.size() == 1) {
funcMethod = ".getMapForFunction";
} else {
ds.append(".getInstance();\n");
funcMethod = " " + decName + ".mapFunction";
}
// Setup arguments for either getMapForFunction or mapFunction
for (int i = 0; i < functions.size(); i++) {
ELNode.Function f = (ELNode.Function)functions.get(i);
FunctionInfo funcInfo = f.getFunctionInfo();
String key = f.getPrefix()+ ":" + f.getName();
ds.append(funcMethod + "(\"" + key + "\", " +
funcInfo.getFunctionClass() + ".class, " +
'\"' + f.getMethodName() + "\", " +
"new Class[] {");
String params[] = f.getParameters();
for (int k = 0; k < params.length; k++) {
if (k != 0) {
ds.append(", ");
}
int iArray = params[k].indexOf('[');
if (iArray < 0) {
ds.append(params[k] + ".class");
}
else {
String baseType = params[k].substring(0, iArray);
ds.append("java.lang.reflect.Array.newInstance(");
ds.append(baseType);
ds.append(".class,");
// Count the number of array dimension
int aCount = 0;
for (int jj = iArray; jj < params[k].length(); jj++ ) {
if (params[k].charAt(jj) == '[') {
aCount++;
}
}
if (aCount == 1) {
ds.append("0).getClass()");
} else {
ds.append("new int[" + aCount + "]).getClass()");
}
}
}
ds.append("});\n");
// Put the current name in the global function map
gMap.put(f.getPrefix() + ':' + f.getName() + ':' + f.getUri(),
decName);
}
el.setMapName(decName);
}
/**
* Find the name of the function mapper for an EL. Reuse a
* previously generated one if possible.
* @param functions An ArrayList of ELNode.Function instances that
* represents the functions in an EL
* @return A previous generated function mapper name that can be used
* by this EL; null if none found.
*/
private String matchMap(ArrayList<ELNode.Function> functions) {
String mapName = null;
for (int i = 0; i < functions.size(); i++) {
ELNode.Function f = functions.get(i);
String temName = gMap.get(f.getPrefix() + ':' +
f.getName() + ':' + f.getUri());
if (temName == null) {
return null;
}
if (mapName == null) {
mapName = temName;
} else if (!temName.equals(mapName)) {
// If not all in the previous match, then no match.
return null;
}
}
return mapName;
}
/*
* @return An unique name for a function mapper.
*/
private String getMapName() {
return "_jspx_fnmap_" + currFunc++;
}
}
}