1 /*
2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
3 * @LastModified: Oct 2017
4 */
5 /*
6 * Licensed to the Apache Software Foundation (ASF) under one or more
7 * contributor license agreements. See the NOTICE file distributed with
8 * this work for additional information regarding copyright ownership.
9 * The ASF licenses this file to You under the Apache License, Version 2.0
10 * (the "License"); you may not use this file except in compliance with
11 * the License. You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 * See the License for the specific language governing permissions and
19 * limitations under the License.
20 */
21
22 package com.sun.org.apache.xpath.internal.operations;
23
24 import com.sun.org.apache.xalan.internal.res.XSLMessages;
25 import com.sun.org.apache.xml.internal.utils.QName;
26 import com.sun.org.apache.xpath.internal.Expression;
27 import com.sun.org.apache.xpath.internal.ExpressionOwner;
28 import com.sun.org.apache.xpath.internal.XPathContext;
29 import com.sun.org.apache.xpath.internal.XPathVisitor;
30 import com.sun.org.apache.xpath.internal.axes.PathComponent;
31 import com.sun.org.apache.xpath.internal.axes.WalkerFactory;
32 import com.sun.org.apache.xpath.internal.objects.XNodeSet;
33 import com.sun.org.apache.xpath.internal.objects.XObject;
34 import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;
35 import java.util.List;
36 import javax.xml.transform.TransformerException;
37
38
39 /**
40 * The variable reference expression executer.
41 */
42 public class Variable extends Expression implements PathComponent
43 {
44 static final long serialVersionUID = -4334975375609297049L;
45 /** Tell if fixupVariables was called.
46 * @serial */
47 private boolean m_fixUpWasCalled = false;
48
49 /** The qualified name of the variable.
50 * @serial */
51 protected QName m_qname;
52
53 /**
54 * The index of the variable, which is either an absolute index to a
55 * global, or, if higher than the globals area, must be adjusted by adding
56 * the offset to the current stack frame.
57 */
58 protected int m_index;
59
60 /**
61 * Set the index for the variable into the stack. For advanced use only. You
62 * must know what you are doing to use this.
63 *
64 * @param index a global or local index.
65 */
66 public void setIndex(int index)
67 {
68 m_index = index;
69 }
70
71 /**
72 * Set the index for the variable into the stack. For advanced use only.
73 *
74 * @return index a global or local index.
75 */
76 public int getIndex()
77 {
78 return m_index;
79 }
80
81 /**
82 * Set whether or not this is a global reference. For advanced use only.
83 *
84 * @param isGlobal true if this should be a global variable reference.
85 */
86 public void setIsGlobal(boolean isGlobal)
87 {
88 m_isGlobal = isGlobal;
89 }
90
91 /**
92 * Set the index for the variable into the stack. For advanced use only.
93 *
94 * @return true if this should be a global variable reference.
95 */
96 public boolean getGlobal()
97 {
98 return m_isGlobal;
99 }
100
101
102
103
104
105 protected boolean m_isGlobal = false;
106
107 /**
108 * This function is used to fixup variables from QNames to stack frame
109 * indexes at stylesheet build time.
110 * @param vars List of QNames that correspond to variables. This list
111 * should be searched backwards for the first qualified name that
112 * corresponds to the variable reference qname. The position of the
113 * QName in the vector from the start of the vector will be its position
114 * in the stack frame (but variables above the globalsTop value will need
115 * to be offset to the current stack frame).
116 */
117 public void fixupVariables(List<QName> vars, int globalsSize)
118 {
119 m_fixUpWasCalled = true;
120 int sz = vars.size();
121
122 for (int i = vars.size()-1; i >= 0; i--)
123 {
124 QName qn = vars.get(i);
125 // System.out.println("qn: "+qn);
126 if(qn.equals(m_qname))
127 {
128
129 if(i < globalsSize)
130 {
131 m_isGlobal = true;
132 m_index = i;
133 }
134 else
135 {
136 m_index = i-globalsSize;
137 }
138
139 return;
140 }
141 }
142
143 java.lang.String msg = XSLMessages.createXPATHMessage(XPATHErrorResources.ER_COULD_NOT_FIND_VAR,
144 new Object[]{m_qname.toString()});
145
146 TransformerException te = new TransformerException(msg, this);
147
148 throw new com.sun.org.apache.xml.internal.utils.WrappedRuntimeException(te);
149
150 }
151
152
153 /**
154 * Set the qualified name of the variable.
155 *
156 * @param qname Must be a non-null reference to a qualified name.
157 */
158 public void setQName(QName qname)
159 {
160 m_qname = qname;
161 }
162
163 /**
164 * Get the qualified name of the variable.
165 *
166 * @return A non-null reference to a qualified name.
167 */
168 public QName getQName()
169 {
170 return m_qname;
171 }
172
173 /**
174 * Execute an expression in the XPath runtime context, and return the
175 * result of the expression.
176 *
177 *
178 * @param xctxt The XPath runtime context.
179 *
180 * @return The result of the expression in the form of a <code>XObject</code>.
181 *
182 * @throws javax.xml.transform.TransformerException if a runtime exception
183 * occurs.
184 */
185 public XObject execute(XPathContext xctxt)
186 throws javax.xml.transform.TransformerException
187 {
188 return execute(xctxt, false);
189 }
190
191
192 /**
193 * Dereference the variable, and return the reference value. Note that lazy
194 * evaluation will occur. If a variable within scope is not found, a warning
195 * will be sent to the error listener, and an empty nodeset will be returned.
196 *
197 *
198 * @param xctxt The runtime execution context.
199 *
200 * @return The evaluated variable, or an empty nodeset if not found.
201 *
202 * @throws javax.xml.transform.TransformerException
203 */
204 public XObject execute(XPathContext xctxt, boolean destructiveOK) throws javax.xml.transform.TransformerException
205 {
206 com.sun.org.apache.xml.internal.utils.PrefixResolver xprefixResolver = xctxt.getNamespaceContext();
207
208 XObject result;
209 // Is the variable fetched always the same?
210 // XObject result = xctxt.getVariable(m_qname);
211 if(m_fixUpWasCalled)
212 {
213 if(m_isGlobal)
214 result = xctxt.getVarStack().getGlobalVariable(xctxt, m_index, destructiveOK);
215 else
216 result = xctxt.getVarStack().getLocalVariable(xctxt, m_index, destructiveOK);
217 }
218 else {
219 result = xctxt.getVarStack().getVariableOrParam(xctxt,m_qname);
220 }
221
222 if (null == result)
223 {
224 // This should now never happen...
225 warn(xctxt, XPATHErrorResources.WG_ILLEGAL_VARIABLE_REFERENCE,
226 new Object[]{ m_qname.getLocalPart() }); //"VariableReference given for variable out "+
227 // (new RuntimeException()).printStackTrace();
228 // error(xctxt, XPATHErrorResources.ER_COULDNOT_GET_VAR_NAMED,
229 // new Object[]{ m_qname.getLocalPart() }); //"Could not get variable named "+varName);
230
231 result = new XNodeSet(xctxt.getDTMManager());
232 }
233
234 return result;
235 // }
236 // else
237 // {
238 // // Hack city... big time. This is needed to evaluate xpaths from extensions,
239 // // pending some bright light going off in my head. Some sort of callback?
240 // synchronized(this)
241 // {
242 // com.sun.org.apache.xalan.internal.templates.ElemVariable vvar= getElemVariable();
243 // if(null != vvar)
244 // {
245 // m_index = vvar.getIndex();
246 // m_isGlobal = vvar.getIsTopLevel();
247 // m_fixUpWasCalled = true;
248 // return execute(xctxt);
249 // }
250 // }
251 // throw new javax.xml.transform.TransformerException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_VAR_NOT_RESOLVABLE, new Object[]{m_qname.toString()})); //"Variable not resolvable: "+m_qname);
252 // }
253 }
254
255 /**
256 * Get the XSLT ElemVariable that this sub-expression references. In order for
257 * this to work, the SourceLocator must be the owning ElemTemplateElement.
258 * @return The dereference to the ElemVariable, or null if not found.
259 */
260 // J2SE does not support Xalan interpretive
261 /*
262 public com.sun.org.apache.xalan.internal.templates.ElemVariable getElemVariable()
263 {
264
265 // Get the current ElemTemplateElement, and then walk backwards in
266 // document order, searching
267 // for an xsl:param element or xsl:variable element that matches our
268 // qname. If we reach the top level, use the StylesheetRoot's composed
269 // list of top level variables and parameters.
270
271 com.sun.org.apache.xalan.internal.templates.ElemVariable vvar = null;
272 com.sun.org.apache.xpath.internal.ExpressionNode owner = getExpressionOwner();
273
274 if (null != owner && owner instanceof com.sun.org.apache.xalan.internal.templates.ElemTemplateElement)
275 {
276
277 com.sun.org.apache.xalan.internal.templates.ElemTemplateElement prev =
278 (com.sun.org.apache.xalan.internal.templates.ElemTemplateElement) owner;
279
280 if (!(prev instanceof com.sun.org.apache.xalan.internal.templates.Stylesheet))
281 {
282 while ( prev != null && !(prev.getParentNode() instanceof com.sun.org.apache.xalan.internal.templates.Stylesheet) )
283 {
284 com.sun.org.apache.xalan.internal.templates.ElemTemplateElement savedprev = prev;
285
286 while (null != (prev = prev.getPreviousSiblingElem()))
287 {
288 if(prev instanceof com.sun.org.apache.xalan.internal.templates.ElemVariable)
289 {
290 vvar = (com.sun.org.apache.xalan.internal.templates.ElemVariable) prev;
291
292 if (vvar.getName().equals(m_qname))
293 {
294 return vvar;
295 }
296 vvar = null;
297 }
298 }
299 prev = savedprev.getParentElem();
300 }
301 }
302 if (prev != null)
303 vvar = prev.getStylesheetRoot().getVariableOrParamComposed(m_qname);
304 }
305 return vvar;
306
307 }
308 */
309 /**
310 * Tell if this expression returns a stable number that will not change during
311 * iterations within the expression. This is used to determine if a proximity
312 * position predicate can indicate that no more searching has to occur.
313 *
314 *
315 * @return true if the expression represents a stable number.
316 */
317 public boolean isStableNumber()
318 {
319 return true;
320 }
321
322 /**
323 * Get the analysis bits for this walker, as defined in the WalkerFactory.
324 * @return One of WalkerFactory#BIT_DESCENDANT, etc.
325 */
326 public int getAnalysisBits()
327 {
328
329 // J2SE does not support Xalan interpretive
330 /*
331 com.sun.org.apache.xalan.internal.templates.ElemVariable vvar = getElemVariable();
332 if(null != vvar)
333 {
334 XPath xpath = vvar.getSelect();
335 if(null != xpath)
336 {
337 Expression expr = xpath.getExpression();
338 if(null != expr && expr instanceof PathComponent)
339 {
340 return ((PathComponent)expr).getAnalysisBits();
341 }
342 }
343 }
344 */
345
346 return WalkerFactory.BIT_FILTER;
347 }
348
349
350 /**
351 * @see com.sun.org.apache.xpath.internal.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
352 */
353 public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
354 {
355 visitor.visitVariableRef(owner, this);
356 }
357 /**
358 * @see Expression#deepEquals(Expression)
359 */
360 public boolean deepEquals(Expression expr)
361 {
362 if(!isSameClass(expr))
363 return false;
364
365 if(!m_qname.equals(((Variable)expr).m_qname))
366 return false;
367
368 // J2SE does not support Xalan interpretive
369 /*
370 // We have to make sure that the qname really references
371 // the same variable element.
372 if(getElemVariable() != ((Variable)expr).getElemVariable())
373 return false;
374 */
375
376 return true;
377 }
378
379 static final java.lang.String PSUEDOVARNAMESPACE = "http://xml.apache.org/xalan/psuedovar";
380
381 /**
382 * Tell if this is a psuedo variable reference, declared by Xalan instead
383 * of by the user.
384 */
385 public boolean isPsuedoVarRef()
386 {
387 java.lang.String ns = m_qname.getNamespaceURI();
388 if((null != ns) && ns.equals(PSUEDOVARNAMESPACE))
389 {
390 if(m_qname.getLocalName().startsWith("#"))
391 return true;
392 }
393 return false;
394 }
395
396
397 }