1 /*
2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
3 */
4 /*
5 * Licensed to the Apache Software Foundation (ASF) under one or more
6 * contributor license agreements. See the NOTICE file distributed with
7 * this work for additional information regarding copyright ownership.
8 * The ASF licenses this file to You under the Apache License, Version 2.0
9 * (the "License"); you may not use this file except in compliance with
10 * the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS,
16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
19 */
20
21 package com.sun.org.apache.xpath.internal.operations;
22
23 import com.sun.org.apache.xalan.internal.res.XSLMessages;
24 import com.sun.org.apache.xml.internal.utils.QName;
25 import com.sun.org.apache.xpath.internal.Expression;
26 import com.sun.org.apache.xpath.internal.ExpressionOwner;
27 import com.sun.org.apache.xpath.internal.XPathContext;
28 import com.sun.org.apache.xpath.internal.XPathVisitor;
29 import com.sun.org.apache.xpath.internal.axes.PathComponent;
30 import com.sun.org.apache.xpath.internal.axes.WalkerFactory;
31 import com.sun.org.apache.xpath.internal.objects.XNodeSet;
32 import com.sun.org.apache.xpath.internal.objects.XObject;
33 import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;
34 import java.util.List;
35 import javax.xml.transform.TransformerException;
36
37
38 /**
39 * The variable reference expression executer.
40 *
41 * @LastModified: Oct 2017
42 */
43 public class Variable extends Expression implements PathComponent
44 {
45 static final long serialVersionUID = -4334975375609297049L;
46 /** Tell if fixupVariables was called.
47 * @serial */
48 private boolean m_fixUpWasCalled = false;
49
50 /** The qualified name of the variable.
51 * @serial */
52 protected QName m_qname;
53
54 /**
55 * The index of the variable, which is either an absolute index to a
56 * global, or, if higher than the globals area, must be adjusted by adding
57 * the offset to the current stack frame.
58 */
59 protected int m_index;
60
61 /**
62 * Set the index for the variable into the stack. For advanced use only. You
63 * must know what you are doing to use this.
64 *
65 * @param index a global or local index.
66 */
67 public void setIndex(int index)
68 {
69 m_index = index;
70 }
71
72 /**
73 * Set the index for the variable into the stack. For advanced use only.
74 *
75 * @return index a global or local index.
76 */
77 public int getIndex()
78 {
79 return m_index;
80 }
81
82 /**
83 * Set whether or not this is a global reference. For advanced use only.
84 *
85 * @param isGlobal true if this should be a global variable reference.
86 */
87 public void setIsGlobal(boolean isGlobal)
88 {
89 m_isGlobal = isGlobal;
90 }
91
92 /**
93 * Set the index for the variable into the stack. For advanced use only.
94 *
95 * @return true if this should be a global variable reference.
96 */
97 public boolean getGlobal()
98 {
99 return m_isGlobal;
100 }
101
102
103
104
105
106 protected boolean m_isGlobal = false;
107
108 /**
109 * This function is used to fixup variables from QNames to stack frame
110 * indexes at stylesheet build time.
111 * @param vars List of QNames that correspond to variables. This list
112 * should be searched backwards for the first qualified name that
113 * corresponds to the variable reference qname. The position of the
114 * QName in the vector from the start of the vector will be its position
115 * in the stack frame (but variables above the globalsTop value will need
116 * to be offset to the current stack frame).
117 */
118 public void fixupVariables(List<QName> vars, int globalsSize)
119 {
120 m_fixUpWasCalled = true;
121 int sz = vars.size();
122
123 for (int i = vars.size()-1; i >= 0; i--)
124 {
125 QName qn = vars.get(i);
126 // System.out.println("qn: "+qn);
127 if(qn.equals(m_qname))
128 {
129
130 if(i < globalsSize)
131 {
132 m_isGlobal = true;
133 m_index = i;
134 }
135 else
136 {
137 m_index = i-globalsSize;
138 }
139
140 return;
141 }
142 }
143
144 java.lang.String msg = XSLMessages.createXPATHMessage(XPATHErrorResources.ER_COULD_NOT_FIND_VAR,
145 new Object[]{m_qname.toString()});
146
147 TransformerException te = new TransformerException(msg, this);
148
149 throw new com.sun.org.apache.xml.internal.utils.WrappedRuntimeException(te);
150
151 }
152
153
154 /**
155 * Set the qualified name of the variable.
156 *
157 * @param qname Must be a non-null reference to a qualified name.
158 */
159 public void setQName(QName qname)
160 {
161 m_qname = qname;
162 }
163
164 /**
165 * Get the qualified name of the variable.
166 *
167 * @return A non-null reference to a qualified name.
168 */
169 public QName getQName()
170 {
171 return m_qname;
172 }
173
174 /**
175 * Execute an expression in the XPath runtime context, and return the
176 * result of the expression.
177 *
178 *
179 * @param xctxt The XPath runtime context.
180 *
181 * @return The result of the expression in the form of a <code>XObject</code>.
182 *
183 * @throws javax.xml.transform.TransformerException if a runtime exception
184 * occurs.
185 */
186 public XObject execute(XPathContext xctxt)
187 throws javax.xml.transform.TransformerException
188 {
189 return execute(xctxt, false);
190 }
191
192
193 /**
194 * Dereference the variable, and return the reference value. Note that lazy
195 * evaluation will occur. If a variable within scope is not found, a warning
196 * will be sent to the error listener, and an empty nodeset will be returned.
197 *
198 *
199 * @param xctxt The runtime execution context.
200 *
201 * @return The evaluated variable, or an empty nodeset if not found.
202 *
203 * @throws javax.xml.transform.TransformerException
204 */
205 public XObject execute(XPathContext xctxt, boolean destructiveOK) throws javax.xml.transform.TransformerException
206 {
207 com.sun.org.apache.xml.internal.utils.PrefixResolver xprefixResolver = xctxt.getNamespaceContext();
208
209 XObject result;
210 // Is the variable fetched always the same?
211 // XObject result = xctxt.getVariable(m_qname);
212 if(m_fixUpWasCalled)
213 {
214 if(m_isGlobal)
215 result = xctxt.getVarStack().getGlobalVariable(xctxt, m_index, destructiveOK);
216 else
217 result = xctxt.getVarStack().getLocalVariable(xctxt, m_index, destructiveOK);
218 }
219 else {
220 result = xctxt.getVarStack().getVariableOrParam(xctxt,m_qname);
221 }
222
223 if (null == result)
224 {
225 // This should now never happen...
226 warn(xctxt, XPATHErrorResources.WG_ILLEGAL_VARIABLE_REFERENCE,
227 new Object[]{ m_qname.getLocalPart() }); //"VariableReference given for variable out "+
228 // (new RuntimeException()).printStackTrace();
229 // error(xctxt, XPATHErrorResources.ER_COULDNOT_GET_VAR_NAMED,
230 // new Object[]{ m_qname.getLocalPart() }); //"Could not get variable named "+varName);
231
232 result = new XNodeSet(xctxt.getDTMManager());
233 }
234
235 return result;
236 // }
237 // else
238 // {
239 // // Hack city... big time. This is needed to evaluate xpaths from extensions,
240 // // pending some bright light going off in my head. Some sort of callback?
241 // synchronized(this)
242 // {
243 // com.sun.org.apache.xalan.internal.templates.ElemVariable vvar= getElemVariable();
244 // if(null != vvar)
245 // {
246 // m_index = vvar.getIndex();
247 // m_isGlobal = vvar.getIsTopLevel();
248 // m_fixUpWasCalled = true;
249 // return execute(xctxt);
250 // }
251 // }
252 // throw new javax.xml.transform.TransformerException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_VAR_NOT_RESOLVABLE, new Object[]{m_qname.toString()})); //"Variable not resolvable: "+m_qname);
253 // }
254 }
255
256 /**
257 * Get the XSLT ElemVariable that this sub-expression references. In order for
258 * this to work, the SourceLocator must be the owning ElemTemplateElement.
259 * @return The dereference to the ElemVariable, or null if not found.
260 */
261 // J2SE does not support Xalan interpretive
262 /*
263 public com.sun.org.apache.xalan.internal.templates.ElemVariable getElemVariable()
264 {
265
266 // Get the current ElemTemplateElement, and then walk backwards in
267 // document order, searching
268 // for an xsl:param element or xsl:variable element that matches our
269 // qname. If we reach the top level, use the StylesheetRoot's composed
270 // list of top level variables and parameters.
271
272 com.sun.org.apache.xalan.internal.templates.ElemVariable vvar = null;
273 com.sun.org.apache.xpath.internal.ExpressionNode owner = getExpressionOwner();
274
275 if (null != owner && owner instanceof com.sun.org.apache.xalan.internal.templates.ElemTemplateElement)
276 {
277
278 com.sun.org.apache.xalan.internal.templates.ElemTemplateElement prev =
279 (com.sun.org.apache.xalan.internal.templates.ElemTemplateElement) owner;
280
281 if (!(prev instanceof com.sun.org.apache.xalan.internal.templates.Stylesheet))
282 {
283 while ( prev != null && !(prev.getParentNode() instanceof com.sun.org.apache.xalan.internal.templates.Stylesheet) )
284 {
285 com.sun.org.apache.xalan.internal.templates.ElemTemplateElement savedprev = prev;
286
287 while (null != (prev = prev.getPreviousSiblingElem()))
288 {
289 if(prev instanceof com.sun.org.apache.xalan.internal.templates.ElemVariable)
290 {
291 vvar = (com.sun.org.apache.xalan.internal.templates.ElemVariable) prev;
292
293 if (vvar.getName().equals(m_qname))
294 {
295 return vvar;
296 }
297 vvar = null;
298 }
299 }
300 prev = savedprev.getParentElem();
301 }
302 }
303 if (prev != null)
304 vvar = prev.getStylesheetRoot().getVariableOrParamComposed(m_qname);
305 }
306 return vvar;
307
308 }
309 */
310 /**
311 * Tell if this expression returns a stable number that will not change during
312 * iterations within the expression. This is used to determine if a proximity
313 * position predicate can indicate that no more searching has to occur.
314 *
315 *
316 * @return true if the expression represents a stable number.
317 */
318 public boolean isStableNumber()
319 {
320 return true;
321 }
322
323 /**
324 * Get the analysis bits for this walker, as defined in the WalkerFactory.
325 * @return One of WalkerFactory#BIT_DESCENDANT, etc.
326 */
327 public int getAnalysisBits()
328 {
329
330 // J2SE does not support Xalan interpretive
331 /*
332 com.sun.org.apache.xalan.internal.templates.ElemVariable vvar = getElemVariable();
333 if(null != vvar)
334 {
335 XPath xpath = vvar.getSelect();
336 if(null != xpath)
337 {
338 Expression expr = xpath.getExpression();
339 if(null != expr && expr instanceof PathComponent)
340 {
341 return ((PathComponent)expr).getAnalysisBits();
342 }
343 }
344 }
345 */
346
347 return WalkerFactory.BIT_FILTER;
348 }
349
350
351 /**
352 * @see com.sun.org.apache.xpath.internal.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
353 */
354 public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
355 {
356 visitor.visitVariableRef(owner, this);
357 }
358 /**
359 * @see Expression#deepEquals(Expression)
360 */
361 public boolean deepEquals(Expression expr)
362 {
363 if(!isSameClass(expr))
364 return false;
365
366 if(!m_qname.equals(((Variable)expr).m_qname))
367 return false;
368
369 // J2SE does not support Xalan interpretive
370 /*
371 // We have to make sure that the qname really references
372 // the same variable element.
373 if(getElemVariable() != ((Variable)expr).getElemVariable())
374 return false;
375 */
376
377 return true;
378 }
379
380 static final java.lang.String PSUEDOVARNAMESPACE = "http://xml.apache.org/xalan/psuedovar";
381
382 /**
383 * Tell if this is a psuedo variable reference, declared by Xalan instead
384 * of by the user.
385 */
386 public boolean isPsuedoVarRef()
387 {
388 java.lang.String ns = m_qname.getNamespaceURI();
389 if((null != ns) && ns.equals(PSUEDOVARNAMESPACE))
390 {
391 if(m_qname.getLocalName().startsWith("#"))
392 return true;
393 }
394 return false;
395 }
396
397
398 }