PostgreSQL Source Code: contrib/xml2/xpath.c Source File

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xpath.c
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1/*
2 * contrib/xml2/xpath.c
3 *
4 * Parser interface for DOM-based parser (libxml) rather than
5 * stream-based SAX-type parser
6 */
7#include "postgres.h"
8
9#include "access/htup_details.h"
10#include "executor/spi.h"
11#include "fmgr.h"
12#include "funcapi.h"
13#include "lib/stringinfo.h"
14#include "utils/builtins.h"
15#include "utils/xml.h"
16
17/* libxml includes */
18
19#include <libxml/xpath.h>
20#include <libxml/tree.h>
21#include <libxml/xmlmemory.h>
22#include <libxml/xmlerror.h>
23#include <libxml/parserInternals.h>
24
25 PG_MODULE_MAGIC_EXT(
26 .name = "xml2",
27 .version = PG_VERSION
28);
29
30/* exported for use by xslt_proc.c */
31
32PgXmlErrorContext *pgxml_parser_init(PgXmlStrictness strictness);
33
34/* workspace for pgxml_xpath() */
35
36 typedef struct
37{
38 xmlDocPtr doctree;
39 xmlXPathContextPtr ctxt;
40 xmlXPathObjectPtr res;
41} xpath_workspace;
42
43/* local declarations */
44
45static xmlChar *pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
46 xmlChar *toptagname, xmlChar *septagname,
47 xmlChar *plainsep);
48
49static text *pgxml_result_to_text(xmlXPathObjectPtr res, xmlChar *toptag,
50 xmlChar *septag, xmlChar *plainsep);
51
52static xmlChar *pgxml_texttoxmlchar(text *textstring);
53
54static xpath_workspace *pgxml_xpath(text *document, xmlChar *xpath,
55 PgXmlErrorContext *xmlerrcxt);
56
57static void cleanup_workspace(xpath_workspace *workspace);
58
59
60/*
61 * Initialize for xml parsing.
62 *
63 * As with the underlying pg_xml_init function, calls to this MUST be followed
64 * by a PG_TRY block that guarantees that pg_xml_done is called.
65 */
66PgXmlErrorContext *
67 pgxml_parser_init(PgXmlStrictness strictness)
68{
69 PgXmlErrorContext *xmlerrcxt;
70
71 /* Set up error handling (we share the core's error handler) */
72 xmlerrcxt = pg_xml_init(strictness);
73
74 /* Note: we're assuming an elog cannot be thrown by the following calls */
75
76 /* Initialize libxml */
77 xmlInitParser();
78
79 return xmlerrcxt;
80}
81
82
83/* Encodes special characters (<, >, &, " and \r) as XML entities */
84
85 PG_FUNCTION_INFO_V1(xml_encode_special_chars);
86
87Datum
88 xml_encode_special_chars(PG_FUNCTION_ARGS)
89{
90 text *tin = PG_GETARG_TEXT_PP(0);
91 text *volatile tout = NULL;
92 xmlChar *volatile tt = NULL;
93 PgXmlErrorContext *xmlerrcxt;
94
95 xmlerrcxt = pg_xml_init(PG_XML_STRICTNESS_ALL);
96
97 PG_TRY();
98 {
99 xmlChar *ts;
100
101 ts = pgxml_texttoxmlchar(tin);
102
103 tt = xmlEncodeSpecialChars(NULL, ts);
104 if (tt == NULL || pg_xml_error_occurred(xmlerrcxt))
105 xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
106 "could not allocate xmlChar");
107 pfree(ts);
108
109 tout = cstring_to_text((char *) tt);
110 }
111 PG_CATCH();
112 {
113 if (tt != NULL)
114 xmlFree(tt);
115
116 pg_xml_done(xmlerrcxt, true);
117
118 PG_RE_THROW();
119 }
120 PG_END_TRY();
121
122 if (tt != NULL)
123 xmlFree(tt);
124
125 pg_xml_done(xmlerrcxt, false);
126
127 PG_RETURN_TEXT_P(tout);
128}
129
130/*
131 * Function translates a nodeset into a text representation
132 *
133 * iterates over each node in the set and calls xmlNodeDump to write it to
134 * an xmlBuffer -from which an xmlChar * string is returned.
135 *
136 * each representation is surrounded by <tagname> ... </tagname>
137 *
138 * plainsep is an ordinary (not tag) separator - if used, then nodes are
139 * cast to string as output method
140 */
141static xmlChar *
142 pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
143 xmlChar *toptagname,
144 xmlChar *septagname,
145 xmlChar *plainsep)
146{
147 volatile xmlBufferPtr buf = NULL;
148 xmlChar *volatile result = NULL;
149 PgXmlErrorContext *xmlerrcxt;
150
151 /* spin up some error handling */
152 xmlerrcxt = pg_xml_init(PG_XML_STRICTNESS_ALL);
153
154 PG_TRY();
155 {
156 buf = xmlBufferCreate();
157
158 if (buf == NULL || pg_xml_error_occurred(xmlerrcxt))
159 xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
160 "could not allocate xmlBuffer");
161
162 if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
163 {
164 xmlBufferWriteChar(buf, "<");
165 xmlBufferWriteCHAR(buf, toptagname);
166 xmlBufferWriteChar(buf, ">");
167 }
168 if (nodeset != NULL)
169 {
170 for (int i = 0; i < nodeset->nodeNr; i++)
171 {
172 if (plainsep != NULL)
173 {
174 xmlBufferWriteCHAR(buf,
175 xmlXPathCastNodeToString(nodeset->nodeTab[i]));
176
177 /* If this isn't the last entry, write the plain sep. */
178 if (i < (nodeset->nodeNr) - 1)
179 xmlBufferWriteChar(buf, (char *) plainsep);
180 }
181 else
182 {
183 if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
184 {
185 xmlBufferWriteChar(buf, "<");
186 xmlBufferWriteCHAR(buf, septagname);
187 xmlBufferWriteChar(buf, ">");
188 }
189 xmlNodeDump(buf,
190 nodeset->nodeTab[i]->doc,
191 nodeset->nodeTab[i],
192 1, 0);
193
194 if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
195 {
196 xmlBufferWriteChar(buf, "</");
197 xmlBufferWriteCHAR(buf, septagname);
198 xmlBufferWriteChar(buf, ">");
199 }
200 }
201 }
202 }
203
204 if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
205 {
206 xmlBufferWriteChar(buf, "</");
207 xmlBufferWriteCHAR(buf, toptagname);
208 xmlBufferWriteChar(buf, ">");
209 }
210
211 result = xmlStrdup(xmlBufferContent(buf));
212 if (result == NULL || pg_xml_error_occurred(xmlerrcxt))
213 xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
214 "could not allocate result");
215 }
216 PG_CATCH();
217 {
218 if (buf)
219 xmlBufferFree(buf);
220
221 pg_xml_done(xmlerrcxt, true);
222
223 PG_RE_THROW();
224 }
225 PG_END_TRY();
226
227 xmlBufferFree(buf);
228 pg_xml_done(xmlerrcxt, false);
229
230 return result;
231}
232
233
234/* Translate a PostgreSQL "varlena" -i.e. a variable length parameter
235 * into the libxml2 representation
236 */
237static xmlChar *
238 pgxml_texttoxmlchar(text *textstring)
239{
240 return (xmlChar *) text_to_cstring(textstring);
241}
242
243/* Publicly visible XPath functions */
244
245/*
246 * This is a "raw" xpath function. Check that it returns child elements
247 * properly
248 */
249 PG_FUNCTION_INFO_V1(xpath_nodeset);
250
251Datum
252 xpath_nodeset(PG_FUNCTION_ARGS)
253{
254 text *document = PG_GETARG_TEXT_PP(0);
255 text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
256 xmlChar *toptag = pgxml_texttoxmlchar(PG_GETARG_TEXT_PP(2));
257 xmlChar *septag = pgxml_texttoxmlchar(PG_GETARG_TEXT_PP(3));
258 xmlChar *xpath;
259 text *volatile xpres = NULL;
260 xpath_workspace *volatile workspace = NULL;
261 PgXmlErrorContext *xmlerrcxt;
262
263 xpath = pgxml_texttoxmlchar(xpathsupp);
264 xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
265
266 PG_TRY();
267 {
268 workspace = pgxml_xpath(document, xpath, xmlerrcxt);
269 xpres = pgxml_result_to_text(workspace->res, toptag, septag, NULL);
270 }
271 PG_CATCH();
272 {
273 if (workspace)
274 cleanup_workspace(workspace);
275
276 pg_xml_done(xmlerrcxt, true);
277 PG_RE_THROW();
278 }
279 PG_END_TRY();
280
281 cleanup_workspace(workspace);
282 pg_xml_done(xmlerrcxt, false);
283
284 pfree(xpath);
285
286 if (xpres == NULL)
287 PG_RETURN_NULL();
288 PG_RETURN_TEXT_P(xpres);
289}
290
291/*
292 * The following function is almost identical, but returns the elements in
293 * a list.
294 */
295 PG_FUNCTION_INFO_V1(xpath_list);
296
297Datum
298 xpath_list(PG_FUNCTION_ARGS)
299{
300 text *document = PG_GETARG_TEXT_PP(0);
301 text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
302 xmlChar *plainsep = pgxml_texttoxmlchar(PG_GETARG_TEXT_PP(2));
303 xmlChar *xpath;
304 text *volatile xpres = NULL;
305 xpath_workspace *volatile workspace = NULL;
306 PgXmlErrorContext *xmlerrcxt;
307
308 xpath = pgxml_texttoxmlchar(xpathsupp);
309 xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
310
311 PG_TRY();
312 {
313 workspace = pgxml_xpath(document, xpath, xmlerrcxt);
314 xpres = pgxml_result_to_text(workspace->res, NULL, NULL, plainsep);
315 }
316 PG_CATCH();
317 {
318 if (workspace)
319 cleanup_workspace(workspace);
320
321 pg_xml_done(xmlerrcxt, true);
322 PG_RE_THROW();
323 }
324 PG_END_TRY();
325
326 cleanup_workspace(workspace);
327 pg_xml_done(xmlerrcxt, false);
328
329 pfree(xpath);
330
331 if (xpres == NULL)
332 PG_RETURN_NULL();
333 PG_RETURN_TEXT_P(xpres);
334}
335
336
337 PG_FUNCTION_INFO_V1(xpath_string);
338
339Datum
340 xpath_string(PG_FUNCTION_ARGS)
341{
342 text *document = PG_GETARG_TEXT_PP(0);
343 text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
344 xmlChar *xpath;
345 int32 pathsize;
346 text *volatile xpres = NULL;
347 xpath_workspace *volatile workspace = NULL;
348 PgXmlErrorContext *xmlerrcxt;
349
350 pathsize = VARSIZE_ANY_EXHDR(xpathsupp);
351
352 /*
353 * We encapsulate the supplied path with "string()" = 8 chars + 1 for NUL
354 * at end
355 */
356 /* We could try casting to string using the libxml function? */
357
358 xpath = (xmlChar *) palloc(pathsize + 9);
359 memcpy(xpath, "string(", 7);
360 memcpy(xpath + 7, VARDATA_ANY(xpathsupp), pathsize);
361 xpath[pathsize + 7] = ')';
362 xpath[pathsize + 8] = '0円';
363
364 xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
365
366 PG_TRY();
367 {
368 workspace = pgxml_xpath(document, xpath, xmlerrcxt);
369 xpres = pgxml_result_to_text(workspace->res, NULL, NULL, NULL);
370 }
371 PG_CATCH();
372 {
373 if (workspace)
374 cleanup_workspace(workspace);
375
376 pg_xml_done(xmlerrcxt, true);
377 PG_RE_THROW();
378 }
379 PG_END_TRY();
380
381 cleanup_workspace(workspace);
382 pg_xml_done(xmlerrcxt, false);
383
384 pfree(xpath);
385
386 if (xpres == NULL)
387 PG_RETURN_NULL();
388 PG_RETURN_TEXT_P(xpres);
389}
390
391
392 PG_FUNCTION_INFO_V1(xpath_number);
393
394Datum
395 xpath_number(PG_FUNCTION_ARGS)
396{
397 text *document = PG_GETARG_TEXT_PP(0);
398 text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
399 xmlChar *xpath;
400 volatile float4 fRes = 0.0;
401 volatile bool isNull = false;
402 xpath_workspace *volatile workspace = NULL;
403 PgXmlErrorContext *xmlerrcxt;
404
405 xpath = pgxml_texttoxmlchar(xpathsupp);
406 xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
407
408 PG_TRY();
409 {
410 workspace = pgxml_xpath(document, xpath, xmlerrcxt);
411 pfree(xpath);
412
413 if (workspace->res == NULL)
414 isNull = true;
415 else
416 fRes = xmlXPathCastToNumber(workspace->res);
417 }
418 PG_CATCH();
419 {
420 if (workspace)
421 cleanup_workspace(workspace);
422
423 pg_xml_done(xmlerrcxt, true);
424 PG_RE_THROW();
425 }
426 PG_END_TRY();
427
428 cleanup_workspace(workspace);
429 pg_xml_done(xmlerrcxt, false);
430
431 if (isNull || xmlXPathIsNaN(fRes))
432 PG_RETURN_NULL();
433
434 PG_RETURN_FLOAT4(fRes);
435}
436
437
438 PG_FUNCTION_INFO_V1(xpath_bool);
439
440Datum
441 xpath_bool(PG_FUNCTION_ARGS)
442{
443 text *document = PG_GETARG_TEXT_PP(0);
444 text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
445 xmlChar *xpath;
446 volatile int bRes = 0;
447 xpath_workspace *volatile workspace = NULL;
448 PgXmlErrorContext *xmlerrcxt;
449
450 xpath = pgxml_texttoxmlchar(xpathsupp);
451 xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
452
453 PG_TRY();
454 {
455 workspace = pgxml_xpath(document, xpath, xmlerrcxt);
456 pfree(xpath);
457
458 if (workspace->res == NULL)
459 bRes = 0;
460 else
461 bRes = xmlXPathCastToBoolean(workspace->res);
462 }
463 PG_CATCH();
464 {
465 if (workspace)
466 cleanup_workspace(workspace);
467
468 pg_xml_done(xmlerrcxt, true);
469 PG_RE_THROW();
470 }
471 PG_END_TRY();
472
473 cleanup_workspace(workspace);
474 pg_xml_done(xmlerrcxt, false);
475
476 PG_RETURN_BOOL(bRes);
477}
478
479
480
481/* Core function to evaluate XPath query */
482
483static xpath_workspace *
484 pgxml_xpath(text *document, xmlChar *xpath, PgXmlErrorContext *xmlerrcxt)
485{
486 int32 docsize = VARSIZE_ANY_EXHDR(document);
487 xmlXPathCompExprPtr comppath;
488 xpath_workspace *workspace = (xpath_workspace *)
489 palloc0(sizeof(xpath_workspace));
490
491 workspace->doctree = NULL;
492 workspace->ctxt = NULL;
493 workspace->res = NULL;
494
495 workspace->doctree = xmlReadMemory((char *) VARDATA_ANY(document),
496 docsize, NULL, NULL,
497 XML_PARSE_NOENT);
498 if (workspace->doctree != NULL)
499 {
500 workspace->ctxt = xmlXPathNewContext(workspace->doctree);
501 workspace->ctxt->node = xmlDocGetRootElement(workspace->doctree);
502
503 /* compile the path */
504 comppath = xmlXPathCtxtCompile(workspace->ctxt, xpath);
505 if (comppath == NULL || pg_xml_error_occurred(xmlerrcxt))
506 xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
507 "XPath Syntax Error");
508
509 /* Now evaluate the path expression. */
510 workspace->res = xmlXPathCompiledEval(comppath, workspace->ctxt);
511
512 xmlXPathFreeCompExpr(comppath);
513 }
514
515 return workspace;
516}
517
518/* Clean up after processing the result of pgxml_xpath() */
519static void
520 cleanup_workspace(xpath_workspace *workspace)
521{
522 if (workspace->res)
523 xmlXPathFreeObject(workspace->res);
524 workspace->res = NULL;
525 if (workspace->ctxt)
526 xmlXPathFreeContext(workspace->ctxt);
527 workspace->ctxt = NULL;
528 if (workspace->doctree)
529 xmlFreeDoc(workspace->doctree);
530 workspace->doctree = NULL;
531}
532
533static text *
534 pgxml_result_to_text(xmlXPathObjectPtr res,
535 xmlChar *toptag,
536 xmlChar *septag,
537 xmlChar *plainsep)
538{
539 xmlChar *volatile xpresstr = NULL;
540 text *volatile xpres = NULL;
541 PgXmlErrorContext *xmlerrcxt;
542
543 if (res == NULL)
544 return NULL;
545
546 /* spin some error handling */
547 xmlerrcxt = pg_xml_init(PG_XML_STRICTNESS_ALL);
548
549 PG_TRY();
550 {
551 switch (res->type)
552 {
553 case XPATH_NODESET:
554 xpresstr = pgxmlNodeSetToText(res->nodesetval,
555 toptag,
556 septag, plainsep);
557 break;
558
559 case XPATH_STRING:
560 xpresstr = xmlStrdup(res->stringval);
561 if (xpresstr == NULL || pg_xml_error_occurred(xmlerrcxt))
562 xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
563 "could not allocate result");
564 break;
565
566 default:
567 elog(NOTICE, "unsupported XQuery result: %d", res->type);
568 xpresstr = xmlStrdup((const xmlChar *) "<unsupported/>");
569 if (xpresstr == NULL || pg_xml_error_occurred(xmlerrcxt))
570 xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
571 "could not allocate result");
572 }
573
574 /* Now convert this result back to text */
575 xpres = cstring_to_text((char *) xpresstr);
576 }
577 PG_CATCH();
578 {
579 if (xpresstr != NULL)
580 xmlFree(xpresstr);
581
582 pg_xml_done(xmlerrcxt, true);
583
584 PG_RE_THROW();
585 }
586 PG_END_TRY();
587
588 /* Free various storage */
589 xmlFree(xpresstr);
590
591 pg_xml_done(xmlerrcxt, false);
592
593 return xpres;
594}
595
596/*
597 * xpath_table is a table function. It needs some tidying (as do the
598 * other functions here!
599 */
600 PG_FUNCTION_INFO_V1(xpath_table);
601
602Datum
603 xpath_table(PG_FUNCTION_ARGS)
604{
605 /* Function parameters */
606 char *pkeyfield = text_to_cstring(PG_GETARG_TEXT_PP(0));
607 char *xmlfield = text_to_cstring(PG_GETARG_TEXT_PP(1));
608 char *relname = text_to_cstring(PG_GETARG_TEXT_PP(2));
609 char *xpathset = text_to_cstring(PG_GETARG_TEXT_PP(3));
610 char *condition = text_to_cstring(PG_GETARG_TEXT_PP(4));
611
612 /* SPI (input tuple) support */
613 SPITupleTable *tuptable;
614 HeapTuple spi_tuple;
615 TupleDesc spi_tupdesc;
616
617
618 ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
619 AttInMetadata *attinmeta;
620
621 char **values;
622 xmlChar **xpaths;
623 char *pos;
624 const char *pathsep = "|";
625
626 int numpaths;
627 int ret;
628 uint64 proc;
629 int j;
630 int rownr; /* For issuing multiple rows from one original
631 * document */
632 bool had_values; /* To determine end of nodeset results */
633 StringInfoData query_buf;
634 PgXmlErrorContext *xmlerrcxt;
635 volatile xmlDocPtr doctree = NULL;
636
637 InitMaterializedSRF(fcinfo, MAT_SRF_USE_EXPECTED_DESC);
638
639 /* must have at least one output column (for the pkey) */
640 if (rsinfo->setDesc->natts < 1)
641 ereport(ERROR,
642 (errcode(ERRCODE_SYNTAX_ERROR),
643 errmsg("xpath_table must have at least one output column")));
644
645 /*
646 * At the moment we assume that the returned attributes make sense for the
647 * XPath specified (i.e. we trust the caller). It's not fatal if they get
648 * it wrong - the input function for the column type will raise an error
649 * if the path result can't be converted into the correct binary
650 * representation.
651 */
652
653 attinmeta = TupleDescGetAttInMetadata(rsinfo->setDesc);
654
655 values = (char **) palloc(rsinfo->setDesc->natts * sizeof(char *));
656 xpaths = (xmlChar **) palloc(rsinfo->setDesc->natts * sizeof(xmlChar *));
657
658 /*
659 * Split XPaths. xpathset is a writable CString.
660 *
661 * Note that we stop splitting once we've done all needed for tupdesc
662 */
663 numpaths = 0;
664 pos = xpathset;
665 while (numpaths < (rsinfo->setDesc->natts - 1))
666 {
667 xpaths[numpaths++] = (xmlChar *) pos;
668 pos = strstr(pos, pathsep);
669 if (pos != NULL)
670 {
671 *pos = '0円';
672 pos++;
673 }
674 else
675 break;
676 }
677
678 /* Now build query */
679 initStringInfo(&query_buf);
680
681 /* Build initial sql statement */
682 appendStringInfo(&query_buf, "SELECT %s, %s FROM %s WHERE %s",
683 pkeyfield,
684 xmlfield,
685 relname,
686 condition);
687
688 SPI_connect();
689
690 if ((ret = SPI_exec(query_buf.data, 0)) != SPI_OK_SELECT)
691 elog(ERROR, "xpath_table: SPI execution failed for query %s",
692 query_buf.data);
693
694 proc = SPI_processed;
695 tuptable = SPI_tuptable;
696 spi_tupdesc = tuptable->tupdesc;
697
698 /*
699 * Check that SPI returned correct result. If you put a comma into one of
700 * the function parameters, this will catch it when the SPI query returns
701 * e.g. 3 columns.
702 */
703 if (spi_tupdesc->natts != 2)
704 {
705 ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
706 errmsg("expression returning multiple columns is not valid in parameter list"),
707 errdetail("Expected two columns in SPI result, got %d.", spi_tupdesc->natts)));
708 }
709
710 /*
711 * Setup the parser. This should happen after we are done evaluating the
712 * query, in case it calls functions that set up libxml differently.
713 */
714 xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
715
716 PG_TRY();
717 {
718 /* For each row i.e. document returned from SPI */
719 uint64 i;
720
721 for (i = 0; i < proc; i++)
722 {
723 char *pkey;
724 char *xmldoc;
725 xmlXPathContextPtr ctxt;
726 xmlXPathObjectPtr res;
727 xmlChar *resstr;
728 xmlXPathCompExprPtr comppath;
729 HeapTuple ret_tuple;
730
731 /* Extract the row data as C Strings */
732 spi_tuple = tuptable->vals[i];
733 pkey = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
734 xmldoc = SPI_getvalue(spi_tuple, spi_tupdesc, 2);
735
736 /*
737 * Clear the values array, so that not-well-formed documents
738 * return NULL in all columns. Note that this also means that
739 * spare columns will be NULL.
740 */
741 for (j = 0; j < rsinfo->setDesc->natts; j++)
742 values[j] = NULL;
743
744 /* Insert primary key */
745 values[0] = pkey;
746
747 /* Parse the document */
748 if (xmldoc)
749 doctree = xmlReadMemory(xmldoc, strlen(xmldoc),
750 NULL, NULL,
751 XML_PARSE_NOENT);
752 else /* treat NULL as not well-formed */
753 doctree = NULL;
754
755 if (doctree == NULL)
756 {
757 /* not well-formed, so output all-NULL tuple */
758 ret_tuple = BuildTupleFromCStrings(attinmeta, values);
759 tuplestore_puttuple(rsinfo->setResult, ret_tuple);
760 heap_freetuple(ret_tuple);
761 }
762 else
763 {
764 /* New loop here - we have to deal with nodeset results */
765 rownr = 0;
766
767 do
768 {
769 /* Now evaluate the set of xpaths. */
770 had_values = false;
771 for (j = 0; j < numpaths; j++)
772 {
773 ctxt = xmlXPathNewContext(doctree);
774 if (ctxt == NULL || pg_xml_error_occurred(xmlerrcxt))
775 xml_ereport(xmlerrcxt,
776 ERROR, ERRCODE_OUT_OF_MEMORY,
777 "could not allocate XPath context");
778
779 ctxt->node = xmlDocGetRootElement(doctree);
780
781 /* compile the path */
782 comppath = xmlXPathCtxtCompile(ctxt, xpaths[j]);
783 if (comppath == NULL || pg_xml_error_occurred(xmlerrcxt))
784 xml_ereport(xmlerrcxt, ERROR,
785 ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
786 "XPath Syntax Error");
787
788 /* Now evaluate the path expression. */
789 res = xmlXPathCompiledEval(comppath, ctxt);
790 xmlXPathFreeCompExpr(comppath);
791
792 if (res != NULL)
793 {
794 switch (res->type)
795 {
796 case XPATH_NODESET:
797 /* We see if this nodeset has enough nodes */
798 if (res->nodesetval != NULL &&
799 rownr < res->nodesetval->nodeNr)
800 {
801 resstr = xmlXPathCastNodeToString(res->nodesetval->nodeTab[rownr]);
802 if (resstr == NULL || pg_xml_error_occurred(xmlerrcxt))
803 xml_ereport(xmlerrcxt,
804 ERROR, ERRCODE_OUT_OF_MEMORY,
805 "could not allocate result");
806 had_values = true;
807 }
808 else
809 resstr = NULL;
810
811 break;
812
813 case XPATH_STRING:
814 resstr = xmlStrdup(res->stringval);
815 if (resstr == NULL || pg_xml_error_occurred(xmlerrcxt))
816 xml_ereport(xmlerrcxt,
817 ERROR, ERRCODE_OUT_OF_MEMORY,
818 "could not allocate result");
819 break;
820
821 default:
822 elog(NOTICE, "unsupported XQuery result: %d", res->type);
823 resstr = xmlStrdup((const xmlChar *) "<unsupported/>");
824 if (resstr == NULL || pg_xml_error_occurred(xmlerrcxt))
825 xml_ereport(xmlerrcxt,
826 ERROR, ERRCODE_OUT_OF_MEMORY,
827 "could not allocate result");
828 }
829
830 /*
831 * Insert this into the appropriate column in the
832 * result tuple.
833 */
834 values[j + 1] = (char *) resstr;
835 }
836 xmlXPathFreeContext(ctxt);
837 }
838
839 /* Now add the tuple to the output, if there is one. */
840 if (had_values)
841 {
842 ret_tuple = BuildTupleFromCStrings(attinmeta, values);
843 tuplestore_puttuple(rsinfo->setResult, ret_tuple);
844 heap_freetuple(ret_tuple);
845 }
846
847 rownr++;
848 } while (had_values);
849 }
850
851 if (doctree != NULL)
852 xmlFreeDoc(doctree);
853 doctree = NULL;
854
855 if (pkey)
856 pfree(pkey);
857 if (xmldoc)
858 pfree(xmldoc);
859 }
860 }
861 PG_CATCH();
862 {
863 if (doctree != NULL)
864 xmlFreeDoc(doctree);
865
866 pg_xml_done(xmlerrcxt, true);
867
868 PG_RE_THROW();
869 }
870 PG_END_TRY();
871
872 if (doctree != NULL)
873 xmlFreeDoc(doctree);
874
875 pg_xml_done(xmlerrcxt, false);
876
877 SPI_finish();
878
879 /*
880 * SFRM_Materialize mode expects us to return a NULL Datum. The actual
881 * tuples are in our tuplestore and passed back through rsinfo->setResult.
882 * rsinfo->setDesc is set to the tuple description that we actually used
883 * to build our tuples with, so the caller can verify we did what it was
884 * expecting.
885 */
886 return (Datum) 0;
887}
static Datum values[MAXATTR]
Definition: bootstrap.c:153
int32_t int32
Definition: c.h:534
uint64_t uint64
Definition: c.h:539
float float4
Definition: c.h:634
int errdetail(const char *fmt,...)
Definition: elog.c:1207
int errcode(int sqlerrcode)
Definition: elog.c:854
int errmsg(const char *fmt,...)
Definition: elog.c:1071
#define PG_RE_THROW()
Definition: elog.h:405
#define PG_TRY(...)
Definition: elog.h:372
#define PG_END_TRY(...)
Definition: elog.h:397
#define ERROR
Definition: elog.h:39
#define PG_CATCH(...)
Definition: elog.h:382
#define elog(elevel,...)
Definition: elog.h:226
#define NOTICE
Definition: elog.h:35
#define ereport(elevel,...)
Definition: elog.h:150
HeapTuple BuildTupleFromCStrings(AttInMetadata *attinmeta, char **values)
Definition: execTuples.c:2324
AttInMetadata * TupleDescGetAttInMetadata(TupleDesc tupdesc)
Definition: execTuples.c:2275
#define PG_GETARG_TEXT_PP(n)
Definition: fmgr.h:309
#define PG_RETURN_NULL()
Definition: fmgr.h:345
#define PG_RETURN_TEXT_P(x)
Definition: fmgr.h:372
#define PG_RETURN_FLOAT4(x)
Definition: fmgr.h:366
#define PG_FUNCTION_ARGS
Definition: fmgr.h:193
#define PG_RETURN_BOOL(x)
Definition: fmgr.h:359
void InitMaterializedSRF(FunctionCallInfo fcinfo, bits32 flags)
Definition: funcapi.c:76
#define MAT_SRF_USE_EXPECTED_DESC
Definition: funcapi.h:296
void heap_freetuple(HeapTuple htup)
Definition: heaptuple.c:1435
j
int j
Definition: isn.c:78
i
int i
Definition: isn.c:77
void pfree(void *pointer)
Definition: mcxt.c:1594
void * palloc0(Size size)
Definition: mcxt.c:1395
void * palloc(Size size)
Definition: mcxt.c:1365
NameData relname
Definition: pg_class.h:38
static char * buf
Definition: pg_test_fsync.c:72
uint64_t Datum
Definition: postgres.h:70
uint64 SPI_processed
Definition: spi.c:44
SPITupleTable * SPI_tuptable
Definition: spi.c:45
int SPI_connect(void)
Definition: spi.c:94
int SPI_finish(void)
Definition: spi.c:182
int SPI_exec(const char *src, long tcount)
Definition: spi.c:630
char * SPI_getvalue(HeapTuple tuple, TupleDesc tupdesc, int fnumber)
Definition: spi.c:1220
#define SPI_OK_SELECT
Definition: spi.h:86
void appendStringInfo(StringInfo str, const char *fmt,...)
Definition: stringinfo.c:145
void initStringInfo(StringInfo str)
Definition: stringinfo.c:97
TupleDesc setDesc
Definition: execnodes.h:364
Tuplestorestate * setResult
Definition: execnodes.h:363
Definition: spi.h:23
TupleDesc tupdesc
Definition: spi.h:25
HeapTuple * vals
Definition: spi.h:26
int natts
Definition: tupdesc.h:137
Definition: c.h:692
Definition: xpath.c:37
xmlXPathContextPtr ctxt
Definition: xpath.c:39
xmlDocPtr doctree
Definition: xpath.c:38
xmlXPathObjectPtr res
Definition: xpath.c:40
void tuplestore_puttuple(Tuplestorestate *state, HeapTuple tuple)
Definition: tuplestore.c:764
static Size VARSIZE_ANY_EXHDR(const void *PTR)
Definition: varatt.h:472
static char * VARDATA_ANY(const void *PTR)
Definition: varatt.h:486
text * cstring_to_text(const char *s)
Definition: varlena.c:181
char * text_to_cstring(const text *t)
Definition: varlena.c:214
const char * name
Datum xpath(PG_FUNCTION_ARGS)
Definition: xml.c:4566
struct PgXmlErrorContext PgXmlErrorContext
Definition: xml.h:48
PgXmlErrorContext * pg_xml_init(PgXmlStrictness strictness)
void xml_ereport(PgXmlErrorContext *errcxt, int level, int sqlcode, const char *msg)
bool pg_xml_error_occurred(PgXmlErrorContext *errcxt)
void pg_xml_done(PgXmlErrorContext *errcxt, bool isError)
PgXmlStrictness
Definition: xml.h:40
@ PG_XML_STRICTNESS_LEGACY
Definition: xml.h:41
@ PG_XML_STRICTNESS_ALL
Definition: xml.h:44
static text * pgxml_result_to_text(xmlXPathObjectPtr res, xmlChar *toptag, xmlChar *septag, xmlChar *plainsep)
Definition: xpath.c:534
Datum xpath_bool(PG_FUNCTION_ARGS)
Definition: xpath.c:441
Datum xpath_number(PG_FUNCTION_ARGS)
Definition: xpath.c:395
Datum xpath_table(PG_FUNCTION_ARGS)
Definition: xpath.c:603
static xmlChar * pgxml_texttoxmlchar(text *textstring)
Definition: xpath.c:238
PgXmlErrorContext * pgxml_parser_init(PgXmlStrictness strictness)
Definition: xpath.c:67
Datum xpath_string(PG_FUNCTION_ARGS)
Definition: xpath.c:340
static void cleanup_workspace(xpath_workspace *workspace)
Definition: xpath.c:520
Datum xml_encode_special_chars(PG_FUNCTION_ARGS)
Definition: xpath.c:88
Datum xpath_list(PG_FUNCTION_ARGS)
Definition: xpath.c:298
static xmlChar * pgxmlNodeSetToText(xmlNodeSetPtr nodeset, xmlChar *toptagname, xmlChar *septagname, xmlChar *plainsep)
Definition: xpath.c:142
static xpath_workspace * pgxml_xpath(text *document, xmlChar *xpath, PgXmlErrorContext *xmlerrcxt)
Definition: xpath.c:484
PG_MODULE_MAGIC_EXT(.name="xml2",.version=PG_VERSION)
Datum xpath_nodeset(PG_FUNCTION_ARGS)
Definition: xpath.c:252
PG_FUNCTION_INFO_V1(xml_encode_special_chars)

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