mirror of
https://github.com/postgres/postgres.git
synced 2025-07-27 12:41:57 +03:00
Move new version of contrib/ xml into xml2, keep old version in /xml.
This commit is contained in:
Bruce Momjian
893
contrib/xml2/xpath.c
Normal file
893
contrib/xml2/xpath.c
Normal file
@ -0,0 +1,893 @@
|
||||
/* Parser interface for DOM-based parser (libxml) rather than
|
||||
stream-based SAX-type parser */
|
||||
|
||||
#include "postgres.h"
|
||||
#include "fmgr.h"
|
||||
#include "executor/spi.h"
|
||||
#include "funcapi.h"
|
||||
#include "miscadmin.h"
|
||||
#include "lib/stringinfo.h"
|
||||
|
||||
/* libxml includes */
|
||||
|
||||
#include <libxml/xpath.h>
|
||||
#include <libxml/tree.h>
|
||||
#include <libxml/xmlmemory.h>
|
||||
#include <libxml/xmlerror.h>
|
||||
#include <libxml/parserInternals.h>
|
||||
|
||||
/* declarations */
|
||||
|
||||
static void *pgxml_palloc(size_t size);
|
||||
static void *pgxml_repalloc(void *ptr, size_t size);
|
||||
static void pgxml_pfree(void *ptr);
|
||||
static char *pgxml_pstrdup(const char *string);
|
||||
static void pgxml_errorHandler (void * ctxt, const char *msg, ...);
|
||||
|
||||
void elog_error(int level, char *explain, int force);
|
||||
void pgxml_parser_init(void);
|
||||
|
||||
static xmlChar *pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
|
||||
xmlChar * toptagname, xmlChar * septagname,
|
||||
xmlChar * plainsep);
|
||||
|
||||
text *pgxml_result_to_text(xmlXPathObjectPtr res, xmlChar *toptag,
|
||||
xmlChar *septag, xmlChar *plainsep);
|
||||
|
||||
xmlChar *pgxml_texttoxmlchar(text *textstring);
|
||||
|
||||
static xmlXPathObjectPtr pgxml_xpath(text *document, xmlChar* xpath);
|
||||
|
||||
|
||||
Datum pgxml_parse(PG_FUNCTION_ARGS);
|
||||
Datum xpath_nodeset(PG_FUNCTION_ARGS);
|
||||
Datum xpath_string(PG_FUNCTION_ARGS);
|
||||
Datum xpath_number(PG_FUNCTION_ARGS);
|
||||
Datum xpath_bool(PG_FUNCTION_ARGS);
|
||||
Datum xpath_list(PG_FUNCTION_ARGS);
|
||||
Datum xpath_table(PG_FUNCTION_ARGS);
|
||||
|
||||
/* Global variables */
|
||||
char *errbuf; /* per line error buffer */
|
||||
char *pgxml_errorMsg = NULL; /* overall error message */
|
||||
|
||||
/* Convenience macros */
|
||||
|
||||
#define GET_TEXT(cstrp) DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(cstrp)))
|
||||
#define GET_STR(textp) DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(textp)))
|
||||
|
||||
#define ERRBUF_SIZE 200
|
||||
|
||||
/* memory handling passthrough functions (e.g. palloc, pstrdup are
|
||||
currently macros, and the others might become so...) */
|
||||
|
||||
static void *
|
||||
pgxml_palloc(size_t size)
|
||||
{
|
||||
/* elog(DEBUG1,"Alloc %d in CMC %x",size,CurrentMemoryContext); */
|
||||
return palloc(size);
|
||||
}
|
||||
|
||||
static void *
|
||||
pgxml_repalloc(void *ptr, size_t size)
|
||||
{
|
||||
/* elog(DEBUG1,"ReAlloc in CMC %x",CurrentMemoryContext);*/
|
||||
return repalloc(ptr, size);
|
||||
}
|
||||
|
||||
static void
|
||||
pgxml_pfree(void *ptr)
|
||||
{
|
||||
/* elog(DEBUG1,"Free in CMC %x",CurrentMemoryContext); */
|
||||
return pfree(ptr);
|
||||
}
|
||||
|
||||
static char *
|
||||
pgxml_pstrdup(const char *string)
|
||||
{
|
||||
return pstrdup(string);
|
||||
}
|
||||
|
||||
/* The error handling function. This formats an error message and sets
|
||||
* a flag - an ereport will be issued prior to return
|
||||
*/
|
||||
|
||||
static void
|
||||
pgxml_errorHandler (void * ctxt, const char *msg, ...)
|
||||
{
|
||||
va_list args;
|
||||
|
||||
va_start(args, msg);
|
||||
vsnprintf(errbuf, ERRBUF_SIZE, msg, args);
|
||||
va_end(args);
|
||||
/* Now copy the argument across */
|
||||
if (pgxml_errorMsg == NULL)
|
||||
{
|
||||
pgxml_errorMsg = pstrdup(errbuf);
|
||||
}
|
||||
else
|
||||
{
|
||||
int32 xsize = strlen(pgxml_errorMsg);
|
||||
pgxml_errorMsg = repalloc(pgxml_errorMsg,
|
||||
(size_t) (xsize + strlen(errbuf) + 1));
|
||||
strncpy(&pgxml_errorMsg[xsize-1],errbuf,strlen(errbuf));
|
||||
pgxml_errorMsg[xsize+strlen(errbuf)-1]='\0';
|
||||
|
||||
}
|
||||
memset(errbuf,0,ERRBUF_SIZE);
|
||||
}
|
||||
|
||||
/* This function reports the current message at the level specified */
|
||||
void elog_error(int level, char *explain, int force)
|
||||
{
|
||||
if (force || (pgxml_errorMsg != NULL))
|
||||
{
|
||||
if (pgxml_errorMsg == NULL)
|
||||
{
|
||||
ereport(level,(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
|
||||
errmsg(explain)));
|
||||
}
|
||||
else
|
||||
{
|
||||
ereport(level,(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
|
||||
errmsg("%s:%s",explain,pgxml_errorMsg)));
|
||||
pfree(pgxml_errorMsg);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void
|
||||
pgxml_parser_init()
|
||||
{
|
||||
/*
|
||||
* This code could also set parser settings from user-supplied info.
|
||||
* Quite how these settings are made is another matter :)
|
||||
*/
|
||||
|
||||
xmlMemSetup(pgxml_pfree, pgxml_palloc, pgxml_repalloc, pgxml_pstrdup);
|
||||
xmlInitParser();
|
||||
|
||||
xmlSetGenericErrorFunc(NULL, pgxml_errorHandler);
|
||||
|
||||
xmlSubstituteEntitiesDefault(1);
|
||||
xmlLoadExtDtdDefaultValue = 1;
|
||||
|
||||
pgxml_errorMsg = NULL;
|
||||
|
||||
errbuf = palloc(200);
|
||||
memset(errbuf,0,200);
|
||||
|
||||
}
|
||||
|
||||
|
||||
/* Returns true if document is well-formed */
|
||||
|
||||
PG_FUNCTION_INFO_V1(pgxml_parse);
|
||||
|
||||
Datum
|
||||
pgxml_parse(PG_FUNCTION_ARGS)
|
||||
{
|
||||
/* called as pgxml_parse(document) */
|
||||
xmlDocPtr doctree;
|
||||
text *t = PG_GETARG_TEXT_P(0); /* document buffer */
|
||||
int32 docsize = VARSIZE(t) - VARHDRSZ;
|
||||
|
||||
pgxml_parser_init();
|
||||
|
||||
doctree = xmlParseMemory((char *) VARDATA(t), docsize);
|
||||
if (doctree == NULL)
|
||||
{
|
||||
xmlCleanupParser();
|
||||
PG_RETURN_BOOL(false); /* i.e. not well-formed */
|
||||
}
|
||||
xmlCleanupParser();
|
||||
xmlFreeDoc(doctree);
|
||||
PG_RETURN_BOOL(true);
|
||||
}
|
||||
|
||||
|
||||
static xmlChar
|
||||
*
|
||||
pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
|
||||
xmlChar * toptagname,
|
||||
xmlChar * septagname,
|
||||
xmlChar * plainsep)
|
||||
{
|
||||
/* Function translates a nodeset into a text representation */
|
||||
|
||||
/*
|
||||
* iterates over each node in the set and calls xmlNodeDump to write
|
||||
* it to an xmlBuffer -from which an xmlChar * string is returned.
|
||||
*/
|
||||
|
||||
/* each representation is surrounded by <tagname> ... </tagname> */
|
||||
/* plainsep is an ordinary (not tag) seperator - if used, then
|
||||
* nodes are cast to string as output method */
|
||||
|
||||
|
||||
xmlBufferPtr buf;
|
||||
xmlChar *result;
|
||||
int i;
|
||||
|
||||
buf = xmlBufferCreate();
|
||||
|
||||
if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
|
||||
{
|
||||
xmlBufferWriteChar(buf, "<");
|
||||
xmlBufferWriteCHAR(buf, toptagname);
|
||||
xmlBufferWriteChar(buf, ">");
|
||||
}
|
||||
if (nodeset != NULL)
|
||||
{
|
||||
for (i = 0; i < nodeset->nodeNr; i++)
|
||||
{
|
||||
|
||||
if (plainsep != NULL) {
|
||||
xmlBufferWriteCHAR(buf,
|
||||
xmlXPathCastNodeToString(nodeset->nodeTab[i]));
|
||||
|
||||
/* If this isn't the last entry, write the plain sep. */
|
||||
if (i < (nodeset->nodeNr)-1) {
|
||||
xmlBufferWriteChar(buf, plainsep);
|
||||
}
|
||||
} else {
|
||||
|
||||
|
||||
if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
|
||||
{
|
||||
xmlBufferWriteChar(buf, "<");
|
||||
xmlBufferWriteCHAR(buf, septagname);
|
||||
xmlBufferWriteChar(buf, ">");
|
||||
}
|
||||
xmlNodeDump(buf,
|
||||
nodeset->nodeTab[i]->doc,
|
||||
nodeset->nodeTab[i],
|
||||
1, 0);
|
||||
|
||||
if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
|
||||
{
|
||||
xmlBufferWriteChar(buf, "</");
|
||||
xmlBufferWriteCHAR(buf, septagname);
|
||||
xmlBufferWriteChar(buf, ">");
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
|
||||
{
|
||||
xmlBufferWriteChar(buf, "</");
|
||||
xmlBufferWriteCHAR(buf, toptagname);
|
||||
xmlBufferWriteChar(buf, ">");
|
||||
}
|
||||
result = xmlStrdup(buf->content);
|
||||
xmlBufferFree(buf);
|
||||
return result;
|
||||
}
|
||||
|
||||
|
||||
/* Translate a PostgreSQL "varlena" -i.e. a variable length parameter
|
||||
* into the libxml2 representation
|
||||
*/
|
||||
|
||||
xmlChar *
|
||||
pgxml_texttoxmlchar(text *textstring)
|
||||
{
|
||||
xmlChar *res;
|
||||
int32 txsize;
|
||||
|
||||
txsize = VARSIZE(textstring) - VARHDRSZ;
|
||||
res = (xmlChar *) palloc(txsize + 1);
|
||||
memcpy((char *) res, VARDATA(textstring), txsize);
|
||||
res[txsize] = '\0';
|
||||
return res;
|
||||
}
|
||||
|
||||
/* Public visible XPath functions */
|
||||
|
||||
/* This is a "raw" xpath function. Check that it returns child elements
|
||||
* properly
|
||||
*/
|
||||
|
||||
PG_FUNCTION_INFO_V1(xpath_nodeset);
|
||||
|
||||
Datum
|
||||
xpath_nodeset(PG_FUNCTION_ARGS)
|
||||
{
|
||||
xmlChar *xpath, *toptag, *septag;
|
||||
int32 pathsize;
|
||||
text
|
||||
*xpathsupp,
|
||||
*xpres;
|
||||
|
||||
/* PG_GETARG_TEXT_P(0) is document buffer */
|
||||
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
|
||||
|
||||
toptag = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(2));
|
||||
septag = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(3));
|
||||
|
||||
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
|
||||
|
||||
xpath = pgxml_texttoxmlchar(xpathsupp);
|
||||
|
||||
xpres = pgxml_result_to_text(
|
||||
pgxml_xpath(PG_GETARG_TEXT_P(0),xpath),
|
||||
toptag,septag,NULL);
|
||||
|
||||
/* xmlCleanupParser(); done by result_to_text routine */
|
||||
pfree((void *) xpath);
|
||||
|
||||
if (xpres == NULL)
|
||||
{
|
||||
PG_RETURN_NULL();
|
||||
}
|
||||
PG_RETURN_TEXT_P(xpres);
|
||||
}
|
||||
|
||||
// The following function is almost identical, but returns the elements in
|
||||
// a list.
|
||||
|
||||
PG_FUNCTION_INFO_V1(xpath_list);
|
||||
|
||||
Datum
|
||||
xpath_list(PG_FUNCTION_ARGS)
|
||||
{
|
||||
xmlChar *xpath, *plainsep;
|
||||
int32 pathsize;
|
||||
text
|
||||
*xpathsupp,
|
||||
*xpres;
|
||||
|
||||
/* PG_GETARG_TEXT_P(0) is document buffer */
|
||||
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
|
||||
|
||||
plainsep = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(2));
|
||||
|
||||
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
|
||||
|
||||
xpath = pgxml_texttoxmlchar(xpathsupp);
|
||||
|
||||
xpres = pgxml_result_to_text(
|
||||
pgxml_xpath(PG_GETARG_TEXT_P(0),xpath),
|
||||
NULL,NULL,plainsep);
|
||||
|
||||
/* xmlCleanupParser(); done by result_to_text routine */
|
||||
pfree((void *) xpath);
|
||||
|
||||
if (xpres == NULL)
|
||||
{
|
||||
PG_RETURN_NULL();
|
||||
}
|
||||
PG_RETURN_TEXT_P(xpres);
|
||||
}
|
||||
|
||||
|
||||
PG_FUNCTION_INFO_V1(xpath_string);
|
||||
|
||||
Datum
|
||||
xpath_string(PG_FUNCTION_ARGS)
|
||||
{
|
||||
xmlChar *xpath;
|
||||
int32 pathsize;
|
||||
text
|
||||
*xpathsupp,
|
||||
*xpres;
|
||||
|
||||
/* PG_GETARG_TEXT_P(0) is document buffer */
|
||||
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
|
||||
|
||||
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
|
||||
|
||||
/* We encapsulate the supplied path with "string()"
|
||||
* = 8 chars + 1 for NUL at end */
|
||||
/* We could try casting to string using the libxml function? */
|
||||
|
||||
xpath =(xmlChar *) palloc(pathsize + 9);
|
||||
memcpy((char *) (xpath+7), VARDATA(xpathsupp), pathsize);
|
||||
strncpy((char *) xpath, "string(",7);
|
||||
xpath[pathsize+7] = ')';
|
||||
xpath[pathsize+8] = '\0';
|
||||
|
||||
xpres = pgxml_result_to_text(
|
||||
pgxml_xpath(PG_GETARG_TEXT_P(0),xpath),
|
||||
NULL,NULL,NULL);
|
||||
|
||||
xmlCleanupParser();
|
||||
pfree((void *) xpath);
|
||||
|
||||
if (xpres == NULL)
|
||||
{
|
||||
PG_RETURN_NULL();
|
||||
}
|
||||
PG_RETURN_TEXT_P(xpres);
|
||||
}
|
||||
|
||||
|
||||
PG_FUNCTION_INFO_V1(xpath_number);
|
||||
|
||||
Datum
|
||||
xpath_number(PG_FUNCTION_ARGS)
|
||||
{
|
||||
xmlChar *xpath;
|
||||
int32 pathsize;
|
||||
text
|
||||
*xpathsupp;
|
||||
|
||||
float4 fRes;
|
||||
|
||||
xmlXPathObjectPtr res;
|
||||
|
||||
/* PG_GETARG_TEXT_P(0) is document buffer */
|
||||
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
|
||||
|
||||
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
|
||||
|
||||
xpath = pgxml_texttoxmlchar(xpathsupp);
|
||||
|
||||
res = pgxml_xpath(PG_GETARG_TEXT_P(0),xpath);
|
||||
pfree((void *) xpath);
|
||||
|
||||
if (res == NULL)
|
||||
{
|
||||
xmlCleanupParser();
|
||||
PG_RETURN_NULL();
|
||||
}
|
||||
|
||||
fRes = xmlXPathCastToNumber(res);
|
||||
xmlCleanupParser();
|
||||
if (xmlXPathIsNaN(fRes))
|
||||
{
|
||||
PG_RETURN_NULL();
|
||||
}
|
||||
|
||||
PG_RETURN_FLOAT4(fRes);
|
||||
|
||||
}
|
||||
|
||||
|
||||
PG_FUNCTION_INFO_V1(xpath_bool);
|
||||
|
||||
Datum
|
||||
xpath_bool(PG_FUNCTION_ARGS)
|
||||
{
|
||||
xmlChar *xpath;
|
||||
int32 pathsize;
|
||||
text
|
||||
*xpathsupp;
|
||||
|
||||
int bRes;
|
||||
|
||||
xmlXPathObjectPtr res;
|
||||
|
||||
/* PG_GETARG_TEXT_P(0) is document buffer */
|
||||
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
|
||||
|
||||
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
|
||||
|
||||
xpath = pgxml_texttoxmlchar(xpathsupp);
|
||||
|
||||
res = pgxml_xpath(PG_GETARG_TEXT_P(0),xpath);
|
||||
pfree((void *) xpath);
|
||||
|
||||
if (res == NULL)
|
||||
{
|
||||
xmlCleanupParser();
|
||||
PG_RETURN_BOOL(false);
|
||||
}
|
||||
|
||||
bRes = xmlXPathCastToBoolean(res);
|
||||
xmlCleanupParser();
|
||||
PG_RETURN_BOOL(bRes);
|
||||
|
||||
}
|
||||
|
||||
|
||||
|
||||
/* Core function to evaluate XPath query */
|
||||
|
||||
xmlXPathObjectPtr
|
||||
pgxml_xpath(text *document, xmlChar *xpath)
|
||||
{
|
||||
|
||||
xmlDocPtr doctree;
|
||||
xmlXPathContextPtr ctxt;
|
||||
xmlXPathObjectPtr res;
|
||||
|
||||
xmlXPathCompExprPtr comppath;
|
||||
|
||||
int32 docsize;
|
||||
|
||||
|
||||
docsize = VARSIZE(document) - VARHDRSZ;
|
||||
|
||||
pgxml_parser_init();
|
||||
|
||||
doctree = xmlParseMemory((char *) VARDATA(document), docsize);
|
||||
if (doctree == NULL)
|
||||
{ /* not well-formed */
|
||||
return NULL;
|
||||
}
|
||||
|
||||
ctxt = xmlXPathNewContext(doctree);
|
||||
ctxt->node = xmlDocGetRootElement(doctree);
|
||||
|
||||
|
||||
/* compile the path */
|
||||
comppath = xmlXPathCompile(xpath);
|
||||
if (comppath == NULL)
|
||||
{
|
||||
xmlCleanupParser();
|
||||
xmlFreeDoc(doctree);
|
||||
elog_error(ERROR,"XPath Syntax Error",1);
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/* Now evaluate the path expression. */
|
||||
res = xmlXPathCompiledEval(comppath, ctxt);
|
||||
xmlXPathFreeCompExpr(comppath);
|
||||
|
||||
if (res == NULL)
|
||||
{
|
||||
xmlXPathFreeContext(ctxt);
|
||||
// xmlCleanupParser();
|
||||
xmlFreeDoc(doctree);
|
||||
|
||||
return NULL;
|
||||
}
|
||||
/* xmlFreeDoc(doctree); */
|
||||
return res;
|
||||
}
|
||||
|
||||
text
|
||||
*pgxml_result_to_text(xmlXPathObjectPtr res,
|
||||
xmlChar *toptag,
|
||||
xmlChar *septag,
|
||||
xmlChar *plainsep)
|
||||
{
|
||||
xmlChar *xpresstr;
|
||||
int32 ressize;
|
||||
text *xpres;
|
||||
|
||||
if (res == NULL)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
switch (res->type)
|
||||
{
|
||||
case XPATH_NODESET:
|
||||
xpresstr = pgxmlNodeSetToText(res->nodesetval,
|
||||
toptag,
|
||||
septag, plainsep);
|
||||
break;
|
||||
|
||||
case XPATH_STRING:
|
||||
xpresstr = xmlStrdup(res->stringval);
|
||||
break;
|
||||
|
||||
default:
|
||||
elog(NOTICE, "Unsupported XQuery result: %d", res->type);
|
||||
xpresstr = xmlStrdup("<unsupported/>");
|
||||
}
|
||||
|
||||
|
||||
/* Now convert this result back to text */
|
||||
ressize = strlen(xpresstr);
|
||||
xpres = (text *) palloc(ressize + VARHDRSZ);
|
||||
memcpy(VARDATA(xpres), xpresstr, ressize);
|
||||
VARATT_SIZEP(xpres) = ressize + VARHDRSZ;
|
||||
|
||||
/* Free various storage */
|
||||
xmlCleanupParser();
|
||||
/* xmlFreeDoc(doctree); -- will die at end of tuple anyway */
|
||||
|
||||
xmlFree(xpresstr);
|
||||
|
||||
elog_error(ERROR,"XPath error",0);
|
||||
|
||||
|
||||
return xpres;
|
||||
}
|
||||
|
||||
/* xpath_table is a table function. It needs some tidying (as do the
|
||||
* other functions here!
|
||||
*/
|
||||
|
||||
PG_FUNCTION_INFO_V1(xpath_table);
|
||||
|
||||
Datum xpath_table(PG_FUNCTION_ARGS)
|
||||
{
|
||||
/* SPI (input tuple) support */
|
||||
SPITupleTable *tuptable;
|
||||
HeapTuple spi_tuple;
|
||||
TupleDesc spi_tupdesc;
|
||||
|
||||
/* Output tuple (tuplestore) support */
|
||||
Tuplestorestate *tupstore = NULL;
|
||||
TupleDesc ret_tupdesc;
|
||||
HeapTuple ret_tuple;
|
||||
|
||||
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
|
||||
AttInMetadata *attinmeta;
|
||||
MemoryContext per_query_ctx;
|
||||
MemoryContext oldcontext;
|
||||
|
||||
/* Function parameters */
|
||||
char *pkeyfield = GET_STR(PG_GETARG_TEXT_P(0));
|
||||
char *xmlfield = GET_STR(PG_GETARG_TEXT_P(1));
|
||||
char *relname = GET_STR(PG_GETARG_TEXT_P(2));
|
||||
char *xpathset = GET_STR(PG_GETARG_TEXT_P(3));
|
||||
char *condition = GET_STR(PG_GETARG_TEXT_P(4));
|
||||
|
||||
char **values;
|
||||
xmlChar **xpaths;
|
||||
xmlChar *pos;
|
||||
xmlChar *pathsep= "|";
|
||||
|
||||
int numpaths;
|
||||
int ret;
|
||||
int proc;
|
||||
int i;
|
||||
int j;
|
||||
int rownr; /* For issuing multiple rows from one original document */
|
||||
int had_values; /* To determine end of nodeset results */
|
||||
|
||||
StringInfo querysql;
|
||||
|
||||
/* We only have a valid tuple description in table function mode */
|
||||
if (rsinfo->expectedDesc == NULL) {
|
||||
ereport(ERROR,(errcode(ERRCODE_SYNTAX_ERROR),
|
||||
errmsg("xpath_table must be called as a table function")));
|
||||
}
|
||||
|
||||
/* The tuplestore must exist in a higher context than
|
||||
* this function call (per_query_ctx is used) */
|
||||
|
||||
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
|
||||
oldcontext = MemoryContextSwitchTo(per_query_ctx);
|
||||
|
||||
/* Create the tuplestore - SortMem is the max in-memory size before it is
|
||||
* shipped to a disk heap file. Just like ... SortMem!
|
||||
*/
|
||||
|
||||
tupstore = tuplestore_begin_heap(true, false, SortMem);
|
||||
|
||||
MemoryContextSwitchTo(oldcontext);
|
||||
|
||||
/* get the requested return tuple description */
|
||||
ret_tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
|
||||
|
||||
/* At the moment we assume that the returned attributes make sense
|
||||
* for the XPath specififed (i.e. we trust the caller).
|
||||
* It's not fatal if they get it wrong - the input function for the
|
||||
* column type will raise an error if the path result can't be converted
|
||||
* into the correct binary representation.
|
||||
*/
|
||||
|
||||
attinmeta = TupleDescGetAttInMetadata(ret_tupdesc);
|
||||
|
||||
/* We want to materialise because it means that we don't have to
|
||||
* carry libxml2 parser state between invocations of this function
|
||||
*/
|
||||
|
||||
/* check to see if caller supports us returning a tuplestore */
|
||||
if (!rsinfo || !(rsinfo->allowedModes & SFRM_Materialize))
|
||||
ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR),
|
||||
errmsg("xpath_table requires Materialize mode, but it is not "
|
||||
"allowed in this context")));
|
||||
|
||||
// Set return mode and allocate value space.
|
||||
rsinfo->returnMode = SFRM_Materialize;
|
||||
rsinfo->setDesc = ret_tupdesc;
|
||||
|
||||
values = (char **) palloc(ret_tupdesc->natts * sizeof(char *));
|
||||
|
||||
xpaths = (xmlChar **) palloc(ret_tupdesc->natts * sizeof(xmlChar *));
|
||||
|
||||
/* Split XPaths. xpathset is a writable CString. */
|
||||
|
||||
/* Note that we stop splitting once we've done all needed for tupdesc */
|
||||
|
||||
numpaths=0;
|
||||
pos = xpathset;
|
||||
do {
|
||||
xpaths[numpaths] = pos;
|
||||
pos = strstr(pos,pathsep);
|
||||
if (pos != NULL) {
|
||||
*pos = '\0';
|
||||
pos++;
|
||||
}
|
||||
numpaths++;
|
||||
} while ((pos != NULL) && (numpaths < (ret_tupdesc->natts - 1) ));
|
||||
|
||||
/* Now build query */
|
||||
|
||||
querysql = makeStringInfo();
|
||||
|
||||
/* Build initial sql statement */
|
||||
appendStringInfo(querysql, "SELECT %s, %s FROM %s WHERE %s",
|
||||
pkeyfield,
|
||||
xmlfield,
|
||||
relname,
|
||||
condition
|
||||
);
|
||||
|
||||
|
||||
if ((ret = SPI_connect()) < 0) {
|
||||
elog(ERROR, "xpath_table: SPI_connect returned %d", ret);
|
||||
}
|
||||
|
||||
if ((ret = SPI_exec(querysql->data,0)) != SPI_OK_SELECT) {
|
||||
elog(ERROR,"xpath_table: SPI execution failed for query %s",querysql->data);
|
||||
}
|
||||
|
||||
proc= SPI_processed;
|
||||
/* elog(DEBUG1,"xpath_table: SPI returned %d rows",proc); */
|
||||
tuptable = SPI_tuptable;
|
||||
spi_tupdesc = tuptable->tupdesc;
|
||||
|
||||
/* Switch out of SPI context */
|
||||
MemoryContextSwitchTo(oldcontext);
|
||||
|
||||
|
||||
/* Check that SPI returned correct result. If you put a comma into one of
|
||||
* the function parameters, this will catch it when the SPI query returns
|
||||
* e.g. 3 columns.
|
||||
*/
|
||||
|
||||
if (spi_tupdesc->natts != 2) {
|
||||
ereport(ERROR,(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
|
||||
errmsg("Expression returning multiple columns is not valid in parameter list"),
|
||||
errdetail("Expected two columns in SPI result, got %d",spi_tupdesc->natts)));
|
||||
}
|
||||
|
||||
/* Setup the parser. Beware that this must happen in the same context as the
|
||||
* cleanup - which means that any error from here on must do cleanup to
|
||||
* ensure that the entity table doesn't get freed by being out of context.
|
||||
*/
|
||||
pgxml_parser_init();
|
||||
|
||||
/* For each row i.e. document returned from SPI */
|
||||
for (i=0; i < proc; i++) {
|
||||
char *pkey;
|
||||
char *xmldoc;
|
||||
|
||||
xmlDocPtr doctree;
|
||||
xmlXPathContextPtr ctxt;
|
||||
xmlXPathObjectPtr res;
|
||||
xmlChar *resstr;
|
||||
|
||||
|
||||
xmlXPathCompExprPtr comppath;
|
||||
|
||||
/* Extract the row data as C Strings */
|
||||
|
||||
spi_tuple = tuptable->vals[i];
|
||||
pkey = SPI_getvalue(spi_tuple, spi_tupdesc,1);
|
||||
xmldoc = SPI_getvalue(spi_tuple, spi_tupdesc,2);
|
||||
|
||||
|
||||
/* Clear the values array, so that not-well-formed documents
|
||||
* return NULL in all columns.
|
||||
*/
|
||||
|
||||
/* Note that this also means that spare columns will be NULL. */
|
||||
for (j=0; j < ret_tupdesc->natts; j++) {
|
||||
values[j]= NULL;
|
||||
}
|
||||
|
||||
/* Insert primary key */
|
||||
values[0]=pkey;
|
||||
|
||||
/* Parse the document */
|
||||
doctree = xmlParseMemory(xmldoc, strlen(xmldoc));
|
||||
|
||||
if (doctree == NULL)
|
||||
{ /* not well-formed, so output all-NULL tuple */
|
||||
|
||||
ret_tuple = BuildTupleFromCStrings(attinmeta, values);
|
||||
oldcontext = MemoryContextSwitchTo(per_query_ctx);
|
||||
tuplestore_puttuple(tupstore, ret_tuple);
|
||||
MemoryContextSwitchTo(oldcontext);
|
||||
heap_freetuple(ret_tuple);
|
||||
}
|
||||
else
|
||||
{
|
||||
/* New loop here - we have to deal with nodeset results */
|
||||
rownr=0;
|
||||
|
||||
do {
|
||||
/* Now evaluate the set of xpaths. */
|
||||
had_values=0;
|
||||
for (j=0; j < numpaths; j++) {
|
||||
|
||||
ctxt = xmlXPathNewContext(doctree);
|
||||
ctxt->node = xmlDocGetRootElement(doctree);
|
||||
xmlSetGenericErrorFunc(ctxt, pgxml_errorHandler);
|
||||
|
||||
/* compile the path */
|
||||
comppath = xmlXPathCompile(xpaths[j]);
|
||||
if (comppath == NULL)
|
||||
{
|
||||
xmlCleanupParser();
|
||||
xmlFreeDoc(doctree);
|
||||
|
||||
elog_error(ERROR,"XPath Syntax Error",1);
|
||||
|
||||
PG_RETURN_NULL(); /* Keep compiler happy */
|
||||
}
|
||||
|
||||
/* Now evaluate the path expression. */
|
||||
res = xmlXPathCompiledEval(comppath, ctxt);
|
||||
xmlXPathFreeCompExpr(comppath);
|
||||
|
||||
if (res != NULL)
|
||||
{
|
||||
switch (res->type)
|
||||
{
|
||||
case XPATH_NODESET:
|
||||
/* We see if this nodeset has enough nodes */
|
||||
if ((res->nodesetval != NULL) && (rownr < res->nodesetval->nodeNr)) {
|
||||
resstr =
|
||||
xmlXPathCastNodeToString(res->nodesetval->nodeTab[rownr]);
|
||||
had_values=1;
|
||||
} else {
|
||||
resstr = NULL;
|
||||
}
|
||||
|
||||
break;
|
||||
|
||||
case XPATH_STRING:
|
||||
resstr = xmlStrdup(res->stringval);
|
||||
break;
|
||||
|
||||
default:
|
||||
elog(NOTICE, "Unsupported XQuery result: %d", res->type);
|
||||
resstr = xmlStrdup("<unsupported/>");
|
||||
}
|
||||
|
||||
|
||||
// Insert this into the appropriate column in the result tuple.
|
||||
values[j+1] = resstr;
|
||||
}
|
||||
xmlXPathFreeContext(ctxt);
|
||||
}
|
||||
// Now add the tuple to the output, if there is one.
|
||||
if (had_values) {
|
||||
ret_tuple = BuildTupleFromCStrings(attinmeta, values);
|
||||
oldcontext = MemoryContextSwitchTo(per_query_ctx);
|
||||
tuplestore_puttuple(tupstore, ret_tuple);
|
||||
MemoryContextSwitchTo(oldcontext);
|
||||
heap_freetuple(ret_tuple);
|
||||
}
|
||||
|
||||
rownr++;
|
||||
|
||||
} while (had_values);
|
||||
|
||||
}
|
||||
|
||||
xmlFreeDoc(doctree);
|
||||
|
||||
pfree(pkey);
|
||||
pfree(xmldoc);
|
||||
}
|
||||
|
||||
xmlCleanupParser();
|
||||
/* Needed to flag completeness in 7.3.1. 7.4 defines it as a no-op. */
|
||||
tuplestore_donestoring(tupstore);
|
||||
|
||||
SPI_finish();
|
||||
|
||||
rsinfo->setResult=tupstore;
|
||||
|
||||
/*
|
||||
* SFRM_Materialize mode expects us to return a NULL Datum. The actual
|
||||
* tuples are in our tuplestore and passed back through
|
||||
* rsinfo->setResult. rsinfo->setDesc is set to the tuple description
|
||||
* that we actually used to build our tuples with, so the caller can
|
||||
* verify we did what it was expecting.
|
||||
*/
|
||||
return (Datum) 0;
|
||||
|
||||
}
|
||||
Reference in New Issue
Block a user