mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-08-25 04:27:20 +02:00
311 lines
7.0 KiB
C
311 lines
7.0 KiB
C
/********************************************************
|
|
* Interface code to parse an XML document using expat
|
|
********************************************************/
|
|
|
|
#include "postgres.h"
|
|
#include "fmgr.h"
|
|
|
|
#include "expat.h"
|
|
#include "pgxml.h"
|
|
|
|
/* Memory management - we make expat use standard pg MM */
|
|
|
|
XML_Memory_Handling_Suite mhs;
|
|
|
|
/* passthrough functions (palloc is a macro) */
|
|
|
|
static void *pgxml_palloc(size_t size)
|
|
{
|
|
return palloc(size);
|
|
}
|
|
|
|
static void *pgxml_repalloc(void *ptr, size_t size)
|
|
{
|
|
return repalloc(ptr,size);
|
|
}
|
|
|
|
static void pgxml_pfree(void *ptr)
|
|
{
|
|
return pfree(ptr);
|
|
}
|
|
|
|
static void pgxml_mhs_init()
|
|
{
|
|
mhs.malloc_fcn = pgxml_palloc;
|
|
mhs.realloc_fcn = pgxml_repalloc;
|
|
mhs.free_fcn = pgxml_pfree;
|
|
}
|
|
|
|
static void pgxml_handler_init()
|
|
{
|
|
/* This code should set up the relevant handlers from user-supplied
|
|
settings. Quite how these settings are made is another matter :) */
|
|
}
|
|
|
|
/* Returns true if document is well-formed */
|
|
|
|
PG_FUNCTION_INFO_V1(pgxml_parse);
|
|
|
|
Datum
|
|
pgxml_parse(PG_FUNCTION_ARGS)
|
|
{
|
|
/* called as pgxml_parse(document) */
|
|
XML_Parser p;
|
|
text *t = PG_GETARG_TEXT_P(0); /*document buffer */
|
|
int32 docsize = VARSIZE(t) - VARHDRSZ;
|
|
|
|
pgxml_mhs_init();
|
|
|
|
pgxml_handler_init();
|
|
|
|
p = XML_ParserCreate_MM(NULL,&mhs,NULL);
|
|
if (! p) {
|
|
elog(ERROR, "pgxml: Could not create expat parser");
|
|
PG_RETURN_NULL(); /* seems appropriate if we couldn't parse */
|
|
}
|
|
|
|
if (! XML_Parse(p, (char *)VARDATA(t) , docsize, 1)) {
|
|
/* elog(NOTICE, "Parse error at line %d:%s",
|
|
XML_GetCurrentLineNumber(p),
|
|
XML_ErrorString(XML_GetErrorCode(p))); */
|
|
XML_ParserFree(p);
|
|
PG_RETURN_BOOL(false);
|
|
}
|
|
|
|
XML_ParserFree(p);
|
|
PG_RETURN_BOOL(true);
|
|
}
|
|
|
|
/* XPath handling functions */
|
|
|
|
/* XPath support here is for a very skeletal kind of XPath!
|
|
It was easy to program though... */
|
|
|
|
/* This first is the core function that builds a result set. The
|
|
actual functions called by the user manipulate that result set
|
|
in various ways.
|
|
*/
|
|
|
|
static XPath_Results *build_xpath_results(text *doc, text *pathstr)
|
|
{
|
|
XPath_Results *xpr;
|
|
char *res;
|
|
pgxml_udata *udata;
|
|
XML_Parser p;
|
|
int32 docsize;
|
|
|
|
xpr = (XPath_Results *) palloc((sizeof(XPath_Results)));
|
|
memset((void *)xpr, 0, sizeof(XPath_Results));
|
|
xpr->rescount=0;
|
|
|
|
docsize=VARSIZE(doc)-VARHDRSZ;
|
|
|
|
/* res isn't going to be the real return type, it is just a buffer */
|
|
|
|
res = (char *) palloc(docsize);
|
|
memset((void *)res, 0, docsize);
|
|
|
|
xpr->resbuf = res;
|
|
|
|
udata = (pgxml_udata *) palloc((sizeof(pgxml_udata)));
|
|
memset((void *)udata,0,sizeof(pgxml_udata));
|
|
|
|
udata->currentpath[0]='\0';
|
|
udata->textgrab=0;
|
|
|
|
udata->path= (char *) palloc(VARSIZE(pathstr));
|
|
memcpy(udata->path, VARDATA(pathstr), VARSIZE(pathstr)-VARHDRSZ);
|
|
|
|
udata->path[VARSIZE(pathstr)-VARHDRSZ]='\0';
|
|
|
|
udata->resptr = res;
|
|
udata->reslen = 0;
|
|
|
|
udata->xpres = xpr;
|
|
|
|
/* Now fire up the parser */
|
|
pgxml_mhs_init();
|
|
|
|
p = XML_ParserCreate_MM(NULL,&mhs,NULL);
|
|
if (! p) {
|
|
elog(ERROR, "pgxml: Could not create expat parser");
|
|
pfree(xpr);
|
|
pfree(udata->path);
|
|
pfree(udata);
|
|
pfree(res);
|
|
return NULL;
|
|
}
|
|
XML_SetUserData(p, (void *)udata);
|
|
|
|
/* Set the handlers */
|
|
|
|
XML_SetElementHandler(p, pgxml_starthandler, pgxml_endhandler);
|
|
XML_SetCharacterDataHandler(p, pgxml_charhandler);
|
|
|
|
if (! XML_Parse(p, (char *)VARDATA(doc) , docsize, 1)) {
|
|
/* elog(NOTICE, "Parse error at line %d:%s",
|
|
XML_GetCurrentLineNumber(p),
|
|
XML_ErrorString(XML_GetErrorCode(p))); */
|
|
XML_ParserFree(p);
|
|
pfree(xpr);
|
|
pfree(udata->path);
|
|
pfree(udata);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
pfree(udata->path);
|
|
pfree(udata);
|
|
XML_ParserFree(p);
|
|
return xpr;
|
|
}
|
|
|
|
|
|
PG_FUNCTION_INFO_V1(pgxml_xpath);
|
|
|
|
Datum
|
|
pgxml_xpath(PG_FUNCTION_ARGS)
|
|
{
|
|
/* called as pgxml_xpath(document,pathstr, index) for the moment*/
|
|
|
|
XPath_Results *xpresults;
|
|
text *restext;
|
|
|
|
text *t = PG_GETARG_TEXT_P(0); /*document buffer */
|
|
text *t2= PG_GETARG_TEXT_P(1);
|
|
int32 ind = PG_GETARG_INT32(2) - 1;
|
|
|
|
xpresults = build_xpath_results(t,t2);
|
|
|
|
/* This needs to be changed depending on the mechanism for returning
|
|
our set of results. */
|
|
|
|
if (xpresults==NULL) /*parse error (not WF or parser failure) */
|
|
{
|
|
PG_RETURN_NULL();
|
|
}
|
|
|
|
if (ind >= (xpresults->rescount))
|
|
{
|
|
PG_RETURN_NULL();
|
|
}
|
|
|
|
restext = (text *) palloc(xpresults->reslens[ind]+VARHDRSZ);
|
|
memcpy(VARDATA(restext),xpresults->results[ind],xpresults->reslens[ind]);
|
|
|
|
VARATT_SIZEP(restext) = xpresults->reslens[ind]+VARHDRSZ;
|
|
|
|
pfree(xpresults->resbuf);
|
|
pfree(xpresults);
|
|
|
|
PG_RETURN_TEXT_P(restext);
|
|
}
|
|
|
|
|
|
static void pgxml_pathcompare(void *userData)
|
|
{
|
|
char *matchpos;
|
|
|
|
matchpos=strstr(UD->currentpath, UD->path);
|
|
|
|
if (matchpos == NULL) { /* Should we have more logic here ? */
|
|
if (UD->textgrab) {
|
|
UD->textgrab=0;
|
|
pgxml_finalisegrabbedtext(userData);
|
|
}
|
|
return;
|
|
}
|
|
/* OK, we have a match of some sort. Now we need to check that
|
|
our match is anchored to the *end* of the string AND
|
|
that it is immediately preceded by a '/'*/
|
|
/* This test wouldn't work if strlen (UD->path) overran the length
|
|
of the currentpath, but that's not possible because we got a match! */
|
|
|
|
if ((matchpos + strlen(UD->path))[0]=='\0')
|
|
{
|
|
if ((UD->path)[0]=='/') {
|
|
if (matchpos == UD->currentpath) {
|
|
UD->textgrab=1;
|
|
}
|
|
} else {
|
|
if ((matchpos-1)[0]=='/') {
|
|
UD->textgrab=1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static void pgxml_starthandler(void *userData, const XML_Char *name,
|
|
const XML_Char **atts)
|
|
{
|
|
|
|
char sepstr[]="/";
|
|
|
|
if ((strlen(name)+strlen(UD->currentpath))>MAXPATHLENGTH-2) {
|
|
elog(NOTICE,"Path too long");
|
|
} else {
|
|
strncat(UD->currentpath,sepstr,1);
|
|
strcat(UD->currentpath, name);
|
|
}
|
|
if (UD->textgrab)
|
|
{
|
|
/* Depending on user preference, should we "reconstitute"
|
|
the element into the result text?
|
|
*/
|
|
} else {
|
|
pgxml_pathcompare(userData);
|
|
}
|
|
}
|
|
|
|
static void pgxml_endhandler(void *userData, const XML_Char *name)
|
|
{
|
|
/* Start by removing the current element off the end of the
|
|
currentpath */
|
|
|
|
char *sepptr;
|
|
|
|
sepptr=strrchr(UD->currentpath,'/');
|
|
if (sepptr==NULL) {
|
|
elog(ERROR,"There's a problem...");
|
|
sepptr=UD->currentpath;
|
|
}
|
|
if (strcmp(name, sepptr+1) !=0) {
|
|
elog(NOTICE,"Wanted [%s], got [%s]",sepptr,name);
|
|
/* unmatched entry, so do nothing */
|
|
} else {
|
|
sepptr[0]='\0'; /* Chop that element off the end */
|
|
}
|
|
|
|
if (UD->textgrab) {
|
|
pgxml_pathcompare(userData);
|
|
}
|
|
|
|
}
|
|
|
|
static void pgxml_charhandler(void *userData, const XML_Char *s, int len)
|
|
{
|
|
if (UD->textgrab) {
|
|
if (len>0) {
|
|
memcpy(UD->resptr,s,len);
|
|
UD->resptr += len;
|
|
UD->reslen += len;
|
|
}
|
|
}
|
|
}
|
|
/* Should I be using PG list types here? */
|
|
|
|
static void pgxml_finalisegrabbedtext(void *userData)
|
|
{
|
|
/* In res/reslen, we have a single result. */
|
|
UD->xpres->results[UD->xpres->rescount]= UD->resptr - UD->reslen;
|
|
UD->xpres->reslens[UD->xpres->rescount]= UD->reslen;
|
|
UD->reslen=0;
|
|
UD->xpres->rescount++;
|
|
|
|
/* This effectively concatenates all the results together but we
|
|
do know where one ends and the next begins */
|
|
}
|
|
|
|
|
|
|