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postgresql/contrib/ltree/ltree_op.c
Tom Lane 220db7ccd8 Simplify and standardize conversions between TEXT datums and ordinary C 
strings.  This patch introduces four support functions cstring_to_text,
cstring_to_text_with_len, text_to_cstring, and text_to_cstring_buffer, and
two macros CStringGetTextDatum and TextDatumGetCString.  A number of
existing macros that provided variants on these themes were removed.

Most of the places that need to make such conversions now require just one
function or macro call, in place of the multiple notational layers that used
to be needed.  There are no longer any direct calls of textout or textin,
and we got most of the places that were using handmade conversions via
memcpy (there may be a few still lurking, though).

This commit doesn't make any serious effort to eliminate transient memory
leaks caused by detoasting toasted text objects before they reach
text_to_cstring.  We changed PG_GETARG_TEXT_P to PG_GETARG_TEXT_PP in a few
places where it was easy, but much more could be done.

Brendan Jurd and Tom Lane
2008-03-25 22:42:46 +00:00

667 lines
13 KiB
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/*
* op function for ltree
* Teodor Sigaev <teodor@stack.net>
* $PostgreSQL: pgsql/contrib/ltree/ltree_op.c,v 1.18 2008/03/25 22:42:41 tgl Exp $
*/
#include "ltree.h"
#include <ctype.h>
#include "catalog/pg_statistic.h"
#include "utils/lsyscache.h"
#include "utils/selfuncs.h"
#include "utils/syscache.h"
PG_MODULE_MAGIC;
/* compare functions */
PG_FUNCTION_INFO_V1(ltree_cmp);
PG_FUNCTION_INFO_V1(ltree_lt);
PG_FUNCTION_INFO_V1(ltree_le);
PG_FUNCTION_INFO_V1(ltree_eq);
PG_FUNCTION_INFO_V1(ltree_ne);
PG_FUNCTION_INFO_V1(ltree_ge);
PG_FUNCTION_INFO_V1(ltree_gt);
PG_FUNCTION_INFO_V1(nlevel);
PG_FUNCTION_INFO_V1(ltree_isparent);
PG_FUNCTION_INFO_V1(ltree_risparent);
PG_FUNCTION_INFO_V1(subltree);
PG_FUNCTION_INFO_V1(subpath);
PG_FUNCTION_INFO_V1(ltree_index);
PG_FUNCTION_INFO_V1(ltree_addltree);
PG_FUNCTION_INFO_V1(ltree_addtext);
PG_FUNCTION_INFO_V1(ltree_textadd);
PG_FUNCTION_INFO_V1(lca);
PG_FUNCTION_INFO_V1(ltree2text);
PG_FUNCTION_INFO_V1(text2ltree);
PG_FUNCTION_INFO_V1(ltreeparentsel);
Datum ltree_cmp(PG_FUNCTION_ARGS);
Datum ltree_lt(PG_FUNCTION_ARGS);
Datum ltree_le(PG_FUNCTION_ARGS);
Datum ltree_eq(PG_FUNCTION_ARGS);
Datum ltree_ne(PG_FUNCTION_ARGS);
Datum ltree_ge(PG_FUNCTION_ARGS);
Datum ltree_gt(PG_FUNCTION_ARGS);
Datum nlevel(PG_FUNCTION_ARGS);
Datum subltree(PG_FUNCTION_ARGS);
Datum subpath(PG_FUNCTION_ARGS);
Datum ltree_index(PG_FUNCTION_ARGS);
Datum ltree_addltree(PG_FUNCTION_ARGS);
Datum ltree_addtext(PG_FUNCTION_ARGS);
Datum ltree_textadd(PG_FUNCTION_ARGS);
Datum lca(PG_FUNCTION_ARGS);
Datum ltree2text(PG_FUNCTION_ARGS);
Datum text2ltree(PG_FUNCTION_ARGS);
Datum ltreeparentsel(PG_FUNCTION_ARGS);
int
ltree_compare(const ltree * a, const ltree * b)
{
ltree_level *al = LTREE_FIRST(a);
ltree_level *bl = LTREE_FIRST(b);
int an = a->numlevel;
int bn = b->numlevel;
int res = 0;
while (an > 0 && bn > 0)
{
if ((res = strncmp(al->name, bl->name, Min(al->len, bl->len))) == 0)
{
if (al->len != bl->len)
return (al->len - bl->len) * 10 * (an + 1);
}
else
return res * 10 * (an + 1);
an--;
bn--;
al = LEVEL_NEXT(al);
bl = LEVEL_NEXT(bl);
}
return (a->numlevel - b->numlevel) * 10 * (an + 1);
}
#define RUNCMP \
ltree *a = PG_GETARG_LTREE(0); \
ltree *b = PG_GETARG_LTREE(1); \
int res = ltree_compare(a,b); \
PG_FREE_IF_COPY(a,0); \
PG_FREE_IF_COPY(b,1); \
Datum
ltree_cmp(PG_FUNCTION_ARGS)
{
RUNCMP
PG_RETURN_INT32(res);
}
Datum
ltree_lt(PG_FUNCTION_ARGS)
{
RUNCMP
PG_RETURN_BOOL((res < 0) ? true : false);
}
Datum
ltree_le(PG_FUNCTION_ARGS)
{
RUNCMP
PG_RETURN_BOOL((res <= 0) ? true : false);
}
Datum
ltree_eq(PG_FUNCTION_ARGS)
{
RUNCMP
PG_RETURN_BOOL((res == 0) ? true : false);
}
Datum
ltree_ge(PG_FUNCTION_ARGS)
{
RUNCMP
PG_RETURN_BOOL((res >= 0) ? true : false);
}
Datum
ltree_gt(PG_FUNCTION_ARGS)
{
RUNCMP
PG_RETURN_BOOL((res > 0) ? true : false);
}
Datum
ltree_ne(PG_FUNCTION_ARGS)
{
RUNCMP
PG_RETURN_BOOL((res != 0) ? true : false);
}
Datum
nlevel(PG_FUNCTION_ARGS)
{
ltree *a = PG_GETARG_LTREE(0);
int res = a->numlevel;
PG_FREE_IF_COPY(a, 0);
PG_RETURN_INT32(res);
}
bool
inner_isparent(const ltree * c, const ltree * p)
{
ltree_level *cl = LTREE_FIRST(c);
ltree_level *pl = LTREE_FIRST(p);
int pn = p->numlevel;
if (pn > c->numlevel)
return false;
while (pn > 0)
{
if (cl->len != pl->len)
return false;
if (strncmp(cl->name, pl->name, cl->len))
return false;
pn--;
cl = LEVEL_NEXT(cl);
pl = LEVEL_NEXT(pl);
}
return true;
}
Datum
ltree_isparent(PG_FUNCTION_ARGS)
{
ltree *c = PG_GETARG_LTREE(1);
ltree *p = PG_GETARG_LTREE(0);
bool res = inner_isparent(c, p);
PG_FREE_IF_COPY(c, 1);
PG_FREE_IF_COPY(p, 0);
PG_RETURN_BOOL(res);
}
Datum
ltree_risparent(PG_FUNCTION_ARGS)
{
ltree *c = PG_GETARG_LTREE(0);
ltree *p = PG_GETARG_LTREE(1);
bool res = inner_isparent(c, p);
PG_FREE_IF_COPY(c, 0);
PG_FREE_IF_COPY(p, 1);
PG_RETURN_BOOL(res);
}
static ltree *
inner_subltree(ltree * t, int4 startpos, int4 endpos)
{
char *start = NULL,
*end = NULL;
ltree_level *ptr = LTREE_FIRST(t);
ltree *res;
int i;
if (startpos < 0 || endpos < 0 || startpos >= t->numlevel || startpos > endpos)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid positions")));
if (endpos > t->numlevel)
endpos = t->numlevel;
start = end = (char *) ptr;
for (i = 0; i < endpos; i++)
{
if (i == startpos)
start = (char *) ptr;
if (i == endpos - 1)
{
end = (char *) LEVEL_NEXT(ptr);
break;
}
ptr = LEVEL_NEXT(ptr);
}
res = (ltree *) palloc(LTREE_HDRSIZE + (end - start));
SET_VARSIZE(res, LTREE_HDRSIZE + (end - start));
res->numlevel = endpos - startpos;
memcpy(LTREE_FIRST(res), start, end - start);
return res;
}
Datum
subltree(PG_FUNCTION_ARGS)
{
ltree *t = PG_GETARG_LTREE(0);
ltree *res = inner_subltree(t, PG_GETARG_INT32(1), PG_GETARG_INT32(2));
PG_FREE_IF_COPY(t, 0);
PG_RETURN_POINTER(res);
}
Datum
subpath(PG_FUNCTION_ARGS)
{
ltree *t = PG_GETARG_LTREE(0);
int4 start = PG_GETARG_INT32(1);
int4 len = (fcinfo->nargs == 3) ? PG_GETARG_INT32(2) : 0;
int4 end;
ltree *res;
end = start + len;
if (start < 0)
{
start = t->numlevel + start;
end = start + len;
}
if (start < 0)
{ /* start > t->numlevel */
start = t->numlevel + start;
end = start + len;
}
if (len < 0)
end = t->numlevel + len;
else if (len == 0)
end = (fcinfo->nargs == 3) ? start : 0xffff;
res = inner_subltree(t, start, end);
PG_FREE_IF_COPY(t, 0);
PG_RETURN_POINTER(res);
}
static ltree *
ltree_concat(ltree * a, ltree * b)
{
ltree *r;
r = (ltree *) palloc(VARSIZE(a) + VARSIZE(b) - LTREE_HDRSIZE);
SET_VARSIZE(r, VARSIZE(a) + VARSIZE(b) - LTREE_HDRSIZE);
r->numlevel = a->numlevel + b->numlevel;
memcpy(LTREE_FIRST(r), LTREE_FIRST(a), VARSIZE(a) - LTREE_HDRSIZE);
memcpy(((char *) LTREE_FIRST(r)) + VARSIZE(a) - LTREE_HDRSIZE,
LTREE_FIRST(b),
VARSIZE(b) - LTREE_HDRSIZE);
return r;
}
Datum
ltree_addltree(PG_FUNCTION_ARGS)
{
ltree *a = PG_GETARG_LTREE(0);
ltree *b = PG_GETARG_LTREE(1);
ltree *r;
r = ltree_concat(a, b);
PG_FREE_IF_COPY(a, 0);
PG_FREE_IF_COPY(b, 1);
PG_RETURN_POINTER(r);
}
Datum
ltree_addtext(PG_FUNCTION_ARGS)
{
ltree *a = PG_GETARG_LTREE(0);
text *b = PG_GETARG_TEXT_PP(1);
char *s;
ltree *r,
*tmp;
s = text_to_cstring(b);
tmp = (ltree *) DatumGetPointer(DirectFunctionCall1(ltree_in,
PointerGetDatum(s)));
pfree(s);
r = ltree_concat(a, tmp);
pfree(tmp);
PG_FREE_IF_COPY(a, 0);
PG_FREE_IF_COPY(b, 1);
PG_RETURN_POINTER(r);
}
Datum
ltree_index(PG_FUNCTION_ARGS)
{
ltree *a = PG_GETARG_LTREE(0);
ltree *b = PG_GETARG_LTREE(1);
int start = (fcinfo->nargs == 3) ? PG_GETARG_INT32(2) : 0;
int i,
j;
ltree_level *startptr,
*aptr,
*bptr;
bool found = false;
if (start < 0)
{
if (-start >= a->numlevel)
start = 0;
else
start = (int) (a->numlevel) + start;
}
if (a->numlevel - start < b->numlevel || a->numlevel == 0 || b->numlevel == 0)
{
PG_FREE_IF_COPY(a, 0);
PG_FREE_IF_COPY(b, 1);
PG_RETURN_INT32(-1);
}
startptr = LTREE_FIRST(a);
for (i = 0; i <= a->numlevel - b->numlevel; i++)
{
if (i >= start)
{
aptr = startptr;
bptr = LTREE_FIRST(b);
for (j = 0; j < b->numlevel; j++)
{
if (!(aptr->len == bptr->len && strncmp(aptr->name, bptr->name, aptr->len) == 0))
break;
aptr = LEVEL_NEXT(aptr);
bptr = LEVEL_NEXT(bptr);
}
if (j == b->numlevel)
{
found = true;
break;
}
}
startptr = LEVEL_NEXT(startptr);
}
if (!found)
i = -1;
PG_FREE_IF_COPY(a, 0);
PG_FREE_IF_COPY(b, 1);
PG_RETURN_INT32(i);
}
Datum
ltree_textadd(PG_FUNCTION_ARGS)
{
ltree *a = PG_GETARG_LTREE(1);
text *b = PG_GETARG_TEXT_PP(0);
char *s;
ltree *r,
*tmp;
s = text_to_cstring(b);
tmp = (ltree *) DatumGetPointer(DirectFunctionCall1(ltree_in,
PointerGetDatum(s)));
pfree(s);
r = ltree_concat(tmp, a);
pfree(tmp);
PG_FREE_IF_COPY(a, 1);
PG_FREE_IF_COPY(b, 0);
PG_RETURN_POINTER(r);
}
ltree *
lca_inner(ltree ** a, int len)
{
int tmp,
num = ((*a)->numlevel) ? (*a)->numlevel - 1 : 0;
ltree **ptr = a + 1;
int i,
reslen = LTREE_HDRSIZE;
ltree_level *l1,
*l2;
ltree *res;
if ((*a)->numlevel == 0)
return NULL;
while (ptr - a < len)
{
if ((*ptr)->numlevel == 0)
return NULL;
else if ((*ptr)->numlevel == 1)
num = 0;
else
{
l1 = LTREE_FIRST(*a);
l2 = LTREE_FIRST(*ptr);
tmp = num;
num = 0;
for (i = 0; i < Min(tmp, (*ptr)->numlevel - 1); i++)
{
if (l1->len == l2->len && strncmp(l1->name, l2->name, l1->len) == 0)
num = i + 1;
else
break;
l1 = LEVEL_NEXT(l1);
l2 = LEVEL_NEXT(l2);
}
}
ptr++;
}
l1 = LTREE_FIRST(*a);
for (i = 0; i < num; i++)
{
reslen += MAXALIGN(l1->len + LEVEL_HDRSIZE);
l1 = LEVEL_NEXT(l1);
}
res = (ltree *) palloc(reslen);
SET_VARSIZE(res, reslen);
res->numlevel = num;
l1 = LTREE_FIRST(*a);
l2 = LTREE_FIRST(res);
for (i = 0; i < num; i++)
{
memcpy(l2, l1, MAXALIGN(l1->len + LEVEL_HDRSIZE));
l1 = LEVEL_NEXT(l1);
l2 = LEVEL_NEXT(l2);
}
return res;
}
Datum
lca(PG_FUNCTION_ARGS)
{
int i;
ltree **a,
*res;
a = (ltree **) palloc(sizeof(ltree *) * fcinfo->nargs);
for (i = 0; i < fcinfo->nargs; i++)
a[i] = PG_GETARG_LTREE(i);
res = lca_inner(a, (int) fcinfo->nargs);
for (i = 0; i < fcinfo->nargs; i++)
PG_FREE_IF_COPY(a[i], i);
pfree(a);
if (res)
PG_RETURN_POINTER(res);
else
PG_RETURN_NULL();
}
Datum
text2ltree(PG_FUNCTION_ARGS)
{
text *in = PG_GETARG_TEXT_PP(0);
char *s;
ltree *out;
s = text_to_cstring(in);
out = (ltree *) DatumGetPointer(DirectFunctionCall1(ltree_in,
PointerGetDatum(s)));
pfree(s);
PG_FREE_IF_COPY(in, 0);
PG_RETURN_POINTER(out);
}
Datum
ltree2text(PG_FUNCTION_ARGS)
{
ltree *in = PG_GETARG_LTREE(0);
char *ptr;
int i;
ltree_level *curlevel;
text *out;
out = (text *) palloc(VARSIZE(in) + VARHDRSZ);
ptr = VARDATA(out);
curlevel = LTREE_FIRST(in);
for (i = 0; i < in->numlevel; i++)
{
if (i != 0)
{
*ptr = '.';
ptr++;
}
memcpy(ptr, curlevel->name, curlevel->len);
ptr += curlevel->len;
curlevel = LEVEL_NEXT(curlevel);
}
SET_VARSIZE(out, ptr - ((char *) out));
PG_FREE_IF_COPY(in, 0);
PG_RETURN_POINTER(out);
}
#define DEFAULT_PARENT_SEL 0.001
/*
* ltreeparentsel - Selectivity of parent relationship for ltree data types.
*/
Datum
ltreeparentsel(PG_FUNCTION_ARGS)
{
PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0);
Oid operator = PG_GETARG_OID(1);
List *args = (List *) PG_GETARG_POINTER(2);
int varRelid = PG_GETARG_INT32(3);
VariableStatData vardata;
Node *other;
bool varonleft;
double selec;
/*
* If expression is not variable <@ something or something <@ variable,
* then punt and return a default estimate.
*/
if (!get_restriction_variable(root, args, varRelid,
&vardata, &other, &varonleft))
PG_RETURN_FLOAT8(DEFAULT_PARENT_SEL);
/*
* If the something is a NULL constant, assume operator is strict and
* return zero, ie, operator will never return TRUE.
*/
if (IsA(other, Const) &&
((Const *) other)->constisnull)
{
ReleaseVariableStats(vardata);
PG_RETURN_FLOAT8(0.0);
}
if (IsA(other, Const))
{
/* Variable is being compared to a known non-null constant */
Datum constval = ((Const *) other)->constvalue;
FmgrInfo contproc;
double mcvsum;
double mcvsel;
double nullfrac;
int hist_size;
fmgr_info(get_opcode(operator), &contproc);
/*
* Is the constant "<@" to any of the column's most common values?
*/
mcvsel = mcv_selectivity(&vardata, &contproc, constval, varonleft,
&mcvsum);
/*
* If the histogram is large enough, see what fraction of it the
* constant is "<@" to, and assume that's representative of the
* non-MCV population. Otherwise use the default selectivity for the
* non-MCV population.
*/
selec = histogram_selectivity(&vardata, &contproc,
constval, varonleft,
10, 1, &hist_size);
if (selec < 0)
{
/* Nope, fall back on default */
selec = DEFAULT_PARENT_SEL;
}
else if (hist_size < 100)
{
/*
* For histogram sizes from 10 to 100, we combine the
* histogram and default selectivities, putting increasingly
* more trust in the histogram for larger sizes.
*/
double hist_weight = hist_size / 100.0;
selec = selec * hist_weight +
DEFAULT_PARENT_SEL * (1.0 - hist_weight);
}
/* In any case, don't believe extremely small or large estimates. */
if (selec < 0.0001)
selec = 0.0001;
else if (selec > 0.9999)
selec = 0.9999;
if (HeapTupleIsValid(vardata.statsTuple))
nullfrac = ((Form_pg_statistic) GETSTRUCT(vardata.statsTuple))->stanullfrac;
else
nullfrac = 0.0;
/*
* Now merge the results from the MCV and histogram calculations,
* realizing that the histogram covers only the non-null values that
* are not listed in MCV.
*/
selec *= 1.0 - nullfrac - mcvsum;
selec += mcvsel;
}
else
selec = DEFAULT_PARENT_SEL;
ReleaseVariableStats(vardata);
/* result should be in range, but make sure... */
CLAMP_PROBABILITY(selec);
PG_RETURN_FLOAT8((float8) selec);
}
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