unite_sfunc made always copy input array in long lived memory context.

It should now work with safer memory.

git-svn-id: http://svn.osgeo.org/postgis/trunk@331 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/postgis_geos.c b/postgis_geos.c
index 589dca113a6942103aaa25083e41e2abc95be23b..3af639afeec936bc7585f416b31132b8718c152b 100644 (file)
--- a/postgis_geos.c
+++ b/postgis_geos.c
@@ -10,6 +10,10 @@
  *
  **********************************************************************
  * $Log$
+ * Revision 1.16  2003/10/27 23:44:54  strk
+ * unite_sfunc made always copy input array in long lived memory context.
+ * It should now work with safer memory.
+ *
  * Revision 1.15  2003/10/27 20:13:05  strk
  * Made GeomUnion release memory soon, Added fastunion support functions
  *
@@ -241,26 +245,30 @@ resize_ptrArrayType(ArrayType *a, int num)
  * Will DETOAST given geometry and put a pointer to it
  * in the given array. DETOASTED value is first copied
  * to a safe memory context to avoid premature deletion.
- *
- * WARNING: array resize is not checked for memory
- * context. Might use instable memory!! --strk(TODO);
- *
  */
+#define DEBUG 
 PG_FUNCTION_INFO_V1(unite_sfunc);
 Datum unite_sfunc(PG_FUNCTION_ARGS)
 {
        ArrayType *array;
-       int nelems;
+       int nelems, nbytes;
        Datum datum;
        GEOMETRY *geom, *tmpgeom;
        ArrayType *result;
        Pointer **pointers;
-#ifdef USE_BOGUS_MEMORY_CONTEXT_SWITCHING
        MemoryContext oldcontext; 
-#endif
 
-       array = (ArrayType *) PG_GETARG_ARRAYTYPE_P(0);
-       nelems = ArrayGetNItems(ARR_NDIM(array), ARR_DIMS(array));
+       datum = PG_GETARG_DATUM(0);
+       if ( (Pointer *)datum == NULL ) {
+               array = NULL;
+               nelems = 0;
+#ifdef DEBUG
+               elog(NOTICE, "unite_sfunc: NULL array, nelems=%d", nelems);
+#endif
+       } else {
+               array = (ArrayType *) PG_DETOAST_DATUM_COPY(datum);
+               nelems = ArrayGetNItems(ARR_NDIM(array), ARR_DIMS(array));
+       }
 
        datum = PG_GETARG_DATUM(1);
        // Do nothing, return state array
@@ -271,40 +279,46 @@ Datum unite_sfunc(PG_FUNCTION_ARGS)
        }
 
        /*
-        * Find a way to directly detoast datum in
-        * flinfo->fcinfo->fn_mcxt context.
-        * ( this way we'll reduce a memory copy I guess)
-        *      --strk(TODO);
+        * Switch to * flinfo->fcinfo->fn_mcxt
+        * memory context to be sure both detoasted
+        * geometry AND array of pointers to it
+        * last till the call to unite_finalfunc.
         */
-#ifdef USE_BOGUS_MEMORY_CONTEXT_SWITCHING
        oldcontext = MemoryContextSwitchTo(fcinfo->flinfo->fn_mcxt);
-       geom = (GEOMETRY *)PG_DETOAST_DATUM(datum); 
-       MemoryContextSwitchTo(oldcontext);
-#else
-       tmpgeom = (GEOMETRY *)PG_DETOAST_DATUM(datum); 
-       geom = (GEOMETRY *) MemoryContextAlloc(
-               fcinfo->flinfo->fn_mcxt, tmpgeom->size);
-       memcpy(geom, tmpgeom, tmpgeom->size);
-       if ( (GEOMETRY *)datum != tmpgeom ) pfree(tmpgeom);
-#endif
 
-       // Add given geometry to state array 
-       nelems++;
-       //elog(NOTICE, "unite_sfunc: adding %p, nelems=%d", geom, nelems);
+       /* Make a DETOASTED copy of input geometry */
+       geom = (GEOMETRY *)PG_DETOAST_DATUM_COPY(datum); 
+
+#ifdef DEBUG
+       elog(NOTICE, "unite_sfunc: adding %p (nelems=%d)", geom, nelems);
+#endif
 
        /*
         * Might use a more optimized version instead of repalloc'ing
         * at every iteration. This is not the bottleneck anyway.
-        *
-        * WARNING: should use fcinfo->flinfo->fn_mcxt
-        * memory context for the array too!
-        *  --strk(TODO);
+        *              --strk(TODO);
         */
-       result = resize_ptrArrayType(array, nelems);
+       ++nelems;
+       nbytes = ARR_OVERHEAD(1) + sizeof(Pointer *) * nelems;
+       if ( ! array ) {
+               result = (ArrayType *) palloc(nbytes);
+               result->size = nbytes;
+               result->ndim = 1;
+               *((int *) ARR_DIMS(result)) = nelems;
+       } else {
+               result = (ArrayType *) repalloc(array, nbytes);
+               result->size = nbytes;
+               result->ndim = 1;
+               *((int *) ARR_DIMS(result)) = nelems;
+       }
 
        pointers = (Pointer **)ARR_DATA_PTR(result);
        pointers[nelems-1] = (Pointer *)geom;
 
+       /* Go back to previous memory context */
+       MemoryContextSwitchTo(oldcontext);
+
+
        PG_RETURN_ARRAYTYPE_P(result);
 
 }
@@ -326,11 +340,15 @@ Datum unite_finalfunc(PG_FUNCTION_ARGS)
        ArrayType *array;
        int is3d = 0;
        int nelems, i;
-       static int call=1;
        GEOMETRY **geoms, *result, *pgis_geom;
        Geometry *g1, *g2, *geos_result;
+#ifdef DEBUG
+       static int call=1;
+#endif
 
+#ifdef DEBUG
        call++;
+#endif
 
        array = (ArrayType *) PG_GETARG_ARRAYTYPE_P(0);
 
@@ -362,7 +380,11 @@ Datum unite_finalfunc(PG_FUNCTION_ARGS)
                 */
                pfree(pgis_geom);
 
-               elog(NOTICE, "unite_finalfunc(%d): adding geom %d to union", i, call);
+#ifdef DEBUG
+               elog(NOTICE, "unite_finalfunc(%d): adding geom %d to union",
+                               call, i);
+#endif
+
                g2 = GEOSUnion(g1,geos_result);
                if ( g2 == NULL )
                {