src/interfaces/ecpg/ecpglib/descriptor.c

/* dynamic SQL support routines
 *
 * src/interfaces/ecpg/ecpglib/descriptor.c
 */

#define POSTGRES_ECPG_INTERNAL
#include "postgres_fe.h"

#include "catalog/pg_type_d.h"
#include "ecpg-pthread-win32.h"
#include "ecpgerrno.h"
#include "ecpglib.h"
#include "ecpglib_extern.h"
#include "ecpgtype.h"
#include "sql3types.h"
#include "sqlca.h"
#include "sqlda.h"
#include "common/mdb_locale.h"


static void descriptor_free(struct descriptor *desc);

/* We manage descriptors separately for each thread. */
#ifdef ENABLE_THREAD_SAFETY
static pthread_key_t descriptor_key;
static pthread_once_t descriptor_once = PTHREAD_ONCE_INIT;

static void descriptor_deallocate_all(struct descriptor *list);

static void
descriptor_destructor(void *arg)
{
	descriptor_deallocate_all(arg);
}

static void
descriptor_key_init(void)
{
	pthread_key_create(&descriptor_key, descriptor_destructor);
}

static struct descriptor *
get_descriptors(void)
{
	pthread_once(&descriptor_once, descriptor_key_init);
	return (struct descriptor *) pthread_getspecific(descriptor_key);
}

static void
set_descriptors(struct descriptor *value)
{
	pthread_setspecific(descriptor_key, value);
}
#else
static struct descriptor *all_descriptors = NULL;

#define get_descriptors()		(all_descriptors)
#define set_descriptors(value)	do { all_descriptors = (value); } while(0)
#endif

/* old internal convenience function that might go away later */
static PGresult *
ecpg_result_by_descriptor(int line, const char *name)
{
	struct descriptor *desc = ecpg_find_desc(line, name);

	if (desc == NULL)
		return NULL;
	return desc->result;
}

static unsigned int
ecpg_dynamic_type_DDT(Oid type)
{
	switch (type)
	{
		case DATEOID:
			return SQL3_DDT_DATE;
		case TIMEOID:
			return SQL3_DDT_TIME;
		case TIMESTAMPOID:
			return SQL3_DDT_TIMESTAMP;
		case TIMESTAMPTZOID:
			return SQL3_DDT_TIMESTAMP_WITH_TIME_ZONE;
		case TIMETZOID:
			return SQL3_DDT_TIME_WITH_TIME_ZONE;
		default:
			return SQL3_DDT_ILLEGAL;
	}
}

bool
ECPGget_desc_header(int lineno, const char *desc_name, int *count)
{
	PGresult   *ECPGresult;
	struct sqlca_t *sqlca = ECPGget_sqlca();

	if (sqlca == NULL)
	{
		ecpg_raise(lineno, ECPG_OUT_OF_MEMORY,
				   ECPG_SQLSTATE_ECPG_OUT_OF_MEMORY, NULL);
		return false;
	}

	ecpg_init_sqlca(sqlca);
	ECPGresult = ecpg_result_by_descriptor(lineno, desc_name);
	if (!ECPGresult)
		return false;

	*count = PQnfields(ECPGresult);
	sqlca->sqlerrd[2] = 1;
	ecpg_log("ECPGget_desc_header: found %d attributes\n", *count);
	return true;
}

static bool
get_int_item(int lineno, void *var, enum ECPGttype vartype, int value)
{
	switch (vartype)
	{
		case ECPGt_short:
			*(short *) var = (short) value;
			break;
		case ECPGt_int:
			*(int *) var = (int) value;
			break;
		case ECPGt_long:
			*(long *) var = (long) value;
			break;
		case ECPGt_unsigned_short:
			*(unsigned short *) var = (unsigned short) value;
			break;
		case ECPGt_unsigned_int:
			*(unsigned int *) var = (unsigned int) value;
			break;
		case ECPGt_unsigned_long:
			*(unsigned long *) var = (unsigned long) value;
			break;
		case ECPGt_long_long:
			*(long long int *) var = (long long int) value;
			break;
		case ECPGt_unsigned_long_long:
			*(unsigned long long int *) var = (unsigned long long int) value;
			break;
		case ECPGt_float:
			*(float *) var = (float) value;
			break;
		case ECPGt_double:
			*(double *) var = (double) value;
			break;
		default:
			ecpg_raise(lineno, ECPG_VAR_NOT_NUMERIC, ECPG_SQLSTATE_RESTRICTED_DATA_TYPE_ATTRIBUTE_VIOLATION, NULL);
			return false;
	}

	return true;
}

static bool
set_int_item(int lineno, int *target, const void *var, enum ECPGttype vartype)
{
	switch (vartype)
	{
		case ECPGt_short:
			*target = *(const short *) var;
			break;
		case ECPGt_int:
			*target = *(const int *) var;
			break;
		case ECPGt_long:
			*target = *(const long *) var;
			break;
		case ECPGt_unsigned_short:
			*target = *(const unsigned short *) var;
			break;
		case ECPGt_unsigned_int:
			*target = *(const unsigned int *) var;
			break;
		case ECPGt_unsigned_long:
			*target = *(const unsigned long *) var;
			break;
		case ECPGt_long_long:
			*target = *(const long long int *) var;
			break;
		case ECPGt_unsigned_long_long:
			*target = *(const unsigned long long int *) var;
			break;
		case ECPGt_float:
			*target = *(const float *) var;
			break;
		case ECPGt_double:
			*target = *(const double *) var;
			break;
		default:
			ecpg_raise(lineno, ECPG_VAR_NOT_NUMERIC, ECPG_SQLSTATE_RESTRICTED_DATA_TYPE_ATTRIBUTE_VIOLATION, NULL);
			return false;
	}

	return true;
}

static bool
get_char_item(int lineno, void *var, enum ECPGttype vartype, char *value, int varcharsize)
{
	switch (vartype)
	{
		case ECPGt_char:
		case ECPGt_unsigned_char:
		case ECPGt_string:
			strncpy((char *) var, value, varcharsize);
			break;
		case ECPGt_varchar:
			{
				struct ECPGgeneric_varchar *variable =
					(struct ECPGgeneric_varchar *) var;

				if (varcharsize == 0)
					memcpy(variable->arr, value, strlen(value));
				else
					strncpy(variable->arr, value, varcharsize);

				variable->len = strlen(value);
				if (varcharsize > 0 && variable->len > varcharsize)
					variable->len = varcharsize;
			}
			break;
		default:
			ecpg_raise(lineno, ECPG_VAR_NOT_CHAR, ECPG_SQLSTATE_RESTRICTED_DATA_TYPE_ATTRIBUTE_VIOLATION, NULL);
			return false;
	}

	return true;
}

#define RETURN_IF_NO_DATA	if (ntuples < 1) \
				{ \
					va_end(args); \
					ecpg_raise(lineno, ECPG_NOT_FOUND, ECPG_SQLSTATE_NO_DATA, NULL); \
					return false; \
				}

bool
ECPGget_desc(int lineno, const char *desc_name, int index,...)
{
	va_list		args;
	PGresult   *ECPGresult;
	enum ECPGdtype type;
	int			ntuples,
				act_tuple;
	struct variable data_var;
	struct sqlca_t *sqlca = ECPGget_sqlca();

	if (sqlca == NULL)
	{
		ecpg_raise(lineno, ECPG_OUT_OF_MEMORY,
				   ECPG_SQLSTATE_ECPG_OUT_OF_MEMORY, NULL);
		return false;
	}

	va_start(args, index);
	ecpg_init_sqlca(sqlca);
	ECPGresult = ecpg_result_by_descriptor(lineno, desc_name);
	if (!ECPGresult)
	{
		va_end(args);
		return false;
	}

	ntuples = PQntuples(ECPGresult);

	if (index < 1 || index > PQnfields(ECPGresult))
	{
		ecpg_raise(lineno, ECPG_INVALID_DESCRIPTOR_INDEX, ECPG_SQLSTATE_INVALID_DESCRIPTOR_INDEX, NULL);
		va_end(args);
		return false;
	}

	ecpg_log("ECPGget_desc: reading items for tuple %d\n", index);
	--index;

	type = va_arg(args, enum ECPGdtype);

	memset(&data_var, 0, sizeof data_var);
	data_var.type = ECPGt_EORT;
	data_var.ind_type = ECPGt_NO_INDICATOR;

	while (type != ECPGd_EODT)
	{
		char		type_str[20];
		long		varcharsize;
		long		offset;
		long		arrsize;
		enum ECPGttype vartype;
		void	   *var;

		vartype = va_arg(args, enum ECPGttype);
		var = va_arg(args, void *);
		varcharsize = va_arg(args, long);
		arrsize = va_arg(args, long);
		offset = va_arg(args, long);

		switch (type)
		{
			case (ECPGd_indicator):
				RETURN_IF_NO_DATA;
				data_var.ind_type = vartype;
				data_var.ind_pointer = var;
				data_var.ind_varcharsize = varcharsize;
				data_var.ind_arrsize = arrsize;
				data_var.ind_offset = offset;
				if (data_var.ind_arrsize == 0 || data_var.ind_varcharsize == 0)
					data_var.ind_value = *((void **) (data_var.ind_pointer));
				else
					data_var.ind_value = data_var.ind_pointer;
				break;

			case ECPGd_data:
				RETURN_IF_NO_DATA;
				data_var.type = vartype;
				data_var.pointer = var;
				data_var.varcharsize = varcharsize;
				data_var.arrsize = arrsize;
				data_var.offset = offset;
				if (data_var.arrsize == 0 || data_var.varcharsize == 0)
					data_var.value = *((void **) (data_var.pointer));
				else
					data_var.value = data_var.pointer;
				break;

			case ECPGd_name:
				if (!get_char_item(lineno, var, vartype, PQfname(ECPGresult, index), varcharsize))
				{
					va_end(args);
					return false;
				}

				ecpg_log("ECPGget_desc: NAME = %s\n", PQfname(ECPGresult, index));
				break;

			case ECPGd_nullable:
				if (!get_int_item(lineno, var, vartype, 1))
				{
					va_end(args);
					return false;
				}

				break;

			case ECPGd_key_member:
				if (!get_int_item(lineno, var, vartype, 0))
				{
					va_end(args);
					return false;
				}

				break;

			case ECPGd_scale:
				if (!get_int_item(lineno, var, vartype, (PQfmod(ECPGresult, index) - VARHDRSZ) & 0xffff))
				{
					va_end(args);
					return false;
				}

				ecpg_log("ECPGget_desc: SCALE = %d\n", (PQfmod(ECPGresult, index) - VARHDRSZ) & 0xffff);
				break;

			case ECPGd_precision:
				if (!get_int_item(lineno, var, vartype, PQfmod(ECPGresult, index) >> 16))
				{
					va_end(args);
					return false;
				}

				ecpg_log("ECPGget_desc: PRECISION = %d\n", PQfmod(ECPGresult, index) >> 16);
				break;

			case ECPGd_octet:
				if (!get_int_item(lineno, var, vartype, PQfsize(ECPGresult, index)))
				{
					va_end(args);
					return false;
				}

				ecpg_log("ECPGget_desc: OCTET_LENGTH = %d\n", PQfsize(ECPGresult, index));
				break;

			case ECPGd_length:
				if (!get_int_item(lineno, var, vartype, PQfmod(ECPGresult, index) - VARHDRSZ))
				{
					va_end(args);
					return false;
				}

				ecpg_log("ECPGget_desc: LENGTH = %d\n", PQfmod(ECPGresult, index) - VARHDRSZ);
				break;

			case ECPGd_type:
				if (!get_int_item(lineno, var, vartype, ecpg_dynamic_type(PQftype(ECPGresult, index))))
				{
					va_end(args);
					return false;
				}

				ecpg_log("ECPGget_desc: TYPE = %d\n", ecpg_dynamic_type(PQftype(ECPGresult, index)));
				break;

			case ECPGd_di_code:
				if (!get_int_item(lineno, var, vartype, ecpg_dynamic_type_DDT(PQftype(ECPGresult, index))))
				{
					va_end(args);
					return false;
				}

				ecpg_log("ECPGget_desc: TYPE = %d\n", ecpg_dynamic_type_DDT(PQftype(ECPGresult, index)));
				break;

			case ECPGd_cardinality:
				if (!get_int_item(lineno, var, vartype, PQntuples(ECPGresult)))
				{
					va_end(args);
					return false;
				}

				ecpg_log("ECPGget_desc: CARDINALITY = %d\n", PQntuples(ECPGresult));
				break;

			case ECPGd_ret_length:
			case ECPGd_ret_octet:

				RETURN_IF_NO_DATA;

				/*
				 * this is like ECPGstore_result
				 */
				if (arrsize > 0 && ntuples > arrsize)
				{
					ecpg_log("ECPGget_desc on line %d: incorrect number of matches; %d don't fit into array of %ld\n",
							 lineno, ntuples, arrsize);
					ecpg_raise(lineno, ECPG_TOO_MANY_MATCHES, ECPG_SQLSTATE_CARDINALITY_VIOLATION, NULL);
					va_end(args);
					return false;
				}
				/* allocate storage if needed */
				if (arrsize == 0 && *(void **) var == NULL)
				{
					void	   *mem = (void *) ecpg_auto_alloc(offset * ntuples, lineno);

					if (!mem)
					{
						va_end(args);
						return false;
					}
					*(void **) var = mem;
					var = mem;
				}

				for (act_tuple = 0; act_tuple < ntuples; act_tuple++)
				{
					if (!get_int_item(lineno, var, vartype, PQgetlength(ECPGresult, act_tuple, index)))
					{
						va_end(args);
						return false;
					}
					var = (char *) var + offset;
					ecpg_log("ECPGget_desc: RETURNED[%d] = %d\n", act_tuple, PQgetlength(ECPGresult, act_tuple, index));
				}
				break;

			default:
				snprintf(type_str, sizeof(type_str), "%d", type);
				ecpg_raise(lineno, ECPG_UNKNOWN_DESCRIPTOR_ITEM, ECPG_SQLSTATE_ECPG_INTERNAL_ERROR, type_str);
				va_end(args);
				return false;
		}

		type = va_arg(args, enum ECPGdtype);
	}

	if (data_var.type != ECPGt_EORT)
	{
		struct statement stmt;

		memset(&stmt, 0, sizeof stmt);
		stmt.lineno = lineno;

		/* Make sure we do NOT honor the locale for numeric input */
		/* since the database gives the standard decimal point */
		/* (see comments in execute.c) */
#ifdef HAVE_USELOCALE

		/*
		 * To get here, the above PQnfields() test must have found nonzero
		 * fields.  One needs a connection to create such a descriptor.  (EXEC
		 * SQL SET DESCRIPTOR can populate the descriptor's "items", but it
		 * can't change the descriptor's PQnfields().)  Any successful
		 * connection initializes ecpg_clocale.
		 */
		Assert(ecpg_clocale);
		stmt.oldlocale = uselocale(ecpg_clocale);
#else
#ifdef HAVE__CONFIGTHREADLOCALE
		stmt.oldthreadlocale = _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
#endif
		stmt.oldlocale = ecpg_strdup(SETLOCALE(LC_NUMERIC, NULL), lineno);
		SETLOCALE(LC_NUMERIC, "C");
#endif

		/* desperate try to guess something sensible */
		stmt.connection = ecpg_get_connection(NULL);
		ecpg_store_result(ECPGresult, index, &stmt, &data_var);

#ifdef HAVE_USELOCALE
		if (stmt.oldlocale != (locale_t) 0)
			uselocale(stmt.oldlocale);
#else
		if (stmt.oldlocale)
		{
			SETLOCALE(LC_NUMERIC, stmt.oldlocale);
			ecpg_free(stmt.oldlocale);
		}
#ifdef HAVE__CONFIGTHREADLOCALE
		if (stmt.oldthreadlocale != -1)
			(void) _configthreadlocale(stmt.oldthreadlocale);
#endif
#endif
	}
	else if (data_var.ind_type != ECPGt_NO_INDICATOR && data_var.ind_pointer != NULL)

		/*
		 * ind_type != NO_INDICATOR should always have ind_pointer != NULL but
		 * since this might be changed manually in the .c file let's play it
		 * safe
		 */
	{
		/*
		 * this is like ECPGstore_result but since we don't have a data
		 * variable at hand, we can't call it
		 */
		if (data_var.ind_arrsize > 0 && ntuples > data_var.ind_arrsize)
		{
			ecpg_log("ECPGget_desc on line %d: incorrect number of matches (indicator); %d don't fit into array of %ld\n",
					 lineno, ntuples, data_var.ind_arrsize);
			ecpg_raise(lineno, ECPG_TOO_MANY_MATCHES, ECPG_SQLSTATE_CARDINALITY_VIOLATION, NULL);
			va_end(args);
			return false;
		}

		/* allocate storage if needed */
		if (data_var.ind_arrsize == 0 && data_var.ind_value == NULL)
		{
			void	   *mem = (void *) ecpg_auto_alloc(data_var.ind_offset * ntuples, lineno);

			if (!mem)
			{
				va_end(args);
				return false;
			}
			*(void **) data_var.ind_pointer = mem;
			data_var.ind_value = mem;
		}

		for (act_tuple = 0; act_tuple < ntuples; act_tuple++)
		{
			if (!get_int_item(lineno, data_var.ind_value, data_var.ind_type, -PQgetisnull(ECPGresult, act_tuple, index)))
			{
				va_end(args);
				return false;
			}
			data_var.ind_value = (char *) data_var.ind_value + data_var.ind_offset;
			ecpg_log("ECPGget_desc: INDICATOR[%d] = %d\n", act_tuple, -PQgetisnull(ECPGresult, act_tuple, index));
		}
	}
	sqlca->sqlerrd[2] = ntuples;
	va_end(args);
	return true;
}

#undef RETURN_IF_NO_DATA

bool
ECPGset_desc_header(int lineno, const char *desc_name, int count)
{
	struct descriptor *desc = ecpg_find_desc(lineno, desc_name);

	if (desc == NULL)
		return false;
	desc->count = count;
	return true;
}

static void
set_desc_attr(struct descriptor_item *desc_item, struct variable *var,
			  char *tobeinserted)
{
	if (var->type != ECPGt_bytea)
		desc_item->is_binary = false;

	else
	{
		struct ECPGgeneric_bytea *variable =
			(struct ECPGgeneric_bytea *) (var->value);

		desc_item->is_binary = true;
		desc_item->data_len = variable->len;
	}

	ecpg_free(desc_item->data); /* free() takes care of a potential NULL value */
	desc_item->data = (char *) tobeinserted;
}


bool
ECPGset_desc(int lineno, const char *desc_name, int index,...)
{
	va_list		args;
	struct descriptor *desc;
	struct descriptor_item *desc_item;
	struct variable *var;

	desc = ecpg_find_desc(lineno, desc_name);
	if (desc == NULL)
		return false;

	for (desc_item = desc->items; desc_item; desc_item = desc_item->next)
	{
		if (desc_item->num == index)
			break;
	}

	if (desc_item == NULL)
	{
		desc_item = (struct descriptor_item *) ecpg_alloc(sizeof(*desc_item), lineno);
		if (!desc_item)
			return false;
		desc_item->num = index;
		if (desc->count < index)
			desc->count = index;
		desc_item->next = desc->items;
		desc->items = desc_item;
	}

	if (!(var = (struct variable *) ecpg_alloc(sizeof(struct variable), lineno)))
		return false;

	va_start(args, index);

	for (;;)
	{
		enum ECPGdtype itemtype;
		char	   *tobeinserted = NULL;

		itemtype = va_arg(args, enum ECPGdtype);

		if (itemtype == ECPGd_EODT)
			break;

		var->type = va_arg(args, enum ECPGttype);
		var->pointer = va_arg(args, char *);

		var->varcharsize = va_arg(args, long);
		var->arrsize = va_arg(args, long);
		var->offset = va_arg(args, long);

		if (var->arrsize == 0 || var->varcharsize == 0)
			var->value = *((char **) (var->pointer));
		else
			var->value = var->pointer;

		/*
		 * negative values are used to indicate an array without given bounds
		 */
		/* reset to zero for us */
		if (var->arrsize < 0)
			var->arrsize = 0;
		if (var->varcharsize < 0)
			var->varcharsize = 0;

		var->next = NULL;

		switch (itemtype)
		{
			case ECPGd_data:
				{
					if (!ecpg_store_input(lineno, true, var, &tobeinserted, false))
					{
						ecpg_free(var);
						va_end(args);
						return false;
					}

					set_desc_attr(desc_item, var, tobeinserted);
					tobeinserted = NULL;
					break;
				}

			case ECPGd_indicator:
				set_int_item(lineno, &desc_item->indicator, var->pointer, var->type);
				break;

			case ECPGd_length:
				set_int_item(lineno, &desc_item->length, var->pointer, var->type);
				break;

			case ECPGd_precision:
				set_int_item(lineno, &desc_item->precision, var->pointer, var->type);
				break;

			case ECPGd_scale:
				set_int_item(lineno, &desc_item->scale, var->pointer, var->type);
				break;

			case ECPGd_type:
				set_int_item(lineno, &desc_item->type, var->pointer, var->type);
				break;

			default:
				{
					char		type_str[20];

					snprintf(type_str, sizeof(type_str), "%d", itemtype);
					ecpg_raise(lineno, ECPG_UNKNOWN_DESCRIPTOR_ITEM, ECPG_SQLSTATE_ECPG_INTERNAL_ERROR, type_str);
					ecpg_free(var);
					va_end(args);
					return false;
				}
		}
	}
	ecpg_free(var);
	va_end(args);

	return true;
}

/* Free the descriptor and items in it. */
static void
descriptor_free(struct descriptor *desc)
{
	struct descriptor_item *desc_item;

	for (desc_item = desc->items; desc_item;)
	{
		struct descriptor_item *di;

		ecpg_free(desc_item->data);
		di = desc_item;
		desc_item = desc_item->next;
		ecpg_free(di);
	}

	ecpg_free(desc->name);
	PQclear(desc->result);
	ecpg_free(desc);
}

bool
ECPGdeallocate_desc(int line, const char *name)
{
	struct descriptor *desc;
	struct descriptor *prev;
	struct sqlca_t *sqlca = ECPGget_sqlca();

	if (sqlca == NULL)
	{
		ecpg_raise(line, ECPG_OUT_OF_MEMORY,
				   ECPG_SQLSTATE_ECPG_OUT_OF_MEMORY, NULL);
		return false;
	}

	ecpg_init_sqlca(sqlca);
	for (desc = get_descriptors(), prev = NULL; desc; prev = desc, desc = desc->next)
	{
		if (strcmp(name, desc->name) == 0)
		{
			if (prev)
				prev->next = desc->next;
			else
				set_descriptors(desc->next);
			descriptor_free(desc);
			return true;
		}
	}
	ecpg_raise(line, ECPG_UNKNOWN_DESCRIPTOR, ECPG_SQLSTATE_INVALID_SQL_DESCRIPTOR_NAME, name);
	return false;
}

#ifdef ENABLE_THREAD_SAFETY

/* Deallocate all descriptors in the list */
static void
descriptor_deallocate_all(struct descriptor *list)
{
	while (list)
	{
		struct descriptor *next = list->next;

		descriptor_free(list);
		list = next;
	}
}
#endif							/* ENABLE_THREAD_SAFETY */

bool
ECPGallocate_desc(int line, const char *name)
{
	struct descriptor *new;
	struct sqlca_t *sqlca = ECPGget_sqlca();

	if (sqlca == NULL)
	{
		ecpg_raise(line, ECPG_OUT_OF_MEMORY,
				   ECPG_SQLSTATE_ECPG_OUT_OF_MEMORY, NULL);
		return false;
	}

	ecpg_init_sqlca(sqlca);
	new = (struct descriptor *) ecpg_alloc(sizeof(struct descriptor), line);
	if (!new)
		return false;
	new->next = get_descriptors();
	new->name = ecpg_alloc(strlen(name) + 1, line);
	if (!new->name)
	{
		ecpg_free(new);
		return false;
	}
	new->count = -1;
	new->items = NULL;
	new->result = PQmakeEmptyPGresult(NULL, 0);
	if (!new->result)
	{
		ecpg_free(new->name);
		ecpg_free(new);
		ecpg_raise(line, ECPG_OUT_OF_MEMORY, ECPG_SQLSTATE_ECPG_OUT_OF_MEMORY, NULL);
		return false;
	}
	strcpy(new->name, name);
	set_descriptors(new);
	return true;
}

/* Find descriptor with name in the connection. */
struct descriptor *
ecpg_find_desc(int line, const char *name)
{
	struct descriptor *desc;

	for (desc = get_descriptors(); desc; desc = desc->next)
	{
		if (strcmp(name, desc->name) == 0)
			return desc;
	}

	ecpg_raise(line, ECPG_UNKNOWN_DESCRIPTOR, ECPG_SQLSTATE_INVALID_SQL_DESCRIPTOR_NAME, name);
	return NULL;				/* not found */
}

bool
ECPGdescribe(int line, int compat, bool input, const char *connection_name, const char *stmt_name,...)
{
	bool		ret = false;
	struct connection *con;
	struct prepared_statement *prep;
	PGresult   *res;
	va_list		args;

	/* DESCRIBE INPUT is not yet supported */
	if (input)
	{
		ecpg_raise(line, ECPG_UNSUPPORTED, ECPG_SQLSTATE_ECPG_INTERNAL_ERROR, "DESCRIBE INPUT");
		return ret;
	}

	con = ecpg_get_connection(connection_name);
	if (!con)
	{
		ecpg_raise(line, ECPG_NO_CONN, ECPG_SQLSTATE_CONNECTION_DOES_NOT_EXIST,
				   connection_name ? connection_name : ecpg_gettext("NULL"));
		return ret;
	}
	prep = ecpg_find_prepared_statement(stmt_name, con, NULL);
	if (!prep)
	{
		ecpg_raise(line, ECPG_INVALID_STMT, ECPG_SQLSTATE_INVALID_SQL_STATEMENT_NAME, stmt_name);
		return ret;
	}

	va_start(args, stmt_name);

	for (;;)
	{
		enum ECPGttype type;
		void	   *ptr;

		/* variable type */
		type = va_arg(args, enum ECPGttype);

		if (type == ECPGt_EORT)
			break;

		/* rest of variable parameters */
		ptr = va_arg(args, void *);
		(void) va_arg(args, long);	/* skip args */
		(void) va_arg(args, long);
		(void) va_arg(args, long);

		/* variable indicator */
		(void) va_arg(args, enum ECPGttype);
		(void) va_arg(args, void *);	/* skip args */
		(void) va_arg(args, long);
		(void) va_arg(args, long);
		(void) va_arg(args, long);

		switch (type)
		{
			case ECPGt_descriptor:
				{
					char	   *name = ptr;
					struct descriptor *desc = ecpg_find_desc(line, name);

					if (desc == NULL)
						break;

					res = PQdescribePrepared(con->connection, stmt_name);
					if (!ecpg_check_PQresult(res, line, con->connection, compat))
						break;

					PQclear(desc->result);

					desc->result = res;
					ret = true;
					break;
				}
			case ECPGt_sqlda:
				{
					if (INFORMIX_MODE(compat))
					{
						struct sqlda_compat **_sqlda = ptr;
						struct sqlda_compat *sqlda;

						res = PQdescribePrepared(con->connection, stmt_name);
						if (!ecpg_check_PQresult(res, line, con->connection, compat))
							break;

						sqlda = ecpg_build_compat_sqlda(line, res, -1, compat);
						if (sqlda)
						{
							struct sqlda_compat *sqlda_old = *_sqlda;
							struct sqlda_compat *sqlda_old1;

							while (sqlda_old)
							{
								sqlda_old1 = sqlda_old->desc_next;
								free(sqlda_old);
								sqlda_old = sqlda_old1;
							}

							*_sqlda = sqlda;
							ret = true;
						}

						PQclear(res);
					}
					else
					{
						struct sqlda_struct **_sqlda = ptr;
						struct sqlda_struct *sqlda;

						res = PQdescribePrepared(con->connection, stmt_name);
						if (!ecpg_check_PQresult(res, line, con->connection, compat))
							break;

						sqlda = ecpg_build_native_sqlda(line, res, -1, compat);
						if (sqlda)
						{
							struct sqlda_struct *sqlda_old = *_sqlda;
							struct sqlda_struct *sqlda_old1;

							while (sqlda_old)
							{
								sqlda_old1 = sqlda_old->desc_next;
								free(sqlda_old);
								sqlda_old = sqlda_old1;
							}

							*_sqlda = sqlda;
							ret = true;
						}

						PQclear(res);
					}
					break;
				}
			default:
				/* nothing else may come */
				;
		}
	}

	va_end(args);

	return ret;
}