libDBI sqlite3 sequence number test

check_sqlite3_seq.c

/*
 * Compile as:
 *
 *  gcc -o check_sqlite3_seq check_sqlite3_seq.c -ldbi
 */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <assert.h>
#include <dbi/dbi.h>

#define DBNAME "debug.sql"
#define DBDIR  "/tmp/"
#define FULLPATH DBDIR DBNAME

/**
 * query callback type
 */
typedef int (*callback)(void *, dbi_result);

/**
 * wrapper for query execution
 */
void query(dbi_conn dbi, char *query, callback cb, void *cb_arg, int exit_code) {
	/*
	 * connect
	 */
	if (!dbi_conn_ping(dbi) && dbi_conn_connect(dbi) < 0) {
		int error = dbi_conn_error(dbi, NULL);
		fprintf(stderr, "Could not connect to DB: error %d\n", error);
		exit(1);
	}
	
	fprintf(stderr, " ---> QUERY: [%s]\n", query);
	dbi_result result = dbi_conn_query(dbi, query);

	if (!result) {
		const char *errmsg = NULL;
		dbi_conn_error(dbi, &errmsg);
		fprintf(stderr, "Error with query [%s]: %s\n", query, errmsg);
		exit(exit_code);
	}

	if (cb) { while (dbi_result_next_row(result)) { cb(cb_arg, result); } }
}

/**
 * callback called to return integer values
 */
int return_integer(void *return_integer, dbi_result result) {
	uint32_t *buffer = (uint32_t *) return_integer;
	*buffer = 0;

	unsigned int type = dbi_result_get_field_type_idx(result, 1);
	if (type == DBI_TYPE_INTEGER) {
		unsigned int size = dbi_result_get_field_attribs_idx(result, 1);
		unsigned int is_unsigned = size & DBI_INTEGER_UNSIGNED;
		size = size & DBI_INTEGER_SIZEMASK;
		switch (size) {
			case DBI_INTEGER_SIZE8:
				if (is_unsigned)
					*buffer = dbi_result_get_ulonglong_idx(result, 1);
				else
					*buffer = dbi_result_get_longlong_idx(result, 1);
				break;
			case DBI_INTEGER_SIZE4:
			case DBI_INTEGER_SIZE3:
				if (is_unsigned)
					*buffer = dbi_result_get_uint_idx(result, 1);
				else
					*buffer = dbi_result_get_int_idx(result, 1);
				break;
			case DBI_INTEGER_SIZE2:
				if (is_unsigned)
					*buffer = dbi_result_get_ushort_idx(result, 1);
				else
					*buffer = dbi_result_get_short_idx(result, 1);
				break;
			case DBI_INTEGER_SIZE1:
				if (is_unsigned)
					*buffer = dbi_result_get_uchar_idx(result, 1);
				else
					*buffer = dbi_result_get_char_idx(result, 1);
				break;
		}
		fprintf(stderr, " <--- callback got a integer field [%d]\n", *buffer);
	} else if (type == DBI_TYPE_DECIMAL) {
		fprintf(stderr, " <--- callback got a decimal field\n");
		return (0);
	} else if (type == DBI_TYPE_STRING) {
		const char *int_string = dbi_result_get_string_idx(result, 1);
		*buffer = atoi(int_string);
		fprintf(stderr, " <--- callback got a ___STRING___ field: \"%s\"\n", int_string);
	} else {
		fprintf(stderr, " <--- callback got an unknown type");
		exit(255);
	}

	// fprintf(stdout, "Returning integer: [%d]\n", *buffer);
	return (0);
}

int main(int argc, char *argv[]) {
	/*
	 * delete previous instance of the DB
	 */
	unlink(FULLPATH);

	/*
	 * initialize 
	 */
	dbi_inst instance;
	if (dbi_initialize_r(NULL, &instance) == -1) {
		fprintf(stderr, "Error: no driver loaded!\n");
		exit(1);
	}
	
	/*
	 * create a new connection object and set the DB name and location
	 */
	dbi_conn dbi = dbi_conn_new_r("sqlite3", instance);
	dbi_conn_set_option(dbi, "dbname", "debug.sql");
	dbi_conn_set_option(dbi, "sqlite3_dbdir", "/tmp/");
	
	/*
	 * create the DB schema
	 */
	query(dbi,
		"create table if not exists objects (\n"
			"\tinode integer primary key autoincrement not null, \n"
			"\tobjectname text(255) not null, \n"
			"\tlast_autotag timestamp not null default current_timestamp, \n"
			"\tchecksum text(40) not null default '', \n"
			"\tsymlink text(1024) not null default '')",
		NULL, NULL, 2);
	
	/*
	 * insert a row
	 */
	query(dbi, "insert into objects (objectname) values ('testname1'), ('testname2'), ('testname3')", NULL, NULL, 3);
	
	/*
	 * fetch the last sequence number
	 */
	int rowid = 0;
	query(dbi, "select last_insert_rowid()", return_integer, &rowid, 4);
	assert(rowid == 3);

	/*
	 * fetch the last sequence number as integer
	 */
	rowid = 0;
	query(dbi, "select cast(last_insert_rowid() as int)", return_integer, &rowid, 5);
	assert(rowid == 3);

	fprintf(stdout, "Last inserted sequence number is %d\n", rowid);
	return (0);
}

The returned value 3 is right, but the callback function receives it as a string, which is wrong even in the first case, but explicitly in the second one, where last_insert_rowid() is cast to int.