/*
 * libdbi - database independent abstraction layer for C.
 * Copyright (C) 2001-2003, David Parker and Mark Tobenkin.
 * http://libdbi.sourceforge.net
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * $Id: dbi_main.c,v 1.75 2006/06/02 17:18:16 qu1j0t3 Exp $
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#define _GNU_SOURCE /* since we need the asprintf() prototype */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>

/* Dlopen stuff */
#if HAVE_LTDL_H
#include <ltdl.h>
#define my_dlopen(foo,bar) lt_dlopen(foo)
#define my_dlsym lt_dlsym
#define my_dlclose lt_dlclose
#define my_dlerror lt_dlerror

#elif HAVE_MACH_O_DYLD_H
#include <mach-o/dyld.h>
static void * dyld_dlopen(const char * file);
static void * dyld_dlsym(void * hand, const char * name);
static int dyld_dlclose(void * hand);
static const char * dyld_dlerror();
#define my_dlopen(foo,bar) dyld_dlopen(foo)
#define my_dlsym dyld_dlsym
#define my_dlerror dyld_dlerror
#define my_dlclose dyld_dlclose

#elif __MINGW32__
#include <windows.h>
void *win_dlopen(const char*, int);
void *win_dlsym(void *, const char*);
int win_dlclose(void *);
char *win_dlerror();
/* just for compiling support,if anyone has used these masks in code. The MODE argument to `dlopen' contains one of the following: */
#define RTLD_LAZY       0x001   /* Lazy function call binding.  */
#define RTLD_NOW        0x002   /* Immediate function call binding.  */
#define RTLD_BINDING_MASK 0x003   /* Mask of binding time value.  */
#define my_dlopen(foo,bar) win_dlopen(foo,bar)
#define my_dlsym win_dlsym
#define my_dlclose win_dlclose
#define my_dlerror win_dlerror

#elif HAVE_DLFCN_H
#include <dlfcn.h>
#define my_dlopen dlopen
#define my_dlsym dlsym
#define my_dlclose dlclose
#define my_dlerror dlerror

#else
#error no dynamic loading support
#endif
/* end dlopen stuff */

#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>

#include <math.h>
#include <limits.h>

#include <dbi/dbi.h>
#include <dbi/dbi-dev.h>

#ifdef __MINGW32__
#  define DBI_PATH_SEPARATOR "\\"
#  ifndef DBI_DRIVER_DIR
#	define DBI_DRIVER_DIR "c:\\libdbi\\lib\\dbd" /* use this as the default */
#  endif
#  else
#    define DBI_PATH_SEPARATOR "/"
#    ifndef DBI_DRIVER_DIR
#    	define DBI_DRIVER_DIR "/usr/local/lib/dbd" /* use this as the default */
#    endif
#endif

#ifndef DLSYM_PREFIX
#define DLSYM_PREFIX ""
#endif

/* declarations of optional external functions */
#ifndef HAVE_VASPRINTF
int int_vasprintf(char **result, const char *format, va_list *args);
int vasprintf(char **result, const char *format, va_list args);
#endif
#ifndef HAVE_ASPRINTF
int asprintf(char **result, const char *format, ...);
#endif

/* declarations for internal functions -- anything declared as static won't be accessible by name from client programs */
static dbi_driver_t *_get_driver(const char *filename);
static void _free_custom_functions(dbi_driver_t *driver);
static dbi_option_t *_find_or_create_option_node(dbi_conn Conn, const char *key);
static int _update_internal_conn_list(dbi_conn_t *conn, int operation);
static void _free_caps(_capability_t *caproot);
static const char *_get_option(dbi_conn Conn, const char *key, int aggressive);
static int _get_option_numeric(dbi_conn Conn, const char *key, int aggressive);
static unsigned int _parse_versioninfo(const char *version);

void _error_handler(dbi_conn_t *conn, dbi_error_flag errflag);
extern int _disjoin_from_conn(dbi_result_t *result);

dbi_result dbi_conn_queryf(dbi_conn Conn, const char *formatstr, ...) __attribute__ ((format (printf, 2, 3)));
int dbi_conn_set_error(dbi_conn Conn, int errnum, const char *formatstr, ...) __attribute__ ((format (printf, 3, 4)));

/* must not be called "ERROR" due to a name clash on Windoze */
static const char *my_ERROR = "ERROR";
static dbi_driver_t *rootdriver;
static dbi_conn_t *rootconn;
int dbi_verbosity = 1;

/* XXX DBI CORE FUNCTIONS XXX */

int dbi_initialize(const char *driverdir) {
	DIR *dir;
	struct dirent *driver_dirent = NULL;
	struct stat statbuf;
	char fullpath[FILENAME_MAX];
	char *effective_driverdir;
	
	int num_loaded = 0;
	dbi_driver_t *driver = NULL;
	dbi_driver_t *prevdriver = NULL;
#if HAVE_LTDL_H
        (void)lt_dlinit();
#endif	
	rootdriver = NULL;
	effective_driverdir = (driverdir ? (char *)driverdir : DBI_DRIVER_DIR);
	dir = opendir(effective_driverdir);

	if (dir == NULL) {
		return -1;
	}
	else {
		while ((driver_dirent = readdir(dir)) != NULL) {
			driver = NULL;
			snprintf(fullpath, FILENAME_MAX, "%s%s%s", effective_driverdir, DBI_PATH_SEPARATOR, driver_dirent->d_name);
			if ((stat(fullpath, &statbuf) == 0) && S_ISREG(statbuf.st_mode) && strrchr(driver_dirent->d_name, '.') && (!strcmp(strrchr(driver_dirent->d_name, '.'), DRIVER_EXT))) {
				/* file is a stat'able regular file that ends in .so (or appropriate dynamic library extension) */
				driver = _get_driver(fullpath);
				if (driver && (driver->functions->initialize(driver) != -1)) {
					if (!rootdriver) {
						rootdriver = driver;
					}
					if (prevdriver) {
						prevdriver->next = driver;
					}
					prevdriver = driver;
					num_loaded++;
				}
				else {
					if (driver && driver->dlhandle) my_dlclose(driver->dlhandle);
					if (driver && driver->functions) free(driver->functions);
					if (driver) free(driver);
					driver = NULL; /* don't include in linked list */
					if (dbi_verbosity) fprintf(stderr, "libdbi: Failed to load driver: %s\n", fullpath);
				}
			}
		}
		closedir(dir);
	}
	
	return num_loaded;
}

void dbi_shutdown() {
	dbi_conn_t *curconn = rootconn;
	dbi_conn_t *nextconn;
	
	dbi_driver_t *curdriver = rootdriver;
	dbi_driver_t *nextdriver;
	
	while (curconn) {
		nextconn = curconn->next;
		dbi_conn_close((dbi_conn)curconn);
		curconn = nextconn;
	}
	
	while (curdriver) {
		nextdriver = curdriver->next;
		my_dlclose(curdriver->dlhandle);
		free(curdriver->functions);
		_free_custom_functions(curdriver);
		_free_caps(curdriver->caps);
		free(curdriver->filename);
		free(curdriver);
		curdriver = nextdriver;
	}
#if HAVE_LTDL_H
        (void)lt_dlexit();
#endif	
	rootdriver = NULL;
}

const char *dbi_version() {
	return "libdbi v" VERSION;
}

int dbi_set_verbosity(int verbosity) {
	/* whether or not to spew stderr messages when something bad happens (and
	 * isn't handled through the normal connection-oriented DBI error
	 * mechanisms) */

	int prev = dbi_verbosity;
	dbi_verbosity = verbosity;
	return prev;
}

/* XXX DRIVER FUNCTIONS XXX */

dbi_driver dbi_driver_list(dbi_driver Current) {
	dbi_driver_t *current = Current;

	if (current == NULL) {
		return (dbi_driver)rootdriver;
	}

	return (dbi_driver)current->next;
}

dbi_driver dbi_driver_open(const char *name) {
	dbi_driver_t *driver = rootdriver;

	while (driver && strcasecmp(name, driver->info->name)) {
		driver = driver->next;
	}

	return driver;
}

int dbi_driver_is_reserved_word(dbi_driver Driver, const char *word) {
	unsigned int idx = 0;
	dbi_driver_t *driver = Driver;
	
	if (!driver) return 0;
	
	while (driver->reserved_words[idx]) {
		if (strcasecmp(word, driver->reserved_words[idx]) == 0) {
			return 1;
		}
		idx++;
	}
	return 0;
}

void *dbi_driver_specific_function(dbi_driver Driver, const char *name) {
	dbi_driver_t *driver = Driver;
	dbi_custom_function_t *custom;

	if (!driver) return NULL;

	custom = driver->custom_functions;
	
	while (custom && strcasecmp(name, custom->name)) {
		custom = custom->next;
	}

	return custom ? custom->function_pointer : NULL;
}

int dbi_driver_cap_get(dbi_driver Driver, const char *capname) {
	dbi_driver_t *driver = Driver;
	_capability_t *cap;

	if (!driver) return 0;

	cap = driver->caps;

	while (cap && strcmp(capname, cap->name)) {
		cap = cap->next;
	}

	return cap ? cap->value : 0;
}

int dbi_conn_cap_get(dbi_conn Conn, const char *capname) {
	dbi_conn_t *conn = Conn;
	_capability_t *cap;

	if (!conn) return 0;

	cap = conn->caps;
	
	while (cap && strcmp(capname, cap->name)) {
		cap = cap->next;
	}

	return cap ? cap->value : dbi_driver_cap_get((dbi_driver)conn->driver, capname);
}

/* DRIVER: informational functions */

const char *dbi_driver_get_name(dbi_driver Driver) {
	dbi_driver_t *driver = Driver;
	
	if (!driver) return my_ERROR;
	
	return driver->info->name;
}

const char *dbi_driver_get_filename(dbi_driver Driver) {
	dbi_driver_t *driver = Driver;
	
	if (!driver) return my_ERROR;
	
	return driver->filename;
}

const char *dbi_driver_get_description(dbi_driver Driver) {
	dbi_driver_t *driver = Driver;
	
	if (!driver) return my_ERROR;
	
	return driver->info->description;
}

const char *dbi_driver_get_maintainer(dbi_driver Driver) {
	dbi_driver_t *driver = Driver;
	
	if (!driver) return my_ERROR;

	return driver->info->maintainer;
}

const char *dbi_driver_get_url(dbi_driver Driver) {
	dbi_driver_t *driver = Driver;

	if (!driver) return my_ERROR;

	return driver->info->url;
}

const char *dbi_driver_get_version(dbi_driver Driver) {
	dbi_driver_t *driver = Driver;
	
	if (!driver) return my_ERROR;
	
	return driver->info->version;
}

const char *dbi_driver_get_date_compiled(dbi_driver Driver) {
	dbi_driver_t *driver = Driver;
	
	if (!driver) return my_ERROR;
	
	return driver->info->date_compiled;
}

size_t dbi_driver_quote_string_copy(dbi_driver Driver, const char *orig, char **newquoted) {
	dbi_driver_t *driver = Driver;
	char *newstr;
	size_t newlen;
	
	if (!driver || !orig || !newquoted) return 0;

	newstr = malloc((strlen(orig)*2)+4+1); /* worst case, we have to escape every character and add 2*2 surrounding quotes */

	if (!newstr) {
		return 0;
	}
	
	newlen = driver->functions->quote_string(driver, orig, newstr);
	if (!newlen) {
		free(newstr);
		return 0;
	}

	*newquoted = newstr;

	return newlen;
}

size_t dbi_driver_quote_string(dbi_driver Driver, char **orig) {
	char *temp = NULL;
	char *newstr = NULL;
	size_t newlen;

	if (!orig || !*orig) {
		return 0;
	}
	
	newlen = dbi_driver_quote_string_copy(Driver, *orig, &newstr);
	if (!newlen) {
	  /* in case of an error, leave the original string alone */
	  return 0;
	}

	temp = *orig;
	*orig = newstr;
	free(temp); /* original unescaped string */

	return newlen;
}

const char* dbi_driver_encoding_from_iana(dbi_driver Driver, const char* iana_encoding) {
  dbi_driver_t *driver = Driver;
	
  if (!driver) {
    return NULL;
  }

  return driver->functions->encoding_from_iana(iana_encoding);
}

const char* dbi_driver_encoding_to_iana(dbi_driver Driver, const char* db_encoding) {
  dbi_driver_t *driver = Driver;
	
  if (!driver) {
    return NULL;
  }

  return driver->functions->encoding_to_iana(db_encoding);
}


/* XXX DRIVER FUNCTIONS XXX */

dbi_conn dbi_conn_new(const char *name) {
	dbi_driver driver;
	dbi_conn conn;

	driver = dbi_driver_open(name);
	conn = dbi_conn_open(driver);

	return conn;
}

dbi_conn dbi_conn_open(dbi_driver Driver) {
	dbi_driver_t *driver = Driver;
	dbi_conn_t *conn;
	
	if (!driver) {
		return NULL;
	}

	conn = malloc(sizeof(dbi_conn_t));
	if (!conn) {
		return NULL;
	}
	conn->driver = driver;
	conn->options = NULL;
	conn->caps = NULL;
	conn->connection = NULL;
	conn->current_db = NULL;
	conn->error_flag = DBI_ERROR_NONE;
	conn->error_number = 0;
	conn->error_message = NULL;
	conn->error_handler = NULL;
	conn->error_handler_argument = NULL;
	_update_internal_conn_list(conn, 1);
	conn->results = NULL;
	conn->results_size = conn->results_used = 0;

	return (dbi_conn)conn;
}

int dbi_conn_disjoin_results(dbi_conn Conn) {
	dbi_conn_t *conn = Conn;
	int errors = 0;
	int idx;

	if (!conn) return 0;

	for (idx = conn->results_used-1; idx >= 0; idx--) {
		if (dbi_result_disjoin((dbi_result)conn->results[idx]) < 0) {
			errors--;
		}
	}

	return errors;
}

void dbi_conn_close(dbi_conn Conn) {
	dbi_conn_t *conn = Conn;
	
	if (!conn) return;
	
	_update_internal_conn_list(conn, -1);
	
	conn->driver->functions->disconnect(conn);
	conn->driver = NULL;
	dbi_conn_clear_options(Conn);
	_free_caps(conn->caps);
	conn->connection = NULL;
	
	if (conn->current_db) free(conn->current_db);
	if (conn->error_message) free(conn->error_message);
	conn->error_number = 0;
	
	conn->error_handler = NULL;
	conn->error_handler_argument = NULL;
	free(conn->results);

	free(conn);

}

dbi_driver dbi_conn_get_driver(dbi_conn Conn) {
	dbi_conn_t *conn = Conn;
	
	if (!conn) return NULL;
	
	return conn->driver;
}

int dbi_conn_error(dbi_conn Conn, const char **errmsg_dest) {
	dbi_conn_t *conn = Conn;
	char number_portion[20];
	static char *errmsg = NULL; // XXX quick hack, revisit this when API is redesigned

	if (errmsg_dest) {
		if (errmsg) free(errmsg);
		
		if (conn->error_number) {
			snprintf(number_portion, 20, "%d: ", conn->error_number);
		}
		else {
			number_portion[0] = '\0';
		}

		asprintf(&errmsg, "%s%s", number_portion, conn->error_message ? conn->error_message : "");
		*errmsg_dest = errmsg;
	}

	return conn->error_number;
}

void dbi_conn_error_handler(dbi_conn Conn, dbi_conn_error_handler_func function, void *user_argument) {
	dbi_conn_t *conn = Conn;
	conn->error_handler = function;
	if (function == NULL) {
		conn->error_handler_argument = NULL;
	}
	else {
		conn->error_handler_argument = user_argument;
	}
}

dbi_error_flag dbi_conn_error_flag(dbi_conn Conn) {
	dbi_conn_t *conn = Conn;
	return conn->error_flag;
}

int dbi_conn_set_error(dbi_conn Conn, int errnum, const char *formatstr, ...) {
	dbi_conn_t *conn = Conn;
	char *msg;
	int len;
	va_list ap;
	int trigger_callback;

	if (!conn) return 0;

	trigger_callback = dbi_conn_get_option_numeric(Conn, "UserErrorTriggersCallback");

	va_start(ap, formatstr);
	len = vasprintf(&msg, formatstr, ap);
	va_end(ap);

	if (conn->error_message) free(conn->error_message);
	conn->error_message = msg;
	conn->error_number = errnum;
	conn->error_flag = DBI_ERROR_USER;

	if (trigger_callback && (conn->error_handler != NULL)) {
		/* trigger the external callback function */
		conn->error_handler((dbi_conn)conn, conn->error_handler_argument);
	}
	
	return len;
}

size_t dbi_conn_quote_string_copy(dbi_conn Conn, const char *orig, char **newquoted) {
	dbi_conn_t *conn = Conn;
	char *newstr;
	size_t newlen;
	
	if (!Conn || !orig || !newquoted) return 0;

	newstr = malloc((strlen(orig)*2)+4+1); /* worst case, we have to escape every character and add 2*2 surrounding quotes */

	if (!newstr) {
		return 0;
	}
	
	newlen = conn->driver->functions->conn_quote_string(conn, orig, newstr);
	if (!newlen) {
		free(newstr);
		return 0;
	}

	*newquoted = newstr;

	return newlen;
}

size_t dbi_conn_quote_string(dbi_conn Conn, char **orig) {
	char *temp = NULL;
	char *newstr = NULL;
	size_t newlen;

	if (!orig || !*orig) {
		return 0;
	}
	
	newlen = dbi_conn_quote_string_copy(Conn, *orig, &newstr);
	if (!newlen) {
	  /* leave original string alone in case of an error */
	  return 0;
	}
	temp = *orig;
	*orig = newstr;
	free(temp); /* original unescaped string */

	return newlen;
}

size_t dbi_conn_quote_binary_copy(dbi_conn Conn, const unsigned char *orig, size_t from_length, unsigned char **ptr_dest) {
  unsigned char *temp = NULL;
  size_t newlen;
  dbi_conn_t *conn = Conn;

  if (!Conn || !orig || !ptr_dest) {
    return 0;
  }

  newlen = conn->driver->functions->quote_binary(conn, orig, from_length, &temp);
  if (!newlen) {
    return 0;
  }

  *ptr_dest = temp;

  return newlen;
}

/* DRIVER: option manipulation */

int dbi_conn_set_option(dbi_conn Conn, const char *key, const char *value) {
	dbi_conn_t *conn = Conn;
	dbi_option_t *option;
	
	if (!conn) {
		return -1;
	}
	
	option = _find_or_create_option_node(conn, key);
	if (!option) {
		_error_handler(conn, DBI_ERROR_NOMEM);
		return -1;
	}

	if (option->string_value) free(option->string_value);
	option->string_value = (value) ? strdup(value) : NULL;
	option->numeric_value = 0;
	
	return 0;
}

int dbi_conn_set_option_numeric(dbi_conn Conn, const char *key, int value) {
	dbi_conn_t *conn = Conn;
	dbi_option_t *option;
	
	if (!conn) {
		return -1;
	}
	
	option = _find_or_create_option_node(conn, key);
	if (!option) {
		_error_handler(conn, DBI_ERROR_NOMEM);
		return -1;
	}
	
	if (option->string_value) free(option->string_value);
	option->string_value = NULL;
	option->numeric_value = value;
	
	return 0;
}

static const char *_get_option(dbi_conn Conn, const char *key, int aggressive) {
	dbi_conn_t *conn = Conn;
	dbi_option_t *option;

	if (!conn) {
		return NULL;
	}
	
	option = conn->options;
	while (option && strcasecmp(key, option->key)) {
		option = option->next;
	}

	if (option) {
		return option->string_value;
	}
	else {
		if (aggressive) _error_handler(conn, DBI_ERROR_BADNAME);
		return NULL;
	}
}

const char *dbi_conn_get_option(dbi_conn Conn, const char *key) {
	return _get_option(Conn, key, 0);
}

const char *dbi_conn_require_option(dbi_conn Conn, const char *key) {
	return _get_option(Conn, key, 1);
}

static int _get_option_numeric(dbi_conn Conn, const char *key, int aggressive) {
	dbi_conn_t *conn = Conn;
	dbi_option_t *option;

	if (!conn) return 0;
	
	option = conn->options;
	while (option && strcasecmp(key, option->key)) {
		option = option->next;
	}

	if (option) {
		return option->numeric_value;
	}
	else {
		if (aggressive) _error_handler(conn, DBI_ERROR_BADNAME);
		return 0;
	}
}

int dbi_conn_get_option_numeric(dbi_conn Conn, const char *key) {
	return _get_option_numeric(Conn, key, 0);
}

int dbi_conn_require_option_numeric(dbi_conn Conn, const char *key) {
	return _get_option_numeric(Conn, key, 1);
}

const char *dbi_conn_get_option_list(dbi_conn Conn, const char *current) {
	dbi_conn_t *conn = Conn;
	dbi_option_t *option;
	
	if (conn && conn->options) option = conn->options;
	else return NULL;
	
	if (!current) {
		return option->key;
	}
	else {
		while (option && strcasecmp(current, option->key)) {
			option = option->next;
		}
		return (option && option->next) ? option->next->key : NULL;
	}
}

void dbi_conn_clear_option(dbi_conn Conn, const char *key) {
	dbi_conn_t *conn = Conn;
	dbi_option_t *prevoption = NULL; /* shut up compiler */
	dbi_option_t *option;
	
	if (!conn) return;
	option = conn->options;
	
	while (option && strcasecmp(key, option->key)) {
		prevoption = option;
		option = option->next;
	}
	if (!option) return;
	if (option == conn->options) {
		conn->options = option->next;
	}
	else {
		prevoption->next = option->next;
	}
	free(option->key);
	free(option->string_value);
	free(option);
	return;
}

void dbi_conn_clear_options(dbi_conn Conn) {
	dbi_conn_t *conn = Conn;
	dbi_option_t *cur;
	dbi_option_t *next;

	if (!conn) return;
	cur = conn->options;
	
	while (cur) {
		next = cur->next;
		free(cur->key);
		free(cur->string_value);
		free(cur);
		cur = next;
	}

	conn->options = NULL;
}

/* DRIVER: SQL layer functions */

int dbi_conn_connect(dbi_conn Conn) {
	dbi_conn_t *conn = Conn;
	int retval;
	
	if (!conn) return -1;
	
	retval = conn->driver->functions->connect(conn);
	if (retval == -2) {
		/* a DBD-level error has already been set and the callback has already triggered */
	}
	else if (retval == -1) {
		/* couldn't create a connection and no DBD-level error information is available */
		_error_handler(conn, DBI_ERROR_NOCONN);
	}

	return retval;
}

int dbi_conn_get_socket(dbi_conn Conn){
	dbi_conn_t *conn = Conn;
	int retval;

	if (!conn) return -1;

	retval = conn->driver->functions->get_socket(conn);

	return retval;
}

const char *dbi_conn_get_encoding(dbi_conn Conn){
	dbi_conn_t *conn = Conn;
	const char *retval;

	if (!conn) return NULL;

	retval = conn->driver->functions->get_encoding(conn);

	return retval;
}

unsigned int dbi_conn_get_engine_version(dbi_conn Conn){
	dbi_conn_t *conn = Conn;
	char versionstring[VERSIONSTRING_LENGTH];

	if (!conn) return 0;

	conn->driver->functions->get_engine_version(conn, versionstring);

	return _parse_versioninfo(versionstring);
}

char* dbi_conn_get_engine_version_string(dbi_conn Conn, char *versionstring) {
	dbi_conn_t *conn = Conn;

	if (!conn) return 0;

	return conn->driver->functions->get_engine_version(conn, versionstring);
}

dbi_result dbi_conn_get_db_list(dbi_conn Conn, const char *pattern) {
	dbi_conn_t *conn = Conn;
	dbi_result_t *result;
	
	if (!conn) return NULL;
	
	result = conn->driver->functions->list_dbs(conn, pattern);
	
	if (result == NULL) {
		_error_handler(conn, DBI_ERROR_DBD);
	}

	return (dbi_result)result;
}

dbi_result dbi_conn_get_table_list(dbi_conn Conn, const char *db, const char *pattern) {
	dbi_conn_t *conn = Conn;
	dbi_result_t *result;
	
	if (!conn) return NULL;
	
	result = conn->driver->functions->list_tables(conn, db, pattern);
	
	if (result == NULL) {
		_error_handler(conn, DBI_ERROR_DBD);
	}
	
	return (dbi_result)result;
}

dbi_result dbi_conn_query(dbi_conn Conn, const char *statement) {
	dbi_conn_t *conn = Conn;
	dbi_result_t *result;

	if (!conn) return NULL;
	
	_logquery(conn, "[query] %s\n", statement);
	result = conn->driver->functions->query(conn, statement);

	if (result == NULL) {
		_error_handler(conn, DBI_ERROR_DBD);
	}

	return (dbi_result)result;
}

dbi_result dbi_conn_queryf(dbi_conn Conn, const char *formatstr, ...) {
	dbi_conn_t *conn = Conn;
	char *statement;
	dbi_result_t *result;
	va_list ap;

	if (!conn) return NULL;
	
	va_start(ap, formatstr);
	vasprintf(&statement, formatstr, ap);
	va_end(ap);
	
	_logquery(conn, "[queryf] %s\n", statement);
	result = conn->driver->functions->query(conn, statement);

	if (result == NULL) {
		_error_handler(conn, DBI_ERROR_DBD);
	}
	free(statement);
	
	return (dbi_result)result;
}

dbi_result dbi_conn_query_null(dbi_conn Conn, const unsigned char *statement, size_t st_length) {
	dbi_conn_t *conn = Conn;
	dbi_result_t *result;

	if (!conn) return NULL;

	_logquery_null(conn, statement, st_length);
	result = conn->driver->functions->query_null(conn, statement, st_length);

	if (result == NULL) {
		_error_handler(conn, DBI_ERROR_DBD);
	}
	
	return (dbi_result)result;
}

int dbi_conn_select_db(dbi_conn Conn, const char *db) {
	dbi_conn_t *conn = Conn;
	const char *retval;
	
	if (!conn) return -1;
	
	if (conn->current_db) free(conn->current_db);
	conn->current_db = NULL;
	
	retval = conn->driver->functions->select_db(conn, db);
	
	if (retval == NULL) {
		_error_handler(conn, DBI_ERROR_DBD);
		return -1;
	}
	
	if (retval[0] == '\0') {
		/* if "" was returned, conn doesn't support switching databases */
		_error_handler(conn, DBI_ERROR_UNSUPPORTED);
		return -1;
	}
	else {
		conn->current_db = strdup(retval);
	}
	
	return 0;
}

unsigned long long dbi_conn_sequence_last(dbi_conn Conn, const char *name) {
	dbi_conn_t *conn = Conn;
	unsigned long long result;
	if (!conn) return 0;
	result = conn->driver->functions->get_seq_last(conn, name);
	return result;
}

unsigned long long dbi_conn_sequence_next(dbi_conn Conn, const char *name) {
	dbi_conn_t *conn = Conn;
	unsigned long long result;
	if (!conn) return 0;
	result = conn->driver->functions->get_seq_next(conn, name);
	return result;
}

int dbi_conn_ping(dbi_conn Conn) {
	dbi_conn_t *conn = Conn;
	int result;

	if (!conn) return 0;
	result = conn->driver->functions->ping(conn);
	return result;
}

/* XXX INTERNAL PRIVATE IMPLEMENTATION FUNCTIONS XXX */

static dbi_driver_t *_get_driver(const char *filename) {
	dbi_driver_t *driver;
	void *dlhandle;
	const char **custom_functions_list;
	unsigned int idx = 0;
	dbi_custom_function_t *prevcustom = NULL;
	dbi_custom_function_t *custom = NULL;
	char function_name[256];

	dlhandle = my_dlopen(filename, DLOPEN_FLAG); /* DLOPEN_FLAG defined by autoconf */

	if (dlhandle == NULL) {
	  fprintf(stderr, "%s\n", my_dlerror());
		return NULL;
	}
	else {
		driver = malloc(sizeof(dbi_driver_t));
		if (!driver) return NULL;

		driver->dlhandle = dlhandle;
		driver->filename = strdup(filename);
		driver->next = NULL;
		driver->caps = NULL;
		driver->functions = malloc(sizeof(dbi_functions_t));

		if ( /* nasty looking if block... is there a better way to do it? */
			((driver->functions->register_driver = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_register_driver")) == NULL) ||
			((driver->functions->initialize = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_initialize")) == NULL) ||
			((driver->functions->connect = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_connect")) == NULL) ||
			((driver->functions->disconnect = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_disconnect")) == NULL) ||
			((driver->functions->fetch_row = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_fetch_row")) == NULL) ||
			((driver->functions->free_query = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_free_query")) == NULL) ||
			((driver->functions->goto_row = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_goto_row")) == NULL) ||
			((driver->functions->get_socket = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_get_socket")) == NULL) ||
			((driver->functions->get_encoding = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_get_encoding")) == NULL) ||
			((driver->functions->encoding_from_iana = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_encoding_from_iana")) == NULL) ||
			((driver->functions->encoding_to_iana = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_encoding_to_iana")) == NULL) ||
			((driver->functions->get_engine_version = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_get_engine_version")) == NULL) ||
			((driver->functions->list_dbs = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_list_dbs")) == NULL) ||
			((driver->functions->list_tables = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_list_tables")) == NULL) ||
			((driver->functions->query = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_query")) == NULL) ||
			((driver->functions->query_null = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_query_null")) == NULL) ||
			((driver->functions->quote_string = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_quote_string")) == NULL) ||
			((driver->functions->quote_binary = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_quote_binary")) == NULL) ||
			((driver->functions->conn_quote_string = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_conn_quote_string")) == NULL) ||
			((driver->functions->select_db = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_select_db")) == NULL) ||
			((driver->functions->geterror = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_geterror")) == NULL) ||
			((driver->functions->get_seq_last = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_get_seq_last")) == NULL) ||
			((driver->functions->get_seq_next = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_get_seq_next")) == NULL) ||
			((driver->functions->ping = my_dlsym(dlhandle, DLSYM_PREFIX "dbd_ping")) == NULL)
			)
		{
			free(driver->functions);
			free(driver->filename);
			free(driver);
			return NULL;
		}
		driver->functions->register_driver(&driver->info, &custom_functions_list, &driver->reserved_words);
		driver->custom_functions = NULL; /* in case no custom functions are available */
		while (custom_functions_list && custom_functions_list[idx] != NULL) {
			custom = malloc(sizeof(dbi_custom_function_t));
			if (!custom) {
				_free_custom_functions(driver);
				free(driver->functions);
				free(driver->filename);
				free(driver);
				return NULL;
			}
			custom->next = NULL;
			custom->name = custom_functions_list[idx];
			snprintf(function_name, 256, DLSYM_PREFIX "dbd_%s", custom->name);
			custom->function_pointer = my_dlsym(dlhandle, function_name);
			if (!custom->function_pointer) {
				_free_custom_functions(driver);
				free(custom); /* not linked into the list yet */
				free(driver->functions);
				free(driver->filename);
				free(driver);
				return NULL;
			}
			if (driver->custom_functions == NULL) {
				driver->custom_functions = custom;
			}
			else {
				prevcustom->next = custom;
			}
			prevcustom = custom;
			idx++;
		}
	}
	return driver;
}

static void _free_custom_functions(dbi_driver_t *driver) {
	dbi_custom_function_t *cur;
	dbi_custom_function_t *next;

	if (!driver) return;
	cur = driver->custom_functions;

	while (cur) {
		next = cur->next;
		free(cur);
		cur = next;
	}

	driver->custom_functions = NULL;
}

static void _free_caps(_capability_t *caproot) {
	_capability_t *cap = caproot;
	while (cap) {
		_capability_t *nextcap = cap->next;
		if (cap->name) free(cap->name);
		free(cap);
		cap = nextcap;
	}
	return;
}

static int _update_internal_conn_list(dbi_conn_t *conn, const int operation) {
	/* maintain internal linked list of conns so that we can unload them all
	 * when dbi is shutdown
	 * 
	 * operation = -1: remove conn
	 *           =  0: just look for conn (return 1 if found, -1 if not)
	 *           =  1: add conn */
	dbi_conn_t *curconn = rootconn;
	dbi_conn_t *prevconn = NULL;

	if ((operation == -1) || (operation == 0)) {
		while (curconn && (curconn != conn)) {
			prevconn = curconn;
			curconn = curconn->next;
		}
		if (!curconn) return -1;
		if (operation == 0) return 1;
		else if (operation == -1) {
			if (prevconn) prevconn->next = curconn->next;
			else rootconn = NULL;
			return 0;
		}
	}
	else if (operation == 1) {
		while (curconn && curconn->next) {
			curconn = curconn->next;
		}
		if (curconn) {
			curconn->next = conn;
		}
		else {
			rootconn = conn;
		}
		conn->next = NULL;
		return 0;
	}
	return -1;
}

static dbi_option_t *_find_or_create_option_node(dbi_conn Conn, const char *key) {
	dbi_option_t *prevoption = NULL;
	dbi_conn_t *conn = Conn;
	dbi_option_t *option = conn->options;

	while (option && strcasecmp(key, option->key)) {
		prevoption = option;
		option = option->next;
	}

	if (option == NULL) {
		/* allocate a new option node */
		option = malloc(sizeof(dbi_option_t));
		if (!option) return NULL;
		option->next = NULL;
		option->key = strdup(key);
		option->string_value = NULL;
		if (conn->options == NULL) {
		    conn->options = option;
		}
		else {
		    prevoption->next = option;
		}
	}

	return option;
}

#define COUNTOF(array) (sizeof(array)/sizeof((array)[0]))

void _error_handler(dbi_conn_t *conn, dbi_error_flag errflag) {
	int my_errno = 0;
	char *errmsg = NULL;
	int errstatus;
	static const char *errflag_messages[] = {
		/* DBI_ERROR_USER */		NULL,
		/* DBI_ERROR_NONE */		NULL,
		/* DBI_ERROR_DBD */			NULL,
		/* DBI_ERROR_BADOBJECT */	"An invalid or NULL object was passed to libdbi",
		/* DBI_ERROR_BADTYPE */		"The requested variable type does not match what libdbi thinks it should be",
		/* DBI_ERROR_BADIDX */		"An invalid or out-of-range index was passed to libdbi",
		/* DBI_ERROR_BADNAME */		"An invalid name was passed to libdbi",
		/* DBI_ERROR_UNSUPPORTED */	"This particular libdbi driver or connection does not support this feature",
		/* DBI_ERROR_NOCONN */		"libdbi could not establish a connection",
		/* DBI_ERROR_NOMEM */		"libdbi ran out of memory",
		/* DBI_ERROR_BADPTR */		"An invalid pointer was passed to libdbi"};
	
	if (conn == NULL) {
		/* temp hack... if a result is disjoined and encounters an error, conn
		 * will be null when we get here. just ignore it, since we assume
		 * errors require a valid conn. this shouldn't even be a problem now,
		 * since (currently) the only reason a result would be disjoint is if a
		 * garbage collector was about to get rid of it. */
		// conn will also be NULL if the connection itself could not be created,
		// or if a NULL result handle was passed to a dbi routine, so we would
		// always want to return if NULL. Probably should say something though:
		fprintf(stderr, "libdbi: _error_handler: %s (NULL conn/result handle)\n",
				errflag >= DBI_ERROR_BADOBJECT-1 && errflag < COUNTOF(errflag_messages)-1
					? errflag_messages[errflag+1] : "");
		return;
	}

	if (errflag == DBI_ERROR_DBD) {
		errstatus = conn->driver->functions->geterror(conn, &my_errno, &errmsg);

		if (errstatus == -1) {
			/* not _really_ an error. XXX debug this, does it ever actually happen? */
			return;
		}
	}

	if (conn->error_message) free(conn->error_message);

	if (errflag >= -1 && errflag < COUNTOF(errflag_messages)-1 
			&& errflag_messages[errflag+1] != NULL) {
		errmsg = strdup(errflag_messages[errflag+1]);
	}
	
	conn->error_flag = errflag;
	conn->error_number = my_errno;
	conn->error_message = errmsg;
	
	if (conn->error_handler != NULL) {
		/* trigger the external callback function */
		conn->error_handler((dbi_conn)conn, conn->error_handler_argument);
	}
}

void _verbose_handler(dbi_conn_t *conn, const char* fmt, ...) {
	va_list ap;

	//if(conn && dbi_conn_get_option_numeric(conn, "Verbosity"))
	{
	  fputs("libdbi: ",stderr);
	  va_start(ap, fmt);
	  vfprintf(stderr, fmt, ap);
	  va_end(ap);
	}
}

void _logquery(dbi_conn_t *conn, const char* fmt, ...) {
	va_list ap;

	if(conn && dbi_conn_get_option_numeric(conn, "LogQueries")){
	  fputs("libdbi: ", stderr);
	  va_start(ap, fmt);
	  vfprintf(stderr, fmt, ap);
	  va_end(ap);
	}
}

void _logquery_null(dbi_conn_t *conn, const char* statement, size_t st_length) {
	if(conn && dbi_conn_get_option_numeric(conn, "LogQueries")){
	  fputs("libdbi: [query_null] ", stderr);
	  fwrite(statement, 1, st_length, stderr);
	  fputc('\n', stderr);
	}
}

unsigned int _isolate_attrib(unsigned int attribs, unsigned int rangemin, unsigned int rangemax) {
	/* hahaha! who woulda ever thunk strawberry's code would come in handy? */
	// find first (highest) bit set; methods not using FP can be found at 
	// http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogObvious
	unsigned startbit = log(rangemin)/log(2);
	unsigned endbit = log(rangemax)/log(2);
	// construct mask from startbit to endbit inclusive
	unsigned attrib_mask = ((1<<(endbit+1))-1) ^ ((1<<startbit)-1);
	return attribs & attrib_mask;
}

/* computes an int from a [[[[A.]B.]C.]D.]E version number according to this
  formula: version = E + D*100 + C*10000 + B*1000000 + A*100000000 */
static unsigned int _parse_versioninfo(const char *version) {
  char my_version[VERSIONSTRING_LENGTH];
  char* start;
  char* dot;
  int i = 0;
  unsigned int n_version = 0;
  unsigned int n_multiplier = 1;

  if (!version || !*version) {
    return 0;
  }

  /* get a copy of version to mangle */
  strncpy(my_version, version, VERSIONSTRING_LENGTH-1);
  my_version[VERSIONSTRING_LENGTH-1] = '\0';

  /* remove trailing periods */
  if (my_version[strlen(my_version)-1] == '.') {
    my_version[strlen(my_version)-1] = '\0';
  }

  start = my_version;
  while ((dot = strrchr(start, (int)'.')) != NULL && i<5) {
    n_version += atoi(dot+1) * n_multiplier;
    *dot = '\0';
    n_multiplier *= 100;
    i++;
  }
  
  /* take care of the remainder */
  n_version += atoi(start) * n_multiplier;

  if (i==5) {
    /* version string can't be encoded in an unsigned int */
    return 0;
  }
  return n_version;
}

#if HAVE_MACH_O_DYLD_H
static int dyld_error_set=0;
static void * dyld_dlopen(const char * file)
{
	NSObjectFileImage o=NULL;
	NSObjectFileImageReturnCode r;
	NSModule m=NULL;
	const unsigned int flags =  NSLINKMODULE_OPTION_RETURN_ON_ERROR | NSLINKMODULE_OPTION_PRIVATE;
	dyld_error_set=0;
	r = NSCreateObjectFileImageFromFile(file,&o);
	if (NSObjectFileImageSuccess == r)
	{
		m=NSLinkModule(o,file,flags);
		NSDestroyObjectFileImage(o);
		if (!m) dyld_error_set=1;
	}
        return (void*)m;
}
static void * dyld_dlsym(void * hand, const char * name)
{
        NSSymbol sym=NSLookupSymbolInModule((NSModule)hand, name);
	void * addr = NULL;
	dyld_error_set=0;
	if (sym) addr=(void*)NSAddressOfSymbol(sym);
	if (!addr) dyld_error_set=1;
        return addr;
}
static int dyld_dlclose(void * hand)
{
        int retVal=0;
	dyld_error_set=0;
        if (!NSUnLinkModule((NSModule)hand, 0))
	{
	        dyld_error_set=1;
		retVal=-1;
	}
        return retVal;
}

static const char * dyld_dlerror()
{
	NSLinkEditErrors ler;
	int lerno;
	const char *errstr;
	const char *file;
	NSLinkEditError(&ler, &lerno, &file, &errstr);
	if (!dyld_error_set) errstr=NULL;
	dyld_error_set=0;
	return errstr;
}
#endif /* HAVE_MACH_O_DYLD_H */

#ifdef __MINGW32__
static char win_errstr[512];
static int win_err_set = 0;
void *win_dlopen(const char *filename, int mode)
{
  HINSTANCE handle;
  handle = LoadLibrary(filename);
#ifdef _WIN32
  if (! handle) {
    sprintf(win_errstr, "Error code 1(%d) while loading library %s", GetLastError(), filename);
	win_err_set =1;
    return NULL;
  }
#else
  if ((UINT) handle < 32) {
    sprintf(win_errstr, "error code 1(%d) while loading library %s", (UINT) handle, filename);
	win_err_set =1;
    return NULL;
  }
#endif
  return (void *) handle;
}

void *win_dlsym(void *handle1, const char *symname)
{
  HMODULE handle = (HMODULE) handle1;
  void *symaddr;
  symaddr = (void *) GetProcAddress(handle, symname);
  if (symaddr == NULL)
  {
    sprintf(win_errstr, "can not find symbol %s", symname);
	win_err_set =2;
  }
  return symaddr;
}

int win_dlclose(void *handle1)
{
  HMODULE handle = (HMODULE) handle1;
#ifdef _WIN32
  if (FreeLibrary(handle))
    return 0;
  else {
    sprintf(win_errstr, "error code 3(%d) while closing library", GetLastError());
	win_err_set =3;
    return -1;
  }
#else
  FreeLibrary(handle);
  return 0;
#endif
}

char *win_dlerror()
{
  return win_errstr;
}

#endif