php-src/ext/interbase/ibase_events.c

/*
   +----------------------------------------------------------------------+
   | PHP Version 5                                                        |
   +----------------------------------------------------------------------+
   | Copyright (c) 1997-2004 The PHP Group                                |
   +----------------------------------------------------------------------+
   | This source file is subject to version 3.0 of the PHP license,       |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.php.net/license/3_0.txt.                                  |
   | If you did not receive a copy of the PHP license and are unable to   |
   | obtain it through the world-wide-web, please send a note to          |
   | license@php.net so we can mail you a copy immediately.               |
   +----------------------------------------------------------------------+
   | Authors: Ard Biesheuvel <a.k.biesheuvel@its.tudelft.nl>              |
   +----------------------------------------------------------------------+
 */

/* $Id$ */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "php.h"

#if HAVE_IBASE

#include "php_interbase.h"
#include "interbase.h"

void _php_ibase_event_free(char *event_buf, char *result_buf) /* {{{ */
{
	isc_free(event_buf);
	isc_free(result_buf);
}
/* }}} */

static void _php_ibase_event_block(ibase_db_link *ib_link, unsigned short count, char **events, 
	unsigned short *l, char **event_buf, char **result_buf) /* {{{ */
{
	ISC_STATUS dummy_result[20];
	unsigned long dummy_count[15];

	/**
	 * Unfortunately, there's no clean and portable way in C to pass arguments to 
	 * a variadic function if you don't know the number of arguments at compile time.
	 * (And even if there were a way, the Interbase API doesn't provide a version of
	 * this function that takes a va_list as an argument)
	 *
	 * In this case, the number of arguments is limited to 18 by the underlying API,
	 * so we can work around it.
	 */

	*l = (unsigned short) isc_event_block(event_buf, result_buf, count, events[0], 
		events[1], events[2], events[3], events[4], events[5], events[6], events[7], 
		events[8], events[9], events[10], events[11], events[12], events[13], events[14]);

	/**
	 * Currently, this is the only way to correctly initialize an event buffer.
	 * This is clearly something that should be fixed, cause the semantics of
	 * isc_wait_for_event() indicate that it blocks until an event occurs.
	 * If the Firebird people ever fix this, these lines should be removed,
	 * otherwise, events will have to fire twice before ibase_wait_event() returns.
	 */

	isc_wait_for_event(dummy_result, &ib_link->handle, *l, *event_buf, *result_buf);
	isc_event_counts(dummy_count, *l, *event_buf, *result_buf);
}
/* }}} */

/* {{{ proto string ibase_wait_event([resource link_identifier,] string event [, string event [, ...]])
   Waits for any one of the passed Interbase events to be posted by the database, and returns its name */
PHP_FUNCTION(ibase_wait_event)
{
	zval ***args;
	ibase_db_link *ib_link;
	char *event_buffer, *result_buffer, *events[15];
	unsigned short i = 0, event_count = 0, buffer_size;
	unsigned long occurred_event[15];
	
	RESET_ERRMSG;

	/* no more than 15 events */
	if (ZEND_NUM_ARGS() < 1 || ZEND_NUM_ARGS() > 16) {
		WRONG_PARAM_COUNT;
	}

	args = (zval ***) safe_emalloc(sizeof(zval **), ZEND_NUM_ARGS(), 0);
	if (zend_get_parameters_array_ex(ZEND_NUM_ARGS(), args) == FAILURE) {
		efree(args);
		RETURN_FALSE;
	}

	if (Z_TYPE_PP(args[0]) == IS_RESOURCE) {

		ZEND_FETCH_RESOURCE2(ib_link, ibase_db_link *, args[0], -1, "InterBase link", le_link, le_plink);
		i = 1;

	} else {

		if (ZEND_NUM_ARGS() > 15) {
			efree(args);
			WRONG_PARAM_COUNT;
		}

		ZEND_FETCH_RESOURCE2(ib_link, ibase_db_link *, NULL, IBG(default_link), "InterBase link", le_link, le_plink);
	}				
		
	for (; i < ZEND_NUM_ARGS(); ++i) {
		convert_to_string_ex(args[i]);
		events[event_count++] = Z_STRVAL_PP(args[i]);
	}

	/* fills the required data structure with information about the events */
	_php_ibase_event_block(ib_link, event_count, events, &buffer_size, &event_buffer, &result_buffer);

	/* now block until an event occurs */
	if (isc_wait_for_event(IB_STATUS, &ib_link->handle, buffer_size, event_buffer, result_buffer)) {
		_php_ibase_error(TSRMLS_C);
		_php_ibase_event_free(event_buffer,result_buffer);
		efree(args);
		RETURN_FALSE;
	}
	
	/* find out which event occurred */
	isc_event_counts(occurred_event, buffer_size, event_buffer, result_buffer);
	for (i = 0; i < event_count; ++i) {
		if (occurred_event[i]) {
			char *result = estrdup(events[i]);
			_php_ibase_event_free(event_buffer,result_buffer);
			efree(args);
			RETURN_STRING(result,0);
		}
	}
	
	/* If we reach this line, isc_wait_for_event() did return, but we don't know
	   which event fired. */
	_php_ibase_event_free(event_buffer,result_buffer);
	efree(args);
	RETURN_FALSE;
}
/* }}} */

static isc_callback _php_ibase_callback(ibase_event *event, 
	unsigned short buffer_size, char *result_buf) /* {{{ */
{
	/* this function is called asynchronously by the Interbase client library. */
	TSRMLS_FETCH_FROM_CTX(event->thread_ctx);
	
	/**
	 * The callback function is called when the event is first registered and when the event
	 * is cancelled. I consider this is a bug. By clearing event->callback, we make sure 
	 * nothing happens if no event was actually posted.
	 */
	if (event->callback != NULL) {

		unsigned short i;
		unsigned long occurred_event[15];
		zval event_name, link_id, return_value, *args[2];

		/* initialize at runtime to satisify picky compilers */
		args[0] = &event_name; 
		args[1] = &link_id; 
		
		/* copy the updated results into the result buffer */
		memcpy(event->result_buffer, result_buf, buffer_size);
		
		INIT_ZVAL(event_name);
		INIT_ZVAL(link_id);
		ZVAL_RESOURCE(&link_id, event->link_res_id);

		/* find out which event occurred */
		isc_event_counts(occurred_event, buffer_size, event->event_buffer, event->result_buffer);
		for (i = 0; i < event->event_count; ++i) {
			if (occurred_event[i]) {
				ZVAL_STRING(&event_name,event->events[i],0);
				break;
			}
		}	

		/* call the callback provided by the user */
		if (SUCCESS != call_user_function(EG(function_table), NULL, 
				event->callback, &return_value, 2, args TSRMLS_CC)) {
			_php_ibase_module_error("Error calling callback %s" TSRMLS_CC, Z_STRVAL_P(event->callback));
			return 0;
		}

		if (Z_TYPE(return_value) == IS_BOOL && !Z_BVAL(return_value)) {
			return 0;
		}			
	}
		
	/* re-register the event */
	if (isc_que_events(IB_STATUS, &event->link->handle, &event->event_id, buffer_size, 
		event->event_buffer,(isc_callback)_php_ibase_callback, (void *)event)) {

		_php_ibase_error(TSRMLS_C);
	}
	return 0;
}
/* }}} */

/* {{{ proto resource ibase_set_event_handler([resource link_identifier,] callback handler, string event [, string event [, ...]])
   Register the callback for handling each of the named events */
PHP_FUNCTION(ibase_set_event_handler)
{
	/**
	 * The callback passed to this function should take an event name (string) and a 
	 * link resource id (int) as arguments. The value returned from the function is 
	 * used to determine if the event handler should remain set.
	 */

	zval ***args, **cb_arg;
	ibase_db_link *ib_link;
	ibase_event *event;
	char *callback_name;
	unsigned short i = 1, buffer_size;
	int link_res_id;
		
	RESET_ERRMSG;

	/* no more than 15 events */
	if (ZEND_NUM_ARGS() < 1 || ZEND_NUM_ARGS() > 17) {
		WRONG_PARAM_COUNT;
	}

	args = (zval ***) safe_emalloc(sizeof(zval **), ZEND_NUM_ARGS(), 0);
	if (zend_get_parameters_array_ex(ZEND_NUM_ARGS(), args) == FAILURE) {
		efree(args);
		RETURN_FALSE;
	}

	/* get a working link */
	if (Z_TYPE_PP(args[0]) != IS_STRING) {

		cb_arg = args[1];
		i = 2;

		ZEND_FETCH_RESOURCE2(ib_link, ibase_db_link *, args[0], -1, 
			"InterBase link", le_link, le_plink);

		convert_to_long_ex(args[0]);
		link_res_id = Z_LVAL_PP(args[0]);

	} else {

		if (ZEND_NUM_ARGS() > 16) {
			efree(args);
			WRONG_PARAM_COUNT;
		}

		cb_arg = args[0];

		ZEND_FETCH_RESOURCE2(ib_link, ibase_db_link *, NULL, IBG(default_link), 
			"InterBase link", le_link, le_plink);
		link_res_id = IBG(default_link);
	}				
		
	/* get the callback */
	if (!zend_is_callable(*cb_arg, 0, &callback_name)) {
		_php_ibase_module_error("Callback argument %s is not a callable function"
			TSRMLS_CC, callback_name);
		efree(callback_name);
		efree(args);
		RETURN_FALSE;
	}
	efree(callback_name);
		
	/* allocate the event resource */
	event = (ibase_event *) safe_emalloc(sizeof(ibase_event), 1, 0);
	TSRMLS_SET_CTX(event->thread_ctx);
	event->link_res_id = link_res_id;
	event->link = ib_link;
	event->event_count = 0;
	event->callback = NULL;
	event->events = (char **) safe_emalloc(sizeof(char *),ZEND_NUM_ARGS()-i,0);
		
	for (; i < ZEND_NUM_ARGS(); ++i) {
		convert_to_string_ex(args[i]);
		event->events[event->event_count++] = estrdup(Z_STRVAL_PP(args[i]));
	}

	/* fills the required data structure with information about the events */
	_php_ibase_event_block(ib_link, event->event_count, event->events, 
		&buffer_size, &event->event_buffer, &event->result_buffer);
		
	/* now register the events with the Interbase API */
	if (isc_que_events(IB_STATUS, &ib_link->handle, &event->event_id, buffer_size, 
		event->event_buffer,(isc_callback)_php_ibase_callback, (void *)event)) {
			
		_php_ibase_error(TSRMLS_C);
		efree(args);
		efree(event);
		RETURN_FALSE;
	}

	ALLOC_ZVAL(event->callback);
	*event->callback = **cb_arg;
	INIT_PZVAL(event->callback);
	zval_copy_ctor(event->callback);
	
	efree(args);

	ZEND_REGISTER_RESOURCE(return_value, event, le_event);
	zend_list_addref(Z_LVAL_P(return_value));
}

/* {{{ proto bool ibase_free_event_handler(resource event)
   Frees the event handler set by ibase_set_event_handler() */
PHP_FUNCTION(ibase_free_event_handler)
{
	zval **event_arg;
	ibase_event *event;
	
	RESET_ERRMSG;
	
	if (ZEND_NUM_ARGS() != 1 || zend_get_parameters_ex(1, &event_arg) == FAILURE) {
		WRONG_PARAM_COUNT;
	}

	ZEND_FETCH_RESOURCE(event, ibase_event *, event_arg, -1, "Interbase event", le_event);
	zend_list_delete(Z_LVAL_PP(event_arg));
	RETURN_TRUE;
}	
/* }}} */

#endif /* HAVE_IBASE */

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