From c4dd7a1a684490673e25aaf4fabec5df138854c4 Mon Sep 17 00:00:00 2001 From: Lorry Tar Creator Date: Thu, 14 Mar 2013 05:42:27 +0000 Subject: Imported from /home/lorry/working-area/delta_php2/php-5.4.13.tar.bz2. --- README.PARAMETER_PARSING_API | 219 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 219 insertions(+) create mode 100644 README.PARAMETER_PARSING_API (limited to 'README.PARAMETER_PARSING_API') diff --git a/README.PARAMETER_PARSING_API b/README.PARAMETER_PARSING_API new file mode 100644 index 0000000..927e481 --- /dev/null +++ b/README.PARAMETER_PARSING_API @@ -0,0 +1,219 @@ +New parameter parsing functions +=============================== + +It should be easier to parse input parameters to an extension function. +Hence, borrowing from Python's example, there are now a set of functions +that given the string of type specifiers, can parse the input parameters +and store the results in the user specified variables. This avoids most +of the IS_* checks and convert_to_* conversions. The functions also +check for the appropriate number of parameters, and try to output +meaningful error messages. + + +Prototypes +---------- +/* Implemented. */ +int zend_parse_parameters(int num_args TSRMLS_DC, char *type_spec, ...); +int zend_parse_parameters_ex(int flags, int num_args TSRMLS_DC, char *type_spec, ...); + +The zend_parse_parameters() function takes the number of parameters +passed to the extension function, the type specifier string, and the +list of pointers to variables to store the results in. The _ex() version +also takes 'flags' argument -- current only ZEND_PARSE_PARAMS_QUIET can +be used as 'flags' to specify that the function should operate quietly +and not output any error messages. + +Both functions return SUCCESS or FAILURE depending on the result. + +The auto-conversions are performed as necessary. Arrays, objects, and +resources cannot be auto-converted. + + +Type specifiers +--------------- + The following list shows the type specifier, its meaning and the parameter + types that need to be passed by address. All passed paramaters are set + if the PHP parameter is non optional and untouched if optional and the + parameter is not present. The only exception is O where the zend_class_entry* + has to be provided on input and is used to verify the PHP parameter is an + instance of that class. + + a - array (zval*) + A - array or object (zval *) + b - boolean (zend_bool) + C - class (zend_class_entry*) + d - double (double) + f - function or array containing php method call info (returned as + zend_fcall_info and zend_fcall_info_cache) + h - array (returned as HashTable*) + H - array or HASH_OF(object) (returned as HashTable*) + l - long (long) + L - long, limits out-of-range numbers to LONG_MAX/LONG_MIN (long) + o - object of any type (zval*) + O - object of specific type given by class entry (zval*, zend_class_entry) + p - valid path (string without null bytes in the middle) and its length (char*, int) + r - resource (zval*) + s - string (with possible null bytes) and its length (char*, int) + z - the actual zval (zval*) + Z - the actual zval (zval**) + * - variable arguments list (0 or more) + + - variable arguments list (1 or more) + + The following characters also have a meaning in the specifier string: + | - indicates that the remaining parameters are optional, they + should be initialized to default values by the extension since they + will not be touched by the parsing function if they are not + passed to it. + / - use SEPARATE_ZVAL_IF_NOT_REF() on the parameter it follows + ! - the parameter it follows can be of specified type or NULL (applies + to all specifiers except for 'b', 'l', and 'd'). If NULL is passed, the + results pointer is set to NULL as well. + + +Note on 64bit compatibility +--------------------------- +Please do not forget that int and long are two different things on 64bit +OSes (int is 4 bytes and long is 8 bytes), so make sure you pass longs to "l" +and ints to strings length (i.e. for "s" you need to pass char * and int), +not the other way round! +Remember: "l" is the only case when you need to pass long (and that's why +it's "l", not "i" btw). + +Both mistakes cause memory corruptions and segfaults on 64bit OSes: +1) + char *str; + long str_len; /* XXX THIS IS WRONG!! Use int instead. */ + zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len) + +2) + int num; /* XXX THIS IS WRONG!! Use long instead. */ + zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &num) + +If you're in doubt, use check_parameters.php script to the parameters +and their types (it can be found in ./scripts/dev/ directory of PHP sources): + +# php ./scripts/dev/check_parameters.php /path/to/your/sources/ + + +Examples +-------- +/* Gets a long, a string and its length, and a zval */ +long l; +char *s; +int s_len; +zval *param; +if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "lsz", + &l, &s, &s_len, ¶m) == FAILURE) { + return; +} + + +/* Gets an object of class specified by my_ce, and an optional double. */ +zval *obj; +double d = 0.5; +zend_class_entry *my_ce; +if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "O|d", + &obj, my_ce, &d) == FAILURE) { + return; +} + + +/* Gets an object or null, and an array. + If null is passed for object, obj will be set to NULL. */ +zval *obj; +zval *arr; +if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "o!a", + &obj, &arr) == FAILURE) { + return; +} + + +/* Gets a separated array which can also be null. */ +zval *arr; +if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a/!", + &arr) == FAILURE) { + return; +} + +/* Get either a set of 3 longs or a string. */ +long l1, l2, l3; +char *s; +/* + * The function expects a pointer to a integer in this case, not a long + * or any other type. If you specify a type which is larger + * than a 'int', the upper bits might not be initialized + * properly, leading to random crashes on platforms like + * Tru64 or Linux/Alpha. + */ +int length; + +if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC, + "lll", &l1, &l2, &l3) == SUCCESS) { + /* manipulate longs */ +} else if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC, + "s", &s, &length) == SUCCESS) { + /* manipulate string */ +} else { + /* output error */ + + return; +} + + +/* Function that accepts only varargs (0 or more) */ + +int i, num_varargs; +zval ***varargs = NULL; + + +if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "*", &varargs, &num_varargs) == FAILURE) { + return; +} + +for (i = 0; i < num_varargs; i++) { + /* do something with varargs[i] */ +} + +if (varargs) { + efree(varargs); +} + + +/* Function that accepts a string, followed by varargs (1 or more) */ + +char *str; +int str_len; +int i, num_varargs; +zval ***varargs = NULL; + +if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s+", &str, &str_len, &varargs, &num_varargs) == FAILURE) { + return; +} + +for (i = 0; i < num_varargs; i++) { + /* do something with varargs[i] */ +} + +if (varargs) { + efree(varargs); +} + + +/* Function that takes an array, followed by varargs, and ending with a long */ +long num; +zval *array; +int i, num_varargs; +zval ***varargs = NULL; + +if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a*l", &array, &varargs, &num_varargs, &num) == FAILURE) { + return; +} + +for (i = 0; i < num_varargs; i++) { + /* do something with varargs[i] */ +} + +if (varargs) { + efree(varargs); +} + -- cgit v1.2.1