1New parameter parsing functions 2=============================== 3 4It should be easier to parse input parameters to an extension function. 5Hence, borrowing from Python's example, there are now a set of functions 6that given the string of type specifiers, can parse the input parameters 7and store the results in the user specified variables. This avoids most 8of the IS_* checks and convert_to_* conversions. The functions also 9check for the appropriate number of parameters, and try to output 10meaningful error messages. 11 12 13Prototypes 14---------- 15/* Implemented. */ 16int zend_parse_parameters(int num_args TSRMLS_DC, char *type_spec, ...); 17int zend_parse_parameters_ex(int flags, int num_args TSRMLS_DC, char *type_spec, ...); 18 19The zend_parse_parameters() function takes the number of parameters 20passed to the extension function, the type specifier string, and the 21list of pointers to variables to store the results in. The _ex() version 22also takes 'flags' argument -- current only ZEND_PARSE_PARAMS_QUIET can 23be used as 'flags' to specify that the function should operate quietly 24and not output any error messages. 25 26Both functions return SUCCESS or FAILURE depending on the result. 27 28The auto-conversions are performed as necessary. Arrays, objects, and 29resources cannot be auto-converted. 30 31PHP 5.5 includes a new function: 32 33int zend_parse_parameter(int flags, int arg_num TSRMLS_DC, zval **arg, const char *spec, ...); 34 35This function behaves like zend_parse_parameters_ex() except that instead of 36reading the arguments from the stack, it receives a single zval to convert 37(passed with double indirection). The passed zval may be changed in place as 38part of the conversion process. 39 40See also https://wiki.php.net/rfc/zpp_improv#expose_zend_parse_arg_as_zend_parse_parameter 41 42 43Type specifiers 44--------------- 45 The following list shows the type specifier, its meaning and the parameter 46 types that need to be passed by address. All passed parameters are set 47 if the PHP parameter is non optional and untouched if optional and the 48 parameter is not present. The only exception is O where the zend_class_entry* 49 has to be provided on input and is used to verify the PHP parameter is an 50 instance of that class. 51 52 a - array (zval*) 53 A - array or object (zval *) 54 b - boolean (zend_bool) 55 C - class (zend_class_entry*) 56 d - double (double) 57 f - function or array containing php method call info (returned as 58 zend_fcall_info and zend_fcall_info_cache) 59 h - array (returned as HashTable*) 60 H - array or HASH_OF(object) (returned as HashTable*) 61 l - long (long) 62 L - long, limits out-of-range numbers to LONG_MAX/LONG_MIN (long) 63 o - object of any type (zval*) 64 O - object of specific type given by class entry (zval*, zend_class_entry) 65 p - valid path (string without null bytes in the middle) and its length (char*, int) 66 r - resource (zval*) 67 s - string (with possible null bytes) and its length (char*, int) 68 z - the actual zval (zval*) 69 Z - the actual zval (zval**) 70 * - variable arguments list (0 or more) 71 + - variable arguments list (1 or more) 72 73 The following characters also have a meaning in the specifier string: 74 | - indicates that the remaining parameters are optional, they 75 should be initialized to default values by the extension since they 76 will not be touched by the parsing function if they are not 77 passed to it. 78 / - use SEPARATE_ZVAL_IF_NOT_REF() on the parameter it follows 79 ! - the parameter it follows can be of specified type or NULL. If NULL is 80 passed and the output for such type is a pointer, then the output 81 pointer is set to a native NULL pointer. 82 For 'b', 'l' and 'd', an extra argument of type zend_bool* must be 83 passed after the corresponding bool*, long* or double* arguments, 84 respectively. A non-zero value will be written to the zend_bool iif a 85 PHP NULL is passed. 86 87 88Note on 64bit compatibility 89--------------------------- 90Please do not forget that int and long are two different things on 64bit 91OSes (int is 4 bytes and long is 8 bytes), so make sure you pass longs to "l" 92and ints to strings length (i.e. for "s" you need to pass char * and int), 93not the other way round! 94Remember: "l" is the only case when you need to pass long (and that's why 95it's "l", not "i" btw). 96 97Both mistakes cause memory corruptions and segfaults on 64bit OSes: 981) 99 char *str; 100 long str_len; /* XXX THIS IS WRONG!! Use int instead. */ 101 zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len) 102 1032) 104 int num; /* XXX THIS IS WRONG!! Use long instead. */ 105 zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &num) 106 107If you're in doubt, use check_parameters.php script to the parameters 108and their types (it can be found in ./scripts/dev/ directory of PHP sources): 109 110# php ./scripts/dev/check_parameters.php /path/to/your/sources/ 111 112 113Examples 114-------- 115/* Gets a long, a string and its length, and a zval */ 116long l; 117char *s; 118int s_len; 119zval *param; 120if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "lsz", 121 &l, &s, &s_len, ¶m) == FAILURE) { 122 return; 123} 124 125 126/* Gets an object of class specified by my_ce, and an optional double. */ 127zval *obj; 128double d = 0.5; 129zend_class_entry *my_ce; 130if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "O|d", 131 &obj, my_ce, &d) == FAILURE) { 132 return; 133} 134 135 136/* Gets an object or null, and an array. 137 If null is passed for object, obj will be set to NULL. */ 138zval *obj; 139zval *arr; 140if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "o!a", 141 &obj, &arr) == FAILURE) { 142 return; 143} 144 145 146/* Gets a separated array which can also be null. */ 147zval *arr; 148if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a/!", 149 &arr) == FAILURE) { 150 return; 151} 152 153/* Get either a set of 3 longs or a string. */ 154long l1, l2, l3; 155char *s; 156/* 157 * The function expects a pointer to a integer in this case, not a long 158 * or any other type. If you specify a type which is larger 159 * than a 'int', the upper bits might not be initialized 160 * properly, leading to random crashes on platforms like 161 * Tru64 or Linux/Alpha. 162 */ 163int length; 164 165if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC, 166 "lll", &l1, &l2, &l3) == SUCCESS) { 167 /* manipulate longs */ 168} else if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC, 169 "s", &s, &length) == SUCCESS) { 170 /* manipulate string */ 171} else { 172 /* output error */ 173 174 return; 175} 176 177 178/* Function that accepts only varargs (0 or more) */ 179 180int i, num_varargs; 181zval ***varargs = NULL; 182 183 184if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "*", &varargs, &num_varargs) == FAILURE) { 185 return; 186} 187 188for (i = 0; i < num_varargs; i++) { 189 /* do something with varargs[i] */ 190} 191 192if (varargs) { 193 efree(varargs); 194} 195 196 197/* Function that accepts a string, followed by varargs (1 or more) */ 198 199char *str; 200int str_len; 201int i, num_varargs; 202zval ***varargs = NULL; 203 204if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s+", &str, &str_len, &varargs, &num_varargs) == FAILURE) { 205 return; 206} 207 208for (i = 0; i < num_varargs; i++) { 209 /* do something with varargs[i] */ 210} 211 212if (varargs) { 213 efree(varargs); 214} 215 216 217/* Function that takes an array, followed by varargs, and ending with a long */ 218long num; 219zval *array; 220int i, num_varargs; 221zval ***varargs = NULL; 222 223if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a*l", &array, &varargs, &num_varargs, &num) == FAILURE) { 224 return; 225} 226 227for (i = 0; i < num_varargs; i++) { 228 /* do something with varargs[i] */ 229} 230 231if (varargs) { 232 efree(varargs); 233} 234 235
