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    1: New parameter parsing functions
    2: ===============================
    3: 
    4: It should be easier to parse input parameters to an extension function.
    5: Hence, borrowing from Python's example, there are now a set of functions
    6: that given the string of type specifiers, can parse the input parameters
    7: and store the results in the user specified variables. This avoids most
    8: of the IS_* checks and convert_to_* conversions. The functions also
    9: check for the appropriate number of parameters, and try to output
   10: meaningful error messages.
   11: 
   12: 
   13: Prototypes
   14: ----------
   15: /* Implemented. */
   16: int zend_parse_parameters(int num_args TSRMLS_DC, char *type_spec, ...);
   17: int zend_parse_parameters_ex(int flags, int num_args TSRMLS_DC, char *type_spec, ...);
   18: 
   19: The zend_parse_parameters() function takes the number of parameters
   20: passed to the extension function, the type specifier string, and the
   21: list of pointers to variables to store the results in. The _ex() version
   22: also takes 'flags' argument -- current only ZEND_PARSE_PARAMS_QUIET can
   23: be used as 'flags' to specify that the function should operate quietly
   24: and not output any error messages.
   25: 
   26: Both functions return SUCCESS or FAILURE depending on the result.
   27: 
   28: The auto-conversions are performed as necessary. Arrays, objects, and
   29: resources cannot be auto-converted.
   30: 
   31: 
   32: Type specifiers
   33: ---------------
   34:  The following list shows the type specifier, its meaning and the parameter 
   35:  types that need to be passed by address. All passed paramaters are set
   36:  if the PHP parameter is non optional and untouched if optional and the 
   37:  parameter is not present. The only exception is O where the zend_class_entry*
   38:  has to be provided on input and is used to verify the PHP parameter is an 
   39:  instance of that class.
   40: 
   41:  a  - array (zval*)
   42:  A  - array or object (zval *)
   43:  b  - boolean (zend_bool)
   44:  C  - class (zend_class_entry*)
   45:  d  - double (double)
   46:  f  - function or array containing php method call info (returned as 
   47:       zend_fcall_info and zend_fcall_info_cache)
   48:  h  - array (returned as HashTable*)
   49:  H  - array or HASH_OF(object) (returned as HashTable*)
   50:  l  - long (long)
   51:  L  - long, limits out-of-range numbers to LONG_MAX/LONG_MIN (long)
   52:  o  - object of any type (zval*)
   53:  O  - object of specific type given by class entry (zval*, zend_class_entry)
   54:  r  - resource (zval*)
   55:  s  - string (with possible null bytes) and its length (char*, int)
   56:  z  - the actual zval (zval*)
   57:  Z  - the actual zval (zval**)
   58:  *  - variable arguments list (0 or more)
   59:  +  - variable arguments list (1 or more)
   60: 
   61:  The following characters also have a meaning in the specifier string:
   62:     | - indicates that the remaining parameters are optional, they
   63:         should be initialized to default values by the extension since they
   64:         will not be touched by the parsing function if they are not
   65:         passed to it.
   66:     / - use SEPARATE_ZVAL_IF_NOT_REF() on the parameter it follows
   67:     ! - the parameter it follows can be of specified type or NULL (applies
   68: 		to all specifiers except for 'b', 'l', and 'd'). If NULL is passed, the
   69: 		results pointer is set to NULL as well.
   70: 
   71: 
   72: Note on 64bit compatibility
   73: ---------------------------
   74: Please do not forget that int and long are two different things on 64bit 
   75: OSes (int is 4 bytes and long is 8 bytes), so make sure you pass longs to "l" 
   76: and ints to strings length (i.e. for "s" you need to pass char * and int), 
   77: not the other way round!
   78: Remember: "l" is the only case when you need to pass long (and that's why 
   79: it's "l", not "i" btw).
   80: 
   81: Both mistakes cause memory corruptions and segfaults on 64bit OSes:
   82: 1)
   83:   char *str;
   84:   long str_len; /* XXX THIS IS WRONG!! Use int instead. */
   85:   zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len)
   86: 
   87: 2)
   88:   int num; /* XXX THIS IS WRONG!! Use long instead. */
   89:   zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &num)
   90: 
   91: If you're in doubt, use check_parameters.php script to the parameters 
   92: and their types (it can be found in ./scripts/dev/ directory of PHP sources):
   93: 
   94: # php ./scripts/dev/check_parameters.php /path/to/your/sources/
   95: 
   96: 
   97: Examples
   98: --------
   99: /* Gets a long, a string and its length, and a zval */
  100: long l;
  101: char *s;
  102: int s_len;
  103: zval *param;
  104: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "lsz",
  105:                           &l, &s, &s_len, &param) == FAILURE) {
  106:     return;
  107: }
  108: 
  109: 
  110: /* Gets an object of class specified by my_ce, and an optional double. */
  111: zval *obj;
  112: double d = 0.5;
  113: zend_class_entry *my_ce;
  114: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "O|d",
  115:                           &obj, my_ce, &d) == FAILURE) {
  116:     return;
  117: }
  118: 
  119: 
  120: /* Gets an object or null, and an array.
  121:    If null is passed for object, obj will be set to NULL. */
  122: zval *obj;
  123: zval *arr;
  124: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "o!a",
  125:                           &obj, &arr) == FAILURE) {
  126:     return;
  127: }
  128: 
  129: 
  130: /* Gets a separated array which can also be null. */
  131: zval *arr;
  132: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a/!",
  133:                           &arr) == FAILURE) {
  134:     return;
  135: }
  136: 
  137: /* Get either a set of 3 longs or a string. */
  138: long l1, l2, l3;
  139: char *s;
  140: /* 
  141:  * The function expects a pointer to a integer in this case, not a long
  142:  * or any other type.  If you specify a type which is larger
  143:  * than a 'int', the upper bits might not be initialized
  144:  * properly, leading to random crashes on platforms like
  145:  * Tru64 or Linux/Alpha.
  146:  */
  147: int length;
  148: 
  149: if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC,
  150:                              "lll", &l1, &l2, &l3) == SUCCESS) {
  151:     /* manipulate longs */
  152: } else if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC,
  153:                                     "s", &s, &length) == SUCCESS) {
  154:     /* manipulate string */
  155: } else {
  156:     /* output error */
  157: 
  158:     return;
  159: }
  160: 
  161: 
  162: /* Function that accepts only varargs (0 or more) */
  163: 
  164: int i, num_varargs;
  165: zval ***varargs = NULL;
  166: 
  167: 
  168: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "*", &varargs, &num_varargs) == FAILURE) {
  169:     return;
  170: }
  171: 
  172: for (i = 0; i < num_varargs; i++) {
  173:     /* do something with varargs[i] */
  174: }
  175: 
  176: if (varargs) {
  177:     efree(varargs);
  178: }
  179: 
  180: 
  181: /* Function that accepts a string, followed by varargs (1 or more) */
  182: 
  183: char *str;
  184: int str_len;
  185: int i, num_varargs;
  186: zval ***varargs = NULL;
  187: 
  188: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s+", &str, &str_len, &varargs, &num_varargs) == FAILURE) {
  189:     return;
  190: }
  191: 
  192: for (i = 0; i < num_varargs; i++) {
  193:     /* do something with varargs[i] */
  194: }
  195: 
  196: if (varargs) {
  197:     efree(varargs);
  198: }
  199: 
  200: 
  201: /* Function that takes an array, followed by varargs, and ending with a long */
  202: long num;
  203: zval *array;
  204: int i, num_varargs;
  205: zval ***varargs = NULL;
  206: 
  207: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a*l", &array, &varargs, &num_varargs, &num) == FAILURE) {
  208:     return;
  209: }
  210: 
  211: for (i = 0; i < num_varargs; i++) {
  212:     /* do something with varargs[i] */
  213: }
  214: 
  215: if (varargs) {
  216:     efree(varargs);
  217: }
  218: