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235 lines
7.5 KiB
Plaintext
235 lines
7.5 KiB
Plaintext
New parameter parsing functions
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===============================
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It should be easier to parse input parameters to an extension function.
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Hence, borrowing from Python's example, there are now a set of functions
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that given the string of type specifiers, can parse the input parameters
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and store the results in the user specified variables. This avoids most
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of the IS_* checks and convert_to_* conversions. The functions also
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check for the appropriate number of parameters, and try to output
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meaningful error messages.
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Prototypes
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----------
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/* Implemented. */
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int zend_parse_parameters(int num_args TSRMLS_DC, char *type_spec, ...);
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int zend_parse_parameters_ex(int flags, int num_args TSRMLS_DC, char *type_spec, ...);
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The zend_parse_parameters() function takes the number of parameters
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passed to the extension function, the type specifier string, and the
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list of pointers to variables to store the results in. The _ex() version
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also takes 'flags' argument -- current only ZEND_PARSE_PARAMS_QUIET can
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be used as 'flags' to specify that the function should operate quietly
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and not output any error messages.
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Both functions return SUCCESS or FAILURE depending on the result.
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The auto-conversions are performed as necessary. Arrays, objects, and
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resources cannot be auto-converted.
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PHP 5.5 includes a new function:
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int zend_parse_parameter(int flags, int arg_num TSRMLS_DC, zval **arg, const char *spec, ...);
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This function behaves like zend_parse_parameters_ex() except that instead of
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reading the arguments from the stack, it receives a single zval to convert
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(passed with double indirection). The passed zval may be changed in place as
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part of the conversion process.
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See also https://wiki.php.net/rfc/zpp_improv#expose_zend_parse_arg_as_zend_parse_parameter
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Type specifiers
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---------------
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The following list shows the type specifier, its meaning and the parameter
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types that need to be passed by address. All passed paramaters are set
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if the PHP parameter is non optional and untouched if optional and the
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parameter is not present. The only exception is O where the zend_class_entry*
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has to be provided on input and is used to verify the PHP parameter is an
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instance of that class.
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a - array (zval*)
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A - array or object (zval *)
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b - boolean (zend_bool)
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C - class (zend_class_entry*)
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d - double (double)
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f - function or array containing php method call info (returned as
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zend_fcall_info and zend_fcall_info_cache)
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h - array (returned as HashTable*)
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H - array or HASH_OF(object) (returned as HashTable*)
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l - long (long)
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L - long, limits out-of-range numbers to LONG_MAX/LONG_MIN (long)
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o - object of any type (zval*)
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O - object of specific type given by class entry (zval*, zend_class_entry)
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p - valid path (string without null bytes in the middle) and its length (char*, int)
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r - resource (zval*)
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s - string (with possible null bytes) and its length (char*, int)
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z - the actual zval (zval*)
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Z - the actual zval (zval**)
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* - variable arguments list (0 or more)
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+ - variable arguments list (1 or more)
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The following characters also have a meaning in the specifier string:
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| - indicates that the remaining parameters are optional, they
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should be initialized to default values by the extension since they
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will not be touched by the parsing function if they are not
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passed to it.
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/ - use SEPARATE_ZVAL_IF_NOT_REF() on the parameter it follows
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! - the parameter it follows can be of specified type or NULL. If NULL is
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passed and the output for such type is a pointer, then the output
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pointer is set to a native NULL pointer.
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For 'b', 'l' and 'd', an extra argument of type zend_bool* must be
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passed after the corresponding bool*, long* or double* arguments,
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respectively. A non-zero value will be written to the zend_bool iif a
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PHP NULL is passed.
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Note on 64bit compatibility
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---------------------------
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Please do not forget that int and long are two different things on 64bit
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OSes (int is 4 bytes and long is 8 bytes), so make sure you pass longs to "l"
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and ints to strings length (i.e. for "s" you need to pass char * and int),
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not the other way round!
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Remember: "l" is the only case when you need to pass long (and that's why
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it's "l", not "i" btw).
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Both mistakes cause memory corruptions and segfaults on 64bit OSes:
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1)
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char *str;
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long str_len; /* XXX THIS IS WRONG!! Use int instead. */
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zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len)
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2)
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int num; /* XXX THIS IS WRONG!! Use long instead. */
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zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &num)
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If you're in doubt, use check_parameters.php script to the parameters
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and their types (it can be found in ./scripts/dev/ directory of PHP sources):
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# php ./scripts/dev/check_parameters.php /path/to/your/sources/
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Examples
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--------
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/* Gets a long, a string and its length, and a zval */
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long l;
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char *s;
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int s_len;
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zval *param;
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if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "lsz",
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&l, &s, &s_len, ¶m) == FAILURE) {
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return;
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}
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/* Gets an object of class specified by my_ce, and an optional double. */
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zval *obj;
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double d = 0.5;
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zend_class_entry *my_ce;
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if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "O|d",
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&obj, my_ce, &d) == FAILURE) {
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return;
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}
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/* Gets an object or null, and an array.
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If null is passed for object, obj will be set to NULL. */
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zval *obj;
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zval *arr;
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if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "o!a",
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&obj, &arr) == FAILURE) {
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return;
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}
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/* Gets a separated array which can also be null. */
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zval *arr;
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if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a/!",
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&arr) == FAILURE) {
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return;
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}
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/* Get either a set of 3 longs or a string. */
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long l1, l2, l3;
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char *s;
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/*
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* The function expects a pointer to a integer in this case, not a long
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* or any other type. If you specify a type which is larger
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* than a 'int', the upper bits might not be initialized
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* properly, leading to random crashes on platforms like
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* Tru64 or Linux/Alpha.
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*/
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int length;
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if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC,
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"lll", &l1, &l2, &l3) == SUCCESS) {
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/* manipulate longs */
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} else if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC,
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"s", &s, &length) == SUCCESS) {
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/* manipulate string */
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} else {
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/* output error */
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return;
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}
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/* Function that accepts only varargs (0 or more) */
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int i, num_varargs;
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zval ***varargs = NULL;
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if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "*", &varargs, &num_varargs) == FAILURE) {
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return;
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}
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for (i = 0; i < num_varargs; i++) {
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/* do something with varargs[i] */
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}
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if (varargs) {
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efree(varargs);
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}
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/* Function that accepts a string, followed by varargs (1 or more) */
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char *str;
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int str_len;
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int i, num_varargs;
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zval ***varargs = NULL;
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if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s+", &str, &str_len, &varargs, &num_varargs) == FAILURE) {
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return;
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}
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for (i = 0; i < num_varargs; i++) {
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/* do something with varargs[i] */
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}
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if (varargs) {
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efree(varargs);
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}
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/* Function that takes an array, followed by varargs, and ending with a long */
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long num;
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zval *array;
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int i, num_varargs;
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zval ***varargs = NULL;
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if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a*l", &array, &varargs, &num_varargs, &num) == FAILURE) {
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return;
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}
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for (i = 0; i < num_varargs; i++) {
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/* do something with varargs[i] */
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}
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if (varargs) {
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efree(varargs);
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}
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