pkgconf/doc/libpkgconf-tuple.rst

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libpkgconf `tuple` module
=========================
The `tuple` module provides key-value mappings backed by a linked list. The key-value
mapping is mainly used for variable substitution when parsing .pc files.
There are two sets of mappings: a ``pkgconf_pkg_t`` specific mapping, and a `global` mapping.
The `tuple` module provides convenience wrappers for managing the `global` mapping, which is
attached to a given client object.
.. c:function:: void pkgconf_tuple_add_global(pkgconf_client_t *client, const char *key, const char *value)
Defines a global variable, replacing the previous declaration if one was set.
:param pkgconf_client_t* client: The pkgconf client object to modify.
:param char* key: The key for the mapping (variable name).
:param char* value: The value for the mapped entry.
:return: nothing
.. c:function:: void pkgconf_tuple_find_global(const pkgconf_client_t *client, const char *key)
Looks up a global variable.
:param pkgconf_client_t* client: The pkgconf client object to access.
:param char* key: The key or variable name to look up.
:return: the contents of the variable or ``NULL``
:rtype: char *
.. c:function:: void pkgconf_tuple_free_global(pkgconf_client_t *client)
Delete all global variables associated with a pkgconf client object.
:param pkgconf_client_t* client: The pkgconf client object to modify.
:return: nothing
.. c:function:: void pkgconf_tuple_define_global(pkgconf_client_t *client, const char *kv)
Parse and define a global variable.
:param pkgconf_client_t* client: The pkgconf client object to modify.
:param char* kv: The variable in the form of ``key=value``.
:return: nothing
.. c:function:: pkgconf_tuple_t *pkgconf_tuple_add(const pkgconf_client_t *client, pkgconf_list_t *list, const char *key, const char *value, bool parse)
Optionally parse and then define a variable.
:param pkgconf_client_t* client: The pkgconf client object to access.
:param pkgconf_list_t* list: The variable list to add the new variable to.
:param char* key: The name of the variable being added.
:param char* value: The value of the variable being added.
:param bool parse: Whether or not to parse the value for variable substitution.
:return: a variable object
:rtype: pkgconf_tuple_t *
.. c:function:: char *pkgconf_tuple_find(const pkgconf_client_t *client, pkgconf_list_t *list, const char *key)
Look up a variable in a variable list.
:param pkgconf_client_t* client: The pkgconf client object to access.
:param pkgconf_list_t* list: The variable list to search.
:param char* key: The variable name to search for.
:return: the value of the variable or ``NULL``
:rtype: char *
.. c:function:: char *pkgconf_tuple_parse(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *value)
Parse an expression for variable substitution.
:param pkgconf_client_t* client: The pkgconf client object to access.
:param pkgconf_list_t* list: The variable list to search for variables (along side the global variable list).
:param char* value: The ``key=value`` string to parse.
:return: the variable data with any variables substituted
:rtype: char *
.. c:function:: void pkgconf_tuple_free_entry(pkgconf_tuple_t *tuple, pkgconf_list_t *list)
Deletes a variable object, removing it from any variable lists and releasing any memory associated
with it.
:param pkgconf_tuple_t* tuple: The variable object to release.
:param pkgconf_list_t* list: The variable list the variable object is attached to.
:return: nothing
.. c:function:: void pkgconf_tuple_free(pkgconf_list_t *list)
Deletes a variable list and any variables attached to it.
:param pkgconf_list_t* list: The variable list to delete.
:return: nothing