/*
* Copyright © 2008 Kristian Høgsberg
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/** \file wayland-util.h
*
* \brief Utility classes, functions, and macros.
*/
#ifndef WAYLAND_UTIL_H
#define WAYLAND_UTIL_H
#include <math.h>
#include <stddef.h>
#include <inttypes.h>
#include <stdarg.h>
#ifdef __cplusplus
extern "C" {
#endif
/** Visibility attribute */
#if defined(__GNUC__) && __GNUC__ >= 4
#define WL_EXPORT __attribute__ ((visibility("default")))
#else
#define WL_EXPORT
#endif
/** Deprecated attribute */
#if defined(__GNUC__) && __GNUC__ >= 4
#define WL_DEPRECATED __attribute__ ((deprecated))
#else
#define WL_DEPRECATED
#endif
/**
* Printf-style argument attribute
*
* \param x Ordinality of the format string argument
* \param y Ordinality of the argument to check against the format string
*
* \sa https://gcc.gnu.org/onlinedocs/gcc-3.2.1/gcc/Function-Attributes.html
*/
#if defined(__GNUC__) && __GNUC__ >= 4
#define WL_PRINTF(x, y) __attribute__((__format__(__printf__, x, y)))
#else
#define WL_PRINTF(x, y)
#endif
/** \class wl_object
*
* \brief A protocol object.
*
* A `wl_object` is an opaque struct identifying the protocol object
* underlying a `wl_proxy` or `wl_resource`.
*
* \note Functions accessing a `wl_object` are not normally used by client code.
* Clients should normally use the higher level interface generated by the
* scanner to interact with compositor objects.
*
*/
struct wl_object;
/**
* Protocol message signature
*
* A wl_message describes the signature of an actual protocol message, such as a
* request or event, that adheres to the Wayland protocol wire format. The
* protocol implementation uses a wl_message within its demarshal machinery for
* decoding messages between a compositor and its clients. In a sense, a
* wl_message is to a protocol message like a class is to an object.
*
* The `name` of a wl_message is the name of the corresponding protocol message.
*
* The `signature` is an ordered list of symbols representing the data types
* of message arguments and, optionally, a protocol version and indicators for
* nullability. A leading integer in the `signature` indicates the _since_
* version of the protocol message. A `?` preceding a data type symbol indicates
* that the following argument type is nullable. While it is a protocol violation
* to send messages with non-nullable arguments set to `NULL`, event handlers in
* clients might still get called with non-nullable object arguments set to
* `NULL`. This can happen when the client destroyed the object being used as
* argument on its side and an event referencing that object was sent before the
* server knew about its destruction. As this race cannot be prevented, clients
* should - as a general rule - program their event handlers such that they can
* handle object arguments declared non-nullable being `NULL` gracefully.
*
* When no arguments accompany a message, `signature` is an empty string.
*
* Symbols:
*
* * `i`: int
* * `u`: uint
* * `f`: fixed
* * `s`: string
* * `o`: object
* * `n`: new_id
* * `a`: array
* * `h`: fd
* * `?`: following argument is nullable
*
* While demarshaling primitive arguments is straightforward, when demarshaling
* messages containing `object` or `new_id` arguments, the protocol
* implementation often must determine the type of the object. The `types` of a
* wl_message is an array of wl_interface references that correspond to `o` and
* `n` arguments in `signature`, with `NULL` placeholders for arguments with
* non-object types.
*
* Consider the protocol event wl_display `delete_id` that has a single `uint`
* argument. The wl_message is:
*
* \code
* { "delete_id", "u", [NULL] }
* \endcode
*
* Here, the message `name` is `"delete_id"`, the `signature` is `"u"`, and the
* argument `types` is `[NULL]`, indicating that the `uint` argument has no
* corresponding wl_interface since it is a primitive argument.
*
* In contrast, consider a `wl_foo` interface supporting protocol request `bar`
* that has existed since version 2, and has two arguments: a `uint` and an
* object of type `wl_baz_interface` that may be `NULL`. Such a `wl_message`
* might be:
*
* \code
* { "bar", "2u?o", [NULL, &wl_baz_interface] }
* \endcode
*
* Here, the message `name` is `"bar"`, and the `signature` is `"2u?o"`. Notice
* how the `2` indicates the protocol version, the `u` indicates the first
* argument type is `uint`, and the `?o` indicates that the second argument
* is an object that may be `NULL`. Lastly, the argument `types` array indicates
* that no wl_interface corresponds to the first argument, while the type
* `wl_baz_interface` corresponds to the second argument.
*
* \sa wl_argument
* \sa wl_interface
* \sa <a href="https://wayland.freedesktop.org/docs/html/ch04.html#sect-Protocol-Wire-Format">Wire Format</a>
*/
struct wl_message {
/** Message name */
const char *name;
/** Message signature */
const char *signature;
/** Object argument interfaces */
const struct wl_interface **types;
};
/**
* Protocol object interface
*
* A wl_interface describes the API of a protocol object defined in the Wayland
* protocol specification. The protocol implementation uses a wl_interface
* within its marshalling machinery for encoding client requests.
*
* The `name` of a wl_interface is the name of the corresponding protocol
* interface, and `version` represents the version of the interface. The members
* `method_count` and `event_count` represent the number of `methods` (requests)
* and `events` in the respective wl_message members.
*
* For example, consider a protocol interface `foo`, marked as version `1`, with
* two requests and one event.
*
* \code{.xml}
* <interface name="foo" version="1">
* <request name="a"></request>
* <request name="b"></request>
* <event name="c"></event>
* </interface>
* \endcode
*
* Given two wl_message arrays `foo_requests` and `foo_events`, a wl_interface
* for `foo` might be:
*
* \code
* struct wl_interface foo_interface = {
* "foo", 1,
* 2, foo_requests,
* 1, foo_events
* };
* \endcode
*
* \note The server side of the protocol may define interface <em>implementation
* types</em> that incorporate the term `interface` in their name. Take
* care to not confuse these server-side `struct`s with a wl_interface
* variable whose name also ends in `interface`. For example, while the
* server may define a type `struct wl_foo_interface`, the client may
* define a `struct wl_interface wl_foo_interface`.
*
* \sa wl_message
* \sa wl_proxy
* \sa <a href="https://wayland.freedesktop.org/docs/html/ch04.html#sect-Protocol-Interfaces">Interfaces</a>
* \sa <a href="https://wayland.freedesktop.org/docs/html/ch04.html#sect-Protocol-Versioning">Versioning</a>
*/
struct wl_interface {
/** Interface name */
const char *name;
/** Interface version */
int version;
/** Number of methods (requests) */
int method_count;
/** Method (request) signatures */
const struct wl_message *methods;
/** Number of events */
int event_count;
/** Event signatures */
const struct wl_message *events;
};
/** \class wl_list
*
* \brief Doubly-linked list
*
* On its own, an instance of `struct wl_list` represents the sentinel head of
* a doubly-linked list, and must be initialized using wl_list_init().
* When empty, the list head's `next` and `prev` members point to the list head
* itself, otherwise `next` references the first element in the list, and `prev`
* refers to the last element in the list.
*
* Use the `struct wl_list` type to represent both the list head and the links
* between elements within the list. Use wl_list_empty() to determine if the
* list is empty in O(1).
*
* All elements in the list must be of the same type. The element type must have
* a `struct wl_list` member, often named `link` by convention. Prior to
* insertion, there is no need to initialize an element's `link` - invoking
* wl_list_init() on an individual list element's `struct wl_list` member is
* unnecessary if the very next operation is wl_list_insert(). However, a
* common idiom is to initialize an element's `link` prior to removal - ensure
* safety by invoking wl_list_init() before wl_list_remove().
*
* Consider a list reference `struct wl_list foo_list`, an element type as
* `struct element`, and an element's link member as `struct wl_list link`.
*
* The following code initializes a list and adds three elements to it.
*
* \code
* struct wl_list foo_list;
*
* struct element {
* int foo;
* struct wl_list link;
* };
* struct element e1, e2, e3;
*
* wl_list_init(&foo_list);
* wl_list_insert(&foo_list, &e1.link); // e1 is the first element
* wl_list_insert(&foo_list, &e2.link); // e2 is now the first element
* wl_list_insert(&e2.link, &e3.link); // insert e3 after e2
* \endcode
*
* The list now looks like <em>[e2, e3, e1]</em>.
*
* The `wl_list` API provides some iterator macros. For example, to iterate
* a list in ascending order:
*
* \code
* struct element *e;
* wl_list_for_each(e, foo_list, link) {
* do_something_with_element(e);
* }
* \endcode
*
* See the documentation of each iterator for details.
* \sa http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/include/linux/list.h
*/
struct wl_list {
/** Previous list element */
struct wl_list *prev;
/** Next list element */
struct wl_list *next;
};
/**
* Initializes the list.
*
* \param list List to initialize
*
* \memberof wl_list
*/
void
wl_list_init(struct wl_list *list);
/**
* Inserts an element into the list, after the element represented by \p list.
* When \p list is a reference to the list itself (the head), set the containing
* struct of \p elm as the first element in the list.
*
* \note If \p elm is already part of a list, inserting it again will lead to
* list corruption.
*
* \param list List element after which the new element is inserted
* \param elm Link of the containing struct to insert into the list
*
* \memberof wl_list
*/
void
wl_list_insert(struct wl_list *list, struct wl_list *elm);
/**
* Removes an element from the list.
*
* \note This operation leaves \p elm in an invalid state.
*
* \param elm Link of the containing struct to remove from the list
*
* \memberof wl_list
*/
void
wl_list_remove(struct wl_list *elm);
/**
* Determines the length of the list.
*
* \note This is an O(n) operation.
*
* \param list List whose length is to be determined
*
* \return Number of elements in the list
*
* \memberof wl_list
*/
int
wl_list_length(const struct wl_list *list);
/**
* Determines if the list is empty.
*
* \param list List whose emptiness is to be determined
*
* \return 1 if empty, or 0 if not empty
*
* \memberof wl_list
*/
int
wl_list_empty(const struct wl_list *list);
/**
* Inserts all of the elements of one list into another, after the element
* represented by \p list.
*
* \note This leaves \p other in an invalid state.
*
* \param list List element after which the other list elements will be inserted
* \param other List of elements to insert
*
* \memberof wl_list
*/
void
wl_list_insert_list(struct wl_list *list, struct wl_list *other);
/**
* Retrieves a pointer to a containing struct, given a member name.
*
* This macro allows "conversion" from a pointer to a member to its containing
* struct. This is useful if you have a contained item like a wl_list,
* wl_listener, or wl_signal, provided via a callback or other means, and would
* like to retrieve the struct that contains it.
*
* To demonstrate, the following example retrieves a pointer to
* `example_container` given only its `destroy_listener` member:
*
* \code
* struct example_container {
* struct wl_listener destroy_listener;
* // other members...
* };
*
* void example_container_destroy(struct wl_listener *listener, void *data)
* {
* struct example_container *ctr;
*
* ctr = wl_container_of(listener, ctr, destroy_listener);
* // destroy ctr...
* }
* \endcode
*
* \note `sample` need not be a valid pointer. A null or uninitialised pointer
* is sufficient.
*
* \param ptr Valid pointer to the contained member
* \param sample Pointer to a struct whose type contains \p ptr
* \param member Named location of \p ptr within the \p sample type
*
* \return The container for the specified pointer
*/
#define wl_container_of(ptr, sample, member) \
(__typeof__(sample))((char *)(ptr) - \
offsetof(__typeof__(*sample), member))
/**
* Iterates over a list.
*
* This macro expresses a for-each iterator for wl_list. Given a list and
* wl_list link member name (often named `link` by convention), this macro
* assigns each element in the list to \p pos, which can then be referenced in
* a trailing code block. For example, given a wl_list of `struct message`
* elements:
*
* \code
* struct message {
* char *contents;
* wl_list link;
* };
*
* struct wl_list *message_list;
* // Assume message_list now "contains" many messages
*
* struct message *m;
* wl_list_for_each(m, message_list, link) {
* do_something_with_message(m);
* }
* \endcode
*
* \param pos Cursor that each list element will be assigned to
* \param head Head of the list to iterate over
* \param member Name of the link member within the element struct
*
* \relates wl_list
*/
#define wl_list_for_each(pos, head, member) \
for (pos = wl_container_of((head)->next, pos, member); \
&pos->member != (head); \
pos = wl_container_of(pos->member.next, pos, member))
/**
* Iterates over a list, safe against removal of the list element.
*
* \note Only removal of the current element, \p pos, is safe. Removing
* any other element during traversal may lead to a loop malfunction.
*
* \sa wl_list_for_each()
*
* \param pos Cursor that each list element will be assigned to
* \param tmp Temporary pointer of the same type as \p pos
* \param head Head of the list to iterate over
* \param member Name of the link member within the element struct
*
* \relates wl_list
*/
#define wl_list_for_each_safe(pos, tmp, head, member) \
for (pos = wl_container_of((head)->next, pos, member), \
tmp = wl_container_of((pos)->member.next, tmp, member); \
&pos->member != (head); \
pos = tmp, \
tmp = wl_container_of(pos->member.next, tmp, member))
/**
* Iterates backwards over a list.
*
* \sa wl_list_for_each()
*
* \param pos Cursor that each list element will be assigned to
* \param head Head of the list to iterate over
* \param member Name of the link member within the element struct
*
* \relates wl_list
*/
#define wl_list_for_each_reverse(pos, head, member) \
for (pos = wl_container_of((head)->prev, pos, member); \
&pos->member != (head); \
pos = wl_container_of(pos->member.prev, pos, member))
/**
* Iterates backwards over a list, safe against removal of the list element.
*
* \note Only removal of the current element, \p pos, is safe. Removing
* any other element during traversal may lead to a loop malfunction.
*
* \sa wl_list_for_each()
*
* \param pos Cursor that each list element will be assigned to
* \param tmp Temporary pointer of the same type as \p pos
* \param head Head of the list to iterate over
* \param member Name of the link member within the element struct
*
* \relates wl_list
*/
#define wl_list_for_each_reverse_safe(pos, tmp, head, member) \
for (pos = wl_container_of((head)->prev, pos, member), \
tmp = wl_container_of((pos)->member.prev, tmp, member); \
&pos->member != (head); \
pos = tmp, \
tmp = wl_container_of(pos->member.prev, tmp, member))
/**
* \class wl_array
*
* Dynamic array
*
* A wl_array is a dynamic array that can only grow until released. It is
* intended for relatively small allocations whose size is variable or not known
* in advance. While construction of a wl_array does not require all elements to
* be of the same size, wl_array_for_each() does require all elements to have
* the same type and size.
*
*/
struct wl_array {
/** Array size */
size_t size;
/** Allocated space */
size_t alloc;
/** Array data */
void *data;
};
/**
* Initializes the array.
*
* \param array Array to initialize
*
* \memberof wl_array
*/
void
wl_array_init(struct wl_array *array);
/**
* Releases the array data.
*
* \note Leaves the array in an invalid state.
*
* \param array Array whose data is to be released
*
* \memberof wl_array
*/
void
wl_array_release(struct wl_array *array);
/**
* Increases the size of the array by \p size bytes.
*
* \param array Array whose size is to be increased
* \param size Number of bytes to increase the size of the array by
*
* \return A pointer to the beginning of the newly appended space, or NULL when
* resizing fails.
*
* \memberof wl_array
*/
void *
wl_array_add(struct wl_array *array, size_t size);
/**
* Copies the contents of \p source to \p array.
*
* \param array Destination array to copy to
* \param source Source array to copy from
*
* \return 0 on success, or -1 on failure
*
* \memberof wl_array
*/
int
wl_array_copy(struct wl_array *array, struct wl_array *source);
/**
* Iterates over an array.
*
* This macro expresses a for-each iterator for wl_array. It assigns each
* element in the array to \p pos, which can then be referenced in a trailing
* code block. \p pos must be a pointer to the array element type, and all
* array elements must be of the same type and size.
*
* \param pos Cursor that each array element will be assigned to
* \param array Array to iterate over
*
* \relates wl_array
* \sa wl_list_for_each()
*/
#define wl_array_for_each(pos, array) \
for (pos = (array)->data; \
(const char *) pos < ((const char *) (array)->data + (array)->size); \
(pos)++)
/**
* Fixed-point number
*
* A `wl_fixed_t` is a 24.8 signed fixed-point number with a sign bit, 23 bits
* of integer precision and 8 bits of decimal precision. Consider `wl_fixed_t`
* as an opaque struct with methods that facilitate conversion to and from
* `double` and `int` types.
*/
typedef int32_t wl_fixed_t;
/**
* Converts a fixed-point number to a floating-point number.
*
* \param f Fixed-point number to convert
*
* \return Floating-point representation of the fixed-point argument
*/
static inline double
wl_fixed_to_double(wl_fixed_t f)
{
union {
double d;
int64_t i;
} u;
u.i = ((1023LL + 44LL) << 52) + (1LL << 51) + f;
return u.d - (3LL << 43);
}
/**
* Converts a floating-point number to a fixed-point number.
*
* \param d Floating-point number to convert
*
* \return Fixed-point representation of the floating-point argument
*/
static inline wl_fixed_t
wl_fixed_from_double(double d)
{
union {
double d;
int64_t i;
} u;
u.d = d + (3LL << (51 - 8));
return (wl_fixed_t)u.i;
}
/**
* Converts a fixed-point number to an integer.
*
* \param f Fixed-point number to convert
*
* \return Integer component of the fixed-point argument
*/
static inline int
wl_fixed_to_int(wl_fixed_t f)
{
return f / 256;
}
/**
* Converts an integer to a fixed-point number.
*
* \param i Integer to convert
*
* \return Fixed-point representation of the integer argument
*/
static inline wl_fixed_t
wl_fixed_from_int(int i)
{
return i * 256;
}
/**
* Protocol message argument data types
*
* This union represents all of the argument types in the Wayland protocol wire
* format. The protocol implementation uses wl_argument within its marshalling
* machinery for dispatching messages between a client and a compositor.
*
* \sa wl_message
* \sa wl_interface
* \sa <a href="https://wayland.freedesktop.org/docs/html/ch04.html#sect-Protocol-wire-Format">Wire Format</a>
*/
union wl_argument {
int32_t i; /**< `int` */
uint32_t u; /**< `uint` */
wl_fixed_t f; /**< `fixed` */
const char *s; /**< `string` */
struct wl_object *o; /**< `object` */
uint32_t n; /**< `new_id` */
struct wl_array *a; /**< `array` */
int32_t h; /**< `fd` */
};
/**
* Dispatcher function type alias
*
* A dispatcher is a function that handles the emitting of callbacks in client
* code. For programs directly using the C library, this is done by using
* libffi to call function pointers. When binding to languages other than C,
* dispatchers provide a way to abstract the function calling process to be
* friendlier to other function calling systems.
*
* A dispatcher takes five arguments: The first is the dispatcher-specific
* implementation associated with the target object. The second is the object
* upon which the callback is being invoked (either wl_proxy or wl_resource).
* The third and fourth arguments are the opcode and the wl_message
* corresponding to the callback. The final argument is an array of arguments
* received from the other process via the wire protocol.
*
* \param "const void *" Dispatcher-specific implementation data
* \param "void *" Callback invocation target (wl_proxy or `wl_resource`)
* \param uint32_t Callback opcode
* \param "const struct wl_message *" Callback message signature
* \param "union wl_argument *" Array of received arguments
*
* \return 0 on success, or -1 on failure
*/
typedef int (*wl_dispatcher_func_t)(const void *, void *, uint32_t,
const struct wl_message *,
union wl_argument *);
/**
* Log function type alias
*
* The C implementation of the Wayland protocol abstracts the details of
* logging. Users may customize the logging behavior, with a function conforming
* to the `wl_log_func_t` type, via `wl_log_set_handler_client` and
* `wl_log_set_handler_server`.
*
* A `wl_log_func_t` must conform to the expectations of `vprintf`, and
* expects two arguments: a string to write and a corresponding variable
* argument list. While the string to write may contain format specifiers and
* use values in the variable argument list, the behavior of any `wl_log_func_t`
* depends on the implementation.
*
* \note Take care to not confuse this with `wl_protocol_logger_func_t`, which
* is a specific server-side logger for requests and events.
*
* \param "const char *" String to write to the log, containing optional format
* specifiers
* \param "va_list" Variable argument list
*
* \sa wl_log_set_handler_client
* \sa wl_log_set_handler_server
*/
typedef void (*wl_log_func_t)(const char *, va_list) WL_PRINTF(1, 0);
/**
* Return value of an iterator function
*
* \sa wl_client_for_each_resource_iterator_func_t
* \sa wl_client_for_each_resource
*/
enum wl_iterator_result {
/** Stop the iteration */
WL_ITERATOR_STOP,
/** Continue the iteration */
WL_ITERATOR_CONTINUE
};
#ifdef __cplusplus
}
#endif
#endif
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