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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:22:09 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:22:09 +0000 |
commit | 43a97878ce14b72f0981164f87f2e35e14151312 (patch) | |
tree | 620249daf56c0258faa40cbdcf9cfba06de2a846 /third_party/pipewire/spa/utils/hook.h | |
parent | Initial commit. (diff) | |
download | firefox-43a97878ce14b72f0981164f87f2e35e14151312.tar.xz firefox-43a97878ce14b72f0981164f87f2e35e14151312.zip |
Adding upstream version 110.0.1.upstream/110.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/pipewire/spa/utils/hook.h')
-rw-r--r-- | third_party/pipewire/spa/utils/hook.h | 471 |
1 files changed, 471 insertions, 0 deletions
diff --git a/third_party/pipewire/spa/utils/hook.h b/third_party/pipewire/spa/utils/hook.h new file mode 100644 index 0000000000..9b1a50b63b --- /dev/null +++ b/third_party/pipewire/spa/utils/hook.h @@ -0,0 +1,471 @@ +/* Simple Plugin API + * + * Copyright © 2018 Wim Taymans + * + * 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. + */ + +#ifndef SPA_HOOK_H +#define SPA_HOOK_H + +#ifdef __cplusplus +extern "C" { +#endif + +#include <spa/utils/defs.h> +#include <spa/utils/list.h> + +/** \defgroup spa_interfaces Interfaces + * + * \brief Generic implementation of implementation-independent interfaces + * + * A SPA Interface is a generic struct that, together with a few macros, + * provides a generic way of invoking methods on objects without knowing the + * details of the implementation. + * + * The primary interaction with interfaces is through macros that expand into + * the right method call. For the implementation of an interface, we need two + * structs and a macro to invoke the `bar` method: + * + * \code{.c} + * // this struct must be public and defines the interface to a + * // struct foo + * struct foo_methods { + * uint32_t version; + * void (*bar)(void *object, const char *msg); + * }; + * + * // this struct does not need to be public + * struct foo { + * struct spa_interface iface; // must be first element, see foo_bar() + * int some_other_field; + * ... + * }; + * + * // if struct foo is private, we need to cast to a + * // generic spa_interface object + * #define foo_bar(obj, ...) ({ \ + * struct foo *f = obj; + * spa_interface_call((struct spa_interface *)f, // pointer to spa_interface in foo + * struct foo_methods, // type of callbacks + * bar, // name of methods + * 0, // hardcoded version to match foo_methods->version + * __VA_ARGS__ // pass rest of args through + * );/ + * }) + * \endcode + * + * The `struct foo_methods` and the invocation macro `foo_bar()` must be + * available to the caller. The implementation of `struct foo` can be private. + * + * \code{.c} + * void main(void) { + * struct foo *myfoo = get_foo_from_somewhere(); + * foo_bar(myfoo, "Invoking bar() on myfoo"); + * } + * \endcode + * The expansion of `foo_bar()` resolves roughly into this code: + * \code{.c} + * void main(void) { + * struct foo *myfoo = get_foo_from_somewhere(); + * // foo_bar(myfoo, "Invoking bar() on myfoo"); + * const struct foo_methods *methods = ((struct spa_interface*)myfoo)->cb; + * if (0 >= methods->version && // version check + * methods->bar) // compile error if this function does not exist, + * methods->bar(myfoo, "Invoking bar() on myfoo"); + * } + * \endcode + * + * The typecast used in `foo_bar()` allows `struct foo` to be opaque to the + * caller. The implementation may assign the callback methods at object + * instantiation, and the caller will transparently invoke the method on the + * given object. For example, the following code assigns a different `bar()` method on + * Mondays - the caller does not need to know this. + * \code{.c} + * + * static void bar_stdout(struct foo *f, const char *msg) { + * printf(msg); + * } + * static void bar_stderr(struct foo *f, const char *msg) { + * fprintf(stderr, msg); + * } + * + * struct foo* get_foo_from_somewhere() { + * struct foo *f = calloc(sizeof struct foo); + * // illustrative only, use SPA_INTERFACE_INIT() + * f->iface->cb = (struct foo_methods*) { .bar = bar_stdout }; + * if (today_is_monday) + * f->iface->cb = (struct foo_methods*) { .bar = bar_stderr }; + * return f; + * } + * \endcode + */ + +/** + * \addtogroup spa_interfaces + * \{ + */ + +/** \struct spa_callbacks + * Callbacks, contains the structure with functions and the data passed + * to the functions. The structure should also contain a version field that + * is checked. */ +struct spa_callbacks { + const void *funcs; + void *data; +}; + +/** Check if a callback \a c is of at least version \a v */ +#define SPA_CALLBACK_VERSION_MIN(c,v) ((c) && ((v) == 0 || (c)->version > (v)-1)) + +/** Check if a callback \a c has method \a m of version \a v */ +#define SPA_CALLBACK_CHECK(c,m,v) (SPA_CALLBACK_VERSION_MIN(c,v) && (c)->m) + +/** + * Initialize the set of functions \a funcs as a \ref spa_callbacks, together + * with \a _data. + */ +#define SPA_CALLBACKS_INIT(_funcs,_data) (struct spa_callbacks){ _funcs, _data, } + +/** \struct spa_interface + */ +struct spa_interface { + const char *type; + uint32_t version; + struct spa_callbacks cb; +}; + +/** + * Initialize a \ref spa_interface. + * + * \code{.c} + * const static struct foo_methods foo_funcs = { + * .bar = some_bar_implementation, + * }; + * + * struct foo *f = malloc(...); + * f->iface = SPA_INTERFACE_INIT("foo type", 0, foo_funcs, NULL); + * \endcode + * + */ +#define SPA_INTERFACE_INIT(_type,_version,_funcs,_data) \ + (struct spa_interface){ _type, _version, SPA_CALLBACKS_INIT(_funcs,_data), } + +/** + * Invoke method named \a method in the \a callbacks. + * The \a method_type defines the type of the method struct. + * Returns true if the method could be called, false otherwise. + */ +#define spa_callbacks_call(callbacks,type,method,vers,...) \ +({ \ + const type *_f = (const type *) (callbacks)->funcs; \ + bool _res = SPA_CALLBACK_CHECK(_f,method,vers); \ + if (SPA_LIKELY(_res)) \ + _f->method((callbacks)->data, ## __VA_ARGS__); \ + _res; \ +}) + +/** + * True if the \a callbacks are of version \a vers, false otherwise + */ +#define spa_callback_version_min(callbacks,type,vers) \ +({ \ + const type *_f = (const type *) (callbacks)->funcs; \ + SPA_CALLBACK_VERSION_MIN(_f,vers); \ +}) + +/** + * True if the \a callbacks contains \a method of version + * \a vers, false otherwise + */ +#define spa_callback_check(callbacks,type,method,vers) \ +({ \ + const type *_f = (const type *) (callbacks)->funcs; \ + SPA_CALLBACK_CHECK(_f,method,vers); \ +}) + +/** + * Invoke method named \a method in the \a callbacks. + * The \a method_type defines the type of the method struct. + * + * The return value is stored in \a res. + */ +#define spa_callbacks_call_res(callbacks,type,res,method,vers,...) \ +({ \ + const type *_f = (const type *) (callbacks)->funcs; \ + if (SPA_LIKELY(SPA_CALLBACK_CHECK(_f,method,vers))) \ + res = _f->method((callbacks)->data, ## __VA_ARGS__); \ + res; \ +}) + +/** + * True if the \a iface's callbacks are of version \a vers, false otherwise + */ +#define spa_interface_callback_version_min(iface,method_type,vers) \ + spa_callback_version_min(&(iface)->cb, method_type, vers) + +/** + * True if the \a iface's callback \a method is of version \a vers + * and exists, false otherwise + */ +#define spa_interface_callback_check(iface,method_type,method,vers) \ + spa_callback_check(&(iface)->cb, method_type, method, vers) + +/** + * Invoke method named \a method in the callbacks on the given interface object. + * The \a method_type defines the type of the method struct, not the interface + * itself. + */ +#define spa_interface_call(iface,method_type,method,vers,...) \ + spa_callbacks_call(&(iface)->cb,method_type,method,vers,##__VA_ARGS__) + +/** + * Invoke method named \a method in the callbacks on the given interface object. + * The \a method_type defines the type of the method struct, not the interface + * itself. + * + * The return value is stored in \a res. + */ +#define spa_interface_call_res(iface,method_type,res,method,vers,...) \ + spa_callbacks_call_res(&(iface)->cb,method_type,res,method,vers,##__VA_ARGS__) + +/** + * \} + */ + +/** \defgroup spa_hooks Hooks + * + * A SPA Hook is a data structure to keep track of callbacks. It is similar to + * the \ref spa_interfaces and typically used where an implementation allows + * for multiple external callback functions. For example, an implementation may + * use a hook list to implement signals with each caller using a hook to + * register callbacks to be invoked on those signals. + * + * The below (pseudo)code is a minimal example outlining the use of hooks: + * \code{.c} + * // the public interface + * #define VERSION_BAR_EVENTS 0 // version of the vtable + * struct bar_events { + * uint32_t version; // NOTE: an integral member named `version` + * // must be present in the vtable + * void (*boom)(void *data, const char *msg); + * }; + * + * // private implementation + * struct party { + * struct spa_hook_list bar_list; + * }; + * + * void party_add_event_listener(struct party *p, struct spa_hook *listener, + * const struct bar_events *events, void *data) + * { + * spa_hook_list_append(&p->bar_list, listener, events, data); + * } + * + * static void party_on(struct party *p) + * { + * // NOTE: this is a macro, it evaluates to an integer, + * // which is the number of hooks called + * spa_hook_list_call(&p->list, + * struct bar_events, // vtable type + * boom, // function name + * 0, // hardcoded version, + * // usually the version in which `boom` + * // has been added to the vtable + * "party on, wayne" // function argument(s) + * ); + * } + * \endcode + * + * In the caller, the hooks can be used like this: + * \code{.c} + * static void boom_cb(void *data, const char *msg) { + * // data is userdata from main() + * printf("%s", msg); + * } + * + * static const struct bar_events events = { + * .version = VERSION_BAR_EVENTS, // version of the implemented interface + * .boom = boom_cb, + * }; + * + * void main(void) { + * void *userdata = whatever; + * struct spa_hook hook; + * struct party *p = start_the_party(); + * + * party_add_event_listener(p, &hook, &events, userdata); + * + * mainloop(); + * return 0; + * } + * + * \endcode + */ + +/** + * \addtogroup spa_hooks + * \{ + */ + +/** \struct spa_hook_list + * A list of hooks. This struct is primarily used by + * implementation that use multiple caller-provided \ref spa_hook. */ +struct spa_hook_list { + struct spa_list list; +}; + + +/** \struct spa_hook + * A hook, contains the structure with functions and the data passed + * to the functions. + * + * A hook should be treated as opaque by the caller. + */ +struct spa_hook { + struct spa_list link; + struct spa_callbacks cb; + /** callback and data for the hook list, private to the + * hook_list implementor */ + void (*removed) (struct spa_hook *hook); + void *priv; +}; + +/** Initialize a hook list to the empty list*/ +static inline void spa_hook_list_init(struct spa_hook_list *list) +{ + spa_list_init(&list->list); +} + +static inline bool spa_hook_list_is_empty(struct spa_hook_list *list) +{ + return spa_list_is_empty(&list->list); +} + +/** Append a hook. */ +static inline void spa_hook_list_append(struct spa_hook_list *list, + struct spa_hook *hook, + const void *funcs, void *data) +{ + spa_zero(*hook); + hook->cb = SPA_CALLBACKS_INIT(funcs, data); + spa_list_append(&list->list, &hook->link); +} + +/** Prepend a hook */ +static inline void spa_hook_list_prepend(struct spa_hook_list *list, + struct spa_hook *hook, + const void *funcs, void *data) +{ + spa_zero(*hook); + hook->cb = SPA_CALLBACKS_INIT(funcs, data); + spa_list_prepend(&list->list, &hook->link); +} + +/** Remove a hook */ +static inline void spa_hook_remove(struct spa_hook *hook) +{ + spa_list_remove(&hook->link); + if (hook->removed) + hook->removed(hook); +} + +/** Remove all hooks from the list */ +static inline void spa_hook_list_clean(struct spa_hook_list *list) +{ + struct spa_hook *h; + spa_list_consume(h, &list->list, link) + spa_hook_remove(h); +} + +static inline void +spa_hook_list_isolate(struct spa_hook_list *list, + struct spa_hook_list *save, + struct spa_hook *hook, + const void *funcs, void *data) +{ + /* init save list and move hooks to it */ + spa_hook_list_init(save); + spa_list_insert_list(&save->list, &list->list); + /* init hooks and add single hook */ + spa_hook_list_init(list); + spa_hook_list_append(list, hook, funcs, data); +} + +static inline void +spa_hook_list_join(struct spa_hook_list *list, + struct spa_hook_list *save) +{ + spa_list_insert_list(&list->list, &save->list); +} + +#define spa_hook_list_call_simple(l,type,method,vers,...) \ +({ \ + struct spa_hook_list *_l = l; \ + struct spa_hook *_h, *_t; \ + spa_list_for_each_safe(_h, _t, &_l->list, link) \ + spa_callbacks_call(&_h->cb,type,method,vers, ## __VA_ARGS__); \ +}) + +/** Call all hooks in a list, starting from the given one and optionally stopping + * after calling the first non-NULL function, returns the number of methods + * called */ +#define spa_hook_list_do_call(l,start,type,method,vers,once,...) \ +({ \ + struct spa_hook_list *_list = l; \ + struct spa_list *_s = start ? (struct spa_list *)start : &_list->list; \ + struct spa_hook _cursor = { 0 }, *_ci; \ + int _count = 0; \ + spa_list_cursor_start(_cursor, _s, link); \ + spa_list_for_each_cursor(_ci, _cursor, &_list->list, link) { \ + if (spa_callbacks_call(&_ci->cb,type,method,vers, ## __VA_ARGS__)) { \ + _count++; \ + if (once) \ + break; \ + } \ + } \ + spa_list_cursor_end(_cursor, link); \ + _count; \ +}) + +/** + * Call the method named \a m for each element in list \a l. + * \a t specifies the type of the callback struct. + */ +#define spa_hook_list_call(l,t,m,v,...) spa_hook_list_do_call(l,NULL,t,m,v,false,##__VA_ARGS__) +/** + * Call the method named \a m for each element in list \a l, stopping after + * the first invocation. + * \a t specifies the type of the callback struct. + */ +#define spa_hook_list_call_once(l,t,m,v,...) spa_hook_list_do_call(l,NULL,t,m,v,true,##__VA_ARGS__) + +#define spa_hook_list_call_start(l,s,t,m,v,...) spa_hook_list_do_call(l,s,t,m,v,false,##__VA_ARGS__) +#define spa_hook_list_call_once_start(l,s,t,m,v,...) spa_hook_list_do_call(l,s,t,m,v,true,##__VA_ARGS__) + +/** + * \} + */ + +#ifdef __cplusplus +} +#endif + +#endif /* SPA_HOOK_H */ |