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/*
* This an unstable interface of wlroots. No guarantees are made regarding the
* future consistency of this API.
*/
#ifndef WLR_USE_UNSTABLE
#error "Add -DWLR_USE_UNSTABLE to enable unstable wlroots features"
#endif
#ifndef WLR_BACKEND_H
#define WLR_BACKEND_H
#include <wayland-server-core.h>
#include <wlr/types/wlr_output.h>
struct wlr_session;
struct wlr_backend_impl;
/**
* Per-output state for wlr_backend_test() and wlr_backend_commit().
*/
struct wlr_backend_output_state {
struct wlr_output *output;
struct wlr_output_state base;
};
/**
* A backend provides a set of input and output devices.
*
* Buffer capabilities and features can change over the lifetime of a backend,
* for instance when a child backend is added to a multi-backend.
*/
struct wlr_backend {
const struct wlr_backend_impl *impl;
// Bitfield of supported buffer capabilities (see enum wlr_buffer_cap)
uint32_t buffer_caps;
struct {
// Whether wait/signal timelines are supported in output commits
bool timeline;
} features;
struct {
/** Raised when destroyed */
struct wl_signal destroy;
/** Raised when new inputs are added, passed the struct wlr_input_device */
struct wl_signal new_input;
/** Raised when new outputs are added, passed the struct wlr_output */
struct wl_signal new_output;
} events;
};
/**
* Automatically initializes the most suitable backend given the environment.
* Will always return a multi-backend. The backend is created but not started.
* Returns NULL on failure.
*
* If session_ptr is not NULL, it's populated with the session which has been
* created with the backend, if any.
*
* The multi-backend will be destroyed if one of the primary underlying
* backends is destroyed (e.g. if the primary DRM device is unplugged).
*/
struct wlr_backend *wlr_backend_autocreate(struct wl_event_loop *loop,
struct wlr_session **session_ptr);
/**
* Start the backend. This may signal new_input or new_output immediately, but
* may also wait until the event loop is started. Returns false on failure.
*/
bool wlr_backend_start(struct wlr_backend *backend);
/**
* Destroy the backend and clean up all of its resources. Normally called
* automatically when the event loop is destroyed.
*/
void wlr_backend_destroy(struct wlr_backend *backend);
/**
* Returns the DRM node file descriptor used by the backend's underlying
* platform. Can be used by consumers for additional rendering operations.
* The consumer must not close the file descriptor since the backend continues
* to have ownership of it.
*/
int wlr_backend_get_drm_fd(struct wlr_backend *backend);
/**
* Atomically test a new configuration for multiple outputs.
*
* Some backends (e.g. DRM) have global backend-wide limitations. This function
* can be used to check whether changes across multiple outputs are supported by
* the backend.
*/
bool wlr_backend_test(struct wlr_backend *backend,
const struct wlr_backend_output_state *states, size_t states_len);
/**
* Atomically apply a new configuration for multiple outputs.
*
* There is no guarantee that the changes will be applied atomically. Users
* should call wlr_backend_test() first to check that the new state is supported
* by the backend.
*/
bool wlr_backend_commit(struct wlr_backend *backend,
const struct wlr_backend_output_state *states, size_t states_len);
#endif
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