accessibility_provider.hpp

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#pragma once
 
// Cross-platform entry point for the OS-native accessibility provider.
//
// Each platform ships its own `accessibility_<platform>.cpp` that
// defines `init_accessibility(View&, void* native_window)`. The header
// keeps the call site cross-platform so widgets and WindowHost can
// invoke a single function; the platform TU handles the OS nuance.
//
// The "provider" concept matches the Windows UIA / Linux AT-SPI
// architecture: the OS asks the plugin window for a provider object,
// which then walks the View tree and surfaces each View's access_role /
// access_label / access_value / access_bounds to the screen reader.
//
// macOS / iOS use NSAccessibility / UIAccessibility on the view side
// directly and do not route through init_accessibility().
 
#include <cstdint>
#include <memory>
#include <string>
 
namespace pulp::view {
 
class View;

void* init_accessibility(View& root, void* native_window);

void shutdown_accessibility(void* handle);

void accessibility_tree_changed(void* handle);

void accessibility_tree_will_change(void* handle);
bool accessibility_tree_retirement_ready(void* handle);
void accessibility_retain_until_retired(void* handle,
                                        std::shared_ptr<void> owner) noexcept;

void accessibility_tree_changed(View& root);
void accessibility_tree_will_change(View& root);
bool accessibility_tree_retirement_ready(View& root);
void accessibility_retain_until_retired(View& root,
                                        std::shared_ptr<void> owner) noexcept;
 
namespace detail {
void register_accessibility_provider(View& root, void* handle);
void unregister_accessibility_provider(void* handle);
} // namespace detail

void accessibility_pump(void* handle);
 
// ── Event-raising surface ────────────────────────────────────────────────
//
// Widgets call these when their accessibility-relevant state changes so
// the platform provider can raise the matching OS event. A no-op on
// platforms that have no provider attached (or no accessibility clients
// listening). Safe to call from the UI thread — the implementation is
// cheap when no assistive tech is active.
//
// The `handle` is the opaque returned by init_accessibility().

void notify_accessibility_value_changed(void* handle, View& target);

void notify_accessibility_focus_changed(void* handle, View& target);

void notify_accessibility_name_changed(void* handle, View& target);
 
#if defined(__linux__) && !defined(__ANDROID__)
void* init_accessibility_on_session_bus_for_test(View& root,
                                                 std::string* out_bus_name);
#endif
 
} // namespace pulp::view