[PATCH weston v3 2/2] compositor: allow to control the vt switching

[Giulio Camuffo]

A compositor may want to control the vt switching, for example to
ensure to have a lock screen before it. To enable that add a vfunc
that will be called when CTRL+ALT+FN is pressed. The default behavior
is to do the switching, but the user can change it by using the new
weston_compositor_set_vt_switcher() function, so that it can delay the
switching to later, by calling weston_compositor_activate_vt().

Signed-off-by: Giulio Camuffo <giuliocamuffo at gmail.com>
---

v3: removed leftover include, fix wrong name in documentation

 Makefile.am               |  2 +-
 libweston/compositor.c    | 18 ++++++++++++++++++
 libweston/compositor.h    | 39 +++++++++++++++++++++++++++++++++++++++
 libweston/launcher-impl.h |  1 +
 libweston/launcher-util.c |  6 +++++-
 5 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 2219e3d..1a13b85 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -74,7 +74,7 @@ libweston_ at LIBWESTON_MAJOR@_la_CPPFLAGS = $(AM_CPPFLAGS) -DIN_WESTON
 libweston_ at LIBWESTON_MAJOR@_la_CFLAGS = $(AM_CFLAGS) $(COMPOSITOR_CFLAGS) $(LIBUNWIND_CFLAGS)
 libweston_ at LIBWESTON_MAJOR@_la_LIBADD = $(COMPOSITOR_LIBS) $(LIBUNWIND_LIBS) \
 	$(DLOPEN_LIBS) -lm $(CLOCK_GETTIME_LIBS) \
-	$(LIBINPUT_BACKEND_LIBS) libshared.la
+	$(LIBINPUT_BACKEND_LIBS) libshared.la libsession-helper.la
 libweston_ at LIBWESTON_MAJOR@_la_LDFLAGS = -version-info $(LT_VERSION_INFO)
 
 libweston_ at LIBWESTON_MAJOR@_la_SOURCES =			\
diff --git a/libweston/compositor.c b/libweston/compositor.c
index 6457858..6e44c72 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -55,6 +55,8 @@
 
 #include "compositor.h"
 #include "viewporter-server-protocol.h"
+#include "launcher-impl.h"
+#include "launcher-util.h"
 #include "presentation-time-server-protocol.h"
 #include "shared/helpers.h"
 #include "shared/os-compatibility.h"
@@ -4922,6 +4924,22 @@ compositor_bind(struct wl_client *client,
 }
 
 WL_EXPORT int
+weston_compositor_activate_vt(struct weston_compositor *compositor, int vt)
+{
+	if (compositor->launcher)
+		return weston_launcher_activate_vt(compositor->launcher, vt);
+	return -1;
+}
+
+WL_EXPORT void
+weston_compositor_set_vt_switcher(struct weston_compositor *compositor,
+				  weston_compositor_vt_switcher_func_t switcher)
+{
+	if (compositor->launcher)
+		compositor->launcher->vt_switcher = switcher;
+}
+
+WL_EXPORT int
 weston_environment_get_fd(const char *env)
 {
 	char *e;
diff --git a/libweston/compositor.h b/libweston/compositor.h
index ce3d9ab..114d618 100644
--- a/libweston/compositor.h
+++ b/libweston/compositor.h
@@ -1447,6 +1447,45 @@ void
 weston_compositor_set_default_pointer_grab(struct weston_compositor *compositor,
 			const struct weston_pointer_grab_interface *interface);
 
+/**
+ * Request a vt switch for the compositor.
+ *
+ * This will only work if the compositor is running as the owner of
+ * the session.
+ *
+ * \param compositor The compositor instance.
+ * \param vt The vt to switch to.
+ *
+ * Returns 0 on success, -1 otherwise.
+ *
+ * \sa weston_compositor_set_vt_switcher
+ */
+int
+weston_compositor_activate_vt(struct weston_compositor *compositor, int vt);
+
+typedef void (*weston_compositor_vt_switcher_func_t)(
+		struct weston_compositor *compositor, int vt);
+/**
+ * Set the vt switcher for the compositor.
+ *
+ * If the compositor is the owner of the session, the CTRL+ALT+FN key
+ * combinations will trigger a vt switch. The default behavior is to do
+ * the switching immediately, but some compositors may want to make sure to
+ * e.g. draw a lock screen before doing the switch.
+ * This function allows to register a custom vt switcher so that the actual
+ * vt switch can be controlled by calling \a weston_compositor_activate_vt.
+ *
+ * \param compositor The compositor instance.
+ * \param switcher The vt switcher function, which will be called when a
+ *                 CTRL+ALT+FN key combination is pressed, carrying the
+ *                 requested vt.
+ *
+ * \sa weston_compositor_activate_vt
+ */
+void
+weston_compositor_set_vt_switcher(struct weston_compositor *compositor,
+				  weston_compositor_vt_switcher_func_t switcher);
+
 int
 weston_environment_get_fd(const char *env);
 
diff --git a/libweston/launcher-impl.h b/libweston/launcher-impl.h
index 8d09025..8ba1673 100644
--- a/libweston/launcher-impl.h
+++ b/libweston/launcher-impl.h
@@ -40,6 +40,7 @@ struct launcher_interface {
 
 struct weston_launcher {
 	struct launcher_interface *iface;
+	weston_compositor_vt_switcher_func_t vt_switcher;
 };
 
 extern struct launcher_interface launcher_logind_iface;
diff --git a/libweston/launcher-util.c b/libweston/launcher-util.c
index 2b828be..5845cf3 100644
--- a/libweston/launcher-util.c
+++ b/libweston/launcher-util.c
@@ -100,11 +100,15 @@ switch_vt_binding(struct weston_keyboard *keyboard,
 	struct weston_compositor *compositor = data;
 	struct weston_launcher *launcher = compositor->launcher;
 	int vt = key - KEY_F1 + 1;
+	weston_compositor_vt_switcher_func_t switcher = launcher->vt_switcher;
 
 	if (vt == launcher->iface->get_vt(launcher))
 		return;
 
-	weston_launcher_activate_vt(launcher, vt);
+	if (switcher)
+		launcher->vt_switcher(compositor, vt);
+	else
+		weston_launcher_activate_vt(launcher, vt);
 }
 
 WL_EXPORT void
-- 
2.10.2