card: add preferred_{input, output}_port

I will modify module-switch-on-port-available so that it will keep
track of which input and output port the user prefers on the card,
based on the user's profile and port switches. The preference needs
to be saved on disk, for which I will use module-card-restore.

To facilitate communication between the two modules, this patch adds
preferred_input_port and preferred_output_port fields to pa_card, and
a hook for monitoring the variable changes. It would be nice if the
two modules would communicate directly with each other, but
implementing that would be somewhat complicated, so I chose this time
for adding the functionality to the core. In theory some other routing
module might want to manage the new variables instead of
module-switch-on-port-available, but admittedly that's not very likely
to happen...

3 files changed, 59 insertions, 0 deletions

diff --git a/src/pulsecore/card.c b/src/pulsecore/card.c
index b6cbbf7cf..0eaccff10 100644
--- a/src/pulsecore/card.c
+++ b/src/pulsecore/card.c
@@ -103,6 +103,15 @@ void pa_card_new_data_set_profile(pa_card_new_data *data, const char *profile) {
     data->active_profile = pa_xstrdup(profile);
 }
 
+void pa_card_new_data_set_preferred_port(pa_card_new_data *data, pa_direction_t direction, pa_device_port *port) {
+    pa_assert(data);
+
+    if (direction == PA_DIRECTION_INPUT)
+        data->preferred_input_port = port;
+    else
+        data->preferred_output_port = port;
+}
+
 void pa_card_new_data_done(pa_card_new_data *data) {
 
     pa_assert(data);
@@ -169,6 +178,9 @@ pa_card *pa_card_new(pa_core *core, pa_card_new_data *data) {
     PA_HASHMAP_FOREACH(port, c->ports, state)
         port->card = c;
 
+    c->preferred_input_port = data->preferred_input_port;
+    c->preferred_output_port = data->preferred_output_port;
+
     if (data->active_profile)
         if ((c->active_profile = pa_hashmap_get(c->profiles, data->active_profile)))
             c->save_profile = data->save_profile;
@@ -309,6 +321,40 @@ int pa_card_set_profile(pa_card *c, pa_card_profile *profile, bool save) {
     return 0;
 }
 
+void pa_card_set_preferred_port(pa_card *c, pa_direction_t direction, pa_device_port *port) {
+    pa_device_port *old_port;
+    const char *old_port_str;
+    const char *new_port_str;
+    pa_card_preferred_port_changed_hook_data data;
+
+    pa_assert(c);
+
+    if (direction == PA_DIRECTION_INPUT) {
+        old_port = c->preferred_input_port;
+        old_port_str = c->preferred_input_port ? c->preferred_input_port->name : "(unset)";
+    } else {
+        old_port = c->preferred_output_port;
+        old_port_str = c->preferred_output_port ? c->preferred_output_port->name : "(unset)";
+    }
+
+    if (port == old_port)
+        return;
+
+    new_port_str = port ? port->name : "(unset)";
+
+    if (direction == PA_DIRECTION_INPUT) {
+        c->preferred_input_port = port;
+        pa_log_debug("%s: preferred_input_port: %s -> %s", c->name, old_port_str, new_port_str);
+    } else {
+        c->preferred_output_port = port;
+        pa_log_debug("%s: preferred_output_port: %s -> %s", c->name, old_port_str, new_port_str);
+    }
+
+    data.card = c;
+    data.direction = direction;
+    pa_hook_fire(&c->core->hooks[PA_CORE_HOOK_CARD_PREFERRED_PORT_CHANGED], &data);
+}
+
 int pa_card_suspend(pa_card *c, bool suspend, pa_suspend_cause_t cause) {
     pa_sink *sink;
     pa_source *source;
diff --git a/src/pulsecore/card.h b/src/pulsecore/card.h
index 30bfc0ecd..79966f35b 100644
--- a/src/pulsecore/card.h
+++ b/src/pulsecore/card.h
@@ -79,6 +79,8 @@ struct pa_card {
     pa_card_profile *active_profile;
 
     pa_hashmap *ports;
+    pa_device_port *preferred_input_port;
+    pa_device_port *preferred_output_port;
 
     bool save_profile:1;
 
@@ -98,12 +100,19 @@ typedef struct pa_card_new_data {
     char *active_profile;
 
     pa_hashmap *ports;
+    pa_device_port *preferred_input_port;
+    pa_device_port *preferred_output_port;
 
     bool namereg_fail:1;
 
     bool save_profile:1;
 } pa_card_new_data;
 
+typedef struct {
+    pa_card *card;
+    pa_direction_t direction;
+} pa_card_preferred_port_changed_hook_data;
+
 pa_card_profile *pa_card_profile_new(const char *name, const char *description, size_t extra);
 void pa_card_profile_free(pa_card_profile *c);
 
@@ -113,6 +122,7 @@ void pa_card_profile_set_available(pa_card_profile *c, pa_available_t available)
 pa_card_new_data *pa_card_new_data_init(pa_card_new_data *data);
 void pa_card_new_data_set_name(pa_card_new_data *data, const char *name);
 void pa_card_new_data_set_profile(pa_card_new_data *data, const char *profile);
+void pa_card_new_data_set_preferred_port(pa_card_new_data *data, pa_direction_t direction, pa_device_port *port);
 void pa_card_new_data_done(pa_card_new_data *data);
 
 pa_card *pa_card_new(pa_core *c, pa_card_new_data *data);
@@ -122,6 +132,8 @@ void pa_card_add_profile(pa_card *c, pa_card_profile *profile);
 
 int pa_card_set_profile(pa_card *c, pa_card_profile *profile, bool save);
 
+void pa_card_set_preferred_port(pa_card *c, pa_direction_t direction, pa_device_port *port);
+
 int pa_card_suspend(pa_card *c, bool suspend, pa_suspend_cause_t cause);
 
 #endif
diff --git a/src/pulsecore/core.h b/src/pulsecore/core.h
index 1a3c4902e..69ab4d0ca 100644
--- a/src/pulsecore/core.h
+++ b/src/pulsecore/core.h
@@ -120,6 +120,7 @@ typedef enum pa_core_hook {
     PA_CORE_HOOK_CARD_NEW,
     PA_CORE_HOOK_CARD_PUT,
     PA_CORE_HOOK_CARD_UNLINK,
+    PA_CORE_HOOK_CARD_PREFERRED_PORT_CHANGED,
     PA_CORE_HOOK_CARD_PROFILE_CHANGED,
     PA_CORE_HOOK_CARD_PROFILE_ADDED,
     PA_CORE_HOOK_CARD_PROFILE_AVAILABLE_CHANGED,