bluetooth: Support HFGW in module-bluetooth-policy

Add support for hfgw card profile in module-bluetooth-policy, just like
a2dp_source is handled.

In this case also the sink needs to be connected using module-loopback.

src/modules/bluetooth/module-bluetooth-policy.c

@@ -40,16 +40,20 @@ PA_MODULE_DESCRIPTION("When a bluetooth sink or source is added, load module-loo
 PA_MODULE_VERSION(PACKAGE_VERSION);
 PA_MODULE_LOAD_ONCE(TRUE);
 PA_MODULE_USAGE(
-        "a2dp_source=<Handle a2dp_source card profile (sink role)?>");
+        "a2dp_source=<Handle a2dp_source card profile (sink role)?> "
+        "hfgw=<Handle hfgw card profile (headset role)?>");
 
 static const char* const valid_modargs[] = {
     "a2dp_source",
+    "hfgw",
     NULL
 };
 
 struct userdata {
     bool enable_a2dp_source;
+    bool enable_hfgw;
     pa_hook_slot *source_put_slot;
+    pa_hook_slot *sink_put_slot;
 };
 
 /* When a source is created, loopback it to default sink */
@@ -76,6 +80,8 @@ static pa_hook_result_t source_put_hook_callback(pa_core *c, pa_source *source,
 
     if (u->enable_a2dp_source && pa_streq(s, "a2dp_source")) /* A2DP profile (we're doing sink role) */
         role = "music";
+    else if (u->enable_hfgw && pa_streq(s, "hfgw")) /* HFP profile (we're doing headset role) */
+        role = "phone";
     else {
         pa_log_debug("Profile %s cannot be selected for loopback", s);
         return PA_HOOK_OK;
@@ -89,6 +95,43 @@ static pa_hook_result_t source_put_hook_callback(pa_core *c, pa_source *source,
     return PA_HOOK_OK;
 }
 
+/* When a sink is created, loopback it to default source */
+static pa_hook_result_t sink_put_hook_callback(pa_core *c, pa_sink *sink, void *userdata) {
+    struct userdata *u = userdata;
+    const char *s;
+    const char *role;
+    char *args;
+
+    pa_assert(c);
+    pa_assert(sink);
+
+    /* Only consider bluetooth sinks and sources */
+    s = pa_proplist_gets(sink->proplist, PA_PROP_DEVICE_BUS);
+    if (!s)
+        return PA_HOOK_OK;
+
+    if (!pa_streq(s, "bluetooth"))
+        return PA_HOOK_OK;
+
+    s = pa_proplist_gets(sink->proplist, "bluetooth.protocol");
+    if (!s)
+        return PA_HOOK_OK;
+
+    if (u->enable_hfgw && pa_streq(s, "hfgw")) /* HFP profile (we're doing headset role) */
+        role = "phone";
+    else {
+        pa_log_debug("Profile %s cannot be selected for loopback", s);
+        return PA_HOOK_OK;
+    }
+
+    /* Load module-loopback */
+    args = pa_sprintf_malloc("sink=\"%s\" sink_dont_move=\"true\" source_output_properties=\"media.role=%s\"", sink->name, role);
+    (void) pa_module_load(c, "module-loopback", args);
+    pa_xfree(args);
+
+    return PA_HOOK_OK;
+}
+
 int pa__init(pa_module *m) {
     pa_modargs *ma;
     struct userdata *u;
@@ -108,8 +151,16 @@ int pa__init(pa_module *m) {
         goto fail;
     }
 
+    u->enable_hfgw = TRUE;
+    if (pa_modargs_get_value_boolean(ma, "hfgw", &u->enable_hfgw) < 0) {
+        pa_log("Failed to parse hfgw argument.");
+        goto fail;
+    }
+
     u->source_put_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SOURCE_PUT], PA_HOOK_NORMAL, (pa_hook_cb_t) source_put_hook_callback, u);
 
+    u->sink_put_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_PUT], PA_HOOK_NORMAL, (pa_hook_cb_t) sink_put_hook_callback, u);
+
     pa_modargs_free(ma);
     return 0;
 
@@ -129,5 +180,8 @@ void pa__done(pa_module *m) {
     if (u->source_put_slot)
         pa_hook_slot_free(u->source_put_slot);
 
+    if (u->sink_put_slot)
+        pa_hook_slot_free(u->sink_put_slot);
+
     pa_xfree(u);
 }