From 2fd02c7e68fa14de9796bd14e4c61e96673a9412 Mon Sep 17 00:00:00 2001
From: Jasper Hugo <jasper@avstack.io>
Date: Tue, 17 Aug 2021 08:55:17 +0700
Subject: [PATCH] provide a ctx argument for the C API callbacks

---
 lib-gst-meet-c/include/gstmeet.h |  3 ++-
 lib-gst-meet-c/src/lib.rs        | 46 ++++++++++++++++++--------------
 lib-gst-meet/src/conference.rs   | 29 +++++---------------
 shell.nix                        |  3 +++
 4 files changed, 38 insertions(+), 43 deletions(-)

diff --git a/lib-gst-meet-c/include/gstmeet.h b/lib-gst-meet-c/include/gstmeet.h
index 8b5654a..bdfc3e8 100644
--- a/lib-gst-meet-c/include/gstmeet.h
+++ b/lib-gst-meet-c/include/gstmeet.h
@@ -67,6 +67,7 @@ GstElement *gstmeet_conference_video_sink_element(struct Context *context,
 
 void gstmeet_conference_on_participant(struct Context *context,
                                        JitsiConference *conference,
-                                       GstBin *(*f)(struct Participant));
+                                       GstBin *(*f)(struct Participant, void *),
+                                       void *callback_context);
 
 #endif /* gstmeet_h */
diff --git a/lib-gst-meet-c/src/lib.rs b/lib-gst-meet-c/src/lib.rs
index 38f35f9..ac3ca9f 100644
--- a/lib-gst-meet-c/src/lib.rs
+++ b/lib-gst-meet-c/src/lib.rs
@@ -1,7 +1,8 @@
 use std::{
-  ffi::{CStr, CString},
+  ffi::{CStr, CString, c_void},
   os::raw::c_char,
   ptr,
+  sync::{Arc, atomic::{AtomicPtr, Ordering}},
 };
 
 use anyhow::Result;
@@ -186,26 +187,31 @@ pub unsafe extern "C" fn gstmeet_conference_video_sink_element(context: *mut Con
 pub unsafe extern "C" fn gstmeet_conference_on_participant(
   context: *mut Context,
   conference: *mut JitsiConference,
-  f: unsafe extern "C" fn(Participant) -> *mut gstreamer::ffi::GstBin,
+  f: unsafe extern "C" fn(Participant, *mut c_void) -> *mut gstreamer::ffi::GstBin,
+  ctx: *mut c_void,
 ) {
+  let ctx = Arc::new(AtomicPtr::new(ctx));
   (*context)
     .runtime
-    .block_on((*conference).on_participant(move |participant| Box::pin(async move {
-      let participant = Participant {
-        jid: CString::new(participant.jid.to_string())?.into_raw() as *const _,
-        muc_jid: CString::new(participant.muc_jid.to_string())?.into_raw() as *const _,
-        nick: participant
-          .nick
-          .map(|nick| Ok::<_, anyhow::Error>(CString::new(nick)?.into_raw() as *const _))
-          .transpose()?
-          .unwrap_or_else(ptr::null),
-      };
-      let maybe_bin = f(participant);
-      if maybe_bin.is_null() {
-        Ok(None)
-      }
-      else {
-        Ok(Some(from_glib_full(maybe_bin)))
-      }
-    })));
+    .block_on((*conference).on_participant(move |participant| {
+      let ctx = ctx.clone();
+      Box::pin(async move {
+        let participant = Participant {
+          jid: CString::new(participant.jid.to_string())?.into_raw() as *const _,
+          muc_jid: CString::new(participant.muc_jid.to_string())?.into_raw() as *const _,
+          nick: participant
+            .nick
+            .map(|nick| Ok::<_, anyhow::Error>(CString::new(nick)?.into_raw() as *const _))
+            .transpose()?
+            .unwrap_or_else(ptr::null),
+        };
+        let maybe_bin = f(participant, ctx.load(Ordering::Relaxed));
+        if maybe_bin.is_null() {
+          Ok(None)
+        }
+        else {
+          Ok(Some(from_glib_full(maybe_bin)))
+        }
+      })
+    }));
 }
\ No newline at end of file
diff --git a/lib-gst-meet/src/conference.rs b/lib-gst-meet/src/conference.rs
index 46772b8..450b28f 100644
--- a/lib-gst-meet/src/conference.rs
+++ b/lib-gst-meet/src/conference.rs
@@ -94,17 +94,14 @@ pub struct Participant {
   bin: Option<gstreamer::Bin>,
 }
 
+type BoxedBinResultFuture = Pin<Box<dyn Future<Output = Result<Option<gstreamer::Bin>>> + Send>>;
+type BoxedResultFuture = Pin<Box<dyn Future<Output = Result<()>> + Send>>;
+
 pub(crate) struct JitsiConferenceInner {
   pub(crate) jingle_session: Option<JingleSession>,
   participants: HashMap<String, Participant>,
-  on_participant: Option<
-    Arc<
-      dyn (Fn(Participant) -> Pin<Box<dyn Future<Output = Result<Option<gstreamer::Bin>>> + Send>>)
-        + Send
-        + Sync,
-    >,
-  >,
-  on_participant_left: Option<Arc<dyn (Fn(Participant) -> Pin<Box<dyn Future<Output = Result<()>> + Send>>) + Send + Sync>>,
+  on_participant: Option<Arc<dyn (Fn(Participant) -> BoxedBinResultFuture) + Send + Sync>>,
+  on_participant_left: Option<Arc<dyn (Fn(Participant) -> BoxedResultFuture) + Send + Sync>>,
   state: JitsiConferenceState,
   connected_tx: Option<oneshot::Sender<()>>,
   connected_rx: Option<oneshot::Receiver<()>>,
@@ -273,13 +270,7 @@ impl JitsiConference {
   }
 
   #[tracing::instrument(level = "trace", skip(f))]
-  pub async fn on_participant(
-    &self,
-    f: impl (Fn(Participant) -> Pin<Box<dyn Future<Output = Result<Option<gstreamer::Bin>>> + Send>>)
-    + Send
-    + Sync
-    + 'static,
-  ) {
+  pub async fn on_participant(&self, f: impl (Fn(Participant) -> BoxedBinResultFuture) + Send + Sync + 'static) {
     let f = Arc::new(f);
     let f2 = f.clone();
     let existing_participants: Vec<_> = {
@@ -320,13 +311,7 @@ impl JitsiConference {
   }
 
   #[tracing::instrument(level = "trace", skip(f))]
-  pub async fn on_participant_left(
-    &self,
-    f: impl (Fn(Participant) -> Pin<Box<dyn Future<Output = Result<()>> + Send>>)
-    + Send
-    + Sync
-    + 'static,
-  ) {
+  pub async fn on_participant_left(&self, f: impl (Fn(Participant) -> BoxedResultFuture) + Send + Sync + 'static) {
     self.inner.lock().await.on_participant_left = Some(Arc::new(f));
   }
 }
diff --git a/shell.nix b/shell.nix
index 11040dd..d08a169 100644
--- a/shell.nix
+++ b/shell.nix
@@ -4,6 +4,7 @@ mkShell {
   buildInputs = [
     pkg-config
     glib
+    glib-networking
     gst_all_1.gstreamer
     gst_all_1.gst-plugins-base
     gst_all_1.gst-plugins-good
@@ -13,4 +14,6 @@ mkShell {
     darwin.apple_sdk.frameworks.AppKit
     darwin.apple_sdk.frameworks.Security
   ] else []);
+
+  GIO_EXTRA_MODULES = ["${pkgs.glib-networking.out}/lib/gio/modules"];
 }