From b3931999f48234044c1db2085ae7ae10eaf55b5a Mon Sep 17 00:00:00 2001
From: Julian Orth <ju.orth@gmail.com>
Date: Mon, 20 May 2024 14:07:41 +0200
Subject: [PATCH] pipewire: updates buffer metadata in correct order

---
 src/pipewire/pw_ifs/pw_client_node.rs |  8 +--
 src/portal/ptl_screencast.rs          | 85 +++++++++++++--------------
 2 files changed, 46 insertions(+), 47 deletions(-)

diff --git a/src/pipewire/pw_ifs/pw_client_node.rs b/src/pipewire/pw_ifs/pw_client_node.rs
index ac139ac1..33b3f1e5 100644
--- a/src/pipewire/pw_ifs/pw_client_node.rs
+++ b/src/pipewire/pw_ifs/pw_client_node.rs
@@ -120,7 +120,7 @@ pub struct PwClientNodePort {
 
     pub buffer_config: Cell<Option<PwClientNodeBufferConfig>>,
 
-    pub io_buffers: CopyHashMap<u32, Rc<PwMemTyped<spa_io_buffers>>>,
+    pub io_buffers: CloneCell<Option<Rc<PwMemTyped<spa_io_buffers>>>>,
 
     pub serial: Cell<bool>,
 }
@@ -705,12 +705,12 @@ impl PwClientNode {
         let size = p2.read_uint()?;
         let port = self.get_port(direction, port_id)?;
         match id {
-            SPA_IO_Buffers => {
+            SPA_IO_Buffers if mix_id == 0 => {
                 if mem_id == !0 {
-                    port.io_buffers.remove(&mix_id);
+                    port.io_buffers.take();
                 } else {
                     port.io_buffers
-                        .set(mix_id, self.con.mem.map(mem_id, offset, size)?.typed());
+                        .set(Some(self.con.mem.map(mem_id, offset, size)?.typed()));
                 }
             }
             _ => {}
diff --git a/src/portal/ptl_screencast.rs b/src/portal/ptl_screencast.rs
index fafc706b..4b954000 100644
--- a/src/portal/ptl_screencast.rs
+++ b/src/portal/ptl_screencast.rs
@@ -405,54 +405,53 @@ impl UsrJayScreencastOwner for StartedScreencast {
 
     fn ready(&self, ev: &Ready) {
         let idx = ev.idx as usize;
-        if !self.buffers_valid.get() {
+        let buffers = &*self.buffers.borrow();
+        let pbuffers = self.port.buffers.borrow();
+        let buffer = &buffers[idx];
+        let discard_buffer = || {
             self.jay_screencast.release_buffer(idx);
+        };
+        if !self.buffers_valid.get() {
+            discard_buffer();
             return;
         }
-        unsafe {
-            let mut used = false;
-            if let Some(io) = self.port.io_buffers.lock().values().next() {
-                let io = io.write();
-                let status = io.status.load(Acquire);
-                if status != SPA_STATUS_HAVE_DATA.0 {
-                    used = true;
-                    let buffer_id = io.buffer_id.load(Relaxed);
-                    if buffer_id != ev.idx {
-                        if (buffer_id as usize) < self.buffers.borrow_mut().len() {
-                            self.jay_screencast.release_buffer(buffer_id as usize);
-                        }
-                    }
-                    io.buffer_id.store(ev.idx, Relaxed);
-                    io.status.store(SPA_STATUS_HAVE_DATA.0, Release);
-                }
-            }
-            if !used {
-                self.jay_screencast.release_buffer(idx);
-            }
-            {
-                let pbuffers = self.port.buffers.borrow_mut();
-                let buffers = self.buffers.borrow_mut();
-                if let Some(pbuffer) = pbuffers.get(idx) {
-                    let buffer = &buffers[idx];
-                    for (chunk, plane) in pbuffer.chunks.iter().zip(buffer.planes.iter()) {
-                        let chunk = chunk.write();
-                        chunk.flags = SpaChunkFlags::none();
-                        chunk.offset = plane.offset;
-                        chunk.stride = plane.stride;
-                        chunk.size = plane.stride * buffer.height as u32;
-                    }
-                    if let Some(crop) = &pbuffer.meta_video_crop {
-                        crop.write().region = spa_region {
-                            position: spa_point { x: 0, y: 0 },
-                            size: spa_rectangle {
-                                width: buffer.width as _,
-                                height: buffer.height as _,
-                            },
-                        };
-                    }
-                }
+        let Some(io) = self.port.io_buffers.get() else {
+            discard_buffer();
+            return;
+        };
+        let Some(pbuffer) = pbuffers.get(idx) else {
+            discard_buffer();
+            return;
+        };
+        let io = unsafe { io.read() };
+        if io.status.load(Acquire) == SPA_STATUS_HAVE_DATA.0 {
+            discard_buffer();
+            return;
+        }
+        for (chunk, plane) in pbuffer.chunks.iter().zip(buffer.planes.iter()) {
+            let chunk = unsafe { chunk.write() };
+            chunk.flags = SpaChunkFlags::none();
+            chunk.offset = plane.offset;
+            chunk.stride = plane.stride;
+            chunk.size = plane.stride * buffer.height as u32;
+        }
+        if let Some(crop) = &pbuffer.meta_video_crop {
+            unsafe { crop.write() }.region = spa_region {
+                position: spa_point { x: 0, y: 0 },
+                size: spa_rectangle {
+                    width: buffer.width as _,
+                    height: buffer.height as _,
+                },
+            };
+        }
+        let buffer_id = io.buffer_id.load(Relaxed) as usize;
+        if buffer_id != idx {
+            if buffer_id < buffers.len() {
+                self.jay_screencast.release_buffer(buffer_id);
             }
         }
+        io.buffer_id.store(ev.idx, Relaxed);
+        io.status.store(SPA_STATUS_HAVE_DATA.0, Release);
         if let Some(wfd) = self.port.node.transport_out.get() {
             let _ = uapi::eventfd_write(wfd.raw(), 1);
         }