From: Jan Grulich <jgrulich@redhat.com>
Date: Fri, 2 Feb 2024 11:47:00 +0000
Subject: Bug 1876896 - WebRTC backport: Allow VideoCaptureModulePipeWire to be
 shared with more consumers r=pehrsons,webrtc-reviewers

This is a simple backport of an WebRTC upstream change.

Upstream commit: 958c9ac546f33716d097b5092515dcac705151d3

Differential Revision: https://phabricator.services.mozilla.com/D200142
Mercurial Revision: https://hg.mozilla.org/mozilla-central/rev/2ba2ef65280b2e6f246fed24d6986718981744f5
---
 .../video_capture/linux/video_capture_pipewire.cc | 15 ++++++++++++++-
 .../video_capture/linux/video_capture_pipewire.h  |  1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/modules/video_capture/linux/video_capture_pipewire.cc b/modules/video_capture/linux/video_capture_pipewire.cc
index 9d47e3ddbf..fb813e331f 100644
--- a/modules/video_capture/linux/video_capture_pipewire.cc
+++ b/modules/video_capture/linux/video_capture_pipewire.cc
@@ -48,7 +48,10 @@ VideoType VideoCaptureModulePipeWire::PipeWireRawFormatToVideoType(
 
 VideoCaptureModulePipeWire::VideoCaptureModulePipeWire(
     VideoCaptureOptions* options)
-    : VideoCaptureImpl(), session_(options->pipewire_session()) {}
+    : VideoCaptureImpl(),
+      session_(options->pipewire_session()),
+      initialized_(false),
+      started_(false) {}
 
 VideoCaptureModulePipeWire::~VideoCaptureModulePipeWire() {
   RTC_DCHECK_RUN_ON(&api_checker_);
@@ -121,6 +124,14 @@ int32_t VideoCaptureModulePipeWire::StartCapture(
   RTC_CHECK_RUNS_SERIALIZED(&capture_checker_);
   RTC_DCHECK_RUN_ON(&api_checker_);
 
+  if (initialized_) {
+    if (capability == _requestedCapability) {
+      return 0;
+    } else {
+      StopCapture();
+    }
+  }
+
   uint8_t buffer[1024] = {};
 
   RTC_LOG(LS_VERBOSE) << "Creating new PipeWire stream for node " << node_id_;
@@ -171,6 +182,8 @@ int32_t VideoCaptureModulePipeWire::StartCapture(
   }
 
   _requestedCapability = capability;
+  initialized_ = true;
+
   return 0;
 }
 
diff --git a/modules/video_capture/linux/video_capture_pipewire.h b/modules/video_capture/linux/video_capture_pipewire.h
index 620ee520ca..5d6794ed65 100644
--- a/modules/video_capture/linux/video_capture_pipewire.h
+++ b/modules/video_capture/linux/video_capture_pipewire.h
@@ -50,6 +50,7 @@ class VideoCaptureModulePipeWire : public VideoCaptureImpl {
   int node_id_ RTC_GUARDED_BY(capture_checker_);
   VideoCaptureCapability configured_capability_
       RTC_GUARDED_BY(pipewire_checker_);
+  bool initialized_ RTC_GUARDED_BY(capture_checker_);
   bool started_ RTC_GUARDED_BY(api_lock_);
 
   struct pw_stream* stream_ RTC_GUARDED_BY(pipewire_checker_) = nullptr;