Add field_if_some setter for builder ClockTime fields

Optional `ClockTime` fields already implemented their setters in such a way
that they could accept either `Option<ClockTime>` or `ClockTime`. This commit
adds `field_if_some()` setter variants for builder `ClockTime` builder fields
for consistency with other builder fields.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1424>

gstreamer-video/src/video_event.rs

@@ -138,6 +138,14 @@ impl<'a> DownstreamForceKeyUnitEventBuilder<'a> {
         }
     }
 
+    pub fn timestamp_if_some(self, timestamp: Option<gst::ClockTime>) -> Self {
+        if let Some(timestamp) = timestamp {
+            self.timestamp(timestamp)
+        } else {
+            self
+        }
+    }
+
     pub fn stream_time(self, stream_time: impl Into<Option<gst::ClockTime>>) -> Self {
         Self {
             stream_time: stream_time.into(),
@@ -145,6 +153,14 @@ impl<'a> DownstreamForceKeyUnitEventBuilder<'a> {
         }
     }
 
+    pub fn stream_time_if_some(self, stream_time: Option<gst::ClockTime>) -> Self {
+        if let Some(stream_time) = stream_time {
+            self.stream_time(stream_time)
+        } else {
+            self
+        }
+    }
+
     pub fn running_time(self, running_time: impl Into<Option<gst::ClockTime>>) -> Self {
         Self {
             running_time: running_time.into(),
@@ -152,6 +168,14 @@ impl<'a> DownstreamForceKeyUnitEventBuilder<'a> {
         }
     }
 
+    pub fn running_time_if_some(self, running_time: Option<gst::ClockTime>) -> Self {
+        if let Some(running_time) = running_time {
+            self.running_time(running_time)
+        } else {
+            self
+        }
+    }
+
     pub fn all_headers(self, all_headers: bool) -> Self {
         Self {
             all_headers,
@@ -268,6 +292,14 @@ impl<'a> UpstreamForceKeyUnitEventBuilder<'a> {
         }
     }
 
+    pub fn running_time_if_some(self, running_time: Option<gst::ClockTime>) -> Self {
+        if let Some(running_time) = running_time {
+            self.running_time(running_time)
+        } else {
+            self
+        }
+    }
+
     pub fn all_headers(self, all_headers: bool) -> Self {
         Self {
             all_headers,

gstreamer/src/event.rs

@@ -2634,6 +2634,14 @@ impl<'a> GapBuilder<'a> {
         self
     }
 
+    pub fn duration_if_some(self, duration: Option<ClockTime>) -> Self {
+        if let Some(duration) = duration {
+            self.duration(duration)
+        } else {
+            self
+        }
+    }
+
     event_builder_generic_impl!(|s: &Self| {
         #[allow(clippy::let_and_return)]
         let ev = ffi::gst_event_new_gap(s.timestamp.into_glib(), s.duration.into_glib());
@@ -2700,6 +2708,14 @@ impl<'a> QosBuilder<'a> {
         self
     }
 
+    pub fn timestamp_if_some(self, timestamp: Option<ClockTime>) -> Self {
+        if let Some(timestamp) = timestamp {
+            self.timestamp(timestamp)
+        } else {
+            self
+        }
+    }
+
     event_builder_generic_impl!(|s: &Self| ffi::gst_event_new_qos(
         s.type_.into_glib(),
         s.proportion,

gstreamer/src/message.rs

@@ -3276,6 +3276,14 @@ impl<'a> AsyncDoneBuilder<'a> {
         self
     }
 
+    pub fn running_time_if_some(self, running_time: Option<crate::ClockTime>) -> Self {
+        if let Some(running_time) = running_time {
+            self.running_time(running_time)
+        } else {
+            self
+        }
+    }
+
     message_builder_generic_impl!(|s: &mut Self, src| ffi::gst_message_new_async_done(
         src,
         s.running_time.into_glib()
@@ -3375,21 +3383,53 @@ impl<'a> QosBuilder<'a> {
         self
     }
 
+    pub fn running_time_if_some(self, running_time: Option<crate::ClockTime>) -> Self {
+        if let Some(running_time) = running_time {
+            self.running_time(running_time)
+        } else {
+            self
+        }
+    }
+
     pub fn stream_time(mut self, stream_time: impl Into<Option<crate::ClockTime>>) -> Self {
         self.stream_time = stream_time.into();
         self
     }
 
+    pub fn stream_time_if_some(self, stream_time: Option<crate::ClockTime>) -> Self {
+        if let Some(stream_time) = stream_time {
+            self.stream_time(stream_time)
+        } else {
+            self
+        }
+    }
+
     pub fn timestamp(mut self, timestamp: impl Into<Option<crate::ClockTime>>) -> Self {
         self.timestamp = timestamp.into();
         self
     }
 
+    pub fn timestamp_if_some(self, timestamp: Option<crate::ClockTime>) -> Self {
+        if let Some(timestamp) = timestamp {
+            self.timestamp(timestamp)
+        } else {
+            self
+        }
+    }
+
     pub fn duration(mut self, duration: impl Into<Option<crate::ClockTime>>) -> Self {
         self.duration = duration.into();
         self
     }
 
+    pub fn duration_if_some(self, duration: Option<crate::ClockTime>) -> Self {
+        if let Some(duration) = duration {
+            self.duration(duration)
+        } else {
+            self
+        }
+    }
+
     pub fn values(self, jitter: i64, proportion: f64, quality: i32) -> Self {
         Self {
             values: Some((jitter, proportion, quality)),