gstreamer: Change Sample constructor to the builder pattern

Simplifies construction of Samples considerably.

gstreamer-video/src/functions.rs

@@ -137,12 +137,7 @@ mod tests {
             .unwrap()
             .to_caps()
             .unwrap();
-        let sample = gst::Sample::new(
-            Some(&in_buffer),
-            Some(&in_caps),
-            None::<&gst::Segment>,
-            None,
-        );
+        let sample = gst::Sample::new().buffer(&in_buffer).caps(&in_caps).build();
 
         let out_caps = ::VideoInfo::new(::VideoFormat::Abgr, 320, 240)
             .build()

gstreamer/src/sample.rs

@@ -31,43 +31,89 @@ gst_define_mini_object_wrapper!(Sample, SampleRef, gst_sys::GstSample, [Debug,],
     gst_sys::gst_sample_get_type()
 });
 
-impl Sample {
-    pub fn new<F: FormattedValue>(
-        buffer: Option<&Buffer>,
-        caps: Option<&Caps>,
-        segment: Option<&FormattedSegment<F>>,
+#[derive(Debug, Clone)]
+pub struct SampleBuilder<'a> {
+    buffer: Option<&'a Buffer>,
+    buffer_list: Option<&'a BufferList>,
+    caps: Option<&'a Caps>,
+    segment: Option<&'a Segment>,
     info: Option<Structure>,
-    ) -> Self {
-        assert_initialized_main_thread!();
-        unsafe {
-            let info = info.map(|i| i.into_ptr()).unwrap_or(ptr::null_mut());
+}
 
-            from_glib_full(gst_sys::gst_sample_new(
-                buffer.to_glib_none().0,
-                caps.to_glib_none().0,
-                segment.to_glib_none().0,
+impl<'a> SampleBuilder<'a> {
+    pub fn buffer(self, buffer: &'a Buffer) -> Self {
+        Self {
+            buffer: Some(buffer),
+            buffer_list: None,
+            ..self
+        }
+    }
+
+    pub fn buffer_list(self, buffer_list: &'a BufferList) -> Self {
+        Self {
+            buffer: None,
+            buffer_list: Some(buffer_list),
+            ..self
+        }
+    }
+
+    pub fn caps(self, caps: &'a Caps) -> Self {
+        Self {
+            caps: Some(caps),
+            ..self
+        }
+    }
+
+    pub fn segment<F: FormattedValue>(self, segment: &'a FormattedSegment<F>) -> Self {
+        Self {
+            segment: Some(segment.upcast_ref()),
+            ..self
+        }
+    }
+
+    pub fn info(self, info: Structure) -> Self {
+        Self {
+            info: Some(info),
+            ..self
+        }
+    }
+
+    pub fn build(self) -> Sample {
+        assert_initialized_main_thread!();
+
+        unsafe {
+            let info = self.info.map(|i| i.into_ptr()).unwrap_or(ptr::null_mut());
+
+            let sample: Sample = from_glib_full(gst_sys::gst_sample_new(
+                self.buffer.to_glib_none().0,
+                self.caps.to_glib_none().0,
+                self.segment.to_glib_none().0,
                 mut_override(info),
-            ))
-        }
-    }
+            ));
 
-    pub fn with_buffer_list<F: FormattedValue>(
-        buffer_list: Option<&BufferList>,
-        caps: Option<&Caps>,
-        segment: Option<&FormattedSegment<F>>,
-        info: Option<Structure>,
-    ) -> Self {
-        assert_initialized_main_thread!();
-        let sample = Self::new(None, caps, segment, info);
-        unsafe {
+            if let Some(buffer_list) = self.buffer_list {
                 gst_sys::gst_sample_set_buffer_list(
                     sample.to_glib_none().0,
                     buffer_list.to_glib_none().0,
                 );
             }
+
             sample
         }
     }
+}
+
+impl Sample {
+    pub fn new<'a>() -> SampleBuilder<'a> {
+        SampleBuilder {
+            buffer: None,
+            buffer_list: None,
+            caps: None,
+            segment: None,
+            info: None,
+        }
+    }
+}
 
 impl SampleRef {
     pub fn get_buffer(&self) -> Option<&BufferRef> {
@@ -182,10 +228,8 @@ impl fmt::Debug for SampleRef {
 
 #[cfg(test)]
 mod tests {
-
     #[test]
     fn test_sample_new_with_info() {
-        use GenericFormattedValue;
         use Sample;
         use Structure;
 
@@ -194,7 +238,7 @@ mod tests {
         let info = Structure::builder("sample.info")
             .field("f3", &123i32)
             .build();
-        let sample = Sample::new::<GenericFormattedValue>(None, None, None, Some(info));
+        let sample = Sample::new().info(info).build();
 
         assert!(sample.get_info().is_some());
     }

gstreamer/src/sample_serde.rs

@@ -12,7 +12,6 @@ use serde::ser::{Serialize, SerializeStruct, Serializer};
 use Buffer;
 use BufferList;
 use Caps;
-use GenericFormattedValue;
 use Sample;
 use SampleRef;
 use Segment;
@@ -47,21 +46,29 @@ struct SampleDe {
 
 impl From<SampleDe> for Sample {
     fn from(mut buf_de: SampleDe) -> Self {
-        if buf_de.buffer.is_some() {
-            Sample::new::<GenericFormattedValue>(
-                buf_de.buffer.as_ref(),
-                buf_de.caps.as_ref(),
-                buf_de.segment.as_ref(),
-                buf_de.info.take(),
-            )
-        } else {
-            Sample::with_buffer_list::<GenericFormattedValue>(
-                buf_de.buffer_list.as_ref(),
-                buf_de.caps.as_ref(),
-                buf_de.segment.as_ref(),
-                buf_de.info.take(),
-            )
+        let mut builder = Sample::new();
+
+        if let Some(buffer) = buf_de.buffer.as_ref() {
+            builder = builder.buffer(buffer);
         }
+
+        if let Some(buffer_list) = buf_de.buffer_list.as_ref() {
+            builder = builder.buffer_list(buffer_list);
+        }
+
+        if let Some(caps) = buf_de.caps.as_ref() {
+            builder = builder.caps(caps);
+        }
+
+        if let Some(segment) = buf_de.segment.as_ref() {
+            builder = builder.segment(segment);
+        }
+
+        if let Some(info) = buf_de.info {
+            builder = builder.info(info);
+        }
+
+        builder.build()
     }
 }
 
@@ -124,12 +131,12 @@ mod tests {
                 .field("f3", &123i32)
                 .build();
 
-            Sample::new::<GenericFormattedValue>(
-                Some(&buffer),
-                Some(&caps),
-                Some(&segment),
-                Some(info),
-            )
+            Sample::new()
+                .buffer(&buffer)
+                .caps(&caps)
+                .segment(&segment)
+                .info(info)
+                .build()
         };
 
         let res = ron::ser::to_string_pretty(&sample, pretty_config.clone());
@@ -187,7 +194,7 @@ mod tests {
                 buffer.set_offset_end(4);
                 buffer.set_duration(4.into());
             }
-            Sample::new::<GenericFormattedValue>(Some(&buffer), None, None, None)
+            Sample::new().buffer(&buffer).build()
         };
 
         // `Sample`'s `Segment` is allocated in GStreamer 1.x, should be fixed in version 2.0
@@ -354,12 +361,12 @@ mod tests {
                 .field("f3", &123i32)
                 .build();
 
-            Sample::new::<GenericFormattedValue>(
-                Some(&buffer),
-                Some(&caps),
-                Some(&segment),
-                Some(info),
-            )
+            Sample::new()
+                .buffer(&buffer)
+                .caps(&caps)
+                .segment(&segment)
+                .info(info)
+                .build()
         };
         let sample_ser = ron::ser::to_string(&sample).unwrap();
         let sample_de: Sample = ron::de::from_str(sample_ser.as_str()).unwrap();

gstreamer/src/tags_serde.rs

@@ -323,7 +323,6 @@ mod tests {
 
     use tags::*;
     use Buffer;
-    use GenericFormattedValue;
     use Sample;
     use TagMergeMode;
     use TagScope;
@@ -354,7 +353,7 @@ mod tests {
                     buffer.set_offset(0);
                     buffer.set_offset_end(0);
                 }
-                Sample::new::<GenericFormattedValue>(Some(&buffer), None, None, None)
+                Sample::new().buffer(&buffer).build()
             };
             tags.add::<Image>(&sample, TagMergeMode::Append); // Sample
         }
@@ -569,7 +568,7 @@ mod tests {
                     buffer.set_offset(0);
                     buffer.set_offset_end(0);
                 }
-                Sample::new::<GenericFormattedValue>(Some(&buffer), None, None, None)
+                Sample::new().buffer(&buffer).build()
             };
             tags.add::<Image>(&sample, TagMergeMode::Append); // Sample
         }