all: GObject builders: generalise property_from_str

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1594>

gstreamer-app/src/app_sink.rs

@@ -512,9 +512,13 @@ impl AppSink {
     /// Creates a new builder-pattern struct instance to construct [`AppSink`] objects.
     ///
     /// This method returns an instance of [`AppSinkBuilder`](crate::builders::AppSinkBuilder) which can be used to create [`AppSink`] objects.
-    pub fn builder() -> AppSinkBuilder {
+    pub fn builder<'a>() -> AppSinkBuilder<'a> {
         assert_initialized_main_thread!();
-        AppSinkBuilder::new()
+        AppSinkBuilder {
+            builder: gst::Object::builder(),
+            callbacks: None,
+            drop_out_of_segment: None,
+        }
     }
 
     #[doc(alias = "gst_app_sink_set_callbacks")]
@@ -1173,26 +1177,23 @@ impl AppSink {
 ///
 /// [builder-pattern]: https://doc.rust-lang.org/1.0.0/style/ownership/builders.html
 #[must_use = "The builder must be built to be used"]
-pub struct AppSinkBuilder {
+pub struct AppSinkBuilder<'a> {
-    builder: glib::object::ObjectBuilder<'static, AppSink>,
+    builder: gst::gobject::GObjectBuilder<'a, AppSink>,
     callbacks: Option<AppSinkCallbacks>,
     drop_out_of_segment: Option<bool>,
 }
 
-impl AppSinkBuilder {
+impl<'a> AppSinkBuilder<'a> {
-    fn new() -> Self {
-        Self {
-            builder: glib::Object::builder(),
-            callbacks: None,
-            drop_out_of_segment: None,
-        }
-    }
-
     // rustdoc-stripper-ignore-next
     /// Build the [`AppSink`].
+    ///
+    /// # Panics
+    ///
+    /// This panics if the [`AppSink`] doesn't have all the given properties or
+    /// property values of the wrong type are provided.
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> AppSink {
-        let appsink = self.builder.build();
+        let appsink = self.builder.build().unwrap();
 
         if let Some(callbacks) = self.callbacks {
             appsink.set_callbacks(callbacks);
@@ -1226,7 +1227,7 @@ impl AppSinkBuilder {
         }
     }
 
-    pub fn caps(self, caps: &gst::Caps) -> Self {
+    pub fn caps(self, caps: &'a gst::Caps) -> Self {
         Self {
             builder: self.builder.property("caps", caps),
             ..self
@@ -1350,12 +1351,29 @@ impl AppSinkBuilder {
         }
     }
 
-    pub fn name(self, name: impl Into<glib::GString>) -> Self {
+    // rustdoc-stripper-ignore-next
+    /// Sets property `name` to the given value `value`.
+    ///
+    /// Overrides any default or previously defined value for `name`.
+    #[inline]
+    pub fn property(self, name: &'a str, value: impl Into<glib::Value> + 'a) -> Self {
         Self {
-            builder: self.builder.property("name", name.into()),
+            builder: self.builder.property(name, value),
             ..self
         }
     }
+
+    // rustdoc-stripper-ignore-next
+    /// Sets property `name` to the given string value `value`.
+    #[inline]
+    pub fn property_from_str(self, name: &'a str, value: &'a str) -> Self {
+        Self {
+            builder: self.builder.property_from_str(name, value),
+            ..self
+        }
+    }
+
+    gst::impl_builder_gvalue_extra_setters!(property_and_name);
 }
 
 #[derive(Debug)]

gstreamer-app/src/app_src.rs

@@ -311,9 +311,13 @@ impl AppSrc {
     /// Creates a new builder-pattern struct instance to construct [`AppSrc`] objects.
     ///
     /// This method returns an instance of [`AppSrcBuilder`](crate::builders::AppSrcBuilder) which can be used to create [`AppSrc`] objects.
-    pub fn builder() -> AppSrcBuilder {
+    pub fn builder<'a>() -> AppSrcBuilder<'a> {
         assert_initialized_main_thread!();
-        AppSrcBuilder::new()
+        AppSrcBuilder {
+            builder: gst::Object::builder(),
+            callbacks: None,
+            automatic_eos: None,
+        }
     }
 
     #[doc(alias = "gst_app_src_set_callbacks")]
@@ -453,26 +457,23 @@ impl AppSrc {
 ///
 /// [builder-pattern]: https://doc.rust-lang.org/1.0.0/style/ownership/builders.html
 #[must_use = "The builder must be built to be used"]
-pub struct AppSrcBuilder {
+pub struct AppSrcBuilder<'a> {
-    builder: glib::object::ObjectBuilder<'static, AppSrc>,
+    builder: gst::gobject::GObjectBuilder<'a, AppSrc>,
     callbacks: Option<AppSrcCallbacks>,
     automatic_eos: Option<bool>,
 }
 
-impl AppSrcBuilder {
+impl<'a> AppSrcBuilder<'a> {
-    fn new() -> Self {
-        Self {
-            builder: glib::Object::builder(),
-            callbacks: None,
-            automatic_eos: None,
-        }
-    }
-
     // rustdoc-stripper-ignore-next
     /// Build the [`AppSrc`].
+    ///
+    /// # Panics
+    ///
+    /// This panics if the [`AppSrc`] doesn't have all the given properties or
+    /// property values of the wrong type are provided.
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> AppSrc {
-        let appsrc = self.builder.build();
+        let appsrc = self.builder.build().unwrap();
 
         if let Some(callbacks) = self.callbacks {
             appsrc.set_callbacks(callbacks);
@@ -506,7 +507,7 @@ impl AppSrcBuilder {
         }
     }
 
-    pub fn caps(self, caps: &gst::Caps) -> Self {
+    pub fn caps(self, caps: &'a gst::Caps) -> Self {
         Self {
             builder: self.builder.property("caps", caps),
             ..self
@@ -621,12 +622,29 @@ impl AppSrcBuilder {
         }
     }
 
-    pub fn name(self, name: impl Into<glib::GString>) -> Self {
+    // rustdoc-stripper-ignore-next
+    /// Sets property `name` to the given value `value`.
+    ///
+    /// Overrides any default or previously defined value for `name`.
+    #[inline]
+    pub fn property(self, name: &'a str, value: impl Into<glib::Value> + 'a) -> Self {
         Self {
-            builder: self.builder.property("name", name.into()),
+            builder: self.builder.property(name, value),
             ..self
         }
     }
+
+    // rustdoc-stripper-ignore-next
+    /// Sets property `name` to the given string value `value`.
+    #[inline]
+    pub fn property_from_str(self, name: &'a str, value: &'a str) -> Self {
+        Self {
+            builder: self.builder.property_from_str(name, value),
+            ..self
+        }
+    }
+
+    gst::impl_builder_gvalue_extra_setters!(property_and_name);
 }
 
 #[derive(Debug)]
@@ -792,4 +810,37 @@ mod tests {
             sample_quantity
         );
     }
+
+    #[test]
+    fn builder_caps_lt() {
+        gst::init().unwrap();
+
+        let caps = &gst::Caps::new_any();
+        {
+            let stream_type = "random-access".to_owned();
+            let appsrc = AppSrc::builder()
+                .property_from_str("stream-type", &stream_type)
+                .caps(caps)
+                .build();
+            assert_eq!(
+                appsrc.property::<crate::AppStreamType>("stream-type"),
+                crate::AppStreamType::RandomAccess
+            );
+            assert!(appsrc.property::<gst::Caps>("caps").is_any());
+        }
+
+        let stream_type = &"random-access".to_owned();
+        {
+            let caps = &gst::Caps::new_any();
+            let appsrc = AppSrc::builder()
+                .property_from_str("stream-type", stream_type)
+                .caps(caps)
+                .build();
+            assert_eq!(
+                appsrc.property::<crate::AppStreamType>("stream-type"),
+                crate::AppStreamType::RandomAccess
+            );
+            assert!(appsrc.property::<gst::Caps>("caps").is_any());
+        }
+    }
 }

gstreamer/src/bin.rs

@@ -37,8 +37,11 @@ impl Bin {
     /// Creates a new builder-pattern struct instance to construct [`Bin`] objects.
     ///
     /// This method returns an instance of [`BinBuilder`] which can be used to create [`Bin`] objects.
-    pub fn builder() -> BinBuilder {
+    pub fn builder<'a>() -> BinBuilder<'a> {
-        BinBuilder::new()
+        assert_initialized_main_thread!();
+        BinBuilder {
+            builder: crate::Object::builder(),
+        }
     }
 }
 
@@ -221,22 +224,21 @@ impl Default for Bin {
 ///
 /// [builder-pattern]: https://doc.rust-lang.org/1.0.0/style/ownership/builders.html
 #[must_use = "The builder must be built to be used"]
-pub struct BinBuilder {
+pub struct BinBuilder<'a> {
-    builder: glib::object::ObjectBuilder<'static, Bin>,
+    builder: crate::gobject::GObjectBuilder<'a, Bin>,
 }
 
-impl BinBuilder {
+impl<'a> BinBuilder<'a> {
-    fn new() -> Self {
-        Self {
-            builder: glib::Object::builder(),
-        }
-    }
-
     // rustdoc-stripper-ignore-next
     /// Build the [`Bin`].
+    ///
+    /// # Panics
+    ///
+    /// This panics if the [`Bin`] doesn't have all the given properties or
+    /// property values of the wrong type are provided.
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Bin {
-        self.builder.build()
+        self.builder.build().unwrap()
     }
 
     pub fn async_handling(self, async_handling: bool) -> Self {
@@ -267,27 +269,27 @@ impl BinBuilder {
         }
     }
 
-    pub fn name(self, name: impl Into<glib::GString>) -> Self {
+    // rustdoc-stripper-ignore-next
+    /// Sets property `name` to the given value `value`.
+    ///
+    /// Overrides any default or previously defined value for `name`.
+    #[inline]
+    pub fn property(self, name: &'a str, value: impl Into<glib::Value> + 'a) -> Self {
         Self {
-            builder: self.builder.property("name", name.into()),
+            builder: self.builder.property(name, value),
         }
     }
 
-    pub fn name_if(self, name: impl Into<glib::GString>, predicate: bool) -> Self {
+    // rustdoc-stripper-ignore-next
-        if predicate {
+    /// Sets property `name` to the given string value `value`.
-            self.name(name)
+    #[inline]
-        } else {
+    pub fn property_from_str(self, name: &'a str, value: &'a str) -> Self {
-            self
+        Self {
+            builder: self.builder.property_from_str(name, value),
         }
     }
 
-    pub fn name_if_some(self, name: Option<impl Into<glib::GString>>) -> Self {
+    impl_builder_gvalue_extra_setters!(property_and_name);
-        if let Some(name) = name {
-            self.name(name)
-        } else {
-            self
-        }
-    }
 }
 
 unsafe extern "C" fn do_latency_trampoline<
@@ -346,4 +348,20 @@ mod tests {
             vec![String::from("identity0"), String::from("identity1")]
         );
     }
+
+    #[test]
+    fn builder() {
+        crate::init().unwrap();
+
+        let msg_fwd = "message-forward";
+        let bin = Bin::builder()
+            .name("test-bin")
+            .property("async-handling", true)
+            .property_from_str(msg_fwd, "True")
+            .build();
+
+        assert_eq!(bin.name(), "test-bin");
+        assert!(bin.property::<bool>("async-handling"));
+        assert!(bin.property::<bool>("message-forward"));
+    }
 }

gstreamer/src/element_factory.rs

@@ -16,10 +16,9 @@ impl ElementFactory {
     #[track_caller]
     pub fn create(&self) -> ElementBuilder {
         assert_initialized_main_thread!();
-
         ElementBuilder {
             name_or_factory: NameOrFactory::Factory(self),
-            properties: smallvec::SmallVec::new(),
+            builder: crate::Object::builder_for_deferred_type(),
         }
     }
 
@@ -28,10 +27,9 @@ impl ElementFactory {
     #[track_caller]
     pub fn make(factoryname: &str) -> ElementBuilder {
         assert_initialized_main_thread!();
-
         ElementBuilder {
             name_or_factory: NameOrFactory::Name(factoryname),
-            properties: smallvec::SmallVec::new(),
+            builder: crate::Object::builder_for_deferred_type(),
         }
     }
 
@@ -190,7 +188,7 @@ impl ElementFactory {
 #[must_use = "The builder must be built to be used"]
 pub struct ElementBuilder<'a> {
     name_or_factory: NameOrFactory<'a>,
-    properties: smallvec::SmallVec<[(&'a str, ValueOrStr<'a>); 16]>,
+    builder: crate::gobject::GObjectBuilder<'a, Element>,
 }
 
 #[derive(Copy, Clone)]
@@ -199,30 +197,7 @@ enum NameOrFactory<'a> {
     Factory(&'a ElementFactory),
 }
 
-enum ValueOrStr<'a> {
-    Value(glib::Value),
-    Str(&'a str),
-}
-
 impl<'a> ElementBuilder<'a> {
-    // rustdoc-stripper-ignore-next
-    /// Sets the name property to the given `name`.
-    #[inline]
-    pub fn name(self, name: impl Into<glib::GString>) -> Self {
-        self.property("name", name.into())
-    }
-
-    // rustdoc-stripper-ignore-next
-    /// Sets the name property to the given `name` if it is `Some`.
-    #[inline]
-    pub fn name_if_some(self, name: Option<impl Into<glib::GString>>) -> Self {
-        if let Some(name) = name {
-            self.name(name)
-        } else {
-            self
-        }
-    }
-
     // rustdoc-stripper-ignore-next
     /// Sets property `name` to the given value `value`.
     ///
@@ -230,51 +205,34 @@ impl<'a> ElementBuilder<'a> {
     #[inline]
     pub fn property(self, name: &'a str, value: impl Into<glib::Value> + 'a) -> Self {
         Self {
-            name_or_factory: self.name_or_factory,
+            builder: self.builder.property(name, value),
-            properties: {
+            ..self
-                let mut properties = self.properties;
-                properties.push((name, ValueOrStr::Value(value.into())));
-                properties
-            },
         }
     }
 
-    impl_builder_gvalue_extra_setters!(property);
-
     // rustdoc-stripper-ignore-next
     /// Sets property `name` to the given string value `value`.
     #[inline]
     pub fn property_from_str(self, name: &'a str, value: &'a str) -> Self {
         Self {
-            name_or_factory: self.name_or_factory,
+            builder: self.builder.property_from_str(name, value),
-            properties: {
+            ..self
-                let mut properties = self.properties;
-                properties.push((name, ValueOrStr::Str(value)));
-                properties
-            },
         }
     }
 
-    // rustdoc-stripper-ignore-next
+    impl_builder_gvalue_extra_setters!(property_and_name);
-    /// Sets property `name` to the given string value `value` if it is `Some`.
-    #[inline]
-    pub fn property_from_str_if_some(self, name: &'a str, value: Option<&'a str>) -> Self {
-        if let Some(value) = value {
-            self.property_from_str(name, value)
-        } else {
-            self
-        }
-    }
 
     // rustdoc-stripper-ignore-next
-    /// Builds the element with the provided properties.
+    /// Builds the [`Element`] with the provided properties.
     ///
-    /// This fails if there is no such element factory or the element factory can't be loaded.
+    /// This fails if there is no such [`ElementFactory`] or the [`ElementFactory`] can't be loaded.
     ///
     /// # Panics
     ///
-    /// This panics if the element is not instantiable, doesn't have all the given properties or
+    /// This panics if the [`Element`] is not instantiable, doesn't have all the given properties or
     /// property values of the wrong type are provided.
+    ///
+    /// [`Element`]: crate::Element
     #[track_caller]
     #[must_use = "Building the element without using it has no effect"]
     pub fn build(self) -> Result<Element, glib::BoolError> {
@@ -328,68 +286,21 @@ impl<'a> ElementBuilder<'a> {
             ));
         }
 
-        let mut properties = smallvec::SmallVec::<[_; 16]>::with_capacity(self.properties.len());
+        let element = self
-        let klass = glib::Class::<Element>::from_type(element_type).unwrap();
+            .builder
-        for (name, value) in self.properties {
+            .type_(element_type)
-            match value {
+            .build()
-                ValueOrStr::Value(value) => {
+            .map_err(|err| {
-                    properties.push((name, value));
+                use crate::gobject::GObjectError::*;
+                match err {
+                    PropertyNotFound { property, .. } => {
+                        format!("property '{property}' of element factory '{}' not found", factory.name())
+                    },
+                    PropertyFromStr { property, value, .. } => {
+                        format!("property '{property}' of element factory '{}' can't be set from string '{value}'", factory.name())
+                    },
                 }
-                ValueOrStr::Str(value) => {
+            }).unwrap();
-                    use crate::value::GstValueExt;
-
-                    let pspec = match klass.find_property(name) {
-                        Some(pspec) => pspec,
-                        None => {
-                            panic!(
-                                "property '{}' of element factory '{}' not found",
-                                name,
-                                factory.name()
-                            );
-                        }
-                    };
-
-                    let value = {
-                        if pspec.value_type() == crate::Structure::static_type() && value == "NULL"
-                        {
-                            None::<crate::Structure>.to_value()
-                        } else {
-                            #[cfg(feature = "v1_20")]
-                            {
-                                glib::Value::deserialize_with_pspec(value, &pspec)
-                                    .unwrap_or_else(|_| {
-                                        panic!(
-                                            "property '{}' of element factory '{}' can't be set from string '{}'",
-                                            name,
-                                            factory.name(),
-                                            value,
-                                        )
-                                    })
-                            }
-                            #[cfg(not(feature = "v1_20"))]
-                            {
-                                glib::Value::deserialize(value, pspec.value_type())
-                                    .unwrap_or_else(|_| {
-                                        panic!(
-                                            "property '{}' of element factory '{}' can't be set from string '{}'",
-                                            name,
-                                            factory.name(),
-                                            value,
-                                        )
-                                    })
-                            }
-                        }
-                    };
-
-                    properties.push((name, value));
-                }
-            }
-        }
-
-        let element = unsafe {
-            glib::Object::with_mut_values(element_type, &mut properties)
-                .unsafe_cast::<crate::Element>()
-        };
 
         unsafe {
             use std::sync::atomic;
@@ -430,3 +341,27 @@ impl<'a> ElementBuilder<'a> {
         Ok(element)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::prelude::*;
+
+    #[test]
+    fn builder() {
+        crate::init().unwrap();
+
+        let fakesink = ElementFactory::make("fakesink")
+            .name("test-fakesink")
+            .property("can-activate-pull", true)
+            .property_from_str("state-error", "ready-to-paused")
+            .build()
+            .unwrap();
+
+        assert_eq!(fakesink.name(), "test-fakesink");
+        assert!(fakesink.property::<bool>("can-activate-pull"));
+        let v = fakesink.property_value("state-error");
+        let (_klass, e) = glib::EnumValue::from_value(&v).unwrap();
+        assert_eq!(e.nick(), "ready-to-paused");
+    }
+}

gstreamer/src/gobject.rs

@@ -1,8 +1,98 @@
 // Take a look at the license at the top of the repository in the LICENSE file.
 
-use glib::prelude::*;
+use std::marker::PhantomData;
 
-use crate::value::GstValueExt;
+use glib::{object::IsClass, prelude::*, Type};
+
+use crate::{value::GstValueExt, IdStr};
+
+impl crate::Object {
+    // rustdoc-stripper-ignore-next
+    /// Builds a `GObjectBuilder` targeting type `O`.
+    #[inline]
+    pub fn builder<'a, O>() -> GObjectBuilder<'a, O>
+    where
+        O: IsA<crate::Object> + IsClass,
+    {
+        assert_initialized_main_thread!();
+        GObjectBuilder {
+            type_: Some(O::static_type()),
+            properties: smallvec::SmallVec::new(),
+            phantom: PhantomData,
+        }
+    }
+
+    // rustdoc-stripper-ignore-next
+    /// Builds a `GObjectBuilder` targeting base class of type `O` and concrete `type_`.
+    #[inline]
+    pub fn builder_for<'a, O>(type_: Type) -> GObjectBuilder<'a, O>
+    where
+        O: IsA<crate::Object> + IsClass,
+    {
+        assert_initialized_main_thread!();
+        GObjectBuilder {
+            type_: Some(type_),
+            properties: smallvec::SmallVec::new(),
+            phantom: PhantomData,
+        }
+    }
+
+    // rustdoc-stripper-ignore-next
+    /// Builds a `GObjectBuilder` targeting base class of type `O`
+    /// and a concrete `Type` that will be specified later.
+    ///
+    /// This is useful when the concrete type of the object is dynamically determined
+    /// when calling the `build()` method of a wrapping builder.
+    #[inline]
+    pub fn builder_for_deferred_type<'a, O>() -> GObjectBuilder<'a, O>
+    where
+        O: IsA<crate::Object> + IsClass,
+    {
+        assert_initialized_main_thread!();
+        GObjectBuilder {
+            type_: None,
+            properties: smallvec::SmallVec::new(),
+            phantom: PhantomData,
+        }
+    }
+}
+
+#[derive(Debug, Eq, PartialEq, thiserror::Error)]
+pub enum GObjectError {
+    #[error("property {property} for type {type_} not found")]
+    PropertyNotFound { type_: Type, property: IdStr },
+
+    #[error("property {property} for type {type_} can't be set from string {value}")]
+    PropertyFromStr {
+        type_: Type,
+        property: IdStr,
+        value: IdStr,
+    },
+}
+
+fn value_from_property_str(
+    pspec: glib::ParamSpec,
+    value: &str,
+) -> Result<glib::Value, GObjectError> {
+    skip_assert_initialized!(); // Already checked transitively by caller
+
+    if pspec.value_type() == crate::Structure::static_type() && value == "NULL" {
+        Ok(None::<crate::Structure>.to_value())
+    } else {
+        cfg_if::cfg_if! {
+            if #[cfg(feature = "v1_20")] {
+                let res = glib::Value::deserialize_with_pspec(value, &pspec);
+            } else {
+                let res = glib::Value::deserialize(value, pspec.value_type());
+            }
+        }
+        res.map_err(|_| GObjectError::PropertyFromStr {
+            type_: pspec.owner_type(),
+            property: pspec.name().into(),
+            value: value.into(),
+        })
+    }
+}
 
 pub trait GObjectExtManualGst: IsA<glib::Object> + 'static {
     #[doc(alias = "gst_util_set_object_arg")]
@@ -12,53 +102,192 @@ pub trait GObjectExtManualGst: IsA<glib::Object> + 'static {
             panic!("property '{}' of type '{}' not found", name, self.type_());
         });
 
-        let value = {
+        self.set_property(name, value_from_property_str(pspec, value).unwrap())
-            if pspec.value_type() == crate::Structure::static_type() && value == "NULL" {
-                None::<crate::Structure>.to_value()
-            } else {
-                #[cfg(feature = "v1_20")]
-                {
-                    glib::Value::deserialize_with_pspec(value, &pspec).unwrap_or_else(|_| {
-                        panic!(
-                            "property '{}' of type '{}' can't be set from string '{}'",
-                            name,
-                            self.type_(),
-                            value,
-                        )
-                    })
-                }
-                #[cfg(not(feature = "v1_20"))]
-                {
-                    glib::Value::deserialize(value, pspec.value_type()).unwrap_or_else(|_| {
-                        panic!(
-                            "property '{}' of type '{}' can't be set from string '{}'",
-                            name,
-                            self.type_(),
-                            value,
-                        )
-                    })
-                }
-            }
-        };
-
-        self.set_property(name, value)
     }
 }
 
 impl<O: IsA<glib::Object>> GObjectExtManualGst for O {}
 
+// rustdoc-stripper-ignore-next
+/// Builder for `GObject`s.
+#[must_use = "The builder must be built to be used"]
+pub struct GObjectBuilder<'a, O> {
+    type_: Option<Type>,
+    properties: smallvec::SmallVec<[(&'a str, ValueOrStr<'a>); 16]>,
+    phantom: PhantomData<O>,
+}
+
+enum ValueOrStr<'a> {
+    Value(glib::Value),
+    Str(&'a str),
+}
+
+impl<'a, O: IsA<crate::Object> + IsClass> GObjectBuilder<'a, O> {
+    // rustdoc-stripper-ignore-next
+    /// Sets the concrete `Type`.
+    ///
+    /// This should be used on an `GObjectBuilder` created with
+    /// [`GObjectBuilder::for_deferred_type`].
+    #[inline]
+    pub fn type_(mut self, type_: Type) -> Self {
+        self.type_ = Some(type_);
+        self
+    }
+
+    // rustdoc-stripper-ignore-next
+    /// Sets property `name` to the given value `value`.
+    ///
+    /// Overrides any default or previously defined value for `name`.
+    #[inline]
+    pub fn property(self, name: &'a str, value: impl Into<glib::Value> + 'a) -> Self {
+        Self {
+            properties: {
+                let mut properties = self.properties;
+                properties.push((name, ValueOrStr::Value(value.into())));
+                properties
+            },
+            ..self
+        }
+    }
+
+    // rustdoc-stripper-ignore-next
+    /// Sets property `name` to the given string value `value`.
+    #[inline]
+    pub fn property_from_str(self, name: &'a str, value: &'a str) -> Self {
+        Self {
+            properties: {
+                let mut properties = self.properties;
+                properties.push((name, ValueOrStr::Str(value)));
+                properties
+            },
+            ..self
+        }
+    }
+
+    impl_builder_gvalue_extra_setters!(property_and_name);
+
+    // rustdoc-stripper-ignore-next
+    /// Builds the [`Object`] with the provided properties.
+    ///
+    /// This fails if there is no such element factory or the element factory can't be loaded.
+    ///
+    /// # Panics
+    ///
+    /// This panics if:
+    ///
+    /// * The [`Object`] is not instantiable, doesn't have all the given properties or
+    ///   property values of the wrong type are provided.
+    /// * The [`GObjectBuilder`] was created for a deferred concrete `Type` but
+    ///   the `Type` was not set.
+    ///
+    /// [`Object`]: crate::Object
+    #[track_caller]
+    #[must_use = "Building the element without using it has no effect"]
+    pub fn build(self) -> Result<O, GObjectError> {
+        let type_ = self.type_.expect("Deferred Type must be set");
+
+        let mut properties = smallvec::SmallVec::<[_; 16]>::with_capacity(self.properties.len());
+        let klass = glib::Class::<O>::from_type(type_).unwrap();
+        for (name, value) in self.properties {
+            let pspec =
+                klass
+                    .find_property(name)
+                    .ok_or_else(|| GObjectError::PropertyNotFound {
+                        type_,
+                        property: name.into(),
+                    })?;
+
+            match value {
+                ValueOrStr::Value(value) => properties.push((name, value)),
+                ValueOrStr::Str(value) => {
+                    properties.push((name, value_from_property_str(pspec, value)?));
+                }
+            }
+        }
+
+        let object =
+            unsafe { glib::Object::with_mut_values(type_, &mut properties).unsafe_cast::<O>() };
+
+        Ok(object)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::{prelude::*, Bin, Element, ElementFactory, Object};
 
     #[test]
     fn test_set_property_from_str() {
         crate::init().unwrap();
 
-        let fakesink = crate::ElementFactory::make("fakesink").build().unwrap();
+        let fakesink = ElementFactory::make("fakesink").build().unwrap();
         fakesink.set_property_from_str("state-error", "ready-to-paused");
         let v = fakesink.property_value("state-error");
         let (_klass, e) = glib::EnumValue::from_value(&v).unwrap();
         assert_eq!(e.nick(), "ready-to-paused");
     }
+
+    #[test]
+    fn builder() {
+        crate::init().unwrap();
+
+        let msg_fwd = "message-forward";
+        let bin = Object::builder::<Bin>()
+            .name("test-bin")
+            .property("async-handling", true)
+            .property_from_str(msg_fwd, "True")
+            .build()
+            .unwrap();
+
+        assert_eq!(bin.name(), "test-bin");
+        assert!(bin.property::<bool>("async-handling"));
+        assert!(bin.property::<bool>("message-forward"));
+    }
+
+    #[test]
+    fn builder_err() {
+        crate::init().unwrap();
+
+        assert_eq!(
+            Object::builder::<Bin>()
+                .property("not-a-prop", true)
+                .build(),
+            Err(GObjectError::PropertyNotFound {
+                type_: Bin::static_type(),
+                property: idstr!("not-a-prop")
+            })
+        );
+
+        assert_eq!(
+            Object::builder::<Bin>()
+                .property_from_str("async-handling", "not-a-bool")
+                .build(),
+            Err(GObjectError::PropertyFromStr {
+                type_: Bin::static_type(),
+                property: idstr!("async-handling"),
+                value: idstr!("not-a-bool")
+            })
+        );
+    }
+
+    #[test]
+    fn builder_for() {
+        crate::init().unwrap();
+
+        let fakesink = ElementFactory::make("fakesink").build().unwrap();
+
+        let fakesink = Object::builder_for::<Element>(fakesink.type_())
+            .name("test-fakesink")
+            .property("can-activate-pull", true)
+            .property_from_str("state-error", "ready-to-paused")
+            .build()
+            .unwrap();
+
+        assert_eq!(fakesink.name(), "test-fakesink");
+        assert!(fakesink.property::<bool>("can-activate-pull"));
+        let v = fakesink.property_value("state-error");
+        let (_klass, e) = glib::EnumValue::from_value(&v).unwrap();
+        assert_eq!(e.nick(), "ready-to-paused");
+    }
 }

gstreamer/src/lib.rs

@@ -200,7 +200,7 @@ mod device_provider;
 mod device_provider_factory;
 mod enums;
 mod ghost_pad;
-mod gobject;
+pub mod gobject;
 mod iterator;
 mod object;
 mod pad;

gstreamer/src/pipeline.rs

@@ -35,8 +35,11 @@ impl Pipeline {
     /// Creates a new builder-pattern struct instance to construct [`Pipeline`] objects.
     ///
     /// This method returns an instance of [`PipelineBuilder`] which can be used to create [`Pipeline`] objects.
-    pub fn builder() -> PipelineBuilder {
+    pub fn builder<'a>() -> PipelineBuilder<'a> {
-        PipelineBuilder::new()
+        assert_initialized_main_thread!();
+        PipelineBuilder {
+            builder: crate::Object::builder(),
+        }
     }
 }
 
@@ -80,22 +83,21 @@ impl Default for Pipeline {
 ///
 /// [builder-pattern]: https://doc.rust-lang.org/1.0.0/style/ownership/builders.html
 #[must_use = "The builder must be built to be used"]
-pub struct PipelineBuilder {
+pub struct PipelineBuilder<'a> {
-    builder: glib::object::ObjectBuilder<'static, Pipeline>,
+    builder: crate::gobject::GObjectBuilder<'a, Pipeline>,
 }
 
-impl PipelineBuilder {
+impl<'a> PipelineBuilder<'a> {
-    fn new() -> Self {
-        Self {
-            builder: glib::Object::builder(),
-        }
-    }
-
     // rustdoc-stripper-ignore-next
     /// Build the [`Pipeline`].
+    ///
+    /// # Panics
+    ///
+    /// This panics if the [`Pipeline`] doesn't have all the given properties or
+    /// property values of the wrong type are provided.
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Pipeline {
-        self.builder.build()
+        self.builder.build().unwrap()
     }
 
     pub fn auto_flush_bus(self, auto_flush_bus: bool) -> Self {
@@ -188,25 +190,25 @@ impl PipelineBuilder {
         }
     }
 
-    pub fn name(self, name: impl Into<glib::GString>) -> Self {
+    // rustdoc-stripper-ignore-next
+    /// Sets property `name` to the given value `value`.
+    ///
+    /// Overrides any default or previously defined value for `name`.
+    #[inline]
+    pub fn property(self, name: &'a str, value: impl Into<glib::Value> + 'a) -> Self {
         Self {
-            builder: self.builder.property("name", name.into()),
+            builder: self.builder.property(name, value),
         }
     }
 
-    pub fn name_if(self, name: impl Into<glib::GString>, predicate: bool) -> Self {
+    // rustdoc-stripper-ignore-next
-        if predicate {
+    /// Sets property `name` to the given string value `value`.
-            self.name(name)
+    #[inline]
-        } else {
+    pub fn property_from_str(self, name: &'a str, value: &'a str) -> Self {
-            self
+        Self {
+            builder: self.builder.property_from_str(name, value),
         }
     }
 
-    pub fn name_if_some(self, name: Option<impl Into<glib::GString>>) -> Self {
+    impl_builder_gvalue_extra_setters!(property_and_name);
-        if let Some(name) = name {
-            self.name(name)
-        } else {
-            self
-        }
-    }
 }

gstreamer/src/value.rs

@@ -1714,7 +1714,7 @@ macro_rules! impl_builder_gvalue_extra_setters (
         }
      };
 
-    (property) => {
+    (property_and_name) => {
         // rustdoc-stripper-ignore-next
         /// Sets property `name` to the given inner value if the `predicate` evaluates to `true`.
         ///
@@ -1775,6 +1775,67 @@ macro_rules! impl_builder_gvalue_extra_setters (
                 self
             }
         }
+
+        // rustdoc-stripper-ignore-next
+        /// Sets property `name` to the given string value `value` if the `predicate` evaluates to `true`.
+        ///
+        /// This has no effect if the `predicate` evaluates to `false`,
+        /// i.e. default or previous value for `name` is kept.
+        #[inline]
+        pub fn property_from_str_if(self, name: &'a str, value: &'a str, predicate: bool) -> Self {
+            if predicate {
+                self.property_from_str(name, value)
+            } else {
+                self
+            }
+        }
+
+        // rustdoc-stripper-ignore-next
+        /// Sets property `name` to the given string value `value` if it is `Some`.
+        ///
+        /// This has no effect if the value is `None`, i.e. default or previous value for `name` is kept.
+        #[inline]
+        pub fn property_from_str_if_some(self, name: &'a str, value: Option<&'a str>) -> Self {
+            if let Some(value) = value {
+                self.property_from_str(name, value)
+            } else {
+                self
+            }
+        }
+
+        // rustdoc-stripper-ignore-next
+        /// Sets the name property to the given `name`.
+        #[inline]
+        pub fn name(self, name: impl Into<$crate::glib::GString>) -> Self {
+            self.property("name", name.into())
+        }
+
+        // rustdoc-stripper-ignore-next
+        /// Sets the name property to the given `name` if the `predicate` evaluates to `true`.
+        ///
+        /// This has no effect if the `predicate` evaluates to `false`,
+        /// i.e. default or previous name is kept.
+        #[inline]
+        pub fn name_if(self, name: impl Into<$crate::glib::GString>, predicate: bool) -> Self {
+            if predicate {
+                self.name(name)
+            } else {
+                self
+            }
+        }
+
+        // rustdoc-stripper-ignore-next
+        /// Sets the name property to the given `name` if it is `Some`.
+        ///
+        /// This has no effect if the value is `None`, i.e. default or previous name is kept.
+        #[inline]
+        pub fn name_if_some(self, name: Option<impl Into<$crate::glib::GString>>) -> Self {
+            if let Some(name) = name {
+                self.name(name)
+            } else {
+                self
+            }
+        }
      };
 );