From 55c2d410405bf7519bbdf47a4346ecd50a1f7d18 Mon Sep 17 00:00:00 2001
From: trivernis <trivernis@protonmail.com>
Date: Sun, 13 Mar 2022 18:49:22 +0100
Subject: [PATCH] Add is and implements functions

Signed-off-by: trivernis <trivernis@protonmail.com>
---
 Cargo.toml   |  2 +-
 src/lib.rs   | 28 +++++++++++++++++++++++++++-
 src/tests.rs |  8 ++++++++
 3 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index db28c1c..58bd6b8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "multi-trait-object"
-version = "0.1.1"
+version = "0.1.2"
 edition = "2021"
 readme = "README.md"
 license = "Apache-2.0"
diff --git a/src/lib.rs b/src/lib.rs
index 6c76cfc..e10ffce 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -94,12 +94,14 @@ impl MultitraitObject {
     }
 
     /// Downcasts the object into a reference of the given type
+    #[inline]
     pub fn downcast_ref<T: Any>(&self) -> Option<&T> {
         let any = self.downcast_trait::<dyn Any>().unwrap();
         any.downcast_ref::<T>()
     }
 
     /// Downcasts the object into a mutable reference of the given type
+    #[inline]
     pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
         let any = self.downcast_trait_mut::<dyn Any>().unwrap();
         any.downcast_mut::<T>()
@@ -120,12 +122,28 @@ impl MultitraitObject {
         }
     }
 
+    /// Returns if the object stores the given concrete type
+    /// Use [MultitraitObject::implements] to check if the object
+    /// has a given trait
+    #[inline]
+    pub fn is<T: Any>(&self) -> bool {
+        self.original_typeid == TypeId::of::<T>()
+    }
+
+    /// Returns if the object implements a given trait
+    #[inline]
+    pub fn implements<T: 'static + ?Sized>(&self) -> bool {
+        self.traits.contains_key(&TypeId::of::<T>())
+    }
+
     #[doc(hidden)]
+    #[inline]
     pub fn _register<T2: 'static + ?Sized>(&mut self, vtable_ptr: *const ()) {
         self.traits.insert(TypeId::of::<T2>(), vtable_ptr);
     }
 
     #[doc(hidden)]
+    #[inline]
     unsafe fn _downcast_trait<T1: 'static + ?Sized>(&self) -> Option<&T1> {
         // SAFETY: Creating a fat pointer from the given v-table and data has no side effects
         let vptr = *self.traits.get(&TypeId::of::<T1>())?;
@@ -136,6 +154,7 @@ impl MultitraitObject {
     }
 
     #[doc(hidden)]
+    #[inline]
     unsafe fn _downcast_trait_mut<T1: 'static + ?Sized>(&mut self) -> Option<&mut T1> {
         // SAFETY: Creating a fat pointer from the given v-table and data has no side effects
         let vptr = *self.traits.get(&TypeId::of::<T1>())?;
@@ -146,6 +165,7 @@ impl MultitraitObject {
     }
 
     #[doc(hidden)]
+    #[inline]
     unsafe fn _downcast_boxed_trait<T1: 'static + ?Sized>(&mut self) -> Option<Box<T1>> {
         // SAFETY: Creating a fat pointer from the given v-table and data has no side effects
         let vptr = *self.traits.get(&TypeId::of::<T1>())?;
@@ -160,7 +180,7 @@ impl MultitraitObject {
 impl Drop for MultitraitObject {
     fn drop(&mut self) {
         unsafe {
-            // Safety: The Multitrait object has exclusive access to the data pointer
+            // SAFETY: The Multitrait object has exclusive access to the data pointer
             let raw = Box::from_raw(self.data);
             std::mem::drop(raw);
         }
@@ -171,6 +191,12 @@ pub trait IntoMultitrait {
     fn into_multitrait(self) -> MultitraitObject;
 }
 
+impl<T> From<T> for MultitraitObject where T: IntoMultitrait {
+    fn from(other: T) -> Self {
+        other.into_multitrait()
+    }
+}
+
 pub mod prelude {
     pub use crate::*;
 }
\ No newline at end of file
diff --git a/src/tests.rs b/src/tests.rs
index 4459eff..9046d85 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -86,4 +86,12 @@ fn it_tries_cloning() {
     let obj1 = mto.downcast::<TestStruct>();
     let obj2 = mto2.downcast::<TestStruct>();
     assert_eq!(obj1, obj2);
+}
+
+#[test]
+fn it_returns_type_information() {
+    let mto = TestStruct::default().into_multitrait();
+    assert!(mto.is::<TestStruct>());
+    assert!(mto.implements::<dyn Debug>());
+    assert!(mto.implements::<dyn ChangeStruct>());
 }
\ No newline at end of file