Fix Dictionary::get unsoundness and add a few convenience functions

Author: Waridley

gdnative-core/src/core_types/dictionary.rs

@@ -69,21 +69,56 @@ impl<Access: ThreadAccess> Dictionary<Access> {
         unsafe { (get_api().godot_dictionary_has_all)(self.sys(), keys.sys()) }
     }
 
-    /// Returns a copy of the value corresponding to the key.
+    /// Returns a copy of the value corresponding to the key, or `Nil` if it doesn't exist.
     #[inline]
     pub fn get<K>(&self, key: K) -> Variant
     where
         K: ToVariant + ToVariantEq,
+    {
+        self.get_or(Variant::new(), key)
+    }
+
+    /// Returns a copy of the value corresponding to the key, or `default` if it doesn't exist
+    #[inline]
+    pub fn get_or<K, D>(&self, default: D, key: K) -> Variant
+    where
+        K: ToVariant + ToVariantEq,
+        D: ToVariant + ToVariantEq,
     {
         unsafe {
-            Variant((get_api().godot_dictionary_get)(
+            Variant((get_api().godot_dictionary_get_with_default)(
                 self.sys(),
                 key.to_variant().sys(),
+                default.to_variant().sys(),
             ))
         }
     }
 
-    /// Update an existing element corresponding ot the key.
+    /// Returns a copy of the element corresponding to the key if it exists.
+    #[inline]
+    pub fn try_get<K>(&self, key: K) -> Option<Variant>
+    where
+        K: ToVariant + ToVariantEq,
+    {
+        let key = key.to_variant();
+        self.contains(key.clone()).then(|| self.get(key))
+    }
+
+    /// Returns a copy of the element corresponding to the key if it exists and is not `Nil`.
+    #[inline]
+    pub fn get_non_nil<K>(&self, key: K) -> Option<Variant>
+    where
+        K: ToVariant + ToVariantEq,
+    {
+        let result = self.get(key);
+        if result.is_nil() {
+            None
+        } else {
+            Some(result)
+        }
+    }
+
+    /// Update an existing element corresponding to the key.
     ///
     /// # Panics
     ///
@@ -266,6 +301,19 @@ impl Dictionary<Shared> {
     pub unsafe fn clear(&self) {
         (get_api().godot_dictionary_clear)(self.sys_mut())
     }
+
+    /// Returns a copy of the value corresponding to the key, inserting `Nil` first if it does not exist.
+    #[doc_variant_collection_safety]
+    #[inline]
+    pub unsafe fn get_or_insert_nil<K>(&self, key: K) -> Variant
+    where
+        K: ToVariant + ToVariantEq,
+    {
+        Variant((get_api().godot_dictionary_get)(
+            self.sys(),
+            key.to_variant().sys(),
+        ))
+    }
 }
 
 /// Operations allowed on Dictionaries that may only be shared on the current thread.
@@ -327,6 +375,20 @@ impl<Access: LocalThreadAccess> Dictionary<Access> {
     pub fn clear(&self) {
         unsafe { (get_api().godot_dictionary_clear)(self.sys_mut()) }
     }
+
+    /// Returns a copy of the value corresponding to the key, inserting `Nil` first if it does not exist.
+    #[inline]
+    pub fn get_or_insert_nil<K>(&self, key: K) -> Variant
+    where
+        K: ToVariant + ToVariantEq,
+    {
+        unsafe {
+            Variant((get_api().godot_dictionary_get)(
+                self.sys(),
+                key.to_variant().sys(),
+            ))
+        }
+    }
 }
 
 /// Operations allowed on unique Dictionaries.