avm2: Add convenience method for converting a `Value` into an `EnumSet`.

core/src/avm2/value.rs

@@ -8,6 +8,7 @@ use crate::avm2::script::TranslationUnit;
 use crate::avm2::string::AvmString;
 use crate::avm2::{Avm2, Error};
 use crate::ecma_conversions::{f64_to_wrapping_i32, f64_to_wrapping_u32};
+use enumset::{EnumSet, EnumSetType};
 use gc_arena::{Collect, MutationContext};
 use std::cell::Ref;
 use std::f64::NAN;
@@ -445,6 +446,20 @@ impl<'gc> Value<'gc> {
         Ok(f64_to_wrapping_i32(self.coerce_to_number(activation)?))
     }
 
+    /// Coerce the value to an EnumSet of a particular type.
+    ///
+    /// This function will ignore invalid bits of the value when interpreting
+    /// the enum.
+    pub fn coerce_to_enumset<E>(
+        &self,
+        activation: &mut Activation<'_, 'gc, '_>,
+    ) -> Result<EnumSet<E>, Error>
+    where
+        E: EnumSetType,
+    {
+        Ok(EnumSet::from_u32_truncated(self.coerce_to_u32(activation)?))
+    }
+
     /// Mininum number of digits after which numbers are formatted as
     /// exponential strings.
     const MIN_DIGITS: f64 = -6.0;