Implement multinames, sans runtime namespace support.

core/src/avm2/names.rs

@@ -1,5 +1,6 @@
 //! AVM2 names & namespacing
 
+use crate::avm2::Avm2;
 use gc_arena::Collect;
 use swf::avm2::types::{AbcFile, Index, Multiname as AbcMultiname, Namespace as AbcNamespace};
 
@@ -70,3 +71,59 @@ pub struct QName {
     ns: Namespace,
     name: String,
 }
+
+/// A `Multiname` consists of a name which could be resolved in one or more
+/// potential namespaces.
+///
+/// All unresolved names are of the form `Multiname`, and the name resolution
+/// process consists of searching each name space for a given name.
+pub struct Multiname {
+    ns: Vec<Namespace>,
+    name: String,
+}
+
+impl Multiname {
+    /// Read a multiname from the ABC constant pool, copying it into the most
+    /// general form of multiname.
+    ///
+    /// This does not yet support late-bound or runtime multinames.
+    pub fn from_abc_multiname(
+        file: &AbcFile,
+        multiname_index: Index<Multiname>,
+        avm: &mut Avm2<'_>,
+    ) -> Option<Self> {
+        Some(
+            match file
+                .constant_pool
+                .multinames
+                .get(multiname_index.0 as usize)?
+            {
+                AbcMultiname::QName { namespace, name }
+                | AbcMultiname::QNameA { namespace, name } => Self {
+                    ns: vec![Namespace::from_abc_namespace(file, namespace.clone())?],
+                    name: file.constant_pool.strings.get(name.0 as usize)?.clone(),
+                },
+                AbcMultiname::Multiname {
+                    namespace_set,
+                    name,
+                }
+                | AbcMultiname::MultinameA {
+                    namespace_set,
+                    name,
+                } => Self {
+                    ns: file
+                        .constant_pool
+                        .namespace_sets
+                        .get(namespace_set.0 as usize)?
+                        .iter()
+                        .map(|ns| Namespace::from_abc_namespace(file, ns.clone()))
+                        .filter(|ns| ns.is_some())
+                        .map(|ns| ns.unwrap())
+                        .collect(),
+                    name: file.constant_pool.strings.get(name.0 as usize)?.clone(),
+                },
+                _ => return None,
+            },
+        )
+    }
+}