EBML: Impl some TagExt methods

lofty/src/ebml/mod.rs

@@ -16,7 +16,7 @@ pub use vint::VInt;
 /// An EBML file
 #[derive(LoftyFile, Default)]
 #[lofty(read_fn = "read::read_from")]
-// TODO: #[lofty(internal_write_module_do_not_use_anywhere_else)]
+#[lofty(internal_write_module_do_not_use_anywhere_else)]
 pub struct EbmlFile {
 	/// An EBML tag
 	#[lofty(tag_type = "Ebml")]

lofty/src/ebml/tag/mod.rs

@@ -2,6 +2,7 @@ mod attached_file;
 mod simple_tag;
 mod tag;
 mod target;
+mod write;
 
 pub use attached_file::*;
 pub use simple_tag::*;
@@ -39,15 +40,19 @@ impl TagExt for EbmlTag {
 	}
 
 	fn len(&self) -> usize {
-		todo!()
+		self.tags
+			.iter()
+			.map(|tag| tag.simple_tags.len())
+			.sum::<usize>()
+			+ self.attached_files.len()
 	}
 
 	fn contains<'a>(&'a self, _key: Self::RefKey<'a>) -> bool {
 		todo!()
 	}
 
 	fn is_empty(&self) -> bool {
-		todo!()
+		self.tags.is_empty() && self.attached_files.is_empty()
 	}
 
 	fn save_to<F>(
@@ -85,7 +90,8 @@ impl TagExt for EbmlTag {
 	}
 
 	fn clear(&mut self) {
-		todo!()
+		self.tags.clear();
+		self.attached_files.clear();
 	}
 }
 

lofty/src/ebml/tag/target.rs

@@ -93,3 +93,12 @@ pub struct Target {
 	/// [`AttachedFile::uid`]: crate::ebml::AttachedFile::uid
 	pub attachment_uids: Option<Vec<u64>>,
 }
+
+impl From<TargetType> for Target {
+	fn from(target_type: TargetType) -> Self {
+		Self {
+			target_type,
+			..Default::default()
+		}
+	}
+}

lofty_attr/src/internal.rs

@@ -51,6 +51,8 @@ pub(crate) fn init_write_lookup(
 		.write_to(file, write_options)
 	});
 
+	insert!(map, Ebml, { todo!() });
+
 	insert!(map, Id3v1, {
 		Into::<lofty::id3::v1::tag::Id3v1TagRef<'_>>::into(tag).write_to(file, write_options)
 	});