MP4: Implement TryFrom<ItemKey> for AtomIdent

CHANGELOG.md

@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- **MP4**: `AtomIdent` now implements `TryFrom<ItemKey>`
+
 ## [0.10.0] - 2022-12-27
 
 ### Added

src/mp4/atom_info.rs

@@ -1,5 +1,7 @@
 use crate::error::{ErrorKind, LoftyError, Result};
 use crate::macros::{err, try_vec};
+use crate::tag::item::ItemKey;
+use crate::tag::TagType;
 
 use std::borrow::Cow;
 use std::io::{Read, Seek, SeekFrom};
@@ -54,6 +56,49 @@ impl<'a> AtomIdent<'a> {
 	}
 }
 
+impl<'a> TryFrom<&'a ItemKey> for AtomIdent<'a> {
+	type Error = LoftyError;
+
+	fn try_from(value: &'a ItemKey) -> std::result::Result<Self, Self::Error> {
+		if let Some(mapped_key) = value.map_key(TagType::MP4ilst, true) {
+			if mapped_key.starts_with("----") {
+				let mut split = mapped_key.split(':');
+
+				split.next();
+
+				let mean = split.next();
+				let name = split.next();
+
+				if let (Some(mean), Some(name)) = (mean, name) {
+					return Ok(AtomIdent::Freeform {
+						mean: Cow::Borrowed(mean),
+						name: Cow::Borrowed(name),
+					});
+				}
+			} else {
+				let fourcc = mapped_key.chars().map(|c| c as u8).collect::<Vec<_>>();
+
+				if let Ok(fourcc) = TryInto::<[u8; 4]>::try_into(fourcc) {
+					return Ok(AtomIdent::Fourcc(fourcc));
+				}
+			}
+		}
+
+		err!(TextDecode(
+			"ItemKey does not map to a freeform or fourcc identifier"
+		))
+	}
+}
+
+impl TryFrom<ItemKey> for AtomIdent<'static> {
+	type Error = LoftyError;
+
+	fn try_from(value: ItemKey) -> std::result::Result<Self, Self::Error> {
+		let ret: AtomIdent<'_> = (&value).try_into()?;
+		Ok(ret.into_owned())
+	}
+}
+
 pub(crate) struct AtomInfo {
 	pub(crate) start: u64,
 	pub(crate) len: u64,

src/mp4/ilst/mod.rs

@@ -454,7 +454,7 @@ impl From<Tag> for Ilst {
 		for item in input.items {
 			let key = item.item_key;
 
-			if let Some(ident) = item_key_to_ident(&key) {
+			if let Ok(ident) = TryInto::<AtomIdent<'_>>::try_into(&key) {
 				let data = match item.item_value {
 					ItemValue::Text(text) => text,
 					_ => continue,
@@ -491,36 +491,6 @@ impl From<Tag> for Ilst {
 	}
 }
 
-fn item_key_to_ident(key: &ItemKey) -> Option<AtomIdent<'_>> {
-	key.map_key(TagType::MP4ilst, true).and_then(|ident| {
-		if ident.starts_with("----") {
-			let mut split = ident.split(':');
-
-			split.next();
-
-			let mean = split.next();
-			let name = split.next();
-
-			if let (Some(mean), Some(name)) = (mean, name) {
-				Some(AtomIdent::Freeform {
-					mean: Cow::Borrowed(mean),
-					name: Cow::Borrowed(name),
-				})
-			} else {
-				None
-			}
-		} else {
-			let fourcc = ident.chars().map(|c| c as u8).collect::<Vec<_>>();
-
-			if let Ok(fourcc) = TryInto::<[u8; 4]>::try_into(fourcc) {
-				Some(AtomIdent::Fourcc(fourcc))
-			} else {
-				None
-			}
-		}
-	})
-}
-
 #[cfg(test)]
 mod tests {
 	use crate::mp4::ilst::atom::AtomDataStorage;