ID3v2: populate popularimeter tag from frame value (#64)

Co-authored-by: Serial <[email protected]>

Author: maneac

src/id3/v2/frame/content.rs

@@ -12,6 +12,7 @@ use std::io::{Cursor, Read};
 
 use byteorder::ReadBytesExt;
 
+#[rustfmt::skip]
 pub(super) fn parse_content(
 	content: &mut &[u8],
 	id: &str,
@@ -32,7 +33,7 @@ pub(super) fn parse_content(
 		// WFED (Podcast URL), GRP1 (Grouping), MVNM (Movement Name), MVIN (Movement Number)
 		"WFED" | "GRP1" | "MVNM" | "MVIN" => parse_text(content, version)?,
 		_ if id.starts_with('W') => parse_link(content)?,
-		"POPM" => Some(parse_popularimeter(content)?),
+		"POPM" => Some(FrameValue::Popularimeter(Popularimeter::from_bytes(content)?)),
 		// SYLT, GEOB, and any unknown frames
 		_ => Some(FrameValue::Binary(content.to_vec())),
 	})
@@ -160,29 +161,6 @@ fn parse_link(content: &mut &[u8]) -> Result<Option<FrameValue>> {
 	Ok(Some(FrameValue::URL(link)))
 }
 
-fn parse_popularimeter(content: &mut &[u8]) -> Result<FrameValue> {
-	let email = decode_text(content, TextEncoding::Latin1, true)?;
-	let rating = content.read_u8()?;
-
-	let counter;
-	let remaining_size = content.len();
-	if remaining_size > 8 {
-		counter = u64::MAX;
-	} else {
-		let mut counter_bytes = [0; 8];
-		let counter_start_pos = 8 - remaining_size;
-
-		counter_bytes[counter_start_pos..].copy_from_slice(content);
-		counter = u64::from_be_bytes(counter_bytes);
-	}
-
-	Ok(FrameValue::Popularimeter(Popularimeter {
-		email: email.unwrap_or_default(),
-		rating,
-		counter,
-	}))
-}
-
 fn verify_encoding(encoding: u8, version: ID3v2Version) -> Result<TextEncoding> {
 	if let ID3v2Version::V2 = version {
 		if encoding != 0 && encoding != 1 {

src/id3/v2/frame/mod.rs

@@ -296,6 +296,9 @@ impl From<TagItem> for Option<Frame> {
 							content: text,
 						})
 					},
+					(FrameID::Valid(ref s), ItemValue::Binary(text)) if s == "POPM" => {
+						FrameValue::Popularimeter(Popularimeter::from_bytes(&text).ok()?)
+					},
 					(_, value) => value.into(),
 				};
 
@@ -394,6 +397,9 @@ impl<'a> TryFrom<&'a TagItem> for FrameRef<'a> {
 					description: String::new(),
 					content: text.clone(),
 				}),
+				("POPM", ItemValue::Binary(contents)) => {
+					FrameValue::Popularimeter(Popularimeter::from_bytes(contents)?)
+				},
 				(_, value) => value.into(),
 			}),
 			flags: FrameFlags::default(),

src/id3/v2/items/popularimeter.rs

@@ -1,5 +1,7 @@
-use crate::util::text::{encode_text, TextEncoding};
+use crate::error::Result;
+use crate::util::text::{decode_text, encode_text, TextEncoding};
 
+use byteorder::ReadBytesExt;
 use std::hash::{Hash, Hasher};
 
 /// The contents of a popularimeter ("POPM") frame
@@ -45,6 +47,32 @@ impl Popularimeter {
 
 		content
 	}
+
+	/// Convert ID3v2 POPM frame bytes into a [`Popularimeter`].
+	pub fn from_bytes(mut bytes: &[u8]) -> Result<Self> {
+		let content = &mut bytes;
+
+		let email = decode_text(content, TextEncoding::Latin1, true)?;
+		let rating = content.read_u8()?;
+
+		let counter;
+		let remaining_size = content.len();
+		if remaining_size > 8 {
+			counter = u64::MAX;
+		} else {
+			let mut counter_bytes = [0; 8];
+			let counter_start_pos = 8 - remaining_size;
+
+			counter_bytes[counter_start_pos..].copy_from_slice(content);
+			counter = u64::from_be_bytes(counter_bytes);
+		}
+
+		Ok(Self {
+			email: email.unwrap_or_default(),
+			rating,
+			counter,
+		})
+	}
 }
 
 impl PartialEq for Popularimeter {

src/id3/v2/tag.rs

@@ -81,6 +81,7 @@ macro_rules! impl_accessor {
 /// * TXXX/WXXX - These frames will be stored as an [`ItemKey`] by their description. Some variants exist for these descriptions, such as the one for `ReplayGain`,
 /// otherwise [`ItemKey::Unknown`] will be used.
 /// * Any [`LanguageFrame`] - With ID3v2 being the only format that allows for language-specific items, this information is not retained. These frames **will** be discarded.
+/// * POPM - These frames will be stored as a raw [`ItemValue::Binary`] value under the [`ItemKey::Popularimeter`] key.
 ///
 /// ## Special Frames
 ///
@@ -571,7 +572,9 @@ impl From<ID3v2Tag> for Tag {
 							tag.push_picture(picture);
 							continue;
 						},
-						FrameValue::Popularimeter(_) => continue,
+						FrameValue::Popularimeter(popularimeter) => {
+							ItemValue::Binary(popularimeter.as_bytes())
+						},
 						FrameValue::Binary(binary) => ItemValue::Binary(binary),
 					};
 
@@ -827,6 +830,58 @@ mod tests {
 		crate::tag::utils::test_utils::verify_tag(&tag, true, true);
 	}
 
+	#[test]
+	fn id3v2_to_tag_popm() {
+		let id3v2 = read_tag("tests/tags/assets/id3v2/test_popm.id3v24");
+
+		let tag: Tag = id3v2.into();
+
+		assert_eq!(
+			tag.get_binary(&ItemKey::Popularimeter, false),
+			Some(
+				&[
+					b'f', b'o', b'o', b'@', b'b', b'a', b'r', b'.', b'c', b'o', b'm', 0, 196, 0, 0,
+					255, 255,
+				][..]
+			),
+		);
+	}
+
+	#[test]
+	fn tag_to_id3v2_popm() {
+		let mut tag = Tag::new(TagType::ID3v2);
+		tag.insert_item(TagItem::new(
+			ItemKey::Popularimeter,
+			ItemValue::Binary(vec![
+				b'f', b'o', b'o', b'@', b'b', b'a', b'r', b'.', b'c', b'o', b'm', 0, 196, 0, 0,
+				255, 255,
+			]),
+		));
+
+		let expected = Popularimeter {
+			email: String::from("[email protected]"),
+			rating: 196,
+			counter: 65535,
+		};
+
+		let converted_tag: ID3v2Tag = tag.into();
+
+		assert_eq!(converted_tag.frames.len(), 1);
+		let actual_frame = converted_tag.frames.first().unwrap();
+
+		assert_eq!(actual_frame.id, FrameID::Valid("POPM".to_string()));
+		// Note: as POPM frames are considered equal by email alone, each field must
+		// be separately validated
+		match actual_frame.content() {
+			FrameValue::Popularimeter(pop) => {
+				assert_eq!(pop.email, expected.email);
+				assert_eq!(pop.rating, expected.rating);
+				assert_eq!(pop.counter, expected.counter);
+			},
+			_ => unreachable!(),
+		}
+	}
+
 	#[test]
 	fn fail_write_bad_frame() {
 		let mut tag = ID3v2Tag::default();