Include frame ID in text decoding error messages

[NebuPookins]

When an ID3v2 text frame contains malformed UTF-16 content (e.g. odd byte length), lofty surfaces an error like: Text decoding: UTF-16 string has an odd length

I'm not very familiar with Rust, but I think the frame ID is available in parse_frame (in src/id3/v2/frame/read.rs) when parse_content fails, but is dropped by the ? operator:

fn parse_frame<R: Read>(
  reader: &mut R,
  size: u32,
  id: FrameId<'static>,
  ...
) -> Result<ParsedFrame<'static>> {
  match parse_content(reader, id, flags, version, parse_mode)? {  // id lost on error

The fix might be something like adding context to the error before propagating:

  parse_content(reader, id.clone(), flags, version, parse_mode)
  .map_err(|e| e.context(format!("In frame '{}'", id)))?

This would produce a message like:

Text decoding: UTF-16 string has an odd length (in frame 'TIT2')

..which makes it much easier for applications and end users to identify and fix the problematic tag without having to reimplement raw ID3 byte scanning themselves.

[Serial-ATA]

Yeah, there's lots of room for improvement in Lofty's errors. Especially in TextDecode, TooMuchData, SizeMismatch, and BadAtom.

When I get some time I'll look into refactoring Error to hold a chain of errors instead, so you could get a FrameParse error that wraps a child TextDecode error.

That'd make messages like this possible:

Failed to parse 'TIT2' frame

Caused by: UTF-16 string has an odd length

[Serial-ATA]

@NebuPookins I've been experimenting with retaining error sources on the errors branch: https://github.com/Serial-ATA/lofty-rs/tree/errors

So far only Id3v2Tag, Id3v1Tag, and MpegFile parsing have full error traces. It's a huge refactor, so it'll probably be awhile before I can get it out.

You can now get nice error messages like:

failed to parse Mpeg file
Caused by: failed to parse ID3v2 tag
Caused by: failed to parse frame 'TPE1'
Caused by: failed to decode UTF-16 sequence: UTF-16 string has an invalid byte order mark

With a basic reporter like this:

fn report(mut err: &(dyn std::error::Error + 'static)) -> String {
	use std::fmt::Write;
	let mut s = format!("{err}");
	while let Some(src) = err.source() {
		let _ = write!(s, "\nCaused by: {src}");
		err = src;
	}
	s
}

match Probe::open(path).and_then(Probe::read) {
	Ok(_) => {
		println!("Parsed file successfully!");
	},
	Err(e) => {
		eprintln!("{}", report(&e));
	},
};