1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321
use std::borrow::Cow;
// This defines the `Accessor` trait, used to define unified getters/setters for commonly
// accessed tag values.
//
// Usage:
//
// accessor_trait! {
// [field_name]<type>
// }
//
// * `field_name` is the name of the method to access the field. If a name consists of multiple segments,
// such as `track_number`, they should be separated by spaces like so: [track number]<type>.
//
// * `type` is the return type for `Accessor::field_name`. By default, this type will also be used
// in the setter.
//
// An owned type can also be specified for the setter:
//
// accessor_trait! {
// field_name<type, owned_type>
// }
macro_rules! accessor_trait {
($([$($name:tt)+] < $($ty:ty),+ >),+ $(,)?) => {
/// Provides accessors for common items
///
/// This attempts to only provide methods for items that all tags have in common,
/// but there may be exceptions.
pub trait Accessor {
$(
accessor_trait! { @GETTER [$($name)+] $($ty),+ }
accessor_trait! { @SETTER [$($name)+] $($ty),+ }
accessor_trait! { @REMOVE [$($name)+] $($ty),+ }
)+
}
};
(@GETTER [$($name:tt)+] $ty:ty $(, $_ty:tt)?) => {
accessor_trait! { @GET_METHOD [$($name)+] Option<$ty> }
};
(@SETTER [$($name:tt)+] $_ty:ty, $owned_ty:tt) => {
accessor_trait! { @SETTER [$($name)+] $owned_ty }
};
(@SETTER [$($name:tt)+] $ty:ty) => {
accessor_trait! { @SET_METHOD [$($name)+] $ty }
};
(@REMOVE [$($name:tt)+] $_ty:ty, $owned_ty:tt) => {
accessor_trait! { @REMOVE [$($name)+] $owned_ty }
};
(@REMOVE [$($name:tt)+] $ty:ty) => {
accessor_trait! { @REMOVE_METHOD [$($name)+], $ty }
};
(@GET_METHOD [$name:tt $($other:tt)*] Option<$ret_ty:ty>) => {
paste::paste! {
#[doc = "Returns the " $name $(" " $other)*]
/// # Example
///
/// ```rust
/// use lofty::{Tag, Accessor};
///
/// # let tag_type = lofty::TagType::Id3v2;
/// let mut tag = Tag::new(tag_type); ///
#[doc = "assert_eq!(tag." $name $(_ $other)* "(), None);"]
/// ```
fn [<
$name $(_ $other)*
>] (&self) -> Option<$ret_ty> { None }
}
};
(@SET_METHOD [$name:tt $($other:tt)*] $owned_ty:ty) => {
paste::paste! {
#[doc = "Sets the " $name $(" " $other)*]
/// # Example
///
/// ```rust,ignore
/// use lofty::{Tag, Accessor};
///
/// let mut tag = Tag::new(tag_type);
#[doc = "tag.set_" $name $(_ $other)* "(value);"]
///
#[doc = "assert_eq!(tag." $name $(_ $other)* "(), Some(value));"]
/// ```
fn [<
set_ $name $(_ $other)*
>] (&mut self , _value: $owned_ty) {}
}
};
(@REMOVE_METHOD [$name:tt $($other:tt)*], $ty:ty) => {
paste::paste! {
#[doc = "Removes the " $name $(" " $other)*]
/// # Example
///
/// ```rust,ignore
/// use lofty::{Tag, Accessor};
///
/// let mut tag = Tag::new(tag_type);
#[doc = "tag.set_" $name $(_ $other)* "(value);"]
///
#[doc = "assert_eq!(tag." $name $(_ $other)* "(), Some(value));"]
///
#[doc = "tag.remove_" $name $(_ $other)* "();"]
///
#[doc = "assert_eq!(tag." $name $(_ $other)* "(), None);"]
/// ```
fn [<
remove_ $name $(_ $other)*
>] (&mut self) {}
}
};
}
accessor_trait! {
[artist]<Cow<'_, str>, String>, [title ]<Cow<'_, str>, String>,
[album ]<Cow<'_, str>, String>, [genre ]<Cow<'_, str>, String>,
[track ]<u32>, [track total]<u32>,
[disk ]<u32>, [disk total ]<u32>,
[year ]<u32>, [comment ]<Cow<'_, str>, String>,
}
use crate::tag::Tag;
use std::fs::File;
use std::path::Path;
/// A set of common methods between tags
///
/// This provides a set of methods to make interaction with all tags a similar
/// experience.
///
/// This can be implemented downstream to provide a familiar interface for custom tags.
pub trait TagExt: Accessor + Into<Tag> + Sized {
/// The associated error which can be returned from IO operations
type Err: From<std::io::Error>;
/// The type of key used in the tag for non-mutating functions
type RefKey<'a>
where
Self: 'a;
/// Returns the number of items in the tag
///
/// This will also include any extras, such as pictures.
///
/// # Example
///
/// ```rust
/// use lofty::{Accessor, ItemKey, Tag, TagExt};
/// # let tag_type = lofty::TagType::Id3v2;
///
/// let mut tag = Tag::new(tag_type);
/// assert_eq!(tag.len(), 0);
///
/// tag.set_artist(String::from("Foo artist"));
/// assert_eq!(tag.len(), 1);
/// ```
fn len(&self) -> usize;
/// Whether the tag contains an item with the key
///
/// # Example
///
/// ```rust
/// use lofty::{Accessor, ItemKey, Tag, TagExt};
/// # let tag_type = lofty::TagType::Id3v2;
///
/// let mut tag = Tag::new(tag_type);
/// assert!(tag.is_empty());
///
/// tag.set_artist(String::from("Foo artist"));
/// assert!(tag.contains(&ItemKey::TrackArtist));
/// ```
fn contains<'a>(&'a self, key: Self::RefKey<'a>) -> bool;
/// Whether the tag has any items
///
/// # Example
///
/// ```rust
/// use lofty::{Accessor, Tag, TagExt};
/// # let tag_type = lofty::TagType::Id3v2;
///
/// let mut tag = Tag::new(tag_type);
/// assert!(tag.is_empty());
///
/// tag.set_artist(String::from("Foo artist"));
/// assert!(!tag.is_empty());
/// ```
fn is_empty(&self) -> bool;
/// Save the tag to a path
///
/// # Errors
///
/// * Path doesn't exist
/// * Path is not writable
/// * See [`TagExt::save_to`]
fn save_to_path<P: AsRef<Path>>(&self, path: P) -> std::result::Result<(), Self::Err> {
self.save_to(
&mut std::fs::OpenOptions::new()
.read(true)
.write(true)
.open(path)?,
)
}
/// Save the tag to a [`File`]
///
/// # Errors
///
/// * The file format could not be determined
/// * Attempting to write a tag to a format that does not support it.
fn save_to(&self, file: &mut File) -> std::result::Result<(), Self::Err>;
#[allow(clippy::missing_errors_doc)]
/// Dump the tag to a writer
///
/// This will only write the tag, it will not produce a usable file.
fn dump_to<W: std::io::Write>(&self, writer: &mut W) -> std::result::Result<(), Self::Err>;
/// Remove a tag from a [`Path`]
///
/// # Errors
///
/// See [`TagExt::remove_from`]
fn remove_from_path<P: AsRef<Path>>(&self, path: P) -> std::result::Result<(), Self::Err>;
/// Remove a tag from a [`File`]
///
/// # Errors
///
/// * It is unable to guess the file format
/// * The format doesn't support the tag
/// * It is unable to write to the file
fn remove_from(&self, file: &mut File) -> std::result::Result<(), Self::Err>;
/// Clear the tag, removing all items
///
/// NOTE: This will **not** remove any format-specific extras, such as flags
fn clear(&mut self);
}
/// Split (and merge) tags.
///
/// Useful and required for implementing lossless read/modify/write round trips.
/// Its counterpart `MergeTag` is used for recombining the results later.
///
/// # Example
///
/// ```no_run
/// use lofty::mpeg::MpegFile;
/// use lofty::{AudioFile, ItemKey, MergeTag as _, SplitTag as _};
///
/// // Read the tag from a file
/// # let mut file = std::fs::OpenOptions::new().write(true).open("/path/to/file.mp3")?;
/// # let parse_options = lofty::ParseOptions::default();
/// let mut mpeg_file = <MpegFile as AudioFile>::read_from(&mut file, parse_options)?;
/// let mut id3v2 = mpeg_file
/// .id3v2_mut()
/// .map(std::mem::take)
/// .unwrap_or_default();
///
/// // Split: ID3v2 -> [`lofty::Tag`]
/// let (mut remainder, mut tag) = id3v2.split_tag();
///
/// // Modify the metadata in the generic [`lofty::Tag`], independent
/// // of the underlying tag and file format.
/// tag.insert_text(ItemKey::TrackTitle, "Track Title".to_owned());
/// tag.remove_key(&ItemKey::Composer);
///
/// // ID3v2 <- [`lofty::Tag`]
/// let id3v2 = remainder.merge_tag(tag);
///
/// // Write the changes back into the file
/// mpeg_file.set_id3v2(id3v2);
/// mpeg_file.save_to(&mut file)?;
///
/// # Ok::<(), lofty::LoftyError>(())
/// ```
pub trait SplitTag {
/// The remainder of the split operation that is not represented
/// in the resulting `Tag`.
type Remainder: MergeTag;
/// Extract and split generic contents into a [`Tag`].
///
/// Returns the remaining content that cannot be represented in the
/// resulting `Tag` in `Self::Remainder`. This is useful if the
/// modified [`Tag`] is merged later using [`MergeTag::merge_tag`].
fn split_tag(self) -> (Self::Remainder, Tag);
}
/// The counterpart of [`SplitTag`].
pub trait MergeTag {
/// The resulting tag.
type Merged: SplitTag;
/// Merge a generic [`Tag`] back into the remainder of [`SplitTag::split_tag`].
///
/// Restores the original representation merged with the contents of
/// `tag` for further processing, e.g. writing back into a file.
///
/// Multi-valued items in `tag` with identical keys might get lost
/// depending on the support for multi-valued fields in `self`.
fn merge_tag(self, tag: Tag) -> Self::Merged;
}
// TODO: https://github.com/rust-lang/rust/issues/59359
pub(crate) trait SeekStreamLen: std::io::Seek {
fn stream_len(&mut self) -> crate::error::Result<u64> {
use std::io::SeekFrom;
let current_pos = self.stream_position()?;
let len = self.seek(SeekFrom::End(0))?;
self.seek(SeekFrom::Start(current_pos))?;
Ok(len)
}
}
impl<T> SeekStreamLen for T where T: std::io::Seek {}