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Diffstat (limited to 'src/model/collapse.rs')
| -rw-r--r-- | src/model/collapse.rs | 116 |
1 files changed, 0 insertions, 116 deletions
diff --git a/src/model/collapse.rs b/src/model/collapse.rs deleted file mode 100644 index f57a3a42..00000000 --- a/src/model/collapse.rs +++ /dev/null @@ -1,116 +0,0 @@ -use super::{StyleChain, StyleVec, StyleVecBuilder}; - -/// A wrapper around a [`StyleVecBuilder`] that allows to collapse items. -pub(super) struct CollapsingBuilder<'a, T> { - /// The internal builder. - builder: StyleVecBuilder<'a, T>, - /// Staged weak and ignorant items that we can't yet commit to the builder. - /// The option is `Some(_)` for weak items and `None` for ignorant items. - staged: Vec<(T, StyleChain<'a>, Option<u8>)>, - /// What the last non-ignorant item was. - last: Last, -} - -/// What the last non-ignorant item was. -#[derive(Debug, Copy, Clone, Eq, PartialEq)] -enum Last { - Weak, - Destructive, - Supportive, -} - -impl<'a, T> CollapsingBuilder<'a, T> { - /// Create a new style-vec builder. - pub fn new() -> Self { - Self { - builder: StyleVecBuilder::new(), - staged: vec![], - last: Last::Destructive, - } - } - - /// Whether the builder is empty. - pub fn is_empty(&self) -> bool { - self.builder.is_empty() && self.staged.is_empty() - } - - /// Can only exist when there is at least one supportive item to its left - /// and to its right, with no destructive items in between. There may be - /// ignorant items in between in both directions. - /// - /// Between weak items, there may be at least one per layer and among the - /// candidates the strongest one (smallest `weakness`) wins. When tied, - /// the one that compares larger through `PartialOrd` wins. - pub fn weak(&mut self, item: T, styles: StyleChain<'a>, weakness: u8) - where - T: PartialOrd, - { - if self.last == Last::Destructive { - return; - } - - if self.last == Last::Weak { - if let Some(i) = - self.staged.iter().position(|(prev_item, _, prev_weakness)| { - prev_weakness.map_or(false, |prev_weakness| { - weakness < prev_weakness - || (weakness == prev_weakness && item > *prev_item) - }) - }) - { - self.staged.remove(i); - } else { - return; - } - } - - self.staged.push((item, styles, Some(weakness))); - self.last = Last::Weak; - } - - /// Forces nearby weak items to collapse. - pub fn destructive(&mut self, item: T, styles: StyleChain<'a>) { - self.flush(false); - self.builder.push(item, styles); - self.last = Last::Destructive; - } - - /// Allows nearby weak items to exist. - pub fn supportive(&mut self, item: T, styles: StyleChain<'a>) { - self.flush(true); - self.builder.push(item, styles); - self.last = Last::Supportive; - } - - /// Has no influence on other items. - pub fn ignorant(&mut self, item: T, styles: StyleChain<'a>) { - self.staged.push((item, styles, None)); - } - - /// Iterate over the contained items. - pub fn items(&self) -> impl DoubleEndedIterator<Item = &T> { - self.builder.items().chain(self.staged.iter().map(|(item, ..)| item)) - } - - /// Return the finish style vec and the common prefix chain. - pub fn finish(mut self) -> (StyleVec<T>, StyleChain<'a>) { - self.flush(false); - self.builder.finish() - } - - /// Push the staged items, filtering out weak items if `supportive` is - /// false. - fn flush(&mut self, supportive: bool) { - for (item, styles, meta) in self.staged.drain(..) { - if supportive || meta.is_none() { - self.builder.push(item, styles); - } - } - } -} - -impl<'a, T> Default for CollapsingBuilder<'a, T> { - fn default() -> Self { - Self::new() - } -} |
