Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'helix-core/src/text_annotations.rs')
| -rw-r--r-- | helix-core/src/text_annotations.rs | 242 |
1 files changed, 44 insertions, 198 deletions
diff --git a/helix-core/src/text_annotations.rs b/helix-core/src/text_annotations.rs index 0f492b8b..1576914e 100644 --- a/helix-core/src/text_annotations.rs +++ b/helix-core/src/text_annotations.rs @@ -1,12 +1,8 @@ use std::cell::Cell; -use std::cmp::Ordering; -use std::fmt::Debug; use std::ops::Range; -use std::ptr::NonNull; -use crate::doc_formatter::FormattedGrapheme; -use crate::syntax::{Highlight, OverlayHighlights}; -use crate::{Position, Tendril}; +use crate::syntax::Highlight; +use crate::Tendril; /// An inline annotation is continuous text shown /// on the screen before the grapheme that starts at @@ -79,98 +75,19 @@ impl Overlay { } } -/// Line annotations allow inserting virtual text lines between normal text -/// lines. These lines can be filled with text in the rendering code as their -/// contents have no effect beyond visual appearance. +/// Line annotations allow for virtual text between normal +/// text lines. They cause `height` empty lines to be inserted +/// below the document line that contains `anchor_char_idx`. /// -/// The height of virtual text is usually not known ahead of time as virtual -/// text often requires softwrapping. Furthermore the height of some virtual -/// text like side-by-side diffs depends on the height of the text (again -/// influenced by softwrap) and other virtual text. Therefore line annotations -/// are computed on the fly instead of ahead of time like other annotations. +/// These lines can be filled with text in the rendering code +/// as their contents have no effect beyond visual appearance. /// -/// The core of this trait `insert_virtual_lines` function. It is called at the -/// end of every visual line and allows the `LineAnnotation` to insert empty -/// virtual lines. Apart from that the `LineAnnotation` trait has multiple -/// methods that allow it to track anchors in the document. -/// -/// When a new traversal of a document starts `reset_pos` is called. Afterwards -/// the other functions are called with indices that are larger then the -/// one passed to `reset_pos`. This allows performing a binary search (use -/// `partition_point`) in `reset_pos` once and then to only look at the next -/// anchor during each method call. -/// -/// The `reset_pos`, `skip_conceal` and `process_anchor` functions all return a -/// `char_idx` anchor. This anchor is stored when transversing the document and -/// when the grapheme at the anchor is traversed the `process_anchor` function -/// is called. -/// -/// # Note -/// -/// All functions only receive immutable references to `self`. -/// `LineAnnotation`s that want to store an internal position or -/// state of some kind should use `Cell`. Using interior mutability for -/// caches is preferable as otherwise a lot of lifetimes become invariant -/// which complicates APIs a lot. -pub trait LineAnnotation { - /// Resets the internal position to `char_idx`. This function is called - /// when a new traversal of a document starts. - /// - /// All `char_idx` passed to `insert_virtual_lines` are strictly monotonically increasing - /// with the first `char_idx` greater or equal to the `char_idx` - /// passed to this function. - /// - /// # Returns - /// - /// The `char_idx` of the next anchor this `LineAnnotation` is interested in, - /// replaces the currently registered anchor. Return `usize::MAX` to ignore - fn reset_pos(&mut self, _char_idx: usize) -> usize { - usize::MAX - } - - /// Called when a text is concealed that contains an anchor registered by this `LineAnnotation`. - /// In this case the line decorations **must** ensure that virtual text anchored within that - /// char range is skipped. - /// - /// # Returns - /// - /// The `char_idx` of the next anchor this `LineAnnotation` is interested in, - /// **after the end of conceal_end_char_idx** - /// replaces the currently registered anchor. Return `usize::MAX` to ignore - fn skip_concealed_anchors(&mut self, conceal_end_char_idx: usize) -> usize { - self.reset_pos(conceal_end_char_idx) - } - - /// Process an anchor (horizontal position is provided) and returns the next anchor. - /// - /// # Returns - /// - /// The `char_idx` of the next anchor this `LineAnnotation` is interested in, - /// replaces the currently registered anchor. Return `usize::MAX` to ignore - fn process_anchor(&mut self, _grapheme: &FormattedGrapheme) -> usize { - usize::MAX - } - - /// This function is called at the end of a visual line to insert virtual text - /// - /// # Returns - /// - /// The number of additional virtual lines to reserve - /// - /// # Note - /// - /// The `line_end_visual_pos` parameter indicates the visual vertical distance - /// from the start of block where the traversal starts. This includes the offset - /// from other `LineAnnotations`. This allows inline annotations to consider - /// the height of the text and "align" two different documents (like for side - /// by side diffs). These annotations that want to "align" two documents should - /// therefore be added last so that other virtual text is also considered while aligning - fn insert_virtual_lines( - &mut self, - line_end_char_idx: usize, - line_end_visual_pos: Position, - doc_line: usize, - ) -> Position; +/// To insert a line after a document line simply set +/// `anchor_char_idx` to `doc.line_to_char(line_idx)` +#[derive(Debug, Clone)] +pub struct LineAnnotation { + pub anchor_char_idx: usize, + pub height: usize, } #[derive(Debug)] @@ -211,7 +128,7 @@ impl<A, M> Layer<'_, A, M> { } impl<'a, A, M> From<(&'a [A], M)> for Layer<'a, A, M> { - fn from((annotations, metadata): (&'a [A], M)) -> Layer<'a, A, M> { + fn from((annotations, metadata): (&'a [A], M)) -> Layer<A, M> { Layer { annotations, current_index: Cell::new(0), @@ -226,68 +143,13 @@ fn reset_pos<A, M>(layers: &[Layer<A, M>], pos: usize, get_pos: impl Fn(&A) -> u } } -/// Safety: We store LineAnnotation in a NonNull pointer. This is necessary to work -/// around an unfortunate inconsistency in rusts variance system that unnnecesarily -/// makes the lifetime invariant if implemented with safe code. This makes the -/// DocFormatter API very cumbersome/basically impossible to work with. -/// -/// Normally object types `dyn Foo + 'a` are covariant so if we used `Box<dyn LineAnnotation + 'a>` below -/// everything would be alright. However we want to use `Cell<Box<dyn LineAnnotation + 'a>>` -/// to be able to call the mutable function on `LineAnnotation`. The problem is that -/// some types like `Cell` make all their arguments invariant. This is important for soundness -/// normally for the same reasons that `&'a mut T` is invariant over `T` -/// (see <https://doc.rust-lang.org/nomicon/subtyping.html>). However for `&'a mut` (`dyn Foo + 'b`) -/// there is a specical rule in the language to make `'b` covariant (otherwise trait objects would be -/// super annoying to use). See <https://users.rust-lang.org/t/solved-variance-of-dyn-trait-a> for -/// why this is sound. Sadly that rule doesn't apply to `Cell<Box<(dyn Foo + 'a)>` -/// (or other invariant types like `UnsafeCell` or `*mut (dyn Foo + 'a)`). -/// -/// We sidestep the problem by using `NonNull` which is covariant. In the -/// special case of trait objects this is sound (easily checked by adding a -/// `PhantomData<&'a mut Foo + 'a)>` field). We don't need an explicit `Cell` -/// type here because we never hand out any refereces to the trait objects. That -/// means any reference to the pointer can create a valid multable reference -/// that is covariant over `'a` (or in other words it's a raw pointer, as long as -/// we don't hand out references we are free to do whatever we want). -struct RawBox<T: ?Sized>(NonNull<T>); - -impl<T: ?Sized> RawBox<T> { - /// Safety: Only a single mutable reference - /// created by this function may exist at a given time. - #[allow(clippy::mut_from_ref)] - unsafe fn get(&self) -> &mut T { - &mut *self.0.as_ptr() - } -} -impl<T: ?Sized> From<Box<T>> for RawBox<T> { - fn from(box_: Box<T>) -> Self { - // obviously safe because Box::into_raw never returns null - unsafe { Self(NonNull::new_unchecked(Box::into_raw(box_))) } - } -} - -impl<T: ?Sized> Drop for RawBox<T> { - fn drop(&mut self) { - unsafe { drop(Box::from_raw(self.0.as_ptr())) } - } -} - /// Annotations that change that is displayed when the document is render. /// Also commonly called virtual text. -#[derive(Default)] +#[derive(Default, Debug, Clone)] pub struct TextAnnotations<'a> { inline_annotations: Vec<Layer<'a, InlineAnnotation, Option<Highlight>>>, overlays: Vec<Layer<'a, Overlay, Option<Highlight>>>, - line_annotations: Vec<(Cell<usize>, RawBox<dyn LineAnnotation + 'a>)>, -} - -impl Debug for TextAnnotations<'_> { - fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { - f.debug_struct("TextAnnotations") - .field("inline_annotations", &self.inline_annotations) - .field("overlays", &self.overlays) - .finish_non_exhaustive() - } + line_annotations: Vec<Layer<'a, LineAnnotation, ()>>, } impl<'a> TextAnnotations<'a> { @@ -295,12 +157,15 @@ impl<'a> TextAnnotations<'a> { pub fn reset_pos(&self, char_idx: usize) { reset_pos(&self.inline_annotations, char_idx, |annot| annot.char_idx); reset_pos(&self.overlays, char_idx, |annot| annot.char_idx); - for (next_anchor, layer) in &self.line_annotations { - next_anchor.set(unsafe { layer.get().reset_pos(char_idx) }); - } + reset_pos(&self.line_annotations, char_idx, |annot| { + annot.anchor_char_idx + }); } - pub fn collect_overlay_highlights(&self, char_range: Range<usize>) -> OverlayHighlights { + pub fn collect_overlay_highlights( + &self, + char_range: Range<usize>, + ) -> Vec<(usize, Range<usize>)> { let mut highlights = Vec::new(); self.reset_pos(char_range.start); for char_idx in char_range { @@ -308,11 +173,11 @@ impl<'a> TextAnnotations<'a> { // we don't know the number of chars the original grapheme takes // however it doesn't matter as highlight boundaries are automatically // aligned to grapheme boundaries in the rendering code - highlights.push((highlight, char_idx..char_idx + 1)); + highlights.push((highlight.0, char_idx..char_idx + 1)) } } - OverlayHighlights::Heterogenous { highlights } + highlights } /// Add new inline annotations. @@ -331,9 +196,7 @@ impl<'a> TextAnnotations<'a> { layer: &'a [InlineAnnotation], highlight: Option<Highlight>, ) -> &mut Self { - if !layer.is_empty() { - self.inline_annotations.push((layer, highlight).into()); - } + self.inline_annotations.push((layer, highlight).into()); self } @@ -348,9 +211,7 @@ impl<'a> TextAnnotations<'a> { /// If multiple layers contain overlay at the same position /// the overlay from the layer added last will be show. pub fn add_overlay(&mut self, layer: &'a [Overlay], highlight: Option<Highlight>) -> &mut Self { - if !layer.is_empty() { - self.overlays.push((layer, highlight).into()); - } + self.overlays.push((layer, highlight).into()); self } @@ -358,9 +219,8 @@ impl<'a> TextAnnotations<'a> { /// /// The line annotations **must be sorted** by their `char_idx`. /// Multiple line annotations with the same `char_idx` **are not allowed**. - pub fn add_line_annotation(&mut self, layer: Box<dyn LineAnnotation + 'a>) -> &mut Self { - self.line_annotations - .push((Cell::new(usize::MAX), layer.into())); + pub fn add_line_annotation(&mut self, layer: &'a [LineAnnotation]) -> &mut Self { + self.line_annotations.push((layer, ()).into()); self } @@ -390,35 +250,21 @@ impl<'a> TextAnnotations<'a> { overlay } - pub(crate) fn process_virtual_text_anchors(&self, grapheme: &FormattedGrapheme) { - for (next_anchor, layer) in &self.line_annotations { - loop { - match next_anchor.get().cmp(&grapheme.char_idx) { - Ordering::Less => next_anchor - .set(unsafe { layer.get().skip_concealed_anchors(grapheme.char_idx) }), - Ordering::Equal => { - next_anchor.set(unsafe { layer.get().process_anchor(grapheme) }) + pub(crate) fn annotation_lines_at(&self, char_idx: usize) -> usize { + self.line_annotations + .iter() + .map(|layer| { + let mut lines = 0; + while let Some(annot) = layer.annotations.get(layer.current_index.get()) { + if annot.anchor_char_idx == char_idx { + layer.current_index.set(layer.current_index.get() + 1); + lines += annot.height + } else { + break; } - Ordering::Greater => break, - }; - } - } - } - - pub(crate) fn virtual_lines_at( - &self, - char_idx: usize, - line_end_visual_pos: Position, - doc_line: usize, - ) -> usize { - let mut virt_off = Position::new(0, 0); - for (_, layer) in &self.line_annotations { - virt_off += unsafe { - layer - .get() - .insert_virtual_lines(char_idx, line_end_visual_pos + virt_off, doc_line) - }; - } - virt_off.row + } + lines + }) + .sum() } } |