Remove 2 suffix from gpui

Co-authored-by: Mikayla <mikayla@zed.dev>

crates/gpui/src/text_system/line_layout.rs

@@ -0,0 +1,414 @@
+use crate::{px, FontId, GlyphId, Pixels, PlatformTextSystem, Point, Size};
+use collections::FxHashMap;
+use parking_lot::{Mutex, RwLock, RwLockUpgradableReadGuard};
+use smallvec::SmallVec;
+use std::{
+    borrow::Borrow,
+    hash::{Hash, Hasher},
+    sync::Arc,
+};
+
+#[derive(Default, Debug)]
+pub struct LineLayout {
+    pub font_size: Pixels,
+    pub width: Pixels,
+    pub ascent: Pixels,
+    pub descent: Pixels,
+    pub runs: Vec<ShapedRun>,
+    pub len: usize,
+}
+
+#[derive(Debug)]
+pub struct ShapedRun {
+    pub font_id: FontId,
+    pub glyphs: SmallVec<[ShapedGlyph; 8]>,
+}
+
+#[derive(Clone, Debug)]
+pub struct ShapedGlyph {
+    pub id: GlyphId,
+    pub position: Point<Pixels>,
+    pub index: usize,
+    pub is_emoji: bool,
+}
+
+impl LineLayout {
+    pub fn index_for_x(&self, x: Pixels) -> Option<usize> {
+        if x >= self.width {
+            None
+        } else {
+            for run in self.runs.iter().rev() {
+                for glyph in run.glyphs.iter().rev() {
+                    if glyph.position.x <= x {
+                        return Some(glyph.index);
+                    }
+                }
+            }
+            Some(0)
+        }
+    }
+
+    /// closest_index_for_x returns the character boundary closest to the given x coordinate
+    /// (e.g. to handle aligning up/down arrow keys)
+    pub fn closest_index_for_x(&self, x: Pixels) -> usize {
+        let mut prev_index = 0;
+        let mut prev_x = px(0.);
+
+        for run in self.runs.iter() {
+            for glyph in run.glyphs.iter() {
+                if glyph.position.x >= x {
+                    if glyph.position.x - x < x - prev_x {
+                        return glyph.index;
+                    } else {
+                        return prev_index;
+                    }
+                }
+                prev_index = glyph.index;
+                prev_x = glyph.position.x;
+            }
+        }
+
+        self.len
+    }
+
+    pub fn x_for_index(&self, index: usize) -> Pixels {
+        for run in &self.runs {
+            for glyph in &run.glyphs {
+                if glyph.index >= index {
+                    return glyph.position.x;
+                }
+            }
+        }
+        self.width
+    }
+
+    fn compute_wrap_boundaries(
+        &self,
+        text: &str,
+        wrap_width: Pixels,
+    ) -> SmallVec<[WrapBoundary; 1]> {
+        let mut boundaries = SmallVec::new();
+
+        let mut first_non_whitespace_ix = None;
+        let mut last_candidate_ix = None;
+        let mut last_candidate_x = px(0.);
+        let mut last_boundary = WrapBoundary {
+            run_ix: 0,
+            glyph_ix: 0,
+        };
+        let mut last_boundary_x = px(0.);
+        let mut prev_ch = '\0';
+        let mut glyphs = self
+            .runs
+            .iter()
+            .enumerate()
+            .flat_map(move |(run_ix, run)| {
+                run.glyphs.iter().enumerate().map(move |(glyph_ix, glyph)| {
+                    let character = text[glyph.index..].chars().next().unwrap();
+                    (
+                        WrapBoundary { run_ix, glyph_ix },
+                        character,
+                        glyph.position.x,
+                    )
+                })
+            })
+            .peekable();
+
+        while let Some((boundary, ch, x)) = glyphs.next() {
+            if ch == '\n' {
+                continue;
+            }
+
+            if prev_ch == ' ' && ch != ' ' && first_non_whitespace_ix.is_some() {
+                last_candidate_ix = Some(boundary);
+                last_candidate_x = x;
+            }
+
+            if ch != ' ' && first_non_whitespace_ix.is_none() {
+                first_non_whitespace_ix = Some(boundary);
+            }
+
+            let next_x = glyphs.peek().map_or(self.width, |(_, _, x)| *x);
+            let width = next_x - last_boundary_x;
+            if width > wrap_width && boundary > last_boundary {
+                if let Some(last_candidate_ix) = last_candidate_ix.take() {
+                    last_boundary = last_candidate_ix;
+                    last_boundary_x = last_candidate_x;
+                } else {
+                    last_boundary = boundary;
+                    last_boundary_x = x;
+                }
+
+                boundaries.push(last_boundary);
+            }
+            prev_ch = ch;
+        }
+
+        boundaries
+    }
+}
+
+#[derive(Default, Debug)]
+pub struct WrappedLineLayout {
+    pub unwrapped_layout: Arc<LineLayout>,
+    pub wrap_boundaries: SmallVec<[WrapBoundary; 1]>,
+    pub wrap_width: Option<Pixels>,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct WrapBoundary {
+    pub run_ix: usize,
+    pub glyph_ix: usize,
+}
+
+impl WrappedLineLayout {
+    pub fn len(&self) -> usize {
+        self.unwrapped_layout.len
+    }
+
+    pub fn width(&self) -> Pixels {
+        self.wrap_width
+            .unwrap_or(Pixels::MAX)
+            .min(self.unwrapped_layout.width)
+    }
+
+    pub fn size(&self, line_height: Pixels) -> Size<Pixels> {
+        Size {
+            width: self.width(),
+            height: line_height * (self.wrap_boundaries.len() + 1),
+        }
+    }
+
+    pub fn ascent(&self) -> Pixels {
+        self.unwrapped_layout.ascent
+    }
+
+    pub fn descent(&self) -> Pixels {
+        self.unwrapped_layout.descent
+    }
+
+    pub fn wrap_boundaries(&self) -> &[WrapBoundary] {
+        &self.wrap_boundaries
+    }
+
+    pub fn font_size(&self) -> Pixels {
+        self.unwrapped_layout.font_size
+    }
+
+    pub fn runs(&self) -> &[ShapedRun] {
+        &self.unwrapped_layout.runs
+    }
+
+    pub fn index_for_position(
+        &self,
+        position: Point<Pixels>,
+        line_height: Pixels,
+    ) -> Option<usize> {
+        let wrapped_line_ix = (position.y / line_height) as usize;
+
+        let wrapped_line_start_x = if wrapped_line_ix > 0 {
+            let wrap_boundary_ix = wrapped_line_ix - 1;
+            let wrap_boundary = self.wrap_boundaries[wrap_boundary_ix];
+            let run = &self.unwrapped_layout.runs[wrap_boundary.run_ix];
+            run.glyphs[wrap_boundary.glyph_ix].position.x
+        } else {
+            Pixels::ZERO
+        };
+
+        let wrapped_line_end_x = if wrapped_line_ix < self.wrap_boundaries.len() {
+            let next_wrap_boundary_ix = wrapped_line_ix;
+            let next_wrap_boundary = self.wrap_boundaries[next_wrap_boundary_ix];
+            let run = &self.unwrapped_layout.runs[next_wrap_boundary.run_ix];
+            run.glyphs[next_wrap_boundary.glyph_ix].position.x
+        } else {
+            self.unwrapped_layout.width
+        };
+
+        let mut position_in_unwrapped_line = position;
+        position_in_unwrapped_line.x += wrapped_line_start_x;
+        if position_in_unwrapped_line.x > wrapped_line_end_x {
+            None
+        } else {
+            self.unwrapped_layout
+                .index_for_x(position_in_unwrapped_line.x)
+        }
+    }
+}
+
+pub(crate) struct LineLayoutCache {
+    previous_frame: Mutex<FxHashMap<CacheKey, Arc<LineLayout>>>,
+    current_frame: RwLock<FxHashMap<CacheKey, Arc<LineLayout>>>,
+    previous_frame_wrapped: Mutex<FxHashMap<CacheKey, Arc<WrappedLineLayout>>>,
+    current_frame_wrapped: RwLock<FxHashMap<CacheKey, Arc<WrappedLineLayout>>>,
+    platform_text_system: Arc<dyn PlatformTextSystem>,
+}
+
+impl LineLayoutCache {
+    pub fn new(platform_text_system: Arc<dyn PlatformTextSystem>) -> Self {
+        Self {
+            previous_frame: Mutex::default(),
+            current_frame: RwLock::default(),
+            previous_frame_wrapped: Mutex::default(),
+            current_frame_wrapped: RwLock::default(),
+            platform_text_system,
+        }
+    }
+
+    pub fn start_frame(&self) {
+        let mut prev_frame = self.previous_frame.lock();
+        let mut curr_frame = self.current_frame.write();
+        std::mem::swap(&mut *prev_frame, &mut *curr_frame);
+        curr_frame.clear();
+    }
+
+    pub fn layout_wrapped_line(
+        &self,
+        text: &str,
+        font_size: Pixels,
+        runs: &[FontRun],
+        wrap_width: Option<Pixels>,
+    ) -> Arc<WrappedLineLayout> {
+        let key = &CacheKeyRef {
+            text,
+            font_size,
+            runs,
+            wrap_width,
+        } as &dyn AsCacheKeyRef;
+
+        let current_frame = self.current_frame_wrapped.upgradable_read();
+        if let Some(layout) = current_frame.get(key) {
+            return layout.clone();
+        }
+
+        let mut current_frame = RwLockUpgradableReadGuard::upgrade(current_frame);
+        if let Some((key, layout)) = self.previous_frame_wrapped.lock().remove_entry(key) {
+            current_frame.insert(key, layout.clone());
+            layout
+        } else {
+            let unwrapped_layout = self.layout_line(text, font_size, runs);
+            let wrap_boundaries = if let Some(wrap_width) = wrap_width {
+                unwrapped_layout.compute_wrap_boundaries(text.as_ref(), wrap_width)
+            } else {
+                SmallVec::new()
+            };
+            let layout = Arc::new(WrappedLineLayout {
+                unwrapped_layout,
+                wrap_boundaries,
+                wrap_width,
+            });
+            let key = CacheKey {
+                text: text.into(),
+                font_size,
+                runs: SmallVec::from(runs),
+                wrap_width,
+            };
+            current_frame.insert(key, layout.clone());
+            layout
+        }
+    }
+
+    pub fn layout_line(&self, text: &str, font_size: Pixels, runs: &[FontRun]) -> Arc<LineLayout> {
+        let key = &CacheKeyRef {
+            text,
+            font_size,
+            runs,
+            wrap_width: None,
+        } as &dyn AsCacheKeyRef;
+
+        let current_frame = self.current_frame.upgradable_read();
+        if let Some(layout) = current_frame.get(key) {
+            return layout.clone();
+        }
+
+        let mut current_frame = RwLockUpgradableReadGuard::upgrade(current_frame);
+        if let Some((key, layout)) = self.previous_frame.lock().remove_entry(key) {
+            current_frame.insert(key, layout.clone());
+            layout
+        } else {
+            let layout = Arc::new(self.platform_text_system.layout_line(text, font_size, runs));
+            let key = CacheKey {
+                text: text.into(),
+                font_size,
+                runs: SmallVec::from(runs),
+                wrap_width: None,
+            };
+            current_frame.insert(key, layout.clone());
+            layout
+        }
+    }
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct FontRun {
+    pub(crate) len: usize,
+    pub(crate) font_id: FontId,
+}
+
+trait AsCacheKeyRef {
+    fn as_cache_key_ref(&self) -> CacheKeyRef;
+}
+
+#[derive(Eq)]
+struct CacheKey {
+    text: String,
+    font_size: Pixels,
+    runs: SmallVec<[FontRun; 1]>,
+    wrap_width: Option<Pixels>,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+struct CacheKeyRef<'a> {
+    text: &'a str,
+    font_size: Pixels,
+    runs: &'a [FontRun],
+    wrap_width: Option<Pixels>,
+}
+
+impl<'a> PartialEq for (dyn AsCacheKeyRef + 'a) {
+    fn eq(&self, other: &dyn AsCacheKeyRef) -> bool {
+        self.as_cache_key_ref() == other.as_cache_key_ref()
+    }
+}
+
+impl<'a> Eq for (dyn AsCacheKeyRef + 'a) {}
+
+impl<'a> Hash for (dyn AsCacheKeyRef + 'a) {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.as_cache_key_ref().hash(state)
+    }
+}
+
+impl AsCacheKeyRef for CacheKey {
+    fn as_cache_key_ref(&self) -> CacheKeyRef {
+        CacheKeyRef {
+            text: &self.text,
+            font_size: self.font_size,
+            runs: self.runs.as_slice(),
+            wrap_width: self.wrap_width,
+        }
+    }
+}
+
+impl PartialEq for CacheKey {
+    fn eq(&self, other: &Self) -> bool {
+        self.as_cache_key_ref().eq(&other.as_cache_key_ref())
+    }
+}
+
+impl Hash for CacheKey {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.as_cache_key_ref().hash(state);
+    }
+}
+
+impl<'a> Borrow<dyn AsCacheKeyRef + 'a> for CacheKey {
+    fn borrow(&self) -> &(dyn AsCacheKeyRef + 'a) {
+        self as &dyn AsCacheKeyRef
+    }
+}
+
+impl<'a> AsCacheKeyRef for CacheKeyRef<'a> {
+    fn as_cache_key_ref(&self) -> CacheKeyRef {
+        *self
+    }
+}