Move and refactor

4 files changed, 258 insertions, 250 deletions

diff --git a/src/layout/incremental.rs b/src/layout/incremental.rs
index ca4839b6..e4496f06 100644
--- a/src/layout/incremental.rs
+++ b/src/layout/incremental.rs
@@ -5,14 +5,16 @@ use std::ops::Deref;
 use super::*;
 
 /// Caches layouting artifacts.
-#[derive(Default, Debug, Clone)]
+///
+/// _This is only available when the `layout-cache` feature is enabled._
 #[cfg(feature = "layout-cache")]
+#[derive(Default, Debug, Clone)]
 pub struct LayoutCache {
     /// Maps from node hashes to the resulting frames and regions in which the
     /// frames are valid. The right hand side of the hash map is a vector of
     /// results because across one or more compilations, multiple different
     /// layouts of the same node may have been requested.
-    pub frames: HashMap<u64, Vec<FramesEntry>>,
+    frames: HashMap<u64, Vec<FramesEntry>>,
     /// In how many compilations this cache has been used.
     age: usize,
 }
@@ -24,67 +26,42 @@ impl LayoutCache {
         Self::default()
     }
 
-    /// Clear the cache.
-    pub fn clear(&mut self) {
-        self.frames.clear();
+    /// Whether the cache is empty.
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
     }
 
     /// Amount of items in the cache.
     pub fn len(&self) -> usize {
-        self.frames.iter().map(|(_, e)| e.len()).sum()
-    }
-
-    /// Retains all elements for which the closure on the level returns `true`.
-    pub fn retain<F>(&mut self, mut f: F)
-    where
-        F: FnMut(usize) -> bool,
-    {
-        for (_, entries) in self.frames.iter_mut() {
-            entries.retain(|entry| f(entry.level));
-        }
+        self.frames.values().map(Vec::len).sum()
     }
 
-    /// Prepare the cache for the next round of compilation
-    pub fn turnaround(&mut self) {
-        self.age += 1;
-        for entry in self.frames.iter_mut().flat_map(|(_, x)| x.iter_mut()) {
-            for i in 0 .. (entry.temperature.len() - 1) {
-                entry.temperature[i + 1] = entry.temperature[i];
-            }
-            entry.temperature[0] = 0;
-            entry.age += 1;
-        }
+    /// The number of levels stored in the cache.
+    pub fn levels(&self) -> usize {
+        self.entries().map(|entry| entry.level + 1).max().unwrap_or(0)
     }
 
-    /// The amount of levels stored in the cache.
-    pub fn levels(&self) -> usize {
-        self.frames
-            .iter()
-            .flat_map(|(_, x)| x)
-            .map(|entry| entry.level + 1)
-            .max()
-            .unwrap_or(0)
+    /// An iterator over all entries in the cache.
+    pub fn entries(&self) -> impl Iterator<Item = &FramesEntry> + '_ {
+        self.frames.values().flatten()
     }
 
-    /// Fetches the appropriate entry from the cache if there is any.
+    /// Fetch matching cached frames if there are any.
     pub fn get(
         &mut self,
         hash: u64,
         regions: Regions,
     ) -> Option<Vec<Constrained<Rc<Frame>>>> {
-        self.frames.get_mut(&hash).and_then(|frames| {
-            for frame in frames {
-                let res = frame.check(regions.clone());
-                if res.is_some() {
-                    return res;
-                }
+        let entries = self.frames.get_mut(&hash)?;
+        for entry in entries {
+            if let Some(frames) = entry.check(regions.clone()) {
+                return Some(frames);
             }
-
-            None
-        })
+        }
+        None
     }
 
-    /// Inserts a new frame set into the cache.
+    /// Insert a new frame entry into the cache.
     pub fn insert(
         &mut self,
         hash: u64,
@@ -99,16 +76,45 @@ impl LayoutCache {
             }
         }
     }
+
+    /// Clear the cache.
+    pub fn clear(&mut self) {
+        self.frames.clear();
+    }
+
+    /// Retain all elements for which the closure on the level returns `true`.
+    pub fn retain<F>(&mut self, mut f: F)
+    where
+        F: FnMut(usize) -> bool,
+    {
+        for entries in self.frames.values_mut() {
+            entries.retain(|entry| f(entry.level));
+        }
+    }
+
+    /// Prepare the cache for the next round of compilation.
+    pub fn turnaround(&mut self) {
+        self.age += 1;
+        for entry in self.frames.values_mut().flatten() {
+            for i in 0 .. (entry.temperature.len() - 1) {
+                entry.temperature[i + 1] = entry.temperature[i];
+            }
+            entry.temperature[0] = 0;
+            entry.age += 1;
+        }
+    }
 }
 
 /// Cached frames from past layouting.
-#[derive(Debug, Clone)]
+///
+/// _This is only available when the `layout-cache` feature is enabled._
 #[cfg(feature = "layout-cache")]
+#[derive(Debug, Clone)]
 pub struct FramesEntry {
     /// The cached frames for a node.
-    pub frames: Vec<Constrained<Rc<Frame>>>,
+    frames: Vec<Constrained<Rc<Frame>>>,
     /// How nested the frame was in the context is was originally appearing in.
-    pub level: usize,
+    level: usize,
     /// For how long the element already exists.
     age: usize,
     /// How much the element was accessed during the last five compilations, the
@@ -128,7 +134,8 @@ impl FramesEntry {
         }
     }
 
-    /// Checks if the cached [`Frame`] is valid for the given regions.
+    /// Checks if the cached frames are valid in the given regions and returns
+    /// them if so.
     pub fn check(&mut self, mut regions: Regions) -> Option<Vec<Constrained<Rc<Frame>>>> {
         for (i, frame) in self.frames.iter().enumerate() {
             if (i != 0 && !regions.next()) || !frame.constraints.check(&regions) {
@@ -137,18 +144,25 @@ impl FramesEntry {
         }
 
         self.temperature[0] += 1;
-
         Some(self.frames.clone())
     }
 
-    /// Get the amount of compilation cycles this item has remained in the
-    /// cache.
+    /// How nested the frame was in the context is was originally appearing in.
+    pub fn level(&self) -> usize {
+        self.level
+    }
+
+    /// The number of compilation cycles this item has remained in the cache.
     pub fn age(&self) -> usize {
         self.age
     }
 
-    /// Get the amount of consecutive cycles in which this item has not
-    /// been used.
+    /// Whether this element was used in the last compilation cycle.
+    pub fn hit(&self) -> bool {
+        self.temperature[0] != 0
+    }
+
+    /// The amount of consecutive cycles in which this item has not been used.
     pub fn cooldown(&self) -> usize {
         let mut cycle = 0;
         for &temp in &self.temperature[.. self.age] {
@@ -157,13 +171,23 @@ impl FramesEntry {
             }
             cycle += 1;
         }
-
         cycle
     }
+}
 
-    /// Whether this element was used in the last compilation cycle.
-    pub fn hit(&self) -> bool {
-        self.temperature[0] != 0
+/// Carries an item that only applies to certain regions and the constraints
+/// that describe these regions.
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub struct Constrained<T> {
+    pub item: T,
+    pub constraints: Constraints,
+}
+
+impl<T> Deref for Constrained<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.item
     }
 }
 
@@ -194,6 +218,21 @@ impl Constraints {
         }
     }
 
+    #[cfg(feature = "layout-cache")]
+    fn check(&self, regions: &Regions) -> bool {
+        if self.expand != regions.expand {
+            return false;
+        }
+
+        let base = regions.base.to_spec();
+        let current = regions.current.to_spec();
+
+        current.eq_by(&self.min, |x, y| y.map_or(true, |y| x.fits(y)))
+            && current.eq_by(&self.max, |x, y| y.map_or(true, |y| x < &y))
+            && current.eq_by(&self.exact, |x, y| y.map_or(true, |y| x.approx_eq(y)))
+            && base.eq_by(&self.base, |x, y| y.map_or(true, |y| x.approx_eq(y)))
+    }
+
     /// Set the appropriate base constraints for (relative) width and height
     /// metrics, respectively.
     pub fn set_base_using_linears(
@@ -210,21 +249,6 @@ impl Constraints {
         }
     }
 
-    #[cfg(feature = "layout-cache")]
-    fn check(&self, regions: &Regions) -> bool {
-        if self.expand != regions.expand {
-            return false;
-        }
-
-        let base = regions.base.to_spec();
-        let current = regions.current.to_spec();
-
-        current.eq_by(&self.min, |x, y| y.map_or(true, |y| x.fits(y)))
-            && current.eq_by(&self.max, |x, y| y.map_or(true, |y| x < &y))
-            && current.eq_by(&self.exact, |x, y| y.map_or(true, |y| x.approx_eq(y)))
-            && base.eq_by(&self.base, |x, y| y.map_or(true, |y| x.approx_eq(y)))
-    }
-
     /// Changes all constraints by adding the `size` to them if they are `Some`.
     pub fn mutate(&mut self, size: Size, regions: &Regions) {
         for spec in [
@@ -251,22 +275,6 @@ impl Constraints {
     }
 }
 
-/// Carries an item that only applies to certain regions and the constraints
-/// that describe these regions.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-pub struct Constrained<T> {
-    pub item: T,
-    pub constraints: Constraints,
-}
-
-impl<T> Deref for Constrained<T> {
-    type Target = T;
-
-    fn deref(&self) -> &Self::Target {
-        &self.item
-    }
-}
-
 /// Extends length-related options by providing convenience methods for setting
 /// minimum and maximum lengths on them, even if they are `None`.
 pub trait OptionExt {
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index 7f8ee4ff..22e6e8c8 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -10,6 +10,7 @@ mod pad;
 mod par;
 mod shaping;
 mod stack;
+mod tree;
 
 pub use self::image::*;
 pub use background::*;
@@ -21,21 +22,16 @@ pub use pad::*;
 pub use par::*;
 pub use shaping::*;
 pub use stack::*;
+pub use tree::*;
 
-use std::any::Any;
-use std::fmt::{self, Debug, Formatter};
 use std::hash::Hash;
 #[cfg(feature = "layout-cache")]
 use std::hash::Hasher;
 use std::rc::Rc;
 
-#[cfg(feature = "layout-cache")]
-use fxhash::FxHasher64;
-
 use crate::font::FontCache;
 use crate::geom::*;
 use crate::image::ImageCache;
-use crate::loading::Loader;
 use crate::Context;
 
 /// Layout a tree into a collection of frames.
@@ -44,157 +40,6 @@ pub fn layout(ctx: &mut Context, tree: &LayoutTree) -> Vec<Rc<Frame>> {
     tree.layout(&mut ctx)
 }
 
-/// A tree of layout nodes.
-#[derive(Debug, Clone, Eq, PartialEq)]
-pub struct LayoutTree {
-    /// Runs of pages with the same properties.
-    pub runs: Vec<PageRun>,
-}
-
-impl LayoutTree {
-    /// Layout the tree into a collection of frames.
-    pub fn layout(&self, ctx: &mut LayoutContext) -> Vec<Rc<Frame>> {
-        self.runs.iter().flat_map(|run| run.layout(ctx)).collect()
-    }
-}
-
-/// A run of pages that all have the same properties.
-#[derive(Debug, Clone, Eq, PartialEq)]
-pub struct PageRun {
-    /// The size of each page.
-    pub size: Size,
-    /// The layout node that produces the actual pages (typically a
-    /// [`StackNode`]).
-    pub child: LayoutNode,
-}
-
-impl PageRun {
-    /// Layout the page run.
-    pub fn layout(&self, ctx: &mut LayoutContext) -> Vec<Rc<Frame>> {
-        // When one of the lengths is infinite the page fits its content along
-        // that axis.
-        let Size { width, height } = self.size;
-        let expand = Spec::new(width.is_finite(), height.is_finite());
-        let regions = Regions::repeat(self.size, expand);
-        self.child.layout(ctx, &regions).into_iter().map(|c| c.item).collect()
-    }
-}
-
-/// A dynamic layouting node.
-pub struct LayoutNode {
-    node: Box<dyn Bounds>,
-    #[cfg(feature = "layout-cache")]
-    hash: u64,
-}
-
-impl LayoutNode {
-    /// Create a new instance from any node that satisifies the required bounds.
-    #[cfg(feature = "layout-cache")]
-    pub fn new<T>(node: T) -> Self
-    where
-        T: Layout + Debug + Clone + Eq + PartialEq + Hash + 'static,
-    {
-        let hash = {
-            let mut state = FxHasher64::default();
-            node.type_id().hash(&mut state);
-            node.hash(&mut state);
-            state.finish()
-        };
-
-        Self { node: Box::new(node), hash }
-    }
-
-    /// Create a new instance from any node that satisifies the required bounds.
-    #[cfg(not(feature = "layout-cache"))]
-    pub fn new<T>(node: T) -> Self
-    where
-        T: Layout + Debug + Clone + Eq + PartialEq + 'static,
-    {
-        Self { node: Box::new(node) }
-    }
-}
-
-impl Layout for LayoutNode {
-    fn layout(
-        &self,
-        ctx: &mut LayoutContext,
-        regions: &Regions,
-    ) -> Vec<Constrained<Rc<Frame>>> {
-        #[cfg(feature = "layout-cache")]
-        {
-            ctx.level += 1;
-            let frames = ctx.layouts.get(self.hash, regions.clone()).unwrap_or_else(|| {
-                let frames = self.node.layout(ctx, regions);
-                ctx.layouts.insert(self.hash, frames.clone(), ctx.level - 1);
-                frames
-            });
-            ctx.level -= 1;
-            frames
-        }
-
-        #[cfg(not(feature = "layout-cache"))]
-        self.node.layout(ctx, regions)
-    }
-}
-
-impl Debug for LayoutNode {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        self.node.fmt(f)
-    }
-}
-
-impl Clone for LayoutNode {
-    fn clone(&self) -> Self {
-        Self {
-            node: self.node.dyn_clone(),
-            #[cfg(feature = "layout-cache")]
-            hash: self.hash,
-        }
-    }
-}
-
-impl Eq for LayoutNode {}
-
-impl PartialEq for LayoutNode {
-    fn eq(&self, other: &Self) -> bool {
-        self.node.dyn_eq(other.node.as_ref())
-    }
-}
-
-#[cfg(feature = "layout-cache")]
-impl Hash for LayoutNode {
-    fn hash<H: Hasher>(&self, state: &mut H) {
-        state.write_u64(self.hash);
-    }
-}
-
-trait Bounds: Layout + Debug + 'static {
-    fn as_any(&self) -> &dyn Any;
-    fn dyn_eq(&self, other: &dyn Bounds) -> bool;
-    fn dyn_clone(&self) -> Box<dyn Bounds>;
-}
-
-impl<T> Bounds for T
-where
-    T: Layout + Debug + Eq + PartialEq + Clone + 'static,
-{
-    fn as_any(&self) -> &dyn Any {
-        self
-    }
-
-    fn dyn_eq(&self, other: &dyn Bounds) -> bool {
-        if let Some(other) = other.as_any().downcast_ref::<Self>() {
-            self == other
-        } else {
-            false
-        }
-    }
-
-    fn dyn_clone(&self) -> Box<dyn Bounds> {
-        Box::new(self.clone())
-    }
-}
-
 /// Layout a node.
 pub trait Layout {
     /// Layout the node into the given regions.
@@ -207,8 +52,6 @@ pub trait Layout {
 
 /// The context for layouting.
 pub struct LayoutContext<'a> {
-    /// The loader from which fonts are loaded.
-    pub loader: &'a dyn Loader,
     /// The cache for parsed font faces.
     pub fonts: &'a mut FontCache,
     /// The cache for decoded imges.
@@ -225,7 +68,6 @@ impl<'a> LayoutContext<'a> {
     /// Create a new layout context.
     pub fn new(ctx: &'a mut Context) -> Self {
         Self {
-            loader: ctx.loader.as_ref(),
             fonts: &mut ctx.fonts,
             images: &mut ctx.images,
             #[cfg(feature = "layout-cache")]
diff --git a/src/layout/par.rs b/src/layout/par.rs
index 72b3edfb..8736452b 100644
--- a/src/layout/par.rs
+++ b/src/layout/par.rs
@@ -47,7 +47,7 @@ impl Layout for ParNode {
         // Find out the BiDi embedding levels.
         let bidi = BidiInfo::new(&text, Level::from_dir(self.dir));
 
-        // Prepare paragraph layout by bulding a representation on which we can
+        // Prepare paragraph layout by building a representation on which we can
         // do line breaking without layouting each and every line from scratch.
         let layouter = ParLayouter::new(self, ctx, regions, bidi);
 
diff --git a/src/layout/tree.rs b/src/layout/tree.rs
new file mode 100644
index 00000000..258f1ccc
--- /dev/null
+++ b/src/layout/tree.rs
@@ -0,0 +1,158 @@
+use super::*;
+
+use std::any::Any;
+use std::fmt::{self, Debug, Formatter};
+
+#[cfg(feature = "layout-cache")]
+use fxhash::FxHasher64;
+
+/// A tree of layout nodes.
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct LayoutTree {
+    /// Runs of pages with the same properties.
+    pub runs: Vec<PageRun>,
+}
+
+impl LayoutTree {
+    /// Layout the tree into a collection of frames.
+    pub fn layout(&self, ctx: &mut LayoutContext) -> Vec<Rc<Frame>> {
+        self.runs.iter().flat_map(|run| run.layout(ctx)).collect()
+    }
+}
+
+/// A run of pages that all have the same properties.
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct PageRun {
+    /// The size of each page.
+    pub size: Size,
+    /// The layout node that produces the actual pages (typically a
+    /// [`StackNode`]).
+    pub child: LayoutNode,
+}
+
+impl PageRun {
+    /// Layout the page run.
+    pub fn layout(&self, ctx: &mut LayoutContext) -> Vec<Rc<Frame>> {
+        // When one of the lengths is infinite the page fits its content along
+        // that axis.
+        let Size { width, height } = self.size;
+        let expand = Spec::new(width.is_finite(), height.is_finite());
+        let regions = Regions::repeat(self.size, expand);
+        self.child.layout(ctx, &regions).into_iter().map(|c| c.item).collect()
+    }
+}
+
+/// A dynamic layouting node.
+pub struct LayoutNode {
+    node: Box<dyn Bounds>,
+    #[cfg(feature = "layout-cache")]
+    hash: u64,
+}
+
+impl LayoutNode {
+    /// Create a new instance from any node that satisifies the required bounds.
+    #[cfg(feature = "layout-cache")]
+    pub fn new<T>(node: T) -> Self
+    where
+        T: Layout + Debug + Clone + Eq + PartialEq + Hash + 'static,
+    {
+        let hash = {
+            let mut state = FxHasher64::default();
+            node.type_id().hash(&mut state);
+            node.hash(&mut state);
+            state.finish()
+        };
+
+        Self { node: Box::new(node), hash }
+    }
+
+    /// Create a new instance from any node that satisifies the required bounds.
+    #[cfg(not(feature = "layout-cache"))]
+    pub fn new<T>(node: T) -> Self
+    where
+        T: Layout + Debug + Clone + Eq + PartialEq + 'static,
+    {
+        Self { node: Box::new(node) }
+    }
+}
+
+impl Layout for LayoutNode {
+    fn layout(
+        &self,
+        ctx: &mut LayoutContext,
+        regions: &Regions,
+    ) -> Vec<Constrained<Rc<Frame>>> {
+        #[cfg(feature = "layout-cache")]
+        {
+            ctx.level += 1;
+            let frames = ctx.layouts.get(self.hash, regions.clone()).unwrap_or_else(|| {
+                let frames = self.node.layout(ctx, regions);
+                ctx.layouts.insert(self.hash, frames.clone(), ctx.level - 1);
+                frames
+            });
+            ctx.level -= 1;
+            frames
+        }
+
+        #[cfg(not(feature = "layout-cache"))]
+        self.node.layout(ctx, regions)
+    }
+}
+
+impl Debug for LayoutNode {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        self.node.fmt(f)
+    }
+}
+
+impl Clone for LayoutNode {
+    fn clone(&self) -> Self {
+        Self {
+            node: self.node.dyn_clone(),
+            #[cfg(feature = "layout-cache")]
+            hash: self.hash,
+        }
+    }
+}
+
+impl Eq for LayoutNode {}
+
+impl PartialEq for LayoutNode {
+    fn eq(&self, other: &Self) -> bool {
+        self.node.dyn_eq(other.node.as_ref())
+    }
+}
+
+#[cfg(feature = "layout-cache")]
+impl Hash for LayoutNode {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        state.write_u64(self.hash);
+    }
+}
+
+trait Bounds: Layout + Debug + 'static {
+    fn as_any(&self) -> &dyn Any;
+    fn dyn_eq(&self, other: &dyn Bounds) -> bool;
+    fn dyn_clone(&self) -> Box<dyn Bounds>;
+}
+
+impl<T> Bounds for T
+where
+    T: Layout + Debug + Eq + PartialEq + Clone + 'static,
+{
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn dyn_eq(&self, other: &dyn Bounds) -> bool {
+        if let Some(other) = other.as_any().downcast_ref::<Self>() {
+            self == other
+        } else {
+            false
+        }
+    }
+
+    fn dyn_clone(&self) -> Box<dyn Bounds> {
+        Box::new(self.clone())
+    }
+}