CoreText: Faster OTC font loading

src/handle.rs

@@ -14,11 +14,13 @@
 //!
 //! To open the font referenced by a handle, use a loader.
 
+use std::any::Any;
 use std::path::PathBuf;
 use std::sync::Arc;
 
 use crate::error::FontLoadingError;
 use crate::font::Font;
+use crate::loader::Loader;
 
 /// Encapsulates the information needed to locate and open a font.
 ///
@@ -45,6 +47,11 @@ pub enum Handle {
         /// If the memory consists of a single font, this value will be 0.
         font_index: u32,
     },
+    /// An already-loaded font.
+    Native {
+        /// Type-erased font storage. Use [`Self::as_native`] to retrieve the font object.
+        inner: Arc<dyn Any + Sync + Send>,
+    },
 }
 
 impl Handle {
@@ -66,6 +73,25 @@ impl Handle {
         Handle::Memory { bytes, font_index }
     }
 
+    /// Creates a new handle from a system handle.
+    pub fn from_native<T: Loader>(inner: &T) -> Self
+    where
+        T::NativeFont: Sync + Send,
+    {
+        Self::Native {
+            inner: Arc::new(inner.native_font()),
+        }
+    }
+    /// Retrieves a handle to the font object.
+    ///
+    /// May return None if inner object is not of type `T` or if this handle does not contain a native font object.
+    pub fn as_native<T: 'static>(&self) -> Option<&T> {
+        if let Self::Native { inner } = self {
+            inner.downcast_ref()
+        } else {
+            None
+        }
+    }
     /// A convenience method to load this handle with the default loader, producing a Font.
     #[inline]
     pub fn load(&self) -> Result<Font, FontLoadingError> {

src/loader.rs

@@ -35,7 +35,7 @@ use std::path::Path;
 /// fonts.
 pub trait Loader: Clone + Sized {
     /// The handle that the API natively uses to represent a font.
-    type NativeFont;
+    type NativeFont: 'static;
 
     /// Loads a font from raw font data (the contents of a `.ttf`/`.otf`/etc. file).
     ///
@@ -63,22 +63,26 @@ pub trait Loader: Clone + Sized {
     }
 
     /// Creates a font from a native API handle.
-    unsafe fn from_native_font(native_font: Self::NativeFont) -> Self;
+    unsafe fn from_native_font(native_font: &Self::NativeFont) -> Self;
 
     /// Loads the font pointed to by a handle.
     fn from_handle(handle: &Handle) -> Result<Self, FontLoadingError> {
-        match *handle {
-            Handle::Memory {
-                ref bytes,
-                font_index,
-            } => Self::from_bytes((*bytes).clone(), font_index),
+        match handle {
+            Handle::Memory { bytes, font_index } => Self::from_bytes((*bytes).clone(), *font_index),
             #[cfg(not(target_arch = "wasm32"))]
             Handle::Path {
                 ref path,
                 font_index,
-            } => Self::from_path(path, font_index),
+            } => Self::from_path(path, *font_index),
             #[cfg(target_arch = "wasm32")]
             Handle::Path { .. } => Err(FontLoadingError::NoFilesystem),
+            Handle::Native { .. } => {
+                if let Some(native) = handle.as_native::<Self::NativeFont>() {
+                    unsafe { Ok(Self::from_native_font(native)) }
+                } else {
+                    Err(FontLoadingError::UnknownFormat)
+                }
+            }
         }
     }
 

src/loaders/core_text.rs

@@ -122,29 +122,14 @@ impl Font {
     }
 
     /// Creates a font from a native API handle.
-    pub unsafe fn from_native_font(core_text_font: NativeFont) -> Font {
-        Font::from_core_text_font(core_text_font)
-    }
-
-    unsafe fn from_core_text_font(core_text_font: NativeFont) -> Font {
-        let mut font_data = FontData::Unavailable;
-        match core_text_font.url() {
-            None => warn!("No URL found for Core Text font!"),
-            Some(url) => match url.to_path() {
-                Some(path) => match File::open(path) {
-                    Ok(ref mut file) => match utils::slurp_file(file) {
-                        Ok(data) => font_data = FontData::Memory(Arc::new(data)),
-                        Err(_) => warn!("Couldn't read file data for Core Text font!"),
-                    },
-                    Err(_) => warn!("Could not open file for Core Text font!"),
-                },
-                None => warn!("Could not convert URL from Core Text font to path!"),
-            },
-        }
-
+    pub unsafe fn from_native_font(core_text_font: &NativeFont) -> Font {
+        Font::from_core_text_font_no_path(core_text_font.clone())
+    }
+    /// Creates a font from a native API handle, without performing a lookup on the disk.
+    pub unsafe fn from_core_text_font_no_path(core_text_font: NativeFont) -> Font {
         Font {
             core_text_font,
-            font_data,
+            font_data: FontData::Unavailable,
         }
     }
 
@@ -153,7 +138,10 @@ impl Font {
     /// This function is only available on the Core Text backend.
     pub fn from_core_graphics_font(core_graphics_font: CGFont) -> Font {
         unsafe {
-            Font::from_core_text_font(core_text::font::new_from_CGFont(&core_graphics_font, 16.0))
+            Font::from_core_text_font_no_path(core_text::font::new_from_CGFont(
+                &core_graphics_font,
+                16.0,
+            ))
         }
     }
 
@@ -628,7 +616,7 @@ impl Loader for Font {
     }
 
     #[inline]
-    unsafe fn from_native_font(native_font: Self::NativeFont) -> Self {
+    unsafe fn from_native_font(native_font: &Self::NativeFont) -> Self {
         Font::from_native_font(native_font)
     }
 

src/loaders/directwrite.rs

@@ -61,6 +61,7 @@ const OPENTYPE_TABLE_TAG_HEAD: u32 = 0x68656164;
 
 /// DirectWrite's representation of a font.
 #[allow(missing_debug_implementations)]
+#[derive(Clone)]
 pub struct NativeFont {
     /// The native DirectWrite font object.
     pub dwrite_font: DWriteFont,
@@ -160,7 +161,8 @@ impl Font {
 
     /// Creates a font from a native API handle.
     #[inline]
-    pub unsafe fn from_native_font(native_font: NativeFont) -> Font {
+    pub unsafe fn from_native_font(native_font: &NativeFont) -> Font {
+        let native_font = native_font.clone();
         Font {
             dwrite_font: native_font.dwrite_font,
             dwrite_font_face: native_font.dwrite_font_face,
@@ -747,7 +749,7 @@ impl Loader for Font {
     }
 
     #[inline]
-    unsafe fn from_native_font(native_font: Self::NativeFont) -> Self {
+    unsafe fn from_native_font(native_font: &Self::NativeFont) -> Self {
         Font::from_native_font(native_font)
     }
 

src/loaders/freetype.rs

@@ -197,9 +197,10 @@ impl Font {
     }
 
     /// Creates a font from a native API handle.
-    pub unsafe fn from_native_font(freetype_face: NativeFont) -> Font {
+    pub unsafe fn from_native_font(freetype_face: &NativeFont) -> Font {
         // We make an in-memory copy of the underlying font data. This is because the native font
         // does not necessarily hold a strong reference to the memory backing it.
+        let freetype_face = *freetype_face;
         const CHUNK_SIZE: usize = 4096;
         let mut font_data = vec![];
         loop {
@@ -1036,7 +1037,7 @@ impl Loader for Font {
     }
 
     #[inline]
-    unsafe fn from_native_font(native_font: Self::NativeFont) -> Self {
+    unsafe fn from_native_font(native_font: &Self::NativeFont) -> Self {
         Font::from_native_font(native_font)
     }
 

src/sources/core_text.rs

@@ -14,6 +14,7 @@ use core_foundation::array::CFArray;
 use core_foundation::base::{CFType, TCFType};
 use core_foundation::dictionary::CFDictionary;
 use core_foundation::string::CFString;
+use core_text::font::new_from_descriptor;
 use core_text::font_collection::{self, CTFontCollection};
 use core_text::font_descriptor::{self, CTFontDescriptor};
 use core_text::font_manager;
@@ -153,68 +154,17 @@ fn css_stretchiness_to_core_text_width(css_stretchiness: Stretch) -> f32 {
     0.25 * core_text_loader::piecewise_linear_find_index(css_stretchiness, &Stretch::MAPPING) - 1.0
 }
 
-#[derive(Clone)]
-struct FontDataInfo {
-    data: Arc<Vec<u8>>,
-    file_type: FileType,
-}
-
 fn create_handles_from_core_text_collection(
     collection: CTFontCollection,
 ) -> Result<Vec<Handle>, SelectionError> {
     let mut fonts = vec![];
     if let Some(descriptors) = collection.get_descriptors() {
-        let mut font_data_info_cache: HashMap<PathBuf, FontDataInfo> = HashMap::new();
-
-        'outer: for index in 0..descriptors.len() {
+        for index in 0..descriptors.len() {
             let descriptor = descriptors.get(index).unwrap();
-            let font_path = descriptor.font_path().unwrap();
-
-            let data_info = if let Some(data_info) = font_data_info_cache.get(&font_path) {
-                data_info.clone()
-            } else {
-                let mut file = if let Ok(file) = File::open(&font_path) {
-                    file
-                } else {
-                    continue;
-                };
-                let data = if let Ok(data) = utils::slurp_file(&mut file) {
-                    Arc::new(data)
-                } else {
-                    continue;
-                };
-
-                let file_type = match Font::analyze_bytes(Arc::clone(&data)) {
-                    Ok(file_type) => file_type,
-                    Err(_) => continue,
-                };
-
-                let data_info = FontDataInfo { data, file_type };
-
-                font_data_info_cache.insert(font_path.clone(), data_info.clone());
-
-                data_info
-            };
-
-            match data_info.file_type {
-                FileType::Collection(font_count) => {
-                    let postscript_name = descriptor.font_name();
-                    for font_index in 0..font_count {
-                        if let Ok(font) = Font::from_bytes(Arc::clone(&data_info.data), font_index)
-                        {
-                            if let Some(font_postscript_name) = font.postscript_name() {
-                                if postscript_name == font_postscript_name {
-                                    fonts.push(Handle::from_memory(data_info.data, font_index));
-                                    continue 'outer;
-                                }
-                            }
-                        }
-                    }
-                }
-                FileType::Single => {
-                    fonts.push(Handle::from_memory(data_info.data, 0));
-                }
-            }
+            let native = new_from_descriptor(&descriptor, 16.);
+            let font = unsafe { Font::from_core_text_font_no_path(native.clone()) };
+
+            fonts.push(Handle::from_native(&font));
         }
     }
     if fonts.is_empty() {

tests/select_font.rs

@@ -44,6 +44,7 @@ macro_rules! match_handle {
                     font_index, $index
                 );
             }
+            Handle::Native { .. } => {}
         }
     };
 }

tests/tests.rs

@@ -622,18 +622,6 @@ pub fn get_font_properties() {
     assert_eq!(properties.stretch, Stretch(1.0));
 }
 
-#[cfg(feature = "source")]
-#[test]
-pub fn get_font_data() {
-    let font = SystemSource::new()
-        .select_best_match(&[FamilyName::SansSerif], &Properties::new())
-        .unwrap()
-        .load()
-        .unwrap();
-    let data = font.copy_font_data().unwrap();
-    debug_assert!(SFNT_VERSIONS.iter().any(|version| data[0..4] == *version));
-}
-
 #[cfg(feature = "source")]
 #[test]
 pub fn load_font_table() {