1 files changed, 208 insertions, 0 deletions
diff --git a/gfx/wr/webrender/src/glyph_cache.rs b/gfx/wr/webrender/src/glyph_cache.rs
new file mode 100644
index 0000000000..0f895e3212
--- /dev/null
+++ b/gfx/wr/webrender/src/glyph_cache.rs
@@ -0,0 +1,208 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use api::{FontKey, FontInstanceKey, IdNamespace};
+use glyph_rasterizer::{FontInstance, GlyphFormat, GlyphKey, GlyphRasterizer};
+use crate::internal_types::{FrameId, FrameStamp, FastHashMap};
+use crate::resource_cache::ResourceClassCache;
+use std::sync::Arc;
+use crate::texture_cache::{EvictionNotice, TextureCache};
+use crate::texture_cache::TextureCacheHandle;
+
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+#[derive(Clone, Debug)]
+pub struct CachedGlyphInfo {
+    pub format: GlyphFormat,
+    pub texture_cache_handle: TextureCacheHandle,
+}
+
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+pub enum GlyphCacheEntry {
+    // A glyph that has been successfully rasterized.
+    Cached(CachedGlyphInfo),
+    // A glyph that should not be rasterized (i.e. a space).
+    Blank,
+    // A glyph that has been submitted to the font backend for rasterization,
+    // but is still pending a result.
+    #[allow(dead_code)]
+    Pending,
+}
+
+impl GlyphCacheEntry {
+    fn has_been_evicted(&self, texture_cache: &TextureCache) -> bool {
+        match *self {
+            GlyphCacheEntry::Cached(ref glyph) => {
+                !texture_cache.is_allocated(&glyph.texture_cache_handle)
+            }
+            GlyphCacheEntry::Pending | GlyphCacheEntry::Blank => false,
+        }
+    }
+}
+
+#[allow(dead_code)]
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+#[derive(Clone)]
+pub enum CachedGlyphData {
+    Memory(Arc<Vec<u8>>),
+    Gpu,
+}
+
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+#[derive(Default)]
+pub struct GlyphKeyCacheInfo {
+    eviction_notice: EvictionNotice,
+    #[cfg(debug_assertions)]
+    #[allow(dead_code)]
+    #[cfg_attr(feature = "replay", serde(default))]
+    last_frame_used: FrameId,
+}
+
+pub type GlyphKeyCache = ResourceClassCache<GlyphKey, GlyphCacheEntry, GlyphKeyCacheInfo>;
+
+impl GlyphKeyCache {
+    pub fn eviction_notice(&self) -> &EvictionNotice {
+        &self.user_data.eviction_notice
+    }
+
+    fn clear_glyphs(&mut self) {
+        self.clear();
+    }
+
+    pub fn add_glyph(&mut self, key: GlyphKey, value: GlyphCacheEntry) {
+        self.insert(key, value);
+    }
+
+    fn clear_evicted(&mut self, texture_cache: &TextureCache) {
+        if self.eviction_notice().check() {
+            // If there are evictions, filter out any glyphs evicted from the
+            // texture cache from the glyph key cache.
+            self.retain(|_, entry| !entry.has_been_evicted(texture_cache));
+        }
+    }
+}
+
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+pub struct GlyphCache {
+    glyph_key_caches: FastHashMap<FontInstance, GlyphKeyCache>,
+    current_frame: FrameId,
+}
+
+impl GlyphCache {
+    pub fn new() -> Self {
+        GlyphCache {
+            glyph_key_caches: FastHashMap::default(),
+            current_frame: Default::default(),
+        }
+    }
+
+    pub fn insert_glyph_key_cache_for_font(&mut self, font: &FontInstance) -> &mut GlyphKeyCache {
+        let cache = self.glyph_key_caches
+                        .entry(font.clone())
+                        .or_insert_with(GlyphKeyCache::new);
+        #[cfg(debug_assertions)]
+        {
+            cache.user_data.last_frame_used = self.current_frame;
+        }
+        cache
+    }
+
+    pub fn get_glyph_key_cache_for_font_mut(&mut self, font: &FontInstance) -> &mut GlyphKeyCache {
+        self.glyph_key_caches
+            .get_mut(font)
+            .expect("BUG: Unable to find glyph key cache!")
+    }
+
+    pub fn get_glyph_key_cache_for_font(&self, font: &FontInstance) -> &GlyphKeyCache {
+        self.glyph_key_caches
+            .get(font)
+            .expect("BUG: Unable to find glyph key cache!")
+    }
+
+    pub fn clear(&mut self) {
+        for (_, glyph_key_cache) in &mut self.glyph_key_caches {
+            glyph_key_cache.clear()
+        }
+        // We use this in on_memory_pressure where retaining memory allocations
+        // isn't desirable, so we completely remove the hash map instead of clearing it.
+        self.glyph_key_caches = FastHashMap::default();
+    }
+
+    pub fn delete_font_instances(
+        &mut self,
+        instance_keys: &[FontInstanceKey],
+        glyph_rasterizer: &mut GlyphRasterizer,
+    ) {
+        self.glyph_key_caches.retain(|k, cache| {
+            if instance_keys.contains(&k.instance_key) {
+                cache.clear_glyphs();
+                glyph_rasterizer.delete_font_instance(k);
+                false
+            } else {
+                true
+            }
+        });
+    }
+
+    pub fn delete_fonts(&mut self, font_keys: &[FontKey]) {
+        self.glyph_key_caches.retain(|k, cache| {
+            if font_keys.contains(&k.font_key) {
+                cache.clear_glyphs();
+                false
+            } else {
+                true
+            }
+        });
+    }
+
+    pub fn clear_namespace(&mut self, namespace: IdNamespace) {
+        self.glyph_key_caches.retain(|k, cache| {
+            if k.font_key.0 == namespace {
+                cache.clear_glyphs();
+                false
+            } else {
+                true
+            }
+        });
+    }
+
+    /// Clear out evicted entries from glyph key caches.
+    fn clear_evicted(&mut self, texture_cache: &TextureCache) {
+        for cache in self.glyph_key_caches.values_mut() {
+            // Scan for any glyph key caches that have evictions.
+            cache.clear_evicted(texture_cache);
+        }
+    }
+
+    /// If possible, remove entirely any empty glyph key caches.
+    fn clear_empty_caches(&mut self, glyph_rasterizer: &mut GlyphRasterizer) {
+        self.glyph_key_caches.retain(|key, cache| {
+            // Discard the glyph key cache if it has no valid glyphs.
+            if cache.is_empty() {
+                glyph_rasterizer.delete_font_instance(key);
+                false
+            } else {
+                true
+            }
+        });
+    }
+
+    pub fn begin_frame(
+        &mut self,
+        stamp: FrameStamp,
+        texture_cache: &mut TextureCache,
+        glyph_rasterizer: &mut GlyphRasterizer,
+    ) {
+        profile_scope!("begin_frame");
+        self.current_frame = stamp.frame_id();
+        self.clear_evicted(texture_cache);
+        // Clearing evicted glyphs and pruning excess usage might have produced empty caches,
+        // so get rid of them if possible.
+        self.clear_empty_caches(glyph_rasterizer);
+    }
+}