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6b2fa91357
Now that `FontTemplateData` is more or less the same on all platforms, it can be removed. This is a preparatory change for a full refactor of the font system on Servo. The major changes here are: - Remove `FontTemplateData` and move its members into `FontTemplate` - Make `FontTemplate` have full interior mutability instead of only the `FontTemplateData` member. This is preparation for having these data types `Send` and `Sync` with locking. - Remove the strong/weak reference concept for font data. In practice, all font data references were strong, so this was never fully complete. Instead of using this approach, the new font system will use a central font data cache with references associated to layouts. - The `CTFont` cache is now a global cache, so `CTFont`s can be shared between threads. The cache is cleared when clearing font caches. A benefit of this change (apart from `CTFont` sharing) is that font data loading is platform-independent now.
74 lines
3 KiB
Rust
74 lines
3 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
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use std::collections::HashMap;
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use std::sync::OnceLock;
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use app_units::Au;
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use core_graphics::data_provider::CGDataProvider;
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use core_graphics::font::CGFont;
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use core_text::font::CTFont;
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use parking_lot::RwLock;
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use crate::font_cache_thread::FontIdentifier;
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use crate::font_template::{FontTemplate, FontTemplateRef, FontTemplateRefMethods};
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// A cache of `CTFont` to avoid having to create `CTFont` instances over and over. It is
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// always possible to create a `CTFont` using a `FontTemplate` even if it isn't in this
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// cache.
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static CTFONT_CACHE: OnceLock<RwLock<HashMap<FontIdentifier, CachedCTFont>>> = OnceLock::new();
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/// A [`HashMap`] of cached [`CTFont`] for a single [`FontIdentifier`]. There is one [`CTFont`]
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/// for each cached font size.
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type CachedCTFont = HashMap<Au, CTFont>;
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pub(crate) trait CoreTextFontTemplateMethods {
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/// Retrieves a [`CTFont`] instance, instantiating it if necessary if it is not
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/// stored in the shared Core Text font cache.
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fn core_text_font(&self, pt_size: f64) -> Option<CTFont>;
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}
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impl CoreTextFontTemplateMethods for FontTemplateRef {
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fn core_text_font(&self, pt_size: f64) -> Option<CTFont> {
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//// If you pass a zero font size to one of the Core Text APIs, it'll replace it with
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//// 12.0. We don't want that! (Issue #10492.)
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let clamped_pt_size = pt_size.max(0.01);
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let au_size = Au::from_f64_px(clamped_pt_size);
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let cache = CTFONT_CACHE.get_or_init(Default::default);
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let identifier = self.borrow().identifier.clone();
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{
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let cache = cache.read();
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if let Some(core_text_font) = cache
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.get(&identifier)
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.and_then(|identifier_cache| identifier_cache.get(&au_size))
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{
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return Some(core_text_font.clone());
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}
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}
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let mut cache = cache.write();
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let identifier_cache = cache.entry(identifier).or_insert_with(Default::default);
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// It could be that between the time of the cache miss above and now, after the write lock
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// on the cache has been acquired, the cache was populated with the data that we need. Thus
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// check again and return the CTFont if it is is already cached.
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if let Some(core_text_font) = identifier_cache.get(&au_size) {
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return Some(core_text_font.clone());
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}
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let provider = CGDataProvider::from_buffer(self.data());
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let cgfont = CGFont::from_data_provider(provider).ok()?;
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let core_text_font = core_text::font::new_from_CGFont(&cgfont, clamped_pt_size);
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identifier_cache.insert(au_size, core_text_font.clone());
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Some(core_text_font)
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}
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}
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impl FontTemplate {
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pub(crate) fn clear_core_text_font_cache() {
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let cache = CTFONT_CACHE.get_or_init(Default::default);
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cache.write().clear();
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}
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}
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