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daafd66ee8
This is a grab bag of performance improvements that significantly improve style recalculation, layout, and painting on a few static pages. Let me know if you'd like me to split this PR up. r? @glennw Source-Repo: https://github.com/servo/servo Source-Revision: 156ca98236a57ee52ff5b68741bc7783ba073612
213 lines
6.9 KiB
Rust
213 lines
6.9 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 http://mozilla.org/MPL/2.0/. */
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use geom::{Point2D, Rect, Size2D};
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use std::mem;
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use std::string;
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use std::rc::Rc;
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use std::cell::RefCell;
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use servo_util::cache::{Cache, HashCache};
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use servo_util::smallvec::{SmallVec, SmallVec1};
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use style::computed_values::{font_variant, font_weight};
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use style::style_structs::Font as FontStyle;
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use sync::Arc;
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use servo_util::geometry::Au;
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use platform::font_context::FontContextHandle;
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use platform::font::{FontHandle, FontTable};
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use text::glyph::{GlyphStore, GlyphId};
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use text::shaping::ShaperMethods;
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use text::{Shaper, TextRun};
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use font_template::FontTemplateDescriptor;
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use platform::font_template::FontTemplateData;
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// FontHandle encapsulates access to the platform's font API,
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// e.g. quartz, FreeType. It provides access to metrics and tables
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// needed by the text shaper as well as access to the underlying font
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// resources needed by the graphics layer to draw glyphs.
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pub trait FontHandleMethods {
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fn new_from_template(fctx: &FontContextHandle, template: Arc<FontTemplateData>, pt_size: Option<f64>)
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-> Result<Self,()>;
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fn get_template(&self) -> Arc<FontTemplateData>;
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fn family_name(&self) -> String;
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fn face_name(&self) -> String;
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fn is_italic(&self) -> bool;
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fn boldness(&self) -> font_weight::T;
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fn glyph_index(&self, codepoint: char) -> Option<GlyphId>;
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fn glyph_h_advance(&self, GlyphId) -> Option<FractionalPixel>;
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fn glyph_h_kerning(&self, GlyphId, GlyphId) -> FractionalPixel;
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fn get_metrics(&self) -> FontMetrics;
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fn get_table_for_tag(&self, FontTableTag) -> Option<FontTable>;
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}
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// Used to abstract over the shaper's choice of fixed int representation.
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pub type FractionalPixel = f64;
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pub type FontTableTag = u32;
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pub trait FontTableTagConversions {
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fn tag_to_str(&self) -> String;
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}
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impl FontTableTagConversions for FontTableTag {
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fn tag_to_str(&self) -> String {
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unsafe {
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let reversed = string::raw::from_buf_len(mem::transmute(self), 4);
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return String::from_chars([reversed.as_slice().char_at(3),
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reversed.as_slice().char_at(2),
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reversed.as_slice().char_at(1),
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reversed.as_slice().char_at(0)]);
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}
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}
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}
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pub trait FontTableMethods {
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fn with_buffer(&self, |*const u8, uint|);
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}
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#[deriving(Clone)]
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pub struct FontMetrics {
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pub underline_size: Au,
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pub underline_offset: Au,
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pub strikeout_size: Au,
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pub strikeout_offset: Au,
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pub leading: Au,
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pub x_height: Au,
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pub em_size: Au,
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pub ascent: Au,
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pub descent: Au,
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pub max_advance: Au,
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pub average_advance: Au,
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pub line_gap: Au,
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}
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pub type SpecifiedFontStyle = FontStyle;
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pub type UsedFontStyle = FontStyle;
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pub struct Font {
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pub handle: FontHandle,
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pub metrics: FontMetrics,
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pub variant: font_variant::T,
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pub descriptor: FontTemplateDescriptor,
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pub requested_pt_size: f64,
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pub actual_pt_size: f64,
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pub shaper: Option<Shaper>,
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pub shape_cache: HashCache<String, Arc<GlyphStore>>,
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pub glyph_advance_cache: HashCache<u32, FractionalPixel>,
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}
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impl Font {
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pub fn shape_text(&mut self, text: &str, is_whitespace: bool) -> Arc<GlyphStore> {
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self.make_shaper();
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let shaper = &self.shaper;
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match self.shape_cache.find_equiv(&text) {
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None => {}
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Some(glyphs) => return (*glyphs).clone(),
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}
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let mut glyphs = GlyphStore::new(text.char_len() as int, is_whitespace);
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shaper.as_ref().unwrap().shape_text(text, &mut glyphs);
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let glyphs = Arc::new(glyphs);
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self.shape_cache.insert(text.to_string(), glyphs.clone());
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glyphs
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}
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fn make_shaper<'a>(&'a mut self) -> &'a Shaper {
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// fast path: already created a shaper
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match self.shaper {
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Some(ref shaper) => {
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let s: &'a Shaper = shaper;
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return s;
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},
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None => {}
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}
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let shaper = Shaper::new(self);
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self.shaper = Some(shaper);
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self.shaper.as_ref().unwrap()
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}
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pub fn get_table_for_tag(&self, tag: FontTableTag) -> Option<FontTable> {
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let result = self.handle.get_table_for_tag(tag);
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let status = if result.is_some() { "Found" } else { "Didn't find" };
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debug!("{:s} font table[{:s}] with family={}, face={}",
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status, tag.tag_to_str(),
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self.handle.family_name(), self.handle.face_name());
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return result;
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}
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pub fn glyph_index(&self, codepoint: char) -> Option<GlyphId> {
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let codepoint = match self.variant {
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font_variant::small_caps => codepoint.to_uppercase(),
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font_variant::normal => codepoint,
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};
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self.handle.glyph_index(codepoint)
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}
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pub fn glyph_h_kerning(&mut self, first_glyph: GlyphId, second_glyph: GlyphId) -> FractionalPixel {
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self.handle.glyph_h_kerning(first_glyph, second_glyph)
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}
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pub fn glyph_h_advance(&mut self, glyph: GlyphId) -> FractionalPixel {
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let handle = &self.handle;
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self.glyph_advance_cache.find_or_create(&glyph, |glyph| {
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match handle.glyph_h_advance(*glyph) {
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Some(adv) => adv,
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None => 10f64 as FractionalPixel // FIXME: Need fallback strategy
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}
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})
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}
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}
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pub struct FontGroup {
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pub fonts: SmallVec1<Rc<RefCell<Font>>>,
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}
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impl FontGroup {
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pub fn new(fonts: SmallVec1<Rc<RefCell<Font>>>) -> FontGroup {
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FontGroup {
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fonts: fonts,
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}
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}
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pub fn create_textrun(&self, text: String) -> TextRun {
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assert!(self.fonts.len() > 0);
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// TODO(Issue #177): Actually fall back through the FontGroup when a font is unsuitable.
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TextRun::new(&mut *self.fonts.get(0).borrow_mut(), text.clone())
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}
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}
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pub struct RunMetrics {
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// may be negative due to negative width (i.e., kerning of '.' in 'P.T.')
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pub advance_width: Au,
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pub ascent: Au, // nonzero
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pub descent: Au, // nonzero
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// this bounding box is relative to the left origin baseline.
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// so, bounding_box.position.y = -ascent
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pub bounding_box: Rect<Au>
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}
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impl RunMetrics {
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pub fn new(advance: Au, ascent: Au, descent: Au) -> RunMetrics {
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let bounds = Rect(Point2D(Au(0), -ascent),
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Size2D(advance, ascent + descent));
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// TODO(Issue #125): support loose and tight bounding boxes; using the
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// ascent+descent and advance is sometimes too generous and
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// looking at actual glyph extents can yield a tighter box.
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RunMetrics {
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advance_width: advance,
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bounding_box: bounds,
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ascent: ascent,
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descent: descent,
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}
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}
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}
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