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/* 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/. */
//! Data needed by the layout task.
#![allow(unsafe_code)]
use css::matching::{ApplicableDeclarationsCache, StyleSharingCandidateCache};
use geom::{Rect, Size2D};
use gfx::display_list::OpaqueNode;
use gfx::font_cache_task::FontCacheTask;
use gfx::font_context::FontContext;
use msg::constellation_msg::ConstellationChan;
use net_traits::image::base::Image;
use net_traits::image_cache_task::{ImageCacheChan, ImageCacheTask, ImageState};
use script::layout_interface::{Animation, LayoutChan, ReflowGoal};
use std::boxed;
use std::cell::Cell;
use std::ptr;
use std::sync::Arc;
use std::sync::mpsc::{channel, Sender};
use style::selector_matching::Stylist;
use url::Url;
use util::geometry::Au;
use util::opts;
struct LocalLayoutContext {
font_context: FontContext,
applicable_declarations_cache: ApplicableDeclarationsCache,
style_sharing_candidate_cache: StyleSharingCandidateCache,
}
thread_local!(static LOCAL_CONTEXT_KEY: Cell<*mut LocalLayoutContext> = Cell::new(ptr::null_mut()));
fn create_or_get_local_context(shared_layout_context: &SharedLayoutContext)
-> *mut LocalLayoutContext {
LOCAL_CONTEXT_KEY.with(|ref r| {
if r.get().is_null() {
let context = box LocalLayoutContext {
font_context: FontContext::new(shared_layout_context.font_cache_task.clone()),
applicable_declarations_cache: ApplicableDeclarationsCache::new(),
style_sharing_candidate_cache: StyleSharingCandidateCache::new(),
};
r.set(unsafe { boxed::into_raw(context) });
} else if shared_layout_context.screen_size_changed {
unsafe {
(*r.get()).applicable_declarations_cache.evict_all();
}
}
r.get()
})
}
/// Layout information shared among all workers. This must be thread-safe.
pub struct SharedLayoutContext {
/// The shared image cache task.
pub image_cache_task: ImageCacheTask,
/// A channel for the image cache to send responses to.
pub image_cache_sender: ImageCacheChan,
/// The current screen size.
pub screen_size: Size2D<Au>,
/// Screen sized changed?
pub screen_size_changed: bool,
/// A channel up to the constellation.
pub constellation_chan: ConstellationChan,
/// A channel up to the layout task.
pub layout_chan: LayoutChan,
/// Interface to the font cache task.
pub font_cache_task: FontCacheTask,
/// The CSS selector stylist.
///
/// FIXME(#2604): Make this no longer an unsafe pointer once we have fast `RWArc`s.
pub stylist: *const Stylist,
/// The root node at which we're starting the layout.
pub reflow_root: Option<OpaqueNode>,
/// The URL.
pub url: Url,
/// The dirty rectangle, used during display list building.
pub dirty: Rect<Au>,
/// Starts at zero, and increased by one every time a layout completes.
/// This can be used to easily check for invalid stale data.
pub generation: u32,
/// A channel on which new animations that have been triggered by style recalculation can be
/// sent.
pub new_animations_sender: Sender<Animation>,
/// Why is this reflow occurring
pub goal: ReflowGoal,
}
pub struct SharedLayoutContextWrapper(pub *const SharedLayoutContext);
unsafe impl Send for SharedLayoutContextWrapper {}
pub struct LayoutContext<'a> {
pub shared: &'a SharedLayoutContext,
cached_local_layout_context: *mut LocalLayoutContext,
}
impl<'a> LayoutContext<'a> {
pub fn new(shared_layout_context: &'a SharedLayoutContext) -> LayoutContext<'a> {
let local_context = create_or_get_local_context(shared_layout_context);
LayoutContext {
shared: shared_layout_context,
cached_local_layout_context: local_context,
}
}
#[inline(always)]
pub fn font_context<'b>(&'b self) -> &'b mut FontContext {
unsafe {
let cached_context = &mut *self.cached_local_layout_context;
&mut cached_context.font_context
}
}
#[inline(always)]
pub fn applicable_declarations_cache<'b>(&'b self) -> &'b mut ApplicableDeclarationsCache {
unsafe {
let cached_context = &mut *self.cached_local_layout_context;
&mut cached_context.applicable_declarations_cache
}
}
#[inline(always)]
pub fn style_sharing_candidate_cache<'b>(&'b self) -> &'b mut StyleSharingCandidateCache {
unsafe {
let cached_context = &mut *self.cached_local_layout_context;
&mut cached_context.style_sharing_candidate_cache
}
}
pub fn get_or_request_image(&self, url: Url) -> Option<Arc<Image>> {
// See if the image is already available
let result = self.shared.image_cache_task.get_image_if_available(url.clone());
match result {
Ok(image) => Some(image),
Err(state) => {
// If we are emitting an output file, then we need to block on
// image load or we risk emitting an output file missing the image.
let is_sync = opts::get().output_file.is_some();
match (state, is_sync) {
// Image failed to load, so just return nothing
(ImageState::LoadError, _) => None,
// Not loaded, test mode - load the image synchronously
(_, true) => {
let (sync_tx, sync_rx) = channel();
self.shared.image_cache_task.request_image(url,
ImageCacheChan(sync_tx),
None);
sync_rx.recv().unwrap().image
}
// Not yet requested, async mode - request image from the cache
(ImageState::NotRequested, false) => {
self.shared.image_cache_task.request_image(url,
self.shared.image_cache_sender.clone(),
None);
None
}
// Image has been requested, is still pending. Return no image
// for this paint loop. When the image loads it will trigger
// a reflow and/or repaint.
(ImageState::Pending, false) => None,
}
}
}
}
}
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