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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.
#![deny(unsafe_code)]
use css::matching::{ApplicableDeclarationsCache, StyleSharingCandidateCache};
use canvas_traits::CanvasMsg;
use msg::compositor_msg::LayerId;
use fnv::FnvHasher;
use euclid::{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, ImageResponse, ImageState};
use net_traits::image_cache_task::{UsePlaceholder};
use script::layout_interface::{Animation, LayoutChan, ReflowGoal};
use std::cell::{RefCell, RefMut};
use std::collections::HashMap;
use std::collections::hash_state::DefaultState;
use std::rc::Rc;
use std::sync::{Arc, Mutex};
use std::sync::mpsc::{channel, Sender};
use style::selector_matching::Stylist;
use url::Url;
use util::geometry::Au;
use util::mem::HeapSizeOf;
use util::opts;
struct LocalLayoutContext {
font_context: RefCell<FontContext>,
applicable_declarations_cache: RefCell<ApplicableDeclarationsCache>,
style_sharing_candidate_cache: RefCell<StyleSharingCandidateCache>,
}
impl HeapSizeOf for LocalLayoutContext {
// FIXME(njn): measure other fields eventually.
fn heap_size_of_children(&self) -> usize {
self.font_context.heap_size_of_children()
}
}
thread_local!(static LOCAL_CONTEXT_KEY: RefCell<Option<Rc<LocalLayoutContext>>> = RefCell::new(None));
pub fn heap_size_of_local_context() -> usize {
LOCAL_CONTEXT_KEY.with(|r| {
r.borrow().clone().map_or(0, |context| context.heap_size_of_children())
})
}
fn create_or_get_local_context(shared_layout_context: &SharedLayoutContext)
-> Rc<LocalLayoutContext> {
LOCAL_CONTEXT_KEY.with(|r| {
let mut r = r.borrow_mut();
if let Some(context) = r.clone() {
if shared_layout_context.screen_size_changed {
context.applicable_declarations_cache.borrow_mut().evict_all();
}
context
} else {
let context = Rc::new(LocalLayoutContext {
font_context: RefCell::new(FontContext::new(shared_layout_context.font_cache_task.clone())),
applicable_declarations_cache: RefCell::new(ApplicableDeclarationsCache::new()),
style_sharing_candidate_cache: RefCell::new(StyleSharingCandidateCache::new()),
});
*r = Some(context.clone());
context
}
})
}
/// 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>,
/// A channel to send canvas renderers to paint task, in order to correctly paint the layers
pub canvas_layers_sender: Sender<(LayerId, Option<Arc<Mutex<Sender<CanvasMsg>>>>)>,
/// The visible rects for each layer, as reported to us by the compositor.
pub visible_rects: Arc<HashMap<LayerId, Rect<Au>, DefaultState<FnvHasher>>>,
/// Why is this reflow occurring
pub goal: ReflowGoal,
}
// FIXME(#6569) This implementations is unsound:
// XXX UNSOUND!!! for image_cache_task
// XXX UNSOUND!!! for image_cache_sender
// XXX UNSOUND!!! for constellation_chan
// XXX UNSOUND!!! for layout_chan
// XXX UNSOUND!!! for font_cache_task
// XXX UNSOUND!!! for stylist
// XXX UNSOUND!!! for new_animations_sender
// XXX UNSOUND!!! for canvas_layers_sender
#[allow(unsafe_code)]
unsafe impl Sync for SharedLayoutContext {}
pub struct LayoutContext<'a> {
pub shared: &'a SharedLayoutContext,
cached_local_layout_context: Rc<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(&self) -> RefMut<FontContext> {
self.cached_local_layout_context.font_context.borrow_mut()
}
#[inline(always)]
pub fn applicable_declarations_cache(&self) -> RefMut<ApplicableDeclarationsCache> {
self.cached_local_layout_context.applicable_declarations_cache.borrow_mut()
}
#[inline(always)]
pub fn style_sharing_candidate_cache(&self) -> RefMut<StyleSharingCandidateCache> {
self.cached_local_layout_context.style_sharing_candidate_cache.borrow_mut()
}
pub fn get_or_request_image(&self, url: Url, use_placeholder: UsePlaceholder)
-> Option<Arc<Image>> {
// See if the image is already available
let result = self.shared.image_cache_task.get_image_if_available(url.clone(),
use_placeholder);
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() ||
opts::get().exit_after_load;
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);
match sync_rx.recv().unwrap().image_response {
ImageResponse::Loaded(image) |
ImageResponse::PlaceholderLoaded(image) => Some(image),
ImageResponse::None => None,
}
}
// 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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