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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 app_units::Au;
use canvas_traits::CanvasMsg;
use css::matching::{ApplicableDeclarationsCache, StyleSharingCandidateCache};
use euclid::{Rect, Size2D};
use fnv::FnvHasher;
use gfx::display_list::OpaqueNode;
use gfx::font_cache_task::FontCacheTask;
use gfx::font_context::FontContext;
use ipc_channel::ipc::{self, IpcSender};
use msg::compositor_msg::LayerId;
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, ReflowGoal};
use std::cell::{RefCell, RefMut};
use std::collections::HashMap;
use std::collections::hash_state::DefaultState;
use std::rc::Rc;
use std::sync::mpsc::{Sender, channel};
use std::sync::{Arc, Mutex, RwLock};
use style::selector_matching::Stylist;
use style_traits::ParseErrorReporter;
use url::Url;
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 font_cache_task = shared_layout_context.font_cache_task.lock().unwrap().clone();
let context = Rc::new(LocalLayoutContext {
font_context: RefCell::new(FontContext::new(font_cache_task)),
applicable_declarations_cache: RefCell::new(ApplicableDeclarationsCache::new()),
style_sharing_candidate_cache: RefCell::new(StyleSharingCandidateCache::new()),
});
*r = Some(context.clone());
context
}
})
}
pub struct StylistWrapper(pub *const Stylist);
// FIXME(#6569) This implementation is unsound.
#[allow(unsafe_code)]
unsafe impl Sync for StylistWrapper {}
/// 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: Mutex<ImageCacheChan>,
/// The current viewport size.
pub viewport_size: Size2D<Au>,
/// Screen sized changed?
pub screen_size_changed: bool,
/// Interface to the font cache task.
pub font_cache_task: Mutex<FontCacheTask>,
/// The CSS selector stylist.
///
/// FIXME(#2604): Make this no longer an unsafe pointer once we have fast `RWArc`s.
pub stylist: StylistWrapper,
/// The URL.
pub url: Url,
/// 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: Mutex<Sender<Animation>>,
/// A channel to send canvas renderers to paint task, in order to correctly paint the layers
pub canvas_layers_sender: Mutex<Sender<(LayerId, IpcSender<CanvasMsg>)>>,
/// The visible rects for each layer, as reported to us by the compositor.
pub visible_rects: Arc<HashMap<LayerId, Rect<Au>, DefaultState<FnvHasher>>>,
/// The animations that are currently running.
pub running_animations: Arc<RwLock<HashMap<OpaqueNode, Vec<Animation>>>>,
/// The list of animations that have expired since the last style recalculation.
pub expired_animations: Arc<RwLock<HashMap<OpaqueNode, Vec<Animation>>>>,
/// Why is this reflow occurring
pub goal: ReflowGoal,
///The CSS error reporter for all CSS loaded in this layout thread
pub error_reporter: Box<ParseErrorReporter + Sync>
}
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.find_image(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) = ipc::channel().unwrap();
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) => {
let sender = self.shared.image_cache_sender.lock().unwrap().clone();
self.shared.image_cache_task.request_image(url, sender, 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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