servo/components/layout/context.rs
Emilio Cobos Álvarez 2a499d5a0b
layout: Stop storing PrecomputedStyleData in LayoutNode
Use the SharedStyleContext instead.
2016-04-29 22:54:48 +02:00

241 lines
9.7 KiB
Rust

/* 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 thread.
// for thread_local
#![allow(unsafe_code)]
use app_units::Au;
use euclid::Rect;
use fnv::FnvHasher;
use gfx::display_list::WebRenderImageInfo;
use gfx::font_cache_thread::FontCacheThread;
use gfx::font_context::FontContext;
use gfx_traits::LayerId;
use heapsize::HeapSizeOf;
use ipc_channel::ipc::{self, IpcSharedMemory};
use net_traits::image::base::Image;
use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheThread, ImageResponse, ImageState};
use net_traits::image_cache_thread::{ImageOrMetadataAvailable, UsePlaceholder};
use std::cell::{RefCell, RefMut};
use std::collections::HashMap;
use std::hash::BuildHasherDefault;
use std::rc::Rc;
use std::sync::{Arc, Mutex, RwLock};
use style::context::{LocalStyleContext, StyleContext};
use style::matching::{ApplicableDeclarationsCache, StyleSharingCandidateCache};
use style::properties::ServoComputedValues;
use style::selector_impl::ServoSelectorImpl;
use style::servo::SharedStyleContext;
use url::Url;
use util::opts;
struct LocalLayoutContext {
style_context: LocalStyleContext<ServoComputedValues>,
font_context: RefCell<FontContext>,
}
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())
})
}
// Keep this implementation in sync with the one in ports/geckolib/traversal.rs.
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.style_context.screen_size_changed {
context.style_context.applicable_declarations_cache.borrow_mut().evict_all();
}
context
} else {
let font_cache_thread = shared_layout_context.font_cache_thread.lock().unwrap().clone();
let context = Rc::new(LocalLayoutContext {
style_context: LocalStyleContext {
applicable_declarations_cache: RefCell::new(ApplicableDeclarationsCache::new()),
style_sharing_candidate_cache: RefCell::new(StyleSharingCandidateCache::new()),
},
font_context: RefCell::new(FontContext::new(font_cache_thread)),
});
*r = Some(context.clone());
context
}
})
}
/// Layout information shared among all workers. This must be thread-safe.
pub struct SharedLayoutContext {
/// Bits shared by the layout and style system.
pub style_context: SharedStyleContext,
/// The shared image cache thread.
pub image_cache_thread: ImageCacheThread,
/// A channel for the image cache to send responses to.
pub image_cache_sender: Mutex<ImageCacheChan>,
/// Interface to the font cache thread.
pub font_cache_thread: Mutex<FontCacheThread>,
/// The URL.
pub url: Url,
/// The visible rects for each layer, as reported to us by the compositor.
pub visible_rects: Arc<HashMap<LayerId, Rect<Au>, BuildHasherDefault<FnvHasher>>>,
/// A cache of WebRender image info.
pub webrender_image_cache: Arc<RwLock<HashMap<(Url, UsePlaceholder),
WebRenderImageInfo,
BuildHasherDefault<FnvHasher>>>>,
}
pub struct LayoutContext<'a> {
pub shared: &'a SharedLayoutContext,
cached_local_layout_context: Rc<LocalLayoutContext>,
}
impl<'a> StyleContext<'a, ServoSelectorImpl> for LayoutContext<'a> {
fn shared_context(&self) -> &'a SharedStyleContext {
&self.shared.style_context
}
fn local_context(&self) -> &LocalStyleContext<ServoComputedValues> {
&self.cached_local_layout_context.style_context
}
}
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 style_context(&self) -> &SharedStyleContext {
&self.shared.style_context
}
#[inline(always)]
pub fn font_context(&self) -> RefMut<FontContext> {
self.cached_local_layout_context.font_context.borrow_mut()
}
fn get_or_request_image_synchronously(&self, url: Url, use_placeholder: UsePlaceholder)
-> Option<Arc<Image>> {
debug_assert!(opts::get().output_file.is_some() || opts::get().exit_after_load);
// See if the image is already available
let result = self.shared.image_cache_thread.find_image(url.clone(), use_placeholder);
match result {
Ok(image) => return Some(image),
Err(ImageState::LoadError) => {
// Image failed to load, so just return nothing
return None
}
Err(_) => {}
}
// 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 (sync_tx, sync_rx) = ipc::channel().unwrap();
self.shared.image_cache_thread.request_image(url, ImageCacheChan(sync_tx), None);
loop {
match sync_rx.recv() {
Err(_) => return None,
Ok(response) => {
match response.image_response {
ImageResponse::Loaded(image) | ImageResponse::PlaceholderLoaded(image) => {
return Some(image)
}
ImageResponse::None | ImageResponse::MetadataLoaded(_) => {}
}
}
}
}
}
pub fn get_or_request_image_or_meta(&self, url: Url, use_placeholder: UsePlaceholder)
-> Option<ImageOrMetadataAvailable> {
// If we are emitting an output file, load the image synchronously.
if opts::get().output_file.is_some() || opts::get().exit_after_load {
return self.get_or_request_image_synchronously(url, use_placeholder)
.map(|img| ImageOrMetadataAvailable::ImageAvailable(img));
}
// See if the image is already available
let result = self.shared.image_cache_thread.find_image_or_metadata(url.clone(),
use_placeholder);
match result {
Ok(image_or_metadata) => Some(image_or_metadata),
// Image failed to load, so just return nothing
Err(ImageState::LoadError) => None,
// Not yet requested, async mode - request image or metadata from the cache
Err(ImageState::NotRequested) => {
let sender = self.shared.image_cache_sender.lock().unwrap().clone();
self.shared.image_cache_thread.request_image_and_metadata(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.
Err(ImageState::Pending) => None,
}
}
pub fn get_webrender_image_for_url(&self,
url: &Url,
use_placeholder: UsePlaceholder,
fetch_image_data_as_well: bool)
-> Option<(WebRenderImageInfo, Option<IpcSharedMemory>)> {
if !fetch_image_data_as_well {
let webrender_image_cache = self.shared.webrender_image_cache.read().unwrap();
if let Some(existing_webrender_image) =
webrender_image_cache.get(&((*url).clone(), use_placeholder)) {
return Some(((*existing_webrender_image).clone(), None))
}
}
match self.get_or_request_image_or_meta((*url).clone(), use_placeholder) {
Some(ImageOrMetadataAvailable::ImageAvailable(image)) => {
let image_info = WebRenderImageInfo::from_image(&*image);
if image_info.key.is_none() {
let bytes = if !fetch_image_data_as_well {
None
} else {
Some(image.bytes.clone())
};
Some((image_info, bytes))
} else if !fetch_image_data_as_well {
let mut webrender_image_cache = self.shared
.webrender_image_cache
.write()
.unwrap();
webrender_image_cache.insert(((*url).clone(), use_placeholder),
image_info);
Some((image_info, None))
} else {
Some((image_info, Some(image.bytes.clone())))
}
}
None | Some(ImageOrMetadataAvailable::MetadataAvailable(_)) => None,
}
}
}