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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/. */
use crate::FetchResponseMsg;
use crate::image::base::{Image, ImageMetadata};
use ipc_channel::ipc::IpcSender;
use servo_url::ServoUrl;
use std::sync::Arc;
use webrender_api;
// ======================================================================
// Aux structs and enums.
// ======================================================================
/// Whether a consumer is in a position to request images or not. This can occur
/// when animations are being processed by the layout thread while the script
/// thread is executing in parallel.
#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
pub enum CanRequestImages {
No,
Yes,
}
/// Indicating either entire image or just metadata availability
#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
pub enum ImageOrMetadataAvailable {
ImageAvailable(#[ignore_malloc_size_of = "Arc"] Arc<Image>, ServoUrl),
MetadataAvailable(ImageMetadata),
}
/// This is optionally passed to the image cache when requesting
/// and image, and returned to the specified event loop when the
/// image load completes. It is typically used to trigger a reflow
/// and/or repaint.
#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct ImageResponder {
id: PendingImageId,
sender: IpcSender<PendingImageResponse>,
}
impl ImageResponder {
pub fn new(sender: IpcSender<PendingImageResponse>, id: PendingImageId) -> ImageResponder {
ImageResponder {
sender: sender,
id: id,
}
}
pub fn respond(&self, response: ImageResponse) {
debug!("Notifying listener");
// This send can fail if thread waiting for this notification has panicked.
// That's not a case that's worth warning about.
// TODO(#15501): are there cases in which we should perform cleanup?
let _ = self.sender.send(PendingImageResponse {
response: response,
id: self.id,
});
}
}
/// The returned image.
#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
pub enum ImageResponse {
/// The requested image was loaded.
Loaded(#[ignore_malloc_size_of = "Arc"] Arc<Image>, ServoUrl),
/// The request image metadata was loaded.
MetadataLoaded(ImageMetadata),
/// The requested image failed to load, so a placeholder was loaded instead.
PlaceholderLoaded(#[ignore_malloc_size_of = "Arc"] Arc<Image>, ServoUrl),
/// Neither the requested image nor the placeholder could be loaded.
None,
}
/// The current state of an image in the cache.
#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
pub enum ImageState {
Pending(PendingImageId),
LoadError,
NotRequested(PendingImageId),
}
/// The unique id for an image that has previously been requested.
#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize)]
pub struct PendingImageId(pub u64);
#[derive(Debug, Deserialize, Serialize)]
pub struct PendingImageResponse {
pub response: ImageResponse,
pub id: PendingImageId,
}
#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
pub enum UsePlaceholder {
No,
Yes,
}
// ======================================================================
// ImageCache public API.
// ======================================================================
pub trait ImageCache: Sync + Send {
fn new(webrender_api: webrender_api::RenderApi) -> Self
where
Self: Sized;
/// Return any available metadata or image for the given URL,
/// or an indication that the image is not yet available if it is in progress,
/// or else reserve a slot in the cache for the URL if the consumer can request images.
fn find_image_or_metadata(
&self,
url: ServoUrl,
use_placeholder: UsePlaceholder,
can_request: CanRequestImages,
) -> Result<ImageOrMetadataAvailable, ImageState>;
/// Add a new listener for the given pending image id. If the image is already present,
/// the responder will still receive the expected response.
fn add_listener(&self, id: PendingImageId, listener: ImageResponder);
/// Inform the image cache about a response for a pending request.
fn notify_pending_response(&self, id: PendingImageId, action: FetchResponseMsg);
/// Ensure an image has a webrender key.
fn set_webrender_image_key(&self, image: &mut Image);
}
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