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Use separate IPC-only locking mechanism when locking from webxr

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Manishearth committed Jul 11, 2019
1 parent 036b495 commit c5a0fc56ea5260a7dcd811abc76d2f51e2ad2fb6
Showing with 25 additions and 7 deletions.
  1. +20 −4 components/canvas/webgl_thread.rs
  2. +5 −3 components/canvas_traits/webgl.rs
@@ -9,6 +9,7 @@ use euclid::Size2D;
use fnv::FnvHashMap;
use gleam::gl;
use half::f16;
use ipc_channel::ipc::IpcSender;
use offscreen_gl_context::{DrawBuffer, GLContext, NativeGLContextMethods};
use pixels::{self, PixelFormat};
use std::borrow::Cow;
@@ -181,6 +182,9 @@ impl<VR: WebVRRenderHandler + 'static> WebGLThread<VR> {
WebGLMsg::Lock(ctx_id, sender) => {
self.handle_lock(ctx_id, sender);
},
WebGLMsg::LockIPC(ctx_id, sender) => {
self.handle_lock_ipc(ctx_id, sender);
},
WebGLMsg::Unlock(ctx_id) => {
self.handle_unlock(ctx_id);
},
@@ -231,13 +235,27 @@ impl<VR: WebVRRenderHandler + 'static> WebGLThread<VR> {
);
}
}

/// Handles a lock external callback received from webrender::ExternalImageHandler
fn handle_lock(
&mut self,
context_id: WebGLContextId,
sender: WebGLSender<(u32, Size2D<i32>, usize)>,
) {
sender.send(self.handle_lock_inner(context_id)).unwrap();
}

/// handle_lock, but unconditionally IPC (used by webxr)
fn handle_lock_ipc(
&mut self,
context_id: WebGLContextId,
sender: IpcSender<(u32, Size2D<i32>, usize)>,
) {
sender.send(self.handle_lock_inner(context_id)).unwrap();
}

/// Shared code between handle_lock and handle_lock_ipc, does the actual syncing/flushing
/// but the caller must send the response back
fn handle_lock_inner(&mut self, context_id: WebGLContextId) -> (u32, Size2D<i32>, usize) {
let data =
Self::make_current_if_needed(context_id, &self.contexts, &mut self.bound_context_id)
.expect("WebGLContext not found in a WebGLMsg::Lock message");
@@ -251,9 +269,7 @@ impl<VR: WebVRRenderHandler + 'static> WebGLThread<VR> {
// Without proper flushing, the sync object may never be signaled.
data.ctx.gl().flush();

sender
.send((info.texture_id, info.size, gl_sync as usize))
.unwrap();
(info.texture_id, info.size, gl_sync as usize)
}

/// Handles an unlock external callback received from webrender::ExternalImageHandler
@@ -7,7 +7,7 @@ use gleam::gl;
use gleam::gl::GLsync;
use gleam::gl::GLuint;
use gleam::gl::Gl;
use ipc_channel::ipc::{IpcBytesReceiver, IpcBytesSender, IpcSender, IpcSharedMemory};
use ipc_channel::ipc::{self, IpcBytesReceiver, IpcBytesSender, IpcSender, IpcSharedMemory};
use pixels::PixelFormat;
use std::borrow::Cow;
use std::fmt;
@@ -61,6 +61,8 @@ pub enum WebGLMsg {
/// The WR client should not change the shared texture content until the Unlock call.
/// Currently OpenGL Sync Objects are used to implement the synchronization mechanism.
Lock(WebGLContextId, WebGLSender<(u32, Size2D<i32>, usize)>),
/// Lock(), but unconditionally IPC (used by webxr)
LockIPC(WebGLContextId, IpcSender<(u32, Size2D<i32>, usize)>),
/// Unlocks a specific WebGLContext. Unlock messages are used for a correct synchronization
/// with WebRender external image API.
/// The WR unlocks a context when it finished reading the shared texture contents.
@@ -195,9 +197,9 @@ struct SerializableWebGLMsgSender {
#[typetag::serde]
impl webxr_api::WebGLExternalImageApi for SerializableWebGLMsgSender {
fn lock(&self) -> Result<(GLuint, Size2D<i32>, GLsync), webxr_api::Error> {
let (sender, receiver) = webgl_channel().or(Err(webxr_api::Error::CommunicationError))?;
let (sender, receiver) = ipc::channel().or(Err(webxr_api::Error::CommunicationError))?;
self.sender
.send(WebGLMsg::Lock(self.ctx_id, sender))
.send(WebGLMsg::LockIPC(self.ctx_id, sender))
.or(Err(webxr_api::Error::CommunicationError))?;
let (texture, size, sync) = receiver
.recv()

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