The Servo Browser Engine
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Andrei Volykhin 8d086b9fe5
htmlmediaelement: Fix fetch request race on "seek-data" event (#37002)
On execution media element load algorithm

https://html.spec.whatwg.org/multipage/media.html#media-element-load-algorithm
we can observe race condition between parallel running fetch requests:
R1: (media element) initial request (see "resource_fetch_algorithm"
function)
R2: (gstreamer) duration "seek-data" request (see PlayerEvent::SeekData)
 R3: (gstreamer) continue on last interrupted time "seek-data" request

At time there are only one current fetch context for media element but
because resource fetch and cancellation are async operations need
to identify (by request id) and skip processing outdated fetch request
(fetch listener callbacks).

Async load in background sequence (stream content length = 2757913):
```
R1 (seek-offset=0):          [------------------------------X]
R2 (seek-offset=2757866):          [---------Y]
                               AS-****-+++-AE
R3 (seek-offset=98304):                         [----------------Z]
                                             BS-****-+++BE

R1 (seek-offset=0):          [------X]
R2 (seek-offset=2757866):                [--------Y] (discarded data)
                                     AS-****---------+++-AE

- A*/B* performed seeks (*** seek lock, +++ flush buffer queue + reset EOS)
  (on Gstreamer streaming thread)
- X/Y/Z "end-of-stream" events from fetch requests
  (on Servo script thread)
```

All incoming input data from different requests are mixed and
pushed to active media player, plus abnormal behaviour due to
intermixed X/Y/Z "end-of-stream" events.

To handle it properly we will unblock seek lock on "seek-data" event
(on script thread) as soon as possible (GStreamer will be able
to flush buffer queue and reset EOS state) and introduce buffered data
source
to delay pushing input data/EOS event until media player will be
actually ready.

Testing: Improvements to the following tests:
-
/html/canvas/element/manual/imagebitmap/createImageBitmap-origin.sub.html
-
/html/semantics/embedded-content/the-canvas-element/security.pattern.fillStyle.sub.html

Fixes: https://github.com/servo/servo/issues/31931
Fixes: https://github.com/servo/servo/issues/36989

Signed-off-by: Andrei Volykhin <andrei.volykhin@gmail.com>
2025-06-02 19:39:38 +00:00
.cargo Move various reflector types and traits to script_bindings (#35279) 2025-02-04 06:58:08 +00:00
.github OHOS CI: Allow run.json to be overwritten in upload action. (#37083) 2025-05-23 02:17:41 +00:00
.vscode use ruff rather than flake8 for python code linting (#37045) 2025-05-24 14:19:47 +00:00
components htmlmediaelement: Fix fetch request race on "seek-data" event (#37002) 2025-06-02 19:39:38 +00:00
docs Update in-tree docs to point to the new book (#32743) 2024-07-09 15:42:00 +00:00
etc Use ruff to enforce python code formatting (#37117) 2025-05-26 11:54:43 +00:00
ports/servoshell Constellation can now optionally report memory usage when the page is loaded. (#37151) 2025-05-30 17:15:06 +00:00
python bootstrap: Add winget fallback (#32836) 2025-05-27 09:51:46 +00:00
resources Replace hsts preload list hashmap with an FST (#37015) 2025-05-20 04:26:55 +00:00
support Hitrace-bench will now report simple memory results to bencher.dev. (#37215) 2025-06-02 15:56:15 +00:00
tests htmlmediaelement: Fix fetch request race on "seek-data" event (#37002) 2025-06-02 19:39:38 +00:00
third_party imagebitmap: Make ImageBitmap serializable and transferable (#37101) 2025-05-23 20:40:25 +00:00
.clang-format Run test-tidy on Windows 2019-11-21 09:56:39 +01:00
.gitattributes openharmony: add servoshell for ohos (#33295) 2024-09-20 08:20:27 +00:00
.gitignore Add Zed configuration files to .gitignore (#36909) 2025-05-08 08:23:19 +00:00
.mailmap Update Tetsuharu OHZEKI's entry in mailmap 2019-11-15 00:46:45 +09:00
.python-version Set python version to 3.11 (#34707) 2024-12-19 18:42:36 +00:00
Cargo.lock build(deps): bump prettyplease from 0.2.32 to 0.2.33 (#37221) 2025-06-02 18:13:18 +00:00
Cargo.toml build(deps): bump num_cpus from 1.16.0 to 1.17.0 (#37219) 2025-06-02 17:58:25 +00:00
CLOBBER
CODE_OF_CONDUCT.md Clarify the Code of Conduct (closes servo/servo.org#164) (#32835) 2024-07-23 09:12:03 +00:00
CONTRIBUTING.md Update in-tree docs to point to the new book (#32743) 2024-07-09 15:42:00 +00:00
deny.toml deps: Upgrade font-kit and dirs (#37163) 2025-05-28 11:57:23 +00:00
Info.plist
LICENSE
LICENSE_WHATWG_SPECS Add license for WHATWG specifications in code (#36282) 2025-04-03 04:33:06 +00:00
mach Fix mach argument quoting on NixOS (#35573) 2025-02-21 08:21:50 +00:00
mach.bat mach: adopt uv and avoid system python (#34632) 2024-12-16 09:20:37 +00:00
PULL_REQUEST_TEMPLATE.md Use a simpler GitHub pull request template (#36203) 2025-03-30 10:14:13 +00:00
README.md Link to the Zulip and project repo in README (#37134) 2025-05-26 15:51:50 +00:00
ruff.toml use ruff rather than flake8 for python code linting (#37045) 2025-05-24 14:19:47 +00:00
rust-toolchain.toml Unsimplify rust-toolchain.toml by adding clippy and rustfmt (#37028) 2025-05-16 17:04:27 +00:00
rustfmt.toml Update rustfmt to the 2024 style edition (#35764) 2025-03-03 11:26:53 +00:00
SECURITY.md docs(security): avoid possible misconception in the security policy (#37032) 2025-05-16 21:27:42 +00:00
servo-tidy.toml Implement basics of link preloading (#37036) 2025-05-29 11:26:27 +00:00
servobuild.example Remove some references to layout 2013 vs layout 2020 (#37007) 2025-05-14 19:53:48 +00:00
shell.nix Install tshark for automated tests in #36033 (#36201) 2025-03-28 09:43:03 +00:00
taplo.toml Format toml files (#30112) 2023-08-17 15:07:43 +00:00
uv.toml uv: Use native-tls (#36564) 2025-04-16 11:47:49 +00:00

The Servo Parallel Browser Engine Project

Servo is a prototype web browser engine written in the Rust language. It is currently developed on 64-bit macOS, 64-bit Linux, 64-bit Windows, 64-bit OpenHarmony, and Android.

Servo welcomes contribution from everyone. Check out:

Coordination of Servo development happens:

Getting started

For more detailed build instructions, see the Servo book under Setting up your environment, Building Servo, Building for Android and Building for OpenHarmony.

macOS

  • Download and install Xcode and brew.
  • Install uv: curl -LsSf https://astral.sh/uv/install.sh | sh
  • Install rustup: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
  • Restart your shell to make sure cargo is available
  • Install the other dependencies: ./mach bootstrap
  • Build servoshell: ./mach build

Linux

  • Install curl:
    • Arch: sudo pacman -S --needed curl
    • Debian, Ubuntu: sudo apt install curl
    • Fedora: sudo dnf install curl
    • Gentoo: sudo emerge net-misc/curl
  • Install uv: curl -LsSf https://astral.sh/uv/install.sh | sh
  • Install rustup: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
  • Restart your shell to make sure cargo is available
  • Install the other dependencies: ./mach bootstrap
  • Build servoshell: ./mach build

Windows

  • Download uv, choco, and rustup
    • Be sure to select Quick install via the Visual Studio Community installer
  • In the Visual Studio Installer, ensure the following components are installed:
    • Windows 10 SDK (10.0.19041.0) (Microsoft.VisualStudio.Component.Windows10SDK.19041)
    • MSVC v143 - VS 2022 C++ x64/x86 build tools (Latest) (Microsoft.VisualStudio.Component.VC.Tools.x86.x64)
    • C++ ATL for latest v143 build tools (x86 & x64) (Microsoft.VisualStudio.Component.VC.ATL)
    • C++ MFC for latest v143 build tools (x86 & x64) (Microsoft.VisualStudio.Component.VC.ATLMFC)
  • Restart your shell to make sure cargo is available
  • Install the other dependencies: .\mach bootstrap
  • Build servoshell: .\mach build

Android

  • Ensure that the following environment variables are set:
    • ANDROID_SDK_ROOT
    • ANDROID_NDK_ROOT: $ANDROID_SDK_ROOT/ndk/26.2.11394342/ ANDROID_SDK_ROOT can be any directory (such as ~/android-sdk). All of the Android build dependencies will be installed there.
  • Install the latest version of the Android command-line tools to $ANDROID_SDK_ROOT/cmdline-tools/latest.
  • Run the following command to install the necessary components:
    sudo $ANDROID_SDK_ROOT/cmdline-tools/latest/bin/sdkmanager --install \
     "build-tools;34.0.0" \
     "emulator" \
     "ndk;26.2.11394342" \
     "platform-tools" \
     "platforms;android-33" \
     "system-images;android-33;google_apis;x86_64"
    
  • Follow the instructions above for the platform you are building on

OpenHarmony

  • Follow the instructions above for the platform you are building on to prepare the environment.
  • Depending on the target distribution (e.g. HarmonyOS NEXT vs pure OpenHarmony) the build configuration will differ slightly.
  • Ensure that the following environment variables are set
    • DEVECO_SDK_HOME (Required when targeting HarmonyOS NEXT)
    • OHOS_BASE_SDK_HOME (Required when targeting OpenHarmony)
    • OHOS_SDK_NATIVE (e.g. ${DEVECO_SDK_HOME}/default/openharmony/native or ${OHOS_BASE_SDK_HOME}/${API_VERSION}/native)
    • SERVO_OHOS_SIGNING_CONFIG: Path to json file containing a valid signing configuration for the demo app.
  • Review the detailed instructions at Building for OpenHarmony.
  • The target distribution can be modified by passing --flavor=<default|harmonyos> to `mach <build|package|install>.