WebKit with patches

This is a build of WebKit with some extra patches used by bun

The changes to WebKit are as follows:

• bmalloc::api::availableMemory() accounts for cgroups 1 & 2 memory limits
• JSC::ErrorInstance has a captureStackTrace function which lets you update the internally-stored Vector<StackTrace>
• JSC::JSGlobalObject has a double overridenDateNow field which lets you override the timestamp used for Date.now() and new Date()
• JSC::VM has a onComputeErrorInfo callback which lets the embedder customize how Error.prototype.stack strings are formatted (Bun uses this to make them match V8's behavior, for Node.js compatibility)
• More things are exported
• Typed Arrays can be passed through DOMJIT
• ExternalStringImpl has an extra pointer field
• OptionsList::showPrivateScriptsInStackTraces() enables ImplementationVisibilty::Private functions showing up in stack traces
• Many of the locks in the C API are removed. Locking is handled internally by the bundler.
• JSString iterator that exposes the pointer of each nested JSRopeString's underlying buffer to a callback without flattening/allocating an entirely new string. This is useful for native code piping strings from JavaScript to elsewhere, or manually allocating strings outside of WTF::String. console.log or server-side rendering (when not using streams) are examples.
• ExternalStringImpl now supports static strings. This is somewhat of a hack; the better solution for this case is a script that generates all the static strings at compile time using NeverDestroyed<StaticStringImpl>, however need to figure out a way to do that well from Zig.
• OptionsList::useV8DateParser enables v8's date parser.
• The ReferenceError message was changed to match V8 (ReferenceError: Can't find variable: <variable> -> ReferenceError: <variable> is undefined).

Still need to figure out how to get the remote inspector to work.

NOTE: If you make a change to this repo make sure to update the commit hash in cmake/tools/SetupWebKit.cmake in Bun.

---

WebKit

WebKit is a cross-platform web browser engine. On iOS and macOS, it powers Safari, Mail, Apple Books, and many other applications. For more information about WebKit, see the WebKit project website.

Trying the Latest

On macOS, download Safari Technology Preview to test the latest version of WebKit. On Linux, download Epiphany Technology Preview. On Windows, you'll have to build it yourself.

Reporting Bugs

1. Search WebKit Bugzilla to see if there is an existing report for the bug you've encountered.
2. Create a Bugzilla account to report bugs (and comment on them) if you haven't done so already.
3. File a bug in accordance with our guidelines.

Once your bug is filed, you will receive email when it is updated at each stage in the bug life cycle. After the bug is considered fixed, you may be asked to download the latest nightly and confirm that the fix works for you.

Getting the Code

Run the following command to clone WebKit's Git repository:

git clone https://github.com/WebKit/WebKit.git WebKit

You can enable git fsmonitor to make many git commands faster (such as git status) with git config core.fsmonitor true

Building WebKit

Building for Apple platforms

Install Xcode and its command line tools if you haven't done so already:

1. Install Xcode
2. Install the Xcode Command Line Tools In Terminal, run the command: xcode-select --install
3. Install the Metal toolchain In Terminal, run the command: xcodebuild -downloadComponent MetalToolchain

Run the following command to build a macOS debug build with debugging symbols and assertions:

Tools/Scripts/build-webkit --debug

For performance testing, and other purposes, use --release instead. If you also need debug symbols (dSYMs), run:

Tools/Scripts/build-webkit --release DEBUG_INFORMATION_FORMAT=dwarf-with-dsym 

Embedded Builds

To build for an embedded platform like iOS, tvOS, or watchOS, pass a platform argument to build-webkit.

For example, to build a debug build with debugging symbols and assertions for embedded simulators:

Tools/Scripts/build-webkit --debug --<platform>-simulator

or embedded devices:

Tools/Scripts/build-webkit --debug --<platform>-device

where platform is ios, tvos or watchos.

Using Xcode

You can open WebKit.xcworkspace to build and debug WebKit within Xcode. Select the "Everything up to WebKit + Tools" scheme to build the entire project.

If you don't use a custom build location in Xcode preferences, you have to update the workspace settings to use WebKitBuild directory. In menu bar, choose File > Workspace Settings, then click the Advanced button, select "Custom", "Relative to Workspace", and enter WebKitBuild for both Products and Intermediates.

Building the GTK Port

For production builds:

cmake -DPORT=GTK -DCMAKE_BUILD_TYPE=RelWithDebInfo -GNinja
ninja
sudo ninja install

For development builds:

Tools/gtk/install-dependencies
Tools/Scripts/update-webkitgtk-libs
Tools/Scripts/build-webkit --gtk --debug

For more information on building WebKitGTK, see the wiki page.

Building the WPE Port

For production builds:

cmake -DPORT=WPE -DCMAKE_BUILD_TYPE=RelWithDebInfo -GNinja
ninja
sudo ninja install

For development builds:

Tools/wpe/install-dependencies
Tools/Scripts/update-webkitwpe-libs
Tools/Scripts/build-webkit --wpe --debug

Building Windows Port

For building WebKit on Windows, see the WebKit on Windows page.

Running WebKit

With Safari and Other macOS Applications

Run the following command to launch Safari with your local build of WebKit:

Tools/Scripts/run-safari --debug

The run-safari script sets the DYLD_FRAMEWORK_PATH environment variable to point to your build products, and then launches /Applications/Safari.app. DYLD_FRAMEWORK_PATH tells the system loader to prefer your build products over the frameworks installed in /System/Library/Frameworks.

To run other applications with your local build of WebKit, run the following command:

Tools/Scripts/run-webkit-app <application-path>

iOS Simulator

Run the following command to launch iOS simulator with your local build of WebKit:

run-safari --debug --ios-simulator

In both cases, if you have built release builds instead, use --release instead of --debug.

To run other applications, for example MobileMiniBrowser, with your local build of WebKit, run the following command:

Tools/Scripts/run-webkit-app --debug --iphone-simulator <application-path>

Using Xcode

Open WebKit.xcworkspace, select intended scheme such as MobileMiniBrowser and an iOS simulator as target, click run.

Linux Ports

If you have a development build, you can use the run-minibrowser script, e.g.:

run-minibrowser --debug --wpe

Pass one of --gtk, --jsc-only, or --wpe to indicate the port to use.

Contribute

Congratulations! You’re up and running. Now you can begin coding in WebKit and contribute your fixes and new features to the project. For details on submitting your code to the project, read Contributing Code.