Lightpanda migrate DOM implementation to Zig
lightpanda.io
Lightpanda migrate DOM implementation to Zig
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Re: Lightpanda migrate DOM implementation to Zig
#2This reminds me of the Servo project's journey. Always impressed to see another implementation of the WHATWG specs.
It's interesting to see Zig being chosen here over Rust for a browser engine component. Rust has kind of become the default answer for "safe browser components" (e.g., Servo, Firefox's oxidation), primarily because the borrow checker maps so well to the ownership model of a DOM tree in theory. But in practice, DOM nodes often need shared mutable state (parent pointers, child pointers, event listeners), which forces you into Rc> hell in Rust.
Zig's manual memory management might actually be more ergonomic for a DOM implementation specifically because you can model the graph relationships more directly without fighting the compiler, provided you have a robust strategy for the arena allocation. Excited to learn from Lightpanda's implementation when it's out.
Re: Lightpanda migrate DOM implementation to Zig
#3This reminds me of the Servo project's journey. Always impressed to see another implementation of the WHATWG specs. It's interesting to see Zig being chosen here over Rust for a browser engine component. Rust has kind of become the default answer for "safe browser components" (e.g., Servo, Firefox's oxidation), primarily because the borrow checker maps so well to the ownership model of a DOM tree in theory. But in pr…
Hi, I am Francis, founder of Lightpanda. We wrote a full article explaining why we choose Zig over Rust or C++, if you are interested: https://lightpanda.io/blog/posts/why-we-built-lightpanda-in-...
Our goal is to build a headless browser, rather than a general purpose browser like Servo or Chrome. It's already available if you would like to try it: https://lightpanda.io/docs/open-source/installation
Re: Lightpanda migrate DOM implementation to Zig
#4This reminds me of the Servo project's journey. Always impressed to see another implementation of the WHATWG specs. It's interesting to see Zig being chosen here over Rust for a browser engine component. Rust has kind of become the default answer for "safe browser components" (e.g., Servo, Firefox's oxidation), primarily because the borrow checker maps so well to the ownership model of a DOM tree in theory. But in pr…
And use-after-free, when that arena's memory goes away.
Re: Lightpanda migrate DOM implementation to Zig
#5This reminds me of the Servo project's journey. Always impressed to see another implementation of the WHATWG specs. It's interesting to see Zig being chosen here over Rust for a browser engine component. Rust has kind of become the default answer for "safe browser components" (e.g., Servo, Firefox's oxidation), primarily because the borrow checker maps so well to the ownership model of a DOM tree in theory. But in pr…
Hi, I am Francis, founder of Lightpanda. We wrote a full article explaining why we choose Zig over Rust or C++, if you are interested: https://lightpanda.io/blog/posts/why-we-built-lightpanda-in-... Our goal is to build a headless browser, rather than a general purpose browser like Servo or Chrome. It's already available if you would like to try it: https://lightpanda.io/docs/open-source/installation
Thanks Francis, appreciate the nice & honest write-up with the thought process (while keeping it brief).
Re: Lightpanda migrate DOM implementation to Zig
#6This reminds me of the Servo project's journey. Always impressed to see another implementation of the WHATWG specs. It's interesting to see Zig being chosen here over Rust for a browser engine component. Rust has kind of become the default answer for "safe browser components" (e.g., Servo, Firefox's oxidation), primarily because the borrow checker maps so well to the ownership model of a DOM tree in theory. But in pr…
Hi, I am Francis, founder of Lightpanda. We wrote a full article explaining why we choose Zig over Rust or C++, if you are interested: https://lightpanda.io/blog/posts/why-we-built-lightpanda-in-... Our goal is to build a headless browser, rather than a general purpose browser like Servo or Chrome. It's already available if you would like to try it: https://lightpanda.io/docs/open-source/installation
Off topic note: I read the website and a few pages of the docs and it's unclear to me for what I can use LightPanda safely. Like say I wanted to swap my it as my engine on playwright, what are the tradeoffs? What things are implemented, what isnt?
Re: Lightpanda migrate DOM implementation to Zig
#7This table is informative as to exactly what lightpanda is: https://lightpanda.io/blog/posts/what-is-a-true-headless-bro...
TL;DR: It does the following:
- Fetch HTML over the network
- Parse HTML into a DOM tree
- Fetch and execute JavaScript that manipulates the DOM
But not the following:
- Fetch and parse CSS to apply styling rules
- Calculate layout
- Fetch images and fonts for display
- Paint pixels to render the visual result
- Composite layers for smooth scrolling and animations
So it's effectively a net+DOM+script-only browser with no style/layout/paint.
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Definitely fun for me to watch as someone who is making a lightweight browser engine with a different set of trade-offs (net+DOM+style/layout/paint-only with no script)
Re: Lightpanda migrate DOM implementation to Zig
#8This table is informative as to exactly what lightpanda is: https://lightpanda.io/blog/posts/what-is-a-true-headless-bro... TL;DR: It does the following: - Fetch HTML over the network - Parse HTML into a DOM tree - Fetch and execute JavaScript that manipulates the DOM But not the following: - Fetch and parse CSS to apply styling rules - Calculate layout - Fetch images and fonts for display - Paint pixels to render th…
When I was working before on something that used headless browser agents, the ability to do a screenshot (or even a recording) was really great for debugging... so I am not sure about the "no paint". But hey everything in life is a trade-off.
Re: Lightpanda migrate DOM implementation to Zig
#9Earlier quoted context omitted.
Hi, I am Francis, founder of Lightpanda. We wrote a full article explaining why we choose Zig over Rust or C++, if you are interested: https://lightpanda.io/blog/posts/why-we-built-lightpanda-in-... Our goal is to build a headless browser, rather than a general purpose browser like Servo or Chrome. It's already available if you would like to try it: https://lightpanda.io/docs/open-source/installation
Off topic note: I read the website and a few pages of the docs and it's unclear to me for what I can use LightPanda safely. Like say I wanted to swap my it as my engine on playwright, what are the tradeoffs? What things are implemented, what isnt?
I think it's really more of an alternative to JSDom than it is an alternative to Chromium. It's not going to fool any websites that care about bots into thinking it's a real browser in other words.
Re: Lightpanda migrate DOM implementation to Zig
#10This reminds me of the Servo project's journey. Always impressed to see another implementation of the WHATWG specs. It's interesting to see Zig being chosen here over Rust for a browser engine component. Rust has kind of become the default answer for "safe browser components" (e.g., Servo, Firefox's oxidation), primarily because the borrow checker maps so well to the ownership model of a DOM tree in theory. But in pr…
I don't think it's really that bad in Rust. If you're happy with an arena in Zig you can do exactly the same thing in Rust. There are a ton of options listed here: https://donsz.nl/blog/arenas/
Some of them even prevent use after free (the "ABA mitigation" column).