This looks like extremely brittle code to my eyes. Look at
https://github.com/wilsonzlin/fastrender/blob/main/crates/fa...What is `FrameState::render_placeholder`?
```
pub fn render_placeholder(&self, frame_id: FrameId) -> Result {
let (width, height) = self.viewport_css;
let len = (width as usize)
.checked_mul(height as usize)
.and_then(|px| px.checked_mul(4))
.ok_or_else(|| "viewport size overflow".to_string())?;
if len > MAX_FRAME_BYTES {
return Err(format!(
"requested frame buffer too large: {width}x{height} => {len} bytes"
));
}
// Deterministic per-frame fill color to help catch cross-talk in tests/debugging.
let id = frame_id.0;
let url_hash = match self.navigation.as_ref() {
Some(IframeNavigation::Url(url)) => Self::url_hash(url),
Some(IframeNavigation::AboutBlank) => Self::url_hash("about:blank"),
Some(IframeNavigation::Srcdoc { content_hash }) => {
let folded = (*content_hash as u32) ^ ((*content_hash >> 32) as u32);
Self::url_hash("about:srcdoc") ^ folded
}
None => 0,
};
let r = (id as u8) ^ (url_hash as u8);
let g = ((id >> 8) as u8) ^ ((url_hash >> 8) as u8);
let b = ((id >> 16) as u8) ^ ((url_hash >> 16) as u8);
let a = 0xFF;
let mut rgba8 = vec![0u8; len];
for px in rgba8.chunks_exact_mut(4) {
px[0] = r;
px[1] = g;
px[2] = b;
px[3] = a;
}
Ok(FrameBuffer {
width,
height,
rgba8,
})
}
}
```
What is it doing in these diffs?
https://github.com/wilsonzlin/fastrender/commit/f4a0974594e3...
I'd be really curious to see the amount of work/rework over time, and the token/time cost for each additional actual completed test case.