browser: update urls after redirection

[krichprollsch]

$ zig build run -- fetch  http://www.urlfilterdb.com/
debug(cli): Fetch mode: url http://www.urlfilterdb.com/, dump false
debug(browser): start js env
debug(browser): setup global env
debug(polyfill): load polyfill-fetch: undefined
debug(browser): inspector context created
debug: Inspector contextCreated called
debug(browser): starting GET http://www.urlfilterdb.com/
info(http_client): redirecting to: GET https://www.urlfilterdb.com/
info(browser): GET https://www.urlfilterdb.com/ 200
debug(browser): header content-type: text/html; charset=utf-8
debug(browser): parse html with charset utf-8
debug(browser): inspector context created
debug: Inspector contextCreated called
debug(browser): wait: OK

[karlseguin]

We can treat the allocator like an ArenaAllocator or like an std.mem.Allocator.

If we treat it like an Arena, we can remove unnecessary frees, which has a super-tiny performance cost.

If we treat it like an Allocator, we gain some flexibility with respect to changing the implementation.

It isn't a system-wide decisions, there are places where we'll have an arena and want to treat it like a generic allocator, and there are places where we'll definitely want to take advantage of the arena's behavior. The reason I like to call these ArenaAllocators arena is that it's clear to the writer & reader what the behavior is.

TL;DR - The deinit is almost certainly a no-op and could be removed. It's up to you.

[karlseguin]

Does nothing

[karlseguin]

I see that you re-use the buffer later, which I guess is why you copy the contents. But, toOwnedSlice frees the underlying memory, so the underlying slice won't get re-used. I think you can use buf.items to avoid the allocation + copy.

[karlseguin]

As-above, if you stick with the toOwnedSlice(arena), then this code does nothing. toOwnedSlice(arena) calls clearAndFree().

If, above, you decide to do instead:

self.rawuri = buf.items

Then here you'll want to reset the buffer:

buf = .{};

as the clearRetainingCapacity() will break self.rawuri

[karlseguin]

Also the option to use buf.items here.

[krichprollsch]

@karlseguin thanks! I fixed the buffer usage.