> allocChunk is an approach that enables users to customise their own allocator
> types.
Are you sure this is necessary ? From my experience, the people who needs a
custom allocator knows how to implement it and the people who don't know how to
implement an allocator shouldn't touch that stuff anyway.
There are very little use-case where you need a custom allocator.
Plus, you're using dynamic dispatch when your memory allocator should
certainly be fixed at compile-time. So, If you really want to do that, I would
just use static dispatch or a compile-time switch and not bother with
inheritance
import std/streams
type
Chunk = ref object
ChunkAllocator = ref ChunkAllocatorObj
ChunkAllocatorObj = object
MyStream = ref object of StreamObj
al: ChunkAllocator
proc allocChunk*(al: ChunkAllocator): Chunk {.base, raises: [], gcsafe.} =
# RootEffect
when not defined(MyStreamCustomAllocator):
# doNormalAlloc(al)
discard
else:
customAllocChunk(al) # user is expected to have implemented this
function
proc writeDataImpl(s: Stream, buffer: pointer, bufLen: int) =
let s = MyStream(s)
discard s.al.allocChunk()
proc newMyStream(al: ChunkAllocator): MyStream =
new (result)
result.writeDataImpl = writeDataImpl
Run
