Re: [PATCH v3 4/4] convert: add "status=delayed" to filter process protocol

[Lars Schneider <larsxschneider@gmail.com>]

> On 09 Apr 2017, at 21:11, Lars Schneider <larsxschneider@gmail.com> wrote:
> 
> Some `clean` / `smudge` filters might require a significant amount of
> time to process a single blob. During this process the Git checkout
> operation is blocked and Git needs to wait until the filter is done to
> continue with the checkout.
> 
> Teach the filter process protocol (introduced in edcc858) to accept the
> status "delayed" as response to a filter request. Upon this response Git
> continues with the checkout operation. After the checkout operation Git
> calls "finish_delayed_checkout" which queries the filter for remaining
> blobs. If the filter is still working on the completion, then the filter
> is expected to block. If the filter has completed all remaining blobs
> then an empty response is expected.
> 
> Git has a multiple code paths that checkout a blob. Support delayed
> checkouts only in `clone` (in unpack-trees.c) and `checkout` operations.
> 
> Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
> ---
> ...
> diff --git a/convert.h b/convert.h
> index 82871a11d5..da6c702090 100644
> --- a/convert.h
> +++ b/convert.h
> @@ -42,6 +42,11 @@ extern int convert_to_git(const char *path, const char *src, size_t len,
> 			  struct strbuf *dst, enum safe_crlf checksafe);
> extern int convert_to_working_tree(const char *path, const char *src,
> 				   size_t len, struct strbuf *dst);
> +extern int async_convert_to_working_tree(const char *path, const char *src,
> +					 size_t len, struct strbuf *dst,
> +					 void *dco);
> 

I don't like the void pointer here. However, "cache.h" includes "convert.h" and
therefore "convert.h" cannot include "cache.h". That's why "convert.h" doesn't
know about "struct delayed_checkout". 

I just realized that I could move "struct delayed_checkout" and "enum ce_delay_state"
definition from "cache.h" to "convert.h" to solve the problem nicely.

Any objection to this approach?

Thanks,
Lars