Re: [PATCH 04/14] object-file: introduce function to iterate through objects

[Justin Tobler <jltobler@gmail.com>]

On 26/01/15 12:04PM, Patrick Steinhardt wrote:
> We have multiple divergent interfaces to iterate through objects of a
> specific backend:
> 
>   - `for_each_loose_object()` yields all loose objects.
> 
>   - `for_each_packed_object()` (somewhat obviously) yields all packed
>     objects.
> 
> These functions have different function signatures, which makes it hard
> to create a common abstraction layer that covers both of these.

I assume that the intention is to eventually have a generic
for_each_object() function that can iterate across objects regardless of
the source. Is the end goal to have each source define the appropriate
for_each_object callback?

> Introduce a new function `odb_source_loose_for_each_object()` to plug
> this gap. This function doesn't take any data specific to loose objects,
> but instead it accepts a `struct object_info` that will be populated the
> exact same as if `odb_source_loose_read_object()` was called.
> 
> The benefit of this new interface is that we can continue to pass
> backend-specific data, as `struct object_info` contains a union for
> these exact use cases. This will allow us to unify how we iterate
> through objects across both loose and packed objects in a subsequent
> commit.

Naive question: in a future where we have additional ODB backends, does
this mean that `struct object_info` would also need to be updated to
include them?

> The `for_each_loose_object()` function continues to exist for now, but
> it will be removed at the end of this patch series.