[Buildroot] [PATCH 02/16 v5] core/pkg-utils: add macro to hardlink-or-copy

[Arnout Vandecappelle <arnout@mind.be>]

On 03/19/16 15:23, Thomas Petazzoni wrote:
> Dear Yann E. MORIN,
>
> On Fri, 11 Mar 2016 18:49:15 +0100, Yann E. MORIN wrote:
>
>> +################################################################################
>> +# hardlink-copy -- hardlink source and destination if possible, otherwise
>> +# do a simple copy
>> +#
>> +# argument 1 is the source *file*
>> +# argument 2 is the destination *directory*
>> +# argument 3 is the basename of the destination file (optional, defaults to
>> +#            the basename of the source file.
>> +#
>> +# examples:
>> +#   $(call hardlink-copy,/path/to/source/file,/path/to/destination/dir)
>> +#   $(call hardlink-copy,/path/to/source/file,/path/to/destination/dir,new-name)
>> +#
>> +# Notes:
>> +#  - this is NOT an atomic operation,
>> +#  - this is only a wrapper to a shell script, so that it can be used with
>> +#    shell-level variables, like in a for loop.
>> +################################################################################
>> +define hardlink-copy
>> +	support/scripts/hardlink-copy "$(strip $(1))" "$(strip $(2))" "$(strip $(3))"
>> +endef
>
> While in certain cases, I agree that a shell wrapper is nice and
> useful, here I really don't see the point of a shell wrapper. You can
> simply do (untested):
>
> define hardlink-or-copy-inner
> 	rm -f $(2)
> 	ln -f $(1) $(2) 2>/dev/null || cp -f $(1) $(2)
> endef
>
> define hardlink-or-copy
> 	$(call hardlink-or-copy-inner,$(1),$(if $(3),$(2)/$(3),$(2)/$(basename $(1))))
> endef

  I disagree. This may be slightly shorter in lines of code, but I think the 
shell script is much more readable.

  However, I do wonder if it makes sense to have a make function for it if there 
already is a shell script. We don't do that for apply-patches, so why would we 
do it for this one?

>
> Note that I think the name of the macro should be hardlink-or-copy and
> not hardlink-copy. The name hardlink-copy seems to indicate that you
> are copying a hardlink, which is not what is happening.
> hardlink-or-copy is IMO clearer on the fact that the macro does a hardlink
> or a copy.

  I agree with that.

  Regards,
  Arnout

>
> Thanks!
>
> Thomas
>


-- 
Arnout Vandecappelle                          arnout at mind be
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