[Buildroot] [PATCH 03/16 v3] core/pkg-utils: add macro to hardlink-or-copy

[Arnout Vandecappelle <arnout@mind.be>]

On 28-01-16 19:15, Yann E. MORIN wrote:
> This macro will try to copy a source file into a destination fdirectory,
> by first atempting a hard-link, and falling back to a plain copy.
> 
> In some situations, it will be necessary that the destination file is
> named differently than the source (e.g. due to a re-numbering), so if a
> third argument is specified, it is treated as the basename of the
> destination file.
> 
> Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Cc: Luca Ceresoli <luca@lucaceresoli.net>
> 
> ---
> Changes v2 -> v3;
>   - use "ln" instead of "cp -l"
>   - accept third argument, as the basename of the destination file
>   - drop reviewed-by and tested-by tags given in v2, due to the above
>     two changes
> 
> Changes RFC -> v1:
>   - move to pkg-utils  (Luca)
> ---
>  package/pkg-utils.mk | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/package/pkg-utils.mk b/package/pkg-utils.mk
> index 44bd2c9..6479cd8 100644
> --- a/package/pkg-utils.mk
> +++ b/package/pkg-utils.mk
> @@ -113,6 +113,31 @@ $$(error Package error: use $(2) instead of $(1). Please fix your .mk file)
>  endif
>  endef
>  
> +################################################################################
> +# 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/)
> +#   $(call hardlink-copy,/path/to/source/file,/path/to/destination/dir/,new-name)
> +#
> +# Note: we make that a single command, so se can:
> +#  - use '$(Q)' in front of it and properly silence the whole macro,
> +#  - use '|| exit 1' after it, so we can exit on error in compound commands.
> +################################################################################
> +define hardlink-copy
> +	{ mkdir -p $(2) && \
> +		{ ln $(1) $(2)$(if $(3),/$(strip $(3))) 2>/dev/null || \

 Shouldn't this be ln -f (and maybe cp -f) to make sure it behaves the same when
you run it a second time?


 Regards,
 Arnout

> +		  cp $(1) $(2)$(if $(3),/$(strip $(3))); \
> +		} \
> +	}
> +endef
> +
>  #
>  # legal-info helper functions
>  #
> 


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
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