[U-Boot] [RFC PATCH v2] Makefile: search for GNU date

["Andreas Bießmann" <andreas.devel@googlemail.com>]

On 08/27/2015 03:03 PM, Paul Kocialkowski wrote:
> Le jeudi 27 ao?t 2015 ? 11:30 +0200, Andreas Bie?mann a ?crit :


>> Changes in v2:
>> * check for '-u' and '-d "@0"' switch rather than for the GNU variant
>>
>>  Makefile | 15 ++++++++++++---
>>  1 file changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/Makefile b/Makefile
>> index b9b2375..b797e38 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -346,6 +346,10 @@ PERL		= perl
>>  PYTHON		= python
>>  DTC		= dtc
>>  CHECK		= sparse
>> +DATE	       := $(foreach date,gdate date.gnu date, \
>> +		    $(shell _date=`which $(date)`; \
>> +		      $${_date} -u -d "@0" >/dev/null 2>&1; \
>> +		      test $$? -eq 0 && echo $${_date}))
> 
> First, I don't understand why you need to call date with the full path:
> if which can find it, then calling the binary without its full path
> should do just as well, right?

You'r right.

> Then, correct me if I'm wrong, but calling test and using && is
> overkill, you could simply do: $${_date} -u -d "@0" >/dev/null 2>&1 &&
> echo $${_date}

Also true.

> So in the end, the whole line would look like:
> 
> DATE	       := $(foreach date,gdate date.gnu date, \
> 		    $($${date} -u -d "@0" >/dev/null 2>&1 \
> 		      && echo $${date}))
> 
> Let me know what you think (and please test it as well).

That should work. I wonder however why we don't include this snippet in
the filechk_timestamp.h script directly. In fact the $(DATE) (a date
that support -d '@0' switch) is just used there, so why clobber the
Makefile with it?

---8<---
define filechk_timestamp.h
 (if test -n "$${SOURCE_DATE_EPOCH}"; then \
   date=""; \
   for _date in gdate date.gnu date; do \
   $${_date} -u -d "$${SOURCE_DATE}" >/dev/null 2>&1 && \
      date="$${_date}"; \
   done; \
   if test -n "$${date}"; then \
    SOURCE_DATE="@$${SOURCE_DATE_EPOCH}"; \
    LC_ALL=C $${date} -u -d "$${SOURCE_DATE}" +'#define U_BOOT_DATE "%b
%d %C%y"'; \
    LC_ALL=C $${date} -u -d "$${SOURCE_DATE}" +'#define U_BOOT_TIME "%T"'; \
    LC_ALL=C $${date} -u -d "$${SOURCE_DATE}" +'#define U_BOOT_TZ "%z"'; \
   else \
    return 42; \
   fi; \
  else \
   LC_ALL=C date +'#define U_BOOT_DATE "%b %d %C%y"'; \
   LC_ALL=C date +'#define U_BOOT_TIME "%T"'; \
   LC_ALL=C date +'#define U_BOOT_TZ "%z"'; \
  fi)
endef
--->8---


>>  CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
>>  		  -Wbitwise -Wno-return-void -D__CHECK_ENDIAN__ $(CF)
>> @@ -1281,9 +1285,9 @@ endef
>>  define filechk_timestamp.h
>>  	(if test -n "$${SOURCE_DATE_EPOCH}"; then \
>>  		SOURCE_DATE="@$${SOURCE_DATE_EPOCH}"; \
>> -		LC_ALL=C date -u -d "$${SOURCE_DATE}" +'#define U_BOOT_DATE "%b %d %C%y"'; \
>> -		LC_ALL=C date -u -d "$${SOURCE_DATE}" +'#define U_BOOT_TIME "%T"'; \
>> -		LC_ALL=C date -u -d "$${SOURCE_DATE}" +'#define U_BOOT_TZ "%z"'; \
>> +		LC_ALL=C $(DATE) -u -d "$${SOURCE_DATE}" +'#define U_BOOT_DATE "%b %d %C%y"'; \
>> +		LC_ALL=C $(DATE) -u -d "$${SOURCE_DATE}" +'#define U_BOOT_TIME "%T"'; \
>> +		LC_ALL=C $(DATE) -u -d "$${SOURCE_DATE}" +'#define U_BOOT_TZ "%z"'; \
>>  	else \
>>  		LC_ALL=C date +'#define U_BOOT_DATE "%b %d %C%y"'; \
>>  		LC_ALL=C date +'#define U_BOOT_TIME "%T"'; \
>> @@ -1295,6 +1299,11 @@ $(version_h): include/config/uboot.release FORCE
>>  	$(call filechk,version.h)
>>  
>>  $(timestamp_h): $(srctree)/Makefile FORCE
>> +ifneq ($(strip $(SOURCE_DATE_EPOCH)),)
>> +ifeq ($(strip $(DATE)),)
>> +	$(error "Your gdate/date.gnu/date does not support the '-u' and '-d' switches like GNU date does!")
>> +endif
>> +endif
>>  	$(call filechk,timestamp.h)
>>  
>>  # ---------------------------------------------------------------------------
>