Re: [PATCH v6 1/3] Makefile: generate Perl header from template file

[Eric Sunshine]

On Sun, Mar 18, 2018 at 10:50 PM, Dan Jacques  wrote:
> Currently, the generated Perl script headers are emitted by commands in
> the Makefile. This mechanism restricts options to introduce alternative
> header content, needed by Perl runtime prefix support, and obscures the
> origin of the Perl script header.
>
> Change the Makefile to generate a header by processing a template file and
> move the header content into the "perl/" subdirectory. The processed
> generated will now be stored in the "GIT-PERL-HEADER" file. This allows

"processed generated"?

> the content of the Perl header to be controlled by changing the path of
> the template in the Makefile.
>
> Signed-off-by: Dan Jacques 

[PATCH v6 1/3] Makefile: generate Perl header from template file

[Dan Jacques]

Currently, the generated Perl script headers are emitted by commands in
the Makefile. This mechanism restricts options to introduce alternative
header content, needed by Perl runtime prefix support, and obscures the
origin of the Perl script header.

Change the Makefile to generate a header by processing a template file and
move the header content into the "perl/" subdirectory. The processed
generated will now be stored in the "GIT-PERL-HEADER" file. This allows
the content of the Perl header to be controlled by changing the path of
the template in the Makefile.

Signed-off-by: Dan Jacques 
Thanks-to: Ævar Arnfjörð Bjarmason 
Thanks-to: Johannes Schindelin 
---
 .gitignore |  1 +
 Makefile   | 27 +++---
 perl/header_templates/fixed_prefix.template.pl |  1 +
 3 files changed, 18 insertions(+), 11 deletions(-)
 create mode 100644 perl/header_templates/fixed_prefix.template.pl

diff --git a/.gitignore b/.gitignore
index 833ef3b0b..89bd7bd8a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 /GIT-LDFLAGS
 /GIT-PREFIX
 /GIT-PERL-DEFINES
+/GIT-PERL-HEADER
 /GIT-PYTHON-VARS
 /GIT-SCRIPT-DEFINES
 /GIT-USER-AGENT
diff --git a/Makefile b/Makefile
index a1d8775ad..e479822ce 100644
--- a/Makefile
+++ b/Makefile
@@ -1975,20 +1975,15 @@ git.res: git.rc GIT-VERSION-FILE
 $(SCRIPT_PERL_GEN): GIT-BUILD-OPTIONS
 
 ifndef NO_PERL
-$(SCRIPT_PERL_GEN):
-
+PERL_HEADER_TEMPLATE = perl/header_templates/fixed_prefix.template.pl
 PERL_DEFINES = $(PERL_PATH_SQ):$(PERLLIB_EXTRA_SQ):$(perllibdir_SQ)
-$(SCRIPT_PERL_GEN): % : %.perl GIT-PERL-DEFINES GIT-VERSION-FILE
+
+$(SCRIPT_PERL_GEN): % : %.perl GIT-PERL-DEFINES GIT-PERL-HEADER 
GIT-VERSION-FILE
$(QUIET_GEN)$(RM) $@ $@+ && \
-   INSTLIBDIR='$(perllibdir_SQ)' && \
-   INSTLIBDIR_EXTRA='$(PERLLIB_EXTRA_SQ)' && \
-   INSTLIBDIR="$$INSTLIBDIR$${INSTLIBDIR_EXTRA:+:$$INSTLIBDIR_EXTRA}" && \
sed -e '1{' \
-e 's|#!.*perl|#!$(PERL_PATH_SQ)|' \
-   -e 'h' \
-   -e 's=.*=use lib (split(/$(pathsep)/, $$ENV{GITPERLLIB} || 
"'"$$INSTLIBDIR"'"));=' \
-   -e 'H' \
-   -e 'x' \
+   -e 'rGIT-PERL-HEADER' \
+   -e 'G' \
-e '}' \
-e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
$< >$@+ && \
@@ -2002,6 +1997,16 @@ GIT-PERL-DEFINES: FORCE
echo "$$FLAGS" >$@; \
fi
 
+GIT-PERL-HEADER: $(PERL_HEADER_TEMPLATE) GIT-PERL-DEFINES Makefile
+   $(QUIET_GEN)$(RM) $@ && \
+   INSTLIBDIR='$(perllibdir_SQ)' && \
+   INSTLIBDIR_EXTRA='$(PERLLIB_EXTRA_SQ)' && \
+   INSTLIBDIR="$$INSTLIBDIR$${INSTLIBDIR_EXTRA:+:$$INSTLIBDIR_EXTRA}" && \
+   sed -e 's=@@PATHSEP@@=$(pathsep)=g' \
+   -e 's=@@INSTLIBDIR@@='$$INSTLIBDIR'=g' \
+   -e 's=@@PERLLIBDIR@@='$(perllibdir_SQ)'=g' \
+   $< >$@+ && \
+   mv $@+ $@
 
 .PHONY: gitweb
 gitweb:
@@ -2770,7 +2775,7 @@ ifndef NO_TCLTK
 endif
$(RM) GIT-VERSION-FILE GIT-CFLAGS GIT-LDFLAGS GIT-BUILD-OPTIONS
$(RM) GIT-USER-AGENT GIT-PREFIX
-   $(RM) GIT-SCRIPT-DEFINES GIT-PERL-DEFINES GIT-PYTHON-VARS
+   $(RM) GIT-SCRIPT-DEFINES GIT-PERL-DEFINES GIT-PERL-HEADER 
GIT-PYTHON-VARS
 
 .PHONY: all install profile-clean clean strip
 .PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell
diff --git a/perl/header_templates/fixed_prefix.template.pl 
b/perl/header_templates/fixed_prefix.template.pl
new file mode 100644
index 0..857b4391a
--- /dev/null
+++ b/perl/header_templates/fixed_prefix.template.pl
@@ -0,0 +1 @@
+use lib (split(/@@PATHSEP@@/, $ENV{GITPERLLIB} || '@@INSTLIBDIR@@'));
-- 
2.15.0.chromium12