Introduce macros to simplify @INC setting

Distro trends to customize @INC, and to maintain
patches to change the order of @INC or add custom entries.

The goal of this patch is to abstract calls to 'S_incpush_use_sep'
and simplify reordering @INC.

This commit makes the code from perl.c more comfortable to read
by introducing several 'INCPUSH_*' macros for every
'S_incpush_use_sep' call so we can easily reorder them.

3 files changed, 205 insertions, 124 deletions

diff --git a/MANIFEST b/MANIFEST
index 4c837b6a01..add651c87f 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -4951,6 +4951,7 @@ parser.h			parser object header
 patchlevel.h			The current patch level of perl
 perl.c				main()
 perl.h				Global declarations
+perl_inc_macro.h		macro used to set \@INC using S_incpush_use_sep
 perl_langinfo.h			Perl's version of <langinfo.h>
 perlapi.c			Perl API functions
 perlapi.h			Perl API function declarations
diff --git a/perl.c b/perl.c
index 7c1994bbe3..25b4a26740 100644
--- a/perl.c
+++ b/perl.c
@@ -4581,134 +4581,24 @@ S_init_perllib(pTHX)
     /* miniperl gets just -I..., the split of $ENV{PERL5LIB}, and "." in @INC
        (and not the architecture specific directories from $ENV{PERL5LIB}) */
 
+#include "perl_inc_macro.h"
 /* Use the ~-expanded versions of APPLLIB (undocumented),
     SITEARCH, SITELIB, VENDORARCH, VENDORLIB, ARCHLIB and PRIVLIB
 */
-#ifdef APPLLIB_EXP
-    S_incpush_use_sep(aTHX_ STR_WITH_LEN(APPLLIB_EXP),
-		      INCPUSH_ADD_SUB_DIRS|INCPUSH_CAN_RELOCATE);
-#endif
-
-#ifdef SITEARCH_EXP
-    /* sitearch is always relative to sitelib on Windows for
-     * DLL-based path intuition to work correctly */
-#  if !defined(WIN32)
-	S_incpush_use_sep(aTHX_ STR_WITH_LEN(SITEARCH_EXP),
-			  INCPUSH_CAN_RELOCATE);
-#  endif
-#endif
-
-#ifdef SITELIB_EXP
-#  if defined(WIN32)
-    /* this picks up sitearch as well */
-	s = PerlEnv_sitelib_path(PERL_FS_VERSION, &len);
-	if (s)
-	    incpush_use_sep(s, len, INCPUSH_ADD_SUB_DIRS|INCPUSH_CAN_RELOCATE);
-#  else
-	S_incpush_use_sep(aTHX_ STR_WITH_LEN(SITELIB_EXP), INCPUSH_CAN_RELOCATE);
-#  endif
-#endif
-
-#ifdef PERL_VENDORARCH_EXP
-    /* vendorarch is always relative to vendorlib on Windows for
-     * DLL-based path intuition to work correctly */
-#  if !defined(WIN32)
-    S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_VENDORARCH_EXP),
-		      INCPUSH_CAN_RELOCATE);
-#  endif
-#endif
-
-#ifdef PERL_VENDORLIB_EXP
-#  if defined(WIN32)
-    /* this picks up vendorarch as well */
-	s = PerlEnv_vendorlib_path(PERL_FS_VERSION, &len);
-	if (s)
-	    incpush_use_sep(s, len, INCPUSH_ADD_SUB_DIRS|INCPUSH_CAN_RELOCATE);
-#  else
-	S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_VENDORLIB_EXP),
-			  INCPUSH_CAN_RELOCATE);
-#  endif
-#endif
+    INCPUSH_APPLLIB_EXP
+    INCPUSH_SITEARCH_EXP
+    INCPUSH_SITELIB_EXP
+    INCPUSH_PERL_VENDORARCH_EXP
+    INCPUSH_PERL_VENDORLIB_EXP
+    INCPUSH_ARCHLIB_EXP
+    INCPUSH_PRIVLIB_EXP
+    INCPUSH_PERL_OTHERLIBDIRS
+    INCPUSH_PERL5LIB
+    INCPUSH_APPLLIB_OLD_EXP
+    INCPUSH_SITELIB_STEM
+    INCPUSH_PERL_VENDORLIB_STEM
+    INCPUSH_PERL_OTHERLIBDIRS_ARCHONLY
 
-#ifdef ARCHLIB_EXP
-    S_incpush_use_sep(aTHX_ STR_WITH_LEN(ARCHLIB_EXP), INCPUSH_CAN_RELOCATE);
-#endif
-
-#ifndef PRIVLIB_EXP
-#  define PRIVLIB_EXP "/usr/local/lib/perl5:/usr/local/lib/perl"
-#endif
-
-#if defined(WIN32)
-    s = PerlEnv_lib_path(PERL_FS_VERSION, &len);
-    if (s)
-	incpush_use_sep(s, len, INCPUSH_ADD_SUB_DIRS|INCPUSH_CAN_RELOCATE);
-#elif defined(NETWARE)
-    S_incpush_use_sep(aTHX_ PRIVLIB_EXP, 0, INCPUSH_CAN_RELOCATE);
-#else
-    S_incpush_use_sep(aTHX_ STR_WITH_LEN(PRIVLIB_EXP), INCPUSH_CAN_RELOCATE);
-#endif
-
-#ifdef PERL_OTHERLIBDIRS
-    S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_OTHERLIBDIRS),
-		      INCPUSH_ADD_VERSIONED_SUB_DIRS|INCPUSH_NOT_BASEDIR
-		      |INCPUSH_CAN_RELOCATE);
-#endif
-
-    if (!TAINTING_get) {
-#ifndef VMS
-/*
- * It isn't possible to delete an environment variable with
- * PERL_USE_SAFE_PUTENV set unless unsetenv() is also available, so in that
- * case we treat PERL5LIB as undefined if it has a zero-length value.
- */
-#if defined(PERL_USE_SAFE_PUTENV) && ! defined(HAS_UNSETENV)
-	if (perl5lib && *perl5lib != '\0')
-#else
-	if (perl5lib)
-#endif
-	    incpush_use_sep(perl5lib, 0,
-			    INCPUSH_ADD_OLD_VERS|INCPUSH_NOT_BASEDIR);
-#else /* VMS */
-	/* Treat PERL5?LIB as a possible search list logical name -- the
-	 * "natural" VMS idiom for a Unix path string.  We allow each
-	 * element to be a set of |-separated directories for compatibility.
-	 */
-	char buf[256];
-	int idx = 0;
-	if (vmstrnenv("PERL5LIB",buf,0,NULL,0))
-	    do {
-		incpush_use_sep(buf, 0,
-				INCPUSH_ADD_OLD_VERS|INCPUSH_NOT_BASEDIR);
-	    } while (vmstrnenv("PERL5LIB",buf,++idx,NULL,0));
-#endif /* VMS */
-    }
-
-/* Use the ~-expanded versions of APPLLIB (undocumented),
-    SITELIB and VENDORLIB for older versions
-*/
-#ifdef APPLLIB_EXP
-    S_incpush_use_sep(aTHX_ STR_WITH_LEN(APPLLIB_EXP), INCPUSH_ADD_OLD_VERS
-		      |INCPUSH_NOT_BASEDIR|INCPUSH_CAN_RELOCATE);
-#endif
-
-#if defined(SITELIB_STEM) && defined(PERL_INC_VERSION_LIST)
-    /* Search for version-specific dirs below here */
-    S_incpush_use_sep(aTHX_ STR_WITH_LEN(SITELIB_STEM),
-		      INCPUSH_ADD_OLD_VERS|INCPUSH_CAN_RELOCATE);
-#endif
-
-
-#if defined(PERL_VENDORLIB_STEM) && defined(PERL_INC_VERSION_LIST)
-    /* Search for version-specific dirs below here */
-    S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_VENDORLIB_STEM),
-		      INCPUSH_ADD_OLD_VERS|INCPUSH_CAN_RELOCATE);
-#endif
-
-#ifdef PERL_OTHERLIBDIRS
-    S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_OTHERLIBDIRS),
-		      INCPUSH_ADD_OLD_VERS|INCPUSH_ADD_ARCHONLY_SUB_DIRS
-		      |INCPUSH_CAN_RELOCATE);
-#endif
 #endif /* !PERL_IS_MINIPERL */
 
     if (!TAINTING_get) {
diff --git a/perl_inc_macro.h b/perl_inc_macro.h
new file mode 100644
index 0000000000..892af1e2e3
--- /dev/null
+++ b/perl_inc_macro.h
@@ -0,0 +1,190 @@
+/* just define a list of macros to push elements in INC
+*  so we can easily use them and change order on demand
+*
+* list of available INCPUSH macros
+* - INCPUSH_APPLLIB_EXP
+* - INCPUSH_SITEARCH_EXP
+* - INCPUSH_SITELIB_EXP
+* - INCPUSH_PERL_VENDORARCH_EXP
+* - INCPUSH_PERL_VENDORLIB_EXP
+* - INCPUSH_ARCHLIB_EXP
+* - INCPUSH_PRIVLIB_EXP
+* - INCPUSH_PERL_OTHERLIBDIRS
+* - INCPUSH_PERL5LIB
+* - INCPUSH_APPLLIB_OLD_EXP
+* - INCPUSH_SITELIB_STEM
+* - INCPUSH_PERL_VENDORLIB_STEM
+* - INCPUSH_PERL_OTHERLIBDIRS_ARCHONLY
+*/
+
+#ifndef DEFINE_INC_MACROS
+
+/* protect against multiple inclusions */
+#define DEFINE_INC_MACROS 1
+
+#ifdef APPLLIB_EXP
+#	define INCPUSH_APPLLIB_EXP  S_incpush_use_sep(aTHX_ STR_WITH_LEN(APPLLIB_EXP), \
+		      INCPUSH_ADD_SUB_DIRS|INCPUSH_CAN_RELOCATE);
+#endif
+
+#ifdef SITEARCH_EXP
+    /* sitearch is always relative to sitelib on Windows for
+     * DLL-based path intuition to work correctly */
+#  if !defined(WIN32)
+#	define INCPUSH_SITEARCH_EXP S_incpush_use_sep(aTHX_ STR_WITH_LEN(SITEARCH_EXP), \
+			  INCPUSH_CAN_RELOCATE);
+#  endif
+#endif
+
+#ifdef SITELIB_EXP
+#  if defined(WIN32)
+    /* this picks up sitearch as well */
+#	  define INCPUSH_SITELIB_EXP s = PerlEnv_sitelib_path(PERL_FS_VERSION, &len); \
+		if (s) incpush_use_sep(s, len, INCPUSH_ADD_SUB_DIRS|INCPUSH_CAN_RELOCATE);
+#  else
+#	  define INCPUSH_SITELIB_EXP S_incpush_use_sep(aTHX_ STR_WITH_LEN(SITELIB_EXP), \
+		INCPUSH_CAN_RELOCATE);
+#  endif
+#endif
+
+#ifdef PERL_VENDORARCH_EXP
+    /* vendorarch is always relative to vendorlib on Windows for
+     * DLL-based path intuition to work correctly */
+#  if !defined(WIN32)
+#		define INCPUSH_PERL_VENDORARCH_EXP  S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_VENDORARCH_EXP), INCPUSH_CAN_RELOCATE);
+#  endif
+#endif
+
+#ifdef PERL_VENDORLIB_EXP
+#  if defined(WIN32)
+    /* this picks up vendorarch as well */
+#		define INCPUSH_PERL_VENDORLIB_EXP s = PerlEnv_vendorlib_path(PERL_FS_VERSION, &len); \
+			if (s) incpush_use_sep(s, len, INCPUSH_ADD_SUB_DIRS|INCPUSH_CAN_RELOCATE);
+#  else
+#		define INCPUSH_PERL_VENDORLIB_EXP S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_VENDORLIB_EXP), INCPUSH_CAN_RELOCATE);
+#  endif
+#endif
+
+#ifdef ARCHLIB_EXP
+#	define INCPUSH_ARCHLIB_EXP S_incpush_use_sep(aTHX_ STR_WITH_LEN(ARCHLIB_EXP), INCPUSH_CAN_RELOCATE);
+#endif
+
+/* used by INCPUSH_PRIVLIB_EXP */
+#ifndef PRIVLIB_EXP
+#  define PRIVLIB_EXP "/usr/local/lib/perl5:/usr/local/lib/perl"
+#endif
+
+#if defined(WIN32)
+#	define INCPUSH_PRIVLIB_EXP s = PerlEnv_lib_path(PERL_FS_VERSION, &len); \
+    if (s) incpush_use_sep(s, len, INCPUSH_ADD_SUB_DIRS|INCPUSH_CAN_RELOCATE);
+#elif defined(NETWARE)
+#	define INCPUSH_PRIVLIB_EXP S_incpush_use_sep(aTHX_ PRIVLIB_EXP, 0, INCPUSH_CAN_RELOCATE);
+#else
+#	define INCPUSH_PRIVLIB_EXP S_incpush_use_sep(aTHX_ STR_WITH_LEN(PRIVLIB_EXP), INCPUSH_CAN_RELOCATE);
+#endif
+
+#ifdef PERL_OTHERLIBDIRS
+#	define INCPUSH_PERL_OTHERLIBDIRS S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_OTHERLIBDIRS), \
+		      INCPUSH_ADD_VERSIONED_SUB_DIRS|INCPUSH_NOT_BASEDIR|INCPUSH_CAN_RELOCATE);
+#endif
+
+
+/* submacros for INCPUSH_PERL5LIB */
+
+#if defined(PERL_USE_SAFE_PUTENV) && ! defined(HAS_UNSETENV)
+# 	define _INCPUSH_PERL5LIB_IF	if (perl5lib && *perl5lib != '\0')
+#else
+# 	define _INCPUSH_PERL5LIB_IF	if (perl5lib)
+#endif
+
+#ifndef VMS
+/*
+ * It isn't possible to delete an environment variable with
+ * PERL_USE_SAFE_PUTENV set unless unsetenv() is also available, so in that
+ * case we treat PERL5LIB as undefined if it has a zero-length value.
+ */
+# define _INCPUSH_PERL5LIB_ADD _INCPUSH_PERL5LIB_IF incpush_use_sep(perl5lib, 0, INCPUSH_ADD_OLD_VERS|INCPUSH_NOT_BASEDIR);
+#else
+/* VMS */
+	/* Treat PERL5?LIB as a possible search list logical name -- the
+	 * "natural" VMS idiom for a Unix path string.  We allow each
+	 * element to be a set of |-separated directories for compatibility.
+	 */
+# define _INCPUSH_PERL5LIB_ADD char buf[256]; \
+	int idx = 0; \
+	if (vmstrnenv("PERL5LIB",buf,0,NULL,0)) \
+	    do { \
+		incpush_use_sep(buf, 0, \
+				INCPUSH_ADD_OLD_VERS|INCPUSH_NOT_BASEDIR); \
+	    } while (vmstrnenv("PERL5LIB",buf,++idx,NULL,0));
+#endif
+
+/* this macro is special and use submacros from above */
+#define INCPUSH_PERL5LIB if (!TAINTING_get) { _INCPUSH_PERL5LIB_ADD }
+
+/* Use the ~-expanded versions of APPLLIB (undocumented),
+    SITELIB and VENDORLIB for older versions
+*/
+#ifdef APPLLIB_EXP
+#	define INCPUSH_APPLLIB_OLD_EXP S_incpush_use_sep(aTHX_ STR_WITH_LEN(APPLLIB_EXP), \
+	    INCPUSH_ADD_OLD_VERS|INCPUSH_NOT_BASEDIR|INCPUSH_CAN_RELOCATE);
+#endif
+
+#if defined(SITELIB_STEM) && defined(PERL_INC_VERSION_LIST)
+    /* Search for version-specific dirs below here */
+#	define INCPUSH_SITELIB_STEM   S_incpush_use_sep(aTHX_ STR_WITH_LEN(SITELIB_STEM), \
+		      INCPUSH_ADD_OLD_VERS|INCPUSH_CAN_RELOCATE);
+#endif
+
+
+#if defined(PERL_VENDORLIB_STEM) && defined(PERL_INC_VERSION_LIST)
+    /* Search for version-specific dirs below here */
+#	define INCPUSH_PERL_VENDORLIB_STEM    S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_VENDORLIB_STEM), \
+		      INCPUSH_ADD_OLD_VERS|INCPUSH_CAN_RELOCATE);
+#endif
+
+#ifdef PERL_OTHERLIBDIRS
+#	define INCPUSH_PERL_OTHERLIBDIRS_ARCHONLY  S_incpush_use_sep(aTHX_ STR_WITH_LEN(PERL_OTHERLIBDIRS), \
+		      INCPUSH_ADD_OLD_VERS|INCPUSH_ADD_ARCHONLY_SUB_DIRS|INCPUSH_CAN_RELOCATE);
+#endif
+
+
+/* define all undefined macros... */
+#ifndef INCPUSH_APPLLIB_EXP
+#define INCPUSH_APPLLIB_EXP
+#endif
+#ifndef INCPUSH_SITEARCH_EXP
+#define INCPUSH_SITEARCH_EXP
+#endif
+#ifndef INCPUSH_SITELIB_EXP
+#define INCPUSH_SITELIB_EXP
+#endif
+#ifndef INCPUSH_PERL_VENDORARCH_EXP
+#define INCPUSH_PERL_VENDORARCH_EXP
+#endif
+#ifndef INCPUSH_PERL_VENDORLIB_EXP
+#define INCPUSH_PERL_VENDORLIB_EXP
+#endif
+#ifndef INCPUSH_PRIVLIB_EXP
+#define INCPUSH_PRIVLIB_EXP
+#endif
+#ifndef INCPUSH_PERL_OTHERLIBDIRS
+#define INCPUSH_PERL_OTHERLIBDIRS
+#endif
+#ifndef INCPUSH_PERL5LIB
+#define INCPUSH_PERL5LIB
+#endif
+#ifndef INCPUSH_APPLLIB_OLD_EXP
+#define INCPUSH_APPLLIB_OLD_EXP
+#endif
+#ifndef INCPUSH_SITELIB_STEM
+#define INCPUSH_SITELIB_STEM
+#endif
+#ifndef INCPUSH_PERL_VENDORLIB_STEM
+#define INCPUSH_PERL_VENDORLIB_STEM
+#endif
+#ifndef INCPUSH_PERL_OTHERLIBDIRS_ARCHONLY
+#define INCPUSH_PERL_OTHERLIBDIRS_ARCHONLY
+#endif
+
+#endif /* DEFINE_INC_MACROS */
\ No newline at end of file