From 85dca89a8f321bc581a3d365d95ab0c56368ed78 Mon Sep 17 00:00:00 2001
From: Nicholas Clark <nick@ccl4.org>
Date: Sat, 8 Aug 2009 15:01:48 +0100
Subject: [PATCH] Perl_newIO() can become a mathom by making newIO() a wrapper
 around newSV_type() and tweaking Perl_sv_upgrade().

---
 embed.fnc |  2 +-
 embed.h   |  2 --
 gv.c      | 21 ---------------------
 mathoms.c |  7 +++++++
 proto.h   |  4 ++--
 sv.c      | 16 +++++++++++++++-
 sv.h      |  3 +++
 7 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/embed.fnc b/embed.fnc
index 3ada68a..71bb983 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -682,7 +682,7 @@ Apa	|OP*	|newGVREF	|I32 type|NULLOK OP* o
 ApaR	|OP*	|newHVREF	|NN OP* o
 AmdbR	|HV*	|newHV
 ApaR	|HV*	|newHVhv	|NULLOK HV *hv
-Apa	|IO*	|newIO
+Apabm	|IO*	|newIO
 Apa	|OP*	|newLISTOP	|I32 type|I32 flags|NULLOK OP* first|NULLOK OP* last
 #ifdef USE_ITHREADS
 Apa	|OP*	|newPADOP	|I32 type|I32 flags|NN SV* sv
diff --git a/embed.h b/embed.h
index ae708d6..e1e6420 100644
--- a/embed.h
+++ b/embed.h
@@ -570,7 +570,6 @@
 #define newGVREF		Perl_newGVREF
 #define newHVREF		Perl_newHVREF
 #define newHVhv			Perl_newHVhv
-#define newIO			Perl_newIO
 #define newLISTOP		Perl_newLISTOP
 #ifdef USE_ITHREADS
 #define newPADOP		Perl_newPADOP
@@ -2907,7 +2906,6 @@
 #define newGVREF(a,b)		Perl_newGVREF(aTHX_ a,b)
 #define newHVREF(a)		Perl_newHVREF(aTHX_ a)
 #define newHVhv(a)		Perl_newHVhv(aTHX_ a)
-#define newIO()			Perl_newIO(aTHX)
 #define newLISTOP(a,b,c,d)	Perl_newLISTOP(aTHX_ a,b,c,d)
 #ifdef USE_ITHREADS
 #define newPADOP(a,b,c)		Perl_newPADOP(aTHX_ a,b,c)
diff --git a/gv.c b/gv.c
index d46b253..782bfe6 100644
--- a/gv.c
+++ b/gv.c
@@ -1485,27 +1485,6 @@ Perl_gv_efullname4(pTHX_ SV *sv, const GV *gv, const char *prefix, bool keepmain
     gv_fullname4(sv, egv ? egv : gv, prefix, keepmain);
 }
 
-IO *
-Perl_newIO(pTHX)
-{
-    dVAR;
-    GV *iogv;
-    IO * const io = MUTABLE_IO(newSV_type(SVt_PVIO));
-    /* This used to read SvREFCNT(io) = 1;
-       It's not clear why the reference count needed an explicit reset. NWC
-    */
-    assert (SvREFCNT(io) == 1);
-    SvOBJECT_on(io);
-    /* Clear the stashcache because a new IO could overrule a package name */
-    hv_clear(PL_stashcache);
-    iogv = gv_fetchpvs("FileHandle::", 0, SVt_PVHV);
-    /* unless exists($main::{FileHandle}) and defined(%main::FileHandle::) */
-    if (!(iogv && GvHV(iogv) && HvARRAY(GvHV(iogv))))
-      iogv = gv_fetchpvs("IO::Handle::", GV_ADD, SVt_PVHV);
-    SvSTASH_set(io, MUTABLE_HV(SvREFCNT_inc(GvHV(iogv))));
-    return io;
-}
-
 void
 Perl_gv_check(pTHX_ const HV *stash)
 {
diff --git a/mathoms.c b/mathoms.c
index 5ae5d2d..012ccc2 100644
--- a/mathoms.c
+++ b/mathoms.c
@@ -76,6 +76,7 @@ PERL_CALLCONV int Perl_printf_nocontext(const char *format, ...);
 PERL_CALLCONV int Perl_magic_setglob(pTHX_ SV* sv, MAGIC* mg);
 PERL_CALLCONV AV * Perl_newAV(pTHX);
 PERL_CALLCONV HV * Perl_newHV(pTHX);
+PERL_CALLCONV IO * Perl_newIO(pTHX);
 
 /* ref() is now a macro using Perl_doref;
  * this version provided for binary compatibility only.
@@ -1499,6 +1500,12 @@ Perl_gv_HVadd(pTHX_ register GV *gv)
     return gv_HVadd(gv);
 }
 
+IO *
+Perl_newIO(pTHX)
+{
+    return MUTABLE_IO(newSV_type(SVt_PVIO));
+}
+
 #endif /* NO_MATHOMS */
 
 /*
diff --git a/proto.h b/proto.h
index aee22c0..90ffd21 100644
--- a/proto.h
+++ b/proto.h
@@ -2123,9 +2123,9 @@ PERL_CALLCONV HV*	Perl_newHVhv(pTHX_ HV *hv)
 			__attribute__malloc__
 			__attribute__warn_unused_result__;
 
-PERL_CALLCONV IO*	Perl_newIO(pTHX)
+/* PERL_CALLCONV IO*	Perl_newIO(pTHX)
 			__attribute__malloc__
-			__attribute__warn_unused_result__;
+			__attribute__warn_unused_result__; */
 
 PERL_CALLCONV OP*	Perl_newLISTOP(pTHX_ I32 type, I32 flags, OP* first, OP* last)
 			__attribute__malloc__
diff --git a/sv.c b/sv.c
index a5a3554..b8daf81 100644
--- a/sv.c
+++ b/sv.c
@@ -1430,8 +1430,22 @@ Perl_sv_upgrade(pTHX_ register SV *const sv, svtype new_type)
 	    SvNV_set(sv, 0);
 #endif
 
-	if (new_type == SVt_PVIO)
+	if (new_type == SVt_PVIO) {
+	    IO * const io = MUTABLE_IO(sv);
+	    GV *iogv = gv_fetchpvs("FileHandle::", 0, SVt_PVHV);
+
+	    SvOBJECT_on(io);
+	    /* Clear the stashcache because a new IO could overrule a package
+	       name */
+	    hv_clear(PL_stashcache);
+
+	    /* unless exists($main::{FileHandle}) and
+	       defined(%main::FileHandle::) */
+	    if (!(iogv && GvHV(iogv) && HvARRAY(GvHV(iogv))))
+		iogv = gv_fetchpvs("IO::Handle::", GV_ADD, SVt_PVHV);
+	    SvSTASH_set(io, MUTABLE_HV(SvREFCNT_inc(GvHV(iogv))));
 	    IoPAGE_LEN(sv) = 60;
+	}
 	if (old_type < SVt_PV) {
 	    /* referant will be NULL unless the old type was SVt_IV emulating
 	       SVt_RV */
diff --git a/sv.h b/sv.h
index 0d275d2..90771a4 100644
--- a/sv.h
+++ b/sv.h
@@ -2016,6 +2016,9 @@ Evaluates I<sv> more than once. Sets I<len> to 0 if C<SvOOK(sv)> is false.
 	}								\
     } STMT_END
 #endif
+
+#define newIO()	MUTABLE_IO(newSV_type(SVt_PVIO))
+
 /*
  * Local variables:
  * c-indentation-style: bsd
-- 
2.7.4