Merge the bulk of Perl_magic_clearsig() into Perl_magic_setsig().

The comment at the top of Perl_magic_clearsig() said:
    XXX Some of this code was copied from Perl_magic_setsig. A little
    refactoring might be in order.
and it was not wrong.

Perl_magic_clearsig() is almost equivalent to Perl_magic_setsig() with the new
signal handler as "DEFAULT". Externally, the sv parameter to Perl_magic_setsig()
was Not NULL, so use a NULL sv to signal that the code is being called as
Perl_magic_clearsig(), for the places where the behaviour of the two diverges.

1 files changed, 29 insertions, 73 deletions

diff --git a/mg.c b/mg.c
index 025061fed0..55d46d2717 100644
--- a/mg.c
+++ b/mg.c
@@ -1265,70 +1265,10 @@ Perl_magic_getsig(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_clearsig(pTHX_ SV *sv, MAGIC *mg)
 {
-    /* XXX Some of this code was copied from Perl_magic_setsig. A little
-     * refactoring might be in order.
-     */
-    dVAR;
-    register const char * const s = MgPV_nolen_const(mg);
     PERL_ARGS_ASSERT_MAGIC_CLEARSIG;
     PERL_UNUSED_ARG(sv);
-    if (*s == '_') {
-	SV** svp = NULL;
-	if (strEQ(s,"__DIE__"))
-	    svp = &PL_diehook;
-	else if (strEQ(s,"__WARN__") && PL_warnhook != PERL_WARNHOOK_FATAL)
-	    svp = &PL_warnhook;
-	if (svp && *svp) {
-	    SV *const to_dec = *svp;
-	    *svp = NULL;
-	    SvREFCNT_dec(to_dec);
-	}
-    }
-    else {
-	/* Are we clearing a signal entry? */
-	const I32 i = whichsig(s);
-	if (i > 0) {
-#ifdef HAS_SIGPROCMASK
-	    sigset_t set, save;
-	    SV* save_sv;
-	    /* Avoid having the signal arrive at a bad time, if possible. */
-	    sigemptyset(&set);
-	    sigaddset(&set,i);
-	    sigprocmask(SIG_BLOCK, &set, &save);
-	    ENTER;
-	    save_sv = newSVpvn((char *)(&save), sizeof(sigset_t));
-	    SAVEFREESV(save_sv);
-	    SAVEDESTRUCTOR_X(restore_sigmask, save_sv);
-#endif
-	    PERL_ASYNC_CHECK();
-#if defined(FAKE_PERSISTENT_SIGNAL_HANDLERS) || defined(FAKE_DEFAULT_SIGNAL_HANDLERS)
-	    if (!PL_sig_handlers_initted) Perl_csighandler_init();
-#endif
-#ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
-	    PL_sig_defaulting[i] = 1;
-	    (void)rsignal(i, PL_csighandlerp);
-#else
-	    (void)rsignal(i, (Sighandler_t) SIG_DFL);
-#endif
-    	    if(PL_psig_name[i]) {
-    		SvREFCNT_dec(PL_psig_name[i]);
-    		PL_psig_name[i]=0;
-    	    }
-    	    if(PL_psig_ptr[i]) {
-		SV * const to_dec=PL_psig_ptr[i];
-    		PL_psig_ptr[i]=0;
-#ifdef HAS_SIGPROCMASK
-		LEAVE;
-#endif
-    		SvREFCNT_dec(to_dec);
-    	    }
-#ifdef HAS_SIGPROCMASK
-	    else
-		LEAVE;
-#endif
-	}
-    }
 
+    magic_setsig(NULL, mg);
     return sv_unmagic(sv, mg->mg_type);
 }
 
@@ -1431,6 +1371,7 @@ Perl_despatch_signals(pTHX)
     }
 }
 
+/* sv of NULL signifies that we're acting as magic_clearsig.  */
 int
 Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 {
@@ -1454,12 +1395,18 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
     if (*s == '_') {
 	if (strEQ(s,"__DIE__"))
 	    svp = &PL_diehook;
-	else if (strEQ(s,"__WARN__"))
+	else if (strEQ(s,"__WARN__")
+		 && (sv ? 1 : PL_warnhook != PERL_WARNHOOK_FATAL)) {
+	    /* Merge the existing behaviours, which are as follows:
+	       magic_setsig, we always set svp to &PL_warnhook
+	       (hence we always change the warnings handler)
+	       For magic_clearsig, we don't change the warnings handler if it's
+	       set to the &PL_warnhook.  */
 	    svp = &PL_warnhook;
-	else
+	} else if (sv)
 	    Perl_croak(aTHX_ "No such hook: %s", s);
 	i = 0;
-	if (*svp) {
+	if (svp && *svp) {
 	    if (*svp != PERL_WARNHOOK_FATAL)
 		to_dec = *svp;
 	    *svp = NULL;
@@ -1468,7 +1415,7 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
     else {
 	i = whichsig(s);	/* ...no, a brick */
 	if (i <= 0) {
-	    if (ckWARN(WARN_SIGNAL))
+	    if (sv && ckWARN(WARN_SIGNAL))
 		Perl_warner(aTHX_ packWARN(WARN_SIGNAL), "No such signal: SIG%s", s);
 	    return 0;
 	}
@@ -1494,12 +1441,17 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 #endif
 	SvREFCNT_dec(PL_psig_name[i]);
 	to_dec = PL_psig_ptr[i];
-	PL_psig_ptr[i] = SvREFCNT_inc_simple_NN(sv);
-	SvTEMP_off(sv); /* Make sure it doesn't go away on us */
-	PL_psig_name[i] = newSVpvn(s, len);
-	SvREADONLY_on(PL_psig_name[i]);
+	if (sv) {
+	    PL_psig_ptr[i] = SvREFCNT_inc_simple_NN(sv);
+	    SvTEMP_off(sv); /* Make sure it doesn't go away on us */
+	    PL_psig_name[i] = newSVpvn(s, len);
+	    SvREADONLY_on(PL_psig_name[i]);
+	} else {
+	    PL_psig_name[i] = NULL;
+	    PL_psig_ptr[i] = NULL;
+	}
     }
-    if (isGV_with_GP(sv) || SvROK(sv)) {
+    if (sv && (isGV_with_GP(sv) || SvROK(sv))) {
 	if (i) {
 	    (void)rsignal(i, PL_csighandlerp);
 #ifdef HAS_SIGPROCMASK
@@ -1512,8 +1464,12 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 	    SvREFCNT_dec(to_dec);
 	return 0;
     }
-    s = SvOK(sv) ? SvPV_force(sv,len) : "DEFAULT";
-    if (strEQ(s,"IGNORE")) {
+    if (sv && SvOK(sv)) {
+	s = SvPV_force(sv, len);
+    } else {
+	sv = NULL;
+    }
+    if (sv && strEQ(s,"IGNORE")) {
 	if (i) {
 #ifdef FAKE_PERSISTENT_SIGNAL_HANDLERS
 	    PL_sig_ignoring[i] = 1;
@@ -1523,7 +1479,7 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 #endif
 	}
     }
-    else if (strEQ(s,"DEFAULT") || !*s) {
+    else if (!sv || strEQ(s,"DEFAULT") || !len) {
 	if (i) {
 #ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
 	    PL_sig_defaulting[i] = 1;