From: Nicholas Clark <nick@ccl4.org>
Date: Sun, 16 Apr 2006 15:04:36 +0000 (+0000)
Subject: A scalar reference returned from a coderef in @INC is treated as the
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=34113e50dc4bebd1212d8cbfbf09a86a40b7a699;p=p5sagit%2Fp5-mst-13.2.git

A scalar reference returned from a coderef in @INC is treated as the
initial "content" of the file. When it is exhausted input is taken
from a real file handle, or a generator sub, if either exists.

p4raw-id: //depot/perl@27849
---

diff --git a/pp_ctl.c b/pp_ctl.c
index 43db9de..d783e1f 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -3067,6 +3067,7 @@ PP(pp_require)
     const I32 gimme = GIMME_V;
     int filter_has_file = 0;
     PerlIO *tryrsfp = NULL;
+    SV *filter_cache = NULL;
     SV *filter_state = NULL;
     SV *filter_sub = NULL;
     SV *hook_sv = NULL;
@@ -3174,6 +3175,16 @@ PP(pp_require)
 			SP -= count - 1;
 			arg = SP[i++];
 
+			if (SvROK(arg) && (SvTYPE(SvRV(arg)) <= SVt_PVLV)
+			    && !isGV_with_GP(SvRV(arg))) {
+			    filter_cache = SvRV(arg);
+			    SvREFCNT_inc_void_NN(filter_cache);
+
+			    if (i < count) {
+				arg = SP[i++];
+			    }
+			}
+
 			if (SvROK(arg) && SvTYPE(SvRV(arg)) == SVt_PVGV) {
 			    arg = SvRV(arg);
 			}
@@ -3205,11 +3216,11 @@ PP(pp_require)
 				filter_state = SP[i];
 				SvREFCNT_inc_simple_void(filter_state);
 			    }
+			}
 
-			    if (!tryrsfp) {
-				tryrsfp = PerlIO_open(BIT_BUCKET,
-						      PERL_SCRIPT_MODE);
-			    }
+			if (!tryrsfp && (filter_cache || filter_sub)) {
+			    tryrsfp = PerlIO_open(BIT_BUCKET,
+						  PERL_SCRIPT_MODE);
 			}
 			SP--;
 		    }
@@ -3224,6 +3235,10 @@ PP(pp_require)
 		    }
 
 		    filter_has_file = 0;
+		    if (filter_cache) {
+			SvREFCNT_dec(filter_cache);
+			filter_cache = NULL;
+		    }
 		    if (filter_state) {
 			SvREFCNT_dec(filter_state);
 			filter_state = NULL;
@@ -3361,11 +3376,12 @@ PP(pp_require)
     SAVESPTR(PL_compiling.cop_io);
     PL_compiling.cop_io = NULL;
 
-    if (filter_sub) {
+    if (filter_sub || filter_cache) {
 	SV * const datasv = filter_add(S_run_user_filter, NULL);
 	IoLINES(datasv) = filter_has_file;
 	IoTOP_GV(datasv) = (GV *)filter_state;
 	IoBOTTOM_GV(datasv) = (GV *)filter_sub;
+	IoFMT_GV(datasv) = (GV *)filter_cache;
     }
 
     /* switch to eval mode */
@@ -4519,15 +4535,11 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
     SV * const filter_state = (SV *)IoTOP_GV(datasv);
     SV * const filter_sub = (SV *)IoBOTTOM_GV(datasv);
     int status = 0;
-    /* Filter API says that the filter appends to the contents of the buffer.
-       Usually the buffer is "", so the details don't matter. But if it's not,
-       then clearly what it contains is already filtered by this filter, so we
-       don't want to pass it in a second time.
-       I'm going to use a mortal in case the upstream filter croaks.  */
     SV *upstream;
     STRLEN got_len;
     const char *got_p;
     const char *prune_from = NULL;
+    bool read_from_cache = FALSE;
 
     /* I was having segfault trouble under Linux 2.2.5 after a
        parse error occured.  (Had to hack around it with a test
@@ -4567,9 +4579,15 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 		maxlen -= cache_len;
 	    }
 	    SvOK_off(cache);
+	    read_from_cache = TRUE;
 	}
     }
 
+    /* Filter API says that the filter appends to the contents of the buffer.
+       Usually the buffer is "", so the details don't matter. But if it's not,
+       then clearly what it contains is already filtered by this filter, so we
+       don't want to pass it in a second time.
+       I'm going to use a mortal in case the upstream filter croaks.  */
     upstream = ((SvOK(buf_sv) && sv_len(buf_sv)) || SvGMAGICAL(buf_sv))
 	? sv_newmortal() : buf_sv;
     SvUPGRADE(upstream, SVt_PV);
@@ -4578,8 +4596,7 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 	status = FILTER_READ(idx+1, upstream, 0);
     }
 
-    assert(filter_sub);
-    if (status >= 0) {
+    if (filter_sub && status >= 0) {
 	dSP;
 	int count;
 
@@ -4650,7 +4667,11 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 	    status = 1;
     }
 
-    if (upstream != buf_sv) {
+    /* If they are at EOF but buf_sv has something in it, then they may never
+       have touched the SV upstream, so it may be undefined.  If we naively
+       concatenate it then we get a warning about use of uninitialised value.
+    */
+    if (upstream != buf_sv && (SvOK(upstream) || SvGMAGICAL(upstream))) {
 	sv_catsv(buf_sv, upstream);
     }
 
@@ -4667,6 +4688,12 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 	}
 	filter_del(S_run_user_filter);
     }
+    if (status == 0 && read_from_cache) {
+	/* If we read some data from the cache (and by getting here it implies
+	   that we emptied the cache) then we aren't yet at EOF, and mustn't
+	   report that to our caller.  */
+	return 1;
+    }
     return status;
 }
 
diff --git a/t/op/incfilter.t b/t/op/incfilter.t
index 97ce37a..0a5381e 100644
--- a/t/op/incfilter.t
+++ b/t/op/incfilter.t
@@ -14,7 +14,7 @@ BEGIN {
 use strict;
 use Filter::Util::Call;
 
-plan(tests => 128);
+plan(tests => 141);
 
 unshift @INC, sub {
     no warnings 'uninitialized';
@@ -44,14 +44,17 @@ do \&generator or die;
 # Check that the array dereferencing works ready for the more complex tests:
 do [\&generator] or die;
 
-do [sub {
-	my $param = $_[1];
-	is (ref $param, 'ARRAY', "Got our parameter");
-	$_ = shift @$param;
-	return defined $_ ? 1 : 0;
-    }, ["pass('Can return generators which take state');\n",
-	"pass('And return multiple lines');\n",
-	]] or die;
+sub generator_with_state {
+    my $param = $_[1];
+    is (ref $param, 'ARRAY', "Got our parameter");
+    $_ = shift @$param;
+    return defined $_ ? 1 : 0;
+}
+
+do [\&generator_with_state,
+    ["pass('Can return generators which take state');\n",
+     "pass('And return multiple lines');\n",
+    ]] or die;
    
 
 open $fh, "<", \'fail("File handles and filters work from \@INC");';
@@ -173,3 +176,27 @@ pass("You should see this line thrice");
 EOC
 
 do [$fh, sub {$_ .= $_ . $_; return;}] or die;
+
+do \"pass\n(\n'Scalar references are treated as initial file contents'\n)\n"
+or die;
+
+open $fh, "<", \"ss('The file is concatentated');";
+
+do [\'pa', $fh] or die;
+
+open $fh, "<", \"ff('Gur svygre vf bayl eha ba gur svyr');";
+
+do [\'pa', $fh, sub {tr/A-Za-z/N-ZA-Mn-za-m/; return;}] or die;
+
+open $fh, "<", \"SS('State also works');";
+
+do [\'pa', $fh, sub {s/($_[1])/lc $1/ge; return;}, "S"] or die;
+
+@lines = ('ss', '(', "'you can use a generator'", ')');
+
+do [\'pa', \&generator] or die;
+
+do [\'pa', \&generator_with_state,
+    ["ss('And generators which take state');\n",
+     "pass('And return multiple lines');\n",
+    ]] or die;