From: Vincent Pit <vince@profvince.com>
Date: Sat, 7 Feb 2009 12:10:52 +0000 (+0100)
Subject: Set $_[2] to the default length for len magic on scalars
X-Git-Tag: v0.29~3
X-Git-Url: http://git.vpit.fr/?p=perl%2Fmodules%2FVariable-Magic.git;a=commitdiff_plain;h=9cad66dcbed4359e8d70b1bc1a26000b475a400c

Set $_[2] to the default length for len magic on scalars
---

diff --git a/Magic.xs b/Magic.xs
index 5b4576a..6585817 100644
--- a/Magic.xs
+++ b/Magic.xs
@@ -546,13 +546,11 @@ STATIC int vmg_svt_set(pTHX_ SV *sv, MAGIC *mg) {
 
 STATIC U32 vmg_svt_len(pTHX_ SV *sv, MAGIC *mg) {
  SV *svr;
- I32 len, has_array;
- U32 ret;
+ U32 len, ret;
+ svtype t = SvTYPE(sv);
 
  dSP;
 
- has_array = SvTYPE(sv) == SVt_PVAV;
-
  ENTER;
  SAVETMPS;
 
@@ -560,9 +558,17 @@ STATIC U32 vmg_svt_len(pTHX_ SV *sv, MAGIC *mg) {
  EXTEND(SP, 3);
  PUSHs(sv_2mortal(newRV_inc(sv)));
  PUSHs(mg->mg_obj ? mg->mg_obj : &PL_sv_undef);
- if (has_array) {
+ if (t < SVt_PVAV) {
+  STRLEN l;
+  U8 *s = (U8 *) SvPV_const(sv, l);
+  if (DO_UTF8(sv))
+   len = utf8_length(s, s + l);
+  else
+   len = l;
+  mPUSHu(len);
+ } else if (t == SVt_PVAV) {
   len = av_len((AV *) sv) + 1;
-  mPUSHi(len);
+  mPUSHu(len);
  } else {
   len = 0;
   PUSHs(&PL_sv_undef);
@@ -579,7 +585,7 @@ STATIC U32 vmg_svt_len(pTHX_ SV *sv, MAGIC *mg) {
  FREETMPS;
  LEAVE;
 
- return has_array ? ret - 1 : ret;
+ return t == SVt_PVAV ? ret - 1 : ret;
 }
 
 STATIC int vmg_svt_clear(pTHX_ SV *sv, MAGIC *mg) {
diff --git a/lib/Variable/Magic.pm b/lib/Variable/Magic.pm
index aa7ee22..2700f71 100644
--- a/lib/Variable/Magic.pm
+++ b/lib/Variable/Magic.pm
@@ -329,8 +329,8 @@ Other arguments are specific to the magic hooked :
 
 C<len>
 
-When the variable is an array, C<$_[2]> contains the normal length.
-The callback is also expected to return the new scalar or array length.
+When the variable is an array or a scalar, C<$_[2]> contains the non-magical length.
+The callback can return the new scalar or array length to use, or C<undef> to default to the normal length.
 
 =item *
 
diff --git a/t/22-len.t b/t/22-len.t
index 5d3ae92..3b8039e 100644
--- a/t/22-len.t
+++ b/t/22-len.t
@@ -3,14 +3,15 @@
 use strict;
 use warnings;
 
-use Test::More tests => 13;
+use Test::More tests => 33;
 
 use Variable::Magic qw/wizard cast VMG_COMPAT_SCALAR_LENGTH_NOLEN/;
 
 my $c = 0;
 
 my $n = 1 + int rand 1000;
-my $wiz = wizard len => sub { ++$c; return $n };
+my $d;
+my $wiz = wizard len => sub { $d = $_[2]; ++$c; return $n };
 is $c, 0, 'len: wizard() doesn\'t trigger magic';
 
 my @a = qw/a b c/;
@@ -20,46 +21,106 @@ cast @a, $wiz;
 is $c, 0, 'len: cast on array doesn\'t trigger magic';
 
 $c = 0;
+$d = undef;
 my $b = scalar @a;
 is $c, 1,  'len: get array length triggers magic correctly';
+is $d, 3,  'len: get array length have correct default length';
 is $b, $n, 'len: get array length correctly';
 
 $c = 0;
+$d = undef;
 $b = $#a;
 is $c, 1,      'len: get last array index triggers magic correctly';
+is $d, 3,      'len: get last array index have correct default length';
 is $b, $n - 1, 'len: get last array index correctly';
 
 $n = 0;
 
 $c = 0;
+$d = undef;
 $b = scalar @a;
 is $c, 1, 'len: get array length 0 triggers magic correctly';
+is $d, 3, 'len: get array length 0 have correct default length';
 is $b, 0, 'len: get array length 0 correctly';
 
+$n = undef;
+@a = ();
+cast @a, $wiz;
+
+$c = 0;
+$d = undef;
+$b = scalar @a;
+is $c, 1, 'len: get empty array length triggers magic correctly';
+is $d, 0, 'len: get empty array length have correct default length';
+is $b, 0, 'len: get empty array length correctly';
+
+$c = 0;
+$d = undef;
+$b = $#a;
+is $c, 1,  'len: get last empty array index triggers magic correctly';
+is $d, 0,  'len: get last empty array index have correct default length';
+is $b, -1, 'len: get last empty array index correctly';
+
 SKIP: {
- skip 'length() no longer calls mg_len magic' => 5 if VMG_COMPAT_SCALAR_LENGTH_NOLEN;
+ skip 'length() no longer calls mg_len magic' => 16 if VMG_COMPAT_SCALAR_LENGTH_NOLEN;
 
  $c = 0;
  $n = 1 + int rand 1000;
  # length magic on scalars needs also get magic to be triggered.
  $wiz = wizard get => sub { return 'anything' },
-               len => sub { ++$c; return $n };
+               len => sub { $d = $_[2]; ++$c; return $n };
 
- my $x = int rand 1000;
+ my $x = 6789;
 
  $c = 0;
  cast $x, $wiz;
  is $c, 0, 'len: cast on scalar doesn\'t trigger magic';
 
  $c = 0;
+ $d = undef;
  $b = length $x;
  is $c, 1,  'len: get scalar length triggers magic correctly';
+ is $d, 4,  'len: get scalar length have correct default length';
  is $b, $n, 'len: get scalar length correctly';
 
  $n = 0;
 
  $c = 0;
+ $d = undef;
  $b = length $x;
  is $c, 1,  'len: get scalar length 0 triggers magic correctly';
+ is $d, 4,  'len: get scalar length 0 have correct default length';
  is $b, $n, 'len: get scalar length 0 correctly';
+
+ $n = undef;
+ $x = '';
+ cast $x, $wiz;
+
+ $c = 0;
+ $d = undef;
+ $b = length $x;
+ is $c, 1, 'len: get empty scalar length triggers magic correctly';
+ is $d, 0, 'len: get empty scalar length have correct default length';
+ is $b, 0, 'len: get empty scalar length correctly';
+
+ $x = "\x{20AB}ongs";
+ cast $x, $wiz;
+
+ {
+  use bytes;
+
+  $c = 0;
+  $d = undef;
+  $b = length $x;
+  is $c, 1,  'len: get utf8 scalar length in bytes triggers magic correctly';
+  is $d, 7,  'len: get utf8 scalar length in bytes have correct default length';
+  is $b, $d, 'len: get utf8 scalar length in bytes correctly';
+ }
+
+ $c = 0;
+ $d = undef;
+ $b = length $x;
+ is $c, 1,  'len: get utf8 scalar length triggers magic correctly';
+ is $d, 5,  'len: get utf8 scalar length have correct default length';
+ is $b, $d, 'len: get utf8 scalar length correctly';
 }