Dpkg::File: Make file_slurp() also accept pathnames in addition to filehandles

This makes several call sites more clear, as we move the logic inside
the function.

6 files changed, 23 insertions, 18 deletions

diff --git a/debian/changelog b/debian/changelog
index 9a6e7a47d..64380eb07 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -4,6 +4,8 @@ dpkg (1.19.3) UNRELEASED; urgency=medium
   * Perl modules:
     - Dpkg::Changelog::Debian: Preserve modelines at EOF. Closes: #916056
       Thanks to Chris Lamb <lamby@debian.org> for initial test cases.
+    - Dpkg::File: Make file_slurp() also accept pathnames in addition to
+      filehandles.
   * Documentation:
     - dpkg(1): Clarify --remove action. Closes: #914478
     - dpkg-query(1): Clarify --list option behavior when no arguments are
diff --git a/scripts/Dpkg/File.pm b/scripts/Dpkg/File.pm
index 884923852..6ba49a6e6 100644
--- a/scripts/Dpkg/File.pm
+++ b/scripts/Dpkg/File.pm
@@ -25,12 +25,26 @@ our @EXPORT = qw(
 );
 
 use Exporter qw(import);
+use Scalar::Util qw(openhandle);
+
+use Dpkg::ErrorHandling;
+use Dpkg::Gettext;
 
 sub file_slurp {
-    my $fh = shift;
+    my $file = shift;
+    my $fh;
+    my $doclose = 0;
 
+    if (openhandle($file)) {
+        $fh = $file;
+    } else {
+        open $fh, '<', $file or syserr(g_('cannot read %s'), $fh);
+        $doclose = 1;
+    }
     local $/;
     my $data = <$fh>;
+    close $fh if $doclose;
+
     return $data;
 }
 
diff --git a/scripts/Dpkg/Source/Package/V2.pm b/scripts/Dpkg/Source/Package/V2.pm
index fe9a1727d..e2c1b49fb 100644
--- a/scripts/Dpkg/Source/Package/V2.pm
+++ b/scripts/Dpkg/Source/Package/V2.pm
@@ -591,12 +591,8 @@ sub _get_patch_header {
     unless (-f $ph) {
         $ph = File::Spec->catfile($dir, 'debian', 'source', 'patch-header');
     }
-    my $text;
     if (-f $ph) {
-        open(my $ph_fh, '<', $ph) or syserr(g_('cannot read %s'), $ph);
-        $text = file_slurp($ph_fh);
-        close($ph_fh);
-        return $text;
+        return file_slurp($ph);
     }
     my $ch_info = changelog_parse(offset => 0, count => 1,
         file => File::Spec->catfile($dir, 'debian', 'changelog'));
@@ -613,6 +609,7 @@ it.\n";
     $header->{'Author'} = $ch_info->{'Maintainer'};
     my $yyyy_mm_dd = POSIX::strftime('%Y-%m-%d', gmtime);
 
+    my $text;
     $text = "$header";
     run_vendor_hook('extend-patch-header', \$text, $ch_info);
     $text .= "\n---
diff --git a/scripts/dpkg-genchanges.pl b/scripts/dpkg-genchanges.pl
index 13ab8a453..690a4e59d 100755
--- a/scripts/dpkg-genchanges.pl
+++ b/scripts/dpkg-genchanges.pl
@@ -415,10 +415,7 @@ foreach (keys %{$changelog}) {
 }
 
 if ($changesdescription) {
-    open(my $changes_fh, '<', $changesdescription)
-        or syserr(g_('cannot read %s'), $changesdescription);
-    $fields->{'Changes'} = "\n" . file_slurp($changes_fh);
-    close($changes_fh);
+    $fields->{'Changes'} = "\n" . file_slurp($changesdescription);
 }
 
 for my $p (keys %p2f) {
diff --git a/scripts/t/Dpkg_Changelog.t b/scripts/t/Dpkg_Changelog.t
index f487ff560..4d046fec1 100644
--- a/scripts/t/Dpkg_Changelog.t
+++ b/scripts/t/Dpkg_Changelog.t
@@ -41,9 +41,7 @@ foreach my $file ("$datadir/countme", "$datadir/shadow", "$datadir/fields",
     my $changes = Dpkg::Changelog::Debian->new(verbose => 0);
     $changes->load($file);
 
-    open(my $clog_fh, '<', "$file") or die "can't open $file\n";
-    my $content = file_slurp($clog_fh);
-    close($clog_fh);
+    my $content = file_slurp($file);
     cmp_ok($content, 'eq', "$changes", "string output of Dpkg::Changelog on $file");
 
     my $errors = $changes->get_parse_errors();
diff --git a/utils/t/update_alternatives.t b/utils/t/update_alternatives.t
index 491fee07d..84e2080da 100644
--- a/utils/t/update_alternatives.t
+++ b/utils/t/update_alternatives.t
@@ -21,6 +21,7 @@ use Test::More;
 use File::Spec;
 
 use Dpkg::IPC;
+use Dpkg::File qw(file_slurp);
 use Dpkg::Path qw(find_command);
 
 my $srcdir = $ENV{srcdir} || '.';
@@ -260,11 +261,7 @@ check_choice(0, 'auto', 'initial install 3');
 
 # verify that the administrative file is sorted properly
 {
-    local $/ = undef;
-    open(my $db_fh, '<', "$admindir/generic-test") or die $!;
-    my $content = <$db_fh>;
-    close($db_fh);
-
+    my $content = file_slurp("$admindir/generic-test");
     my $expected =
 "auto
 $bindir/generic-test