Dgit: Introduce in_workarea and fresh_workarea

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Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/Debian/Dgit.pm b/Debian/Dgit.pm
index 3d97848ff2df75b96491a8fc2ac2d6bd5224a86a..1f9c8276257b8999e8a28075511fca6fea89a544 100644 (file)
--- a/Debian/Dgit.pm
+++ b/Debian/Dgit.pm
@@ -30,6 +30,7 @@ use Digest::SHA;
 use Data::Dumper;
 use IPC::Open2;
 use File::Path;
+use File::Basename;
 
 BEGIN {
     use Exporter   ();
@@ -59,10 +60,11 @@ BEGIN {
                       shellquote printcmd messagequote
                       $negate_harmful_gitattrs
                      git_slurp_config_src
-                      workarea_setup);
+                     workarea_setup
+                     fresh_workarea in_workarea);
     # implicitly uses $main::us
     %EXPORT_TAGS = ( policyflags => [qw(NOFFCHECK FRESHREPO NOCOMMITCHECK)] );
-    @EXPORT_OK   = @{ $EXPORT_TAGS{policyflags} };
+    @EXPORT_OK   = ( qw($wa), @{ $EXPORT_TAGS{policyflags} } );
 }
 
 our @EXPORT_OK;
@@ -464,4 +466,31 @@ sub workarea_setup ($) {
     close GA or die $!;
 }
 
+our $wa;
+our $local_git_cfg;
+
+sub in_workarea ($;$) {
+    my $sub = pop @_; # in_workarea [$twa, sub { ... };]
+    # default $twa is global $wa (which caller must, in that case, set)
+    # $twa should be relative paths of the form .git/FOO/BAR
+    my ($twa) = @_;
+    $twa //= $wa;
+    chdir $twa or die "$twa $!";
+    my $r = eval { $sub->($twa); };
+    chdir '../../..' or die "$@; $!";
+    die $@ if length $@;
+    return $r;
+}
+
+sub fresh_workarea (;$) {
+    my ($twa) = @_;
+    $twa //= $wa;
+    $local_git_cfg //= git_slurp_config_src 'local';
+    my $parent = dirname $twa;
+    mkdir $parent or $!==EEXIST or fail "failed to mkdir $parent: $!";
+    rmtree $twa;
+    mkdir $twa or die "$twa $!";
+    in_workarea sub { workarea_setup $local_git_cfg; };
+}
+
 1;