playground refactoring: Dgit.pm: Honour $maindir in fresh_playground

[dgit.git] / Debian / Dgit.pm

diff --git a/Debian/Dgit.pm b/Debian/Dgit.pm
index 1f9c8276257b8999e8a28075511fca6fea89a544..473c01e6018bc19c2eb1878274db0676cc854367 100644 (file)
--- a/Debian/Dgit.pm
+++ b/Debian/Dgit.pm
@@ -44,7 +44,7 @@ BEGIN {
                      server_branch server_ref
                       stat_exists link_ltarget
                      hashfile
-                      fail ensuredir executable_on_path
+                      fail ensuredir must_getcwd executable_on_path
                       waitstatusmsg failedcmd_waitstatus
                      failedcmd_report_cmd failedcmd
                       runcmd cmdoutput cmdoutput_errok
@@ -59,12 +59,14 @@ BEGIN {
                       $debugprefix *debuglevel *DEBUG
                       shellquote printcmd messagequote
                       $negate_harmful_gitattrs
-                     git_slurp_config_src
-                     workarea_setup
-                     fresh_workarea in_workarea);
+                     changedir git_slurp_config_src
+                     playtree_setup);
     # implicitly uses $main::us
-    %EXPORT_TAGS = ( policyflags => [qw(NOFFCHECK FRESHREPO NOCOMMITCHECK)] );
-    @EXPORT_OK   = ( qw($wa), @{ $EXPORT_TAGS{policyflags} } );
+    %EXPORT_TAGS = ( policyflags => [qw(NOFFCHECK FRESHREPO NOCOMMITCHECK)],
+                    playground => [qw(record_maindir $maindir $local_git_cfg
+                                      fresh_playground $playground)]);
+    @EXPORT_OK   = ( @{ $EXPORT_TAGS{policyflags} },
+                    @{ $EXPORT_TAGS{playground} } );
 }
 
 our @EXPORT_OK;
@@ -224,6 +226,12 @@ sub ensuredir ($) {
     die "mkdir $dir: $!";
 }
 
+sub must_getcwd () {
+    my $d = getcwd();
+    defined $d or fail "getcwd failed: $!";
+    return $d;
+}
+
 sub executable_on_path ($) {
     my ($program) = @_;
     return 1 if $program =~ m{/};
@@ -420,6 +428,12 @@ sub is_fast_fwd ($$) {
     }
 }
 
+sub changedir ($) {
+    my ($newdir) = @_;
+    printdebug "CD $newdir\n";
+    chdir $newdir or confess "chdir: $newdir: $!";
+}
+
 sub git_slurp_config_src ($) {
     my ($src) = @_;
     # returns $r such that $r->{KEY}[] = VALUE
@@ -444,10 +458,81 @@ sub git_slurp_config_src ($) {
     return $r;
 }
 
-sub workarea_setup ($) {
-    # for use in the workarea
+# ========== playground handling ==========
+
+# terminology:
+#
+#   $maindir      user's git working tree
+#   $playground   area in .git/ where we can make files, unpack, etc. etc.
+#   playtree      git working tree sharing object store with the user's
+#                 inside playground, or identical to it
+#
+# other globals
+#
+#   $local_git_cfg    hash of arrays of values: git config from $maindir
+#
+# expected calling pattern
+#
+#  firstly
+#
+#    [record_maindir]
+#      must be run in directory containing .git
+#      assigns to $maindir if not already set
+#      also calls git_slurp_config_src to record git config
+#        in $local_git_cfg, unless it's already set
+#
+#    fresh_playground SUBDIR_PATH_COMPONENTS
+#      e.g fresh_playground 'dgit/unpack' ('.git/' is implied)
+#      default SUBDIR_PATH_COMPONENTS is $playground_subdir
+#      calls record_maindir
+#      sets up a new playground (destroying any old one)
+#      assigns to $playground and returns the same pathname
+#      caller may call multiple times with different subdir paths
+#       createing different playgrounds; but $playground global can
+#       refer only to one, obv.
+#
+#  then can use
+#
+#    changedir $playground
+#    changedir $maindir
+#
+#    playtree_setup $local_git_cfg
+#            # ^ call in some (perhaps trivial) subdir of $playground
+#
+#    rmtree $playground
+
+# ----- maindir -----
+
+our $maindir;
+our $local_git_cfg;
+
+sub record_maindir () {
+    $maindir //= must_getcwd();
+    $local_git_cfg //= git_slurp_config_src 'local';
+}
+
+# ----- playgrounds -----
+
+our $playground;
+
+sub fresh_playground ($) {
+    my ($spc) = @_;
+    record_maindir();
+    $spc = ".git/$spc";
+    my $parent = dirname $spc;
+    mkdir $parent or $!==EEXIST or fail "failed to mkdir $parent: $!";
+    rmtree $spc;
+    mkdir $spc or die "$spc $!";
+    return $playground = "$maindir/$spc";
+}
+
+# ----- playtrees -----
+
+sub playtree_setup (;$) {
     my ($t_local_git_cfg) = @_;
-    # should be run in a directory .git/FOO/BAR of a working tree
+    $t_local_git_cfg //= $local_git_cfg;
+    # for use in the playtree
+    # $maindir must be set, eg by calling record_maindir or fresh_playground
     runcmd qw(git init -q);
     runcmd qw(git config gc.auto 0);
     foreach my $copy (qw(user.email user.name user.useConfigOnly
@@ -459,38 +544,11 @@ sub workarea_setup ($) {
        runcmd qw(git config), $copy, $_ foreach @$v;
     }
     rmtree('.git/objects');
-    symlink '../../../../objects','.git/objects' or die $!;
+    symlink "$maindir/.git/objects",'.git/objects' or die $!;
     ensuredir '.git/info';
     open GA, "> .git/info/attributes" or die $!;
     print GA "* $negate_harmful_gitattrs\n" or die $!;
     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;