Add vendor hook to register custom fields

scripts/Dpkg/Control/Fields.pm

@@ -24,6 +24,7 @@ use Dpkg::Gettext;
 use Dpkg::ErrorHandling;
 use Dpkg::Control::Types;
 use Dpkg::Checksums qw(@check_supported %check_supported);
+use Dpkg::Vendor qw(run_vendor_hook);
 
 our @EXPORT = qw(field_capitalize field_is_official field_is_allowed_in
                  field_transfer_single field_transfer_all
@@ -313,6 +314,20 @@ $FIELD_ORDER{CTRL_APT_SRC()} = [ @{$FIELD_ORDER{CTRL_PKG_SRC()}} ];
                                   @{$FIELD_ORDER{CTRL_PKG_SRC()}};
 &field_insert_before(CTRL_APT_SRC, "Checksums-Md5", "Directory");
 
+# Register vendor specifics fields
+foreach my $op (run_vendor_hook("register-custom-fields")) {
+    my $func = shift @$op;
+    if ($func eq "register") {
+        &field_register(@$op);
+    } elsif ($func eq "insert_before") {
+        &field_insert_before(@$op);
+    } elsif ($func eq "insert_after") {
+        &field_insert_after(@$op);
+    } else {
+        error("vendor hook register-custom-fields sent bad data: @$op");
+    }
+}
+
 =head1 NAME
 
 Dpkg::Control::Fields - manage (list of official) control fields

scripts/Dpkg/Vendor.pm

@@ -21,7 +21,7 @@ use warnings;
 
 use Dpkg::ErrorHandling;
 use Dpkg::Gettext;
-use Dpkg::Control;
+use Dpkg::Control::Hash;
 
 use base qw(Exporter);
 our @EXPORT_OK = qw(get_vendor_info get_current_vendor get_vendor_file
@@ -62,7 +62,7 @@ sub get_vendor_info(;$) {
     my $file = get_vendor_file($vendor);
     return undef unless $file;
     open(my $fh, "<", $file) || syserr(_g("cannot read %s"), $file);
-    my $fields = Dpkg::Control->new(type => CTRL_FILE_VENDOR);
+    my $fields = Dpkg::Control::Hash->new();
     $fields->parse_fh($fh, $file) || error(_g("%s is empty"), $file);
     close($fh);
     return $fields;

scripts/Dpkg/Vendor/Default.pm

@@ -85,6 +85,17 @@ The hook is called when dpkg-source is checking a signature on a source
 package. It takes no parameters, but returns a (possibly empty) list of
 vendor-specific keyrings.
 
+=item register-custom-fields ()
+
+The hook is called in Dpkg::Control::Fields to register custom fields.
+You should return a list of arrays. Each array is an operation to perform.
+The first item is the name of the operation and corresponds
+to a field_* function provided by Dpkg::Control::Fields. The remaining
+fields are the parameters that are passed unchanged to the corresponding
+function.
+
+Known operations are "register", "insert_after" and "insert_before".
+
 =back
 
 =cut
@@ -98,6 +109,8 @@ sub run_hook {
         my $fields = shift @params;
     } elsif ($hook eq "keyrings") {
         return ();
+    } elsif ($hook eq "register-custom-fields") {
+        return ();
     }
 }