VCP::Dest - A base class for VCP destinations

These methods are intended to support subclasses.

digest

    $self->digest( "/tmp/readers" ) ;

Returns the Base64 MD5 digest of the named file. Used to compare a base rev (which is the revision *before* the first one we want to transfer) of a file from the source repo to the existing head rev of a dest repo. The Base64 version is returned because that's what RevML uses and we might want to cross-check with a .revml file when debugging.

compare_base_revs

   $self->compare_base_revs( $rev, $work_path ) ;

Checks out the indicated revision from the destination repository and compares it (using digest()) to the file from the source repository (as indicated by CW$work_path). Dies with an error message if the base revisions do not match. Calls CW$self->checkout_file( CW$rev ), which the subclass must implement.

header

Gets/sets the CW$header data structure passed to handle_header().

rev_map

Returns a reference to the RevMapDB for this backend and repository. Creates an empty one if need be.

head_revs

Returns a reference to the HeadRevsDB for this backend and repository. Creates an empty one if need be.

main_branch_id

Returns a reference to the MainBranchIdDB for this backend and repository. Creates an empty one if need be.

files

Returns a reference to the FilesDB for this backend and repository. Creates an empty one if need be.

These methods are overloaded by subclasses.

backfill

   $dest->backfill( $rev ) ;

Checks the file indicated by VCP::Rev CW$rev out of the target repository if this destination supports backfilling. Currently, only the revml and the reporting & debugging destinations do not support backfilling. The CW$rev->workpath must be set to the filename the backfill was put in. This is used when doing an incremental update, where the first revision of a file in the update is encoded as a delta from the prior version. A digest of the prior version is sent along before the first version delta to verify it's presence in the database. So, the source calls backfill(), which returns TRUE on success, FALSE if the destination doesn't support backfilling, and dies if there's an error in procuring the right revision. If FALSE is returned, then the revisions will be sent through with no working path, but will have a delta record. MUST BE OVERRIDDEN.

sort_filter

    sub sort_filter {
       my $self = shift;
       my @sort_keys = @_;
       return () if @sort_keys && $sort_keys[0] eq "change_id";
       require VCP::Filter::changesets;
       return ( VCP::Filter::changesets->new(), );
    }

This is passed a sort specification string and returns any filters needed to presort data for this destination. It may return the empty list (the default), or one or more instantiated filters.

require_change_id_sort

Destinations that care about the sort order usually want to use the changesets filter, so they can overload the sort filter like so:

   sub sort_filters { shift->require_change_id_sort( @_ ) }

handle_footer

   $dest->handle_footer( $footer ) ;

Does any cleanup necessary. Not required. Don't call this from the override.

handle_header

   $dest->handle_header( $header ) ;

Stows CW$header in CW$self->header. This should only rarely be overridden, since the first call to handle_rev() should output any header info.

rev_count

   $dest->rev_count( $number_of_revs_forthcoming );

Sent by the last aggregating plugin in the filter chain just before the first revision is sent to inform us of the number of revs to expect.

skip_rev

Sent by filters that discard revisions in line.

handle_rev

   $dest->handle_rev( $rev ) ;

Outputs the item referred to by VCP::Rev CW$rev. If this is the first call, then CW$self->none_seen will be TRUE and any preamble should be emitted. MUST BE OVERRIDDEN. Don't call this from the override.

last_rev_in_filebranch

   my $rev_id = $dest->last_rev_in_filebranch(
      $source_repo_id,
      $source_filebranch_id
   );

Returns the last revision for the file and branch indicated by CW$source_filebranch_id. This is used to support --continue. Returns undef if not found.

Several fields are jury rigged for base revisions: these are fake revisions used to start off incremental, non-bootstrap transfers with the MD5 digest of the version that must be the last version in the target repository. Since these are faked, they don't contain comments or timestamps, so the comment and timestamp fields are treated as "" and 0 by the sort routines.

Copyright 2000, Perforce Software, Inc. All Rights Reserved.

This module and the VCP package are licensed according to the terms given in the file LICENSE accompanying this distribution, a copy of which is included in vcp.

Barrie Slaymaker <barries@slaysys.com>