transaction: add support for non-append files...
transaction: add support for non-append files
This adds support for normal, non-append-only files in transactions. For
example, .hg/store/fncache and .hg/store/phaseroots should be written as part of
the transaction, but are not append only files.
This adds a journal.backupfiles along side the normal journal. This tracks which
files have been backed up as part of the transaction. transaction.addbackup()
creates a backup of the file (using a hardlink), which is later used to recover
in the event of the transaction failing.
Using a seperate journal allows the repository to still be used by older
versions of Mercurial. A future patch will use this functionality and add tests
for it.
