Simon Sapin <simon.sapin@octobus.net> [Tue, 13 Jul 2021 17:18:23 +0200] rev 47678
dirstate-v2: Support appending to the same data file
For now we’re still writing the entire data every time, so appending is not
useful yet. Later we’ll have new nodes pointing to some existing data for
nodes and paths that haven’t changed.
The decision whether to append is pseudo-random in order to make tests exercise
both code paths. This will be replaced by a heuristic based on the amount
of unused existing data.
Differential Revision: https://phab.mercurial-scm.org/D11094
Simon Sapin <simon.sapin@octobus.net> [Tue, 13 Jul 2021 09:44:44 +0200] rev 47677
dirstate-v2: shrink on-disk path lengths to 16-bits
Differential Revision: https://phab.mercurial-scm.org/D11091
Simon Sapin <simon.sapin@octobus.net> [Mon, 12 Jul 2021 23:05:56 +0200] rev 47676
dirstate-v2: Rename Header to Root, move it to the end of the data file
Now that they don’t have to be at the start, a given data file may contain
multiple "roots". A docket only points to one of them, and previous ones
are left unused to allow allow append-only in-place writing to an existing
data file.
Differential Revision: https://phab.mercurial-scm.org/D11090
Simon Sapin <simon.sapin@octobus.net> [Mon, 12 Jul 2021 22:46:52 +0200] rev 47675
dirstate-v2: Enforce data size read from the docket file
The data file may not be shorter than its size given by the docket.
It may be longer, but additional data is ignored.
Differential Revision: https://phab.mercurial-scm.org/D11089
Simon Sapin <simon.sapin@octobus.net> [Thu, 08 Jul 2021 12:18:21 +0200] rev 47674
dirstate-v2: Introduce a docket file
.hg/dirstate now only contains some metadata to point to a separate data file
named .hg/dirstate.{}.d with a random hexadecimal identifier. For now every
update creates a new data file and removes the old one, but later we’ll
(usually) append to an existing file.
Separating into two files allows doing the "write to a temporary file then
atomically rename into destination" dance with only a small docket file,
without always rewriting a lot of data.
Differential Revision: https://phab.mercurial-scm.org/D11088
Pierre-Yves David <pierre-yves.david@octobus.net> [Thu, 15 Jul 2021 17:24:09 +0200] rev 47673
dirstate: replace a dead conditional branch with an assert in `update_file`
This is a case we never meet, so lets trim it away to simplify the code before
more changes.
Differential Revision: https://phab.mercurial-scm.org/D11128