branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
Some commands allow the user to specify a date, e.g.:
- backout, commit, import, tag: Specify the commit date.
- log, revert, update: Select revision(s) by date.
Many date formats are valid. Here are some examples:
- ``Wed Dec 6 13:18:29 2006`` (local timezone assumed)
- ``Dec 6 13:18 -0600`` (year assumed, time offset provided)
- ``Dec 6 13:18 UTC`` (UTC and GMT are aliases for +0000)
- ``Dec 6`` (midnight)
- ``13:18`` (today assumed)
- ``3:39`` (3:39AM assumed)
- ``3:39pm`` (15:39)
- ``2006-12-06 13:18:29`` (ISO 8601 format)
- ``2006-12-6 13:18``
- ``2006-12-6``
- ``12-6``
- ``12/6``
- ``12/6/6`` (Dec 6 2006)
- ``today`` (midnight)
- ``yesterday`` (midnight)
- ``now`` - right now
Lastly, there is Mercurial's internal format:
- ``1165411109 0`` (Wed Dec 6 13:18:29 2006 UTC)
This is the internal representation format for dates. The first number
is the number of seconds since the epoch (1970-01-01 00:00 UTC). The
second is the offset of the local timezone, in seconds west of UTC
(negative if the timezone is east of UTC).
The log command also accepts date ranges:
- ``<DATE`` - at or before a given date/time
- ``>DATE`` - on or after a given date/time
- ``DATE to DATE`` - a date range, inclusive
- ``-DAYS`` - within a given number of days from today