exchange: support sorting URLs by client-side preferences
Not all bundles are appropriate for all clients. For example, someone
with a slow Internet connection may want to prefer bz2 bundles over gzip
bundles because they are smaller and don't take as long to transfer.
This is information that a server cannot know on its own. So, we invent
a mechanism for "preferring" server-advertised URLs based on their
attributes.
We could invent a negotiation between client and server where the client
sends its preferences and the sorting/filtering is done server-side.
However, this feels complex. We can avoid complicating the wire protocol
and exposing ourselves to backwards compatible concerns by performing
the sorting locally.
This patch defines a new config option for expressing preferred
attributes in server-advertised bundles.
At Mozilla, we leverage this feature so clients in fast data centers
prefer uncompressed bundles. (We advertise gzip bundles first because
that is a reasonable default.)
I consider this an advanced feature. I'm on the fence as to whether it
should be documented in `hg help config`.
$ hg init repo
$ cd repo
$ i=0; while [ "$i" -lt 213 ]; do echo a >> a; i=`expr $i + 1`; done
$ hg add a
$ cp a b
$ hg add b
Wide diffstat:
$ hg diff --stat
a | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
b | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 426 insertions(+), 0 deletions(-)
diffstat width:
$ COLUMNS=24 hg diff --config ui.interactive=true --stat
a | 213 ++++++++++++++
b | 213 ++++++++++++++
2 files changed, 426 insertions(+), 0 deletions(-)
$ hg ci -m adda
$ cat >> a <<EOF
> a
> a
> a
> EOF
Narrow diffstat:
$ hg diff --stat
a | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
$ hg ci -m appenda
>>> open("c", "wb").write("\0")
$ touch d
$ hg add c d
Binary diffstat:
$ hg diff --stat
c | Bin
1 files changed, 0 insertions(+), 0 deletions(-)
Binary git diffstat:
$ hg diff --stat --git
c | Bin
d | 0
2 files changed, 0 insertions(+), 0 deletions(-)
$ hg ci -m createb
>>> open("file with spaces", "wb").write("\0")
$ hg add "file with spaces"
Filename with spaces diffstat:
$ hg diff --stat
file with spaces | Bin
1 files changed, 0 insertions(+), 0 deletions(-)
Filename with spaces git diffstat:
$ hg diff --stat --git
file with spaces | Bin
1 files changed, 0 insertions(+), 0 deletions(-)
diffstat within directories:
$ hg rm -f 'file with spaces'
$ mkdir dir1 dir2
$ echo new1 > dir1/new
$ echo new2 > dir2/new
$ hg add dir1/new dir2/new
$ hg diff --stat
dir1/new | 1 +
dir2/new | 1 +
2 files changed, 2 insertions(+), 0 deletions(-)
$ hg diff --stat --root dir1
new | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
$ hg diff --stat --root dir1 dir2
warning: dir2 not inside relative root dir1
$ hg diff --stat --root dir1 -I dir1/old
$ cd dir1
$ hg diff --stat .
dir1/new | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
$ hg diff --stat --root .
new | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
$ hg diff --stat --root ../dir1 ../dir2
warning: ../dir2 not inside relative root . (glob)
$ hg diff --stat --root . -I old
$ cd ..