The current UI around alternates is lacking. There are commands to add an alternate at the time of a clone (e.g. 'git clone --reference') but no commands to see what alternates have been configured or to add an alternate after a repository has been cloned. This patch adds a friendlier UI for displaying and configuring alternates.
Signed-off-by: Chris Packham <judge.packham@gmail.com>
---
Makefile | 1 +
git-alternate.sh | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 157 insertions(+), 0 deletions(-)
create mode 100755 git-alternate.sh
diff --git a/Makefile b/Makefile
index 3a6c6ea..0dc5e42 100644
--- a/Makefile
+++ b/Makefile
@@ -334,6 +334,7 @@ TEST_PROGRAMS_NEED_X =
unexport CDPATH
SCRIPT_SH += git-am.sh
+SCRIPT_SH += git-alternate.sh
SCRIPT_SH += git-bisect.sh
SCRIPT_SH += git-difftool--helper.sh
SCRIPT_SH += git-filter-branch.sh
diff --git a/git-alternate.sh b/git-alternate.sh
new file mode 100755
index 0000000..ea9925b
--- /dev/null
+++ b/git-alternate.sh
@@ -0,0 +1,156 @@
+#!/bin/sh
+#
+# This file is licensed under the GPL v2
+#
+# Copyright (c) Chris Packham
+
+dashless=$(basename "$0" | sed -e 's/-/ /')
+OPTIONS_KEEPDASHDASH=
+OPTIONS_SPEC="\
+$dashless [-r|--recursive]
+$dashless [-a|--add <dir>]
+$dashless [-f|--force] [-d|delete <dir>]
+--
+r,recursive recursively follow alternates
+a,add= add dir as an alternate
+d,del= delete dir as an alternate
+f,force force a delete operation
+"
+. git-sh-setup
+
+#
+# Given the path in $1, which may or may not be a relative path,
+# convert it to an absolute path
+#
+abspath()
+{
+ cd "$1"
+ pwd
+ cd - > /dev/null
+}
+
+#
+# Runs through the alternates file calling the callback function $1
+# with the name of the alternate as the first argument to the callback
+# any additional arguments are passed to the callback function.
+#
+walk_alternates()
+{
+ alternates=$GIT_DIR/objects/info/alternates
+ callback=$1
+ shift
+
+ if test -f "$alternates"
+ then
+ while read line
+ do
+ $callback "$line" "$@"
+ done< "$alternates"
+ fi
+}
+
+#
+# Walk function to display one alternate object store and, if the user
+# has specified -r, recursively call show_alternates on the git
+# repository that the object store belongs to.
+#
+show_alternates_walk()
+{
+ say "Object store $1"
+ say " referenced via $GIT_DIR"
+
+ new_git_dir=${line%%/objects}
+ if test "$recursive" = "true" && test "$GIT_DIR" != "$new_git_dir"
+ then
+ (
+ export GIT_DIR=$new_git_dir
+ show_alternates
+ )
+ fi
+}
+
+# Display alternates currently configured
+show_alternates()
+{
+ walk_alternates show_alternates_walk
+}
+
+#
+# Walk function to check that the specified alternate does not
+# already exist.
+#
+check_current_alternate_walk()
+{
+ if test "$1" = "$2"; then
+ die "fatal: Object store $2 is already used by $GIT_DIR"
+ fi
+}
+
+# Add a new alternate
+add_alternate()
+{
+ if test ! -d "$dir"; then
+ die "fatal: $dir is not a directory"
+ fi
+
+ abs_dir=$(abspath "$dir")
+ walk_alternates check_current_alternate_walk "$abs_dir"
+
+ # At this point we know that $dir is a directory that exists
+ # and that its not already being used as an alternate. We could
+ # go further and verify that $dir has valid objects.
+
+ # if we're still going we can safely add the alternate
+ echo "$abs_dir" >> $GIT_DIR/objects/info/alternates
+ say "$abs_dir added as an alternate"
+ say " use 'git repack -adl' to remove duplicate objects"
+}
+
+# Deletes the name alternate from the alternates file.
+# If there are no more alternates the alternates file will be removed
+del_alternate()
+{
+ if test ! $force = "true"; then
+ say "Not forced, use"
+ say " 'git repack -a' to fetch missing objects, then "
+ say " '$dashless -f -d \"$dir\"' to remove the alternate"
+ die
+ fi
+
+ alternates=$GIT_DIR/objects/info/alternates
+ new_alternates=$alternates.tmp
+
+ grep -v -F "$dir" <"$alternates" >"$new_alternates"
+ if test -s "$new_alternates"
+ then
+ mv "$new_alternates" "$alternates"
+ else
+ # save the git from repeatedly reading a 0 length file
+ rm -f "$alternates" "$new_alternates"
+ fi
+}
+
+dir=""
+oper=""
+force="false"
+
+# Option parsing
+while test $# != 0
+do
+ case "$1" in
+ -r|--recursive) recursive="true" ;;
+ -a|--add) oper="add"; dir="$2"; shift ;;
+ -d|--delete) oper="del"; dir="$2"; shift ;;
+ -f|--force) force="true" ;;
+ --) shift; break ;;
+ *) usage ;;
+ esac
+ shift
+done
+
+# Now go and do it
+case "$oper" in
+ add) add_alternate ;;
+ del) del_alternate ;;
+ *) show_alternates ;;
+esac
--
1.7.0.3
Chris Packham