add checkout verb, to make bite-sized git repos

This allows you to create a repo as a child of asp's, which you can
modify as you wish, and continue to pull changes from after calling
'abs update'. One might create a new remote for this repo in which
to publish their own downstream branch.

4 files changed, 31 insertions, 1 deletions

diff --git a/README.md b/README.md
index 2671a9f..177d8ff 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,12 @@ Get the source files for some packages:
 asp export pacman testing/systemd extra/pkgfile
 ~~~
 
+Get a fully functional git checkout of a single package:
+
+~~~
+asp checkout pkgfile
+~~~
+
 List the repositories a package has been pushed to:
 
 ~~~
diff --git a/asp.in b/asp.in
index fcf16b0..0797bc9 100644
--- a/asp.in
+++ b/asp.in
@@ -264,6 +264,9 @@ case $action in
     usage
     exit 0
     ;;
+  checkout)
+    map package_checkout "$@"
+    ;;
   '')
     log_fatal 'no action specified (use -h for help)'
     ;;
diff --git a/man/asp.1.txt b/man/asp.1.txt
index f94fe8c..c318d3c 100644
--- a/man/asp.1.txt
+++ b/man/asp.1.txt
@@ -23,12 +23,20 @@ Commands
 --------
 The following commands are understood:
 
+*checkout*::
+	Create a new git repository containing the full source and history
+	for each of the given targets. The new repository will pull from the
+	repository in '$ASPROOT' and must be updated separately after using
+	'abs update'. If a checkout occurs on the same filesystem as '$ASPROOT',
+	most of the metadata can be hard linked, making this a relatively cheap
+	copy.
+
 *difflog*::
 	Show the full revision history of the target, with file diffs.
 
 *export*::
 	Dump the build source files for each target into a directory of the
-	target's name in $PWD. Targets can be specified simply as 'package' to
+	target's name in '$PWD'. Targets can be specified simply as 'package' to
 	check out the source files at HEAD, or in 'repository/package' format
 	to checkout the source files which were used to push the 'package' which
 	exists in 'repository'.
diff --git a/package.inc.sh b/package.inc.sh
index f6059e4..63b968a 100644
--- a/package.inc.sh
+++ b/package.inc.sh
@@ -91,6 +91,19 @@ package_export() {
       bsdtar -C "$startdir" -s ",^$subtree/,$pkgname/," -xf - "$subtree/"
 }
 
+package_checkout() {
+  local pkgname=$1 remote
+
+  package_init "$pkgname" remote || return 1
+
+  # create a local tracking branch to clone from. ignore errors because
+  # it might already exist.
+  git branch "$remote/packages/$pkgname" "$remote/packages/$pkgname" 2>/dev/null
+
+  git clone "$ASPROOT" --single-branch --branch "$remote/packages/$pkgname" \
+    "$startdir/$pkgname"
+}
+
 package_get_repos_with_arch() {
   local pkgname=$1 remote=$2
   local objtype path arch repo