1 files changed, 106 insertions, 0 deletions
diff --git a/scripts/checkout_layer_hash.sh b/scripts/checkout_layer_hash.sh
new file mode 100755
index 0000000..93299d8
--- /dev/null
+++ b/scripts/checkout_layer_hash.sh
@@ -0,0 +1,106 @@
+#!/bin/sh
+# (C) Gunnar Andersson 2015-12-12
+# License: MPLv2
+
+# This fetches information about layer dependencies
+# as documented in meta-ivi README.
+# revision, branch name, or sub layer name can be extracted
+
+README=README.md
+DEBUG=false
+
+
+fail() {
+   echo "*** FAILED ***"
+   [ -n "$1" ] && echo "Message: " $@
+   exit 1
+}
+
+sanity_check_num_lines() {
+   what=$1 ; min=$2 ; max=$3
+
+   numlines="$(wc -l)" # < Reads from stdin
+
+   if [ $numlines -lt $min ] ; then 
+      fail "Sanity check: It looks like section $what has $numlines lines, and that is not enough.  Please check what is wrong."
+   fi
+
+   if [ $numlines -gt $max ] ; then
+      fail "Sanity check: It looks like section $what has $numlines lines, and that is more than expected.  Please check what is wrong."
+   fi
+}
+
+[ -f ./$README ] || fail "Cannot find README.md.  (Current directory is $PWD)"
+
+get_layer_info() {
+   layer=$1
+   what=$2
+
+   # Example README format:
+   #
+   #Layer Dependencies
+   #------------------
+   #
+   #URI: git://git.yoctoproject.org/poky
+   #> branch:   fido
+   #> revision: eb4a134a60e3ac26a48379675ad6346a44010339
+   #
+   #URI: git://git.openembedded.org/meta-openembedded
+   #> layer:    meta-oe
+   #> branch:   fido
+   #> revision: 5b0305d9efa4b5692cd942586fb7aa92dba42d59
+
+   # Extract relevant section of the README
+   dependency_section=$( <$README \
+      sed -n '/Layer Dependencies/,/known to work/p' |\
+      egrep 'URI:|branch:|layer:|revision:')
+
+   # Debug printouts...
+   $DEBUG && echo "OK, found the following layer info in dependency section:"
+   $DEBUG && cat <<EOT
+   $dependency_section
+EOT
+
+   cat <<EOT | sanity_check_num_lines "Layer Dependencies Section" 6 20
+   $dependency_section
+EOT
+
+   # Get only this layer's information
+   layer_info=$(
+   cat <<EOT | sed -n "/URI:.*$layer/,/URI:/p" | sed 's/> //' | head -4
+   $dependency_section
+EOT
+   )
+
+   # Get value for item "what" (what = revision, branch, ...)
+   value=$(
+   cat <<EOT | grep "$what" | awk '{print $2}'
+   $layer_info
+EOT
+   )
+
+   # Check again - now only one line expected...
+   cat <<EOT | sanity_check_num_lines "$what information for $layer" 1 1
+   $value
+EOT
+
+   # OK, this should be it
+   echo $value
+
+}
+
+checkoutlayer=$1
+[ -z "$checkoutlayer" ] && { echo "Usage: $0 <layername, e.g. poky>" ; exit 1 ; }
+
+# Extract revision from README in meta-ivi
+revision=$(get_layer_info $checkoutlayer revision)
+
+# Fail if we could not fetch revision
+[ -z "$revision" ] && fail "Revision extracted from README was empty"
+
+# Checkout the right revision in this layer.  We expect the layer, e.g.
+# poky to be found inside the root of meta-ivi, that is the $PWD when
+# this script is run.  (Not true on full system builds, but typically
+# when building baseline only)
+cd ../"$checkoutlayer" || fail "Can't cd to layer directory ($checkoutlayer)"
+git checkout $revision