1 files changed, 28 insertions, 0 deletions
diff --git a/scripts/clang-format-diff.sh b/scripts/clang-format-diff.sh
new file mode 100755
index 000000000..2525259e9
--- /dev/null
+++ b/scripts/clang-format-diff.sh
@@ -0,0 +1,28 @@
+#!/bin/bash
+
+set -o errexit
+
+# When we are running on travis and *not* part of a pull request we don't
+# have any upstream branch to compare against.
+if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then
+  echo "Skipping since not running on travis PR"
+  exit 0
+fi
+
+if [ -n "$TRAVIS_BRANCH" ]; then
+  BRANCH=$TRAVIS_BRANCH
+else
+  BRANCH=origin/master
+fi
+
+MERGE_BASE=$(git merge-base $BRANCH HEAD)
+FORMAT_MSG=$(git clang-format $MERGE_BASE -q --diff -- src/)
+if [ -n "$FORMAT_MSG" -a "$FORMAT_MSG" != "no modified files to format" ]
+then
+  echo "Please run git clang-format before committing, or apply this diff:"
+  echo
+  # Run git clang-format again, this time without capruting stdout.  This way
+  # clang-format format the message nicely and add color.
+  git clang-format $MERGE_BASE -q --diff -- src/
+  exit 1
+fi