Add a pre-commit hook to ensure pep8

diff --git a/tools/githook/pre-commit b/tools/githook/pre-commit
new file mode 100755 (executable)
index 0000000..47cc50d
--- /dev/null
+++ b/tools/githook/pre-commit
@@ -0,0 +1,38 @@
+#!/bin/sh
+
+if git rev-parse --verify HEAD >/dev/null 2>&1
+then
+       against=HEAD
+else
+       # Initial commit: diff against an empty tree object
+       against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
+fi
+
+FILES=$(git diff-index --name-only --diff-filter=ACMR --cached $against -- |egrep ".py$")
+if [ "$FILES" != "" ]; then
+    # We want to look at the staged version only, so we have to run it once for
+    # each file.
+    E=0
+    for F in ${FILES}; do
+       P=$(git show ":$F" | python3 -c "import sys; compile(sys.stdin.read(), '/dev/null', 'exec')")
+       if [ "$?" != "0" ]; then
+           echo "Errors in $F"
+           echo $P
+           E=1
+           continue
+       fi
+
+       R=$(git show ":$F" | pep8 -)
+       if [ "$?" != "0" ]; then
+           echo "Errors in $F"
+           echo "$R"
+           E=1
+       fi
+    done
+    if [ "$E" != "0" ]; then
+       exit 1
+    fi
+
+    echo Basic python checks passed.
+fi
+