qerror: add check-qerror.sh to verify alphabetical order

We're supposed to keep qerror definitions and table entries in
alphabetical order.  In practice this is not checked.

I haven't found a nice way to integrate this into the makefile yet but
we can at least have this script which verifies that qerrors are in
alphabetical order.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

qerror.c

@@ -40,8 +40,7 @@ static const QType qerror_type = {
  * "running out of foo: %(foo)%%"
  *
  * Please keep the entries in alphabetical order.
- * Use "sed -n '/^static.*qerror_table\[\]/,/^};/s/QERR_/&/gp' qerror.c | sort -c"
- * to check.
+ * Use scripts/check-qerror.sh to check.
  */
 static const QErrorStringTable qerror_table[] = {
     {

qerror.h

@@ -49,7 +49,7 @@ QError *qobject_to_qerror(const QObject *obj);
 /*
  * QError class list
  * Please keep the definitions in alphabetical order.
- * Use "grep '^#define QERR_' qerror.h | sort -c" to check.
+ * Use scripts/check-qerror.sh to check.
  */
 #define QERR_BAD_BUS_FOR_DEVICE \
     "{ 'class': 'BadBusForDevice', 'data': { 'device': %s, 'bad_bus_type': %s } }"

scripts/check-qerror.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+# This script verifies that qerror definitions and table entries are
+# alphabetically ordered.
+
+check_order() {
+  errmsg=$1
+  shift
+
+  # sort -C verifies order but does not print a message.  sort -c does print a
+  # message.  These options are both in POSIX.
+  if ! "$@" | sort -C; then
+    echo "$errmsg"
+    "$@" | sort -c
+    exit 1
+  fi
+  return 0
+}
+
+check_order 'Definitions in qerror.h must be in alphabetical order:' \
+            grep '^#define QERR_' qerror.h
+check_order 'Entries in qerror.c:qerror_table must be in alphabetical order:' \
+            sed -n '/^static.*qerror_table\[\]/,/^};/s/QERR_/&/gp' qerror.c