[PATCH v3 2/6] iotests: move check for printable data to QcowHeaderExtension class

[Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>]

Let us differ binary data type from string one for the extension data
variable and keep the string as the QcowHeaderExtension class member
in the script qcow2.py.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
 tests/qemu-iotests/qcow2.py | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/tests/qemu-iotests/qcow2.py b/tests/qemu-iotests/qcow2.py
index e824b09..18e4923 100755
--- a/tests/qemu-iotests/qcow2.py
+++ b/tests/qemu-iotests/qcow2.py
@@ -13,6 +13,12 @@ class QcowHeaderExtension:
     QCOW2_EXT_MAGIC_DATA_FILE = 0x44415441
 
     def __init__(self, magic, length, data):
+        data_str = data[:length]
+        if all(c in string.printable.encode('ascii') for c in data_str):
+            data_str = "'%s'" % data_str.decode('ascii')
+        else:
+            data_str = "<binary>"
+
         if length % 8 != 0:
             padding = 8 - (length % 8)
             data += b"\0" * padding
@@ -21,6 +27,7 @@ class QcowHeaderExtension:
         self.length = length
         self.data = data
         self.name = self.extension_name(magic)
+        self.data_str = data_str
 
     @classmethod
     def create(cls, magic, data):
@@ -162,16 +169,10 @@ class QcowHeader:
     def dump_extensions(self):
         for ex in self.extensions:
 
-            data = ex.data[:ex.length]
-            if all(c in string.printable.encode('ascii') for c in data):
-                data = "'%s'" % data.decode('ascii')
-            else:
-                data = "<binary>"
-
             print("%-25s %s" % ("Header extension:", ex.name))
             print("%-25s %#x" % ("magic", ex.magic))
             print("%-25s %d" % ("length", ex.length))
-            print("%-25s %s" % ("data", data))
+            print("%-25s %s" % ("data", ex.data_str))
             print("")
 
 
-- 
1.8.3.1