PAPI: Add support for format/unformat functions.

With the introduction of new types, like vl_api_address_t
it is now possible to call a message using one of those
functions with a string representation. E.g. for an IP address

ip_add_address(address="1.1.1.1/24")

The language wrapper will automatically convert the string
into the vl_api_address_t representation. Currently
the caller must do the reverse conversion from the returned
named tuple with the unformat function.
rv = get_address_on_interface(sw_if_index=1)
print(VPPFormat.unformat(rv.address))

Change-Id: Ic872b4560b2f4836255bd5260289bfa38c75bc5d
Signed-off-by: Ole Troan <ot@cisco.com>

1 files changed, 144 insertions, 0 deletions

diff --git a/src/vpp-api/python/vpp_papi/vpp_format.py b/src/vpp-api/python/vpp_papi/vpp_format.py
new file mode 100644
index 00000000000..b1800d87dd1
--- /dev/null
+++ b/src/vpp-api/python/vpp_papi/vpp_format.py
@@ -0,0 +1,144 @@
+#
+# Copyright (c) 2018 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from socket import inet_pton, inet_ntop, AF_INET6, AF_INET
+
+
+class VPPFormat:
+    @staticmethod
+    def format_vl_api_ip6_prefix_t(args):
+        prefix, len = args.split('/')
+        return {'prefix': {'address': inet_pton(AF_INET6, prefix)},
+                'len': int(len)}
+
+    @staticmethod
+    def unformat_vl_api_ip6_prefix_t(args):
+        return "{}/{}".format(inet_ntop(AF_INET6, args.prefix.address),
+                              args.len)
+
+    @staticmethod
+    def format_vl_api_ip4_prefix_t(args):
+        prefix, len = args.split('/')
+        return {'prefix': {'address': inet_pton(AF_INET, prefix)},
+                'len': int(len)}
+
+    @staticmethod
+    def unformat_vl_api_ip4_prefix_t(args):
+        return "{}/{}".format(inet_ntop(AF_INET, args.prefix.address),
+                              args.len)
+
+    @staticmethod
+    def format_vl_api_ip6_address_t(args):
+        return {'address': inet_pton(AF_INET6, args)}
+
+    @staticmethod
+    def format_vl_api_ip4_address_t(args):
+        return {'address': inet_pton(AF_INET, args)}
+
+    @staticmethod
+    def format_vl_api_address_t(args):
+        try:
+            return {'un': {'ip6': {'address': inet_pton(AF_INET6, args)}},
+                    'af': int(1)}
+        except Exception as e:
+            return {'un': {'ip4': {'address': inet_pton(AF_INET, args)}},
+                    'af': int(0)}
+
+    @staticmethod
+    def unformat_vl_api_address_t(arg):
+        if arg.af == 1:
+            return inet_ntop(AF_INET6, arg.un.ip6.address)
+        if arg.af == 0:
+            return inet_ntop(AF_INET, arg.un.ip4.address)
+        raise
+
+    @staticmethod
+    def format_vl_api_prefix_t(args):
+        prefix, len = args.split('/')
+        return {'address': VPPFormat.format_vl_api_address_t(prefix),
+                'address_length': int(len)}
+
+    @staticmethod
+    def unformat_vl_api_prefix_t(arg):
+        if arg.address.af == 1:
+            return "{}/{}".format(inet_ntop(AF_INET6,
+                                            arg.address.un.ip6.address),
+                                  arg.address_length)
+        if arg.address.af == 0:
+            return "{}/{}".format(inet_ntop(AF_INET,
+                                            arg.address.un.ip4.address),
+                                  arg.address_length)
+        raise
+
+    @staticmethod
+    def format_u8(args):
+        try:
+            return int(args)
+        except Exception as e:
+            return args.encode()
+
+    @staticmethod
+    def format(typename, args):
+        try:
+            return getattr(VPPFormat, 'format_' + typename)(args)
+        except AttributeError:
+            # Default
+            return (int(args))
+
+    @staticmethod
+    def unformat_bytes(args):
+        try:
+            return args.decode('utf-8')
+        except Exception as e:
+            return args
+
+    @staticmethod
+    def unformat_list(args):
+        s = '['
+        for f in args:
+            t = type(f).__name__
+            if type(f) is int:
+                s2 = str(f)
+            else:
+                s2 = VPPFormat.unformat_t(t, f)
+            s += '{} '.format(s2)
+        return s[:-1] + ']'
+
+    @staticmethod
+    def unformat(args):
+        s = ''
+        return VPPFormat.unformat_t(type(args).__name__, args)
+        '''
+        for i, f in enumerate(args):
+            print('F', f)
+            t = type(f).__name__
+            if type(f) is int:
+                s2 = str(f)
+            else:
+                s2 = VPPFormat.unformat_t(t, f)
+            s += '{} {} '.format(args._fields[i], s2)
+        return s[:-1]
+        '''
+
+    @staticmethod
+    def unformat_t(typename, args):
+        try:
+            return getattr(VPPFormat, 'unformat_' + typename)(args)
+        except AttributeError:
+            # Type without explicit override
+            return VPPFormat.unformat(args)
+
+        # Default handling
+        return args