[RFC PATCH v1 20/23] dts: merge DTS framework/flow/flow_items.py to DPDK

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

---
 dts/framework/flow/flow_items.py | 128 +++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 dts/framework/flow/flow_items.py

diff --git a/dts/framework/flow/flow_items.py b/dts/framework/flow/flow_items.py
new file mode 100644
index 0000000000..e43614c587
--- /dev/null
+++ b/dts/framework/flow/flow_items.py
@@ -0,0 +1,128 @@
+# BSD LICENSE
+#
+# Copyright(c) 2020 Intel Corporation. All rights reserved.
+# Copyright © 2018[, 2019] The University of New Hampshire. All rights reserved.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#   * Neither the name of Intel Corporation nor the names of its
+#     contributors may be used to endorse or promote products derived
+#     from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import annotations
+
+import copy
+import itertools
+from functools import reduce
+from typing import Any, Dict, FrozenSet, Hashable, Iterable, Set, Tuple, Union
+
+from .enums import FlowActionType, FlowItemType
+from .exceptions import InvalidFlowItemException
+
+PATTERN_ACTION_ITEMS = {
+    FlowItemType.INVERT,
+    FlowItemType.VOID,
+    FlowItemType.MARK,
+    FlowItemType.META,
+}
+
+
+class FlowItem(object):
+    type: Union[FlowItemType, FlowActionType]
+    # Defines what items this may not appear with
+    allowed_with: FrozenSet[Union[FlowItemType, FlowActionType]]
+    # OSI Model layer of the protocol
+    # This should be the lowest layer a protocol is used in, for example
+    # QUIC would be considered L5 since it needs to go after UDP (L4),
+    # even though it has capabilities in L6.
+    layer: int
+    valid_next_items: FrozenSet[Union[FlowItemType, FlowActionType]]
+
+    # Types subject to change, should only be accessed through
+    possible_properties: Dict[str, Tuple[str, FrozenSet[str], FrozenSet[str]]]
+    properties: str
+
+    def get_property_stream(
+        self,
+    ) -> Iterable[Tuple[FlowItem, FrozenSet[str], FrozenSet[str], str]]:
+        """
+        This function will return a generator that will provide all
+        configured property combinations.
+
+        This function will not mutate the instance it is called on.
+
+        @return: a generator that will provide all
+        permutations of possible properties this object has as a flow
+        item with properties
+        """
+        base_copy = copy.deepcopy(self)
+        for key, value in self.possible_properties.items():
+            new_copy = copy.deepcopy(base_copy)
+            new_copy.properties = value[0]  # The properties string
+            yield new_copy, *value[1:], f"{self.type.value}_{key}"
+
+    def __init__(self):
+        self.properties = ""
+
+    def __truediv__(self, other: FlowItem):
+        """
+        Used in a similar way to scapy's packet composition.
+        @param other: The other flow item.
+        @return: A Flow containing both items
+        """
+        if type(self) != type(other):
+            raise InvalidFlowItemException(self, other)
+        elif other.type in self.valid_next_items:
+            # These imports are in here so there is no circular import
+            from framework.flow.flow_action_items import ActionFlowItem
+            from framework.flow.flow_pattern_items import PatternFlowItem
+
+            from .flow import Flow
+
+            if isinstance(self, PatternFlowItem):
+                return Flow(pattern_items=[self, other])
+            elif isinstance(self, ActionFlowItem):
+                return Flow(action_items=[self, other])
+            else:
+                raise TypeError(
+                    f"{type(self):s} is not one of {PatternFlowItem:s}, {ActionFlowItem:s}."
+                )
+        else:
+            raise InvalidFlowItemException(self, other)
+
+    def __eq__(self, other) -> bool:
+        return (
+            type(self) == type(other)
+            and self.type == other.type
+            and self.properties == other.properties
+        )
+
+    def __str__(self):
+        if self.properties != "":
+            return self.properties
+        else:
+            return self.type.value
+
+    def __repr__(self):
+        return str(self)
-- 
2.20.1