python: reimplement the babeltrace package as a bt2 wrapper

[babeltrace.git] / bindings / python / babeltrace / babeltrace / reader_event_declaration.py

diff --git a/bindings/python/babeltrace/babeltrace/reader_event_declaration.py b/bindings/python/babeltrace/babeltrace/reader_event_declaration.py
new file mode 100644 (file)
index 0000000..7959bf6
--- /dev/null
+++ b/bindings/python/babeltrace/babeltrace/reader_event_declaration.py
@@ -0,0 +1,149 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2013-2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+import bt2
+import babeltrace.common as common
+import babeltrace.reader_field_declaration as field_declaration
+import collections
+
+def _create_event_declaration(event_class):
+    event_declaration = EventDeclaration.__new__(EventDeclaration)
+    event_declaration._event_class = event_class
+    return event_declaration
+
+class EventDeclaration:
+    """
+    An event declaration contains the properties of a class of events,
+    that is, the common properties and fields layout of all the actual
+    recorded events associated with this declaration.
+
+    This class is not meant to be instantiated by the user. It is
+    returned by :attr:`TraceHandle.events`.
+    """
+    def __init__(self):
+        raise NotImplementedError("EventDeclaration cannot be instantiated")
+
+    def _get_scope_field_type(self, scope):
+        try:
+            ec = self._event_class
+            if scope is common.CTFScope.EVENT_FIELDS:
+                return ec.payload_field_type
+
+            if scope is common.CTFScope.EVENT_CONTEXT:
+                return ec.context_field_type
+
+            if scope is common.CTFScope.STREAM_EVENT_CONTEXT:
+                return ec.stream_class.event_context_field_type
+
+            if scope is common.CTFScope.STREAM_EVENT_HEADER:
+                return ec.stream_class.event_header_field_type
+
+            if scope is common.CTFScope.STREAM_PACKET_CONTEXT:
+                return ec.stream_class.packet_context_field_type
+
+            if scope is common.CTFScope.TRACE_PACKET_HEADER:
+                return ec.stream_class.trace.packet_header_field_type
+        except bt2.Error:
+            return
+
+        raise ValueError("Invalid scope provided")
+
+    @property
+    def name(self):
+        """
+        Event name, or ``None`` on error.
+        """
+
+        return self._event_class.name
+
+    @property
+    def id(self):
+        """
+        Event numeric ID, or -1 on error.
+        """
+
+        return self._event_class.id
+
+    @property
+    def fields(self):
+        """
+        Generates all the field declarations of this event, going
+        through each scope in the following order:
+
+        1. Event fields (:attr:`babeltrace.common.CTFScope.EVENT_FIELDS`)
+        2. Event context (:attr:`babeltrace.common.CTFScope.EVENT_CONTEXT`)
+        3. Stream event context (:attr:`babeltrace.common.CTFScope.STREAM_EVENT_CONTEXT`)
+        4. Event header (:attr:`babeltrace.common.CTFScope.STREAM_EVENT_HEADER`)
+        5. Packet context (:attr:`babeltrace.common.CTFScope.STREAM_PACKET_CONTEXT`)
+        6. Packet header (:attr:`babeltrace.common.CTFScope.TRACE_PACKET_HEADER`)
+
+        All the generated field declarations inherit
+        :class:`FieldDeclaration`, and are among:
+
+        * :class:`IntegerFieldDeclaration`
+        * :class:`FloatFieldDeclaration`
+        * :class:`EnumerationFieldDeclaration`
+        * :class:`StringFieldDeclaration`
+        * :class:`ArrayFieldDeclaration`
+        * :class:`SequenceFieldDeclaration`
+        * :class:`StructureFieldDeclaration`
+        * :class:`VariantFieldDeclaration`
+        """
+
+        for scope in _SCOPES:
+            for declaration in self.fields_scope(scope):
+                yield declaration
+
+    def fields_scope(self, scope):
+        """
+        Generates all the field declarations of the event's scope
+        *scope*.
+
+        *scope* must be one of :class:`babeltrace.common.CTFScope` constants.
+
+        All the generated field declarations inherit
+        :class:`FieldDeclaration`, and are among:
+
+        * :class:`IntegerFieldDeclaration`
+        * :class:`FloatFieldDeclaration`
+        * :class:`EnumerationFieldDeclaration`
+        * :class:`StringFieldDeclaration`
+        * :class:`ArrayFieldDeclaration`
+        * :class:`SequenceFieldDeclaration`
+        * :class:`StructureFieldDeclaration`
+        * :class:`VariantFieldDeclaration`
+        """
+
+        scope_field_type = self._get_scope_field_type(scope)
+        for name, field_type in scope_field_type.items():
+            yield field_declaration._create_field_declaration(field_type, name,
+                                                              scope)
+
+# Priority of the scopes when searching for event fields
+_SCOPES = [
+    common.CTFScope.EVENT_FIELDS,
+    common.CTFScope.EVENT_CONTEXT,
+    common.CTFScope.STREAM_EVENT_CONTEXT,
+    common.CTFScope.STREAM_EVENT_HEADER,
+    common.CTFScope.STREAM_PACKET_CONTEXT,
+    common.CTFScope.TRACE_PACKET_HEADER
+]