/* * Copyright (C) 2019 The Android Open Source Project * * 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. */ #ifndef INCLUDE_PERFETTO_TRACING_EVENT_CONTEXT_H_ #define INCLUDE_PERFETTO_TRACING_EVENT_CONTEXT_H_ #include "perfetto/protozero/message_handle.h" #include "perfetto/tracing/internal/track_event_internal.h" #include "perfetto/tracing/traced_proto.h" #include "protos/perfetto/trace/trace_packet.pbzero.h" namespace perfetto { namespace internal { class TrackEventInternal; } // Allows adding custom arguments into track events. Example: // // TRACE_EVENT_BEGIN("category", "Title", // [](perfetto::EventContext ctx) { // auto* dbg = ctx.event()->add_debug_annotations(); // dbg->set_name("name"); // dbg->set_int_value(1234); // }); // class PERFETTO_EXPORT EventContext { public: EventContext(EventContext&&) = default; // For Chromium during the transition phase to the client library. // TODO(eseckler): Remove once Chromium has switched to client lib entirely. explicit EventContext( protos::pbzero::TrackEvent* event, internal::TrackEventIncrementalState* incremental_state = nullptr) : event_(event), incremental_state_(incremental_state) {} ~EventContext(); // Get a TrackEvent message to write typed arguments to. // // event() is a template method to allow callers to specify a subclass of // TrackEvent instead. Those subclasses correspond to TrackEvent message with // application-specific extensions. More information in // design-docs/extensions.md. template EventType* event() const { // As the method does downcasting, we check that a target subclass does // not add new fields. static_assert( sizeof(EventType) == sizeof(protos::pbzero::TrackEvent), "Event type must be binary-compatible with protos::pbzero::TrackEvent"); return static_cast(event_); } // Convert a raw pointer to protozero message to TracedProto which captures // the reference to this EventContext. template TracedProto Wrap(MessageType* message) { static_assert(std::is_base_of::value, "TracedProto can be used only with protozero messages"); return TracedProto(message, *this); } private: template friend class TrackEventInternedDataIndex; friend class internal::TrackEventInternal; using TracePacketHandle = ::protozero::MessageHandle; EventContext(TracePacketHandle, internal::TrackEventIncrementalState*); EventContext(const EventContext&) = delete; TracePacketHandle trace_packet_; protos::pbzero::TrackEvent* event_; internal::TrackEventIncrementalState* incremental_state_; }; } // namespace perfetto #endif // INCLUDE_PERFETTO_TRACING_EVENT_CONTEXT_H_