123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104 |
- // Copyright 2014 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef CC_SCHEDULER_BEGIN_FRAME_TRACKER_H_
- #define CC_SCHEDULER_BEGIN_FRAME_TRACKER_H_
- #include <set>
- #include <string>
- #include "base/time/time.h"
- #include "cc/cc_export.h"
- #include "components/viz/common/frame_sinks/begin_frame_args.h"
- namespace perfetto {
- class EventContext;
- namespace protos {
- namespace pbzero {
- class BeginImplFrameArgs;
- }
- } // namespace protos
- } // namespace perfetto
- namespace cc {
- // Microclass to trace and check properties for correct BeginFrameArgs (BFA)
- // usage and provide a few helper methods.
- //
- // With DCHECKs enable, this class checks the following "invariants";
- // * BFA are monotonically increasing.
- // * BFA is valid.
- // * The BFA is only used inside a given period.
- // * A new BFA isn't used before the last BFA is finished with.
- //
- // With the tracing category "cc.debug.scheduler.frames" enabled the tracker
- // will output the following trace information;
- // * Time period for which the BFA is in usage.
- // * The flow of BFA as they are passed between tracking objects.
- //
- // TODO(mithro): Record stats about the viz::BeginFrameArgs
- class CC_EXPORT BeginFrameTracker {
- public:
- explicit BeginFrameTracker(const base::Location& location);
- ~BeginFrameTracker();
- // The Start and Finish methods manage the period that a BFA should be
- // accessed for. This allows tight control over the BFA and prevents
- // accidental usage in the wrong period when code is split across multiple
- // locations.
- // Start using a new BFA value and check invariant properties.
- // **Must** only be called after finishing with any previous BFA.
- void Start(const viz::BeginFrameArgs& new_args);
- // Finish using the current BFA.
- // **Must** only be called while still using a BFA.
- void Finish();
- // The two accessors methods allow access to the BFA stored inside the
- // tracker. They are mutually exclusive, at any time it is only valid to call
- // one or the other. This makes sure you understand exactly which BFA you are
- // intending to use and verifies that is the case.
- // Get the current BFA object.
- // **Must** only be called between the start and finish methods calls.
- const viz::BeginFrameArgs& Current() const;
- // Get the last used BFA.
- // **Must** only be called when **not** between the start and finish method
- // calls.
- const viz::BeginFrameArgs& Last() const;
- // Helper method to try and return a valid interval property. Defaults to
- // BFA::DefaultInterval() is no other interval can be found. Can be called at
- // any time.
- base::TimeDelta Interval() const;
- void AsProtozeroInto(
- perfetto::EventContext& ctx,
- base::TimeTicks now,
- perfetto::protos::pbzero::BeginImplFrameArgs* dict) const;
- // The following methods violate principles of how viz::BeginFrameArgs should
- // be used. These methods should only be used when there is no other choice.
- bool DangerousMethodHasStarted() const {
- return !current_updated_at_.is_null();
- }
- bool DangerousMethodHasFinished() const { return HasFinished(); }
- const viz::BeginFrameArgs& DangerousMethodCurrentOrLast() const;
- private:
- // Return if currently not between the start/end period. This method should
- // be used extremely sparingly and normal indicates incorrect management of
- // the BFA object. Can be called at any time.
- bool HasFinished() const { return !current_finished_at_.is_null(); }
- const base::Location location_;
- const std::string location_string_;
- base::TimeTicks current_updated_at_;
- viz::BeginFrameArgs current_args_;
- base::TimeTicks current_finished_at_;
- };
- } // namespace cc
- #endif // CC_SCHEDULER_BEGIN_FRAME_TRACKER_H_
|