Observer.cpp

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Author : Luc Ferron
Date : 2018-03-01 11:45:20
Hash : 879f90d2
Message : Vulkan: Avoid recopying the data every time we draw line loops Use the Observer pattern to get notified when the BufferVk we've copied our data from is changing. We will only recopy the data if anything has changed, but otherwise we'll keep drawing with the same index buffer we've created previously. Bug: angleproject:2335 Change-Id: Ib65677b4d5ec90c46a5e3b975fffd1fddeed59e7 Reviewed-on: https://chromium-review.googlesource.com/948622 Commit-Queue: Luc Ferron <lucferron@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>

src/libANGLE/Observer.cpp

//
// Copyright 2018 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// Observer:
//   Implements the Observer pattern for sending state change notifications
//   from Subject objects to dependent Observer objects.
//
//   See design document:
//   https://docs.google.com/document/d/15Edfotqg6_l1skTEL8ADQudF_oIdNa7i8Po43k6jMd4/

#include "libANGLE/Observer.h"

#include <algorithm>

#include "common/debug.h"

namespace angle
{
// Observer implementation.
ObserverInterface::~ObserverInterface() = default;

// Subject implementation.
Subject::Subject()
{
}

Subject::~Subject()
{
    resetObservers();
}

bool Subject::hasObservers() const
{
    return !mObservers.empty();
}

void Subject::addObserver(ObserverBinding *observer)
{
    ASSERT(std::find(mObservers.begin(), mObservers.end(), observer) == mObservers.end());
    mObservers.push_back(observer);
}

void Subject::removeObserver(ObserverBinding *observer)
{
    auto iter = std::find(mObservers.begin(), mObservers.end(), observer);
    ASSERT(iter != mObservers.end());
    mObservers.erase(iter);
}

void Subject::onStateChange(const gl::Context *context, SubjectMessage message) const
{
    if (mObservers.empty())
        return;

    for (const angle::ObserverBinding *receiver : mObservers)
    {
        receiver->onStateChange(context, message);
    }
}

void Subject::resetObservers()
{
    for (angle::ObserverBinding *observer : mObservers)
    {
        observer->onSubjectReset();
    }
    mObservers.clear();
}

// ObserverBinding implementation.
ObserverBinding::ObserverBinding(ObserverInterface *observer, SubjectIndex index)
    : mSubject(nullptr), mObserver(observer), mIndex(index)
{
    ASSERT(observer);
}

ObserverBinding::~ObserverBinding()
{
    reset();
}

ObserverBinding::ObserverBinding(const ObserverBinding &other) = default;

ObserverBinding &ObserverBinding::operator=(const ObserverBinding &other) = default;

void ObserverBinding::bind(Subject *subject)
{
    ASSERT(mObserver);
    if (mSubject)
    {
        mSubject->removeObserver(this);
    }

    mSubject = subject;

    if (mSubject)
    {
        mSubject->addObserver(this);
    }
}

void ObserverBinding::reset()
{
    bind(nullptr);
}

void ObserverBinding::onStateChange(const gl::Context *context, SubjectMessage message) const
{
    mObserver->onSubjectStateChange(context, mIndex, message);
}

void ObserverBinding::onSubjectReset()
{
    mSubject = nullptr;
}

const Subject *ObserverBinding::getSubject() const
{
    return mSubject;
}
}  // namespace angle

kc3-lang/angle/src/libANGLE/Observer.cpp

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kc3-lang/angle /src/libANGLE/Observer.cpp