Source/WebKit/GPUProcess/media/RemoteAudioSessionProxyManager.cpp

/*
 * Copyright (C) 2020 Apple Inc. All rights reserved.
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#include "config.h"
#include "RemoteAudioSessionProxyManager.h"

#if ENABLE(GPU_PROCESS) && USE(AUDIO_SESSION)

#include "GPUProcess.h"
#include "GPUProcessConnectionMessages.h"
#include "RemoteAudioSessionProxy.h"
#include <WebCore/AudioSession.h>
#include <wtf/HashCountedSet.h>

namespace WebKit {

using namespace WebCore;

static bool categoryCanMixWithOthers(AudioSession::CategoryType category)
{
    return category == AudioSession::CategoryType::AmbientSound;
}

RemoteAudioSessionProxyManager::RemoteAudioSessionProxyManager()
{
    AudioSession::sharedSession().addInterruptionObserver(*this);
    AudioSession::sharedSession().addConfigurationChangeObserver(*this);
}

RemoteAudioSessionProxyManager::~RemoteAudioSessionProxyManager()
{
    AudioSession::sharedSession().removeInterruptionObserver(*this);
    AudioSession::sharedSession().removeConfigurationChangeObserver(*this);
}

void RemoteAudioSessionProxyManager::addProxy(RemoteAudioSessionProxy& proxy, std::optional<audit_token_t> auditToken)
{
    ASSERT(!m_proxies.contains(proxy));
    m_proxies.add(proxy);
    updateCategory();

    if (auditToken)
        AudioSession::sharedSession().setHostProcessAttribution(*auditToken);
}

void RemoteAudioSessionProxyManager::removeProxy(RemoteAudioSessionProxy& proxy)
{
    ASSERT(m_proxies.contains(proxy));
    m_proxies.remove(proxy);
    updateCategory();
}

void RemoteAudioSessionProxyManager::updateCategory()
{
    AudioSession::CategoryType category = AudioSession::CategoryType::None;
    RouteSharingPolicy policy = RouteSharingPolicy::Default;

    HashCountedSet<AudioSession::CategoryType, WTF::IntHash<AudioSession::CategoryType>, WTF::StrongEnumHashTraits<AudioSession::CategoryType>> categoryCounts;
    HashCountedSet<RouteSharingPolicy, WTF::IntHash<RouteSharingPolicy>, WTF::StrongEnumHashTraits<RouteSharingPolicy>> policyCounts;
    for (auto& otherProxy : m_proxies) {
        categoryCounts.add(otherProxy.category());
        policyCounts.add(otherProxy.routeSharingPolicy());
    }

    if (categoryCounts.contains(AudioSession::CategoryType::PlayAndRecord))
        category = AudioSession::CategoryType::PlayAndRecord;
    else if (categoryCounts.contains(AudioSession::CategoryType::RecordAudio))
        category = AudioSession::CategoryType::RecordAudio;
    else if (categoryCounts.contains(AudioSession::CategoryType::MediaPlayback))
        category = AudioSession::CategoryType::MediaPlayback;
    else if (categoryCounts.contains(AudioSession::CategoryType::SoloAmbientSound))
        category = AudioSession::CategoryType::SoloAmbientSound;
    else if (categoryCounts.contains(AudioSession::CategoryType::AmbientSound))
        category = AudioSession::CategoryType::AmbientSound;
    else if (categoryCounts.contains(AudioSession::CategoryType::AudioProcessing))
        category = AudioSession::CategoryType::AudioProcessing;
    else
        category = AudioSession::CategoryType::None;

    policy = RouteSharingPolicy::Default;
    if (policyCounts.contains(RouteSharingPolicy::LongFormVideo))
        policy = RouteSharingPolicy::LongFormVideo;
    else if (policyCounts.contains(RouteSharingPolicy::LongFormAudio))
        policy = RouteSharingPolicy::LongFormAudio;
    else if (policyCounts.contains(RouteSharingPolicy::Independent))
        ASSERT_NOT_REACHED();

    AudioSession::sharedSession().setCategory(category, policy);
}

void RemoteAudioSessionProxyManager::setPreferredBufferSizeForProcess(RemoteAudioSessionProxy& proxy, size_t preferredBufferSize)
{
    for (auto& otherProxy : m_proxies) {
        if (otherProxy.preferredBufferSize() && otherProxy.preferredBufferSize() < preferredBufferSize)
            preferredBufferSize = otherProxy.preferredBufferSize();
    }

    AudioSession::sharedSession().setPreferredBufferSize(preferredBufferSize);
}

bool RemoteAudioSessionProxyManager::tryToSetActiveForProcess(RemoteAudioSessionProxy& proxy, bool active)
{
    ASSERT(m_proxies.contains(proxy));

    size_t activeProxyCount { 0 };
    for (auto& otherProxy : m_proxies) {
        if (otherProxy.isActive())
            ++activeProxyCount;
    }

    if (!active && activeProxyCount > 1) {
        // This proxy wants to de-activate, but other proxies are still
        // active. No-op, and return deactivation was sucessful.
        return true;
    }

    if (!active) {
        // This proxy wants to de-activate, and is the last remaining active
        // proxy. Deactivate the session, and return whether that deactivation
        // was sucessful;
        return AudioSession::sharedSession().tryToSetActive(false);
    }

    if (active && !activeProxyCount) {
        // This proxy and only this proxy wants to become active. Activate
        // the session, and return whether that activation was successful.
        return AudioSession::sharedSession().tryToSetActive(active);
    }

    // If this proxy is Ambient, and the session is already active, this
    // proxy will mix with the active proxies. No-op, and return activation
    // was sucessful.
    if (categoryCanMixWithOthers(proxy.category()))
        return true;

#if PLATFORM(IOS_FAMILY)
    // Otherwise, this proxy wants to become active, but there are other
    // proxies who are already active. Walk over the proxies, and interrupt
    // those proxies whose categories indicate they cannot mix with others.
    for (auto& otherProxy : m_proxies) {
        if (otherProxy.processIdentifier() == proxy.processIdentifier())
            continue;

        if (!otherProxy.isActive())
            continue;

        if (categoryCanMixWithOthers(otherProxy.category()))
            continue;

        otherProxy.beginInterruption();
    }
#endif
    return true;
}

void RemoteAudioSessionProxyManager::beginAudioSessionInterruption()
{
    m_proxies.forEach([](auto& proxy) {
        if (proxy.isActive())
            proxy.beginInterruption();
    });
}

void RemoteAudioSessionProxyManager::endAudioSessionInterruption(AudioSession::MayResume mayResume)
{
    m_proxies.forEach([mayResume](auto& proxy) {
        if (proxy.isActive())
            proxy.endInterruption(mayResume);
    });
}

void RemoteAudioSessionProxyManager::hardwareMutedStateDidChange(const AudioSession& session)
{
    configurationDidChange(session);
}

void RemoteAudioSessionProxyManager::bufferSizeDidChange(const AudioSession& session)
{
    configurationDidChange(session);
}

void RemoteAudioSessionProxyManager::sampleRateDidChange(const AudioSession& session)
{
    configurationDidChange(session);
}

void RemoteAudioSessionProxyManager::configurationDidChange(const WebCore::AudioSession&)
{
    m_proxies.forEach([](auto& proxy) {
        proxy.configurationChanged();
    });
}

}

#endif