Source/WebCore/platform/gamepad/mac/HIDGamepad.cpp

/*
 * Copyright (C) 2014 Apple Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
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 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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#include "config.h"
#include "HIDGamepad.h"

#if ENABLE(GAMEPAD) && PLATFORM(MAC)

#include <IOKit/hid/IOHIDElement.h>
#include <IOKit/hid/IOHIDUsageTables.h>
#include <IOKit/hid/IOHIDValue.h>
#include <wtf/HexNumber.h>
#include <wtf/cf/TypeCastsCF.h>
#include <wtf/text/CString.h>

WTF_DECLARE_CF_TYPE_TRAIT(IOHIDElement);

namespace WebCore {

HIDGamepad::HIDGamepad(IOHIDDeviceRef hidDevice, unsigned index)
    : PlatformGamepad(index)
    , m_hidDevice(hidDevice)
{
    m_connectTime = m_lastUpdateTime = MonotonicTime::now();

    CFNumberRef cfVendorID = (CFNumberRef)IOHIDDeviceGetProperty(hidDevice, CFSTR(kIOHIDVendorIDKey));
    CFNumberRef cfProductID = (CFNumberRef)IOHIDDeviceGetProperty(hidDevice, CFSTR(kIOHIDProductIDKey));

    int vendorID, productID;
    CFNumberGetValue(cfVendorID, kCFNumberIntType, &vendorID);
    CFNumberGetValue(cfProductID, kCFNumberIntType, &productID);

    CFStringRef cfProductName = (CFStringRef)IOHIDDeviceGetProperty(hidDevice, CFSTR(kIOHIDProductKey));
    String productName(cfProductName);

    // Currently the spec has no formatting for the id string.
    // This string formatting matches Firefox.
    m_id = makeString(hex(vendorID, Lowercase), '-', hex(productID, Lowercase), '-', productName);

    initElements();
}

void HIDGamepad::getCurrentValueForElement(const HIDGamepadElement& gamepadElement)
{
    IOHIDElementRef element = gamepadElement.iohidElement.get();
    IOHIDValueRef value;
    if (IOHIDDeviceGetValue(IOHIDElementGetDevice(element), element, &value) == kIOReturnSuccess)
        valueChanged(value);
}

void HIDGamepad::initElements()
{
    RetainPtr<CFArrayRef> elements = adoptCF(IOHIDDeviceCopyMatchingElements(m_hidDevice.get(), NULL, kIOHIDOptionsTypeNone));
    initElementsFromArray(elements.get());

    // Buttons are specified to appear highest priority first in the array.
    std::sort(m_buttons.begin(), m_buttons.end(), [](auto& a, auto& b) {
        return a->priority < b->priority;
    });

    m_axisValues.resize(m_axes.size());
    m_buttonValues.resize(m_buttons.size() + (m_dPads.size() * 4));

    for (auto& button : m_buttons)
        getCurrentValueForElement(button.get());

    for (auto& dPad : m_dPads)
        getCurrentValueForElement(dPad.get());

    for (auto& axis : m_axes)
        getCurrentValueForElement(axis.get());
}

void HIDGamepad::initElementsFromArray(CFArrayRef elements)
{
    for (CFIndex i = 0, count = CFArrayGetCount(elements); i < count; ++i) {
        IOHIDElementRef element = checked_cf_cast<IOHIDElementRef>(CFArrayGetValueAtIndex(elements, i));
        if (CFGetTypeID(element) != IOHIDElementGetTypeID())
            continue;

        // As a physical element can appear in the device twice (in different collections) and can be
        // represented by different IOHIDElementRef objects, we look at the IOHIDElementCookie which
        // is meant to be unique for each physical element.
        IOHIDElementCookie cookie = IOHIDElementGetCookie(element);
        if (m_elementMap.contains(cookie))
            continue;

        IOHIDElementType type = IOHIDElementGetType(element);

        if ((type == kIOHIDElementTypeInput_Misc || type == kIOHIDElementTypeInput_Button)) {
            if (maybeAddButton(element))
                continue;
            if (maybeAddDPad(element))
                continue;
        }

        if ((type == kIOHIDElementTypeInput_Misc || type == kIOHIDElementTypeInput_Axis) && maybeAddAxis(element))
            continue;

        if (type == kIOHIDElementTypeCollection)
            initElementsFromArray(IOHIDElementGetChildren(element));
    }
}

bool HIDGamepad::maybeAddButton(IOHIDElementRef element)
{
    uint32_t usagePage = IOHIDElementGetUsagePage(element);
    if (usagePage != kHIDPage_Button && usagePage != kHIDPage_GenericDesktop)
        return false;

    uint32_t usage = IOHIDElementGetUsage(element);

    if (usagePage == kHIDPage_GenericDesktop) {
        if (usage < kHIDUsage_GD_DPadUp || usage > kHIDUsage_GD_DPadLeft)
            return false;
        usage = std::numeric_limits<uint32_t>::max();
    } else if (!usage)
        return false;

    CFIndex min = IOHIDElementGetLogicalMin(element);
    CFIndex max = IOHIDElementGetLogicalMax(element);

    m_buttons.append(makeUniqueRef<HIDGamepadButton>(usage, min, max, element));

    IOHIDElementCookie cookie = IOHIDElementGetCookie(element);
    m_elementMap.set(cookie, &m_buttons.last().get());

    return true;
}

bool HIDGamepad::maybeAddDPad(IOHIDElementRef element)
{
    uint32_t usagePage = IOHIDElementGetUsagePage(element);
    if (usagePage != kHIDPage_GenericDesktop)
        return false;

    uint32_t usage = IOHIDElementGetUsage(element);
    if (!usage || usage != kHIDUsage_GD_Hatswitch)
        return false;

    CFIndex min = IOHIDElementGetLogicalMin(element);
    CFIndex max = IOHIDElementGetLogicalMax(element);

    m_dPads.append(makeUniqueRef<HIDGamepadDPad>(min, max, element));

    IOHIDElementCookie cookie = IOHIDElementGetCookie(element);
    m_elementMap.set(cookie, &m_dPads.last().get());

    return true;
}

bool HIDGamepad::maybeAddAxis(IOHIDElementRef element)
{
    uint32_t usagePage = IOHIDElementGetUsagePage(element);
    if (usagePage != kHIDPage_GenericDesktop)
        return false;

    uint32_t usage = IOHIDElementGetUsage(element);
    // This range covers the standard axis usages.
    if (usage < kHIDUsage_GD_X || usage > kHIDUsage_GD_Rz)
        return false;

    CFIndex min = IOHIDElementGetPhysicalMin(element);
    CFIndex max = IOHIDElementGetPhysicalMax(element);

    m_axes.append(makeUniqueRef<HIDGamepadAxis>(min, max, element));

    IOHIDElementCookie cookie = IOHIDElementGetCookie(element);
    m_elementMap.set(cookie, &m_axes.last().get());

    return true;
}

static void fillInButtonValues(int value, double& button0, double& button1, double& button2, double& button3)
{
    // Standard DPads have 8 possible position values, moving around a circle:
    // 0 - Up
    // 1 - Up + right
    // 2 - Right
    // 3 - Down + right
    // 4 - Down
    // 5 - Down + left
    // 6 - Left
    // 7 - Up and Left
    // These 8 positions are mapped on to 4 button positions:
    // 0 - Up
    // 1 - Down
    // 2 - Left
    // 3 - Right

    if (value < 0 || value > 7) {
        // Handle an invalid input value that we don't know how to interpret.
        button0 = 0.0;
        button1 = 0.0;
        button2 = 0.0;
        button3 = 0.0;
        return;
    }

    button0 = value < 2 || value == 7 ? 1.0 : 0.0;
    button1 = value > 2 && value < 6 ? 1.0 : 0.0;
    button2 = value > 4 ? 1.0 : 0.0;
    button3 = value > 0 && value < 4 ? 1.0 : 0.0;
}

HIDInputType HIDGamepad::valueChanged(IOHIDValueRef value)
{
    IOHIDElementCookie cookie = IOHIDElementGetCookie(IOHIDValueGetElement(value));
    HIDGamepadElement* element = m_elementMap.get(cookie);

    // This might be an element we don't currently handle as input so we can skip it.
    if (!element)
        return HIDInputType::NotAButtonPress;

    element->rawValue = IOHIDValueGetScaledValue(value, kIOHIDValueScaleTypePhysical);

    if (element->isButton()) {
        for (unsigned i = 0; i < m_buttons.size(); ++i) {
            if (&m_buttons[i].get() == element) {
                m_buttonValues[i] = element->normalizedValue();
                break;
            }
        }
    } else if (element->isAxis()) {
        for (unsigned i = 0; i < m_axes.size(); ++i) {
            if (&m_axes[i].get() == element) {
                m_axisValues[i] = element->normalizedValue();
                break;
            }
        }
    } else if (element->isDPad()) {
        int intValue = IOHIDValueGetIntegerValue(value) - element->min;
        for (unsigned i = 0; i < m_dPads.size(); ++i) {
            if (&m_dPads[i].get() != element)
                continue;

            // Each DPad represents 4 button values which are tacked on to the end of the values from non-DPad buttons.
            unsigned firstButtonValue = m_buttons.size() + i * 4;

            ASSERT(m_buttonValues.size() > firstButtonValue + 3);

            fillInButtonValues(intValue, m_buttonValues[firstButtonValue], m_buttonValues[firstButtonValue + 1], m_buttonValues[firstButtonValue + 2], m_buttonValues[firstButtonValue + 3]);
        }
    } else
        ASSERT_NOT_REACHED();

    m_lastUpdateTime = MonotonicTime::now();

    return element->isButton() ? HIDInputType::ButtonPress : HIDInputType::NotAButtonPress;
}

} // namespace WebCore

#endif // ENABLE(GAMEPAD) && PLATFORM(MAC)