libs/input/Keyboard.cpp

/*
 * Copyright (C) 2010 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.
 */

#define LOG_TAG "Keyboard"

#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include <optional>

#include <input/InputDevice.h>
#include <input/InputEventLabels.h>
#include <input/KeyCharacterMap.h>
#include <input/KeyLayoutMap.h>
#include <input/Keyboard.h>
#include <log/log.h>
#include <utils/Errors.h>

namespace android {

static std::string getPath(const InputDeviceIdentifier& deviceIdentifier, const std::string& name,
                           InputDeviceConfigurationFileType type) {
    return name.empty()
            ? getInputDeviceConfigurationFilePathByDeviceIdentifier(deviceIdentifier, type)
            : getInputDeviceConfigurationFilePathByName(name, type);
}

// --- KeyMap ---

KeyMap::KeyMap() {
}

KeyMap::~KeyMap() {
}

status_t KeyMap::load(const InputDeviceIdentifier& deviceIdentifier,
        const PropertyMap* deviceConfiguration) {
    // Use the configured key layout if available.
    if (deviceConfiguration) {
        std::optional<std::string> keyLayoutName =
                deviceConfiguration->getString("keyboard.layout");
        if (keyLayoutName.has_value()) {
            status_t status = loadKeyLayout(deviceIdentifier, *keyLayoutName);
            if (status == NAME_NOT_FOUND) {
                ALOGE("Configuration for keyboard device '%s' requested keyboard layout '%s' but "
                      "it was not found.",
                      deviceIdentifier.name.c_str(), keyLayoutName->c_str());
            }
        }

        std::optional<std::string> keyCharacterMapName =
                deviceConfiguration->getString("keyboard.characterMap");
        if (keyCharacterMapName.has_value()) {
            status_t status = loadKeyCharacterMap(deviceIdentifier, *keyCharacterMapName);
            if (status == NAME_NOT_FOUND) {
                ALOGE("Configuration for keyboard device '%s' requested keyboard character "
                      "map '%s' but it was not found.",
                      deviceIdentifier.name.c_str(), keyCharacterMapName->c_str());
            }
        }

        if (isComplete()) {
            return OK;
        }
    }

    // Try searching by device identifier.
    if (probeKeyMap(deviceIdentifier, "")) {
        return OK;
    }

    // Fall back on the Generic key map.
    // TODO Apply some additional heuristics here to figure out what kind of
    //      generic key map to use (US English, etc.) for typical external keyboards.
    if (probeKeyMap(deviceIdentifier, "Generic")) {
        return OK;
    }

    // Try the Virtual key map as a last resort.
    if (probeKeyMap(deviceIdentifier, "Virtual")) {
        return OK;
    }

    // Give up!
    ALOGE("Could not determine key map for device '%s' and no default key maps were found!",
            deviceIdentifier.name.c_str());
    return NAME_NOT_FOUND;
}

bool KeyMap::probeKeyMap(const InputDeviceIdentifier& deviceIdentifier,
        const std::string& keyMapName) {
    if (!haveKeyLayout()) {
        loadKeyLayout(deviceIdentifier, keyMapName);
    }
    if (!haveKeyCharacterMap()) {
        loadKeyCharacterMap(deviceIdentifier, keyMapName);
    }
    return isComplete();
}

status_t KeyMap::loadKeyLayout(const InputDeviceIdentifier& deviceIdentifier,
        const std::string& name) {
    std::string path(getPath(deviceIdentifier, name, InputDeviceConfigurationFileType::KEY_LAYOUT));
    if (path.empty()) {
        return NAME_NOT_FOUND;
    }

    base::Result<std::shared_ptr<KeyLayoutMap>> ret = KeyLayoutMap::load(path);
    if (ret.ok()) {
        keyLayoutMap = *ret;
        keyLayoutFile = path;
        return OK;
    }

    // Try to load fallback layout if the regular layout could not be loaded due to missing
    // kernel modules
    std::string fallbackPath(
            getInputDeviceConfigurationFilePathByDeviceIdentifier(deviceIdentifier,
                                                                  InputDeviceConfigurationFileType::
                                                                          KEY_LAYOUT,
                                                                  "_fallback"));
    ret = KeyLayoutMap::load(fallbackPath);
    if (!ret.ok()) {
        return ret.error().code();
    }
    keyLayoutMap = *ret;
    keyLayoutFile = fallbackPath;
    return OK;
}

status_t KeyMap::loadKeyCharacterMap(const InputDeviceIdentifier& deviceIdentifier,
        const std::string& name) {
    std::string path =
            getPath(deviceIdentifier, name, InputDeviceConfigurationFileType::KEY_CHARACTER_MAP);
    if (path.empty()) {
        return NAME_NOT_FOUND;
    }

    base::Result<std::shared_ptr<KeyCharacterMap>> ret =
            KeyCharacterMap::load(path, KeyCharacterMap::Format::BASE);
    if (!ret.ok()) {
        return ret.error().code();
    }
    keyCharacterMap = *ret;
    keyCharacterMapFile = path;
    return OK;
}

// --- Global functions ---

bool isKeyboardSpecialFunction(const PropertyMap* config) {
    if (config == nullptr) {
        return false;
    }
    return config->getBool("keyboard.specialFunction").value_or(false);
}

bool isEligibleBuiltInKeyboard(const InputDeviceIdentifier& deviceIdentifier,
        const PropertyMap* deviceConfiguration, const KeyMap* keyMap) {
    // TODO: remove the third OR statement (SPECIAL_FUNCTION) in Q
    if (!keyMap->haveKeyCharacterMap() || isKeyboardSpecialFunction(deviceConfiguration) ||
        keyMap->keyCharacterMap->getKeyboardType() ==
                KeyCharacterMap::KeyboardType::SPECIAL_FUNCTION) {
        return false;
    }

    if (deviceConfiguration) {
        if (deviceConfiguration->getBool("keyboard.builtIn").value_or(false)) {
            return true;
        }
    }

    return strstr(deviceIdentifier.name.c_str(), "-keypad");
}

static int32_t setEphemeralMetaState(int32_t mask, bool down, int32_t oldMetaState) {
    int32_t newMetaState;
    if (down) {
        newMetaState = oldMetaState | mask;
    } else {
        newMetaState = oldMetaState &
                ~(mask | AMETA_ALT_ON | AMETA_SHIFT_ON | AMETA_CTRL_ON | AMETA_META_ON);
    }

    return normalizeMetaState(newMetaState);
}

int32_t normalizeMetaState(int32_t oldMetaState) {
    int32_t newMetaState = oldMetaState;
    if (newMetaState & (AMETA_ALT_LEFT_ON | AMETA_ALT_RIGHT_ON)) {
        newMetaState |= AMETA_ALT_ON;
    }

    if (newMetaState & (AMETA_SHIFT_LEFT_ON | AMETA_SHIFT_RIGHT_ON)) {
        newMetaState |= AMETA_SHIFT_ON;
    }

    if (newMetaState & (AMETA_CTRL_LEFT_ON | AMETA_CTRL_RIGHT_ON)) {
        newMetaState |= AMETA_CTRL_ON;
    }

    if (newMetaState & (AMETA_META_LEFT_ON | AMETA_META_RIGHT_ON)) {
        newMetaState |= AMETA_META_ON;
    }
    return newMetaState;
}

static int32_t toggleLockedMetaState(int32_t mask, bool down, int32_t oldMetaState) {
    if (down) {
        return oldMetaState;
    } else {
        return oldMetaState ^ mask;
    }
}

int32_t updateMetaState(int32_t keyCode, bool down, int32_t oldMetaState) {
    switch (keyCode) {
    case AKEYCODE_ALT_LEFT:
        return setEphemeralMetaState(AMETA_ALT_LEFT_ON, down, oldMetaState);
    case AKEYCODE_ALT_RIGHT:
        return setEphemeralMetaState(AMETA_ALT_RIGHT_ON, down, oldMetaState);
    case AKEYCODE_SHIFT_LEFT:
        return setEphemeralMetaState(AMETA_SHIFT_LEFT_ON, down, oldMetaState);
    case AKEYCODE_SHIFT_RIGHT:
        return setEphemeralMetaState(AMETA_SHIFT_RIGHT_ON, down, oldMetaState);
    case AKEYCODE_SYM:
        return setEphemeralMetaState(AMETA_SYM_ON, down, oldMetaState);
    case AKEYCODE_FUNCTION:
        return setEphemeralMetaState(AMETA_FUNCTION_ON, down, oldMetaState);
    case AKEYCODE_CTRL_LEFT:
        return setEphemeralMetaState(AMETA_CTRL_LEFT_ON, down, oldMetaState);
    case AKEYCODE_CTRL_RIGHT:
        return setEphemeralMetaState(AMETA_CTRL_RIGHT_ON, down, oldMetaState);
    case AKEYCODE_META_LEFT:
        return setEphemeralMetaState(AMETA_META_LEFT_ON, down, oldMetaState);
    case AKEYCODE_META_RIGHT:
        return setEphemeralMetaState(AMETA_META_RIGHT_ON, down, oldMetaState);
    case AKEYCODE_CAPS_LOCK:
        return toggleLockedMetaState(AMETA_CAPS_LOCK_ON, down, oldMetaState);
    case AKEYCODE_NUM_LOCK:
        return toggleLockedMetaState(AMETA_NUM_LOCK_ON, down, oldMetaState);
    case AKEYCODE_SCROLL_LOCK:
        return toggleLockedMetaState(AMETA_SCROLL_LOCK_ON, down, oldMetaState);
    default:
        return oldMetaState;
    }
}

bool isMetaKey(int32_t keyCode) {
    switch (keyCode) {
    case AKEYCODE_ALT_LEFT:
    case AKEYCODE_ALT_RIGHT:
    case AKEYCODE_SHIFT_LEFT:
    case AKEYCODE_SHIFT_RIGHT:
    case AKEYCODE_SYM:
    case AKEYCODE_FUNCTION:
    case AKEYCODE_CTRL_LEFT:
    case AKEYCODE_CTRL_RIGHT:
    case AKEYCODE_META_LEFT:
    case AKEYCODE_META_RIGHT:
    case AKEYCODE_CAPS_LOCK:
    case AKEYCODE_NUM_LOCK:
    case AKEYCODE_SCROLL_LOCK:
        return true;
    default:
        return false;
    }
}


} // namespace android