/*
 * Copyright (C) 2017 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.
 */

#include "VintfObject.h"

#include <dirent.h>

#include <algorithm>
#include <functional>
#include <memory>
#include <mutex>

#include <aidl/metadata.h>
#include <android-base/logging.h>
#include <android-base/result.h>
#include <android-base/strings.h>
#include <hidl/metadata.h>

#include "CompatibilityMatrix.h"
#include "constants-private.h"
#include "parse_string.h"
#include "parse_xml.h"
#include "utils.h"

using std::placeholders::_1;
using std::placeholders::_2;
using std::string_literals::operator""s;

namespace android {
namespace vintf {

using namespace details;

#ifdef LIBVINTF_TARGET
static constexpr bool kIsTarget = true;
#else
static constexpr bool kIsTarget = false;
#endif

template <typename T, typename F>
static std::shared_ptr<const T> Get(const char* id, LockedSharedPtr<T>* ptr,
                                    const F& fetchAllInformation) {
    std::unique_lock<std::mutex> _lock(ptr->mutex);
    if (!ptr->fetchedOnce) {
        LOG(INFO) << id << ": Reading VINTF information.";
        ptr->object = std::make_unique<T>();
        std::string error;
        status_t status = fetchAllInformation(ptr->object.get(), &error);
        if (status == OK) {
            ptr->fetchedOnce = true;
            LOG(INFO) << id << ": Successfully processed VINTF information";
        } else {
            // Doubled because a malformed error std::string might cause us to
            // lose the status.
            LOG(ERROR) << id << ": status from fetching VINTF information: " << status;
            LOG(ERROR) << id << ": " << status << " VINTF parse error: " << error;
            ptr->object = nullptr;  // frees the old object
        }
    }
    return ptr->object;
}

static std::unique_ptr<FileSystem> createDefaultFileSystem() {
    std::unique_ptr<FileSystem> fileSystem;
    if (kIsTarget) {
        fileSystem = std::make_unique<details::FileSystemImpl>();
    } else {
        fileSystem = std::make_unique<details::FileSystemNoOp>();
    }
    return fileSystem;
}

static std::unique_ptr<PropertyFetcher> createDefaultPropertyFetcher() {
    std::unique_ptr<PropertyFetcher> propertyFetcher;
    if (kIsTarget) {
        propertyFetcher = std::make_unique<details::PropertyFetcherImpl>();
    } else {
        propertyFetcher = std::make_unique<details::PropertyFetcherNoOp>();
    }
    return propertyFetcher;
}

std::shared_ptr<VintfObject> VintfObject::GetInstance() {
    static details::LockedSharedPtr<VintfObject> sInstance{};
    std::unique_lock<std::mutex> lock(sInstance.mutex);
    if (sInstance.object == nullptr) {
        sInstance.object = std::shared_ptr<VintfObject>(VintfObject::Builder().build().release());
    }
    return sInstance.object;
}

std::shared_ptr<const HalManifest> VintfObject::GetDeviceHalManifest() {
    return GetInstance()->getDeviceHalManifest();
}

std::shared_ptr<const HalManifest> VintfObject::getDeviceHalManifest() {
    return Get(__func__, &mDeviceManifest,
               std::bind(&VintfObject::fetchDeviceHalManifest, this, _1, _2));
}

std::shared_ptr<const HalManifest> VintfObject::GetFrameworkHalManifest() {
    return GetInstance()->getFrameworkHalManifest();
}

std::shared_ptr<const HalManifest> VintfObject::getFrameworkHalManifest() {
    return Get(__func__, &mFrameworkManifest,
               std::bind(&VintfObject::fetchFrameworkHalManifest, this, _1, _2));
}

std::shared_ptr<const CompatibilityMatrix> VintfObject::GetDeviceCompatibilityMatrix() {
    return GetInstance()->getDeviceCompatibilityMatrix();
}

std::shared_ptr<const CompatibilityMatrix> VintfObject::getDeviceCompatibilityMatrix() {
    return Get(__func__, &mDeviceMatrix, std::bind(&VintfObject::fetchDeviceMatrix, this, _1, _2));
}

std::shared_ptr<const CompatibilityMatrix> VintfObject::GetFrameworkCompatibilityMatrix() {
    return GetInstance()->getFrameworkCompatibilityMatrix();
}

std::shared_ptr<const CompatibilityMatrix> VintfObject::getFrameworkCompatibilityMatrix() {
    // To avoid deadlock, get device manifest before any locks.
    auto deviceManifest = getDeviceHalManifest();

    std::unique_lock<std::mutex> _lock(mFrameworkCompatibilityMatrixMutex);

    auto combined =
        Get(__func__, &mCombinedFrameworkMatrix,
            std::bind(&VintfObject::getCombinedFrameworkMatrix, this, deviceManifest, _1, _2));
    if (combined != nullptr) {
        return combined;
    }

    return Get(__func__, &mFrameworkMatrix,
               std::bind(&CompatibilityMatrix::fetchAllInformation, _1, getFileSystem().get(),
                         kSystemLegacyMatrix, _2));
}

status_t VintfObject::getCombinedFrameworkMatrix(
    const std::shared_ptr<const HalManifest>& deviceManifest, CompatibilityMatrix* out,
    std::string* error) {
    std::vector<CompatibilityMatrix> matrixFragments;
    auto matrixFragmentsStatus = getAllFrameworkMatrixLevels(&matrixFragments, error);
    if (matrixFragmentsStatus != OK) {
        return matrixFragmentsStatus;
    }
    if (matrixFragments.empty()) {
        if (error && error->empty()) {
            *error = "Cannot get framework matrix for each FCM version for unknown error.";
        }
        return NAME_NOT_FOUND;
    }

    Level deviceLevel = Level::UNSPECIFIED;

    if (deviceManifest != nullptr) {
        deviceLevel = deviceManifest->level();
    }

    // TODO(b/70628538): Do not infer from Shipping API level.
    if (deviceLevel == Level::UNSPECIFIED) {
        auto shippingApi = getPropertyFetcher()->getUintProperty("ro.product.first_api_level", 0u);
        if (shippingApi != 0u) {
            deviceLevel = details::convertFromApiLevel(shippingApi);
        }
    }

    if (deviceLevel == Level::UNSPECIFIED) {
        // Cannot infer FCM version. Combine all matrices by assuming
        // Shipping FCM Version == min(all supported FCM Versions in the framework)
        for (auto&& fragment : matrixFragments) {
            Level fragmentLevel = fragment.level();
            if (fragmentLevel != Level::UNSPECIFIED && deviceLevel > fragmentLevel) {
                deviceLevel = fragmentLevel;
            }
        }
    }

    if (deviceLevel == Level::UNSPECIFIED) {
        // None of the fragments specify any FCM version. Should never happen except
        // for inconsistent builds.
        if (error) {
            *error = "No framework compatibility matrix files under "s + kSystemVintfDir +
                     " declare FCM version.";
        }
        return NAME_NOT_FOUND;
    }

    auto combined = CompatibilityMatrix::combine(deviceLevel, &matrixFragments, error);
    if (combined == nullptr) {
        return BAD_VALUE;
    }
    *out = std::move(*combined);
    return OK;
}

// Load and combine all of the manifests in a directory
status_t VintfObject::addDirectoryManifests(const std::string& directory, HalManifest* manifest,
                                            std::string* error) {
    std::vector<std::string> fileNames;
    status_t err = getFileSystem()->listFiles(directory, &fileNames, error);
    // if the directory isn't there, that's okay
    if (err == NAME_NOT_FOUND) return OK;
    if (err != OK) return err;

    for (const std::string& file : fileNames) {
        // Only adds HALs because all other things are added by libvintf
        // itself for now.
        HalManifest fragmentManifest;
        err = fetchOneHalManifest(directory + file, &fragmentManifest, error);
        if (err != OK) return err;

        if (!manifest->addAll(&fragmentManifest, error)) {
            if (error) {
                error->insert(0, "Cannot add manifest fragment " + directory + file + ": ");
            }
            return UNKNOWN_ERROR;
        }
    }

    return OK;
}

// Priority for loading vendor manifest:
// 1. Vendor manifest + device fragments + ODM manifest (optional) + odm fragments
// 2. Vendor manifest + device fragments
// 3. ODM manifest (optional) + odm fragments
// 4. /vendor/manifest.xml (legacy, no fragments)
// where:
// A + B means unioning <hal> tags from A and B. If B declares an override, then this takes priority
// over A.
status_t VintfObject::fetchDeviceHalManifest(HalManifest* out, std::string* error) {
    HalManifest vendorManifest;
    status_t vendorStatus = fetchVendorHalManifest(&vendorManifest, error);
    if (vendorStatus != OK && vendorStatus != NAME_NOT_FOUND) {
        return vendorStatus;
    }

    if (vendorStatus == OK) {
        *out = std::move(vendorManifest);
        status_t fragmentStatus = addDirectoryManifests(kVendorManifestFragmentDir, out, error);
        if (fragmentStatus != OK) {
            return fragmentStatus;
        }
    }

    HalManifest odmManifest;
    status_t odmStatus = fetchOdmHalManifest(&odmManifest, error);
    if (odmStatus != OK && odmStatus != NAME_NOT_FOUND) {
        return odmStatus;
    }

    if (vendorStatus == OK) {
        if (odmStatus == OK) {
            if (!out->addAll(&odmManifest, error)) {
                if (error) {
                    error->insert(0, "Cannot add ODM manifest :");
                }
                return UNKNOWN_ERROR;
            }
        }
        return addDirectoryManifests(kOdmManifestFragmentDir, out, error);
    }

    // vendorStatus != OK, "out" is not changed.
    if (odmStatus == OK) {
        *out = std::move(odmManifest);
        return addDirectoryManifests(kOdmManifestFragmentDir, out, error);
    }

    // Use legacy /vendor/manifest.xml
    return out->fetchAllInformation(getFileSystem().get(), kVendorLegacyManifest, error);
}

// Priority:
// 1. if {vendorSku} is defined, /vendor/etc/vintf/manifest_{vendorSku}.xml
// 2. /vendor/etc/vintf/manifest.xml
// where:
// {vendorSku} is the value of ro.boot.product.vendor.sku
status_t VintfObject::fetchVendorHalManifest(HalManifest* out, std::string* error) {
    status_t status;

    std::string vendorSku;
    vendorSku = getPropertyFetcher()->getProperty("ro.boot.product.vendor.sku", "");

    if (!vendorSku.empty()) {
        status =
            fetchOneHalManifest(kVendorVintfDir + "manifest_"s + vendorSku + ".xml", out, error);
        if (status == OK || status != NAME_NOT_FOUND) {
            return status;
        }
    }

    status = fetchOneHalManifest(kVendorManifest, out, error);
    if (status == OK || status != NAME_NOT_FOUND) {
        return status;
    }

    return NAME_NOT_FOUND;
}

// "out" is written to iff return status is OK.
// Priority:
// 1. if {sku} is defined, /odm/etc/vintf/manifest_{sku}.xml
// 2. /odm/etc/vintf/manifest.xml
// 3. if {sku} is defined, /odm/etc/manifest_{sku}.xml
// 4. /odm/etc/manifest.xml
// where:
// {sku} is the value of ro.boot.product.hardware.sku
status_t VintfObject::fetchOdmHalManifest(HalManifest* out, std::string* error) {
    status_t status;

    std::string productModel;
    productModel = getPropertyFetcher()->getProperty("ro.boot.product.hardware.sku", "");

    if (!productModel.empty()) {
        status =
            fetchOneHalManifest(kOdmVintfDir + "manifest_"s + productModel + ".xml", out, error);
        if (status == OK || status != NAME_NOT_FOUND) {
            return status;
        }
    }

    status = fetchOneHalManifest(kOdmManifest, out, error);
    if (status == OK || status != NAME_NOT_FOUND) {
        return status;
    }

    if (!productModel.empty()) {
        status = fetchOneHalManifest(kOdmLegacyVintfDir + "manifest_"s + productModel + ".xml", out,
                                     error);
        if (status == OK || status != NAME_NOT_FOUND) {
            return status;
        }
    }

    status = fetchOneHalManifest(kOdmLegacyManifest, out, error);
    if (status == OK || status != NAME_NOT_FOUND) {
        return status;
    }

    return NAME_NOT_FOUND;
}

// Fetch one manifest.xml file. "out" is written to iff return status is OK.
// Returns NAME_NOT_FOUND if file is missing.
status_t VintfObject::fetchOneHalManifest(const std::string& path, HalManifest* out,
                                          std::string* error) {
    HalManifest ret;
    status_t status = ret.fetchAllInformation(getFileSystem().get(), path, error);
    if (status == OK) {
        *out = std::move(ret);
    }
    return status;
}

status_t VintfObject::fetchDeviceMatrix(CompatibilityMatrix* out, std::string* error) {
    CompatibilityMatrix etcMatrix;
    if (etcMatrix.fetchAllInformation(getFileSystem().get(), kVendorMatrix, error) == OK) {
        *out = std::move(etcMatrix);
        return OK;
    }
    return out->fetchAllInformation(getFileSystem().get(), kVendorLegacyMatrix, error);
}

// Priority:
// 1. /system/etc/vintf/manifest.xml
//    + /system/etc/vintf/manifest/*.xml if they exist
//    + /product/etc/vintf/manifest.xml if it exists
//    + /product/etc/vintf/manifest/*.xml if they exist
// 2. (deprecated) /system/manifest.xml
status_t VintfObject::fetchUnfilteredFrameworkHalManifest(HalManifest* out, std::string* error) {
    auto systemEtcStatus = fetchOneHalManifest(kSystemManifest, out, error);
    if (systemEtcStatus == OK) {
        auto dirStatus = addDirectoryManifests(kSystemManifestFragmentDir, out, error);
        if (dirStatus != OK) {
            return dirStatus;
        }

        std::vector<std::pair<const char*, const char*>> extensions{
            {kProductManifest, kProductManifestFragmentDir},
            {kSystemExtManifest, kSystemExtManifestFragmentDir},
        };
        for (auto&& [manifestPath, frags] : extensions) {
            HalManifest halManifest;
            auto status = fetchOneHalManifest(manifestPath, &halManifest, error);
            if (status != OK && status != NAME_NOT_FOUND) {
                return status;
            }
            if (status == OK) {
                if (!out->addAll(&halManifest, error)) {
                    if (error) {
                        error->insert(0, "Cannot add "s + manifestPath + ":");
                    }
                    return UNKNOWN_ERROR;
                }
            }

            auto fragmentStatus = addDirectoryManifests(frags, out, error);
            if (fragmentStatus != OK) {
                return fragmentStatus;
            }
        }

        return OK;
    } else {
        LOG(WARNING) << "Cannot fetch " << kSystemManifest << ": "
                     << (error ? *error : strerror(-systemEtcStatus));
    }

    return out->fetchAllInformation(getFileSystem().get(), kSystemLegacyManifest, error);
}

status_t VintfObject::fetchFrameworkHalManifest(HalManifest* out, std::string* error) {
    status_t status = fetchUnfilteredFrameworkHalManifest(out, error);
    if (status != OK) {
        return status;
    }
    filterHalsByDeviceManifestLevel(out);
    return OK;
}

void VintfObject::filterHalsByDeviceManifestLevel(HalManifest* out) {
    auto deviceManifest = getDeviceHalManifest();
    if (deviceManifest == nullptr) {
        LOG(WARNING) << "Cannot fetch device manifest to determine target FCM version to "
                        "filter framework manifest HALs.";
        return;
    }
    Level deviceManifestLevel = deviceManifest->level();
    if (deviceManifestLevel == Level::UNSPECIFIED) {
        LOG(WARNING)
            << "Not filtering framework manifest HALs because target FCM version is unspecified.";
        return;
    }
    out->removeHalsIf([deviceManifestLevel](const ManifestHal& hal) {
        if (hal.getMaxLevel() == Level::UNSPECIFIED) {
            return false;
        }
        return hal.getMaxLevel() < deviceManifestLevel;
    });
}

static void appendLine(std::string* error, const std::string& message) {
    if (error != nullptr) {
        if (!error->empty()) *error += "\n";
        *error += message;
    }
}

status_t VintfObject::getOneMatrix(const std::string& path, CompatibilityMatrix* out,
                                   std::string* error) {
    std::string content;
    status_t status = getFileSystem()->fetch(path, &content, error);
    if (status != OK) {
        return status;
    }
    if (!fromXml(out, content, error)) {
        if (error) {
            error->insert(0, "Cannot parse " + path + ": ");
        }
        return BAD_VALUE;
    }
    out->setFileName(path);
    return OK;
}

status_t VintfObject::getAllFrameworkMatrixLevels(std::vector<CompatibilityMatrix>* results,
                                                  std::string* error) {
    std::vector<std::string> dirs = {
        kSystemVintfDir,
        kSystemExtVintfDir,
        kProductVintfDir,
    };
    for (const auto& dir : dirs) {
        std::vector<std::string> fileNames;
        status_t listStatus = getFileSystem()->listFiles(dir, &fileNames, error);
        if (listStatus == NAME_NOT_FOUND) {
            continue;
        }
        if (listStatus != OK) {
            return listStatus;
        }
        for (const std::string& fileName : fileNames) {
            std::string path = dir + fileName;
            CompatibilityMatrix namedMatrix;
            std::string matrixError;
            status_t matrixStatus = getOneMatrix(path, &namedMatrix, &matrixError);
            if (matrixStatus != OK) {
                // Manifests and matrices share the same dir. Client may not have enough
                // permissions to read system manifests, or may not be able to parse it.
                auto logLevel = matrixStatus == BAD_VALUE ? base::DEBUG : base::ERROR;
                LOG(logLevel) << "Framework Matrix: Ignore file " << path << ": " << matrixError;
                continue;
            }
            results->emplace_back(std::move(namedMatrix));
        }

        if (dir == kSystemVintfDir && results->empty()) {
            if (error) {
                *error = "No framework matrices under " + dir + " can be fetched or parsed.\n";
            }
            return NAME_NOT_FOUND;
        }
    }

    if (results->empty()) {
        if (error) {
            *error =
                "No framework matrices can be fetched or parsed. "
                "The following directories are searched:\n  " +
                android::base::Join(dirs, "\n  ");
        }
        return NAME_NOT_FOUND;
    }
    return OK;
}

std::shared_ptr<const RuntimeInfo> VintfObject::GetRuntimeInfo(RuntimeInfo::FetchFlags flags) {
    return GetInstance()->getRuntimeInfo(flags);
}
std::shared_ptr<const RuntimeInfo> VintfObject::getRuntimeInfo(RuntimeInfo::FetchFlags flags) {
    std::unique_lock<std::mutex> _lock(mDeviceRuntimeInfo.mutex);

    // Skip fetching information that has already been fetched previously.
    flags &= (~mDeviceRuntimeInfo.fetchedFlags);

    if (mDeviceRuntimeInfo.object == nullptr) {
        mDeviceRuntimeInfo.object = getRuntimeInfoFactory()->make_shared();
    }

    status_t status = mDeviceRuntimeInfo.object->fetchAllInformation(flags);
    if (status != OK) {
        // If only kernel FCM is needed, ignore errors when fetching RuntimeInfo because RuntimeInfo
        // is not available on host. On host, the kernel level can still be inferred from device
        // manifest.
        // If other information is needed, flag the error by returning nullptr.
        auto allExceptKernelFcm = RuntimeInfo::FetchFlag::ALL & ~RuntimeInfo::FetchFlag::KERNEL_FCM;
        bool needDeviceRuntimeInfo = flags & allExceptKernelFcm;
        if (needDeviceRuntimeInfo) {
            mDeviceRuntimeInfo.fetchedFlags &= (~flags);  // mark the fields as "not fetched"
            return nullptr;
        }
    }

    // To support devices without GKI, RuntimeInfo::fetchAllInformation does not report errors
    // if kernel level cannot be retrieved. If so, fetch kernel FCM version from device HAL
    // manifest and store it in RuntimeInfo too.
    if (flags & RuntimeInfo::FetchFlag::KERNEL_FCM) {
        Level deviceManifestKernelLevel = Level::UNSPECIFIED;
        auto manifest = getDeviceHalManifest();
        if (manifest) {
            deviceManifestKernelLevel = manifest->inferredKernelLevel();
        }
        if (deviceManifestKernelLevel != Level::UNSPECIFIED) {
            Level kernelLevel = mDeviceRuntimeInfo.object->kernelLevel();
            if (kernelLevel == Level::UNSPECIFIED) {
                mDeviceRuntimeInfo.object->setKernelLevel(deviceManifestKernelLevel);
            } else if (kernelLevel != deviceManifestKernelLevel) {
                LOG(WARNING) << "uname() reports kernel level " << kernelLevel
                             << " but device manifest sets kernel level "
                             << deviceManifestKernelLevel << ". Using kernel level " << kernelLevel;
            }
        }
    }

    mDeviceRuntimeInfo.fetchedFlags |= flags;
    return mDeviceRuntimeInfo.object;
}

int32_t VintfObject::checkCompatibility(std::string* error, CheckFlags::Type flags) {
    status_t status = OK;
    // null checks for files and runtime info
    if (getFrameworkHalManifest() == nullptr) {
        appendLine(error, "No framework manifest file from device or from update package");
        status = NO_INIT;
    }
    if (getDeviceHalManifest() == nullptr) {
        appendLine(error, "No device manifest file from device or from update package");
        status = NO_INIT;
    }
    if (getFrameworkCompatibilityMatrix() == nullptr) {
        appendLine(error, "No framework matrix file from device or from update package");
        status = NO_INIT;
    }
    if (getDeviceCompatibilityMatrix() == nullptr) {
        appendLine(error, "No device matrix file from device or from update package");
        status = NO_INIT;
    }

    if (flags.isRuntimeInfoEnabled()) {
        if (getRuntimeInfo() == nullptr) {
            appendLine(error, "No runtime info from device");
            status = NO_INIT;
        }
    }
    if (status != OK) return status;

    // compatiblity check.
    if (!getDeviceHalManifest()->checkCompatibility(*getFrameworkCompatibilityMatrix(), error)) {
        if (error) {
            error->insert(0,
                          "Device manifest and framework compatibility matrix are incompatible: ");
        }
        return INCOMPATIBLE;
    }
    if (!getFrameworkHalManifest()->checkCompatibility(*getDeviceCompatibilityMatrix(), error)) {
        if (error) {
            error->insert(0,
                          "Framework manifest and device compatibility matrix are incompatible: ");
        }
        return INCOMPATIBLE;
    }

    if (flags.isRuntimeInfoEnabled()) {
        if (!getRuntimeInfo()->checkCompatibility(*getFrameworkCompatibilityMatrix(), error,
                                                  flags)) {
            if (error) {
                error->insert(0,
                              "Runtime info and framework compatibility matrix are incompatible: ");
            }
            return INCOMPATIBLE;
        }
    }

    return COMPATIBLE;
}

namespace details {

std::vector<std::string> dumpFileList() {
    return {
        // clang-format off
        kSystemVintfDir,
        kVendorVintfDir,
        kOdmVintfDir,
        kProductVintfDir,
        kSystemExtVintfDir,
        kOdmLegacyVintfDir,
        kVendorLegacyManifest,
        kVendorLegacyMatrix,
        kSystemLegacyManifest,
        kSystemLegacyMatrix,
        // clang-format on
    };
}

}  // namespace details

bool VintfObject::IsHalDeprecated(const MatrixHal& oldMatrixHal,
                                  const CompatibilityMatrix& targetMatrix,
                                  const ListInstances& listInstances,
                                  const ChildrenMap& childrenMap, std::string* appendedError) {
    bool isDeprecated = false;
    oldMatrixHal.forEachInstance([&](const MatrixInstance& oldMatrixInstance) {
        if (IsInstanceDeprecated(oldMatrixInstance, targetMatrix, listInstances, childrenMap,
                                 appendedError)) {
            isDeprecated = true;
        }
        return true;  // continue to check next instance
    });
    return isDeprecated;
}

// Let oldMatrixInstance = package@x.y-w::interface/instancePattern.
// If any "@servedVersion::interface/servedInstance" in listInstances(package@x.y::interface)
// matches instancePattern, return true iff for all child interfaces (from
// GetListedInstanceInheritance), IsFqInstanceDeprecated returns false.
bool VintfObject::IsInstanceDeprecated(const MatrixInstance& oldMatrixInstance,
                                       const CompatibilityMatrix& targetMatrix,
                                       const ListInstances& listInstances,
                                       const ChildrenMap& childrenMap, std::string* appendedError) {
    const std::string& package = oldMatrixInstance.package();
    const Version& version = oldMatrixInstance.versionRange().minVer();
    const std::string& interface = oldMatrixInstance.interface();

    std::vector<std::string> instanceHint;
    if (!oldMatrixInstance.isRegex()) {
        instanceHint.push_back(oldMatrixInstance.exactInstance());
    }

    std::vector<std::string> accumulatedErrors;
    auto list = listInstances(package, version, interface, instanceHint);

    for (const auto& pair : list) {
        const std::string& servedInstance = pair.first;
        Version servedVersion = pair.second;
        std::string servedFqInstanceString =
            toFQNameString(package, servedVersion, interface, servedInstance);
        if (!oldMatrixInstance.matchInstance(servedInstance)) {
            // ignore unrelated instance
            continue;
        }

        auto inheritance = GetListedInstanceInheritance(package, servedVersion, interface,
                                                        servedInstance, listInstances, childrenMap);
        if (!inheritance.has_value()) {
            accumulatedErrors.push_back(inheritance.error().message());
            continue;
        }

        std::vector<std::string> errors;
        for (const auto& fqInstance : *inheritance) {
            auto result = IsFqInstanceDeprecated(targetMatrix, oldMatrixInstance.format(),
                                                 fqInstance, listInstances);
            if (result.ok()) {
                errors.clear();
                break;
            }
            errors.push_back(result.error().message());
        }

        if (errors.empty()) {
            continue;
        }
        accumulatedErrors.insert(accumulatedErrors.end(), errors.begin(), errors.end());
    }

    if (accumulatedErrors.empty()) {
        return false;
    }
    appendLine(appendedError, android::base::Join(accumulatedErrors, "\n"));
    return true;
}

// Check if fqInstance is listed in |listInstances|.
bool VintfObject::IsInstanceListed(const ListInstances& listInstances,
                                   const FqInstance& fqInstance) {
    auto list =
        listInstances(fqInstance.getPackage(), fqInstance.getVersion(), fqInstance.getInterface(),
                      {fqInstance.getInstance()} /* instanceHint*/);
    return std::any_of(list.begin(), list.end(),
                       [&](const auto& pair) { return pair.first == fqInstance.getInstance(); });
}

// Return a list of FqInstance, where each element:
// - is listed in |listInstances|; AND
// - is, or inherits from, package@version::interface/instance (as specified by |childrenMap|)
android::base::Result<std::vector<FqInstance>> VintfObject::GetListedInstanceInheritance(
    const std::string& package, const Version& version, const std::string& interface,
    const std::string& instance, const ListInstances& listInstances,
    const ChildrenMap& childrenMap) {
    FqInstance fqInstance;
    if (!fqInstance.setTo(package, version.majorVer, version.minorVer, interface, instance)) {
        return android::base::Error() << toFQNameString(package, version, interface, instance)
                                      << " is not a valid FqInstance";
    }

    if (!IsInstanceListed(listInstances, fqInstance)) {
        return {};
    }

    const FQName& fqName = fqInstance.getFqName();

    std::vector<FqInstance> ret;
    ret.push_back(fqInstance);

    auto childRange = childrenMap.equal_range(fqName.string());
    for (auto it = childRange.first; it != childRange.second; ++it) {
        const auto& childFqNameString = it->second;
        FQName childFqName;
        if (!childFqName.setTo(childFqNameString)) {
            return android::base::Error() << "Cannot parse " << childFqNameString << " as FQName";
        }
        FqInstance childFqInstance;
        if (!childFqInstance.setTo(childFqName, fqInstance.getInstance())) {
            return android::base::Error() << "Cannot merge " << childFqName.string() << "/"
                                          << fqInstance.getInstance() << " as FqInstance";
            continue;
        }
        if (!IsInstanceListed(listInstances, childFqInstance)) {
            continue;
        }
        ret.push_back(childFqInstance);
    }
    return ret;
}

// Check if |fqInstance| is in |targetMatrix|; essentially equal to
// targetMatrix.matchInstance(fqInstance), but provides richer error message. In details:
// 1. package@x.?::interface/servedInstance is not in targetMatrix; OR
// 2. package@x.z::interface/servedInstance is in targetMatrix but
//    servedInstance is not in listInstances(package@x.z::interface)
android::base::Result<void> VintfObject::IsFqInstanceDeprecated(
    const CompatibilityMatrix& targetMatrix, HalFormat format, const FqInstance& fqInstance,
    const ListInstances& listInstances) {
    // Find minimum package@x.? in target matrix, and check if instance is in target matrix.
    bool foundInstance = false;
    Version targetMatrixMinVer{SIZE_MAX, SIZE_MAX};
    targetMatrix.forEachInstanceOfPackage(
        format, fqInstance.getPackage(), [&](const auto& targetMatrixInstance) {
            if (targetMatrixInstance.versionRange().majorVer == fqInstance.getMajorVersion() &&
                targetMatrixInstance.interface() == fqInstance.getInterface() &&
                targetMatrixInstance.matchInstance(fqInstance.getInstance())) {
                targetMatrixMinVer =
                    std::min(targetMatrixMinVer, targetMatrixInstance.versionRange().minVer());
                foundInstance = true;
            }
            return true;
        });
    if (!foundInstance) {
        return android::base::Error()
               << fqInstance.string() << " is deprecated in compatibility matrix at FCM Version "
               << targetMatrix.level() << "; it should not be served.";
    }

    // Assuming that targetMatrix requires @x.u-v, require that at least @x.u is served.
    bool targetVersionServed = false;
    for (const auto& newPair :
         listInstances(fqInstance.getPackage(), targetMatrixMinVer, fqInstance.getInterface(),
                       {fqInstance.getInstance()} /* instanceHint */)) {
        if (newPair.first == fqInstance.getInstance()) {
            targetVersionServed = true;
            break;
        }
    }

    if (!targetVersionServed) {
        return android::base::Error()
               << fqInstance.string() << " is deprecated; requires at least " << targetMatrixMinVer;
    }
    return {};
}

int32_t VintfObject::checkDeprecation(const ListInstances& listInstances,
                                      const std::vector<HidlInterfaceMetadata>& hidlMetadata,
                                      std::string* error) {
    std::vector<CompatibilityMatrix> matrixFragments;
    auto matrixFragmentsStatus = getAllFrameworkMatrixLevels(&matrixFragments, error);
    if (matrixFragmentsStatus != OK) {
        return matrixFragmentsStatus;
    }
    if (matrixFragments.empty()) {
        if (error && error->empty()) {
            *error = "Cannot get framework matrix for each FCM version for unknown error.";
        }
        return NAME_NOT_FOUND;
    }
    auto deviceManifest = getDeviceHalManifest();
    if (deviceManifest == nullptr) {
        if (error) *error = "No device manifest.";
        return NAME_NOT_FOUND;
    }
    Level deviceLevel = deviceManifest->level();
    if (deviceLevel == Level::UNSPECIFIED) {
        if (error) *error = "Device manifest does not specify Shipping FCM Version.";
        return BAD_VALUE;
    }

    std::vector<CompatibilityMatrix> targetMatrices;
    // Partition matrixFragments into two groups, where the second group
    // contains all matrices whose level == deviceLevel.
    auto targetMatricesPartition = std::partition(
        matrixFragments.begin(), matrixFragments.end(),
        [&](const CompatibilityMatrix& matrix) { return matrix.level() != deviceLevel; });
    // Move these matrices into the targetMatrices vector...
    std::move(targetMatricesPartition, matrixFragments.end(), std::back_inserter(targetMatrices));
    if (targetMatrices.empty()) {
        if (error)
            *error = "Cannot find framework matrix at FCM version " + to_string(deviceLevel) + ".";
        return NAME_NOT_FOUND;
    }
    // so that they can be combined into one matrix for deprecation checking.
    auto targetMatrix = CompatibilityMatrix::combine(deviceLevel, &targetMatrices, error);
    if (targetMatrix == nullptr) {
        return BAD_VALUE;
    }

    std::multimap<std::string, std::string> childrenMap;
    for (const auto& child : hidlMetadata) {
        for (const auto& parent : child.inherited) {
            childrenMap.emplace(parent, child.name);
        }
    }

    // Find a list of possibly deprecated HALs by comparing |listInstances| with older matrices.
    // Matrices with unspecified level are considered "current".
    bool isDeprecated = false;
    for (auto it = matrixFragments.begin(); it < targetMatricesPartition; ++it) {
        const auto& namedMatrix = *it;
        if (namedMatrix.level() == Level::UNSPECIFIED) continue;
        if (namedMatrix.level() > deviceLevel) continue;
        for (const MatrixHal& hal : namedMatrix.getHals()) {
            if (IsHalDeprecated(hal, *targetMatrix, listInstances, childrenMap, error)) {
                isDeprecated = true;
            }
        }
    }

    return isDeprecated ? DEPRECATED : NO_DEPRECATED_HALS;
}

int32_t VintfObject::checkDeprecation(const std::vector<HidlInterfaceMetadata>& hidlMetadata,
                                      std::string* error) {
    using namespace std::placeholders;
    auto deviceManifest = getDeviceHalManifest();
    ListInstances inManifest =
        [&deviceManifest](const std::string& package, Version version, const std::string& interface,
                          const std::vector<std::string>& /* hintInstances */) {
            std::vector<std::pair<std::string, Version>> ret;
            deviceManifest->forEachInstanceOfInterface(
                HalFormat::HIDL, package, version, interface,
                [&ret](const ManifestInstance& manifestInstance) {
                    ret.push_back(
                        std::make_pair(manifestInstance.instance(), manifestInstance.version()));
                    return true;
                });
            return ret;
        };
    return checkDeprecation(inManifest, hidlMetadata, error);
}

Level VintfObject::getKernelLevel(std::string* error) {
    auto runtimeInfo = getRuntimeInfo(RuntimeInfo::FetchFlag::KERNEL_FCM);
    if (!runtimeInfo) {
        if (error) *error = "Cannot retrieve runtime info with kernel level.";
        return Level::UNSPECIFIED;
    }
    if (runtimeInfo->kernelLevel() != Level::UNSPECIFIED) {
        return runtimeInfo->kernelLevel();
    }
    if (error) {
        *error = "Both device manifest and kernel release do not specify kernel FCM version.";
    }
    return Level::UNSPECIFIED;
}

const std::unique_ptr<FileSystem>& VintfObject::getFileSystem() {
    return mFileSystem;
}

const std::unique_ptr<PropertyFetcher>& VintfObject::getPropertyFetcher() {
    return mPropertyFetcher;
}

const std::unique_ptr<ObjectFactory<RuntimeInfo>>& VintfObject::getRuntimeInfoFactory() {
    return mRuntimeInfoFactory;
}

android::base::Result<bool> VintfObject::hasFrameworkCompatibilityMatrixExtensions() {
    std::vector<CompatibilityMatrix> matrixFragments;
    std::string error;
    status_t status = getAllFrameworkMatrixLevels(&matrixFragments, &error);
    if (status != OK) {
        return android::base::Error(-status)
               << "Cannot get all framework matrix fragments: " << error;
    }
    for (const auto& namedMatrix : matrixFragments) {
        // Returns true if product matrix exists.
        if (android::base::StartsWith(namedMatrix.fileName(), kProductVintfDir)) {
            return true;
        }
        // Returns true if system_ext matrix exists.
        if (android::base::StartsWith(namedMatrix.fileName(), kSystemExtVintfDir)) {
            return true;
        }
        // Returns true if device system matrix exists.
        if (android::base::StartsWith(namedMatrix.fileName(), kSystemVintfDir) &&
            namedMatrix.level() == Level::UNSPECIFIED && !namedMatrix.getHals().empty()) {
            return true;
        }
    }
    return false;
}

android::base::Result<void> VintfObject::checkUnusedHals(
    const std::vector<HidlInterfaceMetadata>& hidlMetadata) {
    auto matrix = getFrameworkCompatibilityMatrix();
    if (matrix == nullptr) {
        return android::base::Error(-NAME_NOT_FOUND) << "Missing framework matrix.";
    }
    auto manifest = getDeviceHalManifest();
    if (manifest == nullptr) {
        return android::base::Error(-NAME_NOT_FOUND) << "Missing device manifest.";
    }
    auto unused = manifest->checkUnusedHals(*matrix, hidlMetadata);
    if (!unused.empty()) {
        return android::base::Error()
               << "The following instances are in the device manifest but "
               << "not specified in framework compatibility matrix: \n"
               << "    " << android::base::Join(unused, "\n    ") << "\n"
               << "Suggested fix:\n"
               << "1. Update deprecated HALs to the latest version.\n"
               << "2. Check for any typos in device manifest or framework compatibility "
               << "matrices with FCM version >= " << matrix->level() << ".\n"
               << "3. For new platform HALs, add them to any framework compatibility matrix "
               << "with FCM version >= " << matrix->level() << " where applicable.\n"
               << "4. For device-specific HALs, add to DEVICE_FRAMEWORK_COMPATIBILITY_MATRIX_FILE "
               << "or DEVICE_PRODUCT_COMPATIBILITY_MATRIX_FILE.";
    }
    return {};
}

namespace {

// Insert |name| into |ret| if shouldCheck(name).
void InsertIf(const std::string& name, const std::function<bool(const std::string&)>& shouldCheck,
              std::set<std::string>* ret) {
    if (shouldCheck(name)) ret->insert(name);
}

std::string StripHidlInterface(const std::string& fqNameString) {
    FQName fqName;
    if (!fqName.setTo(fqNameString)) {
        return "";
    }
    return fqName.getPackageAndVersion().string();
}

std::string StripAidlType(const std::string& type) {
    auto items = android::base::Split(type, ".");
    if (items.empty()) {
        return "";
    }
    items.erase(items.end() - 1);
    return android::base::Join(items, ".");
}

// android.hardware.foo@1.0
std::set<std::string> HidlMetadataToPackagesAndVersions(
    const std::vector<HidlInterfaceMetadata>& hidlMetadata,
    const std::function<bool(const std::string&)>& shouldCheck) {
    std::set<std::string> ret;
    for (const auto& item : hidlMetadata) {
        InsertIf(StripHidlInterface(item.name), shouldCheck, &ret);
    }
    return ret;
}

// android.hardware.foo
std::set<std::string> AidlMetadataToPackages(
    const std::vector<AidlInterfaceMetadata>& aidlMetadata,
    const std::function<bool(const std::string&)>& shouldCheck) {
    std::set<std::string> ret;
    for (const auto& item : aidlMetadata) {
        for (const auto& type : item.types) {
            InsertIf(StripAidlType(type), shouldCheck, &ret);
        }
    }
    return ret;
}

// android.hardware.foo@1.0::IFoo.
// Note that UDTs are not filtered out, so there might be non-interface types.
std::set<std::string> HidlMetadataToNames(const std::vector<HidlInterfaceMetadata>& hidlMetadata) {
    std::set<std::string> ret;
    for (const auto& item : hidlMetadata) {
        ret.insert(item.name);
    }
    return ret;
}

// android.hardware.foo.IFoo
// Note that UDTs are not filtered out, so there might be non-interface types.
std::set<std::string> AidlMetadataToNames(const std::vector<AidlInterfaceMetadata>& aidlMetadata) {
    std::set<std::string> ret;
    for (const auto& item : aidlMetadata) {
        for (const auto& type : item.types) {
            ret.insert(type);
        }
    }
    return ret;
}

}  // anonymous namespace

android::base::Result<std::vector<CompatibilityMatrix>> VintfObject::getAllFrameworkMatrixLevels() {
    // Get all framework matrix fragments instead of the combined framework compatibility matrix
    // because the latter may omit interfaces from the latest FCM if device target-level is not
    // the latest.
    std::vector<CompatibilityMatrix> matrixFragments;
    std::string error;
    auto matrixFragmentsStatus = getAllFrameworkMatrixLevels(&matrixFragments, &error);
    if (matrixFragmentsStatus != OK) {
        return android::base::Error(-matrixFragmentsStatus)
               << "Unable to get all framework matrix fragments: " << error;
    }
    if (matrixFragments.empty()) {
        if (error.empty()) {
            error = "Cannot get framework matrix for each FCM version for unknown error.";
        }
        return android::base::Error(-NAME_NOT_FOUND) << error;
    }
    return matrixFragments;
}

android::base::Result<void> VintfObject::checkMissingHalsInMatrices(
    const std::vector<HidlInterfaceMetadata>& hidlMetadata,
    const std::vector<AidlInterfaceMetadata>& aidlMetadata,
    std::function<bool(const std::string&)> shouldCheck) {
    if (!shouldCheck) {
        shouldCheck = [](const auto&) { return true; };
    }

    auto matrixFragments = getAllFrameworkMatrixLevels();
    if (!matrixFragments.ok()) return matrixFragments.error();

    // Filter aidlMetadata and hidlMetadata with shouldCheck.
    auto allAidlPackages = AidlMetadataToPackages(aidlMetadata, shouldCheck);
    auto allHidlPackagesAndVersions = HidlMetadataToPackagesAndVersions(hidlMetadata, shouldCheck);

    // Filter out instances in allAidlMetadata and allHidlMetadata that are in the matrices.
    std::vector<std::string> errors;
    for (const auto& matrix : matrixFragments.value()) {
        matrix.forEachInstance([&](const MatrixInstance& matrixInstance) {
            switch (matrixInstance.format()) {
                case HalFormat::AIDL: {
                    allAidlPackages.erase(matrixInstance.package());
                    return true;  // continue to next instance
                }
                case HalFormat::HIDL: {
                    for (Version v = matrixInstance.versionRange().minVer();
                         v <= matrixInstance.versionRange().maxVer(); ++v.minorVer) {
                        allHidlPackagesAndVersions.erase(
                            toFQNameString(matrixInstance.package(), v));
                    }
                    return true;  // continue to next instance
                }
                default: {
                    if (shouldCheck(matrixInstance.package())) {
                        errors.push_back("HAL package " + matrixInstance.package() +
                                         " is not allowed to have format " +
                                         to_string(matrixInstance.format()) + ".");
                    }
                    return true;  // continue to next instance
                }
            }
        });
    }

    if (!allHidlPackagesAndVersions.empty()) {
        errors.push_back(
            "The following HIDL packages are not found in any compatibility matrix fragments:\t\n" +
            android::base::Join(allHidlPackagesAndVersions, "\t\n"));
    }
    if (!allAidlPackages.empty()) {
        errors.push_back(
            "The following AIDL packages are not found in any compatibility matrix fragments:\t\n" +
            android::base::Join(allAidlPackages, "\t\n"));
    }

    if (!errors.empty()) {
        return android::base::Error() << android::base::Join(errors, "\n");
    }

    return {};
}

android::base::Result<void> VintfObject::checkMatrixHalsHasDefinition(
    const std::vector<HidlInterfaceMetadata>& hidlMetadata,
    const std::vector<AidlInterfaceMetadata>& aidlMetadata) {
    auto matrixFragments = getAllFrameworkMatrixLevels();
    if (!matrixFragments.ok()) return matrixFragments.error();

    auto allAidlNames = AidlMetadataToNames(aidlMetadata);
    auto allHidlNames = HidlMetadataToNames(hidlMetadata);
    std::set<std::string> badAidlInterfaces;
    std::set<std::string> badHidlInterfaces;

    std::vector<std::string> errors;
    for (const auto& matrix : matrixFragments.value()) {
        if (matrix.level() == Level::UNSPECIFIED) {
            LOG(INFO) << "Skip checkMatrixHalsHasDefinition() on " << matrix.fileName()
                      << " with no level.";
            continue;
        }

        matrix.forEachInstance([&](const MatrixInstance& matrixInstance) {
            switch (matrixInstance.format()) {
                case HalFormat::AIDL: {
                    auto matrixInterface =
                        toAidlFqnameString(matrixInstance.package(), matrixInstance.interface());
                    if (allAidlNames.find(matrixInterface) == allAidlNames.end()) {
                        errors.push_back(
                            "AIDL interface " + matrixInterface + " is referenced in " +
                            matrix.fileName() +
                            ", but there is no corresponding .aidl definition associated with an "
                            "aidl_interface module in this build. Typo?");
                    }
                    return true;  // continue to next instance
                }
                case HalFormat::HIDL: {
                    for (Version v = matrixInstance.versionRange().minVer();
                         v <= matrixInstance.versionRange().maxVer(); ++v.minorVer) {
                        auto matrixInterface = matrixInstance.interfaceDescription(v);
                        if (allHidlNames.find(matrixInterface) == allHidlNames.end()) {
                            errors.push_back(
                                "HIDL interface " + matrixInterface + " is referenced in " +
                                matrix.fileName() +
                                ", but there is no corresponding .hal definition associated with "
                                "a hidl_interface module in this build. Typo?");
                        }
                    }
                    return true;  // continue to next instance
                }
                default: {
                    // We do not have data for native HALs.
                    return true;  // continue to next instance
                }
            }
        });
    }

    if (!errors.empty()) {
        return android::base::Error() << android::base::Join(errors, "\n");
    }

    return {};
}

// make_unique does not work because VintfObject constructor is private.
VintfObject::Builder::Builder() : mObject(std::unique_ptr<VintfObject>(new VintfObject())) {}

VintfObject::Builder& VintfObject::Builder::setFileSystem(std::unique_ptr<FileSystem>&& e) {
    mObject->mFileSystem = std::move(e);
    return *this;
}

VintfObject::Builder& VintfObject::Builder::setRuntimeInfoFactory(
    std::unique_ptr<ObjectFactory<RuntimeInfo>>&& e) {
    mObject->mRuntimeInfoFactory = std::move(e);
    return *this;
}

VintfObject::Builder& VintfObject::Builder::setPropertyFetcher(
    std::unique_ptr<PropertyFetcher>&& e) {
    mObject->mPropertyFetcher = std::move(e);
    return *this;
}

std::unique_ptr<VintfObject> VintfObject::Builder::build() {
    if (!mObject->mFileSystem) mObject->mFileSystem = createDefaultFileSystem();
    if (!mObject->mRuntimeInfoFactory)
        mObject->mRuntimeInfoFactory = std::make_unique<ObjectFactory<RuntimeInfo>>();
    if (!mObject->mPropertyFetcher) mObject->mPropertyFetcher = createDefaultPropertyFetcher();
    return std::move(mObject);
}

}  // namespace vintf
}  // namespace android