Function tryMigrateLegacyMMKVFile

Core/MMKV_Android.cpp:185–222

historically Android mistakenly use mmapKey as mmapID, we try migrate back to normal when possible

// historically Android mistakenly use mmapKey as mmapID, we try migrate back to normal when possible
MigrateStatus tryMigrateLegacyMMKVFile(const string &mmapID, const string *rootPath, bool alreadyAbsolute) {
    auto legacyID = legacyMmapedKVKey(mmapID, rootPath);
    if (legacyID == mmapID) {
        // it's not specially encoded
        return MigrateStatus::NotSpecial;
    }
    auto path = mappedKVPathWithID(legacyID, rootPath, MMKV_MULTI_PROCESS, alreadyAbsolute);
    auto targetPath = mappedKVPathWithID(mmapID, rootPath, MMKV_MULTI_PROCESS, alreadyAbsolute);
    bool oldExit = isFileExist(path);
    bool newExist = isFileExist(targetPath);
    if (oldExit) {
        if (newExist) {
            MMKVWarning("both legacy file [%s] modify: %lld ms, and new file [%s] modify: %lld ms exist",
                        path.c_str(), getFileModifyTimeInMS(path.c_str()),
                        targetPath.c_str(), getFileModifyTimeInMS(targetPath.c_str()));
            return MigrateStatus::OldAndNewExist;
        }
        auto file = File(path, OpenFlag::ReadWrite);
        if (file.isFileValid()) {
            // check if it's opened by other process
            auto fileMigrationLock = FileLock(file.getFd(), true, false, 2, 3);
            auto exclusiveMigrationLock = InterProcessLock(&fileMigrationLock, ExclusiveLockType);
            // works even if it's opened by us
            if (exclusiveMigrationLock.try_lock()) {
                if (tryAtomicRename(path, targetPath)) {
                    if (tryAtomicRename(crcPathWithPath(path), crcPathWithPath(targetPath))) {
                        MMKVInfo("Migrated legacy MMKV [%s] to [%s] in path %s", legacyID.c_str(), mmapID.c_str(), rootPath->c_str());
                        return MigrateStatus::OldToNewMigrated;
                    }
                }
            } else {
                MMKVInfo("Can't migrate legacy MMKV [%s] to [%s] in path %s, try next time.", legacyID.c_str(), mmapID.c_str(), rootPath->c_str());
            }
        }
        return MigrateStatus::OldToNewMigrateFail;
    }
    return newExist ? MigrateStatus::NewExist : MigrateStatus::NoneExist;
}

MMKV *MMKV::getMMKVWithID(const string &mmapID, const MMKVConfig &config) {
    if (mmapID.empty() || !g_instanceLock) {