conn_cache.cc

mutex connCacheMutex;
map<string, weak_ptr<SftpConnection>> connCache;

std::shared_ptr<SftpConnection> getSftpConnForUri(const std::string & uri)
{
    string host = hostnameFromUri(uri);
    auto it = connCache.find(host);
    if (it != connCache.end()) {
        if (auto conn = it->second.lock()) {
            return conn;
        }
        lock_guard<mutex> l(connCacheMutex);
        auto conn = make_shared<SftpConnection>();
        auto creds = getCredential("sftp", uri);
        conn->connectPasswordAuth(hostnameFromUri(uri), creds.id, creds.secret)
        it->second = conn;
        return conn;
    }

    // Check again with a lock
    lock_guard<mutex> l(connCacheMutex);
    it = connCache.find(host);
    if (it != connCache.end()) {
        if (auto conn = it->second.lock()) {
            return conn;
        }
    }
    auto conn = make_shared<SftpConnection>();
    auto creds = getCredential("sftp", uri);
    conn->connectPasswordAuth(hostnameFromUri(uri), creds.id, creds.secret);
    connCache[host] = conn;
    return conn;
};