How to pretty print concurrent queue contents in GDB?

[372046933]

For example. I have a field moodycamel::ConcurrentQueue<std::string> first_n_logs_;
print in gdb shows the following.

p (*(*(('absl::lts_20230802::container_internal::map_slot_type<int, tt::PerLearnerFirstN<200>*>'*)(tt::PerLearnerFirstN<200>::instances_.settings_ .value.slots_) + 9)).value.second).first_n_logs_ 

$13 = {static BLOCK_SIZE = 32, static EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD = 32, static EXPLICIT_INITIAL_INDEX_SIZE = 32, static IMPLICIT_INITIAL_INDEX_SIZE = 32, 
  static INITIAL_IMPLICIT_PRODUCER_HASH_SIZE = 32, static EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE = 256, static MAX_SUBQUEUE_SIZE = 18446744073709551615, 
  producerListTail = std::atomic<moodycamel::ConcurrentQueue<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, moodycamel::ConcurrentQueueDefaultTraits>::ProducerBase *> = { 0x55615a61e310 }, producerCount = std::atomic<unsigned int> = { 56 }, initialBlockPoolIndex = std::atomic<unsigned long> = { 32 }, 
  initialBlockPool = 0x556189862000, initialBlockPoolSize = 32, freeList = {
    freeListHead = std::atomic<moodycamel::ConcurrentQueue<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, moodycamel::ConcurrentQueueDefaultTraits>::Block *> = { 0x0 }, static REFS_MASK = 2147483647, static SHOULD_BE_ON_FREELIST = 2147483648}, 
  implicitProducerHash = std::atomic<moodycamel::ConcurrentQueue<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, moodycamel::ConcurrentQueueDefaultTraits>::ImplicitProducerHash *> = { 0x556158937600 }, implicitProducerHashCount = std::atomic<unsigned long> = { 56 }, initialImplicitProducerHash = {
    capacity = 32, entries = 0x5568e37771e0, prev = 0x0}, initialImplicitProducerHashEntries = {_M_elems = {{key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {
        key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 93876558397624 }, value = 0x556158758460}, {
        key = std::atomic<unsigned long> = { 93876536967352 }, value = 0x556158758f50}, {key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {
        key = std::atomic<unsigned long> = { 93876536230072 }, value = 0x556150d7bf10}, {key = std::atomic<unsigned long> = { 93876549550264 }, value = 0x5568e45a19d0}, {
        key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 93876513120440 }, value = 0x5568e45a0a10}, {
        key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 0 }, 
        value = 0x0}, {key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 93877475827896 }, value = 0x5576988ed110}, {
        key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 93876562460856 }, value = 0x5568e45a13b0}, {
        key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 93876483055800 }, value = 0x5568e3b4e620}, {
        key = std::atomic<unsigned long> = { 93876547485880 }, value = 0x5568e3b4f880}, {key = std::atomic<unsigned long> = { 93876535673016 }, value = 0x5568e3b4f960}, {
        key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {
        key = std::atomic<unsigned long> = { 93876512473272 }, value = 0x556150d7bce0}, {key = std::atomic<unsigned long> = { 93876497793208 }, value = 0x5568e45a1420}, {
        key = std::atomic<unsigned long> = { 93876517183672 }, value = 0x5568e45a0e70}, {key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {
        key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 0 }, 
        value = 0x0}, {key = std::atomic<unsigned long> = { 0 }, value = 0x0}, {key = std::atomic<unsigned long> = { 93876504813752 }, value = 0x55615a5cbc70}, {
        key = std::atomic<unsigned long> = { 93876519927992 }, value = 0x55618925a1c0}}}, implicitProducerHashResizeInProgress = {<__atomic_flag_base> = {
      _M_i = false}, <No data fields>}, nextExplicitConsumerId = std::atomic<unsigned int> = { 0 }, globalExplicitConsumerOffset = std::atomic<unsigned int> = { 0 }}

[cameron314]

It's unfortunately rather tricky to pretty-print. I started down this path with #302 but got stuck and haven't had a chance to get back to it.

[372046933]

@cameron314 Is it theoretically possible? I haven't read the source code of moody queue for now. Maybe a gdb script could do it. Just like iterating absl::flat_hash_map