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Remove dead code from concurrentqueue.

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This commit is contained in:
Bartosz Taudul 2019-11-05 21:40:52 +01:00
parent b5590ed197
commit ca198e44d3
1 changed files with 3 additions and 653 deletions
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656
client/tracy_concurrentqueue.h
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@ -243,7 +243,6 @@ struct ProducerToken;
struct ConsumerToken;
template<typename T, typename Traits> class ConcurrentQueue;
class ConcurrentQueueTests;
namespace details
@ -413,7 +412,6 @@ struct ProducerToken
private:
template<typename T, typename Traits> friend class ConcurrentQueue;
friend class ConcurrentQueueTests;
protected:
details::ConcurrentQueueProducerTypelessBase* producer;
@ -451,7 +449,6 @@ struct ConsumerToken
private:
template<typename T, typename Traits> friend class ConcurrentQueue;
friend class ConcurrentQueueTests;
private: // but shared with ConcurrentQueue
std::uint32_t initialOffset;
@ -562,231 +559,15 @@ public:
// Disable copying and copy assignment
ConcurrentQueue(ConcurrentQueue const&) MOODYCAMEL_DELETE_FUNCTION;
ConcurrentQueue(ConcurrentQueue&& other) MOODYCAMEL_DELETE_FUNCTION;
ConcurrentQueue& operator=(ConcurrentQueue const&) MOODYCAMEL_DELETE_FUNCTION;
// Moving is supported, but note that it is *not* a thread-safe operation.
// Nobody can use the queue while it's being moved, and the memory effects
// of that move must be propagated to other threads before they can use it.
// Note: When a queue is moved, its tokens are still valid but can only be
// used with the destination queue (i.e. semantically they are moved along
// with the queue itself).
ConcurrentQueue(ConcurrentQueue&& other) MOODYCAMEL_NOEXCEPT
: producerListTail(other.producerListTail.load(std::memory_order_relaxed)),
producerCount(other.producerCount.load(std::memory_order_relaxed)),
initialBlockPoolIndex(other.initialBlockPoolIndex.load(std::memory_order_relaxed)),
initialBlockPool(other.initialBlockPool),
initialBlockPoolSize(other.initialBlockPoolSize),
freeList(std::move(other.freeList)),
nextExplicitConsumerId(other.nextExplicitConsumerId.load(std::memory_order_relaxed)),
globalExplicitConsumerOffset(other.globalExplicitConsumerOffset.load(std::memory_order_relaxed))
{
other.producerListTail.store(nullptr, std::memory_order_relaxed);
other.producerCount.store(0, std::memory_order_relaxed);
other.nextExplicitConsumerId.store(0, std::memory_order_relaxed);
other.globalExplicitConsumerOffset.store(0, std::memory_order_relaxed);
other.initialBlockPoolIndex.store(0, std::memory_order_relaxed);
other.initialBlockPoolSize = 0;
other.initialBlockPool = nullptr;
reown_producers();
}
inline ConcurrentQueue& operator=(ConcurrentQueue&& other) MOODYCAMEL_NOEXCEPT
{
return swap_internal(other);
}
// Swaps this queue's state with the other's. Not thread-safe.
// Swapping two queues does not invalidate their tokens, however
// the tokens that were created for one queue must be used with
// only the swapped queue (i.e. the tokens are tied to the
// queue's movable state, not the object itself).
inline void swap(ConcurrentQueue& other) MOODYCAMEL_NOEXCEPT
{
swap_internal(other);
}
private:
ConcurrentQueue& swap_internal(ConcurrentQueue& other)
{
if (this == &other) {
return *this;
}
details::swap_relaxed(producerListTail, other.producerListTail);
details::swap_relaxed(producerCount, other.producerCount);
details::swap_relaxed(initialBlockPoolIndex, other.initialBlockPoolIndex);
std::swap(initialBlockPool, other.initialBlockPool);
std::swap(initialBlockPoolSize, other.initialBlockPoolSize);
freeList.swap(other.freeList);
details::swap_relaxed(nextExplicitConsumerId, other.nextExplicitConsumerId);
details::swap_relaxed(globalExplicitConsumerOffset, other.globalExplicitConsumerOffset);
reown_producers();
other.reown_producers();
return *this;
}
ConcurrentQueue& operator=(ConcurrentQueue&& other) MOODYCAMEL_DELETE_FUNCTION;
public:
// Enqueues a single item (by copying it) using an explicit producer token.
// Allocates memory if required. Only fails if memory allocation fails (or
// Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
// Thread-safe.
inline bool enqueue(producer_token_t const& token, T const& item)
{
return inner_enqueue(token, item);
}
// Enqueues a single item (by moving it, if possible) using an explicit producer token.
// Allocates memory if required. Only fails if memory allocation fails (or
// Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
// Thread-safe.
inline bool enqueue(producer_token_t const& token, T&& item)
{
return inner_enqueue(token, std::move(item));
}
tracy_force_inline T* enqueue_begin(producer_token_t const& token, index_t& currentTailIndex)
{
return inner_enqueue_begin(token, currentTailIndex);
return static_cast<ExplicitProducer*>(token.producer)->ConcurrentQueue::ExplicitProducer::enqueue_begin(currentTailIndex);
}
// Enqueues several items using an explicit producer token.
// Allocates memory if required. Only fails if memory allocation fails
// (or Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
// Note: Use std::make_move_iterator if the elements should be moved
// instead of copied.
// Thread-safe.
template<typename It>
bool enqueue_bulk(producer_token_t const& token, It itemFirst, size_t count)
{
return inner_enqueue_bulk(token, itemFirst, count);
}
// Attempts to dequeue from the queue.
// Returns false if all producer streams appeared empty at the time they
// were checked (so, the queue is likely but not guaranteed to be empty).
// Never allocates. Thread-safe.
template<typename U>
bool try_dequeue(U& item)
{
// Instead of simply trying each producer in turn (which could cause needless contention on the first
// producer), we score them heuristically.
size_t nonEmptyCount = 0;
ProducerBase* best = nullptr;
size_t bestSize = 0;
for (auto ptr = producerListTail.load(std::memory_order_acquire); nonEmptyCount < 3 && ptr != nullptr; ptr = ptr->next_prod()) {
auto size = ptr->size_approx();
if (size > 0) {
if (size > bestSize) {
bestSize = size;
best = ptr;
}
++nonEmptyCount;
}
}
// If there was at least one non-empty queue but it appears empty at the time
// we try to dequeue from it, we need to make sure every queue's been tried
if (nonEmptyCount > 0) {
if (details::cqLikely(best->dequeue(item))) {
return true;
}
for (auto ptr = producerListTail.load(std::memory_order_acquire); ptr != nullptr; ptr = ptr->next_prod()) {
if (ptr != best && ptr->dequeue(item)) {
return true;
}
}
}
return false;
}
// Attempts to dequeue from the queue.
// Returns false if all producer streams appeared empty at the time they
// were checked (so, the queue is likely but not guaranteed to be empty).
// This differs from the try_dequeue(item) method in that this one does
// not attempt to reduce contention by interleaving the order that producer
// streams are dequeued from. So, using this method can reduce overall throughput
// under contention, but will give more predictable results in single-threaded
// consumer scenarios. This is mostly only useful for internal unit tests.
// Never allocates. Thread-safe.
template<typename U>
bool try_dequeue_non_interleaved(U& item)
{
for (auto ptr = producerListTail.load(std::memory_order_acquire); ptr != nullptr; ptr = ptr->next_prod()) {
if (ptr->dequeue(item)) {
return true;
}
}
return false;
}
// Attempts to dequeue from the queue using an explicit consumer token.
// Returns false if all producer streams appeared empty at the time they
// were checked (so, the queue is likely but not guaranteed to be empty).
// Never allocates. Thread-safe.
template<typename U>
bool try_dequeue(consumer_token_t& token, U& item)
{
// The idea is roughly as follows:
// Every 256 items from one producer, make everyone rotate (increase the global offset) -> this means the highest efficiency consumer dictates the rotation speed of everyone else, more or less
// If you see that the global offset has changed, you must reset your consumption counter and move to your designated place
// If there's no items where you're supposed to be, keep moving until you find a producer with some items
// If the global offset has not changed but you've run out of items to consume, move over from your current position until you find an producer with something in it
if (token.desiredProducer == nullptr || token.lastKnownGlobalOffset != globalExplicitConsumerOffset.load(std::memory_order_relaxed)) {
if (!update_current_producer_after_rotation(token)) {
return false;
}
}
// If there was at least one non-empty queue but it appears empty at the time
// we try to dequeue from it, we need to make sure every queue's been tried
if (static_cast<ProducerBase*>(token.currentProducer)->dequeue(item)) {
if (++token.itemsConsumedFromCurrent == EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE) {
globalExplicitConsumerOffset.fetch_add(1, std::memory_order_relaxed);
}
return true;
}
auto tail = producerListTail.load(std::memory_order_acquire);
auto ptr = static_cast<ProducerBase*>(token.currentProducer)->next_prod();
if (ptr == nullptr) {
ptr = tail;
}
while (ptr != static_cast<ProducerBase*>(token.currentProducer)) {
if (ptr->dequeue(item)) {
token.currentProducer = ptr;
token.itemsConsumedFromCurrent = 1;
return true;
}
ptr = ptr->next_prod();
if (ptr == nullptr) {
ptr = tail;
}
}
return false;
}
// Attempts to dequeue several elements from the queue.
// Returns the number of items actually dequeued.
// Returns 0 if all producer streams appeared empty at the time they
// were checked (so, the queue is likely but not guaranteed to be empty).
// Never allocates. Thread-safe.
template<typename It>
size_t try_dequeue_bulk(It itemFirst, size_t max)
{
size_t count = 0;
for (auto ptr = producerListTail.load(std::memory_order_acquire); ptr != nullptr; ptr = ptr->next_prod()) {
count += ptr->dequeue_bulk(itemFirst, max - count);
if (count == max) {
break;
}
}
return count;
}
// Attempts to dequeue several elements from the queue using an explicit consumer token.
// Returns the number of items actually dequeued.
@ -886,31 +667,6 @@ public:
}
}
// Attempts to dequeue from a specific producer's inner queue.
// If you happen to know which producer you want to dequeue from, this
// is significantly faster than using the general-case try_dequeue methods.
// Returns false if the producer's queue appeared empty at the time it
// was checked (so, the queue is likely but not guaranteed to be empty).
// Never allocates. Thread-safe.
template<typename U>
inline bool try_dequeue_from_producer(producer_token_t const& producer, U& item)
{
return static_cast<ExplicitProducer*>(producer.producer)->dequeue(item);
}
// Attempts to dequeue several elements from a specific producer's inner queue.
// Returns the number of items actually dequeued.
// If you happen to know which producer you want to dequeue from, this
// is significantly faster than using the general-case try_dequeue methods.
// Returns 0 if the producer's queue appeared empty at the time it
// was checked (so, the queue is likely but not guaranteed to be empty).
// Never allocates. Thread-safe.
template<typename It>
inline size_t try_dequeue_bulk_from_producer(producer_token_t const& producer, It itemFirst, size_t max)
{
return static_cast<ExplicitProducer*>(producer.producer)->dequeue_bulk(itemFirst, max);
}
// Returns an estimate of the total number of elements currently in the queue. This
// estimate is only accurate if the queue has completely stabilized before it is called
@ -946,31 +702,12 @@ private:
friend struct ProducerToken;
friend struct ConsumerToken;
friend struct ExplicitProducer;
friend class ConcurrentQueueTests;
///////////////////////////////
// Queue methods
///////////////////////////////
template<typename U>
inline bool inner_enqueue(producer_token_t const& token, U&& element)
{
return static_cast<ExplicitProducer*>(token.producer)->ConcurrentQueue::ExplicitProducer::enqueue(std::forward<U>(element));
}
tracy_force_inline T* inner_enqueue_begin(producer_token_t const& token, index_t& currentTailIndex)
{
return static_cast<ExplicitProducer*>(token.producer)->ConcurrentQueue::ExplicitProducer::enqueue_begin(currentTailIndex);
}
template<typename It>
inline bool inner_enqueue_bulk(producer_token_t const& token, It itemFirst, size_t count)
{
return static_cast<ExplicitProducer*>(token.producer)->ConcurrentQueue::ExplicitProducer::enqueue_bulk(itemFirst, count);
}
inline bool update_current_producer_after_rotation(consumer_token_t& token)
{
// Ah, there's been a rotation, figure out where we should be!
@ -1274,12 +1011,6 @@ private:
virtual ~ProducerBase() { };
template<typename U>
inline bool dequeue(U& element)
{
return static_cast<ExplicitProducer*>(this)->dequeue(element);
}
template<typename It>
inline size_t dequeue_bulk(It& itemFirst, size_t max)
{
@ -1398,106 +1129,6 @@ private:
}
}
template<typename U>
inline bool enqueue(U&& element)
{
index_t currentTailIndex = this->tailIndex.load(std::memory_order_relaxed);
index_t newTailIndex = 1 + currentTailIndex;
if ((currentTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) == 0) {
// We reached the end of a block, start a new one
auto startBlock = this->tailBlock;
auto originalBlockIndexSlotsUsed = pr_blockIndexSlotsUsed;
if (this->tailBlock != nullptr && this->tailBlock->next->ConcurrentQueue::Block::is_empty()) {
// We can re-use the block ahead of us, it's empty!
this->tailBlock = this->tailBlock->next;
this->tailBlock->ConcurrentQueue::Block::reset_empty();
// We'll put the block on the block index (guaranteed to be room since we're conceptually removing the
// last block from it first -- except instead of removing then adding, we can just overwrite).
// Note that there must be a valid block index here, since even if allocation failed in the ctor,
// it would have been re-attempted when adding the first block to the queue; since there is such
// a block, a block index must have been successfully allocated.
}
else {
// Whatever head value we see here is >= the last value we saw here (relatively),
// and <= its current value. Since we have the most recent tail, the head must be
// <= to it.
auto head = this->headIndex.load(std::memory_order_relaxed);
assert(!details::circular_less_than<index_t>(currentTailIndex, head));
if (!details::circular_less_than<index_t>(head, currentTailIndex + BLOCK_SIZE)
|| (MAX_SUBQUEUE_SIZE != details::const_numeric_max<size_t>::value && (MAX_SUBQUEUE_SIZE == 0 || MAX_SUBQUEUE_SIZE - BLOCK_SIZE < currentTailIndex - head))) {
// We can't enqueue in another block because there's not enough leeway -- the
// tail could surpass the head by the time the block fills up! (Or we'll exceed
// the size limit, if the second part of the condition was true.)
return false;
}
// We're going to need a new block; check that the block index has room
if (pr_blockIndexRaw == nullptr || pr_blockIndexSlotsUsed == pr_blockIndexSize) {
// Hmm, the circular block index is already full -- we'll need
// to allocate a new index. Note pr_blockIndexRaw can only be nullptr if
// the initial allocation failed in the constructor.
if (!new_block_index(pr_blockIndexSlotsUsed)) {
return false;
}
}
// Insert a new block in the circular linked list
auto newBlock = this->parent->ConcurrentQueue::requisition_block();
if (newBlock == nullptr) {
return false;
}
newBlock->ConcurrentQueue::Block::reset_empty();
if (this->tailBlock == nullptr) {
newBlock->next = newBlock;
}
else {
newBlock->next = this->tailBlock->next;
this->tailBlock->next = newBlock;
}
this->tailBlock = newBlock;
++pr_blockIndexSlotsUsed;
}
if (!MOODYCAMEL_NOEXCEPT_CTOR(T, U, new (nullptr) T(std::forward<U>(element)))) {
// The constructor may throw. We want the element not to appear in the queue in
// that case (without corrupting the queue):
MOODYCAMEL_TRY {
new ((*this->tailBlock)[currentTailIndex]) T(std::forward<U>(element));
}
MOODYCAMEL_CATCH (...) {
// Revert change to the current block, but leave the new block available
// for next time
pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
this->tailBlock = startBlock == nullptr ? this->tailBlock : startBlock;
MOODYCAMEL_RETHROW;
}
}
else {
(void)startBlock;
(void)originalBlockIndexSlotsUsed;
}
// Add block to block index
auto& entry = blockIndex.load(std::memory_order_relaxed)->entries[pr_blockIndexFront];
entry.base = currentTailIndex;
entry.block = this->tailBlock;
blockIndex.load(std::memory_order_relaxed)->front.store(pr_blockIndexFront, std::memory_order_release);
pr_blockIndexFront = (pr_blockIndexFront + 1) & (pr_blockIndexSize - 1);
if (!MOODYCAMEL_NOEXCEPT_CTOR(T, U, new (nullptr) T(std::forward<U>(element)))) {
this->tailIndex.store(newTailIndex, std::memory_order_release);
return true;
}
}
// Enqueue
new ((*this->tailBlock)[currentTailIndex]) T(std::forward<U>(element));
this->tailIndex.store(newTailIndex, std::memory_order_release);
return true;
}
inline void enqueue_begin_alloc(index_t currentTailIndex)
{
// We reached the end of a block, start a new one
@ -1556,287 +1187,6 @@ private:
{
return this->tailIndex;
}
template<typename U>
bool dequeue(U& element)
{
auto tail = this->tailIndex.load(std::memory_order_relaxed);
auto overcommit = this->dequeueOvercommit.load(std::memory_order_relaxed);
if (details::circular_less_than<index_t>(this->dequeueOptimisticCount.load(std::memory_order_relaxed) - overcommit, tail)) {
// Might be something to dequeue, let's give it a try
// Note that this if is purely for performance purposes in the common case when the queue is
// empty and the values are eventually consistent -- we may enter here spuriously.
// Note that whatever the values of overcommit and tail are, they are not going to change (unless we
// change them) and must be the same value at this point (inside the if) as when the if condition was
// evaluated.
// We insert an acquire fence here to synchronize-with the release upon incrementing dequeueOvercommit below.
// This ensures that whatever the value we got loaded into overcommit, the load of dequeueOptisticCount in
// the fetch_add below will result in a value at least as recent as that (and therefore at least as large).
// Note that I believe a compiler (signal) fence here would be sufficient due to the nature of fetch_add (all
// read-modify-write operations are guaranteed to work on the latest value in the modification order), but
// unfortunately that can't be shown to be correct using only the C++11 standard.
// See http://stackoverflow.com/questions/18223161/what-are-the-c11-memory-ordering-guarantees-in-this-corner-case
std::atomic_thread_fence(std::memory_order_acquire);
// Increment optimistic counter, then check if it went over the boundary
auto myDequeueCount = this->dequeueOptimisticCount.fetch_add(1, std::memory_order_relaxed);
// Note that since dequeueOvercommit must be <= dequeueOptimisticCount (because dequeueOvercommit is only ever
// incremented after dequeueOptimisticCount -- this is enforced in the `else` block below), and since we now
// have a version of dequeueOptimisticCount that is at least as recent as overcommit (due to the release upon
// incrementing dequeueOvercommit and the acquire above that synchronizes with it), overcommit <= myDequeueCount.
assert(overcommit <= myDequeueCount);
// Note that we reload tail here in case it changed; it will be the same value as before or greater, since
// this load is sequenced after (happens after) the earlier load above. This is supported by read-read
// coherency (as defined in the standard), explained here: http://en.cppreference.com/w/cpp/atomic/memory_order
tail = this->tailIndex.load(std::memory_order_acquire);
if (details::cqLikely(details::circular_less_than<index_t>(myDequeueCount - overcommit, tail))) {
// Guaranteed to be at least one element to dequeue!
// Get the index. Note that since there's guaranteed to be at least one element, this
// will never exceed tail. We need to do an acquire-release fence here since it's possible
// that whatever condition got us to this point was for an earlier enqueued element (that
// we already see the memory effects for), but that by the time we increment somebody else
// has incremented it, and we need to see the memory effects for *that* element, which is
// in such a case is necessarily visible on the thread that incremented it in the first
// place with the more current condition (they must have acquired a tail that is at least
// as recent).
auto index = this->headIndex.fetch_add(1, std::memory_order_acq_rel);
// Determine which block the element is in
auto localBlockIndex = blockIndex.load(std::memory_order_acquire);
auto localBlockIndexHead = localBlockIndex->front.load(std::memory_order_acquire);
// We need to be careful here about subtracting and dividing because of index wrap-around.
// When an index wraps, we need to preserve the sign of the offset when dividing it by the
// block size (in order to get a correct signed block count offset in all cases):
auto headBase = localBlockIndex->entries[localBlockIndexHead].base;
auto blockBaseIndex = index & ~static_cast<index_t>(BLOCK_SIZE - 1);
auto offset = static_cast<size_t>(static_cast<typename std::make_signed<index_t>::type>(blockBaseIndex - headBase) / BLOCK_SIZE);
auto block = localBlockIndex->entries[(localBlockIndexHead + offset) & (localBlockIndex->size - 1)].block;
// Dequeue
auto& el = *((*block)[index]);
if (!MOODYCAMEL_NOEXCEPT_ASSIGN(T, T&&, element = std::move(el))) {
// Make sure the element is still fully dequeued and destroyed even if the assignment
// throws
struct Guard {
Block* block;
index_t index;
~Guard()
{
(*block)[index]->~T();
block->ConcurrentQueue::Block::set_empty(index);
}
} guard = { block, index };
element = std::move(el);
}
else {
element = std::move(el);
el.~T();
block->ConcurrentQueue::Block::set_empty(index);
}
return true;
}
else {
// Wasn't anything to dequeue after all; make the effective dequeue count eventually consistent
this->dequeueOvercommit.fetch_add(1, std::memory_order_release); // Release so that the fetch_add on dequeueOptimisticCount is guaranteed to happen before this write
}
}
return false;
}
template<typename It>
bool enqueue_bulk(It itemFirst, size_t count)
{
// First, we need to make sure we have enough room to enqueue all of the elements;
// this means pre-allocating blocks and putting them in the block index (but only if
// all the allocations succeeded).
index_t startTailIndex = this->tailIndex.load(std::memory_order_relaxed);
auto startBlock = this->tailBlock;
auto originalBlockIndexFront = pr_blockIndexFront;
auto originalBlockIndexSlotsUsed = pr_blockIndexSlotsUsed;
Block* firstAllocatedBlock = nullptr;
// Figure out how many blocks we'll need to allocate, and do so
size_t blockBaseDiff = ((startTailIndex + count - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1)) - ((startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1));
index_t currentTailIndex = (startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1);
if (blockBaseDiff > 0) {
// Allocate as many blocks as possible from ahead
while (blockBaseDiff > 0 && this->tailBlock != nullptr && this->tailBlock->next != firstAllocatedBlock && this->tailBlock->next->ConcurrentQueue::Block::is_empty()) {
blockBaseDiff -= static_cast<index_t>(BLOCK_SIZE);
currentTailIndex += static_cast<index_t>(BLOCK_SIZE);
this->tailBlock = this->tailBlock->next;
firstAllocatedBlock = firstAllocatedBlock == nullptr ? this->tailBlock : firstAllocatedBlock;
auto& entry = blockIndex.load(std::memory_order_relaxed)->entries[pr_blockIndexFront];
entry.base = currentTailIndex;
entry.block = this->tailBlock;
pr_blockIndexFront = (pr_blockIndexFront + 1) & (pr_blockIndexSize - 1);
}
// Now allocate as many blocks as necessary from the block pool
while (blockBaseDiff > 0) {
blockBaseDiff -= static_cast<index_t>(BLOCK_SIZE);
currentTailIndex += static_cast<index_t>(BLOCK_SIZE);
auto head = this->headIndex.load(std::memory_order_relaxed);
assert(!details::circular_less_than<index_t>(currentTailIndex, head));
bool full = !details::circular_less_than<index_t>(head, currentTailIndex + BLOCK_SIZE) || (MAX_SUBQUEUE_SIZE != details::const_numeric_max<size_t>::value && (MAX_SUBQUEUE_SIZE == 0 || MAX_SUBQUEUE_SIZE - BLOCK_SIZE < currentTailIndex - head));
if (pr_blockIndexRaw == nullptr || pr_blockIndexSlotsUsed == pr_blockIndexSize || full) {
if (full || !new_block_index(originalBlockIndexSlotsUsed)) {
// Failed to allocate, undo changes (but keep injected blocks)
pr_blockIndexFront = originalBlockIndexFront;
pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
this->tailBlock = startBlock == nullptr ? firstAllocatedBlock : startBlock;
return false;
}
// pr_blockIndexFront is updated inside new_block_index, so we need to
// update our fallback value too (since we keep the new index even if we
// later fail)
originalBlockIndexFront = originalBlockIndexSlotsUsed;
}
// Insert a new block in the circular linked list
auto newBlock = this->parent->ConcurrentQueue::requisition_block();
if (newBlock == nullptr) {
pr_blockIndexFront = originalBlockIndexFront;
pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
this->tailBlock = startBlock == nullptr ? firstAllocatedBlock : startBlock;
return false;
}
newBlock->ConcurrentQueue::Block::set_all_empty();
if (this->tailBlock == nullptr) {
newBlock->next = newBlock;
}
else {
newBlock->next = this->tailBlock->next;
this->tailBlock->next = newBlock;
}
this->tailBlock = newBlock;
firstAllocatedBlock = firstAllocatedBlock == nullptr ? this->tailBlock : firstAllocatedBlock;
++pr_blockIndexSlotsUsed;
auto& entry = blockIndex.load(std::memory_order_relaxed)->entries[pr_blockIndexFront];
entry.base = currentTailIndex;
entry.block = this->tailBlock;
pr_blockIndexFront = (pr_blockIndexFront + 1) & (pr_blockIndexSize - 1);
}
// Excellent, all allocations succeeded. Reset each block's emptiness before we fill them up, and
// publish the new block index front
auto block = firstAllocatedBlock;
while (true) {
block->ConcurrentQueue::Block::reset_empty();
if (block == this->tailBlock) {
break;
}
block = block->next;
}
if (MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (nullptr) T(details::deref_noexcept(itemFirst)))) {
blockIndex.load(std::memory_order_relaxed)->front.store((pr_blockIndexFront - 1) & (pr_blockIndexSize - 1), std::memory_order_release);
}
}
// Enqueue, one block at a time
index_t newTailIndex = startTailIndex + static_cast<index_t>(count);
currentTailIndex = startTailIndex;
auto endBlock = this->tailBlock;
this->tailBlock = startBlock;
assert((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) != 0 || firstAllocatedBlock != nullptr || count == 0);
if ((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) == 0 && firstAllocatedBlock != nullptr) {
this->tailBlock = firstAllocatedBlock;
}
while (true) {
auto stopIndex = (currentTailIndex & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
if (details::circular_less_than<index_t>(newTailIndex, stopIndex)) {
stopIndex = newTailIndex;
}
if (MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (nullptr) T(details::deref_noexcept(itemFirst)))) {
while (currentTailIndex != stopIndex) {
new ((*this->tailBlock)[currentTailIndex++]) T(*itemFirst++);
}
}
else {
MOODYCAMEL_TRY {
while (currentTailIndex != stopIndex) {
// Must use copy constructor even if move constructor is available
// because we may have to revert if there's an exception.
// Sorry about the horrible templated next line, but it was the only way
// to disable moving *at compile time*, which is important because a type
// may only define a (noexcept) move constructor, and so calls to the
// cctor will not compile, even if they are in an if branch that will never
// be executed
new ((*this->tailBlock)[currentTailIndex]) T(details::nomove_if<(bool)!MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (nullptr) T(details::deref_noexcept(itemFirst)))>::eval(*itemFirst));
++currentTailIndex;
++itemFirst;
}
}
MOODYCAMEL_CATCH (...) {
// Oh dear, an exception's been thrown -- destroy the elements that
// were enqueued so far and revert the entire bulk operation (we'll keep
// any allocated blocks in our linked list for later, though).
auto constructedStopIndex = currentTailIndex;
auto lastBlockEnqueued = this->tailBlock;
pr_blockIndexFront = originalBlockIndexFront;
pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
this->tailBlock = startBlock == nullptr ? firstAllocatedBlock : startBlock;
if (!details::is_trivially_destructible<T>::value) {
auto block = startBlock;
if ((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) == 0) {
block = firstAllocatedBlock;
}
currentTailIndex = startTailIndex;
while (true) {
stopIndex = (currentTailIndex & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
if (details::circular_less_than<index_t>(constructedStopIndex, stopIndex)) {
stopIndex = constructedStopIndex;
}
while (currentTailIndex != stopIndex) {
(*block)[currentTailIndex++]->~T();
}
if (block == lastBlockEnqueued) {
break;
}
block = block->next;
}
}
MOODYCAMEL_RETHROW;
}
}
if (this->tailBlock == endBlock) {
assert(currentTailIndex == newTailIndex);
break;
}
this->tailBlock = this->tailBlock->next;
}
if (!MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (nullptr) T(details::deref_noexcept(itemFirst))) && firstAllocatedBlock != nullptr) {
blockIndex.load(std::memory_order_relaxed)->front.store((pr_blockIndexFront - 1) & (pr_blockIndexSize - 1), std::memory_order_release);
}
this->tailIndex.store(newTailIndex, std::memory_order_release);
return true;
}
template<typename It>
size_t dequeue_bulk(It& itemFirst, size_t max)