Function MOODYCAMEL_NO_TSAN enqueue_bulk

concurrentqueue.h:2077–2251

		
		template<AllocationMode allocMode, typename It>
		bool MOODYCAMEL_NO_TSAN 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::template is_empty<explicit_context>()) {
					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) {
						MOODYCAMEL_CONSTEXPR_IF (allocMode == CannotAlloc) {
							// Failed to allocate, undo changes (but keep injected blocks)
							pr_blockIndexFront = originalBlockIndexFront;
							pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
							this->tailBlock = startBlock == nullptr ? firstAllocatedBlock : startBlock;
							return false;
						}
						else 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;