cmd, core, eth, light, trie: add trie read caching layer

vendor/github.com/allegro/bigcache/queue/bytes_queue.go

@@ -0,0 +1,210 @@
+package queue
+
+import (
+	"encoding/binary"
+	"log"
+	"time"
+)
+
+const (
+	// Number of bytes used to keep information about entry size
+	headerEntrySize = 4
+	// Bytes before left margin are not used. Zero index means element does not exist in queue, useful while reading slice from index
+	leftMarginIndex = 1
+	// Minimum empty blob size in bytes. Empty blob fills space between tail and head in additional memory allocation.
+	// It keeps entries indexes unchanged
+	minimumEmptyBlobSize = 32 + headerEntrySize
+)
+
+// BytesQueue is a non-thread safe queue type of fifo based on bytes array.
+// For every push operation index of entry is returned. It can be used to read the entry later
+type BytesQueue struct {
+	array           []byte
+	capacity        int
+	maxCapacity     int
+	head            int
+	tail            int
+	count           int
+	rightMargin     int
+	headerBuffer    []byte
+	verbose         bool
+	initialCapacity int
+}
+
+type queueError struct {
+	message string
+}
+
+// NewBytesQueue initialize new bytes queue.
+// Initial capacity is used in bytes array allocation
+// When verbose flag is set then information about memory allocation are printed
+func NewBytesQueue(initialCapacity int, maxCapacity int, verbose bool) *BytesQueue {
+	return &BytesQueue{
+		array:           make([]byte, initialCapacity),
+		capacity:        initialCapacity,
+		maxCapacity:     maxCapacity,
+		headerBuffer:    make([]byte, headerEntrySize),
+		tail:            leftMarginIndex,
+		head:            leftMarginIndex,
+		rightMargin:     leftMarginIndex,
+		verbose:         verbose,
+		initialCapacity: initialCapacity,
+	}
+}
+
+// Reset removes all entries from queue
+func (q *BytesQueue) Reset() {
+	// Just reset indexes
+	q.tail = leftMarginIndex
+	q.head = leftMarginIndex
+	q.rightMargin = leftMarginIndex
+	q.count = 0
+}
+
+// Push copies entry at the end of queue and moves tail pointer. Allocates more space if needed.
+// Returns index for pushed data or error if maximum size queue limit is reached.
+func (q *BytesQueue) Push(data []byte) (int, error) {
+	dataLen := len(data)
+
+	if q.availableSpaceAfterTail() < dataLen+headerEntrySize {
+		if q.availableSpaceBeforeHead() >= dataLen+headerEntrySize {
+			q.tail = leftMarginIndex
+		} else if q.capacity+headerEntrySize+dataLen >= q.maxCapacity && q.maxCapacity > 0 {
+			return -1, &queueError{"Full queue. Maximum size limit reached."}
+		} else {
+			q.allocateAdditionalMemory(dataLen + headerEntrySize)
+		}
+	}
+
+	index := q.tail
+
+	q.push(data, dataLen)
+
+	return index, nil
+}
+
+func (q *BytesQueue) allocateAdditionalMemory(minimum int) {
+	start := time.Now()
+	if q.capacity < minimum {
+		q.capacity += minimum
+	}
+	q.capacity = q.capacity * 2
+	if q.capacity > q.maxCapacity && q.maxCapacity > 0 {
+		q.capacity = q.maxCapacity
+	}
+
+	oldArray := q.array
+	q.array = make([]byte, q.capacity)
+
+	if leftMarginIndex != q.rightMargin {
+		copy(q.array, oldArray[:q.rightMargin])
+
+		if q.tail < q.head {
+			emptyBlobLen := q.head - q.tail - headerEntrySize
+			q.push(make([]byte, emptyBlobLen), emptyBlobLen)
+			q.head = leftMarginIndex
+			q.tail = q.rightMargin
+		}
+	}
+
+	if q.verbose {
+		log.Printf("Allocated new queue in %s; Capacity: %d \n", time.Since(start), q.capacity)
+	}
+}
+
+func (q *BytesQueue) push(data []byte, len int) {
+	binary.LittleEndian.PutUint32(q.headerBuffer, uint32(len))
+	q.copy(q.headerBuffer, headerEntrySize)
+
+	q.copy(data, len)
+
+	if q.tail > q.head {
+		q.rightMargin = q.tail
+	}
+
+	q.count++
+}
+
+func (q *BytesQueue) copy(data []byte, len int) {
+	q.tail += copy(q.array[q.tail:], data[:len])
+}
+
+// Pop reads the oldest entry from queue and moves head pointer to the next one
+func (q *BytesQueue) Pop() ([]byte, error) {
+	data, size, err := q.peek(q.head)
+	if err != nil {
+		return nil, err
+	}
+
+	q.head += headerEntrySize + size
+	q.count--
+
+	if q.head == q.rightMargin {
+		q.head = leftMarginIndex
+		if q.tail == q.rightMargin {
+			q.tail = leftMarginIndex
+		}
+		q.rightMargin = q.tail
+	}
+
+	return data, nil
+}
+
+// Peek reads the oldest entry from list without moving head pointer
+func (q *BytesQueue) Peek() ([]byte, error) {
+	data, _, err := q.peek(q.head)
+	return data, err
+}
+
+// Get reads entry from index
+func (q *BytesQueue) Get(index int) ([]byte, error) {
+	data, _, err := q.peek(index)
+	return data, err
+}
+
+// Capacity returns number of allocated bytes for queue
+func (q *BytesQueue) Capacity() int {
+	return q.capacity
+}
+
+// Len returns number of entries kept in queue
+func (q *BytesQueue) Len() int {
+	return q.count
+}
+
+// Error returns error message
+func (e *queueError) Error() string {
+	return e.message
+}
+
+func (q *BytesQueue) peek(index int) ([]byte, int, error) {
+
+	if q.count == 0 {
+		return nil, 0, &queueError{"Empty queue"}
+	}
+
+	if index <= 0 {
+		return nil, 0, &queueError{"Index must be grater than zero. Invalid index."}
+	}
+
+	if index+headerEntrySize >= len(q.array) {
+		return nil, 0, &queueError{"Index out of range"}
+	}
+
+	blockSize := int(binary.LittleEndian.Uint32(q.array[index : index+headerEntrySize]))
+	return q.array[index+headerEntrySize : index+headerEntrySize+blockSize], blockSize, nil
+}
+
+func (q *BytesQueue) availableSpaceAfterTail() int {
+	if q.tail >= q.head {
+		return q.capacity - q.tail
+	}
+	return q.head - q.tail - minimumEmptyBlobSize
+}
+
+func (q *BytesQueue) availableSpaceBeforeHead() int {
+	if q.tail >= q.head {
+		return q.head - leftMarginIndex - minimumEmptyBlobSize
+	}
+	return q.head - q.tail - minimumEmptyBlobSize
+}