[VOL-4291] Rw-core updates for gRPC migration
Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/coreos/bbolt/cursor.go b/vendor/github.com/coreos/bbolt/cursor.go
new file mode 100644
index 0000000..98aeb44
--- /dev/null
+++ b/vendor/github.com/coreos/bbolt/cursor.go
@@ -0,0 +1,396 @@
+package bbolt
+
+import (
+ "bytes"
+ "fmt"
+ "sort"
+)
+
+// Cursor represents an iterator that can traverse over all key/value pairs in a bucket in sorted order.
+// Cursors see nested buckets with value == nil.
+// Cursors can be obtained from a transaction and are valid as long as the transaction is open.
+//
+// Keys and values returned from the cursor are only valid for the life of the transaction.
+//
+// Changing data while traversing with a cursor may cause it to be invalidated
+// and return unexpected keys and/or values. You must reposition your cursor
+// after mutating data.
+type Cursor struct {
+ bucket *Bucket
+ stack []elemRef
+}
+
+// Bucket returns the bucket that this cursor was created from.
+func (c *Cursor) Bucket() *Bucket {
+ return c.bucket
+}
+
+// First moves the cursor to the first item in the bucket and returns its key and value.
+// If the bucket is empty then a nil key and value are returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) First() (key []byte, value []byte) {
+ _assert(c.bucket.tx.db != nil, "tx closed")
+ c.stack = c.stack[:0]
+ p, n := c.bucket.pageNode(c.bucket.root)
+ c.stack = append(c.stack, elemRef{page: p, node: n, index: 0})
+ c.first()
+
+ // If we land on an empty page then move to the next value.
+ // https://github.com/boltdb/bolt/issues/450
+ if c.stack[len(c.stack)-1].count() == 0 {
+ c.next()
+ }
+
+ k, v, flags := c.keyValue()
+ if (flags & uint32(bucketLeafFlag)) != 0 {
+ return k, nil
+ }
+ return k, v
+
+}
+
+// Last moves the cursor to the last item in the bucket and returns its key and value.
+// If the bucket is empty then a nil key and value are returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) Last() (key []byte, value []byte) {
+ _assert(c.bucket.tx.db != nil, "tx closed")
+ c.stack = c.stack[:0]
+ p, n := c.bucket.pageNode(c.bucket.root)
+ ref := elemRef{page: p, node: n}
+ ref.index = ref.count() - 1
+ c.stack = append(c.stack, ref)
+ c.last()
+ k, v, flags := c.keyValue()
+ if (flags & uint32(bucketLeafFlag)) != 0 {
+ return k, nil
+ }
+ return k, v
+}
+
+// Next moves the cursor to the next item in the bucket and returns its key and value.
+// If the cursor is at the end of the bucket then a nil key and value are returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) Next() (key []byte, value []byte) {
+ _assert(c.bucket.tx.db != nil, "tx closed")
+ k, v, flags := c.next()
+ if (flags & uint32(bucketLeafFlag)) != 0 {
+ return k, nil
+ }
+ return k, v
+}
+
+// Prev moves the cursor to the previous item in the bucket and returns its key and value.
+// If the cursor is at the beginning of the bucket then a nil key and value are returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) Prev() (key []byte, value []byte) {
+ _assert(c.bucket.tx.db != nil, "tx closed")
+
+ // Attempt to move back one element until we're successful.
+ // Move up the stack as we hit the beginning of each page in our stack.
+ for i := len(c.stack) - 1; i >= 0; i-- {
+ elem := &c.stack[i]
+ if elem.index > 0 {
+ elem.index--
+ break
+ }
+ c.stack = c.stack[:i]
+ }
+
+ // If we've hit the end then return nil.
+ if len(c.stack) == 0 {
+ return nil, nil
+ }
+
+ // Move down the stack to find the last element of the last leaf under this branch.
+ c.last()
+ k, v, flags := c.keyValue()
+ if (flags & uint32(bucketLeafFlag)) != 0 {
+ return k, nil
+ }
+ return k, v
+}
+
+// Seek moves the cursor to a given key and returns it.
+// If the key does not exist then the next key is used. If no keys
+// follow, a nil key is returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) Seek(seek []byte) (key []byte, value []byte) {
+ k, v, flags := c.seek(seek)
+
+ // If we ended up after the last element of a page then move to the next one.
+ if ref := &c.stack[len(c.stack)-1]; ref.index >= ref.count() {
+ k, v, flags = c.next()
+ }
+
+ if k == nil {
+ return nil, nil
+ } else if (flags & uint32(bucketLeafFlag)) != 0 {
+ return k, nil
+ }
+ return k, v
+}
+
+// Delete removes the current key/value under the cursor from the bucket.
+// Delete fails if current key/value is a bucket or if the transaction is not writable.
+func (c *Cursor) Delete() error {
+ if c.bucket.tx.db == nil {
+ return ErrTxClosed
+ } else if !c.bucket.Writable() {
+ return ErrTxNotWritable
+ }
+
+ key, _, flags := c.keyValue()
+ // Return an error if current value is a bucket.
+ if (flags & bucketLeafFlag) != 0 {
+ return ErrIncompatibleValue
+ }
+ c.node().del(key)
+
+ return nil
+}
+
+// seek moves the cursor to a given key and returns it.
+// If the key does not exist then the next key is used.
+func (c *Cursor) seek(seek []byte) (key []byte, value []byte, flags uint32) {
+ _assert(c.bucket.tx.db != nil, "tx closed")
+
+ // Start from root page/node and traverse to correct page.
+ c.stack = c.stack[:0]
+ c.search(seek, c.bucket.root)
+
+ // If this is a bucket then return a nil value.
+ return c.keyValue()
+}
+
+// first moves the cursor to the first leaf element under the last page in the stack.
+func (c *Cursor) first() {
+ for {
+ // Exit when we hit a leaf page.
+ var ref = &c.stack[len(c.stack)-1]
+ if ref.isLeaf() {
+ break
+ }
+
+ // Keep adding pages pointing to the first element to the stack.
+ var pgid pgid
+ if ref.node != nil {
+ pgid = ref.node.inodes[ref.index].pgid
+ } else {
+ pgid = ref.page.branchPageElement(uint16(ref.index)).pgid
+ }
+ p, n := c.bucket.pageNode(pgid)
+ c.stack = append(c.stack, elemRef{page: p, node: n, index: 0})
+ }
+}
+
+// last moves the cursor to the last leaf element under the last page in the stack.
+func (c *Cursor) last() {
+ for {
+ // Exit when we hit a leaf page.
+ ref := &c.stack[len(c.stack)-1]
+ if ref.isLeaf() {
+ break
+ }
+
+ // Keep adding pages pointing to the last element in the stack.
+ var pgid pgid
+ if ref.node != nil {
+ pgid = ref.node.inodes[ref.index].pgid
+ } else {
+ pgid = ref.page.branchPageElement(uint16(ref.index)).pgid
+ }
+ p, n := c.bucket.pageNode(pgid)
+
+ var nextRef = elemRef{page: p, node: n}
+ nextRef.index = nextRef.count() - 1
+ c.stack = append(c.stack, nextRef)
+ }
+}
+
+// next moves to the next leaf element and returns the key and value.
+// If the cursor is at the last leaf element then it stays there and returns nil.
+func (c *Cursor) next() (key []byte, value []byte, flags uint32) {
+ for {
+ // Attempt to move over one element until we're successful.
+ // Move up the stack as we hit the end of each page in our stack.
+ var i int
+ for i = len(c.stack) - 1; i >= 0; i-- {
+ elem := &c.stack[i]
+ if elem.index < elem.count()-1 {
+ elem.index++
+ break
+ }
+ }
+
+ // If we've hit the root page then stop and return. This will leave the
+ // cursor on the last element of the last page.
+ if i == -1 {
+ return nil, nil, 0
+ }
+
+ // Otherwise start from where we left off in the stack and find the
+ // first element of the first leaf page.
+ c.stack = c.stack[:i+1]
+ c.first()
+
+ // If this is an empty page then restart and move back up the stack.
+ // https://github.com/boltdb/bolt/issues/450
+ if c.stack[len(c.stack)-1].count() == 0 {
+ continue
+ }
+
+ return c.keyValue()
+ }
+}
+
+// search recursively performs a binary search against a given page/node until it finds a given key.
+func (c *Cursor) search(key []byte, pgid pgid) {
+ p, n := c.bucket.pageNode(pgid)
+ if p != nil && (p.flags&(branchPageFlag|leafPageFlag)) == 0 {
+ panic(fmt.Sprintf("invalid page type: %d: %x", p.id, p.flags))
+ }
+ e := elemRef{page: p, node: n}
+ c.stack = append(c.stack, e)
+
+ // If we're on a leaf page/node then find the specific node.
+ if e.isLeaf() {
+ c.nsearch(key)
+ return
+ }
+
+ if n != nil {
+ c.searchNode(key, n)
+ return
+ }
+ c.searchPage(key, p)
+}
+
+func (c *Cursor) searchNode(key []byte, n *node) {
+ var exact bool
+ index := sort.Search(len(n.inodes), func(i int) bool {
+ // TODO(benbjohnson): Optimize this range search. It's a bit hacky right now.
+ // sort.Search() finds the lowest index where f() != -1 but we need the highest index.
+ ret := bytes.Compare(n.inodes[i].key, key)
+ if ret == 0 {
+ exact = true
+ }
+ return ret != -1
+ })
+ if !exact && index > 0 {
+ index--
+ }
+ c.stack[len(c.stack)-1].index = index
+
+ // Recursively search to the next page.
+ c.search(key, n.inodes[index].pgid)
+}
+
+func (c *Cursor) searchPage(key []byte, p *page) {
+ // Binary search for the correct range.
+ inodes := p.branchPageElements()
+
+ var exact bool
+ index := sort.Search(int(p.count), func(i int) bool {
+ // TODO(benbjohnson): Optimize this range search. It's a bit hacky right now.
+ // sort.Search() finds the lowest index where f() != -1 but we need the highest index.
+ ret := bytes.Compare(inodes[i].key(), key)
+ if ret == 0 {
+ exact = true
+ }
+ return ret != -1
+ })
+ if !exact && index > 0 {
+ index--
+ }
+ c.stack[len(c.stack)-1].index = index
+
+ // Recursively search to the next page.
+ c.search(key, inodes[index].pgid)
+}
+
+// nsearch searches the leaf node on the top of the stack for a key.
+func (c *Cursor) nsearch(key []byte) {
+ e := &c.stack[len(c.stack)-1]
+ p, n := e.page, e.node
+
+ // If we have a node then search its inodes.
+ if n != nil {
+ index := sort.Search(len(n.inodes), func(i int) bool {
+ return bytes.Compare(n.inodes[i].key, key) != -1
+ })
+ e.index = index
+ return
+ }
+
+ // If we have a page then search its leaf elements.
+ inodes := p.leafPageElements()
+ index := sort.Search(int(p.count), func(i int) bool {
+ return bytes.Compare(inodes[i].key(), key) != -1
+ })
+ e.index = index
+}
+
+// keyValue returns the key and value of the current leaf element.
+func (c *Cursor) keyValue() ([]byte, []byte, uint32) {
+ ref := &c.stack[len(c.stack)-1]
+
+ // If the cursor is pointing to the end of page/node then return nil.
+ if ref.count() == 0 || ref.index >= ref.count() {
+ return nil, nil, 0
+ }
+
+ // Retrieve value from node.
+ if ref.node != nil {
+ inode := &ref.node.inodes[ref.index]
+ return inode.key, inode.value, inode.flags
+ }
+
+ // Or retrieve value from page.
+ elem := ref.page.leafPageElement(uint16(ref.index))
+ return elem.key(), elem.value(), elem.flags
+}
+
+// node returns the node that the cursor is currently positioned on.
+func (c *Cursor) node() *node {
+ _assert(len(c.stack) > 0, "accessing a node with a zero-length cursor stack")
+
+ // If the top of the stack is a leaf node then just return it.
+ if ref := &c.stack[len(c.stack)-1]; ref.node != nil && ref.isLeaf() {
+ return ref.node
+ }
+
+ // Start from root and traverse down the hierarchy.
+ var n = c.stack[0].node
+ if n == nil {
+ n = c.bucket.node(c.stack[0].page.id, nil)
+ }
+ for _, ref := range c.stack[:len(c.stack)-1] {
+ _assert(!n.isLeaf, "expected branch node")
+ n = n.childAt(ref.index)
+ }
+ _assert(n.isLeaf, "expected leaf node")
+ return n
+}
+
+// elemRef represents a reference to an element on a given page/node.
+type elemRef struct {
+ page *page
+ node *node
+ index int
+}
+
+// isLeaf returns whether the ref is pointing at a leaf page/node.
+func (r *elemRef) isLeaf() bool {
+ if r.node != nil {
+ return r.node.isLeaf
+ }
+ return (r.page.flags & leafPageFlag) != 0
+}
+
+// count returns the number of inodes or page elements.
+func (r *elemRef) count() int {
+ if r.node != nil {
+ return len(r.node.inodes)
+ }
+ return int(r.page.count)
+}