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author | Christopher Speller <crspeller@gmail.com> | 2017-08-17 17:19:06 -0700 |
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committer | GitHub <noreply@github.com> | 2017-08-17 17:19:06 -0700 |
commit | 96eab1202717e073782ec399a4e0820cae15b1bb (patch) | |
tree | 011012982be971c7e9ef91466f026bc0956ac9a2 /vendor/github.com/hashicorp/go-immutable-radix/node.go | |
parent | 2c895ee66eed626721135acfcc48254c6e3f3b29 (diff) | |
download | chat-96eab1202717e073782ec399a4e0820cae15b1bb.tar.gz chat-96eab1202717e073782ec399a4e0820cae15b1bb.tar.bz2 chat-96eab1202717e073782ec399a4e0820cae15b1bb.zip |
Updating server dependancies. (#7246)
Diffstat (limited to 'vendor/github.com/hashicorp/go-immutable-radix/node.go')
-rw-r--r-- | vendor/github.com/hashicorp/go-immutable-radix/node.go | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/node.go b/vendor/github.com/hashicorp/go-immutable-radix/node.go new file mode 100644 index 000000000..7a065e7a0 --- /dev/null +++ b/vendor/github.com/hashicorp/go-immutable-radix/node.go @@ -0,0 +1,292 @@ +package iradix + +import ( + "bytes" + "sort" +) + +// WalkFn is used when walking the tree. Takes a +// key and value, returning if iteration should +// be terminated. +type WalkFn func(k []byte, v interface{}) bool + +// leafNode is used to represent a value +type leafNode struct { + mutateCh chan struct{} + key []byte + val interface{} +} + +// edge is used to represent an edge node +type edge struct { + label byte + node *Node +} + +// Node is an immutable node in the radix tree +type Node struct { + // mutateCh is closed if this node is modified + mutateCh chan struct{} + + // leaf is used to store possible leaf + leaf *leafNode + + // prefix is the common prefix we ignore + prefix []byte + + // Edges should be stored in-order for iteration. + // We avoid a fully materialized slice to save memory, + // since in most cases we expect to be sparse + edges edges +} + +func (n *Node) isLeaf() bool { + return n.leaf != nil +} + +func (n *Node) addEdge(e edge) { + num := len(n.edges) + idx := sort.Search(num, func(i int) bool { + return n.edges[i].label >= e.label + }) + n.edges = append(n.edges, e) + if idx != num { + copy(n.edges[idx+1:], n.edges[idx:num]) + n.edges[idx] = e + } +} + +func (n *Node) replaceEdge(e edge) { + num := len(n.edges) + idx := sort.Search(num, func(i int) bool { + return n.edges[i].label >= e.label + }) + if idx < num && n.edges[idx].label == e.label { + n.edges[idx].node = e.node + return + } + panic("replacing missing edge") +} + +func (n *Node) getEdge(label byte) (int, *Node) { + num := len(n.edges) + idx := sort.Search(num, func(i int) bool { + return n.edges[i].label >= label + }) + if idx < num && n.edges[idx].label == label { + return idx, n.edges[idx].node + } + return -1, nil +} + +func (n *Node) delEdge(label byte) { + num := len(n.edges) + idx := sort.Search(num, func(i int) bool { + return n.edges[i].label >= label + }) + if idx < num && n.edges[idx].label == label { + copy(n.edges[idx:], n.edges[idx+1:]) + n.edges[len(n.edges)-1] = edge{} + n.edges = n.edges[:len(n.edges)-1] + } +} + +func (n *Node) GetWatch(k []byte) (<-chan struct{}, interface{}, bool) { + search := k + watch := n.mutateCh + for { + // Check for key exhaustion + if len(search) == 0 { + if n.isLeaf() { + return n.leaf.mutateCh, n.leaf.val, true + } + break + } + + // Look for an edge + _, n = n.getEdge(search[0]) + if n == nil { + break + } + + // Update to the finest granularity as the search makes progress + watch = n.mutateCh + + // Consume the search prefix + if bytes.HasPrefix(search, n.prefix) { + search = search[len(n.prefix):] + } else { + break + } + } + return watch, nil, false +} + +func (n *Node) Get(k []byte) (interface{}, bool) { + _, val, ok := n.GetWatch(k) + return val, ok +} + +// LongestPrefix is like Get, but instead of an +// exact match, it will return the longest prefix match. +func (n *Node) LongestPrefix(k []byte) ([]byte, interface{}, bool) { + var last *leafNode + search := k + for { + // Look for a leaf node + if n.isLeaf() { + last = n.leaf + } + + // Check for key exhaution + if len(search) == 0 { + break + } + + // Look for an edge + _, n = n.getEdge(search[0]) + if n == nil { + break + } + + // Consume the search prefix + if bytes.HasPrefix(search, n.prefix) { + search = search[len(n.prefix):] + } else { + break + } + } + if last != nil { + return last.key, last.val, true + } + return nil, nil, false +} + +// Minimum is used to return the minimum value in the tree +func (n *Node) Minimum() ([]byte, interface{}, bool) { + for { + if n.isLeaf() { + return n.leaf.key, n.leaf.val, true + } + if len(n.edges) > 0 { + n = n.edges[0].node + } else { + break + } + } + return nil, nil, false +} + +// Maximum is used to return the maximum value in the tree +func (n *Node) Maximum() ([]byte, interface{}, bool) { + for { + if num := len(n.edges); num > 0 { + n = n.edges[num-1].node + continue + } + if n.isLeaf() { + return n.leaf.key, n.leaf.val, true + } else { + break + } + } + return nil, nil, false +} + +// Iterator is used to return an iterator at +// the given node to walk the tree +func (n *Node) Iterator() *Iterator { + return &Iterator{node: n} +} + +// rawIterator is used to return a raw iterator at the given node to walk the +// tree. +func (n *Node) rawIterator() *rawIterator { + iter := &rawIterator{node: n} + iter.Next() + return iter +} + +// Walk is used to walk the tree +func (n *Node) Walk(fn WalkFn) { + recursiveWalk(n, fn) +} + +// WalkPrefix is used to walk the tree under a prefix +func (n *Node) WalkPrefix(prefix []byte, fn WalkFn) { + search := prefix + for { + // Check for key exhaution + if len(search) == 0 { + recursiveWalk(n, fn) + return + } + + // Look for an edge + _, n = n.getEdge(search[0]) + if n == nil { + break + } + + // Consume the search prefix + if bytes.HasPrefix(search, n.prefix) { + search = search[len(n.prefix):] + + } else if bytes.HasPrefix(n.prefix, search) { + // Child may be under our search prefix + recursiveWalk(n, fn) + return + } else { + break + } + } +} + +// WalkPath is used to walk the tree, but only visiting nodes +// from the root down to a given leaf. Where WalkPrefix walks +// all the entries *under* the given prefix, this walks the +// entries *above* the given prefix. +func (n *Node) WalkPath(path []byte, fn WalkFn) { + search := path + for { + // Visit the leaf values if any + if n.leaf != nil && fn(n.leaf.key, n.leaf.val) { + return + } + + // Check for key exhaution + if len(search) == 0 { + return + } + + // Look for an edge + _, n = n.getEdge(search[0]) + if n == nil { + return + } + + // Consume the search prefix + if bytes.HasPrefix(search, n.prefix) { + search = search[len(n.prefix):] + } else { + break + } + } +} + +// recursiveWalk is used to do a pre-order walk of a node +// recursively. Returns true if the walk should be aborted +func recursiveWalk(n *Node, fn WalkFn) bool { + // Visit the leaf values if any + if n.leaf != nil && fn(n.leaf.key, n.leaf.val) { + return true + } + + // Recurse on the children + for _, e := range n.edges { + if recursiveWalk(e.node, fn) { + return true + } + } + return false +} |