update all downstream dependencies

no specific features I'm looking to add, just keeping thing up to date.
Unit tests and my manual testing seems like everything is still working
as expected.

vendor/github.com/peterbourgon/diskv/index.go

@@ -3,7 +3,7 @@ package diskv
 import (
 	"sync"
 
-	"github.com/petar/GoLLRB/llrb"
+	"github.com/google/btree"
 )
 
 // Index is a generic interface for things that can
@@ -18,85 +18,84 @@ type Index interface {
 // LessFunction is used to initialize an Index of keys in a specific order.
 type LessFunction func(string, string) bool
 
-// llrbString is a custom data type that satisfies the LLRB Less interface,
-// making the strings it wraps sortable by the LLRB package.
-type llrbString struct {
+// btreeString is a custom data type that satisfies the BTree Less interface,
+// making the strings it wraps sortable by the BTree package.
+type btreeString struct {
 	s string
 	l LessFunction
 }
 
-// Less satisfies the llrb.Less interface using the llrbString's LessFunction.
-func (s llrbString) Less(i llrb.Item) bool {
-	return s.l(s.s, i.(llrbString).s)
+// Less satisfies the BTree.Less interface using the btreeString's LessFunction.
+func (s btreeString) Less(i btree.Item) bool {
+	return s.l(s.s, i.(btreeString).s)
 }
 
-// LLRBIndex is an implementation of the Index interface
-// using Petar Maymounkov's LLRB tree.
-type LLRBIndex struct {
+// BTreeIndex is an implementation of the Index interface using google/btree.
+type BTreeIndex struct {
 	sync.RWMutex
 	LessFunction
-	*llrb.LLRB
+	*btree.BTree
 }
 
-// Initialize populates the LLRB tree with data from the keys channel,
-// according to the passed less function. It's destructive to the LLRBIndex.
-func (i *LLRBIndex) Initialize(less LessFunction, keys <-chan string) {
+// Initialize populates the BTree tree with data from the keys channel,
+// according to the passed less function. It's destructive to the BTreeIndex.
+func (i *BTreeIndex) Initialize(less LessFunction, keys <-chan string) {
 	i.Lock()
 	defer i.Unlock()
 	i.LessFunction = less
-	i.LLRB = rebuild(less, keys)
+	i.BTree = rebuild(less, keys)
 }
 
-// Insert inserts the given key (only) into the LLRB tree.
-func (i *LLRBIndex) Insert(key string) {
+// Insert inserts the given key (only) into the BTree tree.
+func (i *BTreeIndex) Insert(key string) {
 	i.Lock()
 	defer i.Unlock()
-	if i.LLRB == nil || i.LessFunction == nil {
+	if i.BTree == nil || i.LessFunction == nil {
 		panic("uninitialized index")
 	}
-	i.LLRB.ReplaceOrInsert(llrbString{s: key, l: i.LessFunction})
+	i.BTree.ReplaceOrInsert(btreeString{s: key, l: i.LessFunction})
 }
 
-// Delete removes the given key (only) from the LLRB tree.
-func (i *LLRBIndex) Delete(key string) {
+// Delete removes the given key (only) from the BTree tree.
+func (i *BTreeIndex) Delete(key string) {
 	i.Lock()
 	defer i.Unlock()
-	if i.LLRB == nil || i.LessFunction == nil {
+	if i.BTree == nil || i.LessFunction == nil {
 		panic("uninitialized index")
 	}
-	i.LLRB.Delete(llrbString{s: key, l: i.LessFunction})
+	i.BTree.Delete(btreeString{s: key, l: i.LessFunction})
 }
 
 // Keys yields a maximum of n keys in order. If the passed 'from' key is empty,
 // Keys will return the first n keys. If the passed 'from' key is non-empty, the
 // first key in the returned slice will be the key that immediately follows the
 // passed key, in key order.
-func (i *LLRBIndex) Keys(from string, n int) []string {
+func (i *BTreeIndex) Keys(from string, n int) []string {
 	i.RLock()
 	defer i.RUnlock()
 
-	if i.LLRB == nil || i.LessFunction == nil {
+	if i.BTree == nil || i.LessFunction == nil {
 		panic("uninitialized index")
 	}
 
-	if i.LLRB.Len() <= 0 {
+	if i.BTree.Len() <= 0 {
 		return []string{}
 	}
 
-	llrbFrom := llrbString{s: from, l: i.LessFunction}
+	btreeFrom := btreeString{s: from, l: i.LessFunction}
 	skipFirst := true
-	if len(from) <= 0 || !i.LLRB.Has(llrbFrom) {
-		// no such key, so start at the top
-		llrbFrom = i.LLRB.Min().(llrbString)
+	if len(from) <= 0 || !i.BTree.Has(btreeFrom) {
+		// no such key, so fabricate an always-smallest item
+		btreeFrom = btreeString{s: "", l: func(string, string) bool { return true }}
 		skipFirst = false
 	}
 
 	keys := []string{}
-	iterator := func(i llrb.Item) bool {
-		keys = append(keys, i.(llrbString).s)
+	iterator := func(i btree.Item) bool {
+		keys = append(keys, i.(btreeString).s)
 		return len(keys) < n
 	}
-	i.LLRB.AscendGreaterOrEqual(llrbFrom, iterator)
+	i.BTree.AscendGreaterOrEqual(btreeFrom, iterator)
 
 	if skipFirst && len(keys) > 0 {
 		keys = keys[1:]
@@ -107,10 +106,10 @@ func (i *LLRBIndex) Keys(from string, n int) []string {
 
 // rebuildIndex does the work of regenerating the index
 // with the given keys.
-func rebuild(less LessFunction, keys <-chan string) *llrb.LLRB {
-	tree := llrb.New()
+func rebuild(less LessFunction, keys <-chan string) *btree.BTree {
+	tree := btree.New(2)
 	for key := range keys {
-		tree.ReplaceOrInsert(llrbString{s: key, l: less})
+		tree.ReplaceOrInsert(btreeString{s: key, l: less})
 	}
 	return tree
 }