diff options
Diffstat (limited to 'vendor/github.com/peterbourgon/diskv/index.go')
-rw-r--r-- | vendor/github.com/peterbourgon/diskv/index.go | 115 |
1 files changed, 0 insertions, 115 deletions
diff --git a/vendor/github.com/peterbourgon/diskv/index.go b/vendor/github.com/peterbourgon/diskv/index.go deleted file mode 100644 index 96fee5152..000000000 --- a/vendor/github.com/peterbourgon/diskv/index.go +++ /dev/null @@ -1,115 +0,0 @@ -package diskv - -import ( - "sync" - - "github.com/google/btree" -) - -// Index is a generic interface for things that can -// provide an ordered list of keys. -type Index interface { - Initialize(less LessFunction, keys <-chan string) - Insert(key string) - Delete(key string) - Keys(from string, n int) []string -} - -// LessFunction is used to initialize an Index of keys in a specific order. -type LessFunction func(string, string) bool - -// 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 BTree.Less interface using the btreeString's LessFunction. -func (s btreeString) Less(i btree.Item) bool { - return s.l(s.s, i.(btreeString).s) -} - -// BTreeIndex is an implementation of the Index interface using google/btree. -type BTreeIndex struct { - sync.RWMutex - LessFunction - *btree.BTree -} - -// 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.BTree = rebuild(less, keys) -} - -// Insert inserts the given key (only) into the BTree tree. -func (i *BTreeIndex) Insert(key string) { - i.Lock() - defer i.Unlock() - if i.BTree == nil || i.LessFunction == nil { - panic("uninitialized index") - } - i.BTree.ReplaceOrInsert(btreeString{s: key, l: i.LessFunction}) -} - -// Delete removes the given key (only) from the BTree tree. -func (i *BTreeIndex) Delete(key string) { - i.Lock() - defer i.Unlock() - if i.BTree == nil || i.LessFunction == nil { - panic("uninitialized index") - } - 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 *BTreeIndex) Keys(from string, n int) []string { - i.RLock() - defer i.RUnlock() - - if i.BTree == nil || i.LessFunction == nil { - panic("uninitialized index") - } - - if i.BTree.Len() <= 0 { - return []string{} - } - - btreeFrom := btreeString{s: from, l: i.LessFunction} - skipFirst := true - 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 btree.Item) bool { - keys = append(keys, i.(btreeString).s) - return len(keys) < n - } - i.BTree.AscendGreaterOrEqual(btreeFrom, iterator) - - if skipFirst && len(keys) > 0 { - keys = keys[1:] - } - - return keys -} - -// rebuildIndex does the work of regenerating the index -// with the given keys. -func rebuild(less LessFunction, keys <-chan string) *btree.BTree { - tree := btree.New(2) - for key := range keys { - tree.ReplaceOrInsert(btreeString{s: key, l: less}) - } - return tree -} |