store/cachekv: use typed types/kv.List instead of container/list.List

store/cachekv/memiterator.go

@@ -1,7 +1,6 @@
 package cachekv
 
 import (
-	"container/list"
 	"errors"
 
 	dbm "github.com/tendermint/tm-db"
@@ -18,13 +17,13 @@ type memIterator struct {
 	ascending  bool
 }
 
-func newMemIterator(start, end []byte, items *list.List, ascending bool) *memIterator {
+func newMemIterator(start, end []byte, items *kv.List, ascending bool) *memIterator {
 	itemsInDomain := make([]*kv.Pair, 0, items.Len())
 
 	var entered bool
 
 	for e := items.Front(); e != nil; e = e.Next() {
-		item := e.Value.(*kv.Pair)
+		item := e.Value
 		if !dbm.IsKeyInDomain(item.Key, start, end) {
 			if entered {
 				break

store/cachekv/store.go

@@ -2,7 +2,6 @@ package cachekv
 
 import (
 	"bytes"
-	"container/list"
 	"io"
 	"sort"
 	"sync"
@@ -30,7 +29,7 @@ type Store struct {
 	mtx           sync.Mutex
 	cache         map[string]*cValue
 	unsortedCache map[string]struct{}
-	sortedCache   *list.List // always ascending sorted
+	sortedCache   *kv.List // always ascending sorted
 	parent        types.KVStore
 }
 
@@ -41,7 +40,7 @@ func NewStore(parent types.KVStore) *Store {
 	return &Store{
 		cache:         make(map[string]*cValue),
 		unsortedCache: make(map[string]struct{}),
-		sortedCache:   list.New(),
+		sortedCache:   kv.NewList(),
 		parent:        parent,
 	}
 }
@@ -134,7 +133,7 @@ func (store *Store) Write() {
 	// Clear the cache
 	store.cache = make(map[string]*cValue)
 	store.unsortedCache = make(map[string]struct{})
-	store.sortedCache = list.New()
+	store.sortedCache = kv.NewList()
 }
 
 // CacheWrap implements CacheWrapper.
@@ -206,7 +205,7 @@ func (store *Store) dirtyItems(start, end []byte) {
 
 	for e := store.sortedCache.Front(); e != nil && len(unsorted) != 0; {
 		uitem := unsorted[0]
-		sitem := e.Value.(*kv.Pair)
+		sitem := e.Value
 		comp := bytes.Compare(uitem.Key, sitem.Key)
 
 		switch comp {

types/kv/kv.go

@@ -23,4 +23,6 @@ func (kvs Pairs) Less(i, j int) bool {
 }
 
 func (kvs Pairs) Swap(i, j int) { kvs.Pairs[i], kvs.Pairs[j] = kvs.Pairs[j], kvs.Pairs[i] }
-func (kvs Pairs) Sort()         { sort.Sort(kvs) }
+
+// Sort invokes sort.Sort on kvs.
+func (kvs Pairs) Sort() { sort.Sort(kvs) }

types/kv/list.go

@@ -0,0 +1,236 @@
+package kv
+
+// This code was copied from golang.org/pkg/container/list, but specially adapted
+// for use with kv.Pair to avoid the type assertion CPU expense of using Value with
+// an interface, per https://github.com/cosmos/cosmos-sdk/issues/8810
+//
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Element is an element of a linked list.
+type Element struct {
+	// Next and previous pointers in the doubly-linked list of elements.
+	// To simplify the implementation, internally a list l is implemented
+	// as a ring, such that &l.root is both the next element of the last
+	// list element (l.Back()) and the previous element of the first list
+	// element (l.Front()).
+	next, prev *Element
+
+	// The list to which this element belongs.
+	list *List
+
+	// The value stored with this element.
+	Value *Pair
+}
+
+// Next returns the next list element or nil.
+func (e *Element) Next() *Element {
+	if p := e.next; e.list != nil && p != &e.list.root {
+		return p
+	}
+	return nil
+}
+
+// Prev returns the previous list element or nil.
+func (e *Element) Prev() *Element {
+	if p := e.prev; e.list != nil && p != &e.list.root {
+		return p
+	}
+	return nil
+}
+
+// List represents a doubly linked list.
+// The zero value for List is an empty list ready to use.
+type List struct {
+	root Element // sentinel list element, only &root, root.prev, and root.next are used
+	len  int     // current list length excluding (this) sentinel element
+}
+
+// Init initializes or clears list l.
+func (l *List) Init() *List {
+	l.root.next = &l.root
+	l.root.prev = &l.root
+	l.len = 0
+	return l
+}
+
+// NewList returns an initialized list.
+func NewList() *List { return new(List).Init() }
+
+// Len returns the number of elements of list l.
+// The complexity is O(1).
+func (l *List) Len() int { return l.len }
+
+// Front returns the first element of list l or nil if the list is empty.
+func (l *List) Front() *Element {
+	if l.len == 0 {
+		return nil
+	}
+	return l.root.next
+}
+
+// Back returns the last element of list l or nil if the list is empty.
+func (l *List) Back() *Element {
+	if l.len == 0 {
+		return nil
+	}
+	return l.root.prev
+}
+
+// lazyInit lazily initializes a zero List value.
+func (l *List) lazyInit() {
+	if l.root.next == nil {
+		l.Init()
+	}
+}
+
+// insert inserts e after at, increments l.len, and returns e.
+func (l *List) insert(e, at *Element) *Element {
+	e.prev = at
+	e.next = at.next
+	e.prev.next = e
+	e.next.prev = e
+	e.list = l
+	l.len++
+	return e
+}
+
+// insertValue is a convenience wrapper for insert(&Element{Value: v}, at).
+func (l *List) insertValue(v *Pair, at *Element) *Element {
+	return l.insert(&Element{Value: v}, at)
+}
+
+// remove removes e from its list, decrements l.len, and returns e.
+func (l *List) remove(e *Element) *Element {
+	e.prev.next = e.next
+	e.next.prev = e.prev
+	e.next = nil // avoid memory leaks
+	e.prev = nil // avoid memory leaks
+	e.list = nil
+	l.len--
+	return e
+}
+
+// move moves e to next to at and returns e.
+// nolint: unparam
+func (l *List) move(e, at *Element) *Element {
+	if e == at {
+		return e
+	}
+	e.prev.next = e.next
+	e.next.prev = e.prev
+
+	e.prev = at
+	e.next = at.next
+	e.prev.next = e
+	e.next.prev = e
+
+	return e
+}
+
+// Remove removes e from l if e is an element of list l.
+// It returns the element value e.Value.
+// The element must not be nil.
+func (l *List) Remove(e *Element) *Pair {
+	if e.list == l {
+		// if e.list == l, l must have been initialized when e was inserted
+		// in l or l == nil (e is a zero Element) and l.remove will crash
+		l.remove(e)
+	}
+	return e.Value
+}
+
+// PushFront inserts a new element e with value v at the front of list l and returns e.
+func (l *List) PushFront(v *Pair) *Element {
+	l.lazyInit()
+	return l.insertValue(v, &l.root)
+}
+
+// PushBack inserts a new element e with value v at the back of list l and returns e.
+func (l *List) PushBack(v *Pair) *Element {
+	l.lazyInit()
+	return l.insertValue(v, l.root.prev)
+}
+
+// InsertBefore inserts a new element e with value v immediately before mark and returns e.
+// If mark is not an element of l, the list is not modified.
+// The mark must not be nil.
+func (l *List) InsertBefore(v *Pair, mark *Element) *Element {
+	if mark.list != l {
+		return nil
+	}
+	// see comment in List.Remove about initialization of l
+	return l.insertValue(v, mark.prev)
+}
+
+// InsertAfter inserts a new element e with value v immediately after mark and returns e.
+// If mark is not an element of l, the list is not modified.
+// The mark must not be nil.
+func (l *List) InsertAfter(v *Pair, mark *Element) *Element {
+	if mark.list != l {
+		return nil
+	}
+	// see comment in List.Remove about initialization of l
+	return l.insertValue(v, mark)
+}
+
+// MoveToFront moves element e to the front of list l.
+// If e is not an element of l, the list is not modified.
+// The element must not be nil.
+func (l *List) MoveToFront(e *Element) {
+	if e.list != l || l.root.next == e {
+		return
+	}
+	// see comment in List.Remove about initialization of l
+	l.move(e, &l.root)
+}
+
+// MoveToBack moves element e to the back of list l.
+// If e is not an element of l, the list is not modified.
+// The element must not be nil.
+func (l *List) MoveToBack(e *Element) {
+	if e.list != l || l.root.prev == e {
+		return
+	}
+	// see comment in List.Remove about initialization of l
+	l.move(e, l.root.prev)
+}
+
+// MoveBefore moves element e to its new position before mark.
+// If e or mark is not an element of l, or e == mark, the list is not modified.
+// The element and mark must not be nil.
+func (l *List) MoveBefore(e, mark *Element) {
+	if e.list != l || e == mark || mark.list != l {
+		return
+	}
+	l.move(e, mark.prev)
+}
+
+// MoveAfter moves element e to its new position after mark.
+// If e or mark is not an element of l, or e == mark, the list is not modified.
+// The element and mark must not be nil.
+func (l *List) MoveAfter(e, mark *Element) {
+	if e.list != l || e == mark || mark.list != l {
+		return
+	}
+	l.move(e, mark)
+}
+
+// PushBackList inserts a copy of another list at the back of list l.
+// The lists l and other may be the same. They must not be nil.
+func (l *List) PushBackList(other *List) {
+	l.lazyInit()
+	for i, e := other.Len(), other.Front(); i > 0; i, e = i-1, e.Next() {
+		l.insertValue(e.Value, l.root.prev)
+	}
+}
+
+// PushFrontList inserts a copy of another list at the front of list l.
+// The lists l and other may be the same. They must not be nil.
+func (l *List) PushFrontList(other *List) {
+	l.lazyInit()
+	for i, e := other.Len(), other.Back(); i > 0; i, e = i-1, e.Prev() {
+		l.insertValue(e.Value, &l.root)
+	}
+}