Reuse a buffer

Emyrk · johnstcn · commit e1d589317c69 · 2022-03-31T15:46:19.000+01:00
diff --git a/coderd/authz/authztest/iterator.go b/coderd/authz/authztest/iterator.go
@@ -16,8 +16,9 @@ type iterator interface {
 
 // SetIterator is very primitive, just used to hold a place in a set.
 type SetIterator struct {
-	i   int
-	set Set
+	i      int
+	set    Set
+	buffer Set
 }
 
 func union(sets ...Set) *SetIterator {
@@ -26,8 +27,9 @@ func union(sets ...Set) *SetIterator {
 		all = append(all, set...)
 	}
 	return &SetIterator{
-		i:   0,
-		set: all,
+		i:      0,
+		set:    all,
+		buffer: make(Set, 1),
 	}
 }
 
@@ -37,7 +39,8 @@ func (si *SetIterator) Next() bool {
 }
 
 func (si *SetIterator) Permissions() Set {
-	return Set{si.set[si.i]}
+	si.buffer[0] = si.set[si.i]
+	return si.buffer
 }
 
 func (si *SetIterator) Permission() *Permission {
@@ -61,18 +64,21 @@ func (si *SetIterator) Iterator() iterator {
 }
 
 type productIterator struct {
-	i, j int
-	a    Set
-	b    Set
+	i, j   int
+	a      Set
+	b      Set
+	buffer Set
 }
 
 func product(a, b Set) *productIterator {
-	return &productIterator{
+	i := &productIterator{
 		i: 0,
 		j: 0,
 		a: a,
 		b: b,
 	}
+	i.buffer = make(Set, i.ReturnSize())
+	return i
 }
 
 func (s *productIterator) Next() bool {
@@ -88,7 +94,9 @@ func (s *productIterator) Next() bool {
 }
 
 func (s productIterator) Permissions() Set {
-	return Set{s.a[s.i], s.b[s.j]}
+	s.buffer[0] = s.a[s.i]
+	s.buffer[1] = s.b[s.j]
+	return s.buffer
 }
 
 func (s *productIterator) Reset() {
@@ -105,4 +113,4 @@ func (s *productIterator) Size() int {
 
 func (s *productIterator) Iterator() iterator {
 	return s
-}
+}

Original file line number	Diff line number	Diff line change
`@@ -16,8 +16,9 @@ type iterator interface {`
`16`	`16`
`17`	`17`	`// SetIterator is very primitive, just used to hold a place in a set.`
`18`	`18`	`type SetIterator struct {`
`19`		`- i int`
`20`		`- set Set`
	`19`	`+ i int`
	`20`	`+ set Set`
	`21`	`+ buffer Set`
`21`	`22`	`}`
`22`	`23`
`23`	`24`	`func union(sets ...Set) *SetIterator {`
`@@ -26,8 +27,9 @@ func union(sets ...Set) *SetIterator {`
`26`	`27`	`all = append(all, set...)`
`27`	`28`	`}`
`28`	`29`	`return &SetIterator{`
`29`		`- i: 0,`
`30`		`- set: all,`
	`30`	`+ i: 0,`
	`31`	`+ set: all,`
	`32`	`+ buffer: make(Set, 1),`
`31`	`33`	`}`
`32`	`34`	`}`
`33`	`35`
`@@ -37,7 +39,8 @@ func (si *SetIterator) Next() bool {`
`37`	`39`	`}`
`38`	`40`
`39`	`41`	`func (si *SetIterator) Permissions() Set {`
`40`		`- return Set{si.set[si.i]}`
	`42`	`+ si.buffer[0] = si.set[si.i]`
	`43`	`+ return si.buffer`
`41`	`44`	`}`
`42`	`45`
`43`	`46`	`func (si SetIterator) Permission() Permission {`
`@@ -61,18 +64,21 @@ func (si *SetIterator) Iterator() iterator {`
`61`	`64`	`}`
`62`	`65`
`63`	`66`	`type productIterator struct {`
`64`		`- i, j int`
`65`		`- a Set`
`66`		`- b Set`
	`67`	`+ i, j int`
	`68`	`+ a Set`
	`69`	`+ b Set`
	`70`	`+ buffer Set`
`67`	`71`	`}`
`68`	`72`
`69`	`73`	`func product(a, b Set) *productIterator {`
`70`		`- return &productIterator{`
	`74`	`+ i := &productIterator{`
`71`	`75`	`i: 0,`
`72`	`76`	`j: 0,`
`73`	`77`	`a: a,`
`74`	`78`	`b: b,`
`75`	`79`	`}`
	`80`	`+ i.buffer = make(Set, i.ReturnSize())`
	`81`	`+ return i`
`76`	`82`	`}`
`77`	`83`
`78`	`84`	`func (s *productIterator) Next() bool {`
`@@ -88,7 +94,9 @@ func (s *productIterator) Next() bool {`
`88`	`94`	`}`
`89`	`95`
`90`	`96`	`func (s productIterator) Permissions() Set {`
`91`		`- return Set{s.a[s.i], s.b[s.j]}`
	`97`	`+ s.buffer[0] = s.a[s.i]`
	`98`	`+ s.buffer[1] = s.b[s.j]`
	`99`	`+ return s.buffer`
`92`	`100`	`}`
`93`	`101`
`94`	`102`	`func (s *productIterator) Reset() {`
`@@ -105,4 +113,4 @@ func (s *productIterator) Size() int {`
`105`	`113`
`106`	`114`	`func (s *productIterator) Iterator() iterator {`
`107`	`115`	`return s`
`108`		`-}`
	`116`	`+}`