impl/memory: Implement Queries

impl/memory/gkvlite_iter_test.go

Index: impl/memory/gkvlite_iter_test.go
diff --git a/impl/memory/gkvlite_iter_test.go b/impl/memory/gkvlite_iter_test.go
index cb22c6d8c32bdb8950b37cdb6fdc663383cc603b..bab9a4718bd1a06e57cee9b6867f6125070125d6 100644
--- a/impl/memory/gkvlite_iter_test.go
+++ b/impl/memory/gkvlite_iter_test.go
@@ -6,7 +6,6 @@ package memory
 
 import (
 	"bytes"
-	"fmt"
 	"testing"
 
 	"github.com/luci/gkvlite"
@@ -17,17 +16,15 @@ import (
 func mkNum(n int64) []byte {
 	buf := &bytes.Buffer{}
 	_, err := cmpbin.WriteInt(buf, n)
-	if err != nil {
-		panic(fmt.Errorf("your RAM is busted: %s", err))
-	}
+	memoryCorruption(err)
+
 	return buf.Bytes()
 }
 
 func readNum(data []byte) int64 {
 	ret, _, err := cmpbin.ReadInt(bytes.NewBuffer(data))
-	if err != nil {
-		panic(fmt.Errorf("your RAM is (probably) busted: %s", err))
-	}
+	memoryCorruption(err)
+
 	return ret
 }
 
@@ -43,47 +40,49 @@ func TestIterator(t *testing.T) {
 		prev = data
 	}
 
-	get := func(c C, t *iterator) int64 {
-		ret := int64(0)
+	get := func(c C, t *iterator) interface{} {
+		ret := interface{}(nil)
 		t.next(nil, func(i *gkvlite.Item) {
-			c.So(i, ShouldNotBeNil)
-			ret = readNum(i.Key)
+			if i != nil {
+				ret = readNum(i.Key)
+			}
 		})
 		return ret
 	}
 
-	skipGet := func(c C, t *iterator, skipTo int64) int64 {
-		ret := int64(0)
+	skipGet := func(c C, t *iterator, skipTo int64) interface{} {
+		ret := interface{}(nil)
 		t.next(mkNum(skipTo), func(i *gkvlite.Item) {
-			c.So(i, ShouldNotBeNil)
-			ret = readNum(i.Key)
+			if i != nil {
+				ret = readNum(i.Key)
+			}
 		})
 		return ret
 	}
 
 	Convey("Test iterator", t, func() {
 		Convey("start at nil", func(ctx C) {
-			t := newIterator(c, nil, nil)
+			t := newIterator(&iterDefinition{c: c})
 			defer t.stop()
 			So(get(ctx, t), ShouldEqual, 5)
 			So(get(ctx, t), ShouldEqual, 6)
 			So(get(ctx, t), ShouldEqual, 7)
 
-			Convey("And can skip", func() {
+			Convey("And can skip", func(ctx C) {
 				So(skipGet(ctx, t, 10), ShouldEqual, 10)
 				So(get(ctx, t), ShouldEqual, 11)
 
-				Convey("But not forever", func(c C) {
+				Convey("But not forever", func(ctx C) {
 					t.next(mkNum(200), func(i *gkvlite.Item) {
-						c.So(i, ShouldBeNil)
+						ctx.So(i, ShouldBeNil)
 					})
 					t.next(nil, func(i *gkvlite.Item) {
-						c.So(i, ShouldBeNil)
+						ctx.So(i, ShouldBeNil)
 					})
 				})
 			})
 
-			Convey("Can iterate explicitly", func() {
+			Convey("Can iterate explicitly", func(ctx C) {
 				So(skipGet(ctx, t, 7), ShouldEqual, 8)
 				So(skipGet(ctx, t, 8), ShouldEqual, 9)
 
@@ -91,27 +90,37 @@ func TestIterator(t *testing.T) {
 				So(skipGet(ctx, t, 10), ShouldEqual, 10)
 			})
 
-			Convey("Can stop", func(c C) {
+			Convey("Can stop", func(ctx C) {
 				t.stop()
 				t.next(mkNum(200), func(i *gkvlite.Item) {
-					c.So(i, ShouldBeNil)
+					ctx.So(i, ShouldBeNil)
 				})
 				t.next(nil, func(i *gkvlite.Item) {
-					c.So(i, ShouldBeNil)
+					ctx.So(i, ShouldBeNil)
 				})
 				So(t.stop, ShouldNotPanic)
 			})
 
-			Convey("Going backwards is ignored", func(c C) {
+			Convey("Going backwards is ignored", func(ctx C) {
 				So(skipGet(ctx, t, 3), ShouldEqual, 8)
 				So(get(ctx, t), ShouldEqual, 9)
 				So(skipGet(ctx, t, 20), ShouldEqual, 20)
 				So(get(ctx, t), ShouldEqual, 21)
 			})
+
+			Convey("will stop at the end of the list", func(ctx C) {
+				So(skipGet(ctx, t, 95), ShouldEqual, 95)
+				So(get(ctx, t), ShouldEqual, 96)
+				So(get(ctx, t), ShouldEqual, 97)
+				So(get(ctx, t), ShouldEqual, 98)
+				So(get(ctx, t), ShouldEqual, 99)
+				So(get(ctx, t), ShouldBeNil)
+				So(get(ctx, t), ShouldBeNil)
+			})
 		})
 
 		Convey("can have caps on both sides", func(ctx C) {
-			t := newIterator(c, mkNum(20), mkNum(25))
+			t := newIterator(&iterDefinition{c: c, start: mkNum(20), end: mkNum(25)})
 			So(get(ctx, t), ShouldEqual, 20)
 			So(get(ctx, t), ShouldEqual, 21)
 			So(get(ctx, t), ShouldEqual, 22)
@@ -123,7 +132,7 @@ func TestIterator(t *testing.T) {
 		})
 
 		Convey("can skip over starting cap", func(ctx C) {
-			t := newIterator(c, mkNum(20), mkNum(25))
+			t := newIterator(&iterDefinition{c: c, start: mkNum(20), end: mkNum(25)})
 			So(skipGet(ctx, t, 22), ShouldEqual, 22)
 			So(get(ctx, t), ShouldEqual, 23)
 			So(get(ctx, t), ShouldEqual, 24)
@@ -152,8 +161,8 @@ func TestMultiIteratorSimple(t *testing.T) {
 	valBytes := make([][]byte, len(vals))
 	for i, nms := range vals {
 		numbs := make([][]byte, len(nms))
-		for i, n := range nms {
-			numbs[i] = mkNum(n)
+		for j, n := range nms {
+			numbs[j] = mkNum(n)
 		}
 		valBytes[i] = bjoin(numbs...)
 	}
@@ -194,8 +203,8 @@ func TestMultiIteratorSimple(t *testing.T) {
 			// starting at (1, 2) (i.e. >= 2)
 			// ending at (1, 4) (i.e. < 7)
 			defs := []*iterDefinition{
-				{c, mkNum(1), mkNum(2), mkNum(7)},
-				{c, mkNum(1), mkNum(2), mkNum(7)},
+				{c: c, prefix: mkNum(1), prefixLen: len(mkNum(1)), start: mkNum(2), end: mkNum(7)},
+				{c: c, prefix: mkNum(1), prefixLen: len(mkNum(1)), start: mkNum(2), end: mkNum(7)},
 			}
 
 			i := 1
@@ -211,8 +220,8 @@ func TestMultiIteratorSimple(t *testing.T) {
 		Convey("can make empty iteration", func() {
 			// get just the (20, *) (doesn't exist)
 			defs := []*iterDefinition{
-				{c, mkNum(20), nil, nil},
-				{c, mkNum(20), nil, nil},
+				{c: c, prefix: mkNum(20)},
+				{c: c, prefix: mkNum(20)},
 			}
 
 			i := 0
@@ -227,9 +236,9 @@ func TestMultiIteratorSimple(t *testing.T) {
 			// 'other' must start with 20, 'vals' must start with 1
 			// no range constraints
 			defs := []*iterDefinition{
-				{c2, mkNum(20), nil, nil},
-				{c, mkNum(1), nil, nil},
-				{c, mkNum(1), nil, nil},
+				{c: c2, prefix: mkNum(20)},
+				{c: c, prefix: mkNum(1)},
+				{c: c, prefix: mkNum(1)},
 			}
 
 			expect := []int64{2, 4}
@@ -243,8 +252,8 @@ func TestMultiIteratorSimple(t *testing.T) {
 
 		Convey("Can stop early", func() {
 			defs := []*iterDefinition{
-				{c, mkNum(1), nil, nil},
-				{c, mkNum(1), nil, nil},
+				{c: c, prefix: mkNum(1), prefixLen: len(mkNum(1))},
+				{c: c, prefix: mkNum(1), prefixLen: len(mkNum(1))},
 			}
 
 			i := 0