Add FileEntry cache to TagCache for selfupdate.

cipd/client/cipd/internal/tagcache_test.go

Index: cipd/client/cipd/internal/tagcache_test.go
diff --git a/cipd/client/cipd/internal/tagcache_test.go b/cipd/client/cipd/internal/tagcache_test.go
index 4c9bf50c6ad60f18af3c9758406d79318a40e02f..89d496a5784064b5ab32c237e267bb7f9781aa1c 100644
--- a/cipd/client/cipd/internal/tagcache_test.go
+++ b/cipd/client/cipd/internal/tagcache_test.go
@@ -22,6 +22,16 @@ import (
 func TestTagCacheWorks(t *testing.T) {
 	ctx := context.Background()
 
+	numberedID := func(i int) string {
+		return strings.Repeat(fmt.Sprintf("%02x", i), 20)
+	}
+	numberedPin := func(i int) common.Pin {
+		return common.Pin{
+			PackageName: "pkg",
+			InstanceID:  numberedID(i),
+		}
+	}
+
 	Convey("with temp dir", t, func() {
 		tempDir, err := ioutil.TempDir("", "instanceche_test")
 		So(err, ShouldBeNil)
@@ -40,6 +50,10 @@ func TestTagCacheWorks(t *testing.T) {
 			So(err, ShouldBeNil)
 			So(pin, ShouldResemble, common.Pin{})
 
+			file, err := tc.ResolveFile(ctx, cannedPin, "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, "")
+
 			// Add new.
 			tc.AddTag(ctx, common.Pin{
 				PackageName: "pkg",
@@ -51,6 +65,10 @@ func TestTagCacheWorks(t *testing.T) {
 				PackageName: "pkg",
 				InstanceID:  strings.Repeat("a", 40),
 			})
+			tc.AddFile(ctx, cannedPin, "filename", numberedID(1))
+			file, err = tc.ResolveFile(ctx, cannedPin, "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, numberedID(1))
 
 			// Replace existing.
 			tc.AddTag(ctx, common.Pin{
@@ -63,6 +81,10 @@ func TestTagCacheWorks(t *testing.T) {
 				PackageName: "pkg",
 				InstanceID:  strings.Repeat("b", 40),
 			})
+			tc.AddFile(ctx, cannedPin, "filename", numberedID(2))
+			file, err = tc.ResolveFile(ctx, cannedPin, "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, numberedID(2))
 
 			// Save.
 			So(tc.Save(ctx), ShouldBeNil)
@@ -75,6 +97,9 @@ func TestTagCacheWorks(t *testing.T) {
 				PackageName: "pkg",
 				InstanceID:  strings.Repeat("b", 40),
 			})
+			file, err = tc.ResolveFile(ctx, cannedPin, "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, numberedID(2))
 		})
 
 		Convey("many tags", func() {
@@ -84,31 +109,47 @@ func TestTagCacheWorks(t *testing.T) {
 			for i := 0; i < tagCacheMaxSize; i++ {
 				So(tc.AddTag(ctx, cannedPin, fmt.Sprintf("tag:%d", i)), ShouldBeNil)
 			}
+			for i := 0; i < tagCacheMaxExeSize; i++ {
+				So(tc.AddFile(ctx, numberedPin(i), "filename", numberedID(i)), ShouldBeNil)
+			}
 			So(tc.Save(ctx), ShouldBeNil)
 
 			// Oldest tag is still resolvable.
 			pin, err := tc.ResolveTag(ctx, "pkg", "tag:0")
 			So(err, ShouldBeNil)
 			So(pin, ShouldResemble, cannedPin)
+			file, err := tc.ResolveFile(ctx, numberedPin(0), "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, numberedID(0))
 
 			// Add one more tag. Should evict the oldest one.
 			So(tc.AddTag(ctx, cannedPin, "one_more_tag:0"), ShouldBeNil)
+			So(tc.AddFile(ctx, numberedPin(tagCacheMaxExeSize), "filename", numberedID(tagCacheMaxExeSize)), ShouldBeNil)
 			So(tc.Save(ctx), ShouldBeNil)
 
 			// Oldest tag is evicted.
 			pin, err = tc.ResolveTag(ctx, "pkg", "tag:0")
 			So(err, ShouldBeNil)
 			So(pin, ShouldResemble, common.Pin{})
+			file, err = tc.ResolveFile(ctx, numberedPin(0), "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, "")
 
 			// But next one is alive.
 			pin, err = tc.ResolveTag(ctx, "pkg", "tag:1")
 			So(err, ShouldBeNil)
 			So(pin, ShouldResemble, cannedPin)
+			file, err = tc.ResolveFile(ctx, numberedPin(1), "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, numberedID(1))
 
 			// Most recent one is also alive.
 			pin, err = tc.ResolveTag(ctx, "pkg", "one_more_tag:0")
 			So(err, ShouldBeNil)
 			So(pin, ShouldResemble, cannedPin)
+			file, err = tc.ResolveFile(ctx, numberedPin(tagCacheMaxExeSize), "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, numberedID(tagCacheMaxExeSize))
 		})
 
 		Convey("parallel update", func() {
@@ -116,7 +157,9 @@ func TestTagCacheWorks(t *testing.T) {
 			tc2 := NewTagCache(fs)
 
 			So(tc1.AddTag(ctx, cannedPin, "tag:1"), ShouldBeNil)
+			So(tc1.AddFile(ctx, numberedPin(0), "filename", numberedID(0)), ShouldBeNil)
 			So(tc2.AddTag(ctx, cannedPin, "tag:2"), ShouldBeNil)
+			So(tc2.AddFile(ctx, numberedPin(1), "filename", numberedID(1)), ShouldBeNil)
 
 			So(tc1.Save(ctx), ShouldBeNil)
 			So(tc2.Save(ctx), ShouldBeNil)
@@ -127,9 +170,15 @@ func TestTagCacheWorks(t *testing.T) {
 			pin, err := tc3.ResolveTag(ctx, "pkg", "tag:1")
 			So(err, ShouldBeNil)
 			So(pin, ShouldResemble, cannedPin)
+			file, err := tc3.ResolveFile(ctx, numberedPin(0), "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, numberedID(0))
 			pin, err = tc3.ResolveTag(ctx, "pkg", "tag:2")
 			So(err, ShouldBeNil)
 			So(pin, ShouldResemble, cannedPin)
+			file, err = tc3.ResolveFile(ctx, numberedPin(1), "filename")
+			So(err, ShouldBeNil)
+			So(file, ShouldEqual, numberedID(1))
 		})
 	})
 }