Use generic item in Drive backup (#4357)

Use generic lazy item implementation for drive
backups. This is a bit of a stop-gap
implementation since the drive logic is more
complex than exchange logic

Refactoring the drive logic to streamline it
would help reduce the number of functions
called to download a single item etc.

---

#### Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No

#### Type of change

- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [x] 🧹 Tech Debt/Cleanup

#### Issue(s)

* #4191

#### Test Plan

- [ ] 💪 Manual
- [x] ⚡ Unit test
- [x] 💚 E2E

src/internal/m365/collection/drive/collection.go

@@ -35,9 +35,6 @@ const (
 
 var (
 	_ data.BackupCollection = &Collection{}
-	_ data.Item             = &Item{}
-	_ data.ItemInfo         = &Item{}
-	_ data.ItemModTime      = &Item{}
 	_ data.Item             = &metadata.Item{}
 	_ data.ItemModTime      = &metadata.Item{}
 )
@@ -244,22 +241,6 @@ func (oc Collection) DoNotMergeItems() bool {
 	return oc.doNotMergeItems
 }
 
-// Item represents a single item retrieved from OneDrive
-type Item struct {
-	id   string
-	data io.ReadCloser
-	info details.ItemInfo
-}
-
-// Deleted implements an interface function. However, OneDrive items are marked
-// as deleted by adding them to the exclude list so this can always return
-// false.
-func (i Item) Deleted() bool                    { return false }
-func (i *Item) ID() string                      { return i.id }
-func (i *Item) ToReader() io.ReadCloser         { return i.data }
-func (i *Item) Info() (details.ItemInfo, error) { return i.info, nil }
-func (i *Item) ModTime() time.Time              { return i.info.Modified() }
-
 // getDriveItemContent fetch drive item's contents with retries
 func (oc *Collection) getDriveItemContent(
 	ctx context.Context,
@@ -470,6 +451,54 @@ func (oc *Collection) streamItems(ctx context.Context, errs *fault.Bus) {
 	oc.reportAsCompleted(ctx, int(stats.itemsFound), int(stats.itemsRead), stats.byteCount)
 }
 
+type lazyItemGetter struct {
+	info                 *details.ItemInfo
+	item                 models.DriveItemable
+	driveID              string
+	suffix               string
+	itemExtensionFactory []extensions.CreateItemExtensioner
+	contentGetter        func(
+		ctx context.Context,
+		driveID string,
+		item models.DriveItemable,
+		errs *fault.Bus) (io.ReadCloser, error)
+}
+
+func (lig *lazyItemGetter) GetData(
+	ctx context.Context,
+	errs *fault.Bus,
+) (io.ReadCloser, *details.ItemInfo, bool, error) {
+	rc, err := lig.contentGetter(ctx, lig.driveID, lig.item, errs)
+	if err != nil {
+		return nil, nil, false, clues.Stack(err)
+	}
+
+	extRc, extData, err := extensions.AddItemExtensions(
+		ctx,
+		rc,
+		*lig.info,
+		lig.itemExtensionFactory)
+	if err != nil {
+		err := clues.Wrap(err, "adding extensions").
+			WithClues(ctx).
+			Label(fault.LabelForceNoBackupCreation)
+
+		return nil, nil, false, err
+	}
+
+	lig.info.Extension.Data = extData.Data
+
+	// display/log the item download
+	progReader, _ := observe.ItemProgress(
+		ctx,
+		extRc,
+		observe.ItemBackupMsg,
+		clues.Hide(ptr.Val(lig.item.GetName())+lig.suffix),
+		ptr.Val(lig.item.GetSize()))
+
+	return progReader, lig.info, false, nil
+}
+
 func (oc *Collection) streamDriveItem(
 	ctx context.Context,
 	parentPath *path.Builder,
@@ -530,45 +559,23 @@ func (oc *Collection) streamDriveItem(
 	if isFile {
 		dataSuffix := metadata.DataFileSuffix
 
-		// Construct a new lazy readCloser to feed to the collection consumer.
+		// Use a LazyItem to feed to the collection consumer.
 		// This ensures that downloads won't be attempted unless that consumer
 		// attempts to read bytes.  Assumption is that kopia will check things
 		// like file modtimes before attempting to read.
-		itemReader := lazy.NewLazyReadCloser(func() (io.ReadCloser, error) {
-			rc, err := oc.getDriveItemContent(ctx, oc.driveID, item, errs)
-			if err != nil {
-				return nil, err
-			}
-
-			extRc, extData, err := extensions.AddItemExtensions(
+		oc.data <- data.NewLazyItem(
 			ctx,
-				rc,
-				itemInfo,
-				itemExtensionFactory)
-			if err != nil {
-				err := clues.Wrap(err, "adding extensions").Label(fault.LabelForceNoBackupCreation)
-				errs.AddRecoverable(ctx, err)
-				return nil, err
-			}
-
-			itemInfo.Extension.Data = extData.Data
-
-			// display/log the item download
-			progReader, _ := observe.ItemProgress(
-				ctx,
-				extRc,
-				observe.ItemBackupMsg,
-				clues.Hide(itemName+dataSuffix),
-				itemSize)
-
-			return progReader, nil
-		})
-
-		oc.data <- &Item{
-			id:   itemID + dataSuffix,
-			data: itemReader,
-			info: itemInfo,
-		}
+			&lazyItemGetter{
+				info:                 &itemInfo,
+				item:                 item,
+				driveID:              oc.driveID,
+				itemExtensionFactory: itemExtensionFactory,
+				contentGetter:        oc.getDriveItemContent,
+				suffix:               dataSuffix,
+			},
+			itemID+dataSuffix,
+			itemInfo.Modified(),
+			errs)
 	}
 
 	metaReader := lazy.NewLazyReadCloser(func() (io.ReadCloser, error) {

src/internal/m365/collection/drive/collection_test.go

@@ -981,15 +981,17 @@ func (suite *CollectionUnitSuite) TestItemExtensions() {
 			ei, ok := collItem.(data.ItemInfo)
 			assert.True(t, ok)
 
-			itemInfo, err := ei.Info()
-			require.NoError(t, err, clues.ToCore(err))
+			r := collItem.ToReader()
 
-			_, err = io.ReadAll(collItem.ToReader())
+			_, err = io.ReadAll(r)
 			test.expectReadErr(t, err, clues.ToCore(err))
 
-			err = collItem.ToReader().Close()
+			err = r.Close()
 			test.expectCloseErr(t, err, clues.ToCore(err))
 
+			itemInfo, err := ei.Info()
+			require.NoError(t, err, clues.ToCore(err))
+
 			// Verify extension data
 			test.expect(t, itemInfo, test.payload)
 		})

src/internal/m365/helper_test.go

@@ -17,7 +17,6 @@ import (
 
 	"github.com/alcionai/corso/src/internal/common/ptr"
 	"github.com/alcionai/corso/src/internal/data"
-	"github.com/alcionai/corso/src/internal/m365/collection/drive"
 	"github.com/alcionai/corso/src/internal/m365/collection/drive/metadata"
 	odStub "github.com/alcionai/corso/src/internal/m365/service/onedrive/stub"
 	m365Stub "github.com/alcionai/corso/src/internal/m365/stub"
@@ -731,7 +730,7 @@ func compareDriveItem(
 	)
 
 	if !isMeta {
-		oitem := item.(*drive.Item)
+		oitem := item.(data.ItemInfo)
 
 		info, err := oitem.Info()
 		if !assert.NoError(t, err, clues.ToCore(err)) {