Unexport some externally irrelevant symbols from uploadstore (sourceg…

…raph#63647)

These symbols aren't used outside of the package, so unexporting them
for a cleaner API surface.

Test plan:

Go compiler doesn't complain.

internal/uploadstore/gcs_client.go

@@ -123,7 +123,7 @@ func (s *gcsStore) Get(ctx context.Context, key string) (_ io.ReadCloser, err er
 		return nil, errors.Wrap(err, "failed to get object")
 	}
 
-	return NewExtraCloser(rc, done), nil
+	return newExtraCloser(rc, done), nil
 }
 
 func (s *gcsStore) Upload(ctx context.Context, key string, r io.Reader) (_ int64, err error) {
@@ -229,7 +229,7 @@ func (s *gcsStore) create(ctx context.Context, bucket gcsBucketHandle) error {
 }
 
 func (s *gcsStore) deleteSources(ctx context.Context, bucket gcsBucketHandle, sources []string) error {
-	return ForEachString(sources, func(index int, source string) error {
+	return forEachString(sources, func(index int, source string) error {
 		if err := bucket.Object(source).Delete(ctx); err != nil {
 			return errors.Wrap(err, "failed to delete source object")
 		}

internal/uploadstore/pool.go

@@ -6,12 +6,12 @@ import (
 	"github.com/sourcegraph/conc/pool"
 )
 
-// ForEachString invokes the given callback once for each of the
+// forEachString invokes the given callback once for each of the
 // given string values. The callback function will receive the index as well
 // as the string value as parameters. Callbacks will be invoked in a number
 // of concurrent routines proportional to the maximum number of CPUs that
 // can be executing simultaneously.
-func ForEachString(values []string, f func(index int, value string) error) error {
+func forEachString(values []string, f func(index int, value string) error) error {
 	p := pool.New().
 		WithErrors().
 		WithMaxGoroutines(runtime.GOMAXPROCS(0))

internal/uploadstore/reader.go

@@ -13,8 +13,8 @@ func (c *closeWrapper) Close() error {
 	return nil
 }
 
-// NewExtraCloser returns wraps a ReadCloser with an extra close function
+// newExtraCloser returns wraps a ReadCloser with an extra close function
 // that will be called after the underlying ReadCloser has been closed.
-func NewExtraCloser(rc io.ReadCloser, close func()) io.ReadCloser {
+func newExtraCloser(rc io.ReadCloser, close func()) io.ReadCloser {
 	return &closeWrapper{ReadCloser: rc, close: close}
 }

internal/uploadstore/s3_client.go

@@ -128,7 +128,7 @@ func (s *s3Store) List(ctx context.Context, prefix string) (_ *iterator.Iterator
 }
 
 func (s *s3Store) Get(ctx context.Context, key string) (_ io.ReadCloser, err error) {
-	ctx, _, endObservation := s.operations.Get.With(ctx, &err, observation.Args{Attrs: []attribute.KeyValue{
+	ctx, traceLogger, endObservation := s.operations.Get.With(ctx, &err, observation.Args{Attrs: []attribute.KeyValue{
 		attribute.String("key", key),
 	}})
 	done := func() { endObservation(1, observation.Args{}) }
@@ -144,7 +144,7 @@ func (s *s3Store) Get(ctx context.Context, key string) (_ io.ReadCloser, err err
 			}
 
 			byteOffset += n
-			s.operations.Get.Logger.Warn("Transient error while reading payload", log.String("key", key), log.Error(err))
+			traceLogger.Warn("Transient error while reading payload", log.String("key", key), log.Error(err))
 
 			if n == 0 {
 				zeroReads++
@@ -158,7 +158,7 @@ func (s *s3Store) Get(ctx context.Context, key string) (_ io.ReadCloser, err err
 		}
 	})
 
-	return NewExtraCloser(io.NopCloser(reader), done), nil
+	return newExtraCloser(io.NopCloser(reader), done), nil
 }
 
 // ioCopyHook is a pointer to io.Copy. This function is replaced in unit tests so that we can
@@ -243,7 +243,7 @@ func (s *s3Store) Compose(ctx context.Context, destination string, sources ...st
 	var m sync.Mutex
 	etags := map[int]*string{}
 
-	if err := ForEachString(sources, func(index int, source string) error {
+	if err := forEachString(sources, func(index int, source string) error {
 		partNumber := index + 1
 
 		copyResult, err := s.client.UploadPartCopy(ctx, &s3.UploadPartCopyInput{
@@ -374,7 +374,7 @@ func (s *s3Store) create(ctx context.Context) error {
 }
 
 func (s *s3Store) deleteSources(ctx context.Context, bucket string, sources []string) error {
-	return ForEachString(sources, func(index int, source string) error {
+	return forEachString(sources, func(index int, source string) error {
 		if _, err := s.client.DeleteObject(ctx, &s3.DeleteObjectInput{
 			Bucket: aws.String(bucket),
 			Key:    aws.String(source),