Method fileMapFromDuplicate

pkg/client/upload.go:514–544

fileMapFromDuplicate queries the server's search interface for an existing file blob for the file contents any of wholeRef. If the server has it, it's validated, and then fileMap (which must already be partially populated) has its "parts" field populated, and then fileMap is uploaded (if necessary).

(ctx context.Context, fileMap *schema.Builder, wholeRef []blob.Ref)

// and then fileMap is uploaded (if necessary).
// If no file blob is found, a zero blob.Ref (and no error) is returned.
func (c *Client) fileMapFromDuplicate(ctx context.Context, fileMap *schema.Builder, wholeRef []blob.Ref) (blob.Ref, error) {
	dupFileRef, err := c.SearchExistingFileSchema(ctx, wholeRef...)
	if err != nil {
		return blob.Ref{}, err
	}
	if !dupFileRef.Valid() {
		// because SearchExistingFileSchema returns blob.Ref{}, nil when file is not found.
		return blob.Ref{}, nil
	}
	dupMap, err := c.FetchSchemaBlob(ctx, dupFileRef)
	if err != nil {
		return blob.Ref{}, fmt.Errorf("could not find existing file blob for wholeRef %q: %v", wholeRef, err)
	}
	fileMap.PopulateParts(dupMap.PartsSize(), dupMap.ByteParts())
	json, err := fileMap.JSON()
	if err != nil {
		return blob.Ref{}, fmt.Errorf("could not write file map for wholeRef %q: %v", wholeRef, err)
	}
	bref := blob.RefFromString(json)
	if bref == dupFileRef {
		// Unchanged (same filename, modtime, JSON serialization, etc)
		// Different signer (e.g. existing file has a sha1 signer, and
		// we're now using a sha224 signer) means we upload a new file schema.
		return dupFileRef, nil
	}
	sbr, err := c.ReceiveBlob(ctx, bref, strings.NewReader(json))
	if err != nil {
		return blob.Ref{}, err
	}
	return sbr.Ref, nil
}