parse the DCF structure under DCIM (closes #2)

A card is now read by the naming rules in CIPA DC-009-2010, not by
looking for media extensions anywhere on the volume.

Store.Directories holds the DCF directories and their objects, with
directory and file numbers. Store.NonConforming lists everything else
under DCIM, including symlinks and names fs.FS refuses. Media under
PRIVATE/M4ROOT stays, with no DCF numbers. Media anywhere else is no
longer part of the store. A symlink is never followed, and a read error
names the card's mount point.

Model: opus-5-5

README.md

@@ -3,7 +3,7 @@
 ## Description
 
 `dcf` is a WTFPL-licensed Go library by [@sneak](https://sneak.berlin) that
-reads DCF memory cards from digital cameras and copies the files off them.
+reads DCF memory cards from digital cameras.
 
 DCF is the "Design rule for Camera File system". It is also JEITA specification
 number CP-3461. JEITA is the Japan Electronics and Information Technology
@@ -29,7 +29,6 @@ Then list the DCF stores on the mounted filesystems:
 package main
 
 import (
-	"context"
 	"fmt"
 	"log"
 
@@ -37,53 +36,17 @@ import (
 )
 
 func main() {
-	stores, err := dcf.GetStores(context.Background())
+	stores, err := dcf.GetDCFStores(0)
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	for _, store := range stores {
+	for _, store := range *stores {
 		fmt.Println(store.String())
 	}
 }
 ```
 
-Call `dcf.GetStore` instead when you expect exactly one DCF store. It returns
-`dcf.ErrNoStore` when none is mounted, and `dcf.ErrMultipleStores` when more
-than one is.
-
-To copy the files off a card, call `Import` with a destination directory:
-
-```go
-package main
-
-import (
-	"context"
-	"fmt"
-	"log"
-
-	"sneak.berlin/go/dcf/pkg/dcf"
-)
-
-func main() {
-	ctx := context.Background()
-
-	store, err := dcf.GetStore(ctx)
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	result, err := store.Import(ctx, "/path/to/photos")
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	fmt.Println("copied:", result.Copied)
-	fmt.Println("skipped:", result.Skipped)
-	fmt.Println("conflicts:", result.Conflicts)
-}
-```
-
 To work on the library itself, you need docker and git:
 
 ```sh
@@ -142,28 +105,21 @@ overengineering and reusable code.
 
 All the code is in the `pkg/dcf` package. The repo has no commands.
 
-- `dcf.go` holds the public API for reading a card. `GetStores` finds the DCF
+- `dcf.go` holds the public API. `GetDCFStores` finds the DCF stores and reads
-  stores and reads each one. `GetStore` returns the one DCF store when exactly
+  each one.
-  one is mounted.
 - `helpers.go` finds the mount points that hold a DCF store.
 - `parse.go` reads one DCF store through an `fs.FS` rooted at its mount point.
-- `filegroup.go` sorts the files of one DCF directory into file groups.
-- `import.go` holds `Store.Import`, which copies files off a card.
 
 The main types are:
 
 - `Store` is one DCF store on one mounted filesystem.
-- `Directory` is one DCF directory. It has a directory number, a name, the
+- `Directory` is one DCF directory. It has a directory number, a name and the
-  objects inside it and their file groups.
+  objects inside it.
 - `Object` is one file in a store. A file in a DCF directory also has a
-  directory number and a file number. `Object.ModTime` is its modification time.
+  directory number and a file number.
-  `Object.Hash` reads the file through the `fs.FS` of its store. An `Object` you
-  build yourself has none, so its `Hash` returns an error.
-- `FileGroup` is one file group in a DCF directory.
 - `Image` and `Video` embed `Object`. The file extension decides which one a
   file becomes. A file with any other extension, such as a `THM` thumbnail, is
   neither.
-- `ImportResult` lists what `Store.Import` did with each file.
 
 A mounted filesystem is a DCF store when its root holds a `DCIM` or
 `PRIVATE/M4ROOT` directory. It needs only one of them. `dcf` never mounts a
@@ -171,10 +127,6 @@ filesystem. Media anywhere else on the filesystem is not part of the store.
 
 `dcf` never follows a symlink.
 
-`GetStores` and `GetStore` take a `context.Context`. When it is cancelled, the
-read stops before the next directory. The returned error matches
-`context.Canceled`.
-
 `dcf` applies the naming rules of the DCF specification, CIPA DC-009-2010, under
 `DCIM`:
 
@@ -197,78 +149,14 @@ The naming rules do not apply under `PRIVATE/M4ROOT`. The images and videos
 there are in `Store.Images` and `Store.Videos`, and their DCF numbers are 0.
 `dcf` skips any symlink there.
 
-A file group is made of the DCF files in one DCF directory that share a file
-number. The specification calls it a DCF object. A RAW file and its JPEG form a
-file group, and so do a video and its `THM` thumbnail.
-
-- The first four characters and the extension can differ within a group.
-- A DCF file that shares its number with no other file is a group of one.
-- Files in different DCF directories are never in the same group.
-- Only DCF files are grouped. Files in `Store.NonConforming` and under
-  `PRIVATE/M4ROOT` are in no group.
-
-`Directory.FileGroups` lists the groups in file number order. Each `FileGroup`
-has:
-
-- `DirectoryNumber` and `FileNumber`
-- `Members`, which is every file in the group
-- `Primary`, which is the member that stands for the whole group
-- `MembersCount`, which returns the number of members
-- `TotalSize`, which returns the total size of the members in bytes
-
-The primary member is the first of these that the group holds:
-
-1. a `JPG` file
-2. any other file in `Store.Images`
-3. a file in `Store.Videos`
-4. any other file except a `THM`
-5. a `THM`
-
-`Store.Images` and `Store.Videos` list each file on its own, whatever its group.
-
-`Store.Import` copies files off a card to a destination directory. It verifies
-each copy against the SHA256 hash of its source. It only reads the card, so it
-never deletes anything there.
-
-It copies:
-
-- every member of every file group
-- the images and videos under `PRIVATE/M4ROOT`
-
-It does not copy the files in `Store.NonConforming`.
-
-Each file goes to `YYYY-MM-DD/<file name>` under the destination directory. The
-date is the day of the file's modification time, in the computer's time zone.
-Every member of a file group goes to the day of its primary member, so a group
-never splits across two folders. Each copy keeps the modification time of its
-source. Only the user who ran the import can read the copies.
-
-`ImportResult` lists each destination path in one of three lists:
-
-- `Copied` holds the copies this import wrote and verified.
-- `Skipped` holds the paths that already held a file with the same SHA256 hash.
-- `Conflicts` holds the paths that already held anything else. `dcf` leaves that
-  alone and does not copy the file.
-
-A conflict is not an error, so a caller must check `Conflicts`. These are the
-usual causes:
-
-- Two different files have the same name and the same day. Two cards can reuse a
-  file number, and so can two DCF directories on one card. The first file is
-  copied, and the second is a conflict.
-- A partial file remains because the process died during a copy. Delete it and
-  import again.
-
-A copy that fails or does not match the hash of its source is removed. One file
-that fails does not stop the others. The returned error joins the failures, each
-naming its file. The result still lists what was done.
-
-When the context is cancelled, the import stops at once, even inside a file, and
-removes the partial copy. The returned error matches `context.Canceled`.
-
 ## TODO
 
-No open items.
+- Handle DCF file groups, where multiple objects share the same index number.
+  `dcf` does not handle these yet. If you need this, send me a link to a zip or
+  tar of a memory card that uses them, and I'll see what I can do.
+- Take a `context.Context` to cancel the walk of a store.
+- Return a plain slice from `GetDCFStores`, not a pointer to one.
+- Copy files off a card, and verify each copy against its SHA256 hash.
 
 ## License
 

pkg/dcf/dcf.go

@@ -2,33 +2,22 @@
 // Camera File system" specification (JEITA CP-3461). It finds the cards among
 // the mounted filesystems and parses the DCF directories and files on each one
 // into their directory numbers and file numbers. It lists the images and videos
-// on each card, and everything under DCIM that is not a DCF directory or file. It
+// on each card, and everything under DCIM that is not a DCF directory or file.
-// groups the files in each DCF directory that share a file number. It copies the
-// files off a card, and verifies each copy against its SHA256 hash.
 package dcf
 
 import (
-	"context"
+	"crypto/sha256"
-	"errors"
+	"encoding/hex"
 	"fmt"
-	"io/fs"
+	"io"
 	"os"
 	"path/filepath"
 	"slices"
 	"strings"
-	"time"
 
 	"github.com/dustin/go-humanize"
 )
 
-var (
-	// ErrNoStore is the error from GetStore when no DCF store is mounted.
-	ErrNoStore = errors.New("no DCF store is mounted")
-	// ErrMultipleStores is the error from GetStore when more than one DCF store
-	// is mounted.
-	ErrMultipleStores = errors.New("more than one DCF store is mounted")
-)
-
 // Store represents a DCF store, which is a directory structure that contains
 // images and videos in the root of a mounted filesystem.
 type Store struct {
@@ -57,22 +46,6 @@ type Directory struct {
 	// Objects holds every DCF file in the directory, including those that are
 	// neither images nor videos.
 	Objects []*Object
-	// FileGroups holds the same files, grouped by file number, in file number
-	// order.
-	FileGroups []*FileGroup
-}
-
-// FileGroup represents one file group: the files in one DCF directory that share
-// a file number. The DCF specification calls this a DCF object. A file that
-// shares its number with no other file is a group of one.
-type FileGroup struct {
-	DirectoryNumber int
-	FileNumber      int
-	// Members holds every file in the group, including Primary, in name order.
-	// Two members can have the same extension.
-	Members []*Object
-	// Primary is the member that stands for the whole group.
-	Primary *Object
 }
 
 // Object represents a file in a DCF store. It is embedded in Image and Video
@@ -82,15 +55,10 @@ type Object struct {
 	Path         string
 	Size         int64
 	Extension    string
-	// ModTime is the modification time of the file.
-	ModTime time.Time
 	// DirectoryNumber and FileNumber are the DCF numbers of a file in a DCF
 	// directory. Both are 0 for a file under PRIVATE/M4ROOT.
 	DirectoryNumber int
 	FileNumber      int
-	// fsys is the fs.FS the store was read through. Hash reads the file through
-	// it.
-	fsys fs.FS
 }
 
 // Image represents an image file on a DCF store.
@@ -146,21 +114,6 @@ func (d *Store) TotalSize() int64 {
 	return d.TotalImageSize() + d.TotalVideoSize()
 }
 
-// MembersCount returns the number of files in the file group.
-func (g *FileGroup) MembersCount() int {
-	return len(g.Members)
-}
-
-// TotalSize returns the total size in bytes of the files in the file group.
-func (g *FileGroup) TotalSize() int64 {
-	totalSize := int64(0)
-	for _, member := range g.Members {
-		totalSize += member.Size
-	}
-
-	return totalSize
-}
-
 func (d *Store) String() string {
 	// A caller can set a negative Size, and uint64 would make that huge.
 	totalSize := uint64(max(d.TotalSize(), 0))
@@ -188,80 +141,61 @@ func (i *Image) String() string {
 	)
 }
 
-// Hash returns the SHA256 hash of the file as a hex string. It reads the file
+// Hash returns the SHA256 hash of the file as a hex string.
-// through the fs.FS of its store. An Object built by hand has none, so Hash
-// returns an error that matches fs.ErrInvalid.
 func (d *Object) Hash() (string, error) {
-	hash, err := d.hash(context.Background())
+	return pathToSHA256(d.FullFilePath())
+}
+
+func pathToSHA256(path string) (string, error) {
+	file, err := os.Open(filepath.Clean(path))
 	if err != nil {
-		return "", fmt.Errorf("hashing %s: %w", d.FullFilePath(), err)
+		return "", err
 	}
 
-	return hash, nil
+	defer func() { _ = file.Close() }()
-}
 
-// hash returns the SHA256 hash of the file as a hex string, and stops when ctx is
+	hash := sha256.New()
-// cancelled.
+
-func (d *Object) hash(ctx context.Context) (string, error) {
+	_, err = io.Copy(hash, file)
-	if d.fsys == nil {
+	if err != nil {
-		return "", fs.ErrInvalid
+		return "", err
 	}
 
-	return hashFile(ctx, d.fsys, d.Path)
+	return hex.EncodeToString(hash.Sum(nil)), nil
 }
 
-// GetStores finds the DCF stores in the root of the mounted filesystems and reads
+// GetDCFStores returns a list of DCF stores found on the system in the root of
-// each one. It does not mount filesystems or search outside of filesystem root
+// any mounted filesystems. The integer argument is the number of DCF stores to
-// directories. It reads the DCIM and PRIVATE/M4ROOT directories of each
+// return. If the argument is 0, all DCF stores are returned. It does not mount
-// filesystem to populate the returned Stores. It never follows a symlink. If a
+// filesystems or search outside of filesystem root directories. It does,
-// card cannot be read, it returns an error that names the card's mount point.
+// however, read the DCIM and PRIVATE/M4ROOT directories of each filesystem to
-// When ctx is cancelled, the read stops before the next directory, and the error
+// populate the returned Stores. It never follows a symlink. If a card cannot be
-// matches ctx.Err().
+// read, it returns an error that names the card's mount point.
-func GetStores(ctx context.Context) ([]*Store, error) {
+func GetDCFStores(requestedCount int) (*[]Store, error) {
-	dcfStorePaths, err := findDCFMountPoints(ctx)
+	dcfStorePaths, err := findDCFMountPoints(requestedCount)
 	if err != nil {
 		return nil, err
 	}
 
-	return parseStores(ctx, dcfStorePaths)
+	dcfStores, err := parseStores(dcfStorePaths)
-}
-
-// GetStore returns the one DCF store when exactly one is mounted. It returns
-// ErrNoStore when none is mounted, and ErrMultipleStores when more than one is.
-// It reads every card first, the way GetStores does, so a card that cannot be
-// read returns that error instead.
-func GetStore(ctx context.Context) (*Store, error) {
-	stores, err := GetStores(ctx)
 	if err != nil {
 		return nil, err
 	}
 
-	return onlyStore(stores)
+	return &dcfStores, nil
-}
-
-// onlyStore returns the store when stores holds exactly one.
-func onlyStore(stores []*Store) (*Store, error) {
-	switch len(stores) {
-	case 0:
-		return nil, ErrNoStore
-	case 1:
-		return stores[0], nil
-	default:
-		return nil, ErrMultipleStores
-	}
 }
 
 // parseStores reads the card at each of the given mount points.
-func parseStores(ctx context.Context, mountpoints []string) ([]*Store, error) {
+func parseStores(mountpoints []string) ([]Store, error) {
-	dcfStores := []*Store{}
+	dcfStores := []Store{}
 
 	for _, mountpoint := range mountpoints {
-		dcfStore, err := parseStore(ctx, os.DirFS(mountpoint), mountpoint)
+		dcfStore, err := parseStore(os.DirFS(mountpoint), mountpoint)
 		if err != nil {
 			return nil, err
 		}
 
-		dcfStores = append(dcfStores, dcfStore)
+		dcfStores = append(dcfStores, *dcfStore)
 	}
 
 	return dcfStores, nil
@@ -269,7 +203,7 @@ func parseStores(ctx context.Context, mountpoints []string) ([]*Store, error) {
 
 func isImageFile(path string) bool {
 	imageExtensions := []string{
-		".jpg", ".jpeg", ".png", ".gif", ".bmp", ".tif", ".tiff", ".raw", ".arw",
+		".jpg", ".jpeg", ".png", ".gif", ".bmp", ".tiff", ".raw", ".arw",
 	}
 
 	return slices.Contains(imageExtensions, strings.ToLower(filepath.Ext(path)))

pkg/dcf/dcf_internal_test.go

@@ -1,13 +1,9 @@
 package dcf
 
 import (
-	"context"
-	"errors"
-	"io/fs"
 	"path/filepath"
 	"strings"
 	"testing"
-	"testing/fstest"
 )
 
 func TestParseStoresReadsEachMountPoint(t *testing.T) {
@@ -16,7 +12,7 @@ func TestParseStoresReadsEachMountPoint(t *testing.T) {
 	first := newCardOnDisk(t, "DCIM/100ABCDE/ABCD0001.JPG")
 	second := newCardOnDisk(t, "PRIVATE/M4ROOT/CLIP/C0001.MP4")
 
-	stores, err := parseStores(t.Context(), []string{first, second})
+	stores, err := parseStores([]string{first, second})
 	if err != nil {
 		t.Fatalf("parseStores: %v", err)
 	}
@@ -54,100 +50,18 @@ func TestParseStoresReturnsErrorNamingTheCard(t *testing.T) {
 	// Every lookup under a plain file fails.
 	mountpoint := filepath.Join(newCardOnDisk(t, "FILE"), "FILE")
 
-	_, err := parseStores(t.Context(), []string{mountpoint})
+	_, err := parseStores([]string{mountpoint})
 	if err == nil || !strings.Contains(err.Error(), mountpoint) {
 		t.Fatalf("parseStores error = %v, want one naming %s", err, mountpoint)
 	}
 }
 
-func TestParseStoresReturnsErrorWhenCancelled(t *testing.T) {
-	t.Parallel()
-
-	ctx, cancel := context.WithCancel(t.Context())
-	cancel()
-
-	mountpoint := newCardOnDisk(t, "DCIM/100ABCDE/ABCD0001.JPG")
-
-	_, err := parseStores(ctx, []string{mountpoint})
-	if !errors.Is(err, context.Canceled) {
-		t.Fatalf("parseStores error = %v, want %v", err, context.Canceled)
-	}
-}
-
-func TestOnlyStore(t *testing.T) {
-	t.Parallel()
-
-	first := newMountPoint(t, dcimDirectory)
-	second := newMountPoint(t, m4RootDirectory)
-
-	stores, err := parseStores(t.Context(), []string{first, second})
-	if err != nil {
-		t.Fatalf("parseStores: %v", err)
-	}
-
-	_, err = onlyStore(stores[:0])
-	if !errors.Is(err, ErrNoStore) {
-		t.Errorf("onlyStore of no cards: error = %v, want %v", err, ErrNoStore)
-	}
-
-	store, err := onlyStore(stores[:1])
-	if err != nil {
-		t.Fatalf("onlyStore of one card: %v", err)
-	}
-
-	if store.RootDirectory != first {
-		t.Errorf("onlyStore returned the card at %s, want %s",
-			store.RootDirectory, first)
-	}
-
-	_, err = onlyStore(stores)
-	if !errors.Is(err, ErrMultipleStores) {
-		t.Errorf("onlyStore of two cards: error = %v, want %v",
-			err, ErrMultipleStores)
-	}
-}
-
-func TestObjectHashReadsThroughTheCard(t *testing.T) {
-	t.Parallel()
-
-	card := fstest.MapFS{"DCIM/100ABCDE/ABCD0001.JPG": {Data: []byte("abc")}}
-
-	got, err := mustParseStore(t, card).Images[0].Hash()
-	if err != nil {
-		t.Fatalf("Hash() returned error: %v", err)
-	}
-
-	// The published SHA-256 test vector for "abc".
-	want := "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad"
-	if got != want {
-		t.Fatalf("Hash() = %q, want %q", got, want)
-	}
-}
-
-func TestObjectHashOfMissingFileReturnsError(t *testing.T) {
-	t.Parallel()
-
-	const filePath = "DCIM/100ABCDE/ABCD0001.JPG"
-
-	card := newCard(filePath)
-	image := mustParseStore(t, card).Images[0]
-
-	delete(card, filePath)
-
-	_, err := image.Hash()
-	if !errors.Is(err, fs.ErrNotExist) {
-		t.Fatalf("Hash() error = %v, want %v", err, fs.ErrNotExist)
-	}
-}
-
 func TestIsImageFile(t *testing.T) {
 	t.Parallel()
 
 	cases := map[string]bool{
 		"DCIM/100MSDCF/DSC00001.jpg":    true,
 		"DCIM/100MSDCF/DSC00001.ARW":    true,
-		"DCIM/100MSDCF/DSC00001.TIF":    true,
-		"DCIM/100MSDCF/DSC00001.tif":    true,
 		"PRIVATE/M4ROOT/CLIP/C0001.MP4": false,
 		"DCIM/100MSDCF/notes.txt":       false,
 		"DCIM/100MSDCF/noextension":     false,

pkg/dcf/dcf_test.go

@@ -1,9 +1,8 @@
 package dcf_test
 
 import (
-	"context"
+	"os"
-	"errors"
+	"path/filepath"
-	"io/fs"
 	"testing"
 
 	"sneak.berlin/go/dcf/pkg/dcf"
@@ -126,30 +125,37 @@ func TestVideoString(t *testing.T) {
 	}
 }
 
-func TestObjectHashOfObjectBuiltByHandReturnsError(t *testing.T) {
+func TestObjectHashIsSHA256OfFile(t *testing.T) {
 	t.Parallel()
 
-	object := dcf.Object{DCFStoreRoot: cardRoot, Path: "a.jpg"}
+	root := t.TempDir()
+
+	err := os.WriteFile(filepath.Join(root, "a.jpg"), []byte("abc"), 0o600)
+	if err != nil {
+		t.Fatalf("WriteFile: %v", err)
+	}
+
+	object := dcf.Object{DCFStoreRoot: root, Path: "a.jpg"}
+
+	got, err := object.Hash()
+	if err != nil {
+		t.Fatalf("Hash() returned error: %v", err)
+	}
+
+	// The published SHA-256 test vector for "abc".
+	want := "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad"
+	if got != want {
+		t.Fatalf("Hash() = %q, want %q", got, want)
+	}
+}
+
+func TestObjectHashOfMissingFileReturnsError(t *testing.T) {
+	t.Parallel()
+
+	object := dcf.Object{DCFStoreRoot: t.TempDir(), Path: "absent.jpg"}
 
 	_, err := object.Hash()
-	if !errors.Is(err, fs.ErrInvalid) {
+	if err == nil {
-		t.Fatalf("Hash() error = %v, want %v", err, fs.ErrInvalid)
+		t.Fatal("Hash() of a missing file returned no error")
-	}
-}
-
-func TestGetStoresAndGetStoreReturnCancellation(t *testing.T) {
-	t.Parallel()
-
-	ctx, cancel := context.WithCancel(t.Context())
-	cancel()
-
-	_, err := dcf.GetStores(ctx)
-	if !errors.Is(err, context.Canceled) {
-		t.Errorf("GetStores error = %v, want %v", err, context.Canceled)
-	}
-
-	_, err = dcf.GetStore(ctx)
-	if !errors.Is(err, context.Canceled) {
-		t.Errorf("GetStore error = %v, want %v", err, context.Canceled)
 	}
 }

pkg/dcf/filegroup.go

@@ -1,67 +0,0 @@
-package dcf
-
-import (
-	"cmp"
-	"path"
-	"slices"
-	"strings"
-)
-
-// newFileGroups sorts the objects of one DCF directory into file groups, in file
-// number order. Section 4.3.2.2 of the specification says the files in a DCF
-// directory that share a file number are one group. Their first four characters
-// and their extensions can differ.
-func newFileGroups(objects []*Object) []*FileGroup {
-	var groups []*FileGroup
-
-	groupWithNumber := map[int]*FileGroup{}
-
-	for _, object := range objects {
-		group, found := groupWithNumber[object.FileNumber]
-		if !found {
-			group = &FileGroup{
-				DirectoryNumber: object.DirectoryNumber,
-				FileNumber:      object.FileNumber,
-			}
-			groupWithNumber[object.FileNumber] = group
-			groups = append(groups, group)
-		}
-
-		group.Members = append(group.Members, object)
-	}
-
-	for _, group := range groups {
-		group.Primary = primaryMember(group.Members)
-	}
-
-	slices.SortFunc(groups, func(a, b *FileGroup) int {
-		return cmp.Compare(a.FileNumber, b.FileNumber)
-	})
-
-	return groups
-}
-
-// primaryMember returns the member that stands for the whole group. Section
-// 6.2.1.3 of the specification gives a DCF basic file priority over a DCF extended
-// image file. It says nothing about a DCF optional file, the other kind of JPG, so
-// ranking every JPG first is a choice. Section 4.6 makes a THM only the thumbnail
-// of another file, so it comes last. The specification leaves the rest open, so an
-// image comes before a video, and a video before any other file. Among equals, the
-// first in name order wins.
-func primaryMember(members []*Object) *Object {
-	choices := []func(string) bool{isJPG, isImageFile, isVideoFile, isNotTHM}
-
-	for _, choice := range choices {
-		for _, member := range members {
-			if choice(member.Path) {
-				return member
-			}
-		}
-	}
-
-	return members[0]
-}
-
-func isNotTHM(name string) bool {
-	return !strings.EqualFold(path.Ext(name), ".THM")
-}

pkg/dcf/filegroup_internal_test.go

@@ -1,232 +0,0 @@
-package dcf
-
-import (
-	"slices"
-	"testing"
-	"testing/fstest"
-)
-
-// mustFileGroups returns the file groups of directory, and stops the test unless
-// there are exactly count of them.
-func mustFileGroups(t *testing.T, directory *Directory, count int) []*FileGroup {
-	t.Helper()
-
-	if len(directory.FileGroups) != count {
-		t.Fatalf("%s has %d file groups, want %d",
-			directory.Name, len(directory.FileGroups), count)
-	}
-
-	return directory.FileGroups
-}
-
-// assertFileGroup checks the numbers, the primary member and the members of group.
-func assertFileGroup(
-	t *testing.T,
-	group *FileGroup,
-	directoryNumber, fileNumber int,
-	primary string,
-	members ...string,
-) {
-	t.Helper()
-
-	if group.DirectoryNumber != directoryNumber || group.FileNumber != fileNumber {
-		t.Errorf("group numbers = %d and %d, want %d and %d",
-			group.DirectoryNumber, group.FileNumber, directoryNumber, fileNumber)
-	}
-
-	if group.Primary.Path != primary {
-		t.Errorf("Primary = %q, want %q", group.Primary.Path, primary)
-	}
-
-	paths := make([]string, 0, len(group.Members))
-
-	for _, member := range group.Members {
-		paths = append(paths, member.Path)
-	}
-
-	assertPaths(t, "members", paths, members...)
-
-	if got := group.MembersCount(); got != len(members) {
-		t.Errorf("MembersCount() = %d, want %d", got, len(members))
-	}
-}
-
-// assertSizes checks the total size of group and the size of each member.
-func assertSizes(t *testing.T, group *FileGroup, total int64, sizes ...int64) {
-	t.Helper()
-
-	if got := group.TotalSize(); got != total {
-		t.Errorf("TotalSize() = %d, want %d", got, total)
-	}
-
-	got := make([]int64, 0, len(group.Members))
-
-	for _, member := range group.Members {
-		got = append(got, member.Size)
-	}
-
-	if !slices.Equal(got, sizes) {
-		t.Errorf("member sizes = %v, want %v", got, sizes)
-	}
-}
-
-// assertPrimaryMember checks which of the named members primaryMember picks.
-func assertPrimaryMember(t *testing.T, want string, names ...string) {
-	t.Helper()
-
-	members := make([]*Object, 0, len(names))
-
-	for _, name := range names {
-		members = append(members, &Object{Path: name})
-	}
-
-	if got := primaryMember(members).Path; got != want {
-		t.Errorf("primaryMember of %q = %q, want %q", names, got, want)
-	}
-}
-
-func TestParseStoreGroupsFilesSharingAFileNumber(t *testing.T) {
-	t.Parallel()
-
-	store := mustParseStore(t, fstest.MapFS{
-		"DCIM/100ABCDE/DSC00001.ARW": {Data: make([]byte, 2000)},
-		"DCIM/100ABCDE/DSC00001.JPG": {Data: make([]byte, 500)},
-		"DCIM/100ABCDE/MVI_0002.MP4": {Data: make([]byte, 9000)},
-		"DCIM/100ABCDE/MVI_0002.THM": {Data: make([]byte, 100)},
-		"DCIM/100ABCDE/DSC00003.JPG": {Data: make([]byte, 700)},
-		"DCIM/101ABCDE/DSC00001.JPG": {Data: make([]byte, 300)},
-	})
-
-	first := mustFileGroups(t, store.Directories[0], 3)
-	second := mustFileGroups(t, store.Directories[1], 1)
-
-	assertFileGroup(t, first[0], 100, 1, "DCIM/100ABCDE/DSC00001.JPG",
-		"DCIM/100ABCDE/DSC00001.ARW",
-		"DCIM/100ABCDE/DSC00001.JPG",
-	)
-	assertSizes(t, first[0], 2500, 2000, 500)
-
-	assertFileGroup(t, first[1], 100, 2, "DCIM/100ABCDE/MVI_0002.MP4",
-		"DCIM/100ABCDE/MVI_0002.MP4",
-		"DCIM/100ABCDE/MVI_0002.THM",
-	)
-	assertSizes(t, first[1], 9100, 9000, 100)
-
-	assertFileGroup(t, first[2], 100, 3, "DCIM/100ABCDE/DSC00003.JPG",
-		"DCIM/100ABCDE/DSC00003.JPG",
-	)
-	assertSizes(t, first[2], 700, 700)
-
-	assertFileGroup(t, second[0], 101, 1, "DCIM/101ABCDE/DSC00001.JPG",
-		"DCIM/101ABCDE/DSC00001.JPG",
-	)
-	assertSizes(t, second[0], 300, 300)
-
-	// The images, the videos and the totals still count each file on its own.
-	if got := store.ImagesCount(); got != 4 {
-		t.Errorf("ImagesCount() = %d, want 4", got)
-	}
-
-	if got := store.VideosCount(); got != 1 {
-		t.Errorf("VideosCount() = %d, want 1", got)
-	}
-
-	if got := store.TotalSize(); got != 12500 {
-		t.Errorf("TotalSize() = %d, want 12500", got)
-	}
-}
-
-func TestParseStoreGroupsFilesWhoseFirstFourCharactersDiffer(t *testing.T) {
-	t.Parallel()
-
-	store := mustParseStore(t, newCard(
-		"DCIM/100ABCDE/ABCD0004.TIF",
-		"DCIM/100ABCDE/THMB0004.THM",
-	))
-
-	groups := mustFileGroups(t, store.Directories[0], 1)
-
-	assertFileGroup(t, groups[0], 100, 4, "DCIM/100ABCDE/ABCD0004.TIF",
-		"DCIM/100ABCDE/ABCD0004.TIF",
-		"DCIM/100ABCDE/THMB0004.THM",
-	)
-}
-
-func TestParseStoreOrdersFileGroupsByFileNumber(t *testing.T) {
-	t.Parallel()
-
-	store := mustParseStore(t, newCard(
-		"DCIM/100ABCDE/ABCD0002.JPG",
-		"DCIM/100ABCDE/WXYZ0001.JPG",
-	))
-
-	groups := mustFileGroups(t, store.Directories[0], 2)
-
-	assertFileGroup(t, groups[0], 100, 1, "DCIM/100ABCDE/WXYZ0001.JPG",
-		"DCIM/100ABCDE/WXYZ0001.JPG",
-	)
-	assertFileGroup(t, groups[1], 100, 2, "DCIM/100ABCDE/ABCD0002.JPG",
-		"DCIM/100ABCDE/ABCD0002.JPG",
-	)
-}
-
-func TestParseStoreLeavesOtherFilesOutOfFileGroups(t *testing.T) {
-	t.Parallel()
-
-	store := mustParseStore(t, newCard(
-		"DCIM/100ABCDE/ABCD0004.ARW",
-		"DCIM/100ABCDE/ABCD0004.JPG",
-		"DCIM/100ABCDE/PQRS0004.JPG",
-		"DCIM/100ABCDE/README.TXT",
-		"DCIM/MISC/ABCD0005.JPG",
-		"PRIVATE/M4ROOT/CLIP/C0006.MP4",
-	))
-
-	if len(store.Directories) != 1 {
-		t.Fatalf("got %d directories, want 1", len(store.Directories))
-	}
-
-	groups := mustFileGroups(t, store.Directories[0], 1)
-
-	assertFileGroup(t, groups[0], 100, 4, "DCIM/100ABCDE/ABCD0004.ARW",
-		"DCIM/100ABCDE/ABCD0004.ARW",
-	)
-}
-
-func TestParseStoreGivesDirectoryWithoutDCFFilesNoFileGroups(t *testing.T) {
-	t.Parallel()
-
-	store := mustParseStore(t, newCard("DCIM/100ABCDE/README.TXT"))
-
-	mustFileGroups(t, store.Directories[0], 0)
-}
-
-func TestPrimaryMember(t *testing.T) {
-	t.Parallel()
-
-	// A JPG comes first, in either case.
-	assertPrimaryMember(t, "A0010001.JPG", "A0010001.ARW", "A0010001.JPG")
-	assertPrimaryMember(t, "A0010001.JPG", "A0010001.JPG", "A0010001.MOV")
-	assertPrimaryMember(t, "a0010001.jpg", "a0010001.arw", "a0010001.jpg")
-
-	// Then any other image.
-	assertPrimaryMember(t, "Z0010001.ARW", "A0010001.MP4", "Z0010001.ARW")
-	assertPrimaryMember(t, "Z0010001.ARW", "A0010001.WAV", "Z0010001.ARW")
-	assertPrimaryMember(t, "A0010001.TIF", "A0010001.MOV", "A0010001.TIF")
-	assertPrimaryMember(t, "Z0010001.TIF", "A0010001.WAV", "Z0010001.TIF")
-
-	// Then a video.
-	assertPrimaryMember(t, "A0010001.MP4", "A0010001.AAC", "A0010001.MP4")
-	assertPrimaryMember(t, "Z0010001.MP4", "A0010001.THM", "Z0010001.MP4")
-
-	// Then any other file except a THM, in either case.
-	assertPrimaryMember(t, "Z0010001.WAV", "A0010001.THM", "Z0010001.WAV")
-	assertPrimaryMember(t, "a0010001.wav", "a0010001.thm", "a0010001.wav")
-
-	// A THM is primary only when the group holds nothing else.
-	assertPrimaryMember(t, "A0010001.THM", "A0010001.THM")
-
-	// Among equals, the first in name order wins.
-	assertPrimaryMember(t, "A0010001.THM", "A0010001.THM", "Z0010001.THM")
-	assertPrimaryMember(t, "A0010001.WAV", "A0010001.WAV", "Z0010001.XML")
-}

pkg/dcf/helpers.go

@@ -1,7 +1,6 @@
 package dcf
 
 import (
-	"context"
 	"fmt"
 	"log/slog"
 	"os"
@@ -10,19 +9,12 @@ import (
 	"github.com/shirou/gopsutil/disk"
 )
 
-func findAllMountPoints(ctx context.Context) ([]string, error) {
+func findAllMountPoints() ([]string, error) {
 	mountpoints := []string{}
 
-	// disk.PartitionsWithContext does not check ctx on Linux.
+	partitions, err := disk.Partitions(false) // physical devices only, so false
-	err := ctx.Err()
 	if err != nil {
-		return nil, fmt.Errorf("listing the mounted filesystems: %w", err)
+		return nil, err
-	}
-
-	// physical devices only, so false
-	partitions, err := disk.PartitionsWithContext(ctx, false)
-	if err != nil {
-		return nil, fmt.Errorf("listing the mounted filesystems: %w", err)
 	}
 
 	for _, partition := range partitions {
@@ -34,18 +26,21 @@ func findAllMountPoints(ctx context.Context) ([]string, error) {
 	return mountpoints, nil
 }
 
-// findDCFMountPoints returns the paths of the mountpoints that hold a DCF store.
+// findDCFMountPoints returns a list of strings of the paths of mountpoints
-func findDCFMountPoints(ctx context.Context) ([]string, error) {
+// that hold a DCF store. Its only argument is an integer of how many mountpoints
-	mountpoints, err := findAllMountPoints(ctx)
+// to return. If the argument is 0, all mountpoints are returned.
+func findDCFMountPoints(requestedCount int) ([]string, error) {
+	mountpoints, err := findAllMountPoints()
 	if err != nil {
 		return nil, err
 	}
 
-	return filterDCFMountPoints(mountpoints), nil
+	return filterDCFMountPoints(mountpoints, requestedCount), nil
 }
 
-// filterDCFMountPoints returns the mountpoints that hold a DCF store.
+// filterDCFMountPoints returns the first requestedCount of the mountpoints that
-func filterDCFMountPoints(mountpoints []string) []string {
+// hold a DCF store. If requestedCount is 0, it returns all of them.
+func filterDCFMountPoints(mountpoints []string, requestedCount int) []string {
 	filteredMountpoints := []string{}
 
 	for _, mountpoint := range mountpoints {
@@ -56,6 +51,9 @@ func filterDCFMountPoints(mountpoints []string) []string {
 		slog.Debug(fmt.Sprintf("Keeping mountpoint %s\n", mountpoint))
 
 		filteredMountpoints = append(filteredMountpoints, mountpoint)
+		if (requestedCount > 0) && (len(filteredMountpoints) >= requestedCount) {
+			break
+		}
 	}
 
 	return filteredMountpoints

pkg/dcf/helpers_internal_test.go

@@ -72,16 +72,29 @@ func TestIsDCFMountPointIgnoresSymlink(t *testing.T) {
 	}
 }
 
-func TestFilterDCFMountPointsKeepsThoseHoldingAStore(t *testing.T) {
+func TestFilterDCFMountPointsReturnsRequestedCount(t *testing.T) {
 	t.Parallel()
 
 	first := newMountPoint(t, "DCIM")
 	second := newMountPoint(t, "PRIVATE/M4ROOT")
+	third := newMountPoint(t, "DCIM")
 
-	got := filterDCFMountPoints([]string{newMountPoint(t), first, second})
+	// This one holds no DCF store, so it must not use up the requested count.
+	mountpoints := []string{newMountPoint(t), first, second, third}
 
-	want := []string{first, second}
+	cases := map[int][]string{
-	if !slices.Equal(got, want) {
+		0: {first, second, third},
-		t.Errorf("filterDCFMountPoints = %v, want %v", got, want)
+		1: {first},
+		2: {first, second},
+		3: {first, second, third},
+		4: {first, second, third},
+	}
+
+	for requestedCount, want := range cases {
+		got := filterDCFMountPoints(mountpoints, requestedCount)
+		if !slices.Equal(got, want) {
+			t.Errorf("filterDCFMountPoints(%d) = %v, want %v",
+				requestedCount, got, want)
+		}
 	}
 }

pkg/dcf/import.go

@@ -1,279 +0,0 @@
-package dcf
-
-import (
-	"context"
-	"crypto/sha256"
-	"encoding/hex"
-	"errors"
-	"fmt"
-	"io"
-	"io/fs"
-	"os"
-	"path"
-	"path/filepath"
-	"time"
-)
-
-// The modes of what Import creates. Only the user who ran it can read the copies.
-const (
-	importDirectoryMode = 0o750
-	importFileMode      = 0o600
-)
-
-var errHashMismatch = errors.New("the SHA256 hash of the copy differs from the source")
-
-// ImportResult lists what Store.Import did with each file, by destination path.
-type ImportResult struct {
-	// Copied holds the copies this import wrote and verified.
-	Copied []string
-	// Skipped holds the paths that already held a file with the same SHA256 hash.
-	Skipped []string
-	// Conflicts holds the paths that already held anything else. Import left it
-	// alone and did not copy the file.
-	Conflicts []string
-}
-
-// importFile is one file for Import to copy, and the path to copy it to.
-type importFile struct {
-	source *Object
-	target string
-}
-
-// Import copies the files of the store to dest, and verifies each copy against
-// the SHA256 hash of its source. It copies every member of every file group, and
-// the images and videos under PRIVATE/M4ROOT. It only reads the card.
-//
-// Each file goes to dest/YYYY-MM-DD/<file name>, from its modification time. Every
-// member of a file group goes to the day of its primary member, so a group never
-// splits across two folders.
-//
-// A file with the same hash already at the path is skipped. Anything else there is
-// a conflict, which is not an error. Import never overwrites anything.
-//
-// One file that fails does not stop the others. The returned error joins the
-// failures, each naming its file, and the result still lists what was done. When
-// ctx is cancelled, the import stops at once and removes the partial copy, and the
-// error matches ctx.Err().
-func (d *Store) Import(ctx context.Context, dest string) (ImportResult, error) {
-	var (
-		result   ImportResult
-		failures []error
-	)
-
-	for _, file := range d.importFiles(dest) {
-		err := ctx.Err()
-		if err != nil {
-			failures = append(failures, fmt.Errorf("import stopped: %w", err))
-
-			break
-		}
-
-		err = copyFile(ctx, file, &result)
-		if err != nil {
-			failures = append(failures,
-				fmt.Errorf("importing %s: %w", file.source.FullFilePath(), err))
-		}
-	}
-
-	return result, errors.Join(failures...)
-}
-
-// importFiles lists the files of the store that Import copies to dest.
-func (d *Store) importFiles(dest string) []importFile {
-	var files []importFile
-
-	add := func(source *Object, day time.Time) {
-		name := path.Base(source.Path)
-
-		files = append(files, importFile{
-			source: source,
-			target: filepath.Join(dest, day.Format(time.DateOnly), name),
-		})
-	}
-
-	for _, directory := range d.Directories {
-		for _, group := range directory.FileGroups {
-			for _, member := range group.Members {
-				add(member, group.Primary.ModTime)
-			}
-		}
-	}
-
-	// The files under PRIVATE/M4ROOT are the ones with no DCF numbers.
-	for _, image := range d.Images {
-		if image.DirectoryNumber == 0 {
-			add(&image.Object, image.ModTime)
-		}
-	}
-
-	for _, video := range d.Videos {
-		if video.DirectoryNumber == 0 {
-			add(&video.Object, video.ModTime)
-		}
-	}
-
-	return files
-}
-
-// copyFile copies one file, and adds its target to the list in result that says
-// what happened. It adds the target to no list when it returns an error.
-func copyFile(ctx context.Context, file importFile, result *ImportResult) error {
-	sourceHash, err := file.source.hash(ctx)
-	if err != nil {
-		return err
-	}
-
-	err = os.MkdirAll(filepath.Dir(file.target), importDirectoryMode)
-	if err != nil {
-		return err
-	}
-
-	// O_EXCL fails on anything already at the path, even a symlink, so nothing
-	// there can be overwritten.
-	target, err := os.OpenFile(
-		file.target, os.O_WRONLY|os.O_CREATE|os.O_EXCL, importFileMode,
-	)
-	if errors.Is(err, fs.ErrExist) {
-		return checkExisting(ctx, file.target, sourceHash, result)
-	}
-
-	if err != nil {
-		return err
-	}
-
-	err = writeCopy(ctx, file, target, sourceHash)
-	if err != nil {
-		return errors.Join(err, os.Remove(file.target))
-	}
-
-	result.Copied = append(result.Copied, file.target)
-
-	return nil
-}
-
-// checkExisting adds target to the skipped files if it is a file with the given
-// hash, and to the conflicts if it is anything else.
-func checkExisting(
-	ctx context.Context,
-	target, sourceHash string,
-	result *ImportResult,
-) error {
-	info, err := os.Lstat(target)
-	if err != nil {
-		return err
-	}
-
-	if !info.Mode().IsRegular() {
-		result.Conflicts = append(result.Conflicts, target)
-
-		return nil
-	}
-
-	targetHash, err := hashOnDisk(ctx, target)
-	if err != nil {
-		return err
-	}
-
-	if targetHash == sourceHash {
-		result.Skipped = append(result.Skipped, target)
-	} else {
-		result.Conflicts = append(result.Conflicts, target)
-	}
-
-	return nil
-}
-
-// writeCopy fills the new file target from the source, and closes it. It then
-// reads the written file back to compare its hash with the hash of the source.
-func writeCopy(
-	ctx context.Context,
-	file importFile,
-	target *os.File,
-	sourceHash string,
-) error {
-	err := writeAndClose(ctx, file.source, target)
-	if err != nil {
-		return err
-	}
-
-	targetHash, err := hashOnDisk(ctx, file.target)
-	if err != nil {
-		return err
-	}
-
-	if targetHash != sourceHash {
-		return errHashMismatch
-	}
-
-	// The zero time leaves the access time as it is.
-	return os.Chtimes(file.target, time.Time{}, file.source.ModTime)
-}
-
-// writeAndClose writes the bytes of source to target, syncs target and closes it.
-func writeAndClose(ctx context.Context, source *Object, target *os.File) error {
-	defer func() { _ = target.Close() }()
-
-	sourceFile, err := source.fsys.Open(source.Path)
-	if err != nil {
-		return err
-	}
-
-	defer func() { _ = sourceFile.Close() }()
-
-	_, err = io.Copy(target, contextReader(ctx, sourceFile))
-	if err != nil {
-		return err
-	}
-
-	err = target.Sync()
-	if err != nil {
-		return err
-	}
-
-	return target.Close()
-}
-
-// hashOnDisk returns the SHA256 hash of the file at filePath on the local
-// filesystem.
-func hashOnDisk(ctx context.Context, filePath string) (string, error) {
-	return hashFile(ctx, os.DirFS(filepath.Dir(filePath)), filepath.Base(filePath))
-}
-
-// hashFile returns the SHA256 hash of the named file as a hex string.
-func hashFile(ctx context.Context, fsys fs.FS, name string) (string, error) {
-	file, err := fsys.Open(name)
-	if err != nil {
-		return "", err
-	}
-
-	defer func() { _ = file.Close() }()
-
-	hash := sha256.New()
-
-	_, err = io.Copy(hash, contextReader(ctx, file))
-	if err != nil {
-		return "", err
-	}
-
-	return hex.EncodeToString(hash.Sum(nil)), nil
-}
-
-// readerFunc is a function that works as an io.Reader.
-type readerFunc func([]byte) (int, error)
-
-func (f readerFunc) Read(p []byte) (int, error) {
-	return f(p)
-}
-
-// contextReader returns a reader that fails with ctx.Err() once ctx is cancelled,
-// so a copy stops inside a file.
-func contextReader(ctx context.Context, reader io.Reader) io.Reader {
-	return readerFunc(func(p []byte) (int, error) {
-		err := ctx.Err()
-		if err != nil {
-			return 0, err
-		}
-
-		return reader.Read(p)
-	})
-}

pkg/dcf/import_internal_test.go

@@ -1,521 +0,0 @@
-package dcf
-
-import (
-	"context"
-	"errors"
-	"io/fs"
-	"maps"
-	"os"
-	"path/filepath"
-	"strings"
-	"testing"
-	"testing/fstest"
-	"time"
-)
-
-// testDay is the folder that a file from cardFile goes to. The other constants
-// are the paths and contents of the files on most cards in these tests.
-const (
-	testDay = "2026-10-03"
-
-	firstJPG      = "DCIM/100ABCDE/DSC00011.JPG"
-	firstJPGData  = "first jpeg"
-	secondJPG     = "DCIM/100ABCDE/DSC00012.JPG"
-	secondJPGData = "second jpeg"
-	testClip      = "PRIVATE/M4ROOT/CLIP/C0011.MP4"
-	testClipData  = "clip"
-)
-
-// cardFile returns a file on a card, modified at noon on testDay.
-func cardFile(contents string) *fstest.MapFile {
-	return &fstest.MapFile{
-		Data:    []byte(contents),
-		ModTime: time.Date(2026, 10, 3, 12, 0, 0, 0, time.UTC),
-	}
-}
-
-// inTestDay returns the paths of the named files in the testDay folder of dest.
-func inTestDay(dest string, names ...string) []string {
-	paths := make([]string, 0, len(names))
-
-	for _, name := range names {
-		paths = append(paths, filepath.Join(dest, testDay, name))
-	}
-
-	return paths
-}
-
-// assertDest checks that dest holds exactly the given files, as a map from each
-// file's path under dest to its contents.
-func assertDest(t *testing.T, dest string, want map[string]string) {
-	t.Helper()
-
-	fsys := os.DirFS(dest)
-	got := map[string]string{}
-
-	err := fs.WalkDir(fsys, ".",
-		func(name string, entry fs.DirEntry, err error) error {
-			if err != nil || !entry.Type().IsRegular() {
-				return err
-			}
-
-			data, err := fs.ReadFile(fsys, name)
-			got[name] = string(data)
-
-			return err
-		})
-	if err != nil {
-		t.Fatalf("reading %s: %v", dest, err)
-	}
-
-	if !maps.Equal(got, want) {
-		t.Errorf("destination holds %q, want %q", got, want)
-	}
-}
-
-func assertEmptyDirectory(t *testing.T, directory string) {
-	t.Helper()
-
-	entries, err := os.ReadDir(directory)
-	if err != nil {
-		t.Fatalf("ReadDir: %v", err)
-	}
-
-	if len(entries) != 0 {
-		t.Errorf("%s holds %v, want nothing", directory, entries)
-	}
-}
-
-// addDestFile writes a file at the named path under dest.
-func addDestFile(t *testing.T, dest, name, contents string) {
-	t.Helper()
-
-	fullPath := filepath.Join(dest, name)
-
-	err := os.MkdirAll(filepath.Dir(fullPath), 0o750)
-	if err != nil {
-		t.Fatalf("MkdirAll: %v", err)
-	}
-
-	err = os.WriteFile(fullPath, []byte(contents), 0o600)
-	if err != nil {
-		t.Fatalf("WriteFile: %v", err)
-	}
-}
-
-func TestImportCopiesEveryFileAndKeepsItsModificationTime(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-
-	store := mustParseStore(t, fstest.MapFS{
-		"DCIM/100ABCDE/DSC00011.ARW":         cardFile("raw"),
-		firstJPG:                             cardFile(firstJPGData),
-		"DCIM/101ABCDE/MVI_0012.MP4":         cardFile("video"),
-		"DCIM/101ABCDE/MVI_0012.THM":         cardFile("thumbnail"),
-		"DCIM/MISC/DSC00013.JPG":             cardFile("not conforming"),
-		testClip:                             cardFile(testClipData),
-		"PRIVATE/M4ROOT/CLIP/C0011M01.XML":   cardFile("neither image nor video"),
-		"PRIVATE/M4ROOT/THMBNL/C0011T01.JPG": cardFile("clip thumbnail"),
-	})
-
-	result, err := store.Import(t.Context(), dest)
-	if err != nil {
-		t.Fatalf("Import: %v", err)
-	}
-
-	assertPaths(t, "Copied", result.Copied, inTestDay(dest,
-		"DSC00011.ARW",
-		"DSC00011.JPG",
-		"MVI_0012.MP4",
-		"MVI_0012.THM",
-		"C0011T01.JPG",
-		"C0011.MP4",
-	)...)
-	assertPaths(t, "Skipped", result.Skipped)
-	assertPaths(t, "Conflicts", result.Conflicts)
-
-	assertDest(t, dest, map[string]string{
-		testDay + "/DSC00011.ARW": "raw",
-		testDay + "/DSC00011.JPG": firstJPGData,
-		testDay + "/MVI_0012.MP4": "video",
-		testDay + "/MVI_0012.THM": "thumbnail",
-		testDay + "/C0011.MP4":    testClipData,
-		testDay + "/C0011T01.JPG": "clip thumbnail",
-	})
-
-	for _, copied := range result.Copied {
-		info, err := os.Stat(copied)
-		if err != nil {
-			t.Fatalf("Stat: %v", err)
-		}
-
-		if want := cardFile("").ModTime; !info.ModTime().Equal(want) {
-			t.Errorf("%s modified at %v, want %v", copied, info.ModTime(), want)
-		}
-	}
-}
-
-func TestImportTwiceSkipsEveryFileTheSecondTime(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-
-	store := mustParseStore(t, fstest.MapFS{
-		firstJPG: cardFile(firstJPGData),
-		testClip: cardFile(testClipData),
-	})
-
-	_, err := store.Import(t.Context(), dest)
-	if err != nil {
-		t.Fatalf("first Import: %v", err)
-	}
-
-	result, err := store.Import(t.Context(), dest)
-	if err != nil {
-		t.Fatalf("second Import: %v", err)
-	}
-
-	assertPaths(t, "Copied", result.Copied)
-	assertPaths(t, "Skipped", result.Skipped,
-		inTestDay(dest, "DSC00011.JPG", "C0011.MP4")...)
-	assertPaths(t, "Conflicts", result.Conflicts)
-
-	assertDest(t, dest, map[string]string{
-		testDay + "/DSC00011.JPG": firstJPGData,
-		testDay + "/C0011.MP4":    testClipData,
-	})
-}
-
-func TestImportLeavesADifferentFileAloneAndReportsAConflict(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-	addDestFile(t, dest, testDay+"/DSC00011.JPG", "different")
-
-	store := mustParseStore(t, fstest.MapFS{
-		firstJPG:  cardFile(firstJPGData),
-		secondJPG: cardFile(secondJPGData),
-	})
-
-	result, err := store.Import(t.Context(), dest)
-	if err != nil {
-		t.Fatalf("Import: %v", err)
-	}
-
-	assertPaths(t, "Copied", result.Copied, inTestDay(dest, "DSC00012.JPG")...)
-	assertPaths(t, "Skipped", result.Skipped)
-	assertPaths(t, "Conflicts", result.Conflicts, inTestDay(dest, "DSC00011.JPG")...)
-
-	assertDest(t, dest, map[string]string{
-		testDay + "/DSC00011.JPG": "different",
-		testDay + "/DSC00012.JPG": secondJPGData,
-	})
-}
-
-func TestImportReportsAConflictBetweenTwoFilesWithOneName(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-
-	store := mustParseStore(t, fstest.MapFS{
-		firstJPG:                     cardFile(firstJPGData),
-		"DCIM/101ABCDE/DSC00011.JPG": cardFile(secondJPGData),
-	})
-
-	result, err := store.Import(t.Context(), dest)
-	if err != nil {
-		t.Fatalf("Import: %v", err)
-	}
-
-	assertPaths(t, "Copied", result.Copied, inTestDay(dest, "DSC00011.JPG")...)
-	assertPaths(t, "Conflicts", result.Conflicts, inTestDay(dest, "DSC00011.JPG")...)
-	assertDest(t, dest, map[string]string{testDay + "/DSC00011.JPG": firstJPGData})
-}
-
-func TestImportReportsAConflictAtADirectoryOrASymlink(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-
-	// The symlink points at a file with the same bytes, which must not count.
-	outside := newCardOnDisk(t, "OUTSIDE.JPG")
-
-	err := os.MkdirAll(filepath.Join(dest, testDay, "DSC00011.JPG"), 0o750)
-	if err != nil {
-		t.Fatalf("MkdirAll: %v", err)
-	}
-
-	addSymlink(t, dest, testDay+"/DSC00012.JPG", filepath.Join(outside, "OUTSIDE.JPG"))
-
-	store := mustParseStore(t, fstest.MapFS{
-		firstJPG:  cardFile("abc"),
-		secondJPG: cardFile("abc"),
-	})
-
-	result, err := store.Import(t.Context(), dest)
-	if err != nil {
-		t.Fatalf("Import: %v", err)
-	}
-
-	assertPaths(t, "Copied", result.Copied)
-	assertPaths(t, "Skipped", result.Skipped)
-	assertPaths(t, "Conflicts", result.Conflicts,
-		inTestDay(dest, "DSC00011.JPG", "DSC00012.JPG")...)
-}
-
-func TestImportPutsAFileGroupInTheFolderOfItsPrimaryMember(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-
-	beforeMidnight := time.Date(2026, 10, 3, 23, 59, 59, 0, time.UTC)
-	afterMidnight := time.Date(2026, 10, 4, 0, 0, 1, 0, time.UTC)
-
-	store := mustParseStore(t, fstest.MapFS{
-		"DCIM/100ABCDE/DSC00011.ARW": {Data: []byte("raw"), ModTime: afterMidnight},
-		firstJPG:                     {Data: []byte("jpeg"), ModTime: beforeMidnight},
-		secondJPG:                    {Data: []byte("next"), ModTime: afterMidnight},
-	})
-
-	_, err := store.Import(t.Context(), dest)
-	if err != nil {
-		t.Fatalf("Import: %v", err)
-	}
-
-	assertDest(t, dest, map[string]string{
-		"2026-10-03/DSC00011.ARW": "raw",
-		"2026-10-03/DSC00011.JPG": "jpeg",
-		"2026-10-04/DSC00012.JPG": "next",
-	})
-
-	// The copy keeps its own modification time, whichever folder it is in.
-	info, err := os.Stat(filepath.Join(dest, "2026-10-03/DSC00011.ARW"))
-	if err != nil {
-		t.Fatalf("Stat: %v", err)
-	}
-
-	if !info.ModTime().Equal(afterMidnight) {
-		t.Errorf("modified at %v, want %v", info.ModTime(), afterMidnight)
-	}
-}
-
-// changingFS is a card whose file at name holds other bytes from its second read
-// on. It counts the reads in opens.
-type changingFS struct {
-	fstest.MapFS
-
-	name  string
-	opens *int
-}
-
-func (f changingFS) Open(name string) (fs.File, error) {
-	if name == f.name {
-		*f.opens++
-		if *f.opens > 1 {
-			return fstest.MapFS{name: cardFile("other bytes")}.Open(name)
-		}
-	}
-
-	return f.MapFS.Open(name)
-}
-
-func TestImportRemovesACopyThatDoesNotMatchItsSource(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-	opens := 0
-
-	store := mustParseStore(t, changingFS{
-		MapFS: fstest.MapFS{
-			firstJPG:  cardFile(firstJPGData),
-			secondJPG: cardFile(secondJPGData),
-		},
-		name:  firstJPG,
-		opens: &opens,
-	})
-
-	result, err := store.Import(t.Context(), dest)
-	if !errors.Is(err, errHashMismatch) {
-		t.Fatalf("Import error = %v, want %v", err, errHashMismatch)
-	}
-
-	if !strings.Contains(err.Error(), firstJPG) {
-		t.Errorf("Import error = %v, want one naming %s", err, firstJPG)
-	}
-
-	assertPaths(t, "Copied", result.Copied, inTestDay(dest, "DSC00012.JPG")...)
-	assertDest(t, dest, map[string]string{testDay + "/DSC00012.JPG": secondJPGData})
-}
-
-func TestImportCopiesTheOtherFilesWhenOneCannotBeRead(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-
-	store := mustParseStore(t, failingFS{
-		MapFS: fstest.MapFS{
-			firstJPG:  cardFile(firstJPGData),
-			secondJPG: cardFile(secondJPGData),
-			testClip:  cardFile(testClipData),
-		},
-		call: "Open",
-		name: firstJPG,
-	})
-
-	result, err := store.Import(t.Context(), dest)
-	if !errors.Is(err, fs.ErrPermission) {
-		t.Fatalf("Import error = %v, want %v", err, fs.ErrPermission)
-	}
-
-	if !strings.Contains(err.Error(), firstJPG) {
-		t.Errorf("Import error = %v, want one naming %s", err, firstJPG)
-	}
-
-	assertPaths(t, "Copied", result.Copied,
-		inTestDay(dest, "DSC00012.JPG", "C0011.MP4")...)
-	assertDest(t, dest, map[string]string{
-		testDay + "/DSC00012.JPG": secondJPGData,
-		testDay + "/C0011.MP4":    testClipData,
-	})
-}
-
-func TestImportNamesEveryFileThatFails(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-
-	// A plain file where the day folder belongs fails every file of that day.
-	addDestFile(t, dest, testDay, "not a folder")
-
-	store := mustParseStore(t, fstest.MapFS{
-		firstJPG:  cardFile(firstJPGData),
-		secondJPG: cardFile(secondJPGData),
-	})
-
-	result, err := store.Import(t.Context(), dest)
-	if err == nil {
-		t.Fatal("Import returned no error")
-	}
-
-	for _, name := range []string{firstJPG, secondJPG} {
-		if !strings.Contains(err.Error(), name) {
-			t.Errorf("Import error = %v, want one naming %s", err, name)
-		}
-	}
-
-	assertPaths(t, "Copied", result.Copied)
-}
-
-func TestImportOfObjectBuiltByHandReturnsError(t *testing.T) {
-	t.Parallel()
-
-	dest := t.TempDir()
-
-	store := &Store{Images: []*Image{{Object: Object{Path: "DSC00011.JPG"}}}}
-
-	_, err := store.Import(t.Context(), dest)
-	if !errors.Is(err, fs.ErrInvalid) {
-		t.Fatalf("Import error = %v, want %v", err, fs.ErrInvalid)
-	}
-
-	assertEmptyDirectory(t, dest)
-}
-
-// cancelingFile is an open file that cancels the import after each read.
-type cancelingFile struct {
-	fs.File
-
-	cancel context.CancelFunc
-}
-
-func (f cancelingFile) Read(p []byte) (int, error) {
-	n, err := f.File.Read(p)
-
-	f.cancel()
-
-	return n, err
-}
-
-// cancelingReadFS is a card that cancels the import during the read of the named
-// file, the time that file is opened for the openCount-th time. It counts the
-// reads in opens.
-type cancelingReadFS struct {
-	fstest.MapFS
-
-	name      string
-	openCount int
-	opens     *int
-	cancel    context.CancelFunc
-}
-
-func (f cancelingReadFS) Open(name string) (fs.File, error) {
-	file, err := f.MapFS.Open(name)
-	if err != nil || name != f.name {
-		return file, err
-	}
-
-	*f.opens++
-	if *f.opens != f.openCount {
-		return file, nil
-	}
-
-	return cancelingFile{File: file, cancel: f.cancel}, nil
-}
-
-func TestImportStopsInsideAFileWhenCancelledAndRemovesThePartialCopy(t *testing.T) {
-	t.Parallel()
-
-	// The first read of a file is hashing it, and the second is copying it.
-	for _, openCount := range []int{1, 2} {
-		ctx, cancel := context.WithCancel(t.Context())
-		dest := t.TempDir()
-		opens := 0
-
-		store := mustParseStore(t, cancelingReadFS{
-			MapFS: fstest.MapFS{
-				// Larger than one read, so the cancellation falls inside the file.
-				firstJPG:  {Data: make([]byte, 1<<20)},
-				secondJPG: cardFile(secondJPGData),
-			},
-			name:      firstJPG,
-			openCount: openCount,
-			opens:     &opens,
-			cancel:    cancel,
-		})
-
-		result, err := store.Import(ctx, dest)
-		if !errors.Is(err, context.Canceled) {
-			t.Errorf("cancelled in read %d: error = %v, want %v",
-				openCount, err, context.Canceled)
-		}
-
-		assertPaths(t, "Copied", result.Copied)
-		assertDest(t, dest, map[string]string{})
-
-		if opens != openCount {
-			t.Errorf("cancelled in read %d: file opened %d times", openCount, opens)
-		}
-
-		cancel()
-	}
-}
-
-func TestImportCopiesNothingWhenAlreadyCancelled(t *testing.T) {
-	t.Parallel()
-
-	ctx, cancel := context.WithCancel(t.Context())
-	cancel()
-
-	dest := t.TempDir()
-
-	store := mustParseStore(t, fstest.MapFS{firstJPG: cardFile(firstJPGData)})
-
-	result, err := store.Import(ctx, dest)
-	if !errors.Is(err, context.Canceled) {
-		t.Fatalf("Import error = %v, want %v", err, context.Canceled)
-	}
-
-	assertPaths(t, "Copied", result.Copied)
-	assertEmptyDirectory(t, dest)
-}

pkg/dcf/parse.go

@@ -1,7 +1,6 @@
 package dcf
 
 import (
-	"context"
 	"errors"
 	"fmt"
 	"io/fs"
@@ -29,13 +28,13 @@ var (
 // point. The root argument is the path of that mount point. Only DCIM and
 // PRIVATE/M4ROOT are read. A card can lack either one. A symlink is never
 // followed. An error names the mount point, because fsys reports only paths
-// inside it. When ctx is cancelled, the read stops before the next directory.
+// inside it.
-func parseStore(ctx context.Context, fsys fs.FS, root string) (*Store, error) {
+func parseStore(fsys fs.FS, root string) (*Store, error) {
 	store := &Store{RootDirectory: root}
 
-	err := parseDCIM(ctx, fsys, store)
+	err := parseDCIM(fsys, store)
 	if err == nil {
-		err = parseM4Root(ctx, fsys, store)
+		err = parseM4Root(fsys, store)
 	}
 
 	if err != nil {
@@ -69,26 +68,16 @@ func hasDirectory(fsys fs.FS, name string) (bool, error) {
 	return info.IsDir(), nil
 }
 
-// readDir returns the entries of the named directory, unless ctx is cancelled.
-func readDir(ctx context.Context, fsys fs.FS, name string) ([]fs.DirEntry, error) {
-	err := ctx.Err()
-	if err != nil {
-		return nil, err
-	}
-
-	return fs.ReadDir(fsys, name)
-}
-
 // parseDCIM adds the DCF directories under DCIM to store. Everything else there
 // is not conforming. That includes directories that share a directory number,
 // which section 7.1.2 of the specification treats as non-DCF directories.
-func parseDCIM(ctx context.Context, fsys fs.FS, store *Store) error {
+func parseDCIM(fsys fs.FS, store *Store) error {
 	found, err := hasDirectory(fsys, dcimDirectory)
 	if err != nil || !found {
 		return err
 	}
 
-	entries, err := readDir(ctx, fsys, dcimDirectory)
+	entries, err := fs.ReadDir(fsys, dcimDirectory)
 	if err != nil {
 		return err
 	}
@@ -105,9 +94,9 @@ func parseDCIM(ctx context.Context, fsys fs.FS, store *Store) error {
 		number := parseNumber(dcfDirectoryName, entry.Name())
 
 		if entry.IsDir() && number != 0 && directoriesWithNumber[number] == 1 {
-			err = parseDirectory(ctx, fsys, store, entry.Name(), number)
+			err = parseDirectory(fsys, store, entry.Name(), number)
 		} else {
-			err = addNonConforming(ctx, fsys, store, dcimDirectory, entry)
+			err = addNonConforming(fsys, store, dcimDirectory, entry)
 		}
 
 		if err != nil {
@@ -123,16 +112,10 @@ func parseDCIM(ctx context.Context, fsys fs.FS, store *Store) error {
 // Everything else there is not conforming. That includes JPG files that share a
 // file number, which section 7.2.2 of the specification says must not show DCF
 // numbers. Other files that share a file number do conform.
-func parseDirectory(
+func parseDirectory(fsys fs.FS, store *Store, name string, number int) error {
-	ctx context.Context,
-	fsys fs.FS,
-	store *Store,
-	name string,
-	number int,
-) error {
 	directoryPath := path.Join(dcimDirectory, name)
 
-	entries, err := readDir(ctx, fsys, directoryPath)
+	entries, err := fs.ReadDir(fsys, directoryPath)
 	if err != nil {
 		return err
 	}
@@ -152,7 +135,7 @@ func parseDirectory(
 		sharedJPG := isJPG(entry.Name()) && jpgsWithNumber[fileNumber] > 1
 
 		if !entry.Type().IsRegular() || fileNumber == 0 || sharedJPG {
-			err = addNonConforming(ctx, fsys, store, directoryPath, entry)
+			err = addNonConforming(fsys, store, directoryPath, entry)
 			if err != nil {
 				return err
 			}
@@ -162,7 +145,7 @@ func parseDirectory(
 
 		entryPath := path.Join(directoryPath, entry.Name())
 
-		object, err := newObject(fsys, store, entryPath, entry)
+		object, err := newObject(store, entryPath, entry)
 		if err != nil {
 			return err
 		}
@@ -174,7 +157,6 @@ func parseDirectory(
 		addMedia(store, object)
 	}
 
-	directory.FileGroups = newFileGroups(directory.Objects)
 	store.Directories = append(store.Directories, directory)
 
 	return nil
@@ -184,7 +166,7 @@ func parseDirectory(
 // naming rules do not apply there, so these files have no DCF numbers. It skips
 // a symlink. It also skips a name that is not valid UTF-8, because fs.FS refuses
 // to open one.
-func parseM4Root(ctx context.Context, fsys fs.FS, store *Store) error {
+func parseM4Root(fsys fs.FS, store *Store) error {
 	found, err := hasDirectory(fsys, m4RootDirectory)
 	if err != nil || !found {
 		return err
@@ -202,16 +184,11 @@ func parseM4Root(ctx context.Context, fsys fs.FS, store *Store) error {
 				return fs.SkipDir
 			}
 
-			// fs.WalkDir reads a directory right after this call for it.
-			if entry.IsDir() {
-				return ctx.Err()
-			}
-
 			if !entry.Type().IsRegular() || !validName {
 				return nil
 			}
 
-			object, err := newObject(fsys, store, filePath, entry)
+			object, err := newObject(store, filePath, entry)
 			if err != nil {
 				return err
 			}
@@ -226,13 +203,7 @@ func parseM4Root(ctx context.Context, fsys fs.FS, store *Store) error {
 // conforming. If the entry is a directory, it lists everything inside it too. It
 // does not follow a symlink. It does not read a directory whose name is not
 // valid UTF-8, because fs.FS refuses to open one.
-func addNonConforming(
+func addNonConforming(fsys fs.FS, store *Store, dir string, entry fs.DirEntry) error {
-	ctx context.Context,
-	fsys fs.FS,
-	store *Store,
-	dir string,
-	entry fs.DirEntry,
-) error {
 	entryPath := path.Join(dir, entry.Name())
 	store.NonConforming = append(store.NonConforming, entryPath)
 
@@ -240,13 +211,13 @@ func addNonConforming(
 		return nil
 	}
 
-	entries, err := readDir(ctx, fsys, entryPath)
+	entries, err := fs.ReadDir(fsys, entryPath)
 	if err != nil {
 		return err
 	}
 
 	for _, inner := range entries {
-		err = addNonConforming(ctx, fsys, store, entryPath, inner)
+		err = addNonConforming(fsys, store, entryPath, inner)
 		if err != nil {
 			return err
 		}
@@ -256,12 +227,7 @@ func addNonConforming(
 }
 
 // newObject returns the Object for the file at filePath, with no DCF numbers.
-func newObject(
+func newObject(store *Store, filePath string, entry fs.DirEntry) (Object, error) {
-	fsys fs.FS,
-	store *Store,
-	filePath string,
-	entry fs.DirEntry,
-) (Object, error) {
 	info, err := entry.Info()
 	if err != nil {
 		return Object{}, err
@@ -272,8 +238,6 @@ func newObject(
 		Path:         filePath,
 		Size:         info.Size(),
 		Extension:    path.Ext(filePath),
-		ModTime:      info.ModTime(),
-		fsys:         fsys,
 	}, nil
 }
 

pkg/dcf/parse_internal_test.go

@@ -1,7 +1,6 @@
 package dcf
 
 import (
-	"context"
 	"errors"
 	"io/fs"
 	"os"
@@ -66,7 +65,7 @@ func addSymlink(t *testing.T, root, name, target string) {
 func mustParseStore(t *testing.T, fsys fs.FS) *Store {
 	t.Helper()
 
-	store, err := parseStore(t.Context(), fsys, testRoot)
+	store, err := parseStore(fsys, testRoot)
 	if err != nil {
 		t.Fatalf("parseStore: %v", err)
 	}
@@ -114,16 +113,6 @@ func directoryNumbers(store *Store) []int {
 	return numbers
 }
 
-// wantDirectory returns the Directory that parseStore should build for objects.
-func wantDirectory(number int, name string, objects ...*Object) *Directory {
-	return &Directory{
-		Number:     number,
-		Name:       name,
-		Objects:    objects,
-		FileGroups: newFileGroups(objects),
-	}
-}
-
 func assertPaths(t *testing.T, what string, got []string, want ...string) {
 	t.Helper()
 
@@ -158,7 +147,6 @@ func TestParseStorePutsEachFileWhereItBelongs(t *testing.T) {
 		Extension:       ".ARW",
 		DirectoryNumber: 100,
 		FileNumber:      1,
-		fsys:            card,
 	}
 	mp4 := Object{
 		DCFStoreRoot:    testRoot,
@@ -167,7 +155,6 @@ func TestParseStorePutsEachFileWhereItBelongs(t *testing.T) {
 		Extension:       ".MP4",
 		DirectoryNumber: 101,
 		FileNumber:      2,
-		fsys:            card,
 	}
 	thm := Object{
 		DCFStoreRoot:    testRoot,
@@ -176,19 +163,17 @@ func TestParseStorePutsEachFileWhereItBelongs(t *testing.T) {
 		Extension:       ".THM",
 		DirectoryNumber: 101,
 		FileNumber:      2,
-		fsys:            card,
 	}
 	clip := Object{
 		DCFStoreRoot: testRoot,
 		Path:         "PRIVATE/M4ROOT/CLIP/C0002.MP4",
 		Size:         400,
 		Extension:    ".MP4",
-		fsys:         card,
 	}
 
 	wantDirectories := []*Directory{
-		wantDirectory(100, "100MSDCF", &arw),
+		{Number: 100, Name: "100MSDCF", Objects: []*Object{&arw}},
-		wantDirectory(101, "101CANON", &mp4, &thm),
+		{Number: 101, Name: "101CANON", Objects: []*Object{&mp4, &thm}},
 	}
 	if !reflect.DeepEqual(store.Directories, wantDirectories) {
 		t.Errorf("Directories = %+v, want %+v", store.Directories, wantDirectories)
@@ -318,18 +303,19 @@ func TestParseNumberOfFileName(t *testing.T) {
 func TestParseStoreTreatsLowerCaseNamesAsDCFNames(t *testing.T) {
 	t.Parallel()
 
-	card := newCard("DCIM/101abcde/abcd0002.jpg")
+	store := mustParseStore(t, newCard("DCIM/101abcde/abcd0002.jpg"))
 
-	store := mustParseStore(t, card)
+	want := []*Directory{{
-
+		Number: 101,
-	want := []*Directory{wantDirectory(101, "101abcde", &Object{
+		Name:   "101abcde",
-		DCFStoreRoot:    testRoot,
+		Objects: []*Object{{
-		Path:            "DCIM/101abcde/abcd0002.jpg",
+			DCFStoreRoot:    testRoot,
-		Extension:       ".jpg",
+			Path:            "DCIM/101abcde/abcd0002.jpg",
-		DirectoryNumber: 101,
+			Extension:       ".jpg",
-		FileNumber:      2,
+			DirectoryNumber: 101,
-		fsys:            card,
+			FileNumber:      2,
-	})}
+		}},
+	}}
 	if !reflect.DeepEqual(store.Directories, want) {
 		t.Errorf("Directories = %+v, want %+v", store.Directories, want)
 	}
@@ -720,7 +706,7 @@ func TestParseStoreTreatsSymlinksAsMissingDirectories(t *testing.T) {
 }
 
 // failingFS is a card on which one call fails for one path, the way a failing
-// card does. The call is Open, Lstat, ReadDir or Info.
+// card does. The call is Lstat, ReadDir or Info.
 type failingFS struct {
 	fstest.MapFS
 
@@ -728,15 +714,6 @@ type failingFS struct {
 	name string
 }
 
-func (f failingFS) Open(name string) (fs.File, error) {
-	err := f.failure("Open", name)
-	if err != nil {
-		return nil, err
-	}
-
-	return f.MapFS.Open(name)
-}
-
 func (f failingFS) Lstat(name string) (fs.FileInfo, error) {
 	err := f.failure("Lstat", name)
 	if err != nil {
@@ -814,7 +791,7 @@ func TestParseStoreReturnsReadErrorsNamingTheCard(t *testing.T) {
 		for _, name := range names {
 			fsys := failingFS{MapFS: card, call: call, name: name}
 
-			_, err := parseStore(t.Context(), fsys, testRoot)
+			_, err := parseStore(fsys, testRoot)
 			if !errors.Is(err, fs.ErrPermission) {
 				t.Errorf("%s of %s: error = %v, want %v",
 					call, name, err, fs.ErrPermission)
@@ -830,86 +807,3 @@ func TestParseStoreReturnsReadErrorsNamingTheCard(t *testing.T) {
 		}
 	}
 }
-
-// cancelingFS is a card that cancels the read when the read reaches the named
-// directory. It records every directory read in read.
-type cancelingFS struct {
-	fstest.MapFS
-
-	name   string
-	cancel context.CancelFunc
-	read   *[]string
-}
-
-func (f cancelingFS) ReadDir(name string) ([]fs.DirEntry, error) {
-	*f.read = append(*f.read, name)
-
-	if name == f.name {
-		f.cancel()
-	}
-
-	return f.MapFS.ReadDir(name)
-}
-
-func TestParseStoreStopsBeforeTheNextDirectoryWhenCancelled(t *testing.T) {
-	t.Parallel()
-
-	card := newCard(
-		"DCIM/100ABCDE/SUB/README.TXT",
-		"DCIM/OTHER/SUB/README.TXT",
-		"PRIVATE/M4ROOT/CLIP/SUB/C0001.MP4",
-	)
-
-	// Each of these directories holds another directory, which must not be read.
-	names := []string{
-		dcimDirectory,
-		"DCIM/100ABCDE",
-		"DCIM/OTHER",
-		m4RootDirectory,
-		"PRIVATE/M4ROOT/CLIP",
-	}
-
-	for _, name := range names {
-		ctx, cancel := context.WithCancel(t.Context())
-
-		var read []string
-
-		fsys := cancelingFS{MapFS: card, name: name, cancel: cancel, read: &read}
-
-		_, err := parseStore(ctx, fsys, testRoot)
-		if !errors.Is(err, context.Canceled) {
-			t.Errorf("cancelled at %s: error = %v, want %v",
-				name, err, context.Canceled)
-		}
-
-		if read[len(read)-1] != name {
-			t.Errorf("cancelled at %s: read %q", name, read)
-		}
-	}
-}
-
-func TestParseStoreReadsNoDirectoryWhenAlreadyCancelled(t *testing.T) {
-	t.Parallel()
-
-	ctx, cancel := context.WithCancel(t.Context())
-	cancel()
-
-	cards := []fstest.MapFS{
-		newCard("DCIM/README.TXT"),
-		newCard("PRIVATE/M4ROOT/C0001.MP4"),
-	}
-
-	for _, card := range cards {
-		var read []string
-
-		// The context is already cancelled, so this needs no name to cancel at.
-		fsys := cancelingFS{MapFS: card, read: &read}
-
-		_, err := parseStore(ctx, fsys, testRoot)
-		if !errors.Is(err, context.Canceled) {
-			t.Errorf("error = %v, want %v", err, context.Canceled)
-		}
-
-		assertPaths(t, "directories read", read)
-	}
-}