check: refactor pack selection for read data

Drop the `packs` map from the internal state of the checker. Instead the Packs(...) method now calls a filter callback that can select the packs intended for checking.
2026-05-13 14:05:24 +00:00 · 2025-10-03 22:46:43 +02:00
parent 3ae6a69154
commit b7bbb408ee
5 changed files with 96 additions and 78 deletions
@@ -230,6 +230,11 @@ func runCheck(ctx context.Context, opts CheckOptions, gopts GlobalOptions, args
 		printer = newJSONErrorPrinter(term)
 	}

+	readDataFilter, err := buildPacksFilter(opts, printer)
+	if err != nil {
+		return summary, err
+	}
+
 	cleanup := prepareCheckCache(opts, &gopts, printer)
 	defer cleanup()

@@ -370,12 +375,11 @@ func runCheck(ctx context.Context, opts CheckOptions, gopts GlobalOptions, args
 		}
 	}

-	doReadData := func(packs map[restic.ID]int64) {
+	if readDataFilter != nil {
 		p := printer.NewCounter("packs")
-		p.SetMax(uint64(len(packs)))
 		errChan := make(chan error)

-		go chkr.ReadPacks(ctx, packs, p, errChan)
+		go chkr.ReadPacks(ctx, readDataFilter, p, errChan)

 		for err := range errChan {
 			errorsFound = true
@@ -388,48 +392,6 @@ func runCheck(ctx context.Context, opts CheckOptions, gopts GlobalOptions, args
 		p.Done()
 	}

-	switch {
-	case opts.ReadData:
-		printer.P("read all data\n")
-		doReadData(selectPacksByBucket(chkr.GetPacks(), 1, 1))
-	case opts.ReadDataSubset != "":
-		var packs map[restic.ID]int64
-		dataSubset, err := stringToIntSlice(opts.ReadDataSubset)
-		if err == nil {
-			bucket := dataSubset[0]
-			totalBuckets := dataSubset[1]
-			packs = selectPacksByBucket(chkr.GetPacks(), bucket, totalBuckets)
-			packCount := uint64(len(packs))
-			printer.P("read group #%d of %d data packs (out of total %d packs in %d groups)\n", bucket, packCount, chkr.CountPacks(), totalBuckets)
-		} else if strings.HasSuffix(opts.ReadDataSubset, "%") {
-			percentage, err := parsePercentage(opts.ReadDataSubset)
-			if err == nil {
-				packs = selectRandomPacksByPercentage(chkr.GetPacks(), percentage)
-				printer.P("read %.1f%% of data packs\n", percentage)
-			}
-		} else {
-			repoSize := int64(0)
-			allPacks := chkr.GetPacks()
-			for _, size := range allPacks {
-				repoSize += size
-			}
-			if repoSize == 0 {
-				return summary, errors.Fatal("Cannot read from a repository having size 0")
-			}
-			subsetSize, _ := ui.ParseBytes(opts.ReadDataSubset)
-			if subsetSize > repoSize {
-				subsetSize = repoSize
-			}
-			packs = selectRandomPacksByFileSize(chkr.GetPacks(), subsetSize, repoSize)
-			percentage := float64(subsetSize) / float64(repoSize) * 100.0
-			printer.P("read %d bytes (%.1f%%) of data packs\n", subsetSize, percentage)
-		}
-		if packs == nil {
-			return summary, errors.Fatal("internal error: failed to select packs to check")
-		}
-		doReadData(packs)
-	}
-
 	if len(salvagePacks) > 0 {
 		printer.E("\nThe repository contains damaged pack files. These damaged files must be removed to repair the repository. This can be done using the following commands. Please read the troubleshooting guide at https://restic.readthedocs.io/en/stable/077_troubleshooting.html first.\n\n")
 		for id := range salvagePacks {
@@ -453,6 +415,59 @@ func runCheck(ctx context.Context, opts CheckOptions, gopts GlobalOptions, args
 	return summary, nil
 }

+func buildPacksFilter(opts CheckOptions, printer progress.Printer) (func(packs map[restic.ID]int64) map[restic.ID]int64, error) {
+	switch {
+	case opts.ReadData:
+		return func(packs map[restic.ID]int64) map[restic.ID]int64 {
+			printer.P("read all data\n")
+			return packs
+		}, nil
+	case opts.ReadDataSubset != "":
+		dataSubset, err := stringToIntSlice(opts.ReadDataSubset)
+		if err == nil {
+			bucket := dataSubset[0]
+			totalBuckets := dataSubset[1]
+			return func(packs map[restic.ID]int64) map[restic.ID]int64 {
+				packCount := uint64(len(packs))
+				packs = selectPacksByBucket(packs, bucket, totalBuckets)
+				printer.P("read group #%d of %d data packs (out of total %d packs in %d groups)\n", bucket, len(packs), packCount, totalBuckets)
+				return packs
+			}, nil
+		} else if strings.HasSuffix(opts.ReadDataSubset, "%") {
+			percentage, err := parsePercentage(opts.ReadDataSubset)
+			if err != nil {
+				return nil, err
+			}
+			return func(packs map[restic.ID]int64) map[restic.ID]int64 {
+				printer.P("read %.1f%% of data packs\n", percentage)
+				return selectRandomPacksByPercentage(packs, percentage)
+			}, nil
+		}
+
+		repoSize := int64(0)
+		return func(packs map[restic.ID]int64) map[restic.ID]int64 {
+			for _, size := range packs {
+				repoSize += size
+			}
+			subsetSize, _ := ui.ParseBytes(opts.ReadDataSubset)
+			if subsetSize > repoSize {
+				subsetSize = repoSize
+			}
+			if repoSize > 0 {
+				packs = selectRandomPacksByFileSize(packs, subsetSize, repoSize)
+			}
+			percentage := float64(subsetSize) / float64(repoSize) * 100.0
+			if repoSize == 0 {
+				percentage = 100
+			}
+			printer.P("read %d bytes (%.1f%%) of data packs\n", subsetSize, percentage)
+			return packs
+		}, nil
+	}
+
+	return nil, nil
+}
+
 // selectPacksByBucket selects subsets of packs by ranges of buckets.
 func selectPacksByBucket(allPacks map[restic.ID]int64, bucket, totalBuckets uint) map[restic.ID]int64 {
 	packs := make(map[restic.ID]int64)