test makefiles: add --sparse, --zero, --pattern and --ascii flags

cmd/test/makefiles/makefiles.go

@@ -5,6 +5,7 @@ package makefiles
 import (
 	"io"
 	"log"
+	"math"
 	"math/rand"
 	"os"
 	"path/filepath"
@@ -16,6 +17,7 @@ import (
 	"github.com/rclone/rclone/fs/config/flags"
 	"github.com/rclone/rclone/lib/file"
 	"github.com/rclone/rclone/lib/random"
+	"github.com/rclone/rclone/lib/readers"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 )
@@ -30,9 +32,14 @@ var (
 	minFileNameLength        = 4
 	maxFileNameLength        = 12
 	seed                     = int64(1)
+	zero                     = false
+	sparse                   = false
+	ascii                    = false
+	pattern                  = false
 
 	// Globals
 	randSource          *rand.Rand
+	source              io.Reader
 	directoriesToCreate int
 	totalDirectories    int
 	fileNames           = map[string]struct{}{} // keep a note of which file name we've used already
@@ -55,18 +62,13 @@ func init() {
 	// Common flags to makefiles and makefile
 	for _, f := range []*pflag.FlagSet{makefilesFlags, makefileFlags} {
 		flags.Int64VarP(f, &seed, "seed", "", seed, "Seed for the random number generator (0 for random)")
+		flags.BoolVarP(f, &zero, "zero", "", zero, "Fill files with ASCII 0x00")
+		flags.BoolVarP(f, &sparse, "sparse", "", sparse, "Make the files sparse (appear to be filled with ASCII 0x00)")
+		flags.BoolVarP(f, &ascii, "ascii", "", ascii, "Fill files with random ASCII printable bytes only")
+		flags.BoolVarP(f, &pattern, "pattern", "", ascii, "Fill files with a periodic pattern")
 	}
 }
 
-// common initialisation for makefiles and makefile
-func commonInit() {
-	if seed == 0 {
-		seed = time.Now().UnixNano()
-		fs.Logf(nil, "Using random seed = %d", seed)
-	}
-	randSource = rand.New(rand.NewSource(seed))
-}
-
 var makefilesCmd = &cobra.Command{
 	Use:   "makefiles <dir>",
 	Short: `Make a random file hierarchy in a directory`,
@@ -96,7 +98,7 @@ var makefilesCmd = &cobra.Command{
 }
 
 var makefileCmd = &cobra.Command{
-	Use:   "makefile <size> [<file>]+",
+	Use:   "makefile <size> [<file>]+ [flags]",
 	Short: `Make files with random contents of the size given`,
 	Run: func(command *cobra.Command, args []string) {
 		cmd.CheckArgs(1, 1e6, command, args)
@@ -120,6 +122,56 @@ var makefileCmd = &cobra.Command{
 	},
 }
 
+func bool2int(b bool) int {
+	if b {
+		return 1
+	}
+	return 0
+}
+
+// common initialisation for makefiles and makefile
+func commonInit() {
+	if seed == 0 {
+		seed = time.Now().UnixNano()
+		fs.Logf(nil, "Using random seed = %d", seed)
+	}
+	randSource = rand.New(rand.NewSource(seed))
+	if bool2int(zero)+bool2int(sparse)+bool2int(ascii)+bool2int(pattern) > 1 {
+		log.Fatal("Can only supply one of --zero, --sparse, --ascii or --pattern")
+	}
+	switch {
+	case zero, sparse:
+		source = zeroReader{}
+	case ascii:
+		source = asciiReader{}
+	case pattern:
+		source = readers.NewPatternReader(math.MaxInt64)
+	default:
+		source = randSource
+	}
+}
+
+type zeroReader struct{}
+
+// Read a chunk of zeroes
+func (zeroReader) Read(p []byte) (n int, err error) {
+	for i := range p {
+		p[i] = 0
+	}
+	return len(p), nil
+}
+
+type asciiReader struct{}
+
+// Read a chunk of printable ASCII characters
+func (asciiReader) Read(p []byte) (n int, err error) {
+	n, err = randSource.Read(p)
+	for i := range p[:n] {
+		p[i] = (p[i] % (0x7F - 0x20)) + 0x20
+	}
+	return n, err
+}
+
 // fileName creates a unique random file or directory name
 func fileName() (name string) {
 	for {
@@ -184,7 +236,11 @@ func writeFile(dir, name string, size int64) {
 	if err != nil {
 		log.Fatalf("Failed to open file %q: %v", path, err)
 	}
-	_, err = io.CopyN(fd, randSource, size)
+	if sparse {
+		err = fd.Truncate(size)
+	} else {
+		_, err = io.CopyN(fd, source, size)
+	}
 	if err != nil {
 		log.Fatalf("Failed to write %v bytes to file %q: %v", size, path, err)
 	}