From 4de12bf59312ce47315f8c769fab9cfcd4c83b0b Mon Sep 17 00:00:00 2001
From: greatroar <@>
Date: Mon, 9 Mar 2020 09:54:24 +0100
Subject: [PATCH] Remove restic.RandReader

math/rand.Rand has implemented Reader since Go 1.6. The repacking tests
are not deterministic, but they weren't before, either.
---
 internal/repository/repack_test.go | 15 +-----
 internal/restic/rand_reader.go     | 81 ------------------------------
 internal/restic/testing.go         |  2 +-
 3 files changed, 3 insertions(+), 95 deletions(-)
 delete mode 100644 internal/restic/rand_reader.go

diff --git a/internal/repository/repack_test.go b/internal/repository/repack_test.go
index 286962f49..84955ec30 100644
--- a/internal/repository/repack_test.go
+++ b/internal/repository/repack_test.go
@@ -2,7 +2,6 @@ package repository_test
 
 import (
 	"context"
-	"io"
 	"math/rand"
 	"testing"
 
@@ -15,17 +14,6 @@ func randomSize(min, max int) int {
 	return rand.Intn(max-min) + min
 }
 
-func random(t testing.TB, length int) []byte {
-	rd := restic.NewRandReader(rand.New(rand.NewSource(rand.Int63())))
-	buf := make([]byte, length)
-	_, err := io.ReadFull(rd, buf)
-	if err != nil {
-		t.Fatalf("unable to read %d random bytes: %v", length, err)
-	}
-
-	return buf
-}
-
 func createRandomBlobs(t testing.TB, repo restic.Repository, blobs int, pData float32) {
 	for i := 0; i < blobs; i++ {
 		var (
@@ -41,7 +29,8 @@ func createRandomBlobs(t testing.TB, repo restic.Repository, blobs int, pData fl
 			length = randomSize(1*1024, 20*1024) // 1KiB to 20KiB
 		}
 
-		buf := random(t, length)
+		buf := make([]byte, length)
+		rand.Read(buf)
 		id := restic.Hash(buf)
 
 		if repo.Index().Has(id, restic.DataBlob) {
diff --git a/internal/restic/rand_reader.go b/internal/restic/rand_reader.go
deleted file mode 100644
index b5bc83839..000000000
--- a/internal/restic/rand_reader.go
+++ /dev/null
@@ -1,81 +0,0 @@
-package restic
-
-import (
-	"io"
-	"math/rand"
-
-	"github.com/restic/restic/internal/errors"
-)
-
-// RandReader allows reading from a rand.Rand.
-type RandReader struct {
-	rnd *rand.Rand
-	buf []byte
-}
-
-// NewRandReader creates a new Reader from a random source.
-func NewRandReader(rnd *rand.Rand) io.Reader {
-	return &RandReader{rnd: rnd, buf: make([]byte, 0, 7)}
-}
-
-func (rd *RandReader) read(p []byte) (n int, err error) {
-	if len(p)%7 != 0 {
-		panic("invalid buffer length, not multiple of 7")
-	}
-
-	rnd := rd.rnd
-	for i := 0; i < len(p); i += 7 {
-		val := rnd.Int63()
-
-		p[i+0] = byte(val >> 0)
-		p[i+1] = byte(val >> 8)
-		p[i+2] = byte(val >> 16)
-		p[i+3] = byte(val >> 24)
-		p[i+4] = byte(val >> 32)
-		p[i+5] = byte(val >> 40)
-		p[i+6] = byte(val >> 48)
-	}
-
-	return len(p), nil
-}
-
-func (rd *RandReader) Read(p []byte) (int, error) {
-	// first, copy buffer to p
-	pos := copy(p, rd.buf)
-	copy(rd.buf, rd.buf[pos:])
-
-	// shorten buf and p accordingly
-	rd.buf = rd.buf[:len(rd.buf)-pos]
-	p = p[pos:]
-
-	// if this is enough to fill p, return
-	if len(p) == 0 {
-		return pos, nil
-	}
-
-	// load multiple of 7 byte
-	l := (len(p) / 7) * 7
-	n, err := rd.read(p[:l])
-	pos += n
-	if err != nil {
-		return pos, errors.Wrap(err, "Read")
-	}
-	p = p[n:]
-
-	// load 7 byte to temp buffer
-	rd.buf = rd.buf[:7]
-	n, err = rd.read(rd.buf)
-	if err != nil {
-		return pos, errors.Wrap(err, "Read")
-	}
-
-	// copy the remaining bytes from the buffer to p
-	n = copy(p, rd.buf)
-	pos += n
-
-	// save the remaining bytes in rd.buf
-	n = copy(rd.buf, rd.buf[n:])
-	rd.buf = rd.buf[:n]
-
-	return pos, nil
-}
diff --git a/internal/restic/testing.go b/internal/restic/testing.go
index eb10919e7..0cf7d171a 100644
--- a/internal/restic/testing.go
+++ b/internal/restic/testing.go
@@ -16,7 +16,7 @@ import (
 
 // fakeFile returns a reader which yields deterministic pseudo-random data.
 func fakeFile(t testing.TB, seed, size int64) io.Reader {
-	return io.LimitReader(NewRandReader(rand.New(rand.NewSource(seed))), size)
+	return io.LimitReader(rand.New(rand.NewSource(seed)), size)
 }
 
 type fakeFileSystem struct {