overdue

.rclone_repo/cmd/mount/test/seeker.go

@@ -0,0 +1,115 @@
+// +build ignore
+
+// Read two files with lots of seeking to stress test the seek code
+package main
+
+import (
+	"bytes"
+	"flag"
+	"io"
+	"io/ioutil"
+	"log"
+	"math/rand"
+	"os"
+	"time"
+)
+
+var (
+	// Flags
+	iterations   = flag.Int("n", 1E6, "Iterations to try")
+	maxBlockSize = flag.Int("b", 1024*1024, "Max block size to read")
+)
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+func randomSeekTest(size int64, in1, in2 *os.File, file1, file2 string) {
+	start := rand.Int63n(size)
+	blockSize := rand.Intn(*maxBlockSize)
+	if int64(blockSize) > size-start {
+		blockSize = int(size - start)
+	}
+	log.Printf("Reading %d from %d", blockSize, start)
+
+	_, err := in1.Seek(start, io.SeekStart)
+	if err != nil {
+		log.Fatalf("Seek failed on %q: %v", file1, err)
+	}
+	_, err = in2.Seek(start, io.SeekStart)
+	if err != nil {
+		log.Fatalf("Seek failed on %q: %v", file2, err)
+	}
+
+	buf1 := make([]byte, blockSize)
+	n1, err := io.ReadFull(in1, buf1)
+	if err != nil {
+		log.Fatalf("Read failed on %q: %v", file1, err)
+	}
+
+	buf2 := make([]byte, blockSize)
+	n2, err := io.ReadFull(in2, buf2)
+	if err != nil {
+		log.Fatalf("Read failed on %q: %v", file2, err)
+	}
+
+	if n1 != n2 {
+		log.Fatalf("Read different lengths %d (%q) != %d (%q)", n1, file1, n2, file2)
+	}
+
+	if !bytes.Equal(buf1, buf2) {
+		log.Printf("Dumping different blocks")
+		err = ioutil.WriteFile("/tmp/z1", buf1, 0777)
+		if err != nil {
+			log.Fatalf("Failed to write /tmp/z1: %v", err)
+		}
+		err = ioutil.WriteFile("/tmp/z2", buf2, 0777)
+		if err != nil {
+			log.Fatalf("Failed to write /tmp/z2: %v", err)
+		}
+		log.Fatalf("Read different contents - saved in /tmp/z1 and /tmp/z2")
+	}
+}
+
+func main() {
+	flag.Parse()
+	args := flag.Args()
+	if len(args) != 2 {
+		log.Fatalf("Require 2 files as argument")
+	}
+	file1, file2 := args[0], args[1]
+	in1, err := os.Open(file1)
+	if err != nil {
+		log.Fatalf("Couldn't open %q: %v", file1, err)
+	}
+	in2, err := os.Open(file2)
+	if err != nil {
+		log.Fatalf("Couldn't open %q: %v", file2, err)
+	}
+
+	fi1, err := in1.Stat()
+	if err != nil {
+		log.Fatalf("Couldn't stat %q: %v", file1, err)
+	}
+	fi2, err := in2.Stat()
+	if err != nil {
+		log.Fatalf("Couldn't stat %q: %v", file2, err)
+	}
+
+	if fi1.Size() != fi2.Size() {
+		log.Fatalf("Files not the same size")
+	}
+
+	for i := 0; i < *iterations; i++ {
+		randomSeekTest(fi1.Size(), in1, in2, file1, file2)
+	}
+
+	err = in1.Close()
+	if err != nil {
+		log.Fatalf("Error closing %q: %v", file1, err)
+	}
+	err = in2.Close()
+	if err != nil {
+		log.Fatalf("Error closing %q: %v", file2, err)
+	}
+}