Fixed download helper bug

1) Modified fileutil.go to return a status message.
2) Removed all  log.fatal

downloadhelper/fileutil.go

@@ -6,7 +6,7 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"log"
+
 	"os"
 	"strconv"
 	"strings"
@@ -16,13 +16,13 @@ import (
 func createTempFile(partFilename string, fileBegin, fileEnd int) {
 	buf := new(bytes.Buffer)
 	if err := binary.Write(buf, binary.LittleEndian, int64(fileBegin)); err != nil {
-		log.Fatal(err)
+		panic(err)
 	}
 	if err := binary.Write(buf, binary.LittleEndian, int64(fileEnd)); err != nil {
-		log.Fatal(err)
+		panic(err)
 	}
 	if err := ioutil.WriteFile(partFilename, buf.Bytes(), 0666); err != nil {
-		log.Fatal(err)
+		panic(err)
 	}
 }
 
@@ -47,7 +47,7 @@ func writeBytes(partFilename string, reader []byte, byteStart, byteEnd int) erro
 func readHeader(partFilename string) (int, int) {
 	reader, err := ioutil.ReadFile(partFilename)
 	if err != nil {
-		log.Fatal(err)
+		panic(err)
 	}
 	header := reader[:16]
 	byteStart := int(binary.LittleEndian.Uint64(header[0:8])) + len(reader) - 16
@@ -63,20 +63,20 @@ func mergeFiles(filename string, count int) {
 
 	file, err := os.OpenFile(DownloadLocation+"/"+tempFilename, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
 	if err != nil {
-		log.Fatal(err)
+		panic(err)
 	}
 	defer file.Close()
 
 	for i := 0; i < count; i++ {
 		partFilename := DownloadLocation + "/temp/" + filename + "_" + strconv.Itoa(i)
-		
+
 		reader, err := ioutil.ReadFile(partFilename)
 		reader = reader[16:]
 		if err != nil {
-			log.Fatal(err)
+			panic(err)
 		}
 		if _, err = file.WriteString(string(reader)); err != nil {
-			log.Fatal(err)
+			panic(err)
 		}
 	}
 	file.Close()
@@ -102,7 +102,7 @@ func clearFiles(filename string, count int) {
 	}
 	empty, err := isDirEmpty(DownloadLocation + "/temp/")
 	if err != nil {
-		log.Fatal(err)
+		panic(err)
 	}
 	if empty {
 		os.Remove(DownloadLocation + "/temp/")
@@ -112,20 +112,21 @@ func clearFiles(filename string, count int) {
 func noOfExistingConnection(filename string, length int) int {
 	existingFilename := DownloadLocation + "/temp/" + filename + "_0"
 	if _, err := os.Stat(existingFilename); err != nil {
-		log.Fatal("No file to resume downloading")
+		return 0
+		// panic("No file to resume downloading 1")
 	}
 	if _, err := os.Stat(existingFilename); err == nil {
 		reader, err := ioutil.ReadFile(existingFilename)
 		if err != nil {
-			log.Fatal(err)
+			panic(err)
 		}
 		if len(reader) < 16 {
-			log.Fatal("No file to resume downloading")
+			panic("No file to resume downloading 2")
 		}
 		header := reader[:16]
 		interval := int(binary.LittleEndian.Uint64(header[8:16])) - int(binary.LittleEndian.Uint64(header[0:8]))
 		if interval == 0 {
-			log.Fatal("No file to resume downloading")
+			panic("No file to resume downloading 3")
 		}
 		return (length / interval)
 	}