Add more parameter checks and cleaning.

diff --git a/torrent/builder.go b/torrent/builder.go
index 6dd6eb6b8dfad967009f4d188b4ed4b0b69d9b58..97b551e98a7df9e3d5cdf9a878bb34da2c5cabca 100644 (file)
--- a/torrent/builder.go
+++ b/torrent/builder.go
@@ -118,6 +118,12 @@ func (b *Builder) Build(w io.Writer, nworkers int) (<-chan error, <-chan Builder
        status := make(chan BuilderStatus)
 
        go func() {
+               err := b.check_parameters()
+               if err != nil {
+                       completion <- err
+                       return
+               }
+
                b.set_defaults()
                err := b.prepare_files()
                if err != nil {
@@ -380,10 +386,6 @@ func (s file_slice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
 // 3. In case if the 'b.name' was empty, assigns an automatic value to it.
 // 4. Calculates the total size of all the files 'b.files_size'
 func (b *Builder) prepare_files() error {
-       if len(b.filesmap) == 0 {
-               return errors.New("no files were queued")
-       }
-
        const non_regular = os.ModeDir | os.ModeSymlink |
                os.ModeDevice | os.ModeNamedPipe | os.ModeSocket
 
@@ -493,4 +495,42 @@ func (b *Builder) write_torrent(w io.Writer) error {
 
        e := bencode.NewEncoder(w)
        return e.Encode(&td)
+}
+
+func remove_empty_strings(slice []string) []string {
+       j := 0
+       for i, n := 0, len(slice); i < n; i++ {
+               if slice[i] == "" {
+                       continue
+               }
+               slice[j] = slice[i]
+               j++
+       }
+       return slice[:j+1]
+}
+
+func (b *Builder) check_parameters() error {
+       // should be at least one file
+       if len(b.filesmap) == 0 {
+               return errors.New("no files were queued")
+       }
+
+       // let's clean up the announce_list
+       newal := make([][]string, 0, len(b.announce_list))
+       for _, ag := b.announce_list {
+               ag = remove_empty_strings(ag)
+
+               // discard empty announce groups
+               if len(ag) == 0 {
+                       continue
+               }
+               newal = append(newal, ag)
+       }
+       b.announce_list = newal
+       if len(b.announce_list) == 0 {
+               return errors.New("no announce groups were specified")
+       }
+
+       // and clean up the urls
+       b.urls = remove_empty_strings(b.urls)
 }
\ No newline at end of file