stream: don't require streams to set s->pos in seek callback

Instead, set s->pos depending on the success of the seek callback.

stream/stream.c

@@ -550,6 +550,7 @@ static int stream_seek_unbuffered(stream_t *s, int64_t newpos)
             return 0;
         }
     }
+    s->pos = newpos;
     s->eof = 0; // EOF reset when seek succeeds.
     return -1;
 }
@@ -558,7 +559,6 @@ static int stream_seek_unbuffered(stream_t *s, int64_t newpos)
 // Unlike stream_seek_unbuffered(), it still fills the local buffer.
 static int stream_seek_long(stream_t *s, int64_t pos)
 {
-    int64_t oldpos = s->pos;
     s->buf_pos = s->buf_len = 0;
     s->eof = 0;
 
@@ -572,14 +572,12 @@ static int stream_seek_long(stream_t *s, int64_t pos)
     if (s->sector_size)
         newpos = (pos / s->sector_size) * s->sector_size;
 
-    mp_msg(MSGT_STREAM, MSGL_DBG3, "s->pos=%" PRIX64 "  newpos=%" PRIX64
-           "  new_bufpos=%" PRIX64 "  buflen=%X  \n",
-           (int64_t)s->pos, (int64_t)newpos, (int64_t)pos, s->buf_len);
+    mp_msg(MSGT_STREAM, MSGL_DBG3, "Seek from %" PRId64 " to %" PRId64
+           " (with offset %d)\n", s->pos, pos, (int)(pos - newpos));
 
     if (!s->seek && (s->flags & MP_STREAM_FAST_SKIPPING) && pos >= s->pos) {
         // skipping is handled by generic code below
     } else if (stream_seek_unbuffered(s, newpos) >= 0) {
-        s->pos = oldpos;
         return 0;
     }
 

stream/stream_bluray.c

@@ -92,7 +92,6 @@ static int bluray_stream_seek(stream_t *s, int64_t pos)
     if (p == -1)
         return 0;
 
-    s->pos = p;
     return 1;
 }
 

stream/stream_cdda.c

@@ -213,9 +213,8 @@ static int seek(stream_t *s, int64_t newpos)
     int seek_to_track = 0;
     int i;
 
-    s->pos = newpos;
-    sec = s->pos / CDIO_CD_FRAMESIZE_RAW;
-    if (s->pos < 0 || sec > p->end_sector) {
+    sec = newpos / CDIO_CD_FRAMESIZE_RAW;
+    if (newpos < 0 || sec > p->end_sector) {
         p->sector = p->end_sector + 1;
         return 0;
     }

stream/stream_dvd.c

@@ -354,13 +354,13 @@ static int fill_buffer(stream_t *s, char *buf, int len)
   pos = dvd_read_sector(s->priv, buf);
   if (pos < 0)
     return -1;
+  // dvd_read_sector() sometimes internally skips disk-level blocks
   s->pos = 2048*(pos - 1);
   return 2048; // full sector
 }
 
 static int seek(stream_t *s, int64_t newpos) {
-  s->pos=newpos; // real seek
-  dvd_seek(s->priv,s->pos/2048);
+  dvd_seek(s->priv,newpos/2048);
   return 1;
 }
 

stream/stream_file.c

@@ -63,10 +63,7 @@ static int write_buffer(stream_t *s, char *buffer, int len)
 static int seek(stream_t *s, int64_t newpos)
 {
     struct priv *p = s->priv;
-    s->pos = newpos;
-    if (lseek(p->fd, s->pos, SEEK_SET) < 0)
-        return 0;
-    return 1;
+    return lseek(p->fd, newpos, SEEK_SET) != (off_t)-1;
 }
 
 static int control(stream_t *s, int cmd, void *arg)

stream/stream_lavf.c

@@ -60,8 +60,7 @@ static int seek(stream_t *s, int64_t newpos)
     AVIOContext *avio = s->priv;
     if (!avio)
         return -1;
-    s->pos = newpos;
-    if (avio_seek(avio, s->pos, SEEK_SET) < 0) {
+    if (avio_seek(avio, newpos, SEEK_SET) < 0) {
         return 0;
     }
     return 1;

stream/stream_memory.c

@@ -36,7 +36,6 @@ static int fill_buffer(stream_t *s, char* buffer, int len)
 
 static int seek(stream_t *s, int64_t newpos)
 {
-    s->pos = newpos;
     return 1;
 }
 

stream/stream_smb.c

@@ -76,8 +76,7 @@ static int control(stream_t *s, int cmd, void *arg) {
 
 static int seek(stream_t *s,int64_t newpos) {
   struct priv *p = s->priv;
-  s->pos = newpos;
-  if(smbc_lseek(p->fd,s->pos,SEEK_SET)<0) {
+  if(smbc_lseek(p->fd,newpos,SEEK_SET)<0) {
     return 0;
   }
   return 1;

stream/stream_vcd.c

@@ -67,8 +67,7 @@ static int fill_buffer(stream_t *s, char* buffer, int max_len){
 }
 
 static int seek(stream_t *s,int64_t newpos) {
-  s->pos = newpos;
-  vcd_set_msf(s->priv,s->pos/VCD_SECTOR_DATA);
+  vcd_set_msf(s->priv,newpos/VCD_SECTOR_DATA);
   return 1;
 }