Fix reading of CDDB information (ref. cset a470c338149c)

This fixes the reading of CDDB information by not setting INPUT_CAP_BLOCK
for the CDDA plugin (and therefore also setting CD_RAW_FRAME_SIZE to 0), and
allow reading in non-block sized chunks as per
http://hg.debian.org/hg/xine-lib/xine-lib?cmd=changeset;node=a470c338149c;style=gitweb

Explanation: At some point a number of releases ago, a codepath in Xine
related to the reading of block devices which had been bypassed was fixed,
which meant that when certain frontends asked Xine to provide CDDB
information for a disc, querying the name, length, etc.  of each track, Xine
would actually cause a seek to the starting block of each track, which meant
that before starting to play, the player would pause for 5-10 seconds,
seeking through each track.  This is unnecessary, since Xine should have
simply used the CD TOC information from the CD audio header at the start of
the disc.  Other frontends handle CDDB differently and don't query Xine for
information track by track, and so never triggered this problem.  But for
those with the problem, it made loading a disc rather slow.

It turns out that the root of the problem is that the CDDA plugin shouldn't
be setting INPUT_CAP_BLOCK, since Audio CDs are not block devices _in the
sense that Xine intends_.  Simply turning this off fixes the problem, with
no other side effects (tested locally, for some time now, on xine-ui, kscd,
kaffeine, amarok, etc.).

This change pairs nicely with a patch originally committed years ago (cset
a470c338149c) but which was reverted as it inadvertently triggered the same
problem as is now (properly) fixed by the simple above-mentioned change.
Now that a better fix is in, it can be re-committed.

1 files changed, 20 insertions, 16 deletions

diff --git a/src/input/input_cdda.c b/src/input/input_cdda.c
index 33ba0b299..70bd34f35 100644
--- a/src/input/input_cdda.c
+++ b/src/input/input_cdda.c
@@ -2158,26 +2158,18 @@ static int cdda_close(cdda_input_plugin_t *this_gen) {
 
 static uint32_t cdda_plugin_get_capabilities (input_plugin_t *this_gen) {
 
-  return INPUT_CAP_SEEKABLE | INPUT_CAP_BLOCK;
+  return INPUT_CAP_SEEKABLE;
 }
 
 
 static off_t cdda_plugin_read (input_plugin_t *this_gen, char *buf, off_t len) {
 
-  /* only allow reading in block-sized chunks */
-
-  return 0;
-}
-
-static buf_element_t *cdda_plugin_read_block (input_plugin_t *this_gen, fifo_buffer_t *fifo, 
-  off_t nlen) {
-
   cdda_input_plugin_t *this = (cdda_input_plugin_t *) this_gen;
-  buf_element_t *buf;
-  unsigned char frame_data[CD_RAW_FRAME_SIZE];
   int err = 0;
 
-  if (nlen != CD_RAW_FRAME_SIZE)
+  /* only allow reading in block-sized chunks */
+
+  if (len != CD_RAW_FRAME_SIZE)
     return 0;
 
   if (this->current_frame > this->last_frame)
@@ -2211,14 +2203,26 @@ static buf_element_t *cdda_plugin_read_block (input_plugin_t *this_gen, fifo_buf
   if( err < 0 )
     return 0;
     
-  memcpy(frame_data, this->cache[this->current_frame-this->cache_first], CD_RAW_FRAME_SIZE);
+  memcpy(buf, this->cache[this->current_frame-this->cache_first], CD_RAW_FRAME_SIZE);
   this->current_frame++;
 
+  return CD_RAW_FRAME_SIZE;
+}
+
+static buf_element_t *cdda_plugin_read_block (input_plugin_t *this_gen, fifo_buffer_t *fifo,
+  off_t nlen) {
+
+  buf_element_t *buf;
+
   buf = fifo->buffer_pool_alloc(fifo);
   buf->content = buf->mem;
   buf->type = BUF_DEMUX_BLOCK;
-  buf->size = CD_RAW_FRAME_SIZE;
-  memcpy(buf->mem, frame_data, CD_RAW_FRAME_SIZE);
+
+  buf->size = cdda_plugin_read(this_gen, buf->content, nlen);
+  if (buf->size == 0) {
+    buf->free_buffer(buf);
+    buf = NULL;
+  }
 
   return buf;
 }
@@ -2256,7 +2260,7 @@ static off_t cdda_plugin_get_length (input_plugin_t *this_gen) {
 
 static uint32_t cdda_plugin_get_blocksize (input_plugin_t *this_gen) {
 
-  return CD_RAW_FRAME_SIZE;
+  return 0;
 }
 
 static const char* cdda_plugin_get_mrl (input_plugin_t *this_gen) {