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/* XMMS2 - X Music Multiplexer System
* Copyright (C) 2003-2006 XMMS2 Team
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* This file is a part of the XMMS2 client tutorial #3
* Here we will learn to retrieve more complex results from
* the result set
*/
#include <stdlib.h>
/* include xmmsclient header */
#include <xmmsclient/xmmsclient.h>
int
main (int argc, char **argv)
{
/*
* The first part of this program is
* commented on in tut1.c and tut2.c
*/
xmmsc_connection_t *connection;
xmmsc_result_t *result;
xmmsv_t *return_value;
const char *err_buf;
/*
* Variables that we'll need later
*/
const char *val;
int intval;
int id;
xmmsv_t *dict_entry;
xmmsv_t *infos;
connection = xmmsc_init ("tutorial3");
if (!connection) {
fprintf (stderr, "OOM!\n");
exit (EXIT_FAILURE);
}
if (!xmmsc_connect (connection, getenv ("XMMS_PATH"))) {
fprintf (stderr, "Connection failed: %s\n",
xmmsc_get_last_error (connection));
exit (EXIT_FAILURE);
}
/*
* Ok, let' do the same thing as we did in
* tut2.c and retrieve the current playing
* entry. We need that to get information
* about the song.
*/
result = xmmsc_playback_current_id (connection);
xmmsc_result_wait (result);
return_value = xmmsc_result_get_value (result);
if (xmmsv_is_error (return_value) &&
xmmsv_get_error (return_value, &err_buf)) {
fprintf (stderr, "playback current id returns error, %s\n",
err_buf);
}
if (!xmmsv_get_int (return_value, &id)) {
fprintf (stderr, "xmmsc_playback_current_id didn't "
"return int as expected\n");
/* Fake id (ids are >= 1) used as an error flag. */
id = 0;
}
/* Print the value */
printf ("Currently playing id is %d\n", id);
/*
* Same drill as before. Release memory
* so that we can reuse it in the next
* clientlib call.
* */
xmmsc_result_unref (result);
/*
* Something about the medialib and xmms2. All
* entries that are played, put into playlists
* have to be in the medialib. A song's metadata
* will be added to the medialib the first time
* you do "xmms2 add" or equivalent.
*
* When we request information for an entry, it will
* be requested from the medialib, not the playlist
* or the playback. The playlist and playback only
* know the unique id of the entry. All other
* information must be retrieved in subsequent calls.
*
* Entry 0 is non valid. Only 1-inf is valid.
* So let's check for 0 and don't ask medialib for it.
*/
if (id == 0) {
fprintf (stderr, "Nothing is playing.\n");
exit (EXIT_FAILURE);
}
/*
* And now for something about return types from
* clientlib. The clientlib will always return
* an xmmsc_result_t that will eventually contain the
* return value as a xmmsv_t struct.
* The value can contain an int and string as
* base type. It can also contain more complex
* types like lists and dicts.
* A list is a sequence of values, each of them
* wrapped in its own xmmsv_t struct (of any type).
* A dict is a key<->value representation where key
* is always a string but the value is again wrapped
* in its own xmmsv_t struct (of any type).
*
* When retrieving an entry from the medialib, you
* get a dict as return. Let's print out some
* entries from it and then traverse the dict.
*/
result = xmmsc_medialib_get_info (connection, id);
/* And waaait for it .. */
xmmsc_result_wait (result);
/* Let's reuse the previous return_value pointer, it
* was invalidated as soon as we freed the result that
* contained it anyway.
*/
return_value = xmmsc_result_get_value (result);
if (xmmsv_is_error (return_value) &&
xmmsv_get_error (return_value, &err_buf)) {
/*
* This can return error if the id
* is not in the medialib
*/
fprintf (stderr, "medialib get info returns error, %s\n",
err_buf);
exit (EXIT_FAILURE);
}
/*
* Because of the nature of the dict returned by
* xmmsc_medialib_get_info, we need to convert it to
* a simpler dict using xmmsv_propdict_to_dict.
* Let's not worry about that for now and accept it
* as a fact of life.
*
* See tut5 for a discussion about dicts and propdicts.
*
* Note that xmmsv_propdict_to_dict creates a new
* xmmsv_t struct, which we will need to free manually
* when we're done with it.
*/
infos = xmmsv_propdict_to_dict (return_value, NULL);
/*
* We must first retrieve the xmmsv_t struct
* corresponding to the "artist" key in the dict,
* and then extract the string from that struct.
*/
if (!xmmsv_dict_get (infos, "artist", &dict_entry) ||
!xmmsv_get_string (dict_entry, &val)) {
/*
* if we end up here it means that the key "artist" wasn't
* in the dict or that the value for "artist" wasn't a
* string.
*
* You can check the type of the entry (if there is one) with
* xmmsv_get_type (dict_entry). It will return an
* xmmsv_type_t enum describing the type.
*
* Actually this is no disaster, it might just mean that
* we don't have an artist tag on this entry. Let's
* call it "No Artist" for now.
*/
val = "No Artist";
}
/* print the value */
printf ("artist = %s\n", val);
if (!xmmsv_dict_get (infos, "title", &dict_entry) ||
!xmmsv_get_string (dict_entry, &val)) {
val = "No Title";
}
printf ("title = %s\n", val);
/*
* Let's extract an integer as well
*/
if (!xmmsv_dict_get (infos, "bitrate", &dict_entry) ||
!xmmsv_get_int (dict_entry, &intval)) {
intval = 0;
}
printf ("bitrate = %i\n", intval);
/*
* We need to free infos manually here, else we will leak.
*/
xmmsv_unref (infos);
/*
* !!Important!!
*
* When unreffing the result here we will free
* the memory that we have extracted from the dict,
* and that includes all the string pointers of the
* dict entries! So if you want to keep strings
* somewhere you need to copy that memory! Very
* important otherwise you will get undefined behaviour.
*/
xmmsc_result_unref (result);
xmmsc_unref (connection);
return (EXIT_SUCCESS);
}
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