Commit bc2a1160 authored by Max Kellermann's avatar Max Kellermann

db/Count: implement grouping

parent 75542e8f
......@@ -6,7 +6,7 @@ ver 0.19 (not yet released)
- "playlistadd" supports file:///
- "idle" with unrecognized event name fails
- "list" on album artist falls back to the artist tag
- "list" allows grouping
- "list" and "count" allow grouping
* database
- proxy: forward "idle" events
- proxy: copy "Last-Modified" from remote directories
......
......@@ -1493,12 +1493,15 @@ OK
<title>The music database</title>
<variablelist>
<varlistentry id="command_count">
<term>
<cmdsynopsis>
<command>count</command>
<arg choice="req"><replaceable>TAG</replaceable></arg>
<arg choice="req"><replaceable>NEEDLE</replaceable></arg>
<arg choice="opt">group</arg>
<arg choice="opt"><replaceable>GROUPTYPE</replaceable></arg>
</cmdsynopsis>
</term>
<listitem>
......@@ -1506,8 +1509,15 @@ OK
Counts the number of songs and their total playtime in
the db matching <varname>TAG</varname> exactly.
</para>
<para>
The <parameter>group</parameter> keyword may be used to
group the results by a tag. The following prints
per-artist counts:
</para>
<programlisting>count group artist</programlisting>
</listitem>
</varlistentry>
<varlistentry id="command_find">
<term>
<cmdsynopsis>
......
......@@ -153,14 +153,28 @@ handle_count(Client &client, int argc, char *argv[])
{
ConstBuffer<const char *> args(argv + 1, argc - 1);
TagType group = TAG_NUM_OF_ITEM_TYPES;
if (args.size >= 2 && strcmp(args[args.size - 2], "group") == 0) {
const char *s = args[args.size - 1];
group = tag_name_parse_i(s);
if (group == TAG_NUM_OF_ITEM_TYPES) {
command_error(client, ACK_ERROR_ARG,
"Unknown tag type: %s", s);
return CommandResult::ERROR;
}
args.pop_back();
args.pop_back();
}
SongFilter filter;
if (!filter.Parse(args, false)) {
if (!args.IsEmpty() && !filter.Parse(args, false)) {
command_error(client, ACK_ERROR_ARG, "incorrect arguments");
return CommandResult::ERROR;
}
Error error;
return PrintSongCount(client, "", &filter, error)
return PrintSongCount(client, "", &filter, group, error)
? CommandResult::OK
: print_error(client, error);
}
......
......@@ -23,8 +23,10 @@
#include "Interface.hxx"
#include "client/Client.hxx"
#include "LightSong.hxx"
#include "tag/Set.hxx"
#include <functional>
#include <map>
struct SearchStats {
unsigned n_songs;
......@@ -34,6 +36,9 @@ struct SearchStats {
:n_songs(0), total_time_s(0) {}
};
class TagCountMap : public std::map<std::string, SearchStats> {
};
static void
PrintSearchStats(Client &client, const SearchStats &stats)
{
......@@ -43,6 +48,18 @@ PrintSearchStats(Client &client, const SearchStats &stats)
stats.n_songs, stats.total_time_s);
}
static void
Print(Client &client, TagType group, const TagCountMap &m)
{
assert(unsigned(group) < TAG_NUM_OF_ITEM_TYPES);
for (const auto &i : m) {
client_printf(client, "%s: %s\n",
tag_item_names[group], i.first.c_str());
PrintSearchStats(client, i.second);
}
}
static bool
stats_visitor_song(SearchStats &stats, const LightSong &song)
{
......@@ -52,9 +69,45 @@ stats_visitor_song(SearchStats &stats, const LightSong &song)
return true;
}
static bool
CollectGroupCounts(TagCountMap &map, TagType group, const Tag &tag)
{
bool found = false;
for (unsigned i = 0; i < tag.num_items; ++i) {
const TagItem &item = *tag.items[i];
if (item.type == group) {
auto r = map.insert(std::make_pair(item.value,
SearchStats()));
SearchStats &s = r.first->second;
++s.n_songs;
if (tag.time > 0)
s.total_time_s += tag.time;
found = true;
}
}
return found;
}
static bool
GroupCountVisitor(TagCountMap &map, TagType group, const LightSong &song)
{
assert(song.tag != nullptr);
const Tag &tag = *song.tag;
if (!CollectGroupCounts(map, group, tag) && group == TAG_ALBUM_ARTIST)
/* fall back to "Artist" if no "AlbumArtist" was found */
CollectGroupCounts(map, TAG_ARTIST, tag);
return true;
}
bool
PrintSongCount(Client &client, const char *name,
const SongFilter *filter,
TagType group,
Error &error)
{
const Database *db = client.GetDatabase(error);
......@@ -63,14 +116,32 @@ PrintSongCount(Client &client, const char *name,
const DatabaseSelection selection(name, true, filter);
SearchStats stats;
if (group == TAG_NUM_OF_ITEM_TYPES) {
/* no grouping */
using namespace std::placeholders;
const auto f = std::bind(stats_visitor_song, std::ref(stats),
_1);
if (!db->Visit(selection, f, error))
return false;
SearchStats stats;
using namespace std::placeholders;
const auto f = std::bind(stats_visitor_song, std::ref(stats),
_1);
if (!db->Visit(selection, f, error))
return false;
PrintSearchStats(client, stats);
} else {
/* group by the specified tag: store counts in a
std::map */
TagCountMap map;
using namespace std::placeholders;
const auto f = std::bind(GroupCountVisitor, std::ref(map),
group, _1);
if (!db->Visit(selection, f, error))
return false;
Print(client, group, map);
}
PrintSearchStats(client, stats);
return true;
}
......@@ -22,6 +22,9 @@
#include "Compiler.h"
#include <stdint.h>
enum TagType : uint8_t;
class Client;
class SongFilter;
class Error;
......@@ -30,6 +33,7 @@ gcc_nonnull(2)
bool
PrintSongCount(Client &client, const char *name,
const SongFilter *filter,
TagType group,
Error &error);
#endif
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