1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
/*
* Copyright 2023 jacqueline <me@jacqueline.id.au>
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#pragma once
#include <stdint.h>
#include <cstdint>
#include <string>
#include <variant>
#include <vector>
#include "collation.hpp"
#include "leveldb/db.h"
#include "leveldb/slice.h"
#include "leveldb/write_batch.h"
#include "memory_resource.hpp"
#include "track.hpp"
namespace database {
typedef uint8_t IndexId;
struct IndexInfo {
// Unique id for this index
IndexId id;
// Localised, user-friendly description of this index. e.g. "Albums by Artist"
// or "All Tracks".
std::pmr::string name;
// Specifier for how this index breaks down the database.
std::vector<Tag> components;
};
struct IndexKey {
struct Header {
// The index that this key was created for.
IndexId id;
// The number of components of IndexInfo that have already been filtered.
// For example, if an index consists of { kGenre, kArtist }, and this key
// represents an artist, then depth = 1.
std::uint8_t depth;
// The cumulative hash of all filtered components, in order. For example, if
// an index consists of { kArtist, kAlbum, kTitle }, and we are at depth = 2
// then this may contain hash(hash("Jacqueline"), "My Cool Album").
std::uint64_t components_hash;
bool operator==(const Header&) const = default;
};
Header header;
// The filterable / selectable item that this key represents. "Jacqueline" for
// kArtist, "My Cool Album" for kAlbum, etc.
std::optional<std::pmr::string> item;
// If this is a leaf component, the track id for this record.
// This could reasonably be the value for a record, but we keep it as a part
// of the key to help with disambiguation.
std::optional<TrackId> track;
};
auto Index(locale::ICollator&, const IndexInfo&, const Track&)
-> std::vector<std::pair<IndexKey, std::string>>;
auto ExpandHeader(const IndexKey::Header&,
const std::optional<std::pmr::string>&) -> IndexKey::Header;
// Predefined indexes
// TODO(jacqueline): Make these defined at runtime! :)
extern const IndexInfo kAlbumsByArtist;
extern const IndexInfo kTracksByGenre;
extern const IndexInfo kAllTracks;
extern const IndexInfo kAllAlbums;
} // namespace database
|
