idk man i wrote most of this in a fugue state whilst high on the couch with my catcustom
jacqueline
2 years ago
parent
aee0474191
commit
245d9ff4b9
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/*
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* Copyright 2023 jacqueline <me@jacqueline.id.au> |
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* |
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* SPDX-License-Identifier: GPL-3.0-only |
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*/ |
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#pragma once |
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#include <stdint.h> |
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#include <cstdint> |
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#include <string> |
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#include <variant> |
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#include <vector> |
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#include "leveldb/db.h" |
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#include "leveldb/slice.h" |
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#include "leveldb/write_batch.h" |
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#include "shared_string.h" |
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#include "track.hpp" |
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namespace database { |
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typedef uint8_t IndexId; |
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struct IndexInfo { |
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// Unique id for this index
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IndexId id; |
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// Localised, user-friendly description of this index. e.g. "Albums by Artist"
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// or "All Tracks".
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std::string name; |
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// Specifier for how this index breaks down the database.
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std::vector<Tag> components; |
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}; |
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struct IndexKey { |
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struct Header { |
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// The index that this key was created for.
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IndexId id; |
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// The number of components of IndexInfo that have already been filtered.
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// For example, if an index consists of { kGenre, kArtist }, and this key
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// represents an artist, then depth = 1.
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std::uint8_t depth; |
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// The cumulative hash of all filtered components, in order. For example, if
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// an index consists of { kArtist, kAlbum, kTitle }, and we are at depth = 2
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// then this may contain hash(hash("Jacqueline"), "My Cool Album").
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std::uint64_t components_hash; |
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}; |
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Header header; |
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// The filterable / selectable item that this key represents. "Jacqueline" for
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// kArtist, "My Cool Album" for kAlbum, etc.
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std::optional<std::string> item; |
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// If this is a leaf component, the track id for this record.
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// This could reasonably be the value for a record, but we keep it as a part
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// of the key to help with disambiguation.
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std::optional<TrackId> track; |
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}; |
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auto Index(const IndexInfo&, const Track&, leveldb::WriteBatch*) -> bool; |
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auto ExpandHeader(const IndexKey::Header&, const std::optional<std::string>&) |
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-> IndexKey::Header; |
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// Predefined indexes
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// TODO(jacqueline): Make these defined at runtime! :)
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extern const IndexInfo kAlbumsByArtist; |
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extern const IndexInfo kTracksByGenre; |
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extern const IndexInfo kAllTracks; |
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} // namespace database
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@ -0,0 +1,88 @@ |
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/*
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* Copyright 2023 jacqueline <me@jacqueline.id.au> |
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* |
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* SPDX-License-Identifier: GPL-3.0-only |
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*/ |
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#include "index.hpp" |
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#include <stdint.h> |
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#include <variant> |
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#include "komihash.h" |
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#include "leveldb/write_batch.h" |
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#include "records.hpp" |
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namespace database { |
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const IndexInfo kAlbumsByArtist{ |
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.id = 1, |
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.name = "Albums by Artist", |
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.components = {Tag::kArtist, Tag::kAlbum, Tag::kAlbumTrack}, |
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}; |
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const IndexInfo kTracksByGenre{ |
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.id = 2, |
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.name = "Tracks by Genre", |
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.components = {Tag::kGenre, Tag::kTitle}, |
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}; |
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const IndexInfo kAllTracks{ |
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.id = 3, |
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.name = "All Tracks", |
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.components = {Tag::kTitle}, |
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}; |
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auto Index(const IndexInfo& info, const Track& t, leveldb::WriteBatch* batch) |
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-> bool { |
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IndexKey key{ |
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.header{ |
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.id = info.id, |
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.depth = 0, |
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.components_hash = 0, |
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}, |
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.item = {}, |
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.track = {}, |
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}; |
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for (std::uint8_t i = 0; i < info.components.size(); i++) { |
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// Fill in the text for this depth.
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auto text = t.tags().at(info.components.at(i)); |
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if (text) { |
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key.item = *text; |
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} else { |
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key.item = {}; |
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} |
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// If this is the last component, then we should also fill in the track id.
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if (i == info.components.size() - 1) { |
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key.track = t.data().id(); |
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} else { |
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key.track = {}; |
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} |
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auto encoded = EncodeIndexKey(key); |
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batch->Put(encoded.slice, leveldb::Slice{}); |
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// If there are more components after this, then we need to finish by
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// narrowing the header with the current title.
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if (i < info.components.size() - 1) { |
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key.header = ExpandHeader(key.header, key.item); |
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} |
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} |
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return true; |
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} |
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auto ExpandHeader(const IndexKey::Header& header, |
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const std::optional<std::string>& component) |
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-> IndexKey::Header { |
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IndexKey::Header ret{header}; |
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ret.depth++; |
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if (component) { |
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ret.components_hash = |
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komihash(component->data(), component->size(), ret.components_hash); |
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} else { |
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ret.components_hash = komihash(NULL, 0, ret.components_hash); |
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} |
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return ret; |
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} |
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} // namespace database
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