Move DB interactions to a background thread

1 files changed, 60 insertions, 17 deletions

diff --git a/src/database/include/database.hpp b/src/database/include/database.hpp
index cb1437df..bc102ca8 100644
--- a/src/database/include/database.hpp
+++ b/src/database/include/database.hpp
@@ -1,29 +1,85 @@
 #pragma once
 
-#include <string>
+#include <cstdint>
+#include <future>
 #include <memory>
 #include <optional>
+#include <string>
+#include <utility>
+#include <vector>
 
 #include "leveldb/cache.h"
 #include "leveldb/db.h"
 #include "leveldb/iterator.h"
+#include "leveldb/slice.h"
 #include "result.hpp"
 
 namespace database {
 
-class Iterator;
+struct Artist {
+  std::string name;
+};
+
+struct Album {
+  std::string name;
+};
+
+typedef uint64_t SongId_t;
+
+struct Song {
+  std::string title;
+  uint64_t id;
+};
+
+struct SongMetadata {};
+
+template <typename T>
+class DbResult {
+ public:
+  DbResult(const std::vector<T>& values, std::unique_ptr<leveldb::Iterator> it)
+      : values_(values), it_(std::move(it)) {}
+  auto values() -> std::vector<T> { return values_; }
+  auto it() -> leveldb::Iterator* { return it_.release(); };
+
+ private:
+  std::vector<T> values_;
+  std::unique_ptr<leveldb::Iterator> it_;
+};
 
 class Database {
  public:
   enum DatabaseError {
+    ALREADY_OPEN,
     FAILED_TO_OPEN,
   };
   static auto Open() -> cpp::result<Database*, DatabaseError>;
 
   ~Database();
 
-  auto Initialise() -> void;
-  auto ByTitle() -> Iterator;
+  auto Populate() -> std::future<void>;
+
+  auto GetArtists(std::size_t page_size) -> std::future<DbResult<Artist>>;
+  auto GetMoreArtists(std::size_t page_size, DbResult<Artist> continuation)
+      -> std::future<DbResult<Artist>>;
+
+  auto GetAlbums(std::size_t page_size, std::optional<Artist> artist)
+      -> std::future<DbResult<Album>>;
+  auto GetMoreAlbums(std::size_t page_size, DbResult<Album> continuation)
+      -> std::future<DbResult<Album>>;
+
+  auto GetSongs(std::size_t page_size) -> std::future<DbResult<Song>>;
+  auto GetSongs(std::size_t page_size, std::optional<Artist> artist)
+      -> std::future<DbResult<Song>>;
+  auto GetSongs(std::size_t page_size,
+                std::optional<Artist> artist,
+                std::optional<Album> album) -> std::future<DbResult<Song>>;
+  auto GetMoreSongs(std::size_t page_size, DbResult<Song> continuation)
+      -> std::future<DbResult<Song>>;
+
+  auto GetSongIds(std::optional<Artist> artist, std::optional<Album> album)
+      -> std::future<std::vector<SongId_t>>;
+  auto GetSongFilePath(SongId_t id) -> std::future<std::optional<std::string>>;
+  auto GetSongMetadata(SongId_t id) -> std::future<std::optional<SongMetadata>>;
 
   Database(const Database&) = delete;
   Database& operator=(const Database&) = delete;
@@ -35,17 +91,4 @@ class Database {
   Database(leveldb::DB* db, leveldb::Cache* cache);
 };
 
-class Iterator {
-  public:
-    explicit Iterator(leveldb::Iterator *it) : it_(it) {}
-
-    auto Next() -> std::optional<std::string>;
-
-    Iterator(const Iterator&) = delete;
-    Iterator& operator=(const Iterator&) = delete;
-
-  private:
-    std::unique_ptr<leveldb::Iterator> it_;
-};
-
 }  // namespace database