Basic playlists for upcoming

Beware under-testing and bugs. Just getting something barebones in so
that I can do rN+1 bringup

2 files changed, 15 insertions, 2 deletions

diff --git a/src/database/include/tag_parser.hpp b/src/database/include/tag_parser.hpp
index 4be5ad16..b0e9a151 100644
--- a/src/database/include/tag_parser.hpp
+++ b/src/database/include/tag_parser.hpp
@@ -8,6 +8,7 @@
 
 #include <string>
 
+#include "lru_cache.hpp"
 #include "track.hpp"
 
 namespace database {
@@ -21,8 +22,19 @@ class ITagParser {
 
 class TagParserImpl : public ITagParser {
  public:
-  virtual auto ReadAndParseTags(const std::string& path, TrackTags* out)
+  auto ReadAndParseTags(const std::string& path, TrackTags* out)
       -> bool override;
+
+ private:
+  /*
+   * Cache of tags that have already been extracted from files. Ideally this
+   * cache should be slightly larger than any page sizes in the UI.
+   */
+  util::LruCache<16, std::string, TrackTags> cache_;
+
+  // We could also consider keeping caches of artist name -> shared_string and
+  // similar. This hasn't been done yet, as this isn't a common workload in any
+  // of our UI.
 };
 
 }  // namespace database
diff --git a/src/database/include/track.hpp b/src/database/include/track.hpp
index 620fc59e..78f973ac 100644
--- a/src/database/include/track.hpp
+++ b/src/database/include/track.hpp
@@ -12,6 +12,7 @@
 #include <memory>
 #include <optional>
 #include <string>
+#include <unordered_map>
 #include <utility>
 
 #include "leveldb/db.h"
@@ -88,7 +89,7 @@ class TrackTags {
 
  private:
   Encoding encoding_;
-  std::map<Tag, shared_string> tags_;
+  std::unordered_map<Tag, shared_string> tags_;
 };
 
 /*