Remove templating of Continuation

src/app_console/app_console.cpp

@@ -194,7 +194,7 @@ int CmdDbTracks(int argc, char** argv) {
     }
     if (res->next_page()) {
       auto continuation = res->next_page().value();
-      res.reset(db->GetPage(&continuation).get());
+      res.reset(db->GetPage<database::Track>(&continuation).get());
     } else {
       break;
     }

src/database/database.cpp

@@ -355,23 +355,23 @@ auto Database::GetTracksByIndex(const IndexInfo& index, std::size_t page_size)
             .components_hash = 0,
         };
         OwningSlice prefix = EncodeIndexPrefix(header);
-        Continuation<IndexRecord> c{.prefix = prefix.data,
-                                    .start_key = prefix.data,
-                                    .forward = true,
-                                    .was_prev_forward = true,
-                                    .page_size = page_size};
-        return dbGetPage(c);
+        Continuation c{.prefix = prefix.data,
+                       .start_key = prefix.data,
+                       .forward = true,
+                       .was_prev_forward = true,
+                       .page_size = page_size};
+        return dbGetPage<IndexRecord>(c);
       });
 }
 
 auto Database::GetTracks(std::size_t page_size) -> std::future<Result<Track>*> {
   return worker_task_->Dispatch<Result<Track>*>([=, this]() -> Result<Track>* {
-    Continuation<Track> c{.prefix = EncodeDataPrefix().data,
-                          .start_key = EncodeDataPrefix().data,
-                          .forward = true,
-                          .was_prev_forward = true,
-                          .page_size = page_size};
-    return dbGetPage(c);
+    Continuation c{.prefix = EncodeDataPrefix().data,
+                   .start_key = EncodeDataPrefix().data,
+                   .forward = true,
+                   .was_prev_forward = true,
+                   .page_size = page_size};
+    return dbGetPage<Track>(c);
   });
 }
 
@@ -379,28 +379,27 @@ auto Database::GetDump(std::size_t page_size)
     -> std::future<Result<std::pmr::string>*> {
   return worker_task_->Dispatch<Result<std::pmr::string>*>(
       [=, this]() -> Result<std::pmr::string>* {
-        Continuation<std::pmr::string> c{.prefix = "",
-                                         .start_key = "",
-                                         .forward = true,
-                                         .was_prev_forward = true,
-                                         .page_size = page_size};
-        return dbGetPage(c);
+        Continuation c{.prefix = "",
+                       .start_key = "",
+                       .forward = true,
+                       .was_prev_forward = true,
+                       .page_size = page_size};
+        return dbGetPage<std::pmr::string>(c);
       });
 }
 
 template <typename T>
-auto Database::GetPage(Continuation<T>* c) -> std::future<Result<T>*> {
-  Continuation<T> copy = *c;
+auto Database::GetPage(Continuation* c) -> std::future<Result<T>*> {
+  Continuation copy = *c;
   return worker_task_->Dispatch<Result<T>*>(
-      [=, this]() -> Result<T>* { return dbGetPage(copy); });
+      [=, this]() -> Result<T>* { return dbGetPage<T>(copy); });
 }
 
-template auto Database::GetPage<Track>(Continuation<Track>* c)
+template auto Database::GetPage<Track>(Continuation* c)
     -> std::future<Result<Track>*>;
-template auto Database::GetPage<IndexRecord>(Continuation<IndexRecord>* c)
+template auto Database::GetPage<IndexRecord>(Continuation* c)
     -> std::future<Result<IndexRecord>*>;
-template auto Database::GetPage<std::pmr::string>(
-    Continuation<std::pmr::string>* c)
+template auto Database::GetPage<std::pmr::string>(Continuation* c)
     -> std::future<Result<std::pmr::string>*>;
 
 auto Database::dbMintNewTrackId() -> TrackId {
@@ -477,7 +476,7 @@ auto Database::dbCreateIndexesForTrack(const Track& track) -> void {
 }
 
 template <typename T>
-auto Database::dbGetPage(const Continuation<T>& c) -> Result<T>* {
+auto Database::dbGetPage(const Continuation& c) -> Result<T>* {
   // Work out our starting point. Sometimes this will already done.
   std::unique_ptr<leveldb::Iterator> it{
       db_->NewIterator(leveldb::ReadOptions{})};
@@ -524,13 +523,13 @@ auto Database::dbGetPage(const Continuation<T>& c) -> Result<T>* {
   }
 
   // Work out the new continuations.
-  std::optional<Continuation<T>> next_page;
+  std::optional<Continuation> next_page;
   if (c.forward) {
     if (it != nullptr) {
       // We were going forward, and now we want the next page.
       std::pmr::string key{it->key().data(), it->key().size(),
                            &memory::kSpiRamResource};
-      next_page = Continuation<T>{
+      next_page = Continuation{
           .prefix = c.prefix,
           .start_key = key,
           .forward = true,
@@ -543,7 +542,7 @@ auto Database::dbGetPage(const Continuation<T>& c) -> Result<T>* {
     // We were going backwards, and now we want the next page. This is a
     // reversal, to set the start key to the first record we saw and mark that
     // it's off by one.
-    next_page = Continuation<T>{
+    next_page = Continuation{
         .prefix = c.prefix,
         .start_key = *first_key,
         .forward = true,
@@ -552,11 +551,11 @@ auto Database::dbGetPage(const Continuation<T>& c) -> Result<T>* {
     };
   }
 
-  std::optional<Continuation<T>> prev_page;
+  std::optional<Continuation> prev_page;
   if (c.forward) {
     // We were going forwards, and now we want the previous page. Set the search
     // key to the first result we saw, and mark that it's off by one.
-    prev_page = Continuation<T>{
+    prev_page = Continuation{
         .prefix = c.prefix,
         .start_key = *first_key,
         .forward = false,
@@ -568,7 +567,7 @@ auto Database::dbGetPage(const Continuation<T>& c) -> Result<T>* {
       // We were going backwards, and we still want to go backwards.
       std::pmr::string key{it->key().data(), it->key().size(),
                            &memory::kSpiRamResource};
-      prev_page = Continuation<T>{
+      prev_page = Continuation{
           .prefix = c.prefix,
           .start_key = key,
           .forward = false,
@@ -582,10 +581,10 @@ auto Database::dbGetPage(const Continuation<T>& c) -> Result<T>* {
   return new Result<T>(std::move(records), next_page, prev_page);
 }
 
-template auto Database::dbGetPage<Track>(const Continuation<Track>& c)
+template auto Database::dbGetPage<Track>(const Continuation& c)
     -> Result<Track>*;
-template auto Database::dbGetPage<std::pmr::string>(
-    const Continuation<std::pmr::string>& c) -> Result<std::pmr::string>*;
+template auto Database::dbGetPage<std::pmr::string>(const Continuation& c)
+    -> Result<std::pmr::string>*;
 
 template <>
 auto Database::ParseRecord<IndexRecord>(const leveldb::Slice& key,
@@ -668,13 +667,13 @@ auto IndexRecord::track() const -> std::optional<TrackId> {
 }
 
 auto IndexRecord::Expand(std::size_t page_size) const
-    -> std::optional<Continuation<IndexRecord>> {
+    -> std::optional<Continuation> {
   if (track_) {
     return {};
   }
   IndexKey::Header new_header = ExpandHeader(key_.header, key_.item);
   OwningSlice new_prefix = EncodeIndexPrefix(new_header);
-  return Continuation<IndexRecord>{
+  return Continuation{
       .prefix = new_prefix.data,
       .start_key = new_prefix.data,
       .forward = true,

src/database/include/database.hpp

@@ -31,7 +31,6 @@
 
 namespace database {
 
-template <typename T>
 struct Continuation {
   std::pmr::string prefix;
   std::pmr::string start_key;
@@ -52,12 +51,12 @@ class Result {
     return values_;
   }
 
-  auto next_page() -> std::optional<Continuation<T>>& { return next_page_; }
-  auto prev_page() -> std::optional<Continuation<T>>& { return prev_page_; }
+  auto next_page() -> std::optional<Continuation>& { return next_page_; }
+  auto prev_page() -> std::optional<Continuation>& { return prev_page_; }
 
   Result(const std::vector<std::shared_ptr<T>>&& values,
-         std::optional<Continuation<T>> next,
-         std::optional<Continuation<T>> prev)
+         std::optional<Continuation> next,
+         std::optional<Continuation> prev)
       : values_(values), next_page_(next), prev_page_(prev) {}
 
   Result(const Result&) = delete;
@@ -65,8 +64,8 @@ class Result {
 
  private:
   std::vector<std::shared_ptr<T>> values_;
-  std::optional<Continuation<T>> next_page_;
-  std::optional<Continuation<T>> prev_page_;
+  std::optional<Continuation> next_page_;
+  std::optional<Continuation> prev_page_;
 };
 
 class IndexRecord {
@@ -78,7 +77,7 @@ class IndexRecord {
   auto text() const -> std::optional<std::pmr::string>;
   auto track() const -> std::optional<TrackId>;
 
-  auto Expand(std::size_t) const -> std::optional<Continuation<IndexRecord>>;
+  auto Expand(std::size_t) const -> std::optional<Continuation>;
 
  private:
   IndexKey key_;
@@ -120,7 +119,7 @@ class Database {
   auto GetDump(std::size_t page_size) -> std::future<Result<std::pmr::string>*>;
 
   template <typename T>
-  auto GetPage(Continuation<T>* c) -> std::future<Result<T>*>;
+  auto GetPage(Continuation* c) -> std::future<Result<T>*>;
 
   Database(const Database&) = delete;
   Database& operator=(const Database&) = delete;
@@ -153,7 +152,7 @@ class Database {
   auto dbCreateIndexesForTrack(const Track& track) -> void;
 
   template <typename T>
-  auto dbGetPage(const Continuation<T>& c) -> Result<T>*;
+  auto dbGetPage(const Continuation& c) -> Result<T>*;
 
   template <typename T>
   auto ParseRecord(const leveldb::Slice& key, const leveldb::Slice& val)

src/playlist/source.cpp

@@ -68,7 +68,7 @@ auto IndexRecordSource::Advance() -> std::optional<database::TrackId> {
       return {};
     }
 
-    current_page_.reset(db->GetPage(&*next_page).get());
+    current_page_.reset(db->GetPage<database::IndexRecord>(&*next_page).get());
     current_item_ = 0;
   }
 
@@ -92,7 +92,7 @@ auto IndexRecordSource::Previous() -> std::optional<database::TrackId> {
       return {};
     }
 
-    current_page_.reset(db->GetPage(&*prev_page).get());
+    current_page_.reset(db->GetPage<database::IndexRecord>(&*prev_page).get());
     current_item_ = current_page_->values().size() - 1;
   }
 
@@ -124,7 +124,7 @@ auto IndexRecordSource::Peek(std::size_t n, std::vector<database::TrackId>* out)
       }
       // TODO(jacqueline): It would probably be a good idea to hold onto these
       // peeked pages, to avoid needing to look them up again later.
-      working_page.reset(db->GetPage(&*next_page).get());
+      working_page.reset(db->GetPage<database::IndexRecord>(&*next_page).get());
       working_item = 0;
     }
 

src/ui/screen_track_browser.cpp

@@ -262,7 +262,7 @@ auto TrackBrowser::FetchNewPage(Position pos) -> void {
     return;
   }
 
-  std::optional<database::Continuation<database::IndexRecord>> cont;
+  std::optional<database::Continuation> cont;
   switch (pos) {
     case START:
       cont = current_pages_.front()->prev_page();
@@ -294,7 +294,7 @@ auto TrackBrowser::FetchNewPage(Position pos) -> void {
   }
 
   loading_pos_ = pos;
-  loading_page_ = db->GetPage(&cont.value());
+  loading_page_ = db->GetPage<database::IndexRecord>(&cont.value());
 }
 
 auto TrackBrowser::GetNumRecords() -> std::size_t {

src/ui/ui_fsm.cpp

@@ -299,7 +299,7 @@ void Browse::react(const internal::RecordSelected& ev) {
     if (!cont) {
       return;
     }
-    auto query = db->GetPage(&cont.value());
+    auto query = db->GetPage<database::IndexRecord>(&cont.value());
     std::pmr::string title = record->text().value_or("TODO");
     PushScreen(std::make_shared<screens::TrackBrowser>(
         sTopBarModel, sServices->database(), title, std::move(query)));