From 9dbcd6a5c8a9cb5c29867dd450b2af8934616f56 Mon Sep 17 00:00:00 2001
From: ailurux <ailuruxx@gmail.com>
Date: Thu, 30 May 2024 13:49:56 +1000
Subject: [PATCH] Fix prev/next behaviour on database iterator Fixes issue with
 apparent duplicated tracks in the infinite list

---
 src/tangara/database/database.cpp | 9 ++++++---
 src/tangara/lua/lua_database.cpp  | 4 ++--
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/tangara/database/database.cpp b/src/tangara/database/database.cpp
index 4064c3ed..f7cba610 100644
--- a/src/tangara/database/database.cpp
+++ b/src/tangara/database/database.cpp
@@ -704,9 +704,8 @@ Iterator::Iterator(std::shared_ptr<Database> db, const IndexKey::Header& header)
   key_ = {
       .prefix = {prefix.data(), prefix.size(), &memory::kSpiRamResource},
       .key = {},
-      .offset = 0,
+      .offset = -1,
   };
-  iterate(key_);
 }
 
 auto Iterator::value() const -> const std::optional<Record>& {
@@ -715,7 +714,11 @@ auto Iterator::value() const -> const std::optional<Record>& {
 
 auto Iterator::next() -> void {
   SearchKey new_key = key_;
-  new_key.offset = 1;
+  if (new_key.offset == -1) {
+    new_key.offset = 0;
+  } else {
+    new_key.offset = 1;
+  }
   iterate(new_key);
 }
 
diff --git a/src/tangara/lua/lua_database.cpp b/src/tangara/lua/lua_database.cpp
index 1afb01f0..bf84a399 100644
--- a/src/tangara/lua/lua_database.cpp
+++ b/src/tangara/lua/lua_database.cpp
@@ -162,7 +162,7 @@ static auto push_iterator(lua_State* state,
 
 static auto db_iterate_prev(lua_State* state) -> int {
   database::Iterator* it = db_check_iterator(state, 1);
-  std::optional<database::Record> res = (*it)--;
+  std::optional<database::Record> res = --(*it);
 
   if (res) {
     push_lua_record(state, *res);
@@ -175,7 +175,7 @@ static auto db_iterate_prev(lua_State* state) -> int {
 
 static auto db_iterate(lua_State* state) -> int {
   database::Iterator* it = db_check_iterator(state, 1);
-  std::optional<database::Record> res = (*it)++;
+  std::optional<database::Record> res = ++(*it);
 
   if (res) {
     push_lua_record(state, *res);