Add basic lua browser screen

lib/lvgl/src/extra/widgets/list/lv_list.c

@@ -91,7 +91,7 @@ lv_obj_t * lv_list_add_btn(lv_obj_t * list, const void * icon, const char * txt)
     if(txt) {
         lv_obj_t * label = lv_label_create(obj);
         lv_label_set_text(label, txt);
-        lv_label_set_long_mode(label, LV_LABEL_LONG_SCROLL_CIRCULAR);
+        lv_label_set_long_mode(label, LV_LABEL_LONG_DOT);
         lv_obj_set_flex_grow(label, 1);
     }
 

lua/browser.lua

@@ -0,0 +1,113 @@
+local lvgl = require("lvgl")
+local widgets = require("widgets")
+local legacy_ui = require("legacy_ui")
+local database = require("database")
+local backstack = require("backstack")
+
+local browser = {}
+
+function browser.create(opts)
+  local screen = {}
+  screen.root = lvgl.Object(nil, {
+    flex = {
+      flex_direction = "column",
+      flex_wrap = "wrap",
+      justify_content = "flex-start",
+      align_items = "flex-start",
+      align_content = "flex-start",
+    },
+    w = lvgl.HOR_RES(),
+    h = lvgl.VER_RES(),
+  })
+  screen.root:center()
+
+  screen.status_bar = widgets.StatusBar(screen.root, {
+    back_cb = backstack.pop,
+    title = opts.title,
+  })
+
+  if opts.breadcrumb then
+    local header = screen.root:Object {
+      flex = {
+        flex_direction = "column",
+        flex_wrap = "wrap",
+        justify_content = "flex-start",
+        align_items = "flex-start",
+        align_content = "flex-start",
+      },
+      w = lvgl.HOR_RES(),
+      h = lvgl.SIZE_CONTENT,
+      pad_left = 4,
+      pad_right = 4,
+      pad_top = 2,
+      pad_bottom = 2,
+      bg_opa = lvgl.OPA(100),
+      bg_color = "#f3e5f5",
+      scrollbar_mode = lvgl.SCROLLBAR_MODE.OFF,
+    }
+
+    header:Label { text = opts.breadcrumb }
+
+    local buttons = header:Object({
+      flex = {
+        flex_direction = "row",
+        flex_wrap = "wrap",
+        justify_content = "flex-end",
+        align_items = "center",
+        align_content = "center",
+      },
+      w = lvgl.PCT(100),
+      h = lvgl.SIZE_CONTENT,
+      pad_column = 4,
+    })
+    local enqueue = buttons:Button {}
+    enqueue:Label { text = "Enqueue" }
+    enqueue:add_flag(lvgl.FLAG.HIDDEN)
+    local play = buttons:Button {}
+    play:Label { text = "Play all" }
+  end
+
+  screen.list = lvgl.List(screen.root, {
+    w = lvgl.PCT(100),
+    h = lvgl.PCT(100),
+    flex_grow = 1,
+    scrollbar_mode = lvgl.SCROLLBAR_MODE.OFF,
+  })
+
+  screen.focused_item = 0
+  screen.last_item = 0
+  screen.add_item = function(item)
+    if not item then return end
+    screen.last_item = screen.last_item + 1
+    local this_item = screen.last_item
+    local btn = screen.list:add_btn(nil, tostring(item))
+    btn:onClicked(function()
+      local contents = item:contents()
+      if type(contents) == "function" then
+        backstack.push(function()
+          return browser.create({
+            title = opts.title,
+            iterator = contents,
+            breadcrumb = tostring(item),
+          })
+        end)
+      else
+        print("selected track", contents)
+      end
+    end)
+    btn:onevent(lvgl.EVENT.FOCUSED, function()
+      screen.focused_item = this_item
+      if screen.last_item - 5 < this_item then
+        opts.iterator(screen.add_item)
+      end
+    end)
+  end
+
+  for _ = 1, 8 do
+    opts.iterator(screen.add_item)
+  end
+
+  return screen
+end
+
+return browser.create

lua/main_menu.lua

@@ -2,6 +2,8 @@ local lvgl = require("lvgl")
 local widgets = require("widgets")
 local legacy_ui = require("legacy_ui")
 local database = require("database")
+local backstack = require("backstack")
+local browser = require("browser")
 
 return function()
   local menu = {}
@@ -35,6 +37,12 @@ return function()
     local btn = menu.list:add_btn(nil, tostring(idx))
     btn:onClicked(function()
       legacy_ui.open_browse(id);
+      -- backstack.push(function()
+      --   return browser {
+      --     title = tostring(idx),
+      --     iterator = idx:iter()
+      --   }
+      -- end)
     end)
   end
 

lua/widgets.lua

@@ -17,23 +17,20 @@ function widgets.StatusBar(parent, opts)
     },
     w = lvgl.HOR_RES(),
     h = lvgl.SIZE_CONTENT,
-    bg_opa = lvgl.OPA(100),
-    bg_color = "#fff",
     pad_top = 1,
     pad_bottom = 1,
     pad_column = 1,
-    shadow_width = 6,
-    shadow_opa = lvgl.OPA(50),
-    shaddow_ofs_x = 0,
+    bg_opa = lvgl.OPA(100),
+    bg_color = "#e1bee7",
     scrollbar_mode = lvgl.SCROLLBAR_MODE.OFF,
   }
 
   if opts.back_cb then
-    status_bar.back = status_bar.root:Label {
+    status_bar.back = status_bar.root:Button {
       w = lvgl.SIZE_CONTENT,
       h = 12,
-      text = "<",
     }
+    status_bar.back:Label({ text = "<", align = lvgl.ALIGN.CENTER })
     status_bar.back:onClicked(opts.back_cb)
   end
 
@@ -44,7 +41,7 @@ function widgets.StatusBar(parent, opts)
     flex_grow = 1,
   }
   if opts.title then
-    status_bar.title.set { text = opts.title }
+    status_bar.title:set { text = opts.title }
   end
 
   status_bar.playing = status_bar.root:Image {}

src/database/database.cpp

@@ -846,8 +846,7 @@ auto IndexRecord::Expand(std::size_t page_size) const
   if (track_) {
     return {};
   }
-  IndexKey::Header new_header = ExpandHeader(key_.header, key_.item);
-  std::string new_prefix = EncodeIndexPrefix(new_header);
+  std::string new_prefix = EncodeIndexPrefix(ExpandHeader());
   return Continuation{
       .prefix = {new_prefix.data(), new_prefix.size()},
       .start_key = {new_prefix.data(), new_prefix.size()},
@@ -857,6 +856,10 @@ auto IndexRecord::Expand(std::size_t page_size) const
   };
 }
 
+auto IndexRecord::ExpandHeader() const -> IndexKey::Header {
+  return ::database::ExpandHeader(key_.header, key_.item);
+}
+
 Iterator::Iterator(std::weak_ptr<Database> db, const IndexInfo& idx)
     : db_(db), pos_mutex_(), current_pos_(), prev_pos_() {
   std::string prefix = EncodeIndexPrefix(
@@ -887,6 +890,11 @@ auto Iterator::Next(Callback cb) -> void {
         db->dbGetPage<IndexRecord>(*current_pos_)};
     prev_pos_ = current_pos_;
     current_pos_ = res->next_page();
+    if (!res || res->values().empty() || !res->values()[0]) {
+      ESP_LOGI(kTag, "dropping empty result");
+      InvokeNull(cb);
+      return;
+    }
     std::invoke(cb, *res->values()[0]);
   });
 }

src/database/include/database.hpp

@@ -80,6 +80,7 @@ class IndexRecord {
   auto track() const -> std::optional<TrackId>;
 
   auto Expand(std::size_t) const -> std::optional<Continuation>;
+  auto ExpandHeader() const -> IndexKey::Header;
 
  private:
   IndexKey key_;

src/lua/lua_database.cpp

@@ -20,7 +20,9 @@
 #include "event_queue.hpp"
 #include "index.hpp"
 #include "property.hpp"
+#include "records.hpp"
 #include "service_locator.hpp"
+#include "track.hpp"
 #include "ui_events.hpp"
 
 namespace lua {
@@ -55,6 +57,42 @@ static auto indexes(lua_State* state) -> int {
 static const struct luaL_Reg kDatabaseFuncs[] = {{"indexes", indexes},
                                                  {NULL, NULL}};
 
+/*
+ * Struct to be used as userdata for the Lua representation of database records.
+ * In order to push these large values into PSRAM as much as possible, memory
+ * for these is allocated and managed by Lua. This struct must therefore be
+ * trivially copyable.
+ */
+struct LuaRecord {
+  database::TrackId id_or_zero;
+  database::IndexKey::Header header_at_next_depth;
+  size_t text_size;
+  char text[];
+};
+
+static_assert(std::is_trivially_copyable_v<LuaRecord> == true);
+
+static auto push_lua_record(lua_State* L, const database::IndexRecord& r)
+    -> void {
+  // Bake out the text into something concrete.
+  auto text = r.text().value_or("");
+
+  // Create and init the userdata.
+  LuaRecord* record = reinterpret_cast<LuaRecord*>(
+      lua_newuserdata(L, sizeof(LuaRecord) + text.size()));
+  luaL_setmetatable(L, kDbRecordMetatable);
+
+  // Init all the fields
+  *record = {
+      .id_or_zero = r.track().value_or(0),
+      .header_at_next_depth = r.ExpandHeader(),
+      .text_size = text.size(),
+  };
+
+  // Copy the string data across.
+  std::memcpy(record->text, text.data(), text.size());
+}
+
 static auto db_iterate(lua_State* state) -> int {
   luaL_checktype(state, 1, LUA_TFUNCTION);
   int callback_ref = luaL_ref(state, LUA_REGISTRYINDEX);
@@ -66,11 +104,7 @@ static auto db_iterate(lua_State* state) -> int {
     events::Ui().RunOnTask([=]() {
       lua_rawgeti(state, LUA_REGISTRYINDEX, callback_ref);
       if (res) {
-        database::IndexRecord** record =
-            reinterpret_cast<database::IndexRecord**>(
-                lua_newuserdata(state, sizeof(uintptr_t)));
-        *record = new database::IndexRecord(*res);
-        luaL_setmetatable(state, kDbRecordMetatable);
+        push_lua_record(state, *res);
       } else {
         lua_pushnil(state);
       }
@@ -105,40 +139,37 @@ static auto push_iterator(
   lua_pushcclosure(state, db_iterate, 1);
 }
 
+
 static auto record_text(lua_State* state) -> int {
-  database::IndexRecord* data = *reinterpret_cast<database::IndexRecord**>(
+  LuaRecord* data = reinterpret_cast<LuaRecord*>(
       luaL_checkudata(state, 1, kDbRecordMetatable));
-  lua_pushstring(state,
-                 data->text().value_or("[tell jacqueline u saw this]").c_str());
+  lua_pushlstring(state, data->text, data->text_size);
   return 1;
 }
 
 static auto record_contents(lua_State* state) -> int {
-  database::IndexRecord* data = *reinterpret_cast<database::IndexRecord**>(
+  LuaRecord* data = reinterpret_cast<LuaRecord*>(
       luaL_checkudata(state, 1, kDbRecordMetatable));
 
-  if (data->track()) {
-    lua_pushinteger(state, *data->track());
+  if (data->id_or_zero) {
+    lua_pushinteger(state, data->id_or_zero);
   } else {
-    push_iterator(state, data->Expand(1).value());
+    std::string p = database::EncodeIndexPrefix(data->header_at_next_depth);
+    push_iterator(state, database::Continuation{
+                             .prefix = {p.data(), p.size()},
+                             .start_key = {p.data(), p.size()},
+                             .forward = true,
+                             .was_prev_forward = true,
+                             .page_size = 1,
+                         });
   }
 
   return 1;
 }
 
-static auto record_gc(lua_State* state) -> int {
-  database::IndexRecord** data = reinterpret_cast<database::IndexRecord**>(
-      luaL_checkudata(state, 1, kDbRecordMetatable));
-  if (data != NULL) {
-    delete *data;
-  }
-  return 0;
-}
-
 static const struct luaL_Reg kDbRecordFuncs[] = {{"title", record_text},
                                                  {"contents", record_contents},
                                                  {"__tostring", record_text},
-                                                 {"__gc", record_gc},
                                                  {NULL, NULL}};
 
 static auto index_name(lua_State* state) -> int {

src/ui/ui_fsm.cpp

@@ -219,6 +219,7 @@ void Lua::entry() {
             {"pop", [&](lua_State* s) { return PopLuaScreen(s); }},
         });
 
+    sCurrentScreen.reset();
     sLua->RunScript("/lua/main.lua");
   }
 }
@@ -243,12 +244,6 @@ auto Lua::PushLuaScreen(lua_State* s) -> int {
   // Store the reference for the table the constructor returned.
   new_screen->SetObjRef(s);
 
-  // Ensure that we don't pollute the new screen's group. We leave the luavgl
-  // root alone.
-  // FIXME: maybe we should set the luavgl root to some catch-all that throws
-  // when anything is added to it? this may help catch bugs!
-  lv_group_set_default(NULL);
-
   // Finally, push the now-initialised screen as if it were a regular C++
   // screen.
   PushScreen(new_screen);
@@ -256,12 +251,16 @@ auto Lua::PushLuaScreen(lua_State* s) -> int {
   return 0;
 }
 
-auto Lua::PopLuaScreen(lua_State*) -> int {
+auto Lua::PopLuaScreen(lua_State* s) -> int {
   PopScreen();
+  luavgl_set_root(s, sCurrentScreen->root());
+  lv_group_set_default(sCurrentScreen->group());
   return 0;
 }
 
-void Lua::exit() {}
+void Lua::exit() {
+  lv_group_set_default(NULL);
+}
 
 void Lua::react(const internal::IndexSelected& ev) {
   auto db = sServices->database().lock();