Merge pull request #1773 from ShaneMcGovernIE/codex/launcher-navigation-performance

perf(launcher): keep MODS and MOD INDEX navigation responsive

tests/engine/launcher_mod_downloads.lua

@@ -75,7 +75,8 @@ end
 do
   local ri = launcher()
   check(ri:_findStats(entry("nulled", nil, "someone/nulled")) == nil,
-        "a null count is not an answer; the repo is still consulted")
+        "a null count is not an answer")
+  ri:_requestFindStats(entry("nulled", nil, "someone/nulled"))
   eq(#fetched, 1, "which is the fetch the panel already made for dates")
 
   local bare = launcher()
@@ -83,7 +84,7 @@ do
   check(stats ~= nil and stats.total == nil,
         "a listing with neither counts nor a repo is resolved-but-unknown")
   check(stats.recent == nil, "and has nothing to trend on")
-  eq(#fetched, 1, "and queues nothing of its own")
+  eq(#fetched, 1, "and the explicit scheduler queues nothing without a repo")
 end
 
 -- A real zero is not unknown: the index has seen the releases and counted

tests/engine/launcher_navigation_perf.lua

@@ -0,0 +1,88 @@
+-- Launcher navigation performance seams.  MOD INDEX must not pay the full
+-- MODS validation pass, background index prefetch must not create a blocking
+-- overlay, and visible-row enrichment must be scheduled from update state
+-- rather than from immediate-mode draw calls.
+--   luajit tests/engine/launcher_navigation_perf.lua
+
+package.path = "./?.lua;./?/init.lua;" .. package.path
+if not _G.love then _G.love = require("tests.love_stub") end
+
+local T = require("tests.harness")
+local check, eq = T.check, T.eq
+local LauncherMods = require("src.mods.LauncherMods")
+local ModIndex = require("src.mods.ModIndex")
+local RomImporter = require("src.import.RomImporter")
+
+check(type(LauncherMods.installedVersions) == "function",
+  "LauncherMods exposes a lightweight installed-version scan")
+
+do
+  local old = LauncherMods.installedVersions
+  local called = 0
+  LauncherMods.installedVersions = function()
+    called = called + 1
+    return { alpha = "1.2.3" }
+  end
+  local imp = setmetatable({}, RomImporter)
+  local installed = imp:_findInstalledMap()
+  eq(called, 1, "MOD INDEX asks for the lightweight scan when MODS is cold")
+  eq(installed.alpha, "1.2.3",
+    "the lightweight scan supplies installed versions")
+  LauncherMods.installedVersions = old
+end
+
+do
+  local imp = setmetatable({ tab = "find", findLoaded = false }, RomImporter)
+  imp._refreshFindSources = function(self)
+    self.findSources = { { feed = "https://example.invalid/index.json" } }
+  end
+  local oldBegin = ModIndex.beginFetch
+  ModIndex.beginFetch = function() return { test = true } end
+  imp:_refreshFind(false)
+  check(imp._findFetch ~= nil, "background index refresh starts asynchronously")
+  eq(imp._busy, nil,
+    "background index refresh does not block navigation with a loader")
+  imp:_clearBusy()
+  imp._findFetch = nil
+  ModIndex.beginFetch = oldBegin
+end
+
+do
+  local requests = 0
+  local imp = setmetatable({ tab = "find", findLoaded = true,
+    _findVisibleEntries = {
+      { id = "one", thumbnail = "one.png", github = "a/one" },
+      { id = "two", thumbnail = "two.png", github = "a/two" },
+      { id = "three", thumbnail = "three.png", github = "a/three" },
+    } }, RomImporter)
+  imp._findThumb = function() return nil end
+  imp._findThumbPending = function() return false end
+  imp._findStatsCached = function() return nil end
+  imp._startFindThumb = function() requests = requests + 1 end
+  imp._requestFindStats = function() requests = requests + 1 end
+  imp:_queueFindEnrichment()
+  eq(requests, 4,
+    "update schedules a bounded thumbnail and stats batch for visible rows")
+end
+
+do
+  local requests = 0
+  local imp = setmetatable({}, RomImporter)
+  imp._findStatsCached = function() return nil end
+  imp._requestFindStats = function() requests = requests + 1 end
+  imp:_findStats({ id = "draw-only", github = "a/draw-only" })
+  eq(requests, 0, "reading row stats during draw never starts a request")
+end
+
+do
+  local f = assert(io.open("src/import/LauncherView.lua", "rb"))
+  local src = f:read("*a")
+  f:close()
+  local start = assert(src:find("local function buildFindPanel", 1, true))
+  local finish = assert(src:find("\nlocal function ", start + 1, true))
+  local panel = src:sub(start, finish - 1)
+  check(not panel:find("imp:_ensureMods()", 1, true),
+    "MOD INDEX panel does not force the full MODS list")
+end
+
+T.finish("launcher_navigation_perf")