app.lua

   1 -- love.run: main entrypoint function for LÖVE
   2 --
   3 -- Most apps can just use the default shown in https://love2d.org/wiki/love.run,
   4 -- but we need to override it to:
   5 --   * recover from errors (by switching to the source editor)
   6 --   * run all tests (functions starting with 'test_') on startup, and
   7 --   * save some state that makes it possible to switch between the main app
   8 --     and a source editor, while giving each the illusion of complete
   9 --     control.
  10 function love.run()
  11   Version, Major_version = App.love_version()
  12   App.snapshot_love()
  13   -- Tests always run at the start.
  14   App.run_tests_and_initialize()
  15 --?   print('==')
  16
  17   love.timer.step()
  18   local dt = 0
  19
  20   return function()
  21     if love.event then
  22       love.event.pump()
  23       for name, a,b,c,d,e,f in love.event.poll() do
  24         if name == "quit" then
  25           if not love.quit or not love.quit() then
  26             return a or 0
  27           end
  28         end
  29         xpcall(function() love.handlers[name](a,b,c,d,e,f) end, handle_error)
  30       end
  31     end
  32
  33     dt = love.timer.step()
  34     xpcall(function() App.update(dt) end, handle_error)
  35
  36     love.graphics.origin()
  37     love.graphics.clear(love.graphics.getBackgroundColor())
  38     xpcall(App.draw, handle_error)
  39     love.graphics.present()
  40
  41     love.timer.sleep(0.001)
  42   end
  43 end
  44
  45 function handle_error(err)
  46   local callstack = debug.traceback('', --[[stack frame]]2)
  47   Error_message = 'Error: ' .. tostring(err)..'\n'..cleaned_up_callstack(callstack)
  48   print(Error_message)
  49   if Current_app == 'run' then
  50     Settings.current_app = 'source'
  51     love.filesystem.write('config', json.encode(Settings))
  52     load_file_from_source_or_save_directory('main.lua')
  53     App.undo_initialize()
  54     App.run_tests_and_initialize()
  55   else
  56     -- abort without running love.quit handler
  57     Disable_all_quit_handlers = true
  58     love.event.quit()
  59   end
  60 end
  61
  62 -- I tend to read code from files myself (say using love.filesystem calls)
  63 -- rather than offload that to load().
  64 -- Functions compiled in this manner have ugly filenames of the form [string "filename"]
  65 -- This function cleans out this cruft from error callstacks.
  66 function cleaned_up_callstack(callstack)
  67   local frames = {}
  68   for frame in string.gmatch(callstack, '[^\n]+\n*') do
  69     local line = frame:gsub('^%s*(.-)\n?$', '%1')
  70     local filename, rest = line:match('([^:]*):(.*)')
  71     local core_filename = filename:match('^%[string "(.*)"%]$')
  72     -- pass through frames that don't match this format
  73     -- this includes the initial line "stack traceback:"
  74     local new_frame = (core_filename or filename)..':'..rest
  75     table.insert(frames, new_frame)
  76   end
  77   -- the initial "stack traceback:" line was unindented and remains so
  78   return table.concat(frames, '\n\t')
  79 end
  80
  81 -- The rest of this file wraps around various LÖVE primitives to support
  82 -- automated tests. Often tests will run with a fake version of a primitive
  83 -- that redirects to the real love.* version once we're done with tests.
  84 --
  85 -- Not everything is so wrapped yet. Sometimes you still have to use love.*
  86 -- primitives directly.
  87
  88 App = {}
  89
  90 function App.love_version()
  91   local major_version, minor_version = love.getVersion()
  92   local version = major_version..'.'..minor_version
  93   return version, major_version
  94 end
  95
  96 -- save/restore various framework globals we care about -- only on very first load
  97 function App.snapshot_love()
  98   if Love_snapshot then return end
  99   Love_snapshot = {}
 100   -- save the entire initial font; it doesn't seem reliably recreated using newFont
 101   Love_snapshot.initial_font = love.graphics.getFont()
 102 end
 103
 104 function App.undo_initialize()
 105   love.graphics.setFont(Love_snapshot.initial_font)
 106 end
 107
 108 function App.run_tests_and_initialize()
 109   App.load()
 110   Test_errors = {}
 111   App.run_tests()
 112   if #Test_errors > 0 then
 113     local error_message = ''
 114     if Warning_before_tests then
 115       error_message = Warning_before_tests..'\n\n'
 116     end
 117     error_message = error_message .. ('There were %d test failures:\n%s'):format(#Test_errors, table.concat(Test_errors))
 118     error(error_message)
 119   end
 120   App.disable_tests()
 121   App.initialize_globals()
 122   App.initialize(love.arg.parseGameArguments(arg), arg)
 123 end
 124
 125 function App.run_tests()
 126   local sorted_names = {}
 127   for name,binding in pairs(_G) do
 128     if name:find('test_') == 1 then
 129       table.insert(sorted_names, name)
 130     end
 131   end
 132   table.sort(sorted_names)
 133   for _,name in ipairs(sorted_names) do
 134     App.initialize_for_test()
 135 --?     print('=== '..name)
 136 --?     _G[name]()
 137     xpcall(_G[name], function(err) prepend_debug_info_to_test_failure(name, err) end)
 138   end
 139   -- clean up all test methods
 140   for _,name in ipairs(sorted_names) do
 141     _G[name] = nil
 142   end
 143 end
 144
 145 function App.initialize_for_test()
 146   App.screen.init{width=100, height=50}
 147   App.screen.contents = {}  -- clear screen
 148   App.filesystem = {}
 149   App.source_dir = ''
 150   App.current_dir = ''
 151   App.save_dir = ''
 152   App.fake_keys_pressed = {}
 153   App.fake_mouse_state = {x=-1, y=-1}
 154   App.initialize_globals()
 155 end
 156
 157 -- App.screen.resize and App.screen.move seem like better names than
 158 -- love.window.setMode and love.window.setPosition respectively. They'll
 159 -- be side-effect-free during tests, and they'll save their results in
 160 -- attributes of App.screen for easy access.
 161
 162 App.screen={}
 163
 164 -- Use App.screen.init in tests to initialize the fake screen.
 165 function App.screen.init(dims)
 166   App.screen.width = dims.width
 167   App.screen.height = dims.height
 168 end
 169
 170 function App.screen.resize(width, height, flags)
 171   App.screen.width = width
 172   App.screen.height = height
 173   App.screen.flags = flags
 174 end
 175
 176 function App.screen.size()
 177   return App.screen.width, App.screen.height, App.screen.flags
 178 end
 179
 180 function App.screen.move(x,y, displayindex)
 181   App.screen.x = x
 182   App.screen.y = y
 183   App.screen.displayindex = displayindex
 184 end
 185
 186 function App.screen.position()
 187   return App.screen.x, App.screen.y, App.screen.displayindex
 188 end
 189
 190 -- If you use App.screen.print instead of love.graphics.print,
 191 -- tests will be able to check what was printed using App.screen.check below.
 192 --
 193 -- One drawback of this approach: the y coordinate used depends on font size,
 194 -- which feels brittle.
 195
 196 function App.screen.print(msg, x,y)
 197   local screen_row = 'y'..tostring(y)
 198 --?   print('drawing "'..msg..'" at y '..tostring(y))
 199   local screen = App.screen
 200   if screen.contents[screen_row] == nil then
 201     screen.contents[screen_row] = {}
 202     for i=0,screen.width-1 do
 203       screen.contents[screen_row][i] = ''
 204     end
 205   end
 206   if x < screen.width then
 207     screen.contents[screen_row][x] = msg
 208   end
 209 end
 210
 211 function App.screen.check(y, expected_contents, msg)
 212 --?   print('checking for "'..expected_contents..'" at y '..tostring(y))
 213   local screen_row = 'y'..tostring(y)
 214   local contents = ''
 215   if App.screen.contents[screen_row] == nil then
 216     error('no text at y '..tostring(y))
 217   end
 218   for i,s in ipairs(App.screen.contents[screen_row]) do
 219     contents = contents..s
 220   end
 221   check_eq(contents, expected_contents, msg)
 222 end
 223
 224 -- If you access the time using App.get_time instead of love.timer.getTime,
 225 -- tests will be able to move the time back and forwards as needed using
 226 -- App.wait_fake_time below.
 227
 228 App.time = 1
 229 function App.get_time()
 230   return App.time
 231 end
 232 function App.wait_fake_time(t)
 233   App.time = App.time + t
 234 end
 235
 236 function App.width(text)
 237   return love.graphics.getFont():getWidth(text)
 238 end
 239
 240 -- If you access the clipboard using App.get_clipboard and App.set_clipboard
 241 -- instead of love.system.getClipboardText and love.system.setClipboardText
 242 -- respectively, tests will be able to manipulate the clipboard by
 243 -- reading/writing App.clipboard.
 244
 245 App.clipboard = ''
 246 function App.get_clipboard()
 247   return App.clipboard
 248 end
 249 function App.set_clipboard(s)
 250   App.clipboard = s
 251 end
 252
 253 -- In tests I mostly send chords all at once to the keyboard handlers.
 254 -- However, you'll occasionally need to check if a key is down outside a handler.
 255 -- If you use App.key_down instead of love.keyboard.isDown, tests will be able to
 256 -- simulate keypresses using App.fake_key_press and App.fake_key_release
 257 -- below. This isn't very realistic, though, and it's up to tests to
 258 -- orchestrate key presses that correspond to the handlers they invoke.
 259
 260 App.fake_keys_pressed = {}
 261 function App.key_down(key)
 262   return App.fake_keys_pressed[key]
 263 end
 264
 265 function App.fake_key_press(key)
 266   App.fake_keys_pressed[key] = true
 267 end
 268 function App.fake_key_release(key)
 269   App.fake_keys_pressed[key] = nil
 270 end
 271
 272 -- Tests mostly will invoke mouse handlers directly. However, you'll
 273 -- occasionally need to check if a mouse button is down outside a handler.
 274 -- If you use App.mouse_down instead of love.mouse.isDown, tests will be able to
 275 -- simulate mouse clicks using App.fake_mouse_press and App.fake_mouse_release
 276 -- below. This isn't very realistic, though, and it's up to tests to
 277 -- orchestrate presses that correspond to the handlers they invoke.
 278
 279 App.fake_mouse_state = {x=-1, y=-1}  -- x,y always set
 280
 281 function App.mouse_move(x,y)
 282   App.fake_mouse_state.x = x
 283   App.fake_mouse_state.y = y
 284 end
 285 function App.mouse_down(mouse_button)
 286   return App.fake_mouse_state[mouse_button]
 287 end
 288 function App.mouse_x()
 289   return App.fake_mouse_state.x
 290 end
 291 function App.mouse_y()
 292   return App.fake_mouse_state.y
 293 end
 294
 295 function App.fake_mouse_press(x,y, mouse_button)
 296   App.fake_mouse_state.x = x
 297   App.fake_mouse_state.y = y
 298   App.fake_mouse_state[mouse_button] = true
 299 end
 300 function App.fake_mouse_release(x,y, mouse_button)
 301   App.fake_mouse_state.x = x
 302   App.fake_mouse_state.y = y
 303   App.fake_mouse_state[mouse_button] = nil
 304 end
 305
 306 -- If you use App.open_for_reading and App.open_for_writing instead of other
 307 -- various Lua and LÖVE helpers, tests will be able to check the results of
 308 -- file operations inside the App.filesystem table.
 309
 310 function App.open_for_reading(filename)
 311   if App.filesystem[filename] then
 312     return {
 313       lines = function(self)
 314                 return App.filesystem[filename]:gmatch('[^\n]+')
 315               end,
 316       read = function(self)
 317                return App.filesystem[filename]
 318              end,
 319       close = function(self)
 320               end,
 321     }
 322   end
 323 end
 324
 325 function App.read_file(filename)
 326   return App.filesystem[filename]
 327 end
 328
 329 function App.open_for_writing(filename)
 330   App.filesystem[filename] = ''
 331   return {
 332     write = function(self, s)
 333               App.filesystem[filename] = App.filesystem[filename]..s
 334             end,
 335     close = function(self)
 336             end,
 337   }
 338 end
 339
 340 function App.write_file(filename, contents)
 341   App.filesystem[filename] = contents
 342   return --[[status]] true
 343 end
 344
 345 function App.mkdir(dirname)
 346   -- nothing in test mode
 347 end
 348
 349 function App.remove(filename)
 350   App.filesystem[filename] = nil
 351 end
 352
 353 -- Some helpers to trigger an event and then refresh the screen. Akin to one
 354 -- iteration of the event loop.
 355
 356 -- all textinput events are also keypresses
 357 -- TODO: handle chords of multiple keys
 358 function App.run_after_textinput(t)
 359   App.keypressed(t)
 360   App.textinput(t)
 361   App.keyreleased(t)
 362   App.screen.contents = {}
 363   App.draw()
 364 end
 365
 366 -- not all keys are textinput
 367 -- TODO: handle chords of multiple keys
 368 function App.run_after_keychord(chord, key)
 369   App.keychord_press(chord, key)
 370   App.keyreleased(key)
 371   App.screen.contents = {}
 372   App.draw()
 373 end
 374
 375 function App.run_after_mouse_click(x,y, mouse_button)
 376   App.fake_mouse_press(x,y, mouse_button)
 377   App.mousepressed(x,y, mouse_button)
 378   App.fake_mouse_release(x,y, mouse_button)
 379   App.mousereleased(x,y, mouse_button)
 380   App.screen.contents = {}
 381   App.draw()
 382 end
 383
 384 function App.run_after_mouse_press(x,y, mouse_button)
 385   App.fake_mouse_press(x,y, mouse_button)
 386   App.mousepressed(x,y, mouse_button)
 387   App.screen.contents = {}
 388   App.draw()
 389 end
 390
 391 function App.run_after_mouse_release(x,y, mouse_button)
 392   App.fake_mouse_release(x,y, mouse_button)
 393   App.mousereleased(x,y, mouse_button)
 394   App.screen.contents = {}
 395   App.draw()
 396 end
 397
 398 -- miscellaneous internal helpers
 399
 400 function App.color(color)
 401   love.graphics.setColor(color.r, color.g, color.b, color.a)
 402 end
 403
 404 -- prepend file/line/test
 405 function prepend_debug_info_to_test_failure(test_name, err)
 406   local err_without_line_number = err:gsub('^[^:]*:[^:]*: ', '')
 407   local stack_trace = debug.traceback('', --[[stack frame]]5)
 408   local file_and_line_number = stack_trace:gsub('stack traceback:\n', ''):gsub(': .*', '')
 409   local full_error = file_and_line_number..':'..test_name..' -- '..err_without_line_number
 410 --?   local full_error = file_and_line_number..':'..test_name..' -- '..err_without_line_number..'\t\t'..stack_trace:gsub('\n', '\n\t\t')
 411   table.insert(Test_errors, full_error)
 412 end
 413
 414 nativefs = require 'nativefs'
 415
 416 local Keys_down = {}
 417
 418 -- call this once all tests are run
 419 -- can't run any tests after this
 420 function App.disable_tests()
 421   -- have LÖVE delegate all handlers to App if they exist
 422   -- make sure to late-bind handlers like LÖVE's defaults do
 423   for name in pairs(love.handlers) do
 424     if App[name] then
 425       -- love.keyboard.isDown doesn't work on Android, so emulate it using
 426       -- keypressed and keyreleased events
 427       if name == 'keypressed' then
 428         love.handlers[name] = function(key, scancode, isrepeat)
 429                                 Keys_down[key] = true
 430                                 return App.keypressed(key, scancode, isrepeat)
 431                               end
 432       elseif name == 'keyreleased' then
 433         love.handlers[name] = function(key, scancode)
 434                                 Keys_down[key] = nil
 435                                 return App.keyreleased(key, scancode)
 436                               end
 437       else
 438         love.handlers[name] = function(...) App[name](...) end
 439       end
 440     end
 441   end
 442
 443   -- test methods are disallowed outside tests
 444   App.run_tests = nil
 445   App.disable_tests = nil
 446   App.screen.init = nil
 447   App.filesystem = nil
 448   App.time = nil
 449   App.run_after_textinput = nil
 450   App.run_after_keychord = nil
 451   App.keypress = nil
 452   App.keyrelease = nil
 453   App.run_after_mouse_click = nil
 454   App.run_after_mouse_press = nil
 455   App.run_after_mouse_release = nil
 456   App.fake_keys_pressed = nil
 457   App.fake_key_press = nil
 458   App.fake_key_release = nil
 459   App.fake_mouse_state = nil
 460   App.fake_mouse_press = nil
 461   App.fake_mouse_release = nil
 462   -- other methods dispatch to real hardware
 463   App.screen.resize = love.window.setMode
 464   App.screen.size = love.window.getMode
 465   App.screen.move = love.window.setPosition
 466   App.screen.position = love.window.getPosition
 467   App.screen.print = love.graphics.print
 468   App.open_for_reading =
 469       function(filename)
 470         local result = nativefs.newFile(filename)
 471         local ok, err = result:open('r')
 472         if ok then
 473           return result
 474         else
 475           return ok, err
 476         end
 477       end
 478   App.read_file =
 479       function(path)
 480         if not is_absolute_path(path) then
 481           return --[[status]] false, 'Please use an unambiguous absolute path.'
 482         end
 483         local f, err = App.open_for_reading(path)
 484         if err then
 485           return --[[status]] false, err
 486         end
 487         local contents = f:read()
 488         f:close()
 489         return contents
 490       end
 491   App.open_for_writing =
 492       function(filename)
 493         local result = nativefs.newFile(filename)
 494         local ok, err = result:open('w')
 495         if ok then
 496           return result
 497         else
 498           return ok, err
 499         end
 500       end
 501   App.write_file =
 502       function(path, contents)
 503         if not is_absolute_path(path) then
 504           return --[[status]] false, 'Please use an unambiguous absolute path.'
 505         end
 506         local f, err = App.open_for_writing(path)
 507         if err then
 508           return --[[status]] false, err
 509         end
 510         f:write(contents)
 511         f:close()
 512         return --[[status]] true
 513       end
 514   App.files = nativefs.getDirectoryItems
 515   App.file_info = nativefs.getInfo
 516   App.mkdir = nativefs.createDirectory
 517   App.remove = nativefs.remove
 518   App.source_dir = love.filesystem.getSource()..'/'  -- '/' should work even on Windows
 519   App.current_dir = nativefs.getWorkingDirectory()..'/'
 520   App.save_dir = love.filesystem.getSaveDirectory()..'/'
 521   App.get_time = love.timer.getTime
 522   App.get_clipboard = love.system.getClipboardText
 523   App.set_clipboard = love.system.setClipboardText
 524   App.key_down = function(key) return Keys_down[key] end
 525   App.mouse_move = love.mouse.setPosition
 526   App.mouse_down = love.mouse.isDown
 527   App.mouse_x = love.mouse.getX
 528   App.mouse_y = love.mouse.getY
 529 end