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