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