This replaces the internal mutex with a semaphore, so we're only using a
single synchronization primitive to implement this, and cleans up some logic
around wait timeouts.
This now matches the logic of the originally cited work, from BeOS.
Fixes#3639.
(I think.)
We should wait for the state to stabilize before SDL_ShouldQuit() returns.
For example:
Thread A initializes and increments a use refcount
Thread B skips initializing and increments the use refcount
Thread B starts cleaning up and checks the use refcount
Thread A starts cleaning up, returns because SDL_ShouldQuit() returns false (not initialized), not touching the use refcount
Thread B returns because the use refcount isn't zero
Now we have the state where the refcount is greater than one and both thread A and B have attempted to cleanup.
With this change:
Thread A initializes and increments a use refcount
Thread B skips initializing and increments the use refcount
Thread B starts cleaning up and decrements and checks the use refcount
Thread A starts cleaning up, waits for thread B
Thread B returns because the use refcount isn't zero
Thread A continues and decrements and checks the use refcount, and finishes cleaning up because it has reached 0.
We require stdbool.h in the build environment, so we might as well use the plain bool type.
If your environment doesn't have stdbool.h, this simple replacement will suffice:
typedef signed char bool;
Most SDL functions used to indicate success or failure using an int return code. These functions have been changed to return SDL_bool.
Here is a coccinelle patch to change code that previously compared the return value to 0 and changes it to a boolean test:
@ bool_return_type @
identifier func =~ "^(SDL_AddEventWatch|SDL_AddHintCallback|SDL_AddSurfaceAlternateImage|SDL_AddVulkanRenderSemaphores|SDL_BindAudioStream|SDL_BindAudioStreams|SDL_BlitSurface|SDL_BlitSurface9Grid|SDL_BlitSurfaceScaled|SDL_BlitSurfaceTiled|SDL_BlitSurfaceTiledWithScale|SDL_BlitSurfaceUnchecked|SDL_BlitSurfaceUncheckedScaled|SDL_CaptureMouse|SDL_ClearAudioStream|SDL_ClearClipboardData|SDL_ClearComposition|SDL_ClearError|SDL_ClearProperty|SDL_ClearSurface|SDL_CloseIO|SDL_CloseStorage|SDL_ConvertAudioSamples|SDL_ConvertEventToRenderCoordinates|SDL_ConvertPixels|SDL_ConvertPixelsAndColorspace|SDL_CopyFile|SDL_CopyProperties|SDL_CopyStorageFile|SDL_CreateDirectory|SDL_CreateStorageDirectory|SDL_CreateWindowAndRenderer|SDL_DateTimeToTime|SDL_DestroyWindowSurface|SDL_DetachVirtualJoystick|SDL_DisableScreenSaver|SDL_EnableScreenSaver|SDL_EnumerateDirectory|SDL_EnumerateProperties|SDL_EnumerateStorageDirectory|SDL_FillSurfaceRect|SDL_FillSurfaceRects|SDL_FlashWindow|SDL_FlipSurface|SDL_FlushAudioStream|SDL_FlushRenderer|SDL_GL_DestroyContext|SDL_GL_GetAttribute|SDL_GL_GetSwapInterval|SDL_GL_LoadLibrary|SDL_GL_MakeCurrent|SDL_GL_SetAttribute|SDL_GL_SetSwapInterval|SDL_GL_SwapWindow|SDL_GetAudioDeviceFormat|SDL_GetAudioStreamFormat|SDL_GetCameraFormat|SDL_GetClosestFullscreenDisplayMode|SDL_GetCurrentRenderOutputSize|SDL_GetCurrentTime|SDL_GetDXGIOutputInfo|SDL_GetDateTimeLocalePreferences|SDL_GetDisplayBounds|SDL_GetDisplayUsableBounds|SDL_GetGDKDefaultUser|SDL_GetGDKTaskQueue|SDL_GetGamepadSensorData|SDL_GetGamepadTouchpadFinger|SDL_GetHapticEffectStatus|SDL_GetJoystickBall|SDL_GetMasksForPixelFormat|SDL_GetPathInfo|SDL_GetRectUnion|SDL_GetRectUnionFloat|SDL_GetRenderClipRect|SDL_GetRenderColorScale|SDL_GetRenderDrawBlendMode|SDL_GetRenderDrawColor|SDL_GetRenderDrawColorFloat|SDL_GetRenderLogicalPresentation|SDL_GetRenderLogicalPresentationRect|SDL_GetRenderOutputSize|SDL_GetRenderSafeArea|SDL_GetRenderScale|SDL_GetRenderVSync|SDL_GetRenderViewport|SDL_GetSensorData|SDL_GetStorageFileSize|SDL_GetStoragePathInfo|SDL_GetSurfaceAlphaMod|SDL_GetSurfaceBlendMode|SDL_GetSurfaceClipRect|SDL_GetSurfaceColorKey|SDL_GetSurfaceColorMod|SDL_GetTextInputArea|SDL_GetTextureAlphaMod|SDL_GetTextureAlphaModFloat|SDL_GetTextureBlendMode|SDL_GetTextureColorMod|SDL_GetTextureColorModFloat|SDL_GetTextureScaleMode|SDL_GetTextureSize|SDL_GetWindowAspectRatio|SDL_GetWindowBordersSize|SDL_GetWindowMaximumSize|SDL_GetWindowMinimumSize|SDL_GetWindowPosition|SDL_GetWindowRelativeMouseMode|SDL_GetWindowSafeArea|SDL_GetWindowSize|SDL_GetWindowSizeInPixels|SDL_GetWindowSurfaceVSync|SDL_HideCursor|SDL_HideWindow|SDL_Init|SDL_InitHapticRumble|SDL_InitSubSystem|SDL_LoadWAV|SDL_LoadWAV_IO|SDL_LockAudioStream|SDL_LockProperties|SDL_LockSurface|SDL_LockTexture|SDL_LockTextureToSurface|SDL_MaximizeWindow|SDL_MinimizeWindow|SDL_MixAudio|SDL_OpenURL|SDL_OutOfMemory|SDL_PauseAudioDevice|SDL_PauseAudioStreamDevice|SDL_PauseHaptic|SDL_PlayHapticRumble|SDL_PremultiplyAlpha|SDL_PremultiplySurfaceAlpha|SDL_PushEvent|SDL_PutAudioStreamData|SDL_RaiseWindow|SDL_ReadStorageFile|SDL_ReadSurfacePixel|SDL_ReadSurfacePixelFloat|SDL_RegisterApp|SDL_ReloadGamepadMappings|SDL_RemovePath|SDL_RemoveStoragePath|SDL_RemoveTimer|SDL_RenamePath|SDL_RenameStoragePath|SDL_RenderClear|SDL_RenderCoordinatesFromWindow|SDL_RenderCoordinatesToWindow|SDL_RenderFillRect|SDL_RenderFillRects|SDL_RenderGeometry|SDL_RenderGeometryRaw|SDL_RenderLine|SDL_RenderLines|SDL_RenderPoint|SDL_RenderPoints|SDL_RenderPresent|SDL_RenderRect|SDL_RenderRects|SDL_RenderTexture|SDL_RenderTexture9Grid|SDL_RenderTextureRotated|SDL_RenderTextureTiled|SDL_RequestAndroidPermission|SDL_RestoreWindow|SDL_ResumeAudioDevice|SDL_ResumeAudioStreamDevice|SDL_ResumeHaptic|SDL_RumbleGamepad|SDL_RumbleGamepadTriggers|SDL_RumbleJoystick|SDL_RumbleJoystickTriggers|SDL_RunHapticEffect|SDL_SaveBMP|SDL_SaveBMP_IO|SDL_SendAndroidMessage|SDL_SendGamepadEffect|SDL_SendJoystickEffect|SDL_SendJoystickVirtualSensorData|SDL_SetAppMetadata|SDL_SetAppMetadataProperty|SDL_SetAudioDeviceGain|SDL_SetAudioPostmixCallback|SDL_SetAudioStreamFormat|SDL_SetAudioStreamFrequencyRatio|SDL_SetAudioStreamGain|SDL_SetAudioStreamGetCallback|SDL_SetAudioStreamInputChannelMap|SDL_SetAudioStreamOutputChannelMap|SDL_SetAudioStreamPutCallback|SDL_SetBooleanProperty|SDL_SetClipboardData|SDL_SetClipboardText|SDL_SetCursor|SDL_SetFloatProperty|SDL_SetGamepadLED|SDL_SetGamepadMapping|SDL_SetGamepadPlayerIndex|SDL_SetGamepadSensorEnabled|SDL_SetHapticAutocenter|SDL_SetHapticGain|SDL_SetJoystickLED|SDL_SetJoystickPlayerIndex|SDL_SetJoystickVirtualAxis|SDL_SetJoystickVirtualBall|SDL_SetJoystickVirtualButton|SDL_SetJoystickVirtualHat|SDL_SetJoystickVirtualTouchpad|SDL_SetLinuxThreadPriority|SDL_SetLinuxThreadPriorityAndPolicy|SDL_SetLogPriorityPrefix|SDL_SetMemoryFunctions|SDL_SetNumberProperty|SDL_SetPaletteColors|SDL_SetPointerProperty|SDL_SetPointerPropertyWithCleanup|SDL_SetPrimarySelectionText|SDL_SetRenderClipRect|SDL_SetRenderColorScale|SDL_SetRenderDrawBlendMode|SDL_SetRenderDrawColor|SDL_SetRenderDrawColorFloat|SDL_SetRenderLogicalPresentation|SDL_SetRenderScale|SDL_SetRenderTarget|SDL_SetRenderVSync|SDL_SetRenderViewport|SDL_SetScancodeName|SDL_SetStringProperty|SDL_SetSurfaceAlphaMod|SDL_SetSurfaceBlendMode|SDL_SetSurfaceColorKey|SDL_SetSurfaceColorMod|SDL_SetSurfaceColorspace|SDL_SetSurfacePalette|SDL_SetSurfaceRLE|SDL_SetTLS|SDL_SetTextInputArea|SDL_SetTextureAlphaMod|SDL_SetTextureAlphaModFloat|SDL_SetTextureBlendMode|SDL_SetTextureColorMod|SDL_SetTextureColorModFloat|SDL_SetTextureScaleMode|SDL_SetThreadPriority|SDL_SetWindowAlwaysOnTop|SDL_SetWindowAspectRatio|SDL_SetWindowBordered|SDL_SetWindowFocusable|SDL_SetWindowFullscreen|SDL_SetWindowFullscreenMode|SDL_SetWindowHitTest|SDL_SetWindowIcon|SDL_SetWindowKeyboardGrab|SDL_SetWindowMaximumSize|SDL_SetWindowMinimumSize|SDL_SetWindowModalFor|SDL_SetWindowMouseGrab|SDL_SetWindowMouseRect|SDL_SetWindowOpacity|SDL_SetWindowPosition|SDL_SetWindowRelativeMouseMode|SDL_SetWindowResizable|SDL_SetWindowShape|SDL_SetWindowSize|SDL_SetWindowSurfaceVSync|SDL_SetWindowTitle|SDL_SetiOSAnimationCallback|SDL_ShowAndroidToast|SDL_ShowCursor|SDL_ShowMessageBox|SDL_ShowSimpleMessageBox|SDL_ShowWindow|SDL_ShowWindowSystemMenu|SDL_StartTextInput|SDL_StartTextInputWithProperties|SDL_StopHapticEffect|SDL_StopHapticEffects|SDL_StopHapticRumble|SDL_StopTextInput|SDL_SyncWindow|SDL_TimeToDateTime|SDL_TryLockMutex|SDL_TryLockRWLockForReading|SDL_TryLockRWLockForWriting|SDL_TryWaitSemaphore|SDL_UnlockAudioStream|SDL_UpdateHapticEffect|SDL_UpdateNVTexture|SDL_UpdateTexture|SDL_UpdateWindowSurface|SDL_UpdateWindowSurfaceRects|SDL_UpdateYUVTexture|SDL_Vulkan_CreateSurface|SDL_Vulkan_LoadLibrary|SDL_WaitConditionTimeout|SDL_WaitSemaphoreTimeout|SDL_WarpMouseGlobal|SDL_WriteStorageFile|SDL_WriteSurfacePixel|SDL_WriteSurfacePixelFloat)$";
@@
(
func(
...
)
- == 0
|
- func(
+ !func(
...
)
- < 0
|
- func(
+ !func(
...
)
- != 0
|
- func(
+ !func(
...
)
- == -1
)
This makes the subsystem thread-safe, more performant, and cleans up the code a little.
Also removed SDL_HINT_WINDOWS_FORCE_MUTEX_CRITICAL_SECTIONS, since setting this hint programmatically initializes properties, which creates a lock, so we can't check hints while creating locks. The slim reader-writer locks have been the default for ages and are solid, so we'll just use those when available.
It was intended to make the API easier to use, but various automatic garbage collection all had flaws, and making the application periodically clean up temporary memory added cognitive load to using the API, and in many cases was it was difficult to restructure threaded code to handle this.
So, we're largely going back to the original system, where the API returns allocated results and you free them.
In addition, to solve the problems we originally wanted temporary memory for:
* Short strings with a finite count, like device names, get stored in a per-thread string pool.
* Events continue to use temporary memory internally, which is cleaned up on the next event processing cycle.
This declares that any `const char *` returned from SDL is owned by SDL, and
promises to be valid _at least_ until the next time the event queue runs, or
SDL_Quit() is called, even if the thing that owns the string gets destroyed
or changed before then.
This is noted in the headers as "the SDL_GetStringRule", so this will both be
greppable to find a detailed explaination in docs/README-strings.md and
wikiheaders will automatically turn it into a link we can point at the
appropriate documentation.
Fixes#9902.
(and several FIXMEs, both known and yet-undocumented.)
Otherwise, when you call SDL_CreateCondition() in something that can otherwise
survive in a single-threaded build, you'll get an error that seems fatal.
We already do this for mutexes and rwlocks (but not semaphores!)
Fixes#9558.
Ozkan Sezer
Sasha Szpakowski
Caleb Cornett
Ryan C. Gordon
Sam Lantinga
Anonymous Maarten
Edoardo Lolletti
Mark Delk
Anonymous Maarten
Julian Uy