From 6aaedb813fa11ba0679c3051bc2eb28646b9506c Mon Sep 17 00:00:00 2001 From: 3gg <3gg@shellblade.net> Date: Sat, 30 Aug 2025 16:53:58 -0700 Subject: Update to SDL3 --- src/contrib/SDL-3.2.20/include/SDL3/SDL_asyncio.h | 546 ++++++++++++++++++++++ 1 file changed, 546 insertions(+) create mode 100644 src/contrib/SDL-3.2.20/include/SDL3/SDL_asyncio.h (limited to 'src/contrib/SDL-3.2.20/include/SDL3/SDL_asyncio.h') diff --git a/src/contrib/SDL-3.2.20/include/SDL3/SDL_asyncio.h b/src/contrib/SDL-3.2.20/include/SDL3/SDL_asyncio.h new file mode 100644 index 0000000..b36cb07 --- /dev/null +++ b/src/contrib/SDL-3.2.20/include/SDL3/SDL_asyncio.h @@ -0,0 +1,546 @@ +/* + Simple DirectMedia Layer + Copyright (C) 1997-2025 Sam Lantinga + + This software is provided 'as-is', without any express or implied + warranty. In no event will the authors be held liable for any damages + arising from the use of this software. + + Permission is granted to anyone to use this software for any purpose, + including commercial applications, and to alter it and redistribute it + freely, subject to the following restrictions: + + 1. The origin of this software must not be misrepresented; you must not + claim that you wrote the original software. If you use this software + in a product, an acknowledgment in the product documentation would be + appreciated but is not required. + 2. Altered source versions must be plainly marked as such, and must not be + misrepresented as being the original software. + 3. This notice may not be removed or altered from any source distribution. +*/ + +/* WIKI CATEGORY: AsyncIO */ + +/** + * # CategoryAsyncIO + * + * SDL offers a way to perform I/O asynchronously. This allows an app to read + * or write files without waiting for data to actually transfer; the functions + * that request I/O never block while the request is fulfilled. + * + * Instead, the data moves in the background and the app can check for results + * at their leisure. + * + * This is more complicated than just reading and writing files in a + * synchronous way, but it can allow for more efficiency, and never having + * framerate drops as the hard drive catches up, etc. + * + * The general usage pattern for async I/O is: + * + * - Create one or more SDL_AsyncIOQueue objects. + * - Open files with SDL_AsyncIOFromFile. + * - Start I/O tasks to the files with SDL_ReadAsyncIO or SDL_WriteAsyncIO, + * putting those tasks into one of the queues. + * - Later on, use SDL_GetAsyncIOResult on a queue to see if any task is + * finished without blocking. Tasks might finish in any order with success + * or failure. + * - When all your tasks are done, close the file with SDL_CloseAsyncIO. This + * also generates a task, since it might flush data to disk! + * + * This all works, without blocking, in a single thread, but one can also wait + * on a queue in a background thread, sleeping until new results have arrived: + * + * - Call SDL_WaitAsyncIOResult from one or more threads to efficiently block + * until new tasks complete. + * - When shutting down, call SDL_SignalAsyncIOQueue to unblock any sleeping + * threads despite there being no new tasks completed. + * + * And, of course, to match the synchronous SDL_LoadFile, we offer + * SDL_LoadFileAsync as a convenience function. This will handle allocating a + * buffer, slurping in the file data, and null-terminating it; you still check + * for results later. + * + * Behind the scenes, SDL will use newer, efficient APIs on platforms that + * support them: Linux's io_uring and Windows 11's IoRing, for example. If + * those technologies aren't available, SDL will offload the work to a thread + * pool that will manage otherwise-synchronous loads without blocking the app. + * + * ## Best Practices + * + * Simple non-blocking I/O--for an app that just wants to pick up data + * whenever it's ready without losing framerate waiting on disks to spin--can + * use whatever pattern works well for the program. In this case, simply call + * SDL_ReadAsyncIO, or maybe SDL_LoadFileAsync, as needed. Once a frame, call + * SDL_GetAsyncIOResult to check for any completed tasks and deal with the + * data as it arrives. + * + * If two separate pieces of the same program need their own I/O, it is legal + * for each to create their own queue. This will prevent either piece from + * accidentally consuming the other's completed tasks. Each queue does require + * some amount of resources, but it is not an overwhelming cost. Do not make a + * queue for each task, however. It is better to put many tasks into a single + * queue. They will be reported in order of completion, not in the order they + * were submitted, so it doesn't generally matter what order tasks are + * started. + * + * One async I/O queue can be shared by multiple threads, or one thread can + * have more than one queue, but the most efficient way--if ruthless + * efficiency is the goal--is to have one queue per thread, with multiple + * threads working in parallel, and attempt to keep each queue loaded with + * tasks that are both started by and consumed by the same thread. On modern + * platforms that can use newer interfaces, this can keep data flowing as + * efficiently as possible all the way from storage hardware to the app, with + * no contention between threads for access to the same queue. + * + * Written data is not guaranteed to make it to physical media by the time a + * closing task is completed, unless SDL_CloseAsyncIO is called with its + * `flush` parameter set to true, which is to say that a successful result + * here can still result in lost data during an unfortunately-timed power + * outage if not flushed. However, flushing will take longer and may be + * unnecessary, depending on the app's needs. + */ + +#ifndef SDL_asyncio_h_ +#define SDL_asyncio_h_ + +#include + +#include +/* Set up for C function definitions, even when using C++ */ +#ifdef __cplusplus +extern "C" { +#endif + +/** + * The asynchronous I/O operation structure. + * + * This operates as an opaque handle. One can then request read or write + * operations on it. + * + * \since This struct is available since SDL 3.2.0. + * + * \sa SDL_AsyncIOFromFile + */ +typedef struct SDL_AsyncIO SDL_AsyncIO; + +/** + * Types of asynchronous I/O tasks. + * + * \since This enum is available since SDL 3.2.0. + */ +typedef enum SDL_AsyncIOTaskType +{ + SDL_ASYNCIO_TASK_READ, /**< A read operation. */ + SDL_ASYNCIO_TASK_WRITE, /**< A write operation. */ + SDL_ASYNCIO_TASK_CLOSE /**< A close operation. */ +} SDL_AsyncIOTaskType; + +/** + * Possible outcomes of an asynchronous I/O task. + * + * \since This enum is available since SDL 3.2.0. + */ +typedef enum SDL_AsyncIOResult +{ + SDL_ASYNCIO_COMPLETE, /**< request was completed without error */ + SDL_ASYNCIO_FAILURE, /**< request failed for some reason; check SDL_GetError()! */ + SDL_ASYNCIO_CANCELED /**< request was canceled before completing. */ +} SDL_AsyncIOResult; + +/** + * Information about a completed asynchronous I/O request. + * + * \since This struct is available since SDL 3.2.0. + */ +typedef struct SDL_AsyncIOOutcome +{ + SDL_AsyncIO *asyncio; /**< what generated this task. This pointer will be invalid if it was closed! */ + SDL_AsyncIOTaskType type; /**< What sort of task was this? Read, write, etc? */ + SDL_AsyncIOResult result; /**< the result of the work (success, failure, cancellation). */ + void *buffer; /**< buffer where data was read/written. */ + Uint64 offset; /**< offset in the SDL_AsyncIO where data was read/written. */ + Uint64 bytes_requested; /**< number of bytes the task was to read/write. */ + Uint64 bytes_transferred; /**< actual number of bytes that were read/written. */ + void *userdata; /**< pointer provided by the app when starting the task */ +} SDL_AsyncIOOutcome; + +/** + * A queue of completed asynchronous I/O tasks. + * + * When starting an asynchronous operation, you specify a queue for the new + * task. A queue can be asked later if any tasks in it have completed, + * allowing an app to manage multiple pending tasks in one place, in whatever + * order they complete. + * + * \since This struct is available since SDL 3.2.0. + * + * \sa SDL_CreateAsyncIOQueue + * \sa SDL_ReadAsyncIO + * \sa SDL_WriteAsyncIO + * \sa SDL_GetAsyncIOResult + * \sa SDL_WaitAsyncIOResult + */ +typedef struct SDL_AsyncIOQueue SDL_AsyncIOQueue; + +/** + * Use this function to create a new SDL_AsyncIO object for reading from + * and/or writing to a named file. + * + * The `mode` string understands the following values: + * + * - "r": Open a file for reading only. It must exist. + * - "w": Open a file for writing only. It will create missing files or + * truncate existing ones. + * - "r+": Open a file for update both reading and writing. The file must + * exist. + * - "w+": Create an empty file for both reading and writing. If a file with + * the same name already exists its content is erased and the file is + * treated as a new empty file. + * + * There is no "b" mode, as there is only "binary" style I/O, and no "a" mode + * for appending, since you specify the position when starting a task. + * + * This function supports Unicode filenames, but they must be encoded in UTF-8 + * format, regardless of the underlying operating system. + * + * This call is _not_ asynchronous; it will open the file before returning, + * under the assumption that doing so is generally a fast operation. Future + * reads and writes to the opened file will be async, however. + * + * \param file a UTF-8 string representing the filename to open. + * \param mode an ASCII string representing the mode to be used for opening + * the file. + * \returns a pointer to the SDL_AsyncIO structure that is created or NULL on + * failure; call SDL_GetError() for more information. + * + * \since This function is available since SDL 3.2.0. + * + * \sa SDL_CloseAsyncIO + * \sa SDL_ReadAsyncIO + * \sa SDL_WriteAsyncIO + */ +extern SDL_DECLSPEC SDL_AsyncIO * SDLCALL SDL_AsyncIOFromFile(const char *file, const char *mode); + +/** + * Use this function to get the size of the data stream in an SDL_AsyncIO. + * + * This call is _not_ asynchronous; it assumes that obtaining this info is a + * non-blocking operation in most reasonable cases. + * + * \param asyncio the SDL_AsyncIO to get the size of the data stream from. + * \returns the size of the data stream in the SDL_IOStream on success or a + * negative error code on failure; call SDL_GetError() for more + * information. + * + * \threadsafety It is safe to call this function from any thread. + * + * \since This function is available since SDL 3.2.0. + */ +extern SDL_DECLSPEC Sint64 SDLCALL SDL_GetAsyncIOSize(SDL_AsyncIO *asyncio); + +/** + * Start an async read. + * + * This function reads up to `size` bytes from `offset` position in the data + * source to the area pointed at by `ptr`. This function may read less bytes + * than requested. + * + * This function returns as quickly as possible; it does not wait for the read + * to complete. On a successful return, this work will continue in the + * background. If the work begins, even failure is asynchronous: a failing + * return value from this function only means the work couldn't start at all. + * + * `ptr` must remain available until the work is done, and may be accessed by + * the system at any time until then. Do not allocate it on the stack, as this + * might take longer than the life of the calling function to complete! + * + * An SDL_AsyncIOQueue must be specified. The newly-created task will be added + * to it when it completes its work. + * + * \param asyncio a pointer to an SDL_AsyncIO structure. + * \param ptr a pointer to a buffer to read data into. + * \param offset the position to start reading in the data source. + * \param size the number of bytes to read from the data source. + * \param queue a queue to add the new SDL_AsyncIO to. + * \param userdata an app-defined pointer that will be provided with the task + * results. + * \returns true on success or false on failure; call SDL_GetError() for more + * information. + * + * \threadsafety It is safe to call this function from any thread. + * + * \since This function is available since SDL 3.2.0. + * + * \sa SDL_WriteAsyncIO + * \sa SDL_CreateAsyncIOQueue + */ +extern SDL_DECLSPEC bool SDLCALL SDL_ReadAsyncIO(SDL_AsyncIO *asyncio, void *ptr, Uint64 offset, Uint64 size, SDL_AsyncIOQueue *queue, void *userdata); + +/** + * Start an async write. + * + * This function writes `size` bytes from `offset` position in the data source + * to the area pointed at by `ptr`. + * + * This function returns as quickly as possible; it does not wait for the + * write to complete. On a successful return, this work will continue in the + * background. If the work begins, even failure is asynchronous: a failing + * return value from this function only means the work couldn't start at all. + * + * `ptr` must remain available until the work is done, and may be accessed by + * the system at any time until then. Do not allocate it on the stack, as this + * might take longer than the life of the calling function to complete! + * + * An SDL_AsyncIOQueue must be specified. The newly-created task will be added + * to it when it completes its work. + * + * \param asyncio a pointer to an SDL_AsyncIO structure. + * \param ptr a pointer to a buffer to write data from. + * \param offset the position to start writing to the data source. + * \param size the number of bytes to write to the data source. + * \param queue a queue to add the new SDL_AsyncIO to. + * \param userdata an app-defined pointer that will be provided with the task + * results. + * \returns true on success or false on failure; call SDL_GetError() for more + * information. + * + * \threadsafety It is safe to call this function from any thread. + * + * \since This function is available since SDL 3.2.0. + * + * \sa SDL_ReadAsyncIO + * \sa SDL_CreateAsyncIOQueue + */ +extern SDL_DECLSPEC bool SDLCALL SDL_WriteAsyncIO(SDL_AsyncIO *asyncio, void *ptr, Uint64 offset, Uint64 size, SDL_AsyncIOQueue *queue, void *userdata); + +/** + * Close and free any allocated resources for an async I/O object. + * + * Closing a file is _also_ an asynchronous task! If a write failure were to + * happen during the closing process, for example, the task results will + * report it as usual. + * + * Closing a file that has been written to does not guarantee the data has + * made it to physical media; it may remain in the operating system's file + * cache, for later writing to disk. This means that a successfully-closed + * file can be lost if the system crashes or loses power in this small window. + * To prevent this, call this function with the `flush` parameter set to true. + * This will make the operation take longer, and perhaps increase system load + * in general, but a successful result guarantees that the data has made it to + * physical storage. Don't use this for temporary files, caches, and + * unimportant data, and definitely use it for crucial irreplaceable files, + * like game saves. + * + * This function guarantees that the close will happen after any other pending + * tasks to `asyncio`, so it's safe to open a file, start several operations, + * close the file immediately, then check for all results later. This function + * will not block until the tasks have completed. + * + * Once this function returns true, `asyncio` is no longer valid, regardless + * of any future outcomes. Any completed tasks might still contain this + * pointer in their SDL_AsyncIOOutcome data, in case the app was using this + * value to track information, but it should not be used again. + * + * If this function returns false, the close wasn't started at all, and it's + * safe to attempt to close again later. + * + * An SDL_AsyncIOQueue must be specified. The newly-created task will be added + * to it when it completes its work. + * + * \param asyncio a pointer to an SDL_AsyncIO structure to close. + * \param flush true if data should sync to disk before the task completes. + * \param queue a queue to add the new SDL_AsyncIO to. + * \param userdata an app-defined pointer that will be provided with the task + * results. + * \returns true on success or false on failure; call SDL_GetError() for more + * information. + * + * \threadsafety It is safe to call this function from any thread, but two + * threads should not attempt to close the same object. + * + * \since This function is available since SDL 3.2.0. + */ +extern SDL_DECLSPEC bool SDLCALL SDL_CloseAsyncIO(SDL_AsyncIO *asyncio, bool flush, SDL_AsyncIOQueue *queue, void *userdata); + +/** + * Create a task queue for tracking multiple I/O operations. + * + * Async I/O operations are assigned to a queue when started. The queue can be + * checked for completed tasks thereafter. + * + * \returns a new task queue object or NULL if there was an error; call + * SDL_GetError() for more information. + * + * \threadsafety It is safe to call this function from any thread. + * + * \since This function is available since SDL 3.2.0. + * + * \sa SDL_DestroyAsyncIOQueue + * \sa SDL_GetAsyncIOResult + * \sa SDL_WaitAsyncIOResult + */ +extern SDL_DECLSPEC SDL_AsyncIOQueue * SDLCALL SDL_CreateAsyncIOQueue(void); + +/** + * Destroy a previously-created async I/O task queue. + * + * If there are still tasks pending for this queue, this call will block until + * those tasks are finished. All those tasks will be deallocated. Their + * results will be lost to the app. + * + * Any pending reads from SDL_LoadFileAsync() that are still in this queue + * will have their buffers deallocated by this function, to prevent a memory + * leak. + * + * Once this function is called, the queue is no longer valid and should not + * be used, including by other threads that might access it while destruction + * is blocking on pending tasks. + * + * Do not destroy a queue that still has threads waiting on it through + * SDL_WaitAsyncIOResult(). You can call SDL_SignalAsyncIOQueue() first to + * unblock those threads, and take measures (such as SDL_WaitThread()) to make + * sure they have finished their wait and won't wait on the queue again. + * + * \param queue the task queue to destroy. + * + * \threadsafety It is safe to call this function from any thread, so long as + * no other thread is waiting on the queue with + * SDL_WaitAsyncIOResult. + * + * \since This function is available since SDL 3.2.0. + */ +extern SDL_DECLSPEC void SDLCALL SDL_DestroyAsyncIOQueue(SDL_AsyncIOQueue *queue); + +/** + * Query an async I/O task queue for completed tasks. + * + * If a task assigned to this queue has finished, this will return true and + * fill in `outcome` with the details of the task. If no task in the queue has + * finished, this function will return false. This function does not block. + * + * If a task has completed, this function will free its resources and the task + * pointer will no longer be valid. The task will be removed from the queue. + * + * It is safe for multiple threads to call this function on the same queue at + * once; a completed task will only go to one of the threads. + * + * \param queue the async I/O task queue to query. + * \param outcome details of a finished task will be written here. May not be + * NULL. + * \returns true if a task has completed, false otherwise. + * + * \threadsafety It is safe to call this function from any thread. + * + * \since This function is available since SDL 3.2.0. + * + * \sa SDL_WaitAsyncIOResult + */ +extern SDL_DECLSPEC bool SDLCALL SDL_GetAsyncIOResult(SDL_AsyncIOQueue *queue, SDL_AsyncIOOutcome *outcome); + +/** + * Block until an async I/O task queue has a completed task. + * + * This function puts the calling thread to sleep until there a task assigned + * to the queue that has finished. + * + * If a task assigned to the queue has finished, this will return true and + * fill in `outcome` with the details of the task. If no task in the queue has + * finished, this function will return false. + * + * If a task has completed, this function will free its resources and the task + * pointer will no longer be valid. The task will be removed from the queue. + * + * It is safe for multiple threads to call this function on the same queue at + * once; a completed task will only go to one of the threads. + * + * Note that by the nature of various platforms, more than one waiting thread + * may wake to handle a single task, but only one will obtain it, so + * `timeoutMS` is a _maximum_ wait time, and this function may return false + * sooner. + * + * This function may return false if there was a system error, the OS + * inadvertently awoke multiple threads, or if SDL_SignalAsyncIOQueue() was + * called to wake up all waiting threads without a finished task. + * + * A timeout can be used to specify a maximum wait time, but rather than + * polling, it is possible to have a timeout of -1 to wait forever, and use + * SDL_SignalAsyncIOQueue() to wake up the waiting threads later. + * + * \param queue the async I/O task queue to wait on. + * \param outcome details of a finished task will be written here. May not be + * NULL. + * \param timeoutMS the maximum time to wait, in milliseconds, or -1 to wait + * indefinitely. + * \returns true if task has completed, false otherwise. + * + * \threadsafety It is safe to call this function from any thread. + * + * \since This function is available since SDL 3.2.0. + * + * \sa SDL_SignalAsyncIOQueue + */ +extern SDL_DECLSPEC bool SDLCALL SDL_WaitAsyncIOResult(SDL_AsyncIOQueue *queue, SDL_AsyncIOOutcome *outcome, Sint32 timeoutMS); + +/** + * Wake up any threads that are blocking in SDL_WaitAsyncIOResult(). + * + * This will unblock any threads that are sleeping in a call to + * SDL_WaitAsyncIOResult for the specified queue, and cause them to return + * from that function. + * + * This can be useful when destroying a queue to make sure nothing is touching + * it indefinitely. In this case, once this call completes, the caller should + * take measures to make sure any previously-blocked threads have returned + * from their wait and will not touch the queue again (perhaps by setting a + * flag to tell the threads to terminate and then using SDL_WaitThread() to + * make sure they've done so). + * + * \param queue the async I/O task queue to signal. + * + * \threadsafety It is safe to call this function from any thread. + * + * \since This function is available since SDL 3.2.0. + * + * \sa SDL_WaitAsyncIOResult + */ +extern SDL_DECLSPEC void SDLCALL SDL_SignalAsyncIOQueue(SDL_AsyncIOQueue *queue); + +/** + * Load all the data from a file path, asynchronously. + * + * This function returns as quickly as possible; it does not wait for the read + * to complete. On a successful return, this work will continue in the + * background. If the work begins, even failure is asynchronous: a failing + * return value from this function only means the work couldn't start at all. + * + * The data is allocated with a zero byte at the end (null terminated) for + * convenience. This extra byte is not included in SDL_AsyncIOOutcome's + * bytes_transferred value. + * + * This function will allocate the buffer to contain the file. It must be + * deallocated by calling SDL_free() on SDL_AsyncIOOutcome's buffer field + * after completion. + * + * An SDL_AsyncIOQueue must be specified. The newly-created task will be added + * to it when it completes its work. + * + * \param file the path to read all available data from. + * \param queue a queue to add the new SDL_AsyncIO to. + * \param userdata an app-defined pointer that will be provided with the task + * results. + * \returns true on success or false on failure; call SDL_GetError() for more + * information. + * + * \since This function is available since SDL 3.2.0. + * + * \sa SDL_LoadFile_IO + */ +extern SDL_DECLSPEC bool SDLCALL SDL_LoadFileAsync(const char *file, SDL_AsyncIOQueue *queue, void *userdata); + +/* Ends C function definitions when using C++ */ +#ifdef __cplusplus +} +#endif +#include + +#endif /* SDL_asyncio_h_ */ -- cgit v1.2.3