Application Context Implementation #4
393
src/sys.zig
393
src/sys.zig
@ -61,12 +61,29 @@ pub const EventLoop = opaque {
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/// Internal state of the event loop hidden from the API consumer.
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///
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const Implementation = struct {
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user_prefix: []const u8,
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user_prefix: []u8,
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file_system_semaphore: *ext.SDL_sem,
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file_system_mutex: *ext.SDL_mutex,
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file_system_thread: *ext.SDL_Thread,
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file_system_thread: ?*ext.SDL_Thread,
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file_system_messages: ?*FileSystemMessage = null,
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///
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///
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///
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const InitError = error {
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OutOfSemaphores,
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OutOfMutexes,
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OutOfMemory,
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};
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///
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///
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///
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const StartError = error {
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OutOfThreads,
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AlreadyStarted,
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};
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///
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/// Casts `event_loop` to a [Implementation] reference.
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///
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@ -76,6 +93,181 @@ pub const EventLoop = opaque {
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fn cast(event_loop: *EventLoop) *Implementation {
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return @ptrCast(*Implementation, @alignCast(@alignOf(Implementation), event_loop));
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}
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///
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///
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///
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fn deinit(implementation: *Implementation) void {
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var message = FileSystemMessage{
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.frame = @frame(),
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.request = .exit,
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};
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implementation.enqueueFileSystemMessage(&message);
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{
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var status = @as(c_int, 0);
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// SDL2 defines waiting on a null thread reference as a no-op.
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// https://wiki.libsdl.org/SDL_WaitThread
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ext.SDL_WaitThread(implementation.file_system_thread, &status);
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if (status != 0) {
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// TODO: Error check this.
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}
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}
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ext.SDL_free(implementation.user_prefix.ptr);
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ext.SDL_DestroyMutex(implementation.file_system_mutex);
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ext.SDL_DestroySemaphore(implementation.file_system_semaphore);
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}
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///
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/// Enqueues `message` to the file system message processor of `implementation` to be
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/// processed at a later, non-deterministic point.
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///
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fn enqueueFileSystemMessage(implementation: *Implementation,
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message: *FileSystemMessage) void {
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// TODO: Error check this.
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_ = ext.SDL_LockMutex(implementation.file_system_mutex);
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if (implementation.file_system_messages) |messages| {
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messages.next = message;
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} else {
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implementation.file_system_messages = message;
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}
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// TODO: Error check these.
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_ = ext.SDL_UnlockMutex(implementation.file_system_mutex);
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_ = ext.SDL_SemPost(implementation.file_system_semaphore);
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}
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///
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///
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///
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fn init() InitError!Implementation {
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return Implementation{
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.user_prefix = create_pref_path: {
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const path = ext.SDL_GetPrefPath("ona", "ona") orelse {
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ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
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"Failed to load user path");
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return error.OutOfMemory;
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};
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break: create_pref_path path[0 .. std.mem.len(path)];
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},
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.file_system_semaphore = ext.SDL_CreateSemaphore(0)
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orelse return error.OutOfSemaphores,
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.file_system_mutex = ext.SDL_CreateMutex() orelse return error.OutOfMutexes,
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.file_system_thread = null,
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};
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}
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///
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/// [FileSystemMessage] processing function used by a dedicated worker thread, where `data`
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/// is a type-erased reference to a [EventLoop].
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///
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/// The processor returns `0` if it exited normally or any other value if an erroneous exit
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/// occured.
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///
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fn processFileSystemMessages(data: ?*anyopaque) callconv(.C) c_int {
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const implementation = Implementation.cast(@ptrCast(*EventLoop, data orelse unreachable));
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while (true) {
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while (implementation.file_system_messages) |messages| {
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switch (messages.request) {
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.exit => return 0,
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.log => |*log_request| ext.SDL_LogMessage(ext.SDL_LOG_CATEGORY_APPLICATION,
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@enumToInt(log_request.kind), log_request.message.ptr),
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.open => |*open_request| {
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switch (open_request.file_system_path.file_system) {
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.data => {
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// TODO: Implement
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open_request.result = error.NotFound;
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},
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.user => {
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var path_buffer = std.mem.zeroes([4096]u8);
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var path = stack.Fixed(u8){.buffer = path_buffer[0 .. ]};
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path.pushAll(implementation.user_prefix) catch {
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open_request.result = error.NotFound;
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continue;
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};
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if (!open_request.file_system_path.write(path.writer())) {
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open_request.result = error.NotFound;
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continue;
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}
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if (ext.SDL_RWFromFile(&path_buffer, switch (open_request.mode) {
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.readonly => "rb",
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.overwrite => "wb",
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.append => "ab",
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})) |rw_ops| {
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open_request.result = @ptrCast(*FileAccess, rw_ops);
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} else {
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open_request.result = error.NotFound;
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}
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},
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}
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},
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.close => |*close_request| {
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// TODO: Use this result somehow.
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_ = ext.SDL_RWclose(@ptrCast(*ext.SDL_RWops, @alignCast(
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@alignOf(ext.SDL_RWops), close_request.file_access)));
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},
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.read_file => |read_request| {
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// TODO: Implement.
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_ = read_request;
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},
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.seek_file => |seek_request| {
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// TODO: Implement.
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_ = seek_request;
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},
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.tell_file => |tell_request| {
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// TODO: Implement.
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_ = tell_request;
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},
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}
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resume messages.frame;
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implementation.file_system_messages = messages.next;
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}
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// TODO: Error check this.
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_ = ext.SDL_SemWait(implementation.file_system_semaphore);
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}
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}
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///
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///
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///
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fn start(implementation: *Implementation) StartError!void {
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if (implementation.file_system_thread != null) return error.AlreadyStarted;
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implementation.file_system_thread = ext.SDL_CreateThread(processFileSystemMessages,
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"File System Worker", implementation) orelse {
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ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
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"Failed to create file-system work processor");
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return error.OutOfThreads;
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};
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}
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};
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///
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@ -88,7 +280,7 @@ pub const EventLoop = opaque {
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/// [LogKind.warning] represents a log message which is a warning about a issue that does not
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/// break anything important but is not ideal.
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///
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pub const LogKind = enum(c_int) {
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pub const LogKind = enum(u32) {
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info = ext.SDL_LOG_PRIORITY_INFO,
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debug = ext.SDL_LOG_PRIORITY_DEBUG,
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warning = ext.SDL_LOG_PRIORITY_WARN,
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@ -146,28 +338,7 @@ pub const EventLoop = opaque {
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.request = .{.close = .{.file_access = file_access}},
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};
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suspend event_loop.enqueueFileSystemMessage(&file_system_message);
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}
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///
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/// Enqueues `message` to the file system message processor to be processed at a later, non-
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/// deterministic point.
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///
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fn enqueueFileSystemMessage(event_loop: *EventLoop, message: *FileSystemMessage) void {
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const implementation = Implementation.cast(event_loop);
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// TODO: Error check this.
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_ = ext.SDL_LockMutex(implementation.file_system_mutex);
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if (implementation.file_system_messages) |messages| {
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messages.next = message;
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} else {
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implementation.file_system_messages = message;
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}
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// TODO: Error check these.
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_ = ext.SDL_UnlockMutex(implementation.file_system_mutex);
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_ = ext.SDL_SemPost(implementation.file_system_semaphore);
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suspend Implementation.cast(event_loop).enqueueFileSystemMessage(&file_system_message);
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}
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///
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@ -185,7 +356,7 @@ pub const EventLoop = opaque {
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}},
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};
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suspend event_loop.enqueueFileSystemMessage(&file_system_message);
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suspend Implementation.cast(event_loop).enqueueFileSystemMessage(&file_system_message);
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}
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///
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@ -210,97 +381,11 @@ pub const EventLoop = opaque {
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}},
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};
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suspend event_loop.enqueueFileSystemMessage(&file_system_message);
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suspend Implementation.cast(event_loop).enqueueFileSystemMessage(&file_system_message);
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return file_system_message.request.open.result;
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}
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///
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/// [FileSystemMessage] processing function used by a dedicated worker thread, where `data` is
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/// a type-erased reference to a [EventLoop].
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///
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/// The processor returns `0` if it exited normally or any other value if an erroneous exit
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/// occured.
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///
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fn processFileSystemMessages(data: ?*anyopaque) callconv(.C) c_int {
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const implementation = Implementation.cast(@ptrCast(*EventLoop, data orelse unreachable));
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while (true) {
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while (implementation.file_system_messages) |messages| {
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switch (messages.request) {
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.exit => return 0,
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.log => |*log_request| ext.SDL_LogMessage(ext.SDL_LOG_CATEGORY_APPLICATION,
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@enumToInt(log_request.priority), log_request.message),
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.open => |*open_request| {
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switch (open_request.path.file_system) {
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.data => {
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// TODO: Implement
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open_request.result = error.NotFound;
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},
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.user => {
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var path_buffer = std.mem.zeroes([4096]u8);
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var path = stack.Fixed(u8){.buffer = path_buffer[0 .. ]};
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path.pushAll(implementation.user_prefix) catch {
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open_request.result = error.BadFileSystem;
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continue;
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};
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if (!open_request.path.write(path.writer())) {
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open_request.result = error.NotFound;
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continue;
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}
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if (ext.SDL_RWFromFile(&path_buffer, switch (open_request.mode) {
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.readonly => "rb",
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.overwrite => "wb",
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.append => "ab",
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})) |rw_ops| {
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open_request.result = @ptrCast(*FileAccess, rw_ops);
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} else {
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open_request.result = error.NotFound;
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}
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},
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}
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},
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.close => |*close_request| {
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// TODO: Use this result somehow.
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_ = ext.SDL_RWclose(@ptrCast(*ext.SDL_RWops, @alignCast(
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@alignOf(ext.SDL_RWops), close_request.file_access)));
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},
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.read_file => |read_request| {
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// TODO: Implement.
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_ = read_request;
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},
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.seek_file => |seek_request| {
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// TODO: Implement.
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_ = seek_request;
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},
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.tell_file => |tell_request| {
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// TODO: Implement.
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_ = tell_request;
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},
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}
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resume messages.frame;
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implementation.file_system_messages = messages.next;
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}
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// TODO: Error check this.
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_ = ext.SDL_SemWait(implementation.file_system_semaphore);
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}
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}
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///
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/// Attempts to read the contents of the file referenced by `file_access` at the current file
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/// cursor position into `buffer`.
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@ -320,7 +405,7 @@ pub const EventLoop = opaque {
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}},
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};
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suspend event_loop.enqueueFileSystemMessage(&file_system_message);
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suspend Implementation.cast(event_loop).enqueueFileSystemMessage(&file_system_message);
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return file_system_message.request.read_file.result;
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}
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@ -337,7 +422,7 @@ pub const EventLoop = opaque {
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.request = .{.tell_file = .{.file_access = file_access}},
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};
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suspend event_loop.enqueueFileSystemMessage(&file_system_message);
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suspend Implementation.cast(event_loop).enqueueFileSystemMessage(&file_system_message);
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return file_system_message.request.tell_file.result;
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}
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@ -361,7 +446,7 @@ pub const EventLoop = opaque {
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},
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};
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suspend event_loop.enqueueFileSystemMessage(&file_system_message);
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suspend Implementation.cast(event_loop).enqueueFileSystemMessage(&file_system_message);
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return file_system_message.request.seek_file.result;
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}
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@ -546,18 +631,6 @@ pub fn runGraphics(comptime Errors: anytype, run: GraphicsRunner(Errors)) Errors
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defer ext.SDL_Quit();
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const pref_path = create_pref_path: {
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const path = ext.SDL_GetPrefPath("ona", "ona") orelse {
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ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION, "Failed to load user path");
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return error.InitFailure;
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};
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break: create_pref_path path[0 .. std.mem.len(path)];
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};
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defer ext.SDL_free(pref_path.ptr);
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const window = create_window: {
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const pos = ext.SDL_WINDOWPOS_UNDEFINED;
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var flags = @as(u32, 0);
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@ -583,39 +656,34 @@ pub fn runGraphics(comptime Errors: anytype, run: GraphicsRunner(Errors)) Errors
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defer ext.SDL_DestroyRenderer(renderer);
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var event_loop = EventLoop.Implementation{
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.file_system_semaphore = ext.SDL_CreateSemaphore(0) orelse {
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ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
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"Failed to create file-system work scheduler");
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var event_loop = EventLoop.Implementation.init() catch |err| {
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switch (err) {
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error.OutOfMemory => ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
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"Failed to allocate necessary memory"),
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return error.InitFailure;
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},
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error.OutOfMutexes => ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
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"Failed to create file-system work lock"),
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.file_system_mutex = ext.SDL_CreateMutex() orelse {
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ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
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"Failed to create file-system work lock");
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return error.InitFailure;
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},
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.file_system_thread = unreachable,
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.user_prefix = pref_path,
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};
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event_loop.file_system_thread = ext.SDL_CreateThread(
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EventLoop.processFileSystemMessages, "File System Worker", &event_loop) orelse {
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|
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ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
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"Failed to create file-system work processor");
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error.OutOfSemaphores => ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
|
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"Failed to create file-system work scheduler"),
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}
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||||
|
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return error.InitFailure;
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||||
};
|
||||
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defer {
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ext.SDL_DestroyThread(event_loop.file_system_thread);
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ext.SDL_DestroyMutex(event_loop.file_system_mutex);
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ext.SDL_DestroySemaphore(event_loop.file_system_semaphore);
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}
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defer event_loop.deinit();
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event_loop.start() catch |err| {
|
||||
switch (err) {
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// Not possible for it to have already been started.
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error.AlreadyStarted => unreachable,
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error.OutOfThreads => ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
|
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"Failed to start file-system work processor"),
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}
|
||||
|
||||
return error.InitFailure;
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||||
};
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||||
|
||||
var graphics_context = GraphicsContext.Implementation{
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||||
.event = .{
|
||||
@ -623,20 +691,5 @@ pub fn runGraphics(comptime Errors: anytype, run: GraphicsRunner(Errors)) Errors
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||||
},
|
||||
};
|
||||
|
||||
var message = EventLoop.FileSystemMessage{
|
||||
.frame = @frame(),
|
||||
.request = .exit,
|
||||
};
|
||||
|
||||
@ptrCast(*EventLoop, event_loop).enqueueFileSystemMessage(&message);
|
||||
|
||||
var status = @as(c_int, 0);
|
||||
|
||||
ext.SDL_WaitThread(event_loop.file_system_thread, &status);
|
||||
|
||||
if (status != 0) {
|
||||
// TODO: Error check this.
|
||||
}
|
||||
|
||||
return run(@ptrCast(*EventLoop, &event_loop), @ptrCast(*GraphicsContext, &graphics_context));
|
||||
}
|
||||
|
||||
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