Remove global data in file system API

src/main.zig

@@ -21,30 +21,29 @@ test {
     _ = sys;
 }
 
-fn run(event_loop: *sys.EventLoop, graphics: *sys.GraphicsContext) anyerror!void {
+fn run(ev: *sys.EventLoop, fs: *const sys.FileSystem, gr: *sys.GraphicsContext) anyerror!void {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
 
     defer _ = gpa.deinit();
 
     {
-        const file_access = try event_loop.open(.readonly,
+        const file_access = try ev.open(.readonly, try fs.data.joinedPath(&.{"ona.lua"}));
-            try sys.FileSystem.data.joinedPath(&.{"data", "ona.lua"}));
 
-        defer event_loop.close(file_access);
+        defer ev.close(file_access);
 
-        const file_size = try file_access.size(event_loop);
+        const file_size = try file_access.size(ev);
         const allocator = gpa.allocator();
         const buffer = try allocator.alloc(u8, file_size);
 
         defer allocator.free(buffer);
 
-        if ((try event_loop.readFile(file_access, buffer)) != file_size)
+        if ((try ev.readFile(file_access, buffer)) != file_size)
             return error.ScriptLoadFailure;
 
-        event_loop.log(.debug, buffer);
+        ev.log(.debug, buffer);
     }
 
-    while (graphics.poll()) |_| {
+    while (gr.poll()) |_| {
-        graphics.present();
+        gr.present();
     }
 }

src/sys.zig

@@ -61,7 +61,6 @@ pub const EventLoop = opaque {
     /// Internal state of the event loop hidden from the API consumer.
     ///
     const Implementation = struct {
-        user_prefix: []u8,
         file_system_semaphore: *ext.SDL_sem,
         file_system_mutex: *ext.SDL_mutex,
         file_system_thread: ?*ext.SDL_Thread,
@@ -71,6 +70,8 @@ pub const EventLoop = opaque {
         ///
         ///
         const InitError = error {
+            DataFileNotFound,
+            DataFileInvalid,
             OutOfSemaphores,
             OutOfMutexes,
             OutOfMemory,
@@ -147,22 +148,19 @@ pub const EventLoop = opaque {
         ///
         ///
         fn init() InitError!Implementation {
+            const data_file_access = @ptrCast(*FileAccess,
+                ext.SDL_RWFromFile("./data.tar", "r+") orelse return error.DataFileNotFound);
+
             return Implementation{
-                .user_prefix = create_pref_path: {
+                .data_archive = tar.Archive.init(data_file_access) catch |err| switch (err) {
-                    const path = ext.SDL_GetPrefPath("ona", "ona") orelse {
+                    error.Invalid, error.Inaccessible => return error.DataFileInvalid,
-                        ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
-                            "Failed to load user path");
-
-                        return error.OutOfMemory;
-                    };
-
-                    break: create_pref_path path[0 .. std.mem.len(path)];
                 },
 
                 .file_system_semaphore = ext.SDL_CreateSemaphore(0)
                     orelse return error.OutOfSemaphores,
 
                 .file_system_mutex = ext.SDL_CreateMutex() orelse return error.OutOfMutexes,
+                .data_file = data_file_access,
                 .file_system_thread = null,
             };
         }
@@ -181,51 +179,12 @@ pub const EventLoop = opaque {
                 while (implementation.file_system_messages) |messages| {
                     switch (messages.request) {
                         .exit => return 0,
+                        .log => |*log_request| .log(log_request.kind, log_request.message),
 
-                        .log => |*log_request| ext.SDL_LogMessage(ext.SDL_LOG_CATEGORY_APPLICATION,
+                        .open => |*open_request| open_request.result =
-                                    @enumToInt(log_request.kind), log_request.message.ptr),
+                            .open(open_request.mode, open_request.file_system_path),
 
-                        .open => |*open_request| {
+                        .close => |*close_request| .close(close_request.file_access),
-                            switch (open_request.file_system_path.file_system) {
-                                .data => {
-                                    // TODO: Implement
-                                    open_request.result = error.NotFound;
-                                },
-
-                                .user => {
-                                    var path_buffer = std.mem.zeroes([4096]u8);
-                                    var path = stack.Fixed(u8){.buffer = path_buffer[0 .. ]};
-
-                                    path.pushAll(implementation.user_prefix) catch {
-                                        open_request.result = error.NotFound;
-
-                                        continue;
-                                    };
-
-                                    if (!open_request.file_system_path.write(path.writer())) {
-                                        open_request.result = error.NotFound;
-
-                                        continue;
-                                    }
-
-                                    if (ext.SDL_RWFromFile(&path_buffer, switch (open_request.mode) {
-                                        .readonly => "rb",
-                                        .overwrite => "wb",
-                                        .append => "ab",
-                                    })) |rw_ops| {
-                                        open_request.result = @ptrCast(*FileAccess, rw_ops);
-                                    } else {
-                                        open_request.result = error.NotFound;
-                                    }
-                                },
-                            }
-                        },
-
-                        .close => |*close_request| {
-                            // TODO: Use this result somehow.
-                            _ = ext.SDL_RWclose(@ptrCast(*ext.SDL_RWops, @alignCast(
-                                    @alignOf(ext.SDL_RWops), close_request.file_access)));
-                        },
 
                         .read_file => |read_request| {
                             // TODO: Implement.
@@ -270,63 +229,6 @@ pub const EventLoop = opaque {
         }
     };
 
-    ///
-    /// [LogKind.info] represents a log message which is purely informative and does not indicate
-    /// any kind of issue.
-    ///
-    /// [LogKind.debug] represents a log message which is purely for debugging purposes and will
-    /// only occurs in debug builds.
-    ///
-    /// [LogKind.warning] represents a log message which is a warning about a issue that does not
-    /// break anything important but is not ideal.
-    ///
-    pub const LogKind = enum(u32) {
-        info = ext.SDL_LOG_PRIORITY_INFO,
-        debug = ext.SDL_LOG_PRIORITY_DEBUG,
-        warning = ext.SDL_LOG_PRIORITY_WARN,
-    };
-
-    ///
-    /// [OpenError.NotFound] is a catch-all for when a file could not be located to be opened. This
-    /// may be as simple as it doesn't exist or the because the underlying file-system will not /
-    /// cannot give access to it at this time.
-    ///
-    pub const OpenError = error {
-        NotFound,
-    };
-
-    ///
-    /// [OpenMode.readonly] indicates that an existing file is opened in a read-only state,
-    /// disallowing write access.
-    ///
-    /// [OpenMode.overwrite] indicates that an empty file has been created or an existing file has
-    /// been completely overwritten into.
-    ///
-    /// [OpenMode.append] indicates that an existing file that has been opened for reading from and
-    /// writing to on the end of existing data.
-    ///
-    pub const OpenMode = enum {
-        readonly,
-        overwrite,
-        append,
-    };
-
-    ///
-    /// [SeekOrigin.head] indicates that a seek operation will seek from the offset origin of the
-    /// file beginning, or "head".
-    ///
-    /// [SeekOrigin.tail] indicates that a seek operation will seek from the offset origin of the
-    /// file end, or "tail".
-    ///
-    /// [SeekOrigin.cursor] indicates that a seek operation will seek from the current position of
-    /// the file cursor.
-    ///
-    pub const SeekOrigin = enum {
-        head,
-        tail,
-        cursor,
-    };
-
     ///
     /// Closes access to the file referenced by `file_access` via `event_loop`.
     ///
@@ -488,15 +390,15 @@ pub const FileError = error {
 /// Platform-agnostic mechanism for working with an abstraction of the underlying file-system(s)
 /// available to the application in a sandboxed environment.
 ///
-pub const FileSystem = enum {
+pub const FileSystem = struct {
-    data,
+    data: Root,
-    user,
+    user: Root,
 
     ///
     /// Platform-agnostic mechanism for referencing files and directories on a [FileSystem].
     ///
     pub const Path = struct {
-        file_system: FileSystem,
+        root: *const Root,
         length: u16,
         buffer: [max]u8,
 
@@ -521,7 +423,7 @@ pub const FileSystem = enum {
         /// byte. Because of this, it is not safe to asume that a path may hold [max] individual
         /// characters.
         ///
-        pub const max = 1000;
+        pub const max = 512;
 
         ///
         ///
@@ -540,12 +442,17 @@ pub const FileSystem = enum {
     };
 
     ///
-    /// Creates and returns a [Path] value in the file system to the location specified by the
-    /// joining of the `sequences` path values.
     ///
-    pub fn joinedPath(file_system: FileSystem, sequences: []const []const u8) PathError!Path {
+    ///
+    pub const Root = struct {
+        prefix: []const u8,
+
+        ///
+        ///
+        ///
+        pub fn joinedPath(root: Root, sequences: []const []const u8) PathError!Path {
             var path = Path{
-            .file_system = file_system,
+                .root = root,
                 .buffer = std.mem.zeroes([Path.max]u8),
                 .length = 0,
             };
@@ -586,6 +493,7 @@ pub const FileSystem = enum {
 
             return path;
         }
+    };
 };
 
 ///
@@ -629,13 +537,125 @@ pub const GraphicsContext = opaque {
 ///
 ///
 pub fn GraphicsRunner(comptime Errors: type) type {
-    return fn (*EventLoop, *GraphicsContext) callconv(.Async) Errors!void;
+    return fn (*EventLoop, *FileSystem, *GraphicsContext) callconv(.Async) Errors!void;
+}
+
+///
+/// [LogKind.info] represents a log message which is purely informative and does not indicate
+/// any kind of issue.
+///
+/// [LogKind.debug] represents a log message which is purely for debugging purposes and will
+/// only occurs in debug builds.
+///
+/// [LogKind.warning] represents a log message which is a warning about a issue that does not
+/// break anything important but is not ideal.
+///
+pub const LogKind = enum(u32) {
+    info = ext.SDL_LOG_PRIORITY_INFO,
+    debug = ext.SDL_LOG_PRIORITY_DEBUG,
+    warning = ext.SDL_LOG_PRIORITY_WARN,
+};
+
+///
+/// [OpenError.NotFound] is a catch-all for when a file could not be located to be opened. This
+/// may be as simple as it doesn't exist or the because the underlying file-system will not /
+/// cannot give access to it at this time.
+///
+pub const OpenError = error {
+    NotFound,
+};
+
+///
+/// [OpenMode.readonly] indicates that an existing file is opened in a read-only state,
+/// disallowing write access.
+///
+/// [OpenMode.overwrite] indicates that an empty file has been created or an existing file has
+/// been completely overwritten into.
+///
+/// [OpenMode.append] indicates that an existing file that has been opened for reading from and
+/// writing to on the end of existing data.
+///
+pub const OpenMode = enum {
+    readonly,
+    overwrite,
+    append,
+};
+
+///
+///
+///
+pub const RunError = error {
+    InitFailure,
+    AlreadyRunning,
+};
+
+///
+/// [SeekOrigin.head] indicates that a seek operation will seek from the offset origin of the
+/// file beginning, or "head".
+///
+/// [SeekOrigin.tail] indicates that a seek operation will seek from the offset origin of the
+/// file end, or "tail".
+///
+/// [SeekOrigin.cursor] indicates that a seek operation will seek from the current position of
+/// the file cursor.
+///
+pub const SeekOrigin = enum {
+    head,
+    tail,
+    cursor,
+};
+
+///
+///
+///
+pub fn close(file_access: *FileAccess) void {
+    if (!ext.SDL_RWclose(@ptrCast(*ext.SDL_RWops,
+        @alignCast(@alignOf(ext.SDL_RWops), file_access)))) {
+
+        ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
+            "Failed to close file - may have been already closed");
+    }
 }
 
 ///
 ///
 ///
-pub fn runGraphics(comptime Errors: anytype, comptime run: GraphicsRunner(Errors)) Errors!void {
+pub fn log(kind: LogKind, message: []const u8) void {
+    ext.SDL_LogMessage(ext.SDL_LOG_CATEGORY_APPLICATION,
+        @enumToInt(kind), "%.*s", message.len, message.ptr);
+}
+
+///
+///
+///
+pub fn open(mode: OpenMode, file_system_path: FileSystem.Path) OpenError!*FileAccess {
+    switch (file_system_path.file_system) {
+        .data => {
+            // TODO: Implement
+            return error.NotFound;
+        },
+
+        .user => {
+            var path_buffer = std.mem.zeroes([4096]u8);
+            var path = stack.Fixed(u8){.buffer = path_buffer[0 .. ]};
+
+            path.pushAll("/home/kayomn/.local/share") catch return error.NotFound;
+
+            if (file_system_path.write(path.writer())) return error.NotFound;
+
+            return @ptrCast(*FileAccess, ext.SDL_RWFromFile(&path_buffer, switch (mode) {
+                .readonly => "rb",
+                .overwrite => "wb",
+                .append => "ab",
+            })) orelse error.NotFound;
+        },
+    }
+}
+
+///
+///
+///
+pub fn runGraphics(comptime Errors: anytype, comptime run: GraphicsRunner(Errors)) (RunError || Errors)!void {
     if (ext.SDL_Init(ext.SDL_INIT_EVERYTHING) != 0) {
         ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION, "Failed to initialize runtime");
 
@@ -669,6 +689,25 @@ pub fn runGraphics(comptime Errors: anytype, comptime run: GraphicsRunner(Errors
 
     defer ext.SDL_DestroyRenderer(renderer);
 
+    var file_system = FileSystem{
+        .user = .{.prefix = create_pref_path: {
+            const path = ext.SDL_GetPrefPath("ona", "ona") orelse {
+                ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
+                    "Failed to load user path");
+
+                return error.InitFailure;
+            };
+
+            break: create_pref_path path[0 .. std.mem.len(path)];
+        }},
+
+        .data = .{.prefix = "./"},
+    };
+
+    defer {
+        ext.SDL_free(file_system.user.prefix);
+    }
+
     var event_loop = EventLoop.Implementation.init() catch |err| {
         switch (err) {
             error.OutOfMemory => ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,