From c42885bf616fb9f133478e107b8d2ca03789df05 Mon Sep 17 00:00:00 2001
From: kayomn <kayomn@kayomn.net>
Date: Fri, 7 Oct 2022 21:25:49 +0100
Subject: [PATCH] Add stubs for Tar-based file system logic

---
 src/sys.zig | 62 ++++++++++++++++++++++++++++-------------------------
 src/tar.zig | 29 +++++++++++++++++++++++++
 2 files changed, 62 insertions(+), 29 deletions(-)
 create mode 100644 src/tar.zig

diff --git a/src/sys.zig b/src/sys.zig
index 06cd249..1de06ec 100644
--- a/src/sys.zig
+++ b/src/sys.zig
@@ -6,14 +6,14 @@ const io = @import("./io.zig");
 const mem = @import("./mem.zig");
 const stack = @import("./stack.zig");
 const std = @import("std");
+const tar = @import("./tar.zig");
 
 ///
 /// A thread-safe platform abstraction over multiplexing system I/O processing and event handling.
 ///
-pub const EventLoop = opaque {
+pub const App = opaque {
     ///
-    /// Linked list of messages chained together to be processed by the internal file system message
-    /// processor of an [EventLoop].
+    /// Linked list of tasks chained together to be processed by the work processor.
     ///
     const FileSystemMessage = struct {
         next: ?*FileSystemMessage = null,
@@ -34,7 +34,7 @@ pub const EventLoop = opaque {
             open: struct {
                 mode: OpenMode,
                 file_system_path: *const FileSystem.Path,
-                result: OpenError!*FileAccess = error.NotFound,
+                result: OpenError!*FileAccess = error.FileNotFound,
             },
 
             read_file: struct {
@@ -436,11 +436,8 @@ pub const FileSystem = struct {
     ///
     ///
     pub const Root = union(enum) {
-        native: struct {
-            prefix: []const u8,
-        },
-
-        tar: struct {},
+        native: []const u8,
+        archive: *tar.Archive,
 
         ///
         ///
@@ -552,12 +549,12 @@ pub const LogKind = enum(u32) {
 };
 
 ///
-/// [OpenError.NotFound] is a catch-all for when a file could not be located to be opened. This
+/// [OpenError.FileNotFound] 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,
+    FileNotFound,
 };
 
 ///
@@ -625,24 +622,26 @@ pub fn log(kind: LogKind, message: []const u8) void {
 ///
 pub fn open(mode: OpenMode, file_system_path: FileSystem.Path) OpenError!*FileAccess {
     switch (file_system_path.root.*) {
-        .tar => {
+        .archive => |archive| {
             // TODO: Implement.
-            return error.NotFound;
+            _ = archive;
+
+            return error.FileNotFound;
         },
 
         .native => |native| {
             var path_buffer = std.mem.zeroes([4096]u8);
             var path = stack.Fixed(u8){.buffer = path_buffer[0 .. ]};
 
-            path.pushAll(native.prefix) catch return error.NotFound;
+            path.pushAll(native) catch return error.FileNotFound;
 
-            if (file_system_path.write(path.writer())) return error.NotFound;
+            if (file_system_path.write(path.writer())) return error.FileNotFound;
 
             return @ptrCast(?*FileAccess, ext.SDL_RWFromFile(&path_buffer, switch (mode) {
                 .readonly => "rb",
                 .overwrite => "wb",
                 .append => "ab",
-            })) orelse error.NotFound;
+            })) orelse error.FileNotFound;
         },
     }
 }
@@ -650,7 +649,9 @@ pub fn open(mode: OpenMode, file_system_path: FileSystem.Path) OpenError!*FileAc
 ///
 ///
 ///
-pub fn runGraphics(comptime Errors: anytype, comptime run: GraphicsRunner(Errors)) (RunError || Errors)!void {
+pub fn runGraphics(comptime Errors: anytype, allocator: std.mem.Allocator,
+    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");
 
@@ -693,22 +694,25 @@ pub fn runGraphics(comptime Errors: anytype, comptime run: GraphicsRunner(Errors
 
     defer ext.SDL_free(user_prefix);
 
+    var data_archive = tar.Archive.init(allocator);
+
+    data_archive.load("./data.tar") catch |err| switch (err) {
+        error.FileNotFound => {
+
+        },
+    };
+
     var file_system = FileSystem{
-        .user = .{.native = .{.prefix = user_prefix[0 .. std.mem.len(user_prefix)]}},
-        .data = .{.tar = .{}},
+        .user = .{.native = user_prefix[0 .. std.mem.len(user_prefix)]},
+        .data = .{.archive = &data_archive},
     };
 
     var event_loop = EventLoop.Implementation.init() catch |err| {
-        switch (err) {
-            error.OutOfMemory => ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
-                "Failed to allocate necessary memory"),
-
-            error.OutOfMutexes => ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
-                "Failed to create file-system work lock"),
-
-            error.OutOfSemaphores => ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION,
-                "Failed to create file-system work scheduler"),
-        }
+        ext.SDL_LogCritical(ext.SDL_LOG_CATEGORY_APPLICATION, switch (err) {
+            error.OutOfMemory => "Failed to allocate necessary memory",
+            error.OutOfMutexes => "Failed to create file-system work lock",
+            error.OutOfSemaphores => "Failed to create file-system work scheduler",
+        });
 
         return error.InitFailure;
     };
diff --git a/src/tar.zig b/src/tar.zig
new file mode 100644
index 0000000..7adb58e
--- /dev/null
+++ b/src/tar.zig
@@ -0,0 +1,29 @@
+const std = @import("std");
+
+///
+///
+///
+pub const Archive = struct {
+    allocator: std.mem.Allocator,
+
+    pub const LoadError = error {
+        FileNotFound,
+    };
+
+    ///
+    ///
+    ///
+    pub fn init(allocator: std.mem.Allocator) Archive {
+        return Archive{
+            .allocator = allocator,
+        };
+    }
+
+    ///
+    ///
+    ///
+    pub fn load(archive: *Archive, file_path: []const u8) LoadError!void {
+        _ = file_path;
+        _ = archive;
+    }
+};