fix memory leak and implement stub front end

src/frontend/ncurses.zig

@@ -239,8 +239,7 @@ pub const IO = struct {
     pub fn init(allocator: std.mem.Allocator) !IOInterface {
         _ = locale.setlocale(locale.LC_ALL, "");
 
-        const io_ptr = try allocator.alloc(IO, 1);
-        var io = &io_ptr[0];
+        var io = try allocator.create(IO);
         io.allocator = allocator;
         io.inst = null;
         io.msgs = null;
@@ -292,5 +291,6 @@ pub const IO = struct {
     pub fn deinit(self: *IO) void {
         self.deleteWindows();
         _ = ncurses.endwin();
+        self.allocator.destroy(self);
     }
 };

src/frontend/stub.zig

@@ -0,0 +1,57 @@
+const std = @import("std");
+const Action = @import("../actions.zig").Action;
+const IOInterface = @import("io_interface.zig").IOInterface;
+
+pub const ActionStack = struct {
+    stream: std.ArrayList(Action),
+
+    pub fn init(allocator: std.mem.Allocator) ActionStack {
+        return ActionStack{
+            .stream = std.ArrayList(Action).init(allocator),
+        };
+    }
+
+    pub fn deinit(self: *ActionStack) void {
+        self.stream.deinit();
+    }
+
+    pub fn scheduleAction(self: *ActionStack, action: Action) !void {
+        try self.stream.append(action);
+    }
+
+    pub fn next(self: *ActionStack) ?Action {
+        return self.stream.popOrNull();
+    }
+};
+
+pub const IO = struct {
+    allocator: std.mem.Allocator,
+    as: ActionStack,
+    out_as: ActionStack,
+
+    pub fn displayMessage(self: *IO, str: []const u8) anyerror!void {
+        _ = self;
+        std.log.info("{s}\n", .{str});
+    }
+
+    pub fn waitForTick(self: *IO) anyerror!Action {
+        const a = self.as.next() orelse return error.NoAvailableAction;
+
+        try self.out_as.scheduleAction(a);
+
+        return a;
+    }
+
+    pub fn init(allocator: std.mem.Allocator, as: ActionStack) !IOInterface {
+        var io = try allocator.create(IO);
+        io.allocator = allocator;
+        io.as = as;
+        io.out_as = ActionStack.init(allocator);
+        return IOInterface.init(io);
+    }
+
+    pub fn deinit(self: *IO) void {
+        self.out_as.deinit();
+        self.allocator.destroy(self);
+    }
+};

src/main.zig

@@ -1,38 +1,23 @@
 const std = @import("std");
 const IO = @import("frontend/ncurses.zig").IO;
-const Action = @import("actions.zig").Action;
-
-fn run(allocator: std.mem.Allocator) !void {
-    var io = try IO.init(allocator);
-    defer {
-        io.deinit();
-    }
-
-    try io.displayMessage("Initialized");
-
-    var action = Action.illegal;
-    var tick_count: usize = 0;
-    while (action != Action.exit) {
-        const str = try std.fmt.allocPrint(allocator, "{}", .{tick_count});
-        defer allocator.free(str);
-        try io.displayMessage(str);
-
-        action = try io.waitForTick();
-        switch (action) {
-            Action.tick => {
-                tick_count += 1;
-            },
-            else => {},
-        }
-    }
-}
+const run = @import("run.zig");
 
 pub fn main() u8 {
+    var status: u8 = 0;
+
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     const allocator = gpa.allocator();
-    run(allocator) catch {
-        return 1;
-    };
-
-    return 0;
+    defer {
+        const deinit_status = gpa.deinit();
+        if (deinit_status == .leak) {
+            status = 1;
+        }
+    }
+
+    var io = IO.init(allocator) catch return 1;
+    defer io.deinit();
+
+    run.run(allocator, &io) catch return 1;
+
+    return status;
 }

src/root.zig

@@ -3,8 +3,10 @@ const testing = std.testing;
 
 const component = @import("ecs/component.zig");
 const ecs = @import("ecs/ecs.zig");
+const run = @import("run.zig");
 
 test {
     _ = component;
     _ = ecs;
+    _ = run;
 }

src/run.zig

@@ -0,0 +1,93 @@
+const std = @import("std");
+const stub = @import("frontend/stub.zig");
+const IO = @import("frontend/io_interface.zig").IOInterface;
+const Action = @import("actions.zig").Action;
+
+pub fn run(allocator: std.mem.Allocator, io: *IO) !void {
+    try io.displayMessage("Initialized");
+
+    var action = Action.illegal;
+    var tick_count: usize = 0;
+    while (action != Action.exit) {
+        const str = try std.fmt.allocPrint(allocator, "{}", .{tick_count});
+        defer allocator.free(str);
+        try io.displayMessage(str);
+
+        action = try io.waitForTick();
+        switch (action) {
+            Action.tick => {
+                tick_count += 1;
+            },
+            else => {},
+        }
+    }
+}
+
+test "can run game" {
+    const allocator = std.testing.allocator;
+
+    var as = stub.ActionStack.init(allocator);
+    defer as.deinit();
+
+    var io = try stub.IO.init(allocator, as);
+    defer io.deinit();
+
+    var res: ?anyerror = null;
+    run(allocator, &io) catch |err| {
+        res = err;
+    };
+    try std.testing.expect(res != null);
+    try std.testing.expectEqual(error.NoAvailableAction, res.?);
+}
+
+test "game exits on Action.exit" {
+    const allocator = std.testing.allocator;
+
+    var as = stub.ActionStack.init(allocator);
+    defer as.deinit();
+    try as.scheduleAction(Action.exit);
+
+    var io = try stub.IO.init(allocator, as);
+    defer io.deinit();
+
+    try run(allocator, &io);
+    const io_obj: *const stub.IO = @ptrCast(@alignCast(io.ptr));
+    var actions = io_obj.out_as;
+
+    const act = actions.next().?;
+    try std.testing.expectEqual(Action.exit, act);
+}
+
+test "game processes stream of actions" {
+    const allocator = std.testing.allocator;
+
+    var as = stub.ActionStack.init(allocator);
+    defer as.deinit();
+
+    try as.scheduleAction(Action.exit);
+    try as.scheduleAction(Action.move_right);
+    try as.scheduleAction(Action.move_left);
+    try as.scheduleAction(Action.move_down);
+    try as.scheduleAction(Action.move_up);
+    try as.scheduleAction(Action.tick);
+
+    var io = try stub.IO.init(allocator, as);
+    defer io.deinit();
+
+    try run(allocator, &io);
+    const io_obj: *const stub.IO = @ptrCast(@alignCast(io.ptr));
+    var actions = io_obj.out_as;
+
+    var act = actions.next().?;
+    try std.testing.expectEqual(Action.exit, act);
+    act = actions.next().?;
+    try std.testing.expectEqual(Action.move_right, act);
+    act = actions.next().?;
+    try std.testing.expectEqual(Action.move_left, act);
+    act = actions.next().?;
+    try std.testing.expectEqual(Action.move_down, act);
+    act = actions.next().?;
+    try std.testing.expectEqual(Action.move_up, act);
+    act = actions.next().?;
+    try std.testing.expectEqual(Action.tick, act);
+}