add: signal handling WINCH, user input thread with waiting blocking

src/app.zig

@@ -1,11 +1,11 @@
 //! Application type for TUI-applications
 const std = @import("std");
 const terminal = @import("terminal.zig");
-const code_point = terminal.code_point;
+
 const mergeTaggedUnions = @import("event.zig").mergeTaggedUnions;
 const isTaggedUnion = @import("event.zig").isTaggedUnion;
 
-const BuiltinEvent = @import("event.zig").BuiltinEvent;
+const SystemEvent = @import("event.zig").SystemEvent;
 const Queue = @import("queue.zig").Queue;
 
 const log = std.log.scoped(.app);
@@ -18,25 +18,40 @@ pub fn App(comptime E: type) type {
         @compileError("Provided user event `E` for `App(comptime E: type)` is not of type `union(enum)`.");
     }
     return struct {
-        pub const Event = mergeTaggedUnions(BuiltinEvent, E);
+        pub const Event = mergeTaggedUnions(SystemEvent, E);
         pub const Layout = @import("layout.zig").Layout(Event);
         pub const Widget = @import("widget.zig").Widget(Event);
 
         queue: Queue(Event, 256) = .{},
         thread: ?std.Thread = null,
-        quit: bool = false,
+        quit: std.Thread.ResetEvent = .{},
         termios: ?std.posix.termios = null,
 
-        // TODO: event loop function?
+        pub const SignalHandler = struct {
-        // layout handling?
+            context: *anyopaque,
+            callback: *const fn (context: *anyopaque) void,
+        };
 
         pub fn init() @This() {
+            var winch_act = std.posix.Sigaction{
+                .handler = .{ .handler = @This().handleWinch },
+                .mask = std.posix.empty_sigset,
+                .flags = 0,
+            };
+            std.posix.sigaction(std.posix.SIG.WINCH, &winch_act, null) catch @panic("could not attach signal WINCH");
+
             return .{};
         }
 
         pub fn start(this: *@This()) !void {
             if (this.thread) |_| return;
 
+            try registerWinch(.{
+                .context = this,
+                .callback = @This().winsizeCallback,
+            });
+
+            this.quit.reset();
             this.thread = try std.Thread.spawn(.{}, @This().run, .{this});
             var termios: std.posix.termios = undefined;
             try terminal.enableRawMode(&termios);
@@ -49,7 +64,7 @@ pub fn App(comptime E: type) type {
                 try terminal.disableRawMode(termios);
                 try terminal.restoreScreen();
             }
-            this.quit = true;
+            this.quit.set();
             if (this.thread) |thread| {
                 thread.join();
                 this.thread = null;
@@ -66,16 +81,37 @@ pub fn App(comptime E: type) type {
             this.queue.push(event);
         }
 
+        fn winsizeCallback(ptr: *anyopaque) void {
+            const this: *@This() = @ptrCast(@alignCast(ptr));
+            this.postEvent(.{ .resize = terminal.getTerminalSize() });
+        }
+
+        var winch_handler: ?SignalHandler = null;
+
+        fn registerWinch(handler: SignalHandler) !void {
+            if (winch_handler) |_| {
+                @panic("Cannot register another WINCH handler.");
+            }
+            winch_handler = handler;
+        }
+
+        fn handleWinch(_: c_int) callconv(.C) void {
+            if (winch_handler) |handler| {
+                handler.callback(handler.context);
+            }
+        }
+
         fn run(this: *@This()) !void {
-            // thread to read user inputs
+            // send initial terminal size
+            // changes are handled by the winch signal handler (see `init` and `registerWinch`)
             const size = terminal.getTerminalSize();
             this.postEvent(.{ .resize = size });
-            // read input in loop
+
+            // thread to read user inputs
             var buf: [256]u8 = undefined;
-            while (!this.quit) {
+            while (true) {
-                // FIXME: here is a race-condition -> i.e. there could be events
+                // FIX: I still think that there is a race condition (I'm just waiting 'long' enough)
-                // in the queue, but they will not be executed because the main
+                this.quit.timedWait(20 * std.time.ns_per_ms) catch {
-                // loop will close!
                     const read_bytes = try terminal.read(buf[0..]);
                     // escape key presses
                     if (buf[0] == 0x1b and read_bytes > 1) {
@@ -97,7 +133,7 @@ pub fn App(comptime E: type) type {
                             },
                             0x7f => .{ .cp = terminal.Key.backspace },
                             else => {
-                            var iter = code_point.Iterator{ .bytes = buf[0..read_bytes] };
+                                var iter = terminal.code_point.Iterator{ .bytes = buf[0..read_bytes] };
                                 while (iter.next()) |cp| {
                                     this.postEvent(.{ .key = .{ .cp = cp.code } });
                                 }
@@ -106,6 +142,9 @@ pub fn App(comptime E: type) type {
                         };
                         this.postEvent(.{ .key = key });
                     }
+                    continue;
+                };
+                break;
             }
             this.postEvent(.quit);
         }

src/event.zig

@@ -3,27 +3,19 @@
 const std = @import("std");
 const terminal = @import("terminal.zig");
 
-// Application events which contain information about default application
+pub const Error = struct {
-// parameter. Either `none` or `err`, where `none` represents no event with no
+    err: anyerror,
-// message, while `err` represents an error which is propagated. `Widget`s or
+    msg: []const u8,
-// `Layout`s may react to the event but should continue throwing the message up
-// to the application event loop.
-const ApplicationEvent = union(enum) {
-    none,
-    quit,
-    err: []const u8,
 };
 
-// System events which contain information about events triggered from outside
+// System events available to every application.
-// of the application which impact the application. E.g. the terminal window
+pub const SystemEvent = union(enum) {
-// size has changed, etc.
+    quit,
-const SystemEvent = union(enum) {
+    err: Error,
     resize: terminal.Size,
     key: terminal.Key,
 };
 
-pub const BuiltinEvent = mergeTaggedUnions(SystemEvent, ApplicationEvent);
-
 pub fn mergeTaggedUnions(comptime A: type, comptime B: type) type {
     if (!isTaggedUnion(A) or !isTaggedUnion(B)) {
         @compileError("Both types for merging tagged unions need to be of type `union(enum)`.");

src/layout.zig

@@ -12,10 +12,10 @@
 //! widgets when deallocated. This means that `deinit()` will also deallocate
 //! every used widget too.
 const std = @import("std");
-const lib_event = @import("event.zig");
+const isTaggedUnion = @import("event.zig").isTaggedUnion;
 
 pub fn Layout(comptime Event: type) type {
-    if (!lib_event.isTaggedUnion(Event)) {
+    if (!isTaggedUnion(Event)) {
         @compileError("Provided user event `Event` for `Layout(comptime Event: type)` is not of type `union(enum)`.");
     }
     return struct {
@@ -31,12 +31,12 @@ pub fn Layout(comptime Event: type) type {
         object: Ptr = undefined,
         vtable: *const VTable = undefined,
 
-        // Handle the provided `Event` for this `Widget`.
+        // Handle the provided `Event` for this `Layout`.
         pub fn handle(this: *LayoutType, event: Event) !*std.ArrayList(Event) {
             return try this.vtable.handle(this, event);
         }
 
-        // Return the entire content of this `Widget`.
+        // Return the entire content of this `Layout`.
         pub fn content(this: *LayoutType) !*std.ArrayList(u8) {
             return try this.vtable.content(this);
         }
@@ -51,14 +51,14 @@ pub fn Layout(comptime Event: type) type {
                 .object = @intFromPtr(object),
                 .vtable = &.{
                     .handle = struct {
-                        // Handle the provided `Event` for this `Widget`.
+                        // Handle the provided `Event` for this `Layout`.
                         fn handle(this: *LayoutType, event: Event) !*std.ArrayList(Event) {
                             const layout: @TypeOf(object) = @ptrFromInt(this.object);
                             return try layout.handle(event);
                         }
                     }.handle,
                     .content = struct {
-                        // Return the entire content of this `Widget`.
+                        // Return the entire content of this `Layout`.
                         fn content(this: *LayoutType) !*std.ArrayList(u8) {
                             const layout: @TypeOf(object) = @ptrFromInt(this.object);
                             return try layout.content();

src/layout/Pane.zig

@@ -1,26 +1,27 @@
 const std = @import("std");
-const lib_event = @import("../event.zig");
+const isTaggedUnion = @import("../event.zig").isTaggedUnion;
-const widget = @import("../widget.zig");
+const Error = @import("../event.zig").Error;
 
 pub fn Layout(comptime Event: type) type {
-    if (!lib_event.isTaggedUnion(Event)) {
+    if (!isTaggedUnion(Event)) {
         @compileError("Provided user event `Event` for `Layout(comptime Event: type)` is not of type `union(enum)`.");
     }
+    const Widget = @import("../widget.zig").Widget(Event);
     return struct {
-        w: widget.Widget(Event) = undefined,
+        widget: Widget = undefined,
         events: std.ArrayList(Event) = undefined,
         c: std.ArrayList(u8) = undefined,
 
-        pub fn init(allocator: std.mem.Allocator, w: widget.Widget(Event)) @This() {
+        pub fn init(allocator: std.mem.Allocator, widget: Widget) @This() {
             return .{
-                .w = w,
+                .widget = widget,
                 .events = std.ArrayList(Event).init(allocator),
                 .c = std.ArrayList(u8).init(allocator),
             };
         }
 
         pub fn deinit(this: *@This()) void {
-            this.w.deinit();
+            this.widget.deinit();
             this.events.deinit();
             this.c.deinit();
             this.* = undefined;
@@ -28,14 +29,14 @@ pub fn Layout(comptime Event: type) type {
 
         pub fn handle(this: *@This(), event: Event) !*std.ArrayList(Event) {
             this.events.clearRetainingCapacity();
-            if (this.w.handle(event)) |e| {
+            if (this.widget.handle(event)) |e| {
                 try this.events.append(e);
             }
             return &this.events;
         }
 
         pub fn content(this: *@This()) !*std.ArrayList(u8) {
-            const widget_content = try this.w.content();
+            const widget_content = try this.widget.content();
             this.c.clearRetainingCapacity();
             try this.c.appendSlice(widget_content.items);
             return &this.c;

src/main.zig

@@ -5,7 +5,7 @@ const zlog = @import("zlog");
 const App = @import("app.zig").App(union(enum) {});
 
 pub const std_options = zlog.std_options;
-const log = std.log.scoped(.main);
+const log = std.log.scoped(.default);
 
 pub fn main() !void {
     errdefer |err| log.err("Application Error: {any}", .{err});
@@ -39,7 +39,6 @@ pub fn main() !void {
         const event = app.nextEvent();
 
         switch (event) {
-            .none => continue,
             .quit => break,
             .resize => |size| {
                 // NOTE: draw actions should not happen here (still here for testing)
@@ -52,8 +51,9 @@ pub fn main() !void {
             },
             .key => |key| {
                 log.debug("received key: {any}", .{key});
-                if (terminal.Key.matches(key, .{ .cp = 'q' })) {
+                // ctrl+c to quit
-                    app.quit = true; // TODO: who should emit the .quit event?
+                if (terminal.Key.matches(key, .{ .cp = 'c', .mod = .{ .ctrl = true } })) {
+                    app.quit.set();
                 }
             },
             else => {},

src/widget.zig

@@ -11,10 +11,10 @@
 //! Each `Widget` may cache its content and should if the contents will not
 //! change for a long time.
 const std = @import("std");
-const lib_event = @import("event.zig");
+const isTaggedUnion = @import("event.zig").isTaggedUnion;
 
 pub fn Widget(comptime Event: type) type {
-    if (!lib_event.isTaggedUnion(Event)) {
+    if (!isTaggedUnion(Event)) {
         @compileError("Provided user event `Event` for `Layout(comptime Event: type)` is not of type `union(enum)`.");
     }
     return struct {

src/widget/RawText.zig

@@ -1,8 +1,9 @@
 const std = @import("std");
-const lib_event = @import("../event.zig");
+const isTaggedUnion = @import("../event.zig").isTaggedUnion;
+const Error = @import("../event.zig").Error;
 
 pub fn Widget(comptime Event: type) type {
-    if (!lib_event.isTaggedUnion(Event)) {
+    if (!isTaggedUnion(Event)) {
         @compileError("Provided user event `Event` for `Layout(comptime Event: type)` is not of type `union(enum)`.");
     }
     return struct {