feat(app): event line provides entire line contents as a single event; add(event): .cancel event

Introduce `.cancel` event that is fired when the user sends EOF
in *non raw mode* renderings. The event `.line` now sends the
entire line (even if larger than the internal buffer) but requires
now an `Allocator`.

examples/continuous.zig

@@ -133,7 +133,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/demo.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/direct.zig

@@ -77,7 +77,7 @@ pub fn main() !void {
 
     const gpa = allocator.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(gpa, .{}, .{});
     var renderer = zterm.Renderer.Direct.init(gpa);
     defer renderer.deinit();
 
@@ -147,9 +147,10 @@ pub fn main() !void {
 
             // pre event handling
             switch (event) {
-                // NOTE maybe I want to decouple the `key`s from the user input too? i.e. this only makes sense if the output is not echoed!
-                // otherwise just use gnu's `readline`?
+                // NOTE draw the character with the ctrl indication and a newline to make sure the rendering stays consistent
+                .cancel => try renderer.writeCtrlDWithNewline(),
                 .line => |line| {
+                    defer gpa.free(line);
                     log.debug("{s}", .{line});
                 },
                 // NOTE errors could be displayed in another container in case one was received, etc. to provide the user with feedback

examples/elements/alignment.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/elements/button.zig

@@ -82,7 +82,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/elements/input.zig

@@ -65,7 +65,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/elements/progress.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/elements/radio-button.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/elements/scrollable.zig

@@ -65,7 +65,7 @@ pub fn main() !void {
     }
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/elements/selection.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/errors.zig

@@ -97,7 +97,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/layouts/grid.zig

@@ -35,7 +35,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/layouts/horizontal.zig

@@ -35,7 +35,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/layouts/mixed.zig

@@ -35,7 +35,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/layouts/vertical.zig

@@ -35,7 +35,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/styles/palette.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

examples/styles/text.zig

@@ -178,7 +178,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{}, .{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 

src/app.zig

@@ -24,6 +24,7 @@ pub fn App(comptime M: type, comptime E: type) type {
     if (!isStruct(M)) @compileError("Provided model `M` for `App(comptime M: type, comptime E: type)` is not of type `struct`");
     if (!isTaggedUnion(E)) @compileError("Provided user event `E` for `App(comptime M: type, comptime E: type)` is not of type `union(enum)`.");
     return struct {
+        gpa: Allocator,
         io: std.Io,
         model: Model,
         queue: Queue,
@@ -71,8 +72,9 @@ pub fn App(comptime M: type, comptime E: type) type {
             this.postEvent(.resize);
         }
 
-        pub fn init(io: std.Io, model: Model) @This() {
+        pub fn init(gpa: Allocator, io: std.Io, model: Model) @This() {
             return .{
+                .gpa = gpa,
                 .io = io,
                 .model = model,
                 .queue = .{},
@@ -158,7 +160,7 @@ pub fn App(comptime M: type, comptime E: type) type {
             // thread to read user inputs
             var buf: [512]u8 = undefined;
             // NOTE set the `NONBLOCK` option for the stdin file, such that reading is not blocking!
-            {
+            if (this.config.rawMode) {
                 // TODO is there a better way to do this through the `std.Io` interface?
                 var fl_flags = posix.fcntl(posix.STDIN_FILENO, posix.F.GETFL, 0) catch |err| switch (err) {
                     error.FileBusy => unreachable,
@@ -178,7 +180,11 @@ pub fn App(comptime M: type, comptime E: type) type {
                     else => |e| return e,
                 };
             }
+
             var remaining_bytes: usize = 0;
+            var lines: std.ArrayList(u8) = .empty;
+            defer lines.deinit(this.gpa);
+
             while (true) {
                 this.quit_event.timedWait(20 * std.time.ns_per_ms) catch {
                     // non-blocking read
@@ -192,6 +198,12 @@ pub fn App(comptime M: type, comptime E: type) type {
                     } + remaining_bytes;
                     remaining_bytes = 0;
 
+                    if (read_bytes == 0) {
+                        // received <EOF>
+                        this.postEvent(.cancel);
+                        continue;
+                    }
+
                     // escape key presses
                     if (buf[0] == 0x1b and read_bytes > 1) {
                         switch (buf[1]) {
@@ -448,14 +460,23 @@ pub fn App(comptime M: type, comptime E: type) type {
                                 var len = read_bytes;
                                 while (!std.unicode.utf8ValidateSlice(buf[0..len])) len -= 1;
                                 remaining_bytes = read_bytes - len;
+
                                 if (this.config.rawMode) {
                                     var iter: std.unicode.Utf8Iterator = .{ .bytes = buf[0..len], .i = 0 };
                                     while (iter.nextCodepoint()) |cp| this.postEvent(.{ .key = .{ .cp = cp } });
-                                    continue;
+                                } else try lines.appendSlice(this.gpa, buf[0..len]);
+
+                                if (remaining_bytes > 0) {
+                                    @memmove(buf[0..remaining_bytes], buf[len .. len + remaining_bytes]);
                                 } else {
-                                    this.postEvent(.{ .line = buf[0..len] });
-                                    continue;
+                                    if (read_bytes != 512 and buf[len - 1] == '\n') this.postEvent(.{ .line = try lines.toOwnedSlice(this.gpa) });
+                                    // NOTE line did not end with `\n` but with EOF, meaning the user canceled
+                                    if (read_bytes != 512 and buf[len - 1] != '\n') {
+                                        lines.clearRetainingCapacity();
+                                        this.postEvent(.cancel);
                                     }
+                                }
+                                continue; // this switch block does not return a `Key` we continue with loop
                             },
                         };
                         this.postEvent(.{ .key = key });
@@ -509,6 +530,7 @@ const mem = std.mem;
 const fmt = std.fmt;
 const posix = std.posix;
 const Thread = std.Thread;
+const Allocator = mem.Allocator;
 const assert = std.debug.assert;
 const event = @import("event.zig");
 const input = @import("input.zig");

src/event.zig

@@ -8,6 +8,11 @@ pub const SystemEvent = union(enum) {
     init,
     /// Quit event to signify the end of the event loop (rendering should stop afterwards)
     quit,
+    /// Cancel event to signify that the user provided an EOF
+    ///
+    /// Usually this event is only triggered by the system in *non raw mode*
+    /// renderings otherwise the corresponding `.key` event would be fired instead.
+    cancel,
     /// Resize event to signify that the application should re-draw to resize
     ///
     /// Usually no `Container` nor `Element` should act on that event, as it
@@ -23,7 +28,10 @@ pub const SystemEvent = union(enum) {
         /// associated error message
         msg: []const u8,
     },
-    /// Input line event received in non *raw mode* (instead of individual `key` events)
+    /// Input line event received in *non raw mode* (instead of individual `key` events)
+    ///
+    /// This event contains the entire line until the ending newline character
+    /// (which is included in the payload of this event).
     line: []const u8,
     /// Input key event received from the user
     key: Key,

src/render.zig

@@ -158,6 +158,11 @@ pub const Direct = struct {
         try terminal.clearScreen();
     }
 
+    pub fn writeCtrlDWithNewline(this: *@This()) !void {
+        _ = this;
+        _ = try terminal.write("^D\n");
+    }
+
     /// Render provided cells at size (anchor and dimension) into the *screen*.
     pub fn render(this: *@This(), comptime Container: type, container: *Container, comptime Model: type, model: *const Model) !void {
         const size: Point = container.size;