vaxis: implement hyperlinks (osc8)

This requires additional allocations anytime there is a hyperlink

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>

README.md

@@ -18,7 +18,7 @@ Contributions are welcome.
 | Feature                        | Vaxis | libvaxis | notcurses |
 | ------------------------------ | :---: | :------: | :-------: |
 | RGB                            |  ✅   |    ✅    |    ✅     |
-| Hyperlinks                     |  ✅   | planned  |    ❌     |
+| Hyperlinks                     |  ✅   |    ✅    |    ❌     |
 | Bracketed Paste                |  ✅   |    ✅    |    ❌     |
 | Kitty Keyboard                 |  ✅   |    ✅    |    ✅     |
 | Styled Underlines              |  ✅   |    ✅    |    ✅     |

src/InternalScreen.zig

@@ -11,11 +11,16 @@ const InternalScreen = @This();
 pub const InternalCell = struct {
     char: std.ArrayList(u8) = undefined,
     style: Style = .{},
+    uri: std.ArrayList(u8) = undefined,
+    uri_id: std.ArrayList(u8) = undefined,
     // if we got skipped because of a wide character
     skipped: bool = false,
 
     pub fn eql(self: InternalCell, cell: Cell) bool {
-        return std.mem.eql(u8, self.char.items, cell.char.grapheme) and std.meta.eql(self.style, cell.style);
+        return std.mem.eql(u8, self.char.items, cell.char.grapheme) and
+            std.meta.eql(self.style, cell.style) and
+            std.mem.eql(u8, self.uri.items, cell.link.uri) and
+            std.mem.eql(u8, self.uri_id.items, cell.link.params);
     }
 };
 
@@ -37,6 +42,8 @@ pub fn init(alloc: std.mem.Allocator, w: usize, h: usize) !InternalScreen {
     for (screen.buf, 0..) |_, i| {
         screen.buf[i] = .{
             .char = try std.ArrayList(u8).initCapacity(alloc, 1),
+            .uri = std.ArrayList(u8).init(alloc),
+            .uri_id = std.ArrayList(u8).init(alloc),
         };
     }
     screen.width = w;
@@ -47,6 +54,8 @@ pub fn init(alloc: std.mem.Allocator, w: usize, h: usize) !InternalScreen {
 pub fn deinit(self: *InternalScreen, alloc: std.mem.Allocator) void {
     for (self.buf, 0..) |_, i| {
         self.buf[i].char.deinit();
+        self.buf[i].uri.deinit();
+        self.buf[i].uri_id.deinit();
     }
 
     alloc.free(self.buf);
@@ -57,8 +66,7 @@ pub fn writeCell(
     self: *InternalScreen,
     col: usize,
     row: usize,
-    char: []const u8,
+    cell: Cell,
-    style: Style,
 ) void {
     if (self.width < col) {
         // column out of bounds
@@ -71,8 +79,16 @@ pub fn writeCell(
     const i = (row * self.width) + col;
     assert(i < self.buf.len);
     self.buf[i].char.clearRetainingCapacity();
-    self.buf[i].char.appendSlice(char) catch {
+    self.buf[i].char.appendSlice(cell.char.grapheme) catch {
         log.warn("couldn't write grapheme", .{});
     };
-    self.buf[i].style = style;
+    self.buf[i].uri.clearRetainingCapacity();
+    self.buf[i].uri.appendSlice(cell.link.uri) catch {
+        log.warn("couldn't write uri", .{});
+    };
+    self.buf[i].uri.clearRetainingCapacity();
+    self.buf[i].uri_id.appendSlice(cell.link.params) catch {
+        log.warn("couldn't write uri_id", .{});
+    };
+    self.buf[i].style = cell.style;
 }

src/cell.zig

@@ -1,6 +1,7 @@
 pub const Cell = struct {
     char: Character = .{},
     style: Style = .{},
+    link: Hyperlink = .{},
 };
 
 pub const Character = struct {
@@ -8,6 +9,12 @@ pub const Character = struct {
     width: usize = 1,
 };
 
+pub const Hyperlink = struct {
+    uri: []const u8 = "",
+    /// ie "id=app-1234"
+    params: []const u8 = "",
+};
+
 pub const Style = struct {
     pub const Underline = enum {
         off,
@@ -24,8 +31,6 @@ pub const Style = struct {
     ul_style: Underline = .off,
     // TODO: url should maybe go outside of style. We'll need to allocate these
     // in the internal screen
-    url: ?[]const u8 = null,
-    url_params: ?[]const u8 = null,
 
     bold: bool = false,
     dim: bool = false,

src/vaxis.zig

@@ -11,6 +11,7 @@ const InternalScreen = @import("InternalScreen.zig");
 const Window = @import("Window.zig");
 const Options = @import("Options.zig");
 const Style = @import("cell.zig").Style;
+const Hyperlink = @import("cell.zig").Hyperlink;
 const gwidth = @import("gwidth.zig");
 const Shape = @import("Mouse.zig").Shape;
 
@@ -275,6 +276,7 @@ pub fn Vaxis(comptime T: type) type {
             var row: usize = 0;
             var col: usize = 0;
             var cursor: Style = .{};
+            var link: Hyperlink = .{};
 
             var i: usize = 0;
             while (i < self.screen.buf.len) {
@@ -301,15 +303,18 @@ pub fn Vaxis(comptime T: type) type {
                     reposition = true;
                     // Close any osc8 sequence we might be in before
                     // repositioning
-                    if (cursor.url) |_| {
+                    if (link.uri.len > 0) {
                         _ = try tty.write(ctlseqs.osc8_clear);
                     }
                     continue;
                 }
                 self.screen_last.buf[i].skipped = false;
-                defer cursor = cell.style;
+                defer {
+                    cursor = cell.style;
+                    link = cell.link;
+                }
                 // Set this cell in the last frame
-                self.screen_last.writeCell(col, row, cell.char.grapheme, cell.style);
+                self.screen_last.writeCell(col, row, cell);
 
                 // reposition the cursor, if needed
                 if (reposition) {
@@ -442,16 +447,15 @@ pub fn Vaxis(comptime T: type) type {
                 }
 
                 // url
-                if (!std.meta.eql(cursor.url, cell.style.url)) {
+                if (!std.meta.eql(link.uri, cell.link.uri)) {
-                    const url = cell.style.url orelse "";
+                    var ps = cell.link.params;
-                    var ps = cell.style.url_params orelse "";
+                    if (cell.link.uri.len == 0) {
-                    if (url.len == 0) {
                         // Empty out the params no matter what if we don't have
                         // a url
                         ps = "";
                     }
                     const writer = tty.buffered_writer.writer();
-                    try std.fmt.format(writer, ctlseqs.osc8, .{ ps, url });
+                    try std.fmt.format(writer, ctlseqs.osc8, .{ ps, cell.link.uri });
                 }
                 _ = try tty.write(cell.char.grapheme);
             }