terminal: adjust page capacity for graphemes if necessary

TODO.md

@@ -20,8 +20,3 @@ Major Features:
 
 - Bell
 - Sixels: https://saitoha.github.io/libsixel/
-
-paged-terminal branch:
-
-- tests and logic for overflowing page capacities:
-  - graphemes

src/terminal/Screen.zig

@@ -1033,6 +1033,48 @@ pub fn manualStyleUpdate(self: *Screen) !void {
     self.cursor.style_ref = &md.ref;
 }
 
+/// Append a grapheme to the given cell within the current cursor row.
+pub fn appendGrapheme(self: *Screen, cell: *Cell, cp: u21) !void {
+    self.cursor.page_pin.page.data.appendGrapheme(
+        self.cursor.page_row,
+        cell,
+        cp,
+    ) catch |err| switch (err) {
+        error.OutOfMemory => {
+            // We need to determine the actual cell index of the cell so
+            // that after we adjust the capacity we can reload the cell.
+            const cell_idx: usize = cell_idx: {
+                const cells: [*]Cell = @ptrCast(self.cursor.page_cell);
+                const zero: [*]Cell = cells - self.cursor.x;
+                const target: [*]Cell = @ptrCast(cell);
+                const cell_idx = (@intFromPtr(target) - @intFromPtr(zero)) / @sizeOf(Cell);
+                break :cell_idx cell_idx;
+            };
+
+            // Adjust our capacity. This will update our cursor page pin and
+            // force us to reload.
+            const original_node = self.cursor.page_pin.page;
+            const new_bytes = original_node.data.capacity.grapheme_bytes * 2;
+            _ = try self.pages.adjustCapacity(original_node, .{ .grapheme_bytes = new_bytes });
+            self.cursorReload();
+
+            // The cell pointer is now invalid, so we need to get it from
+            // the reloaded cursor pointers.
+            const reloaded_cell: *Cell = switch (std.math.order(cell_idx, self.cursor.x)) {
+                .eq => self.cursor.page_cell,
+                .lt => self.cursorCellLeft(@intCast(self.cursor.x - cell_idx)),
+                .gt => self.cursorCellRight(@intCast(cell_idx - self.cursor.x)),
+            };
+
+            try self.cursor.page_pin.page.data.appendGrapheme(
+                self.cursor.page_row,
+                reloaded_cell,
+                cp,
+            );
+        },
+    };
+}
+
 /// Set the selection to the given selection. If this is a tracked selection
 /// then the screen will take overnship of the selection. If this is untracked
 /// then the screen will convert it to tracked internally. This will automatically

src/terminal/Terminal.zig

@@ -351,11 +351,7 @@ pub fn print(self: *Terminal, c: u21) !void {
             }
 
             log.debug("c={x} grapheme attach to left={}", .{ c, prev.left });
-            try self.screen.cursor.page_pin.page.data.appendGrapheme(
-                self.screen.cursor.page_row,
-                prev.cell,
-                c,
-            );
+            try self.screen.appendGrapheme(prev.cell, c);
             return;
         }
     }
@@ -408,11 +404,7 @@ pub fn print(self: *Terminal, c: u21) !void {
             if (!emoji) return;
         }
 
-        try self.screen.cursor.page_pin.page.data.appendGrapheme(
-            self.screen.cursor.page_row,
-            prev,
-            c,
-        );
+        try self.screen.appendGrapheme(prev, c);
         return;
     }
 
@@ -2299,6 +2291,17 @@ test "Terminal: input unique style per cell" {
     }
 }
 
+test "Terminal: input glitch text" {
+    const glitch = @embedFile("res/glitch.txt");
+    const alloc = testing.allocator;
+    var t = try init(alloc, .{ .cols = 30, .rows = 30 });
+    defer t.deinit(alloc);
+
+    for (0..100) |_| {
+        try t.printString(glitch);
+    }
+}
+
 test "Terminal: zero-width character at start" {
     var t = try init(testing.allocator, .{ .cols = 80, .rows = 80 });
     defer t.deinit(testing.allocator);

src/terminal/page.zig

@@ -373,7 +373,7 @@ pub const Page = struct {
     }
 
     /// Append a codepoint to the given cell as a grapheme.
-    pub fn appendGrapheme(self: *Page, row: *Row, cell: *Cell, cp: u21) !void {
+    pub fn appendGrapheme(self: *Page, row: *Row, cell: *Cell, cp: u21) Allocator.Error!void {
         if (comptime std.debug.runtime_safety) assert(cell.hasText());
 
         const cell_offset = getOffset(Cell, self.memory, cell);

src/terminal/res/glitch.txt

@@ -0,0 +1 @@
+Ḡ̴͎͍̜͎͔͕̩̗͕͖̟̜͑̊̌̇̑͒͋͑̄̈́͐̈́́̽͌͂̎̀̔͋̓́̅̌̇͘̕͜͝͝h̶̡̞̫͉̳̬̜̱̥͕͑̾͛̒̆̒̉̒̑͂̄͘ͅǫ̷̨̥͔͔͖̭͚͙̯̟̭̘͇̫̰͚̺̳̙̳̟͚̫̱̹̱͒̂̑͒͜͠ͅş̴̖̰̜̱̹͙̅͒̀̏͆̐̋͂̓͋̃̈̔̂̈͛̐̿̔́̔̄͑̇͑̋̈́͌͋̾̃̽̈́̕͘̚͘͘͘͠͠t̵̢̜̱̦͇͉̬̮̼͖̳̗̥̝̬͇͕̥̜͕̳̱̥̮͉̮̩̘̰̪̤͉͎̲͈͍̳̟̠͈̝̫͋̊̀͐̍̅̀̄̃̈́̔̇̈́̄̃̽̂̌̅̄̋͒̃̈́̍̀̍̇̽̐͊̾̆̅̈̿̓͒̄̾͌̚͝͝͝͝͝t̴̥̼̳̗̬̬͔͎̯͉͇̮̰͖͇̝͔̳̳̗̰͇͎͉̬͇̝̺̯͎͖͔̍͆͒̊̒̔̊̈́̿̊̅͂̐͋̿͂̈̒̄͜͠͠ÿ̴̢̗̜̥͇͖̰͎̝̹̗̪̙̞̣̳͎̯̹͚̲̝̗̳̳̗̖͎̗̬͈͙̝̟͍̥̤͖͇̰͈̺͛̒̂͌̌̏̈̾̓̈́̿͐̂̓̔̓̂̈́͑͛͊͋̔̿̊͑͌̊̏͘͘̕͘͠͝