terminal/new: scrollactive

src/bench/stream-new.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+#
+# This is a trivial helper script to help run the stream benchmark.
+# You probably want to tweak this script depending on what you're
+# trying to measure.
+
+# Options:
+# - "ascii", uniform random ASCII bytes
+# - "utf8", uniform random unicode characters, encoded as utf8
+# - "rand", pure random data, will contain many invalid code sequences.
+DATA="ascii"
+SIZE="25000000"
+
+# Uncomment to test with an active terminal state.
+# ARGS=" --terminal"
+
+# Generate the benchmark input ahead of time so it's not included in the time.
+./zig-out/bin/bench-stream --mode=gen-$DATA | head -c $SIZE > /tmp/ghostty_bench_data
+
+# Uncomment to instead use the contents of `stream.txt` as input. (Ignores SIZE)
+# echo $(cat ./stream.txt) > /tmp/ghostty_bench_data
+
+hyperfine \
+  --warmup 10 \
+  -n noop \
+  "./zig-out/bin/bench-stream --mode=noop </tmp/ghostty_bench_data" \
+  -n old \
+  "./zig-out/bin/bench-stream --mode=simd --terminal=old </tmp/ghostty_bench_data" \
+  -n new \
+  "./zig-out/bin/bench-stream --mode=simd --terminal=new </tmp/ghostty_bench_data"

src/terminal/new/PageList.zig

@@ -117,7 +117,7 @@ pub fn deinit(self: *PageList) void {
 /// Scroll the active area down by n lines. If the n lines go beyond the
 /// end of the screen, this will add new pages as necessary. This does
 /// not move the viewport.
-pub fn scrollDown(self: *PageList, n: usize) !void {
+pub fn scrollActive(self: *PageList, n: usize) !void {
     // Move our active area down as much as possible towards n. The return
     // value is the amount of rows we were short in any existing page, and
     // we must expand at least that much. This does not include the size
@@ -297,6 +297,10 @@ pub const RowOffset = struct {
     page: *List.Node,
     row_offset: usize = 0,
 
+    pub fn eql(self: RowOffset, other: RowOffset) bool {
+        return self.page == other.page and self.row_offset == other.row_offset;
+    }
+
     pub fn rowAndCell(self: RowOffset, x: usize) struct {
         row: *pagepkg.Row,
         cell: *pagepkg.Cell,
@@ -327,7 +331,7 @@ pub const RowOffset = struct {
         },
     } {
         // Index fits within this page
-        var rows = self.page.data.size.rows - (self.row_offset + 1);
+        const rows = self.page.data.size.rows - (self.row_offset + 1);
         if (n <= rows) return .{ .offset = .{
             .page = self.page,
             .row_offset = n + self.row_offset,
@@ -335,20 +339,18 @@ pub const RowOffset = struct {
 
         // Need to traverse page links to find the page
         var page: *List.Node = self.page;
-        var n_left: usize = n;
-        while (n_left >= rows) {
-            n_left -= rows;
+        var n_left: usize = n - rows;
+        while (true) {
             page = page.next orelse return .{ .overflow = .{
                 .end = .{ .page = page, .row_offset = page.data.size.rows - 1 },
                 .remaining = n_left,
             } };
-            rows = page.data.size.rows;
+            if (n_left <= page.data.size.rows) return .{ .offset = .{
+                .page = page,
+                .row_offset = n_left - 1,
+            } };
+            n_left -= page.data.size.rows;
         }
-
-        return .{ .offset = .{
-            .page = page,
-            .row_offset = n_left,
-        } };
     }
 };
 
@@ -378,7 +380,7 @@ test "PageList" {
     try testing.expectEqual(s.active, s.viewport);
 }
 
-test "scrollDown utilizes capacity" {
+test "scrollActive utilizes capacity" {
     const testing = std.testing;
     const alloc = testing.allocator;
 
@@ -391,7 +393,7 @@ test "scrollDown utilizes capacity" {
     try testing.expect(s.active.row_offset == 0);
     try testing.expectEqual(@as(size.CellCountInt, 1), s.active.page.data.size.rows);
 
-    try s.scrollDown(1);
+    try s.scrollActive(1);
 
     // We should not allocate a new page because we have enough capacity
     try testing.expect(s.active.page == s.pages.first);
@@ -400,7 +402,7 @@ test "scrollDown utilizes capacity" {
     try testing.expectEqual(@as(size.CellCountInt, 2), s.active.page.data.size.rows);
 }
 
-test "scrollDown adds new pages" {
+test "scrollActive adds new pages" {
     const testing = std.testing;
     const alloc = testing.allocator;
 
@@ -414,7 +416,7 @@ test "scrollDown adds new pages" {
 
     // The initial active is a single page so scrolling down even one
     // should force the allocation of an entire new page.
-    try s.scrollDown(1);
+    try s.scrollActive(1);
 
     // We should still be on the first page but offset, and we should
     // have a second page created.

src/terminal/new/Screen.zig

@@ -114,6 +114,24 @@ pub fn cursorHorizontalAbsolute(self: *Screen, x: size.CellCountInt) void {
     self.cursor.x = x;
 }
 
+/// Scroll the active area and keep the cursor at the bottom of the screen.
+/// This is a very specialized function but it keeps it fast.
+pub fn cursorDownScroll(self: *Screen) !void {
+    assert(self.cursor.y == self.pages.rows - 1);
+
+    // We move the viewport to the active if we're already there to start.
+    const move_viewport = self.pages.viewport.eql(self.pages.active);
+
+    try self.pages.scrollActive(1);
+    const page_offset = self.pages.active.forward(self.cursor.y).?;
+    const page_rac = page_offset.rowAndCell(self.cursor.x);
+    self.cursor.page_offset = page_offset;
+    self.cursor.page_row = page_rac.row;
+    self.cursor.page_cell = page_rac.cell;
+
+    if (move_viewport) self.pages.viewport = self.pages.active;
+}
+
 /// Dump the screen to a string. The writer given should be buffered;
 /// this function does not attempt to efficiently write and generally writes
 /// one byte at a time.

src/terminal/new/Terminal.zig

@@ -173,9 +173,9 @@ pub fn init(alloc: Allocator, cols: size.CellCountInt, rows: size.CellCountInt)
         .rows = rows,
         .active_screen = .primary,
         // TODO: configurable scrollback
-        .screen = try Screen.init(alloc, rows, cols, 10000),
+        .screen = try Screen.init(alloc, cols, rows, 10000),
         // No scrollback for the alternate screen
-        .secondary_screen = try Screen.init(alloc, rows, cols, 0),
+        .secondary_screen = try Screen.init(alloc, cols, rows, 0),
         .tabstops = try Tabstops.init(alloc, cols, TABSTOP_INTERVAL),
         .scrolling_region = .{
             .top = 0,
@@ -396,8 +396,7 @@ pub fn index(self: *Terminal) !void {
             self.scrolling_region.left == 0 and
             self.scrolling_region.right == self.cols - 1)
         {
-            @panic("TODO: scroll screen");
-            //try self.screen.scroll(.{ .screen = 1 });
+            try self.screen.cursorDownScroll();
         } else {
             @panic("TODO: scroll up");
             //try self.scrollUp(1);
@@ -453,6 +452,22 @@ test "Terminal: input with basic wraparound" {
     }
 }
 
+test "Terminal: input that forces scroll" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 1, 5);
+    defer t.deinit(alloc);
+
+    // Basic grid writing
+    for ("abcdef") |c| try t.print(c);
+    try testing.expectEqual(@as(usize, 4), t.screen.cursor.y);
+    try testing.expectEqual(@as(usize, 0), t.screen.cursor.x);
+    {
+        const str = try t.plainString(alloc);
+        defer alloc.free(str);
+        try testing.expectEqualStrings("b\nc\nd\ne\nf", str);
+    }
+}
+
 test "Terminal: zero-width character at start" {
     var t = try init(testing.allocator, 80, 80);
     defer t.deinit(testing.allocator);
@@ -466,11 +481,11 @@ test "Terminal: zero-width character at start" {
 }
 
 // https://github.com/mitchellh/ghostty/issues/1400
-// test "Terminal: print single very long line" {
-//     var t = try init(testing.allocator, 5, 5);
-//     defer t.deinit(testing.allocator);
-//
-//     // This would crash for issue 1400. So the assertion here is
-//     // that we simply do not crash.
-//     for (0..500) |_| try t.print('x');
-// }
+test "Terminal: print single very long line" {
+    var t = try init(testing.allocator, 5, 5);
+    defer t.deinit(testing.allocator);
+
+    // This would crash for issue 1400. So the assertion here is
+    // that we simply do not crash.
+    for (0..1000) |_| try t.print('x');
+}