terminal/new: fix allocation

src/terminal/new/PageList.zig

@@ -210,22 +210,20 @@ fn ensureRows(self: *PageList, row: RowOffset, n: usize) !void {
         self.pages.insertAfter(page, next_page);
         page = next_page;
 
-        // we expect the pages at this point to be full capacity. we
-        // shrink them if we have to since they've never been used.
-        assert(page.data.size.rows == page.data.capacity.rows);
-
         // If we have enough space, use it.
-        if (n_rem <= page.data.size.rows) {
+        if (n_rem <= page.data.capacity.rows) {
             page.data.size.rows = @intCast(n_rem);
             return;
         }
 
+        // created pages are always empty so fill it with blanks
+        page.data.size.rows = page.data.capacity.rows;
+
         // Continue
         n_rem -= page.data.size.rows;
     }
 }
 
-// TODO: test, refine
 pub fn grow(self: *PageList) !*List.Node {
     const next_page = try self.createPage();
     // we don't errdefer this because we've added it to the linked
@@ -246,6 +244,7 @@ fn createPage(self: *PageList) !*List.Node {
             .styles = page_default_styles,
         }),
     };
+    page.data.size.rows = 0;
 
     return page;
 }

src/terminal/new/PagePool.zig

@@ -0,0 +1,8 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const assert = std.debug.assert;
+
+test {
+    const testing = std.testing;
+    try testing.expect(false);
+}

src/terminal/new/Screen.zig

@@ -136,6 +136,8 @@ pub fn cursorDownScroll(self: *Screen) !void {
     // No space, we need to allocate a new page and move the cursor to it.
 
     const new_page = try self.pages.grow();
+    assert(new_page.data.size.rows == 0);
+    new_page.data.size.rows = 1;
     const page_offset: PageList.RowOffset = .{
         .page = new_page,
         .row_offset = 0,

src/terminal/new/main.zig

@@ -2,6 +2,7 @@ const builtin = @import("builtin");
 
 const page = @import("page.zig");
 pub const PageList = @import("PageList.zig");
+pub const PagePool = @import("PagePool.zig");
 pub const Terminal = @import("Terminal.zig");
 pub const Page = page.Page;
 
@@ -12,7 +13,6 @@ test {
     _ = @import("bitmap_allocator.zig");
     _ = @import("hash_map.zig");
     _ = @import("page.zig");
-    _ = @import("PageList.zig");
     _ = @import("Screen.zig");
     _ = @import("point.zig");
     _ = @import("size.zig");

src/terminal/new/page.zig

@@ -95,8 +95,8 @@ pub const Page = struct {
     /// requirements. This is enough to support a very large number of cells.
     /// The standard capacity is chosen as the fast-path for allocation.
     pub const std_capacity: Capacity = .{
-        .cols = 250,
-        .rows = 250,
+        .cols = 120,
+        .rows = 520,
         .styles = 128,
         .grapheme_bytes = 1024,
     };