perf(eval): reduce memory usage

1 files changed, 23 insertions, 11 deletions

diff --git a/src/eval/Root.zig b/src/eval/Root.zig
index fc59c1d..d4ccf30 100644
--- a/src/eval/Root.zig
+++ b/src/eval/Root.zig
@@ -3,21 +3,23 @@ const Allocator = std.mem.Allocator;
 const Arena = std.heap.ArenaAllocator;
 const HTML = @import("html/Element.zig");
 const Element = @import("Element.zig");
+const Node = Element.Node;
 
 const Self = @This();
 
-content: std.ArrayList(Element),
+content: std.DoublyLinkedList = .{},
 arena: Arena,
+node: Node = .{
+    .ptr = undefined,
+    .vtable = .{ .element = fromNode },
+},
 
 pub fn init(parent: Allocator) !*Self {
-    var s = Self{
-        .content = undefined,
-        .arena = .init(parent),
-    };
+    var s = Self{ .arena = .init(parent) };
     var alloc = s.arena.allocator();
-    s.content = try .initCapacity(alloc, 2);
     const v = try alloc.create(Self);
     v.* = s;
+    v.node.ptr = v;
     return v;
 }
 
@@ -29,22 +31,32 @@ pub fn allocator(self: *Self) Allocator {
     return self.arena.allocator();
 }
 
-pub fn append(self: *Self, el: Element) !void {
-    try self.content.append(self.allocator(), el);
+pub fn append(self: *Self, el: Element) void {
+    self.content.append(&el.node().node);
 }
 
 pub fn element(self: *Self) Element {
-    return .{ .vtable = .{ .html = html }, .ptr = self };
+    return .{ .vtable = .{ .html = html, .node = getNode }, .ptr = self };
 }
 
 pub fn renderHTML(self: *Self, alloc: Allocator) HTML.Error![]const u8 {
     return try self.element().renderHTML(alloc);
 }
 
+fn getNode(context: *anyopaque) *Node {
+    const self: *Self = @ptrCast(@alignCast(context));
+    return &self.node;
+}
+
+fn fromNode(context: *anyopaque) Element {
+    const self: *Self = @ptrCast(@alignCast(context));
+    return self.element();
+}
+
 fn html(context: *anyopaque, alloc: Allocator) HTML.Error!HTML {
     const self: *Self = @ptrCast(@alignCast(context));
     const el = try HTML.Root.init(alloc);
-    if (self.content.items.len == 0) return el.element();
-    for (self.content.items) |it| el.append(try it.html(el.allocator()));
+    var v = self.content.first;
+    while (v) |it| : (v = it.next) el.append(try Node.from(it).element().html(el.allocator()));
     return el.element();
 }