486 lines
16 KiB
Zig
486 lines
16 KiB
Zig
// This file is part of river, a dynamic tiling wayland compositor.
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//
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// Copyright 2020 The River Developers
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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const View = @import("View.zig");
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pub const AttachMode = enum {
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top,
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bottom,
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};
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/// A specialized doubly-linked stack that allows for filtered iteration
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/// over the nodes. T must be View or *View.
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pub fn ViewStack(comptime T: type) type {
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if (!(T == View or T == *View)) {
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@compileError("ViewStack: T must be View or *View");
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}
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return struct {
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const Self = @This();
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pub const Node = struct {
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/// Previous/next nodes in the stack
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prev: ?*Node,
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next: ?*Node,
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/// The view stored in this node
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view: T,
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};
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/// Top/bottom nodes in the stack
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first: ?*Node = null,
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last: ?*Node = null,
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/// Add a node to the top of the stack.
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pub fn push(self: *Self, new_node: *Node) void {
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// Set the prev/next pointers of the new node
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new_node.prev = null;
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new_node.next = self.first;
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if (self.first) |first| {
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// If the list is not empty, set the prev pointer of the current
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// first node to the new node.
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first.prev = new_node;
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} else {
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// If the list is empty set the last pointer to the new node.
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self.last = new_node;
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}
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// Set the first pointer to the new node
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self.first = new_node;
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}
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/// Add a node to the bottom of the stack.
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pub fn append(self: *Self, new_node: *Node) void {
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// Set the prev/next pointers of the new node
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new_node.prev = self.last;
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new_node.next = null;
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if (self.last) |last| {
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// If the list is not empty, set the next pointer of the current
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// first node to the new node.
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last.next = new_node;
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} else {
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// If the list is empty set the first pointer to the new node.
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self.first = new_node;
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}
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// Set the last pointer to the new node
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self.last = new_node;
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}
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/// Attach a node into the viewstack based on the attach mode
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pub fn attach(self: *Self, new_node: *Node, mode: AttachMode) void {
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switch (mode) {
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.top => self.push(new_node),
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.bottom => self.append(new_node),
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}
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}
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/// Remove a node from the view stack. This removes it from the stack of
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/// all views as well as the stack of visible ones.
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pub fn remove(self: *Self, target_node: *Node) void {
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// Set the previous node/list head to the next pointer
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if (target_node.prev) |prev_node| {
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prev_node.next = target_node.next;
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} else {
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self.first = target_node.next;
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}
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// Set the next node/list tail to the previous pointer
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if (target_node.next) |next_node| {
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next_node.prev = target_node.prev;
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} else {
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self.last = target_node.prev;
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}
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}
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/// Swap the nodes a and b.
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/// pointers to Node.T will point to the same data as before
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pub fn swap(self: *Self, a: *Node, b: *Node) void {
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// Set self.first and self.last
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const first = self.first;
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const last = self.last;
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if (a == first) {
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self.first = b;
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} else if (a == last) {
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self.last = b;
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}
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if (b == first) {
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self.first = a;
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} else if (b == last) {
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self.last = a;
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}
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// This is so complicated to make sure everything works when a and b are neighbors
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const a_next = if (b.next == a) b else b.next;
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const a_prev = if (b.prev == a) b else b.prev;
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const b_next = if (a.next == b) a else a.next;
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const b_prev = if (a.prev == b) a else a.prev;
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a.next = a_next;
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a.prev = a_prev;
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b.next = b_next;
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b.prev = b_prev;
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// Update all neighbors
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if (a.next) |next| {
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next.prev = a;
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}
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if (a.prev) |prev| {
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prev.next = a;
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}
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if (b.next) |next| {
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next.prev = b;
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}
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if (b.prev) |prev| {
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prev.next = b;
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}
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}
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const Direction = enum {
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forward,
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reverse,
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};
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fn Iter(comptime Context: type) type {
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return struct {
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it: ?*Node,
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dir: Direction,
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context: Context,
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filter: fn (*View, Context) bool,
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/// Returns the next node in iteration order which passes the
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/// filter, or null if done.
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pub fn next(self: *@This()) ?*View {
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return while (self.it) |node| : (self.it = if (self.dir == .forward) node.next else node.prev) {
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const view = if (T == View) &node.view else node.view;
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if (self.filter(view, self.context)) {
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self.it = if (self.dir == .forward) node.next else node.prev;
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break view;
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}
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} else null;
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}
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};
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}
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/// Return a filtered iterator over the stack given a start node,
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/// iteration direction, and filter function. Views for which the
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/// filter function returns false will be skipped.
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pub fn iter(
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start: ?*Node,
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dir: Direction,
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context: anytype,
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filter: fn (*View, @TypeOf(context)) bool,
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) Iter(@TypeOf(context)) {
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return .{ .it = start, .dir = dir, .context = context, .filter = filter };
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}
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};
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}
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test "push/remove (*View)" {
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const testing = @import("std").testing;
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const allocator = testing.allocator;
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var views = ViewStack(*View){};
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const one = try allocator.create(ViewStack(*View).Node);
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defer allocator.destroy(one);
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const two = try allocator.create(ViewStack(*View).Node);
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defer allocator.destroy(two);
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const three = try allocator.create(ViewStack(*View).Node);
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defer allocator.destroy(three);
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const four = try allocator.create(ViewStack(*View).Node);
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defer allocator.destroy(four);
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const five = try allocator.create(ViewStack(*View).Node);
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defer allocator.destroy(five);
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views.push(three); // {3}
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views.push(one); // {1, 3}
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views.push(four); // {4, 1, 3}
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views.push(five); // {5, 4, 1, 3}
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views.push(two); // {2, 5, 4, 1, 3}
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// Simple insertion
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{
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var it = views.first;
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try testing.expect(it == two);
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it = it.?.next;
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try testing.expect(it == five);
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it = it.?.next;
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try testing.expect(it == four);
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it = it.?.next;
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try testing.expect(it == one);
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it = it.?.next;
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try testing.expect(it == three);
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it = it.?.next;
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try testing.expect(it == null);
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try testing.expect(views.first == two);
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try testing.expect(views.last == three);
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}
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// Removal of first
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views.remove(two);
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{
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var it = views.first;
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try testing.expect(it == five);
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it = it.?.next;
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try testing.expect(it == four);
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it = it.?.next;
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try testing.expect(it == one);
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it = it.?.next;
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try testing.expect(it == three);
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it = it.?.next;
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try testing.expect(it == null);
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try testing.expect(views.first == five);
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try testing.expect(views.last == three);
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}
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// Removal of last
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views.remove(three);
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{
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var it = views.first;
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try testing.expect(it == five);
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it = it.?.next;
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try testing.expect(it == four);
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it = it.?.next;
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try testing.expect(it == one);
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it = it.?.next;
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try testing.expect(it == null);
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try testing.expect(views.first == five);
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try testing.expect(views.last == one);
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}
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// Remove from middle
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views.remove(four);
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{
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var it = views.first;
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try testing.expect(it == five);
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it = it.?.next;
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try testing.expect(it == one);
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it = it.?.next;
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try testing.expect(it == null);
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try testing.expect(views.first == five);
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try testing.expect(views.last == one);
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}
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// Reinsertion
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views.push(two);
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views.push(three);
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views.push(four);
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{
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var it = views.first;
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try testing.expect(it == four);
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it = it.?.next;
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try testing.expect(it == three);
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it = it.?.next;
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try testing.expect(it == two);
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it = it.?.next;
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try testing.expect(it == five);
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it = it.?.next;
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try testing.expect(it == one);
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it = it.?.next;
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try testing.expect(it == null);
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try testing.expect(views.first == four);
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try testing.expect(views.last == one);
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}
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// Clear
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views.remove(four);
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views.remove(two);
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views.remove(three);
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views.remove(one);
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views.remove(five);
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try testing.expect(views.first == null);
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try testing.expect(views.last == null);
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}
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test "iteration (View)" {
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const std = @import("std");
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const testing = std.testing;
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const allocator = testing.allocator;
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const filters = struct {
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fn all(_: *View, _: void) bool {
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return true;
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}
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fn none(_: *View, _: void) bool {
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return false;
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}
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fn current(view: *View, filter_tags: u32) bool {
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return view.current.tags & filter_tags != 0;
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}
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};
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var views = ViewStack(View){};
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const one_a_pb = try allocator.create(ViewStack(View).Node);
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defer allocator.destroy(one_a_pb);
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one_a_pb.view.current.tags = 1 << 0;
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one_a_pb.view.pending.tags = 1 << 1;
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const two_a = try allocator.create(ViewStack(View).Node);
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defer allocator.destroy(two_a);
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two_a.view.current.tags = 1 << 0;
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two_a.view.pending.tags = 1 << 0;
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const three_b_pa = try allocator.create(ViewStack(View).Node);
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defer allocator.destroy(three_b_pa);
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three_b_pa.view.current.tags = 1 << 1;
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three_b_pa.view.pending.tags = 1 << 0;
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const four_b = try allocator.create(ViewStack(View).Node);
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defer allocator.destroy(four_b);
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four_b.view.current.tags = 1 << 1;
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four_b.view.pending.tags = 1 << 1;
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const five_b = try allocator.create(ViewStack(View).Node);
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defer allocator.destroy(five_b);
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five_b.view.current.tags = 1 << 1;
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five_b.view.pending.tags = 1 << 1;
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views.push(three_b_pa); // {3}
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views.push(one_a_pb); // {1, 3}
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views.push(four_b); // {4, 1, 3}
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views.push(five_b); // {5, 4, 1, 3}
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views.push(two_a); // {2, 5, 4, 1, 3}
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// Iteration over all views
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{
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var it = ViewStack(View).iter(views.first, .forward, {}, filters.all);
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try testing.expect(it.next() == &two_a.view);
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try testing.expect(it.next() == &five_b.view);
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try testing.expect(it.next() == &four_b.view);
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try testing.expect(it.next() == &one_a_pb.view);
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try testing.expect(it.next() == &three_b_pa.view);
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try testing.expect(it.next() == null);
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}
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// Iteration over no views
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{
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var it = ViewStack(View).iter(views.first, .forward, {}, filters.none);
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try testing.expect(it.next() == null);
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}
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// Iteration over 'a' tags
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{
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var it = ViewStack(View).iter(views.first, .forward, @as(u32, 1 << 0), filters.current);
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try testing.expect(it.next() == &two_a.view);
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try testing.expect(it.next() == &one_a_pb.view);
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try testing.expect(it.next() == null);
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}
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// Iteration over 'b' tags
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{
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var it = ViewStack(View).iter(views.first, .forward, @as(u32, 1 << 1), filters.current);
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try testing.expect(it.next() == &five_b.view);
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try testing.expect(it.next() == &four_b.view);
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try testing.expect(it.next() == &three_b_pa.view);
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try testing.expect(it.next() == null);
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}
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// Reverse iteration over all views
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{
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var it = ViewStack(View).iter(views.last, .reverse, {}, filters.all);
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try testing.expect(it.next() == &three_b_pa.view);
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try testing.expect(it.next() == &one_a_pb.view);
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try testing.expect(it.next() == &four_b.view);
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try testing.expect(it.next() == &five_b.view);
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try testing.expect(it.next() == &two_a.view);
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try testing.expect(it.next() == null);
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}
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// Reverse iteration over no views
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{
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var it = ViewStack(View).iter(views.last, .reverse, {}, filters.none);
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try testing.expect(it.next() == null);
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}
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// Reverse iteration over 'a' tags
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{
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var it = ViewStack(View).iter(views.last, .reverse, @as(u32, 1 << 0), filters.current);
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try testing.expect(it.next() == &one_a_pb.view);
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try testing.expect(it.next() == &two_a.view);
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try testing.expect(it.next() == null);
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}
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// Reverse iteration over 'b' tags
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{
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var it = ViewStack(View).iter(views.last, .reverse, @as(u32, 1 << 1), filters.current);
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try testing.expect(it.next() == &three_b_pa.view);
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try testing.expect(it.next() == &four_b.view);
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try testing.expect(it.next() == &five_b.view);
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try testing.expect(it.next() == null);
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}
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// Swap, then iterate
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{
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var view_a = views.first orelse unreachable;
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var view_b = view_a.next orelse unreachable;
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ViewStack(View).swap(&views, view_a, view_b); // {2, 5, 4, 1, 3} -> {5, 2, 4, 1, 3}
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view_a = views.last orelse unreachable;
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view_b = view_a.prev orelse unreachable;
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ViewStack(View).swap(&views, view_a, view_b); // {5, 2, 4, 1, 3} -> {5, 2, 4, 3, 1}
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view_a = views.last orelse unreachable;
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view_b = views.first orelse unreachable;
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ViewStack(View).swap(&views, view_a, view_b); // {5, 2, 4, 3, 1} -> {1, 2, 4, 3, 5}
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view_a = views.first orelse unreachable;
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view_b = views.last orelse unreachable;
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ViewStack(View).swap(&views, view_a, view_b); // {1, 2, 4, 3, 5} -> {5, 2, 4, 3, 1}
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view_a = views.first orelse unreachable;
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view_a = view_a.next orelse unreachable;
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view_b = view_a.next orelse unreachable;
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view_b = view_b.next orelse unreachable;
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ViewStack(View).swap(&views, view_a, view_b); // {5, 2, 4, 3, 1} -> {5, 3, 4, 2, 1}
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var it = ViewStack(View).iter(views.first, .forward, {}, filters.all);
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try testing.expect(it.next() == &five_b.view);
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try testing.expect(it.next() == &three_b_pa.view);
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try testing.expect(it.next() == &four_b.view);
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try testing.expect(it.next() == &two_a.view);
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try testing.expect(it.next() == &one_a_pb.view);
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try testing.expect(it.next() == null);
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it = ViewStack(View).iter(views.last, .reverse, {}, filters.all);
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try testing.expect(it.next() == &one_a_pb.view);
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try testing.expect(it.next() == &two_a.view);
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try testing.expect(it.next() == &four_b.view);
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try testing.expect(it.next() == &three_b_pa.view);
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try testing.expect(it.next() == &five_b.view);
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try testing.expect(it.next() == null);
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}
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}
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