river/river/view_stack.zig
2020-06-02 17:02:03 +02:00

408 lines
14 KiB
Zig

// This file is part of river, a dynamic tiling wayland compositor.
//
// Copyright 2020 Isaac Freund
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
const View = @import("View.zig");
/// A specialized doubly-linked stack that allows for filtered iteration
/// over the nodes. T must be View or *View.
pub fn ViewStack(comptime T: type) type {
if (!(T == View or T == *View)) {
@compileError("ViewStack: T must be View or *View");
}
return struct {
const Self = @This();
pub const Node = struct {
/// Previous/next nodes in the stack
prev: ?*Node,
next: ?*Node,
/// The view stored in this node
view: T,
};
/// Top/bottom nodes in the stack
first: ?*Node,
last: ?*Node,
/// Initialize an undefined stack
pub fn init(self: *Self) void {
self.first = null;
self.last = null;
}
/// Add a node to the top of the stack.
pub fn push(self: *Self, new_node: *Node) void {
// Set the prev/next pointers of the new node
new_node.prev = null;
new_node.next = self.first;
if (self.first) |first| {
// If the list is not empty, set the prev pointer of the current
// first node to the new node.
first.prev = new_node;
} else {
// If the list is empty set the last pointer to the new node.
self.last = new_node;
}
// Set the first pointer to the new node
self.first = new_node;
}
/// Remove a node from the view stack. This removes it from the stack of
/// all views as well as the stack of visible ones.
pub fn remove(self: *Self, target_node: *Node) void {
// Set the previous node/list head to the next pointer
if (target_node.prev) |prev_node| {
prev_node.next = target_node.next;
} else {
self.first = target_node.next;
}
// Set the next node/list tail to the previous pointer
if (target_node.next) |next_node| {
next_node.prev = target_node.prev;
} else {
self.last = target_node.prev;
}
}
const Iterator = struct {
it: ?*Node,
tags: u32,
reverse: bool,
pending: bool,
/// Returns the next node in iteration order, or null if done.
/// This function is horribly ugly, but it's well tested below.
pub fn next(self: *Iterator) ?*Node {
while (self.it) |node| : (self.it = if (self.reverse) node.prev else node.next) {
if (if (self.pending)
if (node.view.pending_tags) |pending_tags|
self.tags & pending_tags != 0
else
self.tags & node.view.current_tags != 0
else
self.tags & node.view.current_tags != 0) {
self.it = if (self.reverse) node.prev else node.next;
return node;
}
}
return null;
}
};
/// Returns an iterator starting at the passed node and filtered by
/// checking the passed tags against the current tags of each view.
pub fn iterator(start: ?*Node, tags: u32) Iterator {
return Iterator{
.it = start,
.tags = tags,
.reverse = false,
.pending = false,
};
}
/// Returns a reverse iterator starting at the passed node and filtered by
/// checking the passed tags against the current tags of each view.
pub fn reverseIterator(start: ?*Node, tags: u32) Iterator {
return Iterator{
.it = start,
.tags = tags,
.reverse = true,
.pending = false,
};
}
/// Returns an iterator starting at the passed node and filtered by
/// checking the passed tags against the pending tags of each view.
/// If a view has no pending tags, the current tags are used.
pub fn pendingIterator(start: ?*Node, tags: u32) Iterator {
return Iterator{
.it = start,
.tags = tags,
.reverse = false,
.pending = true,
};
}
};
}
test "push/remove (*View)" {
const testing = @import("std").testing;
const allocator = testing.allocator;
var views: ViewStack(*View) = undefined;
views.init();
const one = try allocator.create(ViewStack(*View).Node);
defer allocator.destroy(one);
const two = try allocator.create(ViewStack(*View).Node);
defer allocator.destroy(two);
const three = try allocator.create(ViewStack(*View).Node);
defer allocator.destroy(three);
const four = try allocator.create(ViewStack(*View).Node);
defer allocator.destroy(four);
const five = try allocator.create(ViewStack(*View).Node);
defer allocator.destroy(five);
views.push(three); // {3}
views.push(one); // {1, 3}
views.push(four); // {4, 1, 3}
views.push(five); // {5, 4, 1, 3}
views.push(two); // {2, 5, 4, 1, 3}
// Simple insertion
{
var it = views.first;
testing.expect(it == two);
it = it.?.next;
testing.expect(it == five);
it = it.?.next;
testing.expect(it == four);
it = it.?.next;
testing.expect(it == one);
it = it.?.next;
testing.expect(it == three);
it = it.?.next;
testing.expect(it == null);
testing.expect(views.first == two);
testing.expect(views.last == three);
}
// Removal of first
views.remove(two);
{
var it = views.first;
testing.expect(it == five);
it = it.?.next;
testing.expect(it == four);
it = it.?.next;
testing.expect(it == one);
it = it.?.next;
testing.expect(it == three);
it = it.?.next;
testing.expect(it == null);
testing.expect(views.first == five);
testing.expect(views.last == three);
}
// Removal of last
views.remove(three);
{
var it = views.first;
testing.expect(it == five);
it = it.?.next;
testing.expect(it == four);
it = it.?.next;
testing.expect(it == one);
it = it.?.next;
testing.expect(it == null);
testing.expect(views.first == five);
testing.expect(views.last == one);
}
// Remove from middle
views.remove(four);
{
var it = views.first;
testing.expect(it == five);
it = it.?.next;
testing.expect(it == one);
it = it.?.next;
testing.expect(it == null);
testing.expect(views.first == five);
testing.expect(views.last == one);
}
// Reinsertion
views.push(two);
views.push(three);
views.push(four);
{
var it = views.first;
testing.expect(it == four);
it = it.?.next;
testing.expect(it == three);
it = it.?.next;
testing.expect(it == two);
it = it.?.next;
testing.expect(it == five);
it = it.?.next;
testing.expect(it == one);
it = it.?.next;
testing.expect(it == null);
testing.expect(views.first == four);
testing.expect(views.last == one);
}
// Clear
views.remove(four);
views.remove(two);
views.remove(three);
views.remove(one);
views.remove(five);
testing.expect(views.first == null);
testing.expect(views.last == null);
}
test "iteration (View)" {
const c = @import("c.zig");
const std = @import("std");
const testing = std.testing;
const allocator = testing.allocator;
var views: ViewStack(View) = undefined;
views.init();
const one_a_pb = try allocator.create(ViewStack(View).Node);
defer allocator.destroy(one_a_pb);
one_a_pb.view.current_tags = 1 << 0;
one_a_pb.view.pending_tags = 1 << 1;
const two_a = try allocator.create(ViewStack(View).Node);
defer allocator.destroy(two_a);
two_a.view.current_tags = 1 << 0;
two_a.view.pending_tags = null;
const three_b_pa = try allocator.create(ViewStack(View).Node);
defer allocator.destroy(three_b_pa);
three_b_pa.view.current_tags = 1 << 1;
three_b_pa.view.pending_tags = 1 << 0;
const four_b = try allocator.create(ViewStack(View).Node);
defer allocator.destroy(four_b);
four_b.view.current_tags = 1 << 1;
four_b.view.pending_tags = null;
const five_b = try allocator.create(ViewStack(View).Node);
defer allocator.destroy(five_b);
five_b.view.current_tags = 1 << 1;
five_b.view.pending_tags = null;
views.push(three_b_pa); // {3}
views.push(one_a_pb); // {1, 3}
views.push(four_b); // {4, 1, 3}
views.push(five_b); // {5, 4, 1, 3}
views.push(two_a); // {2, 5, 4, 1, 3}
// Iteration over all tags
{
var it = ViewStack(View).iterator(views.first, std.math.maxInt(u32));
testing.expect((if (it.next()) |node| &node.view else null) == &two_a.view);
testing.expect((if (it.next()) |node| &node.view else null) == &five_b.view);
testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
testing.expect((if (it.next()) |node| &node.view else null) == &one_a_pb.view);
testing.expect((if (it.next()) |node| &node.view else null) == &three_b_pa.view);
testing.expect(it.next() == null);
}
// Iteration over 'a' tags
{
var it = ViewStack(View).iterator(views.first, 1 << 0);
testing.expect((if (it.next()) |node| &node.view else null) == &two_a.view);
testing.expect((if (it.next()) |node| &node.view else null) == &one_a_pb.view);
testing.expect(it.next() == null);
}
// Iteration over 'b' tags
{
var it = ViewStack(View).iterator(views.first, 1 << 1);
testing.expect((if (it.next()) |node| &node.view else null) == &five_b.view);
testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
testing.expect((if (it.next()) |node| &node.view else null) == &three_b_pa.view);
testing.expect(it.next() == null);
}
// Iteration over tags that aren't present
{
var it = ViewStack(View).iterator(views.first, 1 << 2);
testing.expect(it.next() == null);
}
// Reverse iteration over all tags
{
var it = ViewStack(View).reverseIterator(views.last, std.math.maxInt(u32));
testing.expect((if (it.next()) |node| &node.view else null) == &three_b_pa.view);
testing.expect((if (it.next()) |node| &node.view else null) == &one_a_pb.view);
testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
testing.expect((if (it.next()) |node| &node.view else null) == &five_b.view);
testing.expect((if (it.next()) |node| &node.view else null) == &two_a.view);
testing.expect(it.next() == null);
}
// Reverse iteration over 'a' tags
{
var it = ViewStack(View).reverseIterator(views.last, 1 << 0);
testing.expect((if (it.next()) |node| &node.view else null) == &one_a_pb.view);
testing.expect((if (it.next()) |node| &node.view else null) == &two_a.view);
testing.expect(it.next() == null);
}
// Reverse iteration over 'b' tags
{
var it = ViewStack(View).reverseIterator(views.last, 1 << 1);
testing.expect((if (it.next()) |node| &node.view else null) == &three_b_pa.view);
testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
testing.expect((if (it.next()) |node| &node.view else null) == &five_b.view);
testing.expect(it.next() == null);
}
// Reverse iteration over tags that aren't present
{
var it = ViewStack(View).reverseIterator(views.first, 1 << 2);
testing.expect(it.next() == null);
}
// Iteration over (pending) 'a' tags
{
var it = ViewStack(View).pendingIterator(views.first, 1 << 0);
testing.expect((if (it.next()) |node| &node.view else null) == &two_a.view);
testing.expect((if (it.next()) |node| &node.view else null) == &three_b_pa.view);
testing.expect(it.next() == null);
}
// Iteration over (pending) 'b' tags
{
var it = ViewStack(View).pendingIterator(views.first, 1 << 1);
testing.expect((if (it.next()) |node| &node.view else null) == &five_b.view);
testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
testing.expect((if (it.next()) |node| &node.view else null) == &one_a_pb.view);
testing.expect(it.next() == null);
}
// Iteration over (pending) tags that aren't present
{
var it = ViewStack(View).pendingIterator(views.first, 1 << 2);
testing.expect(it.next() == null);
}
}