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view stack: rework iteration for flexibility

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There is now a single iter() function which accepts a filter and context
allowing users of the api to filter the views in any arbitrary way. This
change allowed for a good amount of code cleanup, and this commit also
ensures that the correct properties are checked in each case, including
the new View.destroying field added in the previous commit. This fixes
at least one crash involving switching focus to a destroying view.
This commit is contained in:
Isaac Freund
2020-08-21 15:08:28 +02:00
parent fa08d85c58
commit db416eb119
9 changed files with 185 additions and 217 deletions
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205
river/view_stack.zig
View File

@ -41,14 +41,8 @@ pub fn ViewStack(comptime T: type) type {
};
/// 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;
}
first: ?*Node = null,
last: ?*Node = null,
/// Add a node to the top of the stack.
pub fn push(self: *Self, new_node: *Node) void {
@ -114,60 +108,42 @@ pub fn ViewStack(comptime T: type) type {
}
}
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)
self.tags & node.view.pending.tags != 0
else
self.tags & node.view.current.tags != 0) {
self.it = if (self.reverse) node.prev else node.next;
return node;
}
}
return null;
}
const Direction = enum {
forward,
reverse,
};
/// 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,
fn Iter(comptime Context: type) type {
return struct {
it: ?*Node,
dir: Direction,
context: Context,
filter: fn (*View, Context) bool,
/// Returns the next node in iteration order which passes the
/// filter, or null if done.
pub fn next(self: *@This()) ?*View {
return while (self.it) |node| : (self.it = if (self.dir == .forward) node.next else node.prev) {
const view = if (T == View) &node.view else node.view;
if (self.filter(view, self.context)) {
self.it = if (self.dir == .forward) node.next else node.prev;
break view;
}
} else null;
}
};
}
/// 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,
};
/// Return a filtered iterator over the stack given a start node,
/// iteration direction, and filter function. Views for which the
/// filter function returns false will be skipped.
pub fn iter(
start: ?*Node,
dir: Direction,
context: var,
filter: fn (*View, @TypeOf(context)) bool,
) Iter(@TypeOf(context)) {
return .{ .it = start, .dir = dir, .context = context, .filter = filter };
}
};
}
@ -177,8 +153,7 @@ test "push/remove (*View)" {
const allocator = testing.allocator;
var views: ViewStack(*View) = undefined;
views.init();
var views = ViewStack(*View){};
const one = try allocator.create(ViewStack(*View).Node);
defer allocator.destroy(one);
@ -309,8 +284,21 @@ test "iteration (View)" {
const allocator = testing.allocator;
var views: ViewStack(View) = undefined;
views.init();
const filters = struct {
fn all(view: *View, context: void) bool {
return true;
}
fn none(view: *View, context: void) bool {
return false;
}
fn current(view: *View, filter_tags: u32) bool {
return view.current.tags & filter_tags != 0;
}
};
var views = ViewStack(View){};
const one_a_pb = try allocator.create(ViewStack(View).Node);
defer allocator.destroy(one_a_pb);
@ -343,94 +331,71 @@ test "iteration (View)" {
views.push(five_b); // {5, 4, 1, 3}
views.push(two_a); // {2, 5, 4, 1, 3}
// Iteration over all tags
// Iteration over all views
{
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);
var it = ViewStack(View).iter(views.first, .forward, {}, filters.all);
testing.expect(it.next() == &two_a.view);
testing.expect(it.next() == &five_b.view);
testing.expect(it.next() == &four_b.view);
testing.expect(it.next() == &one_a_pb.view);
testing.expect(it.next() == &three_b_pa.view);
testing.expect(it.next() == null);
}
// Iteration over no views
{
var it = ViewStack(View).iter(views.first, .forward, {}, filters.none);
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);
var it = ViewStack(View).iter(views.first, .forward, @as(u32, 1 << 0), filters.current);
testing.expect(it.next() == &two_a.view);
testing.expect(it.next() == &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);
var it = ViewStack(View).iter(views.first, .forward, @as(u32, 1 << 1), filters.current);
testing.expect(it.next() == &five_b.view);
testing.expect(it.next() == &four_b.view);
testing.expect(it.next() == &three_b_pa.view);
testing.expect(it.next() == null);
}
// Iteration over tags that aren't present
// Reverse iteration over all views
{
var it = ViewStack(View).iterator(views.first, 1 << 2);
var it = ViewStack(View).iter(views.last, .reverse, {}, filters.all);
testing.expect(it.next() == &three_b_pa.view);
testing.expect(it.next() == &one_a_pb.view);
testing.expect(it.next() == &four_b.view);
testing.expect(it.next() == &five_b.view);
testing.expect(it.next() == &two_a.view);
testing.expect(it.next() == null);
}
// Reverse iteration over all tags
// Reverse iteration over no views
{
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);
var it = ViewStack(View).iter(views.last, .reverse, {}, filters.none);
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);
var it = ViewStack(View).iter(views.last, .reverse, @as(u32, 1 << 0), filters.current);
testing.expect(it.next() == &one_a_pb.view);
testing.expect(it.next() == &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);
var it = ViewStack(View).iter(views.last, .reverse, @as(u32, 1 << 1), filters.current);
testing.expect(it.next() == &three_b_pa.view);
testing.expect(it.next() == &four_b.view);
testing.expect(it.next() == &five_b.view);
testing.expect(it.next() == null);
}
}