Allow storing *View in ViewStack

This is done in preparation for implementing focus stacks.

src/command.zig

@@ -3,6 +3,7 @@ const c = @import("c.zig");
 
 const Log = @import("log.zig").Log;
 const Server = @import("server.zig").Server;
+const View = @import("view.zig").View;
 const ViewStack = @import("view_stack.zig").ViewStack;
 
 pub const Arg = union {
@@ -60,7 +61,7 @@ pub fn modifyMasterFactor(server: *Server, arg: Arg) void {
 pub fn zoom(server: *Server, arg: Arg) void {
     if (server.root.focused_view) |current_focus| {
         const output = server.root.focusedOutput();
-        const node = @fieldParentPtr(ViewStack.Node, "view", current_focus);
+        const node = @fieldParentPtr(ViewStack(View).Node, "view", current_focus);
         if (node != output.views.first) {
             output.views.remove(node);
             output.views.push(node);

src/output.zig

@@ -6,6 +6,7 @@ const Box = @import("box.zig").Box;
 const LayerSurface = @import("layer_surface.zig").LayerSurface;
 const Log = @import("log.zig").Log;
 const Root = @import("root.zig").Root;
+const View = @import("view.zig").View;
 const ViewStack = @import("view_stack.zig").ViewStack;
 
 pub const Output = struct {
@@ -22,7 +23,7 @@ pub const Output = struct {
     usable_box: Box,
 
     /// The top of the stack is the "most important" view.
-    views: ViewStack,
+    views: ViewStack(View),
 
     /// A bit field of focused tags
     current_focused_tags: u32,
@@ -100,7 +101,7 @@ pub const Output = struct {
     /// Add a new view to the output. arrangeViews() will be called by the view
     /// when it is mapped.
     pub fn addView(self: *Self, wlr_xdg_surface: *c.wlr_xdg_surface) void {
-        const node = self.root.server.allocator.create(ViewStack.Node) catch unreachable;
+        const node = self.root.server.allocator.create(ViewStack(View).Node) catch unreachable;
         node.view.init(self, wlr_xdg_surface, self.current_focused_tags);
         self.views.push(node);
     }
@@ -129,7 +130,7 @@ pub const Output = struct {
 
         const visible_count = blk: {
             var count: u32 = 0;
-            var it = ViewStack.pendingIterator(self.views.first, output_tags);
+            var it = ViewStack(View).pendingIterator(self.views.first, output_tags);
             while (it.next() != null) count += 1;
             break :blk count;
         };
@@ -157,8 +158,9 @@ pub const Output = struct {
         }
 
         var i: u32 = 0;
-        var it = ViewStack.pendingIterator(self.views.first, output_tags);
+        var it = ViewStack(View).pendingIterator(self.views.first, output_tags);
-        while (it.next()) |view| {
+        while (it.next()) |node| {
+            const view = &node.view;
             if (i < master_count) {
                 // Add the remainder to the first master to ensure every pixel of height is used
                 const master_height = @divTrunc(layout_height, master_count);

src/render.zig

@@ -44,8 +44,9 @@ pub fn renderOutput(output: *Output) void {
     renderLayer(output.*, output.layers[c.ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM], &now, ox, oy);
 
     // The first view in the list is "on top" so iterate in reverse.
-    var it = ViewStack.reverseIterator(output.views.last, output.current_focused_tags);
+    var it = ViewStack(View).reverseIterator(output.views.last, output.current_focused_tags);
-    while (it.next()) |view| {
+    while (it.next()) |node| {
+        const view = &node.view;
         // This check prevents a race condition when a frame is requested
         // between mapping of a view and the first configure being handled.
         if (view.current_box.width == 0 or view.current_box.height == 0) {

src/root.zig

@@ -71,10 +71,10 @@ pub const Root = struct {
         var output_it = self.outputs.first;
         while (output_it) |node| : (output_it = node.next) {
             const output = &node.data;
-            var view_it = ViewStack.iterator(output.views.first, 0xFFFFFFFF);
+            var view_it = ViewStack(View).iterator(output.views.first, 0xFFFFFFFF);
-            while (view_it.next()) |view| {
+            while (view_it.next()) |view_node| {
-                if (view.isAt(lx, ly, surface, sx, sy)) {
+                if (view_node.view.isAt(lx, ly, surface, sx, sy)) {
-                    return view;
+                    return &view_node.view;
                 }
             }
         }
@@ -95,22 +95,22 @@ pub const Root = struct {
         const output = self.focusedOutput();
         if (self.focused_view) |current_focus| {
             // If there is a currently focused view, focus the next visible view in the stack.
-            const current_node = @fieldParentPtr(ViewStack.Node, "view", current_focus);
+            const current_node = @fieldParentPtr(ViewStack(View).Node, "view", current_focus);
-            var it = ViewStack.iterator(current_node, output.current_focused_tags);
+            var it = ViewStack(View).iterator(current_node, output.current_focused_tags);
             // Skip past the current node
             _ = it.next();
             // Focus the next visible node if there is one
-            if (it.next()) |view| {
+            if (it.next()) |node| {
-                view.focus(view.wlr_xdg_surface.surface);
+                node.view.focus(node.view.wlr_xdg_surface.surface);
                 return;
             }
         }
 
         // There is either no currently focused view or the last visible view in the
         // stack is focused and we need to wrap.
-        var it = ViewStack.iterator(output.views.first, output.current_focused_tags);
+        var it = ViewStack(View).iterator(output.views.first, output.current_focused_tags);
-        if (it.next()) |view| {
+        if (it.next()) |node| {
-            view.focus(view.wlr_xdg_surface.surface);
+            node.view.focus(node.view.wlr_xdg_surface.surface);
         } else {
             // Otherwise clear the focus since there are no visible views
             self.clearFocus();
@@ -123,22 +123,22 @@ pub const Root = struct {
         const output = self.focusedOutput();
         if (self.focused_view) |current_focus| {
             // If there is a currently focused view, focus the previous visible view in the stack.
-            const current_node = @fieldParentPtr(ViewStack.Node, "view", current_focus);
+            const current_node = @fieldParentPtr(ViewStack(View).Node, "view", current_focus);
-            var it = ViewStack.reverseIterator(current_node, output.current_focused_tags);
+            var it = ViewStack(View).reverseIterator(current_node, output.current_focused_tags);
             // Skip past the current node
             _ = it.next();
             // Focus the previous visible node if there is one
-            if (it.next()) |view| {
+            if (it.next()) |node| {
-                view.focus(view.wlr_xdg_surface.surface);
+                node.view.focus(node.view.wlr_xdg_surface.surface);
                 return;
             }
         }
 
         // There is either no currently focused view or the first visible view in the
         // stack is focused and we need to wrap.
-        var it = ViewStack.reverseIterator(output.views.last, output.current_focused_tags);
+        var it = ViewStack(View).reverseIterator(output.views.last, output.current_focused_tags);
-        if (it.next()) |view| {
+        if (it.next()) |node| {
-            view.focus(view.wlr_xdg_surface.surface);
+            node.view.focus(node.view.wlr_xdg_surface.surface);
         } else {
             // Otherwise clear the focus since there are no visible views
             self.clearFocus();
@@ -166,8 +166,9 @@ pub const Root = struct {
         var output_it = self.outputs.first;
         while (output_it) |node| : (output_it = node.next) {
             const output = &node.data;
-            var view_it = ViewStack.iterator(output.views.first, 0xFFFFFFFF);
+            var view_it = ViewStack(View).iterator(output.views.first, 0xFFFFFFFF);
-            while (view_it.next()) |view| {
+            while (view_it.next()) |view_node| {
+                const view = &view_node.view;
                 // Clear the serial in case this transaction is interrupting a prior one.
                 view.pending_serial = null;
 
@@ -259,8 +260,9 @@ pub const Root = struct {
                 self.focusNextView();
             }
 
-            var view_it = ViewStack.iterator(output.views.first, 0xFFFFFFFF);
+            var view_it = ViewStack(View).iterator(output.views.first, 0xFFFFFFFF);
-            while (view_it.next()) |view| {
+            while (view_it.next()) |view_node| {
+                const view = &view_node.view;
                 // Ensure that all pending state is cleared
                 view.pending_serial = null;
                 if (view.pending_box) |state| {

src/view.zig

@@ -156,7 +156,7 @@ pub const View = struct {
         const view = @fieldParentPtr(View, "listen_destroy", listener.?);
         const output = view.output;
 
-        const node = @fieldParentPtr(ViewStack.Node, "view", view);
+        const node = @fieldParentPtr(ViewStack(View).Node, "view", view);
         output.views.remove(node);
         output.root.server.allocator.destroy(node);
     }

src/view_stack.zig

@@ -1,8 +1,12 @@
 const View = @import("view.zig").View;
 
 /// A specialized doubly-linked stack that allows for filtered iteration
-/// over the nodes
+/// over the nodes. T must be View or *View.
-pub const ViewStack = struct {
+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 {
@@ -11,7 +15,7 @@ pub const ViewStack = struct {
             next: ?*Node,
 
             /// The view stored in this node
-        view: View,
+            view: T,
         };
 
         /// Top/bottom nodes in the stack
@@ -69,7 +73,7 @@ pub const ViewStack = struct {
 
             /// 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) ?*View {
+            pub fn next(self: *Iterator) ?*Node {
                 while (self.it) |node| : (self.it = if (self.reverse) node.prev else node.next) {
                     if (node.view.mapped and if (self.pending)
                         if (node.view.pending_tags) |pending_tags|
@@ -78,9 +82,8 @@ pub const ViewStack = struct {
                             self.tags & node.view.current_tags != 0
                     else
                         self.tags & node.view.current_tags != 0) {
-                    const ret = &node.view;
                         self.it = if (self.reverse) node.prev else node.next;
-                    return ret;
+                        return node;
                     }
                 }
                 return null;
@@ -124,24 +127,25 @@ pub const ViewStack = struct {
             };
         }
     };
+}
 
 const testing = @import("std").testing;
 
-test "push/remove" {
+test "push/remove (*View)" {
     const allocator = testing.allocator;
 
-    var views: ViewStack = undefined;
+    var views: ViewStack(*View) = undefined;
     views.init();
 
-    const one = try allocator.create(ViewStack.Node);
+    const one = try allocator.create(ViewStack(*View).Node);
     defer allocator.destroy(one);
-    const two = try allocator.create(ViewStack.Node);
+    const two = try allocator.create(ViewStack(*View).Node);
     defer allocator.destroy(two);
-    const three = try allocator.create(ViewStack.Node);
+    const three = try allocator.create(ViewStack(*View).Node);
     defer allocator.destroy(three);
-    const four = try allocator.create(ViewStack.Node);
+    const four = try allocator.create(ViewStack(*View).Node);
     defer allocator.destroy(four);
-    const five = try allocator.create(ViewStack.Node);
+    const five = try allocator.create(ViewStack(*View).Node);
     defer allocator.destroy(five);
 
     views.push(three); // {3}
@@ -255,40 +259,40 @@ test "push/remove" {
     testing.expect(views.last == null);
 }
 
-test "iteration" {
+test "iteration (View)" {
     const allocator = testing.allocator;
 
-    var views: ViewStack = undefined;
+    var views: ViewStack(View) = undefined;
     views.init();
 
-    const one_a_pb = try allocator.create(ViewStack.Node);
+    const one_a_pb = try allocator.create(ViewStack(View).Node);
     defer allocator.destroy(one_a_pb);
     one_a_pb.view.mapped = true;
     one_a_pb.view.current_tags = 1 << 0;
     one_a_pb.view.pending_tags = 1 << 1;
 
-    const two_a = try allocator.create(ViewStack.Node);
+    const two_a = try allocator.create(ViewStack(View).Node);
     defer allocator.destroy(two_a);
     two_a.view.mapped = true;
     two_a.view.current_tags = 1 << 0;
 
-    const three_b_pa = try allocator.create(ViewStack.Node);
+    const three_b_pa = try allocator.create(ViewStack(View).Node);
     defer allocator.destroy(three_b_pa);
     three_b_pa.view.mapped = true;
     three_b_pa.view.current_tags = 1 << 1;
     three_b_pa.view.pending_tags = 1 << 0;
 
-    const four_b = try allocator.create(ViewStack.Node);
+    const four_b = try allocator.create(ViewStack(View).Node);
     defer allocator.destroy(four_b);
     four_b.view.mapped = true;
     four_b.view.current_tags = 1 << 1;
 
-    const five_b = try allocator.create(ViewStack.Node);
+    const five_b = try allocator.create(ViewStack(View).Node);
     defer allocator.destroy(five_b);
     five_b.view.mapped = true;
     five_b.view.current_tags = 1 << 1;
 
-    const unmapped_1 = try allocator.create(ViewStack.Node);
+    const unmapped_1 = try allocator.create(ViewStack(View).Node);
     defer allocator.destroy(unmapped_1);
     unmapped_1.view.mapped = false;
 
@@ -301,92 +305,92 @@ test "iteration" {
 
     // Iteration over all tags
     {
-        var it = ViewStack.iterator(views.first, 0xFFFFFFFF);
+        var it = ViewStack(View).iterator(views.first, 0xFFFFFFFF);
-        testing.expect(it.next() == &two_a.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &two_a.view);
-        testing.expect(it.next() == &five_b.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &five_b.view);
-        testing.expect(it.next() == &four_b.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
-        testing.expect(it.next() == &one_a_pb.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &one_a_pb.view);
-        testing.expect(it.next() == &three_b_pa.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.iterator(views.first, 1 << 0);
+        var it = ViewStack(View).iterator(views.first, 1 << 0);
-        testing.expect(it.next() == &two_a.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &two_a.view);
-        testing.expect(it.next() == &one_a_pb.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.iterator(views.first, 1 << 1);
+        var it = ViewStack(View).iterator(views.first, 1 << 1);
-        testing.expect(it.next() == &five_b.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &five_b.view);
-        testing.expect(it.next() == &four_b.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
-        testing.expect(it.next() == &three_b_pa.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.iterator(views.first, 1 << 2);
+        var it = ViewStack(View).iterator(views.first, 1 << 2);
         testing.expect(it.next() == null);
     }
 
     // Reverse iteration over all tags
     {
-        var it = ViewStack.reverseIterator(views.last, 0xFFFFFFFF);
+        var it = ViewStack(View).reverseIterator(views.last, 0xFFFFFFFF);
-        testing.expect(it.next() == &three_b_pa.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &three_b_pa.view);
-        testing.expect(it.next() == &one_a_pb.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &one_a_pb.view);
-        testing.expect(it.next() == &four_b.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
-        testing.expect(it.next() == &five_b.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &five_b.view);
-        testing.expect(it.next() == &two_a.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.reverseIterator(views.last, 1 << 0);
+        var it = ViewStack(View).reverseIterator(views.last, 1 << 0);
-        testing.expect(it.next() == &one_a_pb.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &one_a_pb.view);
-        testing.expect(it.next() == &two_a.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.reverseIterator(views.last, 1 << 1);
+        var it = ViewStack(View).reverseIterator(views.last, 1 << 1);
-        testing.expect(it.next() == &three_b_pa.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &three_b_pa.view);
-        testing.expect(it.next() == &four_b.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
-        testing.expect(it.next() == &five_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.reverseIterator(views.first, 1 << 2);
+        var it = ViewStack(View).reverseIterator(views.first, 1 << 2);
         testing.expect(it.next() == null);
     }
 
     // Iteration over (pending) 'a' tags
     {
-        var it = ViewStack.pendingIterator(views.first, 1 << 0);
+        var it = ViewStack(View).pendingIterator(views.first, 1 << 0);
-        testing.expect(it.next() == &two_a.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &two_a.view);
-        testing.expect(it.next() == &three_b_pa.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.pendingIterator(views.first, 1 << 1);
+        var it = ViewStack(View).pendingIterator(views.first, 1 << 1);
-        testing.expect(it.next() == &five_b.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &five_b.view);
-        testing.expect(it.next() == &four_b.view);
+        testing.expect((if (it.next()) |node| &node.view else null) == &four_b.view);
-        testing.expect(it.next() == &one_a_pb.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.pendingIterator(views.first, 1 << 2);
+        var it = ViewStack(View).pendingIterator(views.first, 1 << 2);
         testing.expect(it.next() == null);
     }
 }