Better CDP node serialization

Include direct descendant, with hooks for other serialization options.

Don't include parentId if null.

src/cdp/Node.zig

@@ -44,50 +44,8 @@ const CompatibilityMode = enum {
     NoQuirksMode,
 };
 
-pub fn jsonStringify(self: *const Node, writer: anytype) !void {
+pub fn writer(self: *const Node, opts: Writer.Opts) Writer {
-    try writer.beginObject();
+    return .{ .node = self, .opts = opts };
-    try writer.objectField("nodeId");
-    try writer.write(self.id);
-
-    try writer.objectField("parentId");
-    try writer.write(self.parent_id);
-
-    try writer.objectField("backendNodeId");
-    try writer.write(self.backend_node_id);
-
-    try writer.objectField("nodeType");
-    try writer.write(self.node_type);
-
-    try writer.objectField("nodeName");
-    try writer.write(self.node_name);
-
-    try writer.objectField("localName");
-    try writer.write(self.local_name);
-
-    try writer.objectField("nodeValue");
-    try writer.write(self.node_value);
-
-    try writer.objectField("childNodeCount");
-    try writer.write(self.child_node_count);
-
-    try writer.objectField("children");
-    try writer.write(self.children);
-
-    try writer.objectField("documentURL");
-    try writer.write(self.document_url);
-
-    try writer.objectField("baseURL");
-    try writer.write(self.base_url);
-
-    try writer.objectField("xmlVersion");
-    try writer.write(self.xml_version);
-
-    try writer.objectField("compatibilityMode");
-    try writer.write(self.compatibility_mode);
-
-    try writer.objectField("isScrollable");
-    try writer.write(self.is_scrollable);
-    try writer.endObject();
 }
 
 // Whenever we send a node to the client, we register it here for future lookup.
@@ -95,6 +53,7 @@ pub fn jsonStringify(self: *const Node, writer: anytype) !void {
 pub const Registry = struct {
     node_id: u32,
     allocator: Allocator,
+    arena: std.heap.ArenaAllocator,
     node_pool: std.heap.MemoryPool(Node),
     lookup_by_id: std.AutoHashMapUnmanaged(Id, *Node),
     lookup_by_node: std.HashMapUnmanaged(*parser.Node, *Node, NodeContext, std.hash_map.default_max_load_percentage),
@@ -102,9 +61,10 @@ pub const Registry = struct {
     pub fn init(allocator: Allocator) Registry {
         return .{
             .node_id = 0,
-            .allocator = allocator,
             .lookup_by_id = .{},
             .lookup_by_node = .{},
+            .allocator = allocator,
+            .arena = std.heap.ArenaAllocator.init(allocator),
             .node_pool = std.heap.MemoryPool(Node).init(allocator),
         };
     }
@@ -114,12 +74,14 @@ pub const Registry = struct {
         self.lookup_by_id.deinit(allocator);
         self.lookup_by_node.deinit(allocator);
         self.node_pool.deinit();
+        self.arena.deinit();
     }
 
     pub fn reset(self: *Registry) void {
         self.lookup_by_id.clearRetainingCapacity();
         self.lookup_by_node.clearRetainingCapacity();
-        _ = self.node_pool.reset(.{ .retain_capacity = {} });
+        _ = self.arena.reset(.{ .retain_with_limit = 1024 });
+        _ = self.node_pool.reset(.{ .retain_with_limit = 1024 });
     }
 
     pub fn register(self: *Registry, n: *parser.Node) !*Node {
@@ -132,11 +94,10 @@ pub const Registry = struct {
         // but, just in case, let's try to keep things tidy.
         errdefer _ = self.lookup_by_node.remove(n);
 
-        const children = try parser.nodeGetChildNodes(n);
-        const children_count = try parser.nodeListLength(children);
-
         const id = self.node_id;
-        defer self.node_id = id + 1;
+        self.node_id = id + 1;
+
+        const child_nodes = try self.registerChildNodes(n);
 
         const node = try self.node_pool.create();
         errdefer self.node_pool.destroy(node);
@@ -146,12 +107,12 @@ pub const Registry = struct {
             .id = id,
             .parent_id = null, // TODO
             .backend_node_id = id, // ??
-            .node_name = try parser.nodeName(n),
+            .node_name = parser.nodeName(n) catch return error.NodeNameError,
-            .local_name = try parser.nodeLocalName(n),
+            .local_name = parser.nodeLocalName(n) catch return error.NodeLocalNameError,
-            .node_value = try parser.nodeValue(n) orelse "",
+            .node_value = (parser.nodeValue(n) catch return error.NameValueError) orelse "",
-            .node_type = @intFromEnum(try parser.nodeType(n)),
+            .node_type = @intFromEnum(parser.nodeType(n) catch return error.NodeTypeError),
-            .child_node_count = children_count,
+            .child_node_count = @intCast(child_nodes.len),
-            .children = &.{}, // TODO
+            .children = child_nodes,
             .document_url = null,
             .base_url = null,
             .xml_version = "",
@@ -168,6 +129,31 @@ pub const Registry = struct {
         try self.lookup_by_id.putNoClobber(self.allocator, id, node);
         return node;
     }
+
+    pub fn registerChildNodes(self: *Registry, n: *parser.Node) RegisterError![]*Node {
+        const node_list = parser.nodeGetChildNodes(n) catch return error.GetChildNodeError;
+        const count = parser.nodeListLength(node_list) catch return error.NodeListLengthError;
+
+        var arr = try self.arena.allocator().alloc(*Node, count);
+        var i: usize = 0;
+        for (0..count) |_| {
+            const child = (parser.nodeListItem(node_list, @intCast(i)) catch return error.NodeListItemError) orelse continue;
+            arr[i] = try self.register(child);
+            i += 1;
+        }
+        return arr[0..i];
+    }
+};
+
+const RegisterError = error{
+    OutOfMemory,
+    GetChildNodeError,
+    NodeListLengthError,
+    NodeListItemError,
+    NodeNameError,
+    NodeLocalNameError,
+    NameValueError,
+    NodeTypeError,
 };
 
 const NodeContext = struct {
@@ -271,8 +257,76 @@ pub const Search = struct {
     };
 };
 
+// Need a custom writer, because we can't just serialize the node as-is.
+// Sometimes we want to serializ the node without chidren, sometimes with just
+// its direct children, and sometimes the entire tree.
+// (For now, we only support direct children)
+pub const Writer = struct {
+    opts: Opts,
+    node: *const Node,
+
+    pub const Opts = struct {};
+
+    pub fn jsonStringify(self: *const Writer, w: anytype) !void {
+        try w.beginObject();
+        try writeCommon(self.node, w);
+        try w.objectField("children");
+        try w.beginArray();
+        for (self.node.children) |node| {
+            try w.beginObject();
+            try writeCommon(node, w);
+            try w.endObject();
+        }
+        try w.endArray();
+        try w.endObject();
+    }
+
+    fn writeCommon(node: *const Node, w: anytype) !void {
+        try w.objectField("nodeId");
+        try w.write(node.id);
+
+        if (node.parent_id) |pid| {
+            try w.objectField("parentId");
+            try w.write(pid);
+        }
+
+        try w.objectField("backendNodeId");
+        try w.write(node.backend_node_id);
+
+        try w.objectField("nodeType");
+        try w.write(node.node_type);
+
+        try w.objectField("nodeName");
+        try w.write(node.node_name);
+
+        try w.objectField("localName");
+        try w.write(node.local_name);
+
+        try w.objectField("nodeValue");
+        try w.write(node.node_value);
+
+        try w.objectField("childNodeCount");
+        try w.write(node.child_node_count);
+
+        try w.objectField("documentURL");
+        try w.write(node.document_url);
+
+        try w.objectField("baseURL");
+        try w.write(node.base_url);
+
+        try w.objectField("xmlVersion");
+        try w.write(node.xml_version);
+
+        try w.objectField("compatibilityMode");
+        try w.write(node.compatibility_mode);
+
+        try w.objectField("isScrollable");
+        try w.write(node.is_scrollable);
+    }
+};
+
 const testing = @import("testing.zig");
-test "CDP Node: Registry register" {
+test "cdp Node: Registry register" {
     var registry = Registry.init(testing.allocator);
     defer registry.deinit();
 
@@ -298,7 +352,8 @@ test "CDP Node: Registry register" {
         try testing.expectEqual("a", node.local_name);
         try testing.expectEqual("", node.node_value);
         try testing.expectEqual(1, node.child_node_count);
-        try testing.expectEqual(0, node.children.len);
+        try testing.expectEqual(1, node.children.len);
+        try testing.expectEqual(1, node.children[0].id);
         try testing.expectEqual(null, node.document_url);
         try testing.expectEqual(null, node.base_url);
         try testing.expectEqual("", node.xml_version);
@@ -310,20 +365,21 @@ test "CDP Node: Registry register" {
     {
         const n = (try doc.querySelector("p")).?;
         const node = try registry.register(n);
-        const n1b = registry.lookup_by_id.get(1).?;
+        const n1b = registry.lookup_by_id.get(2).?;
         const n1c = registry.lookup_by_node.get(node._node).?;
         try testing.expectEqual(node, n1b);
         try testing.expectEqual(node, n1c);
 
-        try testing.expectEqual(1, node.id);
+        try testing.expectEqual(2, node.id);
         try testing.expectEqual(null, node.parent_id);
         try testing.expectEqual(1, node.node_type);
-        try testing.expectEqual(1, node.backend_node_id);
+        try testing.expectEqual(2, node.backend_node_id);
         try testing.expectEqual("P", node.node_name);
         try testing.expectEqual("p", node.local_name);
         try testing.expectEqual("", node.node_value);
         try testing.expectEqual(1, node.child_node_count);
-        try testing.expectEqual(0, node.children.len);
+        try testing.expectEqual(1, node.children.len);
+        try testing.expectEqual(3, node.children[0].id);
         try testing.expectEqual(null, node.document_url);
         try testing.expectEqual(null, node.base_url);
         try testing.expectEqual("", node.xml_version);
@@ -333,7 +389,7 @@ test "CDP Node: Registry register" {
     }
 }
 
-test "CDP Node: search list" {
+test "cdp Node: search list" {
     var registry = Registry.init(testing.allocator);
     defer registry.deinit();
 
@@ -383,3 +439,27 @@ test "CDP Node: search list" {
         try testing.expectEqual(2, registry.lookup_by_node.count());
     }
 }
+
+test "cdp Node: Writer" {
+    var registry = Registry.init(testing.allocator);
+    defer registry.deinit();
+
+    var doc = try testing.Document.init("<a id=a1></a><a id=a2></a>");
+    defer doc.deinit();
+
+    {
+        const node = try registry.register(doc.asNode());
+        const json = try std.json.stringifyAlloc(testing.allocator, node.writer(.{}), .{});
+        defer testing.allocator.free(json);
+
+        try testing.expectJson(.{ .nodeId = 0, .backendNodeId = 0, .nodeType = 9, .nodeName = "#document", .localName = "", .nodeValue = "", .documentURL = null, .baseURL = null, .xmlVersion = "", .isScrollable = false, .compatibilityMode = "NoQuirksMode", .childNodeCount = 1, .children = &.{.{ .nodeId = 1, .backendNodeId = 1, .nodeType = 1, .nodeName = "HTML", .localName = "html", .nodeValue = "", .childNodeCount = 2, .documentURL = null, .baseURL = null, .xmlVersion = "", .compatibilityMode = "NoQuirksMode", .isScrollable = false }} }, json);
+    }
+
+    {
+        const node = registry.lookup_by_id.get(1).?;
+        const json = try std.json.stringifyAlloc(testing.allocator, node.writer(.{}), .{});
+        defer testing.allocator.free(json);
+
+        try testing.expectJson(.{ .nodeId = 1, .backendNodeId = 1, .nodeType = 1, .nodeName = "HTML", .localName = "html", .nodeValue = "", .childNodeCount = 2, .documentURL = null, .baseURL = null, .xmlVersion = "", .compatibilityMode = "NoQuirksMode", .isScrollable = false, .children = &.{ .{ .nodeId = 2, .backendNodeId = 2, .nodeType = 1, .nodeName = "HEAD", .localName = "head", .nodeValue = "", .childNodeCount = 0, .documentURL = null, .baseURL = null, .xmlVersion = "", .compatibilityMode = "NoQuirksMode", .isScrollable = false }, .{ .nodeId = 3, .backendNodeId = 3, .nodeType = 1, .nodeName = "BODY", .localName = "body", .nodeValue = "", .childNodeCount = 2, .documentURL = null, .baseURL = null, .xmlVersion = "", .compatibilityMode = "NoQuirksMode", .isScrollable = false } } }, json);
+    }
+}

src/cdp/domains/dom.zig

@@ -51,9 +51,7 @@ fn getDocument(cmd: anytype) !void {
     const doc = page.doc orelse return error.DocumentNotLoaded;
 
     const node = try bc.node_registry.register(parser.documentToNode(doc));
-    return cmd.sendResult(.{
+    return cmd.sendResult(.{ .root = node.writer(.{}) }, .{});
-        .root = node,
-    }, .{});
 }
 
 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-performSearch
@@ -118,6 +116,7 @@ fn getSearchResults(cmd: anytype) !void {
 }
 
 const testing = @import("../testing.zig");
+
 test "cdp.dom: getSearchResults unknown search id" {
     var ctx = testing.context();
     defer ctx.deinit();
@@ -149,7 +148,7 @@ test "cdp.dom: search flow" {
             .method = "DOM.getSearchResults",
             .params = .{ .searchId = "0", .fromIndex = 0, .toIndex = 2 },
         });
-        try ctx.expectSentResult(.{ .nodeIds = &.{ 0, 1 } }, .{ .id = 13 });
+        try ctx.expectSentResult(.{ .nodeIds = &.{ 0, 2 } }, .{ .id = 13 });
 
         // different fromIndex
         try ctx.processMessage(.{
@@ -157,7 +156,7 @@ test "cdp.dom: search flow" {
             .method = "DOM.getSearchResults",
             .params = .{ .searchId = "0", .fromIndex = 1, .toIndex = 2 },
         });
-        try ctx.expectSentResult(.{ .nodeIds = &.{1} }, .{ .id = 14 });
+        try ctx.expectSentResult(.{ .nodeIds = &.{2} }, .{ .id = 14 });
 
         // different toIndex
         try ctx.processMessage(.{

src/cdp/testing.zig

@@ -26,11 +26,12 @@ const main = @import("cdp.zig");
 const parser = @import("netsurf");
 const App = @import("../app.zig").App;
 
-pub const allocator = @import("../testing.zig").allocator;
+const base = @import("../testing.zig");
-
+pub const allocator = base.allocator;
-pub const expectEqual = @import("../testing.zig").expectEqual;
+pub const expectJson = base.expectJson;
-pub const expectError = @import("../testing.zig").expectError;
+pub const expectEqual = base.expectEqual;
-pub const expectEqualSlices = @import("../testing.zig").expectEqualSlices;
+pub const expectError = base.expectError;
+pub const expectEqualSlices = base.expectEqualSlices;
 
 pub const Document = @import("../testing.zig").Document;
 
@@ -310,47 +311,5 @@ pub fn context() TestContext {
 fn compareExpectedToSent(expected: []const u8, actual: json.Value) !bool {
     const expected_value = try std.json.parseFromSlice(json.Value, std.testing.allocator, expected, .{});
     defer expected_value.deinit();
-    return compareJsonValues(expected_value.value, actual);
+    return base.isEqualJson(expected_value.value, actual);
-}
-
-fn compareJsonValues(a: std.json.Value, b: std.json.Value) bool {
-    if (!std.mem.eql(u8, @tagName(a), @tagName(b))) {
-        return false;
-    }
-
-    switch (a) {
-        .null => return true,
-        .bool => return a.bool == b.bool,
-        .integer => return a.integer == b.integer,
-        .float => return a.float == b.float,
-        .number_string => return std.mem.eql(u8, a.number_string, b.number_string),
-        .string => return std.mem.eql(u8, a.string, b.string),
-        .array => {
-            const a_len = a.array.items.len;
-            const b_len = b.array.items.len;
-            if (a_len != b_len) {
-                return false;
-            }
-            for (a.array.items, b.array.items) |a_item, b_item| {
-                if (compareJsonValues(a_item, b_item) == false) {
-                    return false;
-                }
-            }
-            return true;
-        },
-        .object => {
-            var it = a.object.iterator();
-            while (it.next()) |entry| {
-                const key = entry.key_ptr.*;
-                if (b.object.get(key)) |b_item| {
-                    if (compareJsonValues(entry.value_ptr.*, b_item) == false) {
-                        return false;
-                    }
-                } else {
-                    return false;
-                }
-            }
-            return true;
-        },
-    }
 }

src/testing.zig

@@ -17,14 +17,15 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
-const parser = @import("netsurf");
 
+const parser = @import("netsurf");
 pub const allocator = std.testing.allocator;
 pub const expectError = std.testing.expectError;
 pub const expectString = std.testing.expectEqualStrings;
 pub const expectEqualSlices = std.testing.expectEqualSlices;
 
 const App = @import("app.zig").App;
+const Allocator = std.mem.Allocator;
 
 // Merged std.testing.expectEqual and std.testing.expectString
 // can be useful when testing fields of an anytype an you don't know
@@ -217,12 +218,93 @@ pub const Document = struct {
 
     pub fn querySelectorAll(self: *Document, selector: []const u8) ![]const *parser.Node {
         const css = @import("dom/css.zig");
-        const node_list = try css.querySelectorAll(self.arena.allocator(), parser.documentToNode(self.doc), selector);
+        const node_list = try css.querySelectorAll(self.arena.allocator(), self.asNode(), selector);
         return node_list.nodes.items;
     }
 
     pub fn querySelector(self: *Document, selector: []const u8) !?*parser.Node {
         const css = @import("dom/css.zig");
-        return css.querySelector(self.arena.allocator(), parser.documentToNode(self.doc), selector);
+        return css.querySelector(self.arena.allocator(), self.asNode(), selector);
+    }
+
+    pub fn asNode(self: *const Document) *parser.Node {
+        return parser.documentToNode(self.doc);
     }
 };
+
+pub fn expectJson(a: anytype, b: anytype) !void {
+    var arena = std.heap.ArenaAllocator.init(allocator);
+    defer arena.deinit();
+
+    const aa = arena.allocator();
+
+    const a_value = try convertToJson(aa, a);
+    const b_value = try convertToJson(aa, b);
+
+    errdefer {
+        const a_json = std.json.stringifyAlloc(aa, a_value, .{ .whitespace = .indent_2 }) catch unreachable;
+        const b_json = std.json.stringifyAlloc(aa, b_value, .{ .whitespace = .indent_2 }) catch unreachable;
+        std.debug.print("== Expected ==\n{s}\n\n== Actual ==\n{s}", .{ a_json, b_json });
+    }
+
+    try expectJsonValue(a_value, b_value);
+}
+
+pub fn isEqualJson(a: anytype, b: anytype) !bool {
+    var arena = std.heap.ArenaAllocator.init(allocator);
+    defer arena.deinit();
+
+    const aa = arena.allocator();
+    const a_value = try convertToJson(aa, a);
+    const b_value = try convertToJson(aa, b);
+    expectJsonValue(a_value, b_value) catch return false;
+    return true;
+}
+
+fn convertToJson(arena: Allocator, value: anytype) !std.json.Value {
+    const T = @TypeOf(value);
+    if (T == std.json.Value) {
+        return value;
+    }
+
+    var str: []const u8 = undefined;
+    if (T == []u8 or T == []const u8 or comptime isStringArray(T)) {
+        str = value;
+    } else {
+        str = try std.json.stringifyAlloc(arena, value, .{});
+    }
+    return std.json.parseFromSliceLeaky(std.json.Value, arena, str, .{});
+}
+
+fn expectJsonValue(a: std.json.Value, b: std.json.Value) !void {
+    try expectEqual(@tagName(a), @tagName(b));
+
+    // at this point, we know that if a is an int, b must also be an int
+    switch (a) {
+        .null => return,
+        .bool => try expectEqual(a.bool, b.bool),
+        .integer => try expectEqual(a.integer, b.integer),
+        .float => try expectEqual(a.float, b.float),
+        .number_string => try expectEqual(a.number_string, b.number_string),
+        .string => try expectEqual(a.string, b.string),
+        .array => {
+            const a_len = a.array.items.len;
+            const b_len = b.array.items.len;
+            try expectEqual(a_len, b_len);
+            for (a.array.items, b.array.items) |a_item, b_item| {
+                try expectJsonValue(a_item, b_item);
+            }
+        },
+        .object => {
+            var it = a.object.iterator();
+            while (it.next()) |entry| {
+                const key = entry.key_ptr.*;
+                if (b.object.get(key)) |b_item| {
+                    try expectJsonValue(entry.value_ptr.*, b_item);
+                } else {
+                    return error.MissingKey;
+                }
+            }
+        },
+    }
+}