feat(dom): element generator

1 files changed, 150 insertions, 0 deletions

diff --git a/src/dom/Element.zig b/src/dom/Element.zig
new file mode 100644
index 0000000..ff8a3d1
--- /dev/null
+++ b/src/dom/Element.zig
@@ -0,0 +1,150 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const eql = std.mem.eql;
+
+pub const Kind = enum {
+    void,
+    content,
+    literal,
+};
+
+const Self = @This();
+
+kind: Kind,
+tag: ?[]const u8 = null,
+attributes: std.StringArrayHashMap([]const u8),
+class_list: std.BufSet,
+content: ?[]*Self = null,
+literal: ?[]const u8 = null,
+
+pub fn init(alloc: Allocator, knd: Kind, tag: []const u8) Self {
+    return .{
+        .kind = knd,
+        .tag = tag,
+        .attributes = .init(alloc),
+        .class_list = .init(alloc),
+    };
+}
+
+pub fn initLit(alloc: Allocator, literal: []const u8) Self {
+    return .{ .kind = .literal, .literal = literal, .attributes = .init(alloc), .class_list = .init(alloc) };
+}
+
+pub fn deinit(self: *Self) void {
+    self.attributes.deinit();
+    self.class_list.deinit();
+}
+
+pub fn render(self: *Self, alloc: Allocator) !std.ArrayList(u8) {
+    var attr = try self.renderAttribute(alloc);
+    defer attr.deinit(alloc);
+    var acc = try std.ArrayList(u8).initCapacity(alloc, 2);
+    errdefer acc.deinit(alloc);
+    if (self.tag) |tag| {
+        try acc.append(alloc, '<');
+        try acc.appendSlice(alloc, tag);
+        try acc.appendSlice(alloc, attr.items);
+        try acc.append(alloc, '>');
+    }
+    switch (self.kind) {
+        .void => return acc,
+        .content => {
+            if (self.content) |content| {
+                for (content) |it| {
+                    var sub = try it.render(alloc);
+                    defer sub.deinit(alloc);
+                    try acc.appendSlice(alloc, sub.items);
+                }
+            }
+        },
+        .literal => try acc.appendSlice(alloc, self.literal.?),
+    }
+    if (self.tag) |tag| {
+        try acc.appendSlice(alloc, "</");
+        try acc.appendSlice(alloc, tag);
+        try acc.append(alloc, '>');
+    }
+    return acc;
+}
+
+fn renderAttribute(self: *Self, alloc: Allocator) !std.ArrayList(u8) {
+    var iter = self.attributes.iterator();
+    if (iter.len == 0) return .empty;
+    var acc = try std.ArrayList(u8).initCapacity(alloc, 2);
+    errdefer acc.deinit(alloc);
+    try acc.append(alloc, ' ');
+    var i: usize = 0;
+    while (iter.next()) |it| : (i += 1) {
+        try acc.appendSlice(alloc, it.key_ptr.*);
+        try acc.appendSlice(alloc, "=\"");
+        // MISSING ESCAPING!!!
+        try acc.appendSlice(alloc, it.value_ptr.*);
+        try acc.append(alloc, '"');
+        if (i < iter.len - 1) try acc.append(alloc, ' ');
+    }
+    return acc;
+}
+
+pub fn setAttribute(self: *Self, k: []const u8, v: []const u8) !void {
+    try self.attributes.put(k, v);
+}
+
+pub fn removeAttribute(self: *Self, k: []const u8) void {
+    _ = self.attributes.orderedRemove(k);
+}
+
+pub fn hasAttribute(self: *Self, k: []const u8) bool {
+    return self.attributes.contains(k);
+}
+
+fn doTest(alloc: Allocator, el: *Self, exp: []const u8) !void {
+    var rendered = try el.render(alloc);
+    defer rendered.deinit(alloc);
+    std.testing.expect(eql(u8, rendered.items, exp)) catch |err| {
+        std.debug.print("{s}\n", .{rendered.items});
+        return err;
+    };
+}
+
+test "void element" {
+    var arena = std.heap.DebugAllocator(.{}).init;
+    defer _ = arena.deinit();
+    const alloc = arena.allocator();
+
+    var br = init(alloc, .void, "br");
+    defer br.deinit();
+
+    try doTest(alloc, &br, "<br>");
+
+    var img = init(alloc, .void, "img");
+    defer img.deinit();
+    try img.setAttribute("src", "foo");
+    try img.setAttribute("alt", "bar");
+
+    try doTest(alloc, &img, "<img src=\"foo\" alt=\"bar\">");
+}
+
+test "content element" {
+    var arena = std.heap.DebugAllocator(.{}).init;
+    defer _ = arena.deinit();
+    const alloc = arena.allocator();
+
+    var p = init(alloc, .content, "p");
+    defer p.deinit();
+
+    var content = initLit(alloc, "hello world");
+    defer content.deinit();
+    var in = [_]*Self{&content};
+    p.content = &in;
+
+    try doTest(alloc, &content, "hello world");
+    try doTest(alloc, &p, "<p>hello world</p>");
+
+    var div = init(alloc, .content, "div");
+    defer div.deinit();
+    try div.setAttribute("class", "foo-bar");
+    var in2 = [_]*Self{&p, &content};
+    div.content = &in2;
+
+    try doTest(alloc, &div, "<div class=\"foo-bar\"><p>hello world</p>hello world</div>");
+}