Add TextDecoder (utf8 support only)

Author: karlseguin

src/browser/encoding/TextDecoder.zig

@@ -0,0 +1,106 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <[email protected]>
+// Pierre Tachoire <[email protected]>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const log = @import("../../log.zig");
+
+const Env = @import("../env.zig").Env;
+
+// https://encoding.spec.whatwg.org/#interface-textdecoder
+const TextDecoder = @This();
+
+const SupportedLabels = enum {
+    utf8,
+    @"utf-8",
+    @"unicode-1-1-utf-8",
+};
+
+const Options = struct {
+    fatal: bool = false,
+    ignoreBOM: bool = false,
+};
+
+fatal: bool,
+ignore_bom: bool,
+
+pub fn constructor(label_: ?[]const u8, opts_: ?Options) !TextDecoder {
+    if (label_) |l| {
+        _ = std.meta.stringToEnum(SupportedLabels, l) orelse {
+            log.warn(.web_api, "not implemented", .{ .feature = "TextDecoder label", .label = l });
+            return error.NotImplemented;
+        };
+    }
+    const opts = opts_ orelse Options{};
+    return .{
+        .fatal = opts.fatal,
+        .ignore_bom = opts.ignoreBOM,
+    };
+}
+
+pub fn get_encoding(_: *const TextDecoder) []const u8 {
+    return "utf-8";
+}
+
+pub fn get_ignoreBOM(self: *const TextDecoder) bool {
+    return self.ignore_bom;
+}
+
+pub fn get_fatal(self: *const TextDecoder) bool {
+    return self.fatal;
+}
+
+// TODO: Should accept an ArrayBuffer, TypedArray or DataView
+// js.zig will currently only map a TypedArray to our []const u8.
+pub fn _decode(self: *const TextDecoder, v: []const u8) ![]const u8 {
+    if (self.fatal and !std.unicode.utf8ValidateSlice(v)) {
+        return error.InvalidUtf8;
+    }
+
+    if (self.ignore_bom == false and std.mem.startsWith(u8, v, &.{ 0xEF, 0xBB, 0xBF })) {
+        return v[3..];
+    }
+
+    return v;
+}
+
+const testing = @import("../../testing.zig");
+test "Browser.Encoding.TextDecoder" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{
+        .html = "",
+    });
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let d1 = new TextDecoder();", null },
+        .{ "d1.encoding;", "utf-8" },
+        .{ "d1.fatal", "false" },
+        .{ "d1.ignoreBOM", "false" },
+        .{ "d1.decode(new Uint8Array([240, 160, 174, 183]))", "𠮷" },
+        .{ "d1.decode(new Uint8Array([0xEF, 0xBB, 0xBF, 240, 160, 174, 183]))", "𠮷" },
+
+        .{ "let d2 = new TextDecoder('utf8', {fatal: true})", null },
+        .{
+            \\ try {
+            \\    let data  = new Uint8Array([240, 240, 160, 174, 183]);
+            \\    d2.decode(data);
+            \\ } catch (e) {e}
+            ,
+            "Error: InvalidUtf8",
+        },
+    }, .{});
+}

src/browser/encoding/text_encoder.zig renamed to src/browser/encoding/TextEncoder.zig

@@ -1,4 +1,4 @@
-// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
 //
 // Francis Bouvier <[email protected]>
 // Pierre Tachoire <[email protected]>
@@ -20,39 +20,37 @@ const std = @import("std");
 
 const Env = @import("../env.zig").Env;
 
-pub const Interfaces = .{
-    TextEncoder,
-};
-
 // https://encoding.spec.whatwg.org/#interface-textencoder
-pub const TextEncoder = struct {
-    pub fn constructor() !TextEncoder {
-        return .{};
-    }
+const TextEncoder = @This();
 
-    pub fn get_encoding(_: *const TextEncoder) []const u8 {
-        return "utf-8";
-    }
+pub fn constructor() !TextEncoder {
+    return .{};
+}
 
-    pub fn _encode(_: *const TextEncoder, v: []const u8) !Env.TypedArray(u8) {
-        // Ensure the input is a valid utf-8
-        // It seems chrome accepts invalid utf-8 sequence.
-        //
-        if (!std.unicode.utf8ValidateSlice(v)) {
-            return error.InvalidUtf8;
-        }
+pub fn get_encoding(_: *const TextEncoder) []const u8 {
+    return "utf-8";
+}
 
-        return .{ .values = v };
+pub fn _encode(_: *const TextEncoder, v: []const u8) !Env.TypedArray(u8) {
+    // Ensure the input is a valid utf-8
+    // It seems chrome accepts invalid utf-8 sequence.
+    //
+    if (!std.unicode.utf8ValidateSlice(v)) {
+        return error.InvalidUtf8;
     }
-};
+
+    return .{ .values = v };
+}
 
 const testing = @import("../../testing.zig");
 test "Browser.Encoding.TextEncoder" {
-    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{
+        .html = "",
+    });
     defer runner.deinit();
 
     try runner.testCases(&.{
-        .{ "var encoder = new TextEncoder();", "undefined" },
+        .{ "var encoder = new TextEncoder();", null },
         .{ "encoder.encoding;", "utf-8" },
         .{ "encoder.encode('€');", "226,130,172" },
 

src/browser/encoding/encoding.zig

@@ -0,0 +1,22 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <[email protected]>
+// Pierre Tachoire <[email protected]>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+pub const Interfaces = .{
+    @import("TextDecoder.zig"),
+    @import("TextEncoder.zig"),
+};

src/browser/env.zig

@@ -26,7 +26,7 @@ const WebApis = struct {
         @import("cssom/cssom.zig").Interfaces,
         @import("dom/dom.zig").Interfaces,
         @import("dom/shadow_root.zig").ShadowRoot,
-        @import("encoding/text_encoder.zig").Interfaces,
+        @import("encoding/encoding.zig").Interfaces,
         @import("events/event.zig").Interfaces,
         @import("html/html.zig").Interfaces,
         @import("iterator/iterator.zig").Interfaces,