LibIDL+LibWeb: Move parse_exposure_set from code generator to LibIDL

Author: https://github.com/bplaat
Commit: da620d6ccf
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4535
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/trflynn89

Libraries/LibIDL/ExposedTo.cpp

@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2022, Andrew Kaster <akaster@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibIDL/ExposedTo.h>
+
+static ByteString s_error_string;
+
+namespace IDL {
+
+ErrorOr<ExposedTo> parse_exposure_set(StringView interface_name, StringView exposed)
+{
+    // NOTE: This roughly follows the definitions of https://webidl.spec.whatwg.org/#Exposed
+    //       It does not remotely interpret all the abstract operations therein though.
+
+    auto exposed_trimmed = exposed.trim_whitespace();
+    if (exposed_trimmed == "*"sv)
+        return ExposedTo::All;
+    if (exposed_trimmed == "Nobody"sv)
+        return ExposedTo::Nobody;
+    if (exposed_trimmed == "Window"sv)
+        return ExposedTo::Window;
+    if (exposed_trimmed == "Worker"sv)
+        return ExposedTo::AllWorkers;
+    if (exposed_trimmed == "DedicatedWorker"sv)
+        return ExposedTo::DedicatedWorker;
+    if (exposed_trimmed == "SharedWorker"sv)
+        return ExposedTo::SharedWorker;
+    if (exposed_trimmed == "ServiceWorker"sv)
+        return ExposedTo::ServiceWorker;
+    if (exposed_trimmed == "AudioWorklet"sv)
+        return ExposedTo::AudioWorklet;
+    if (exposed_trimmed == "Worklet"sv)
+        return ExposedTo::Worklet;
+    if (exposed_trimmed == "ShadowRealm"sv)
+        return ExposedTo::ShadowRealm;
+
+    if (exposed_trimmed[0] == '(') {
+        ExposedTo whom = Nobody;
+        for (StringView candidate : exposed_trimmed.substring_view(1, exposed_trimmed.length() - 1).split_view(',')) {
+            candidate = candidate.trim_whitespace();
+            if (candidate == "Window"sv) {
+                whom |= ExposedTo::Window;
+            } else if (candidate == "Worker"sv) {
+                whom |= ExposedTo::AllWorkers;
+            } else if (candidate == "DedicatedWorker"sv) {
+                whom |= ExposedTo::DedicatedWorker;
+            } else if (candidate == "SharedWorker"sv) {
+                whom |= ExposedTo::SharedWorker;
+            } else if (candidate == "ServiceWorker"sv) {
+                whom |= ExposedTo::ServiceWorker;
+            } else if (candidate == "AudioWorklet"sv) {
+                whom |= ExposedTo::AudioWorklet;
+            } else if (candidate == "Worklet"sv) {
+                whom |= ExposedTo::Worklet;
+            } else if (candidate == "ShadowRealm"sv) {
+                whom |= ExposedTo::ShadowRealm;
+            } else {
+                s_error_string = ByteString::formatted("Unknown Exposed attribute candidate {} in {} in {}", candidate, exposed_trimmed, interface_name);
+                return Error::from_string_view(s_error_string.view());
+            }
+        }
+        if (whom == ExposedTo::Nobody) {
+            s_error_string = ByteString::formatted("Unknown Exposed attribute {} in {}", exposed_trimmed, interface_name);
+            return Error::from_string_view(s_error_string.view());
+        }
+        return whom;
+    }
+
+    s_error_string = ByteString::formatted("Unknown Exposed attribute {} in {}", exposed_trimmed, interface_name);
+    return Error::from_string_view(s_error_string.view());
+}
+
+}