Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89
Commit: 93712b24bf
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256
Reviewed-by: https://github.com/sideshowbarker

Libraries/LibWeb/ReferrerPolicy/AbstractOperations.cpp

@@ -0,0 +1,234 @@
+/*
+ * Copyright (c) 2022, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2024, Jamie Mansfield <jmansfield@cadixdev.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibURL/URL.h>
+#include <LibWeb/DOM/Document.h>
+#include <LibWeb/DOMURL/DOMURL.h>
+#include <LibWeb/Fetch/Infrastructure/HTTP/Requests.h>
+#include <LibWeb/Fetch/Infrastructure/URL.h>
+#include <LibWeb/HTML/Window.h>
+#include <LibWeb/ReferrerPolicy/AbstractOperations.h>
+#include <LibWeb/ReferrerPolicy/ReferrerPolicy.h>
+#include <LibWeb/SecureContexts/AbstractOperations.h>
+
+namespace Web::ReferrerPolicy {
+
+// https://w3c.github.io/webappsec-referrer-policy/#parse-referrer-policy-from-header
+ReferrerPolicy parse_a_referrer_policy_from_a_referrer_policy_header(Fetch::Infrastructure::Response const& response)
+{
+    // 1. Let policy-tokens be the result of extracting header list values given `Referrer-Policy` and response’s header list.
+    auto policy_tokens_or_failure = Fetch::Infrastructure::extract_header_list_values("Referrer-Policy"sv.bytes(), response.header_list());
+    auto policy_tokens = policy_tokens_or_failure.has<Vector<ByteBuffer>>() ? policy_tokens_or_failure.get<Vector<ByteBuffer>>() : Vector<ByteBuffer> {};
+
+    // 2. Let policy be the empty string.
+    auto policy = ReferrerPolicy::EmptyString;
+
+    // 3. For each token in policy-tokens, if token is a referrer policy and token is not the empty string, then set policy to token.
+    for (auto token : policy_tokens) {
+        auto referrer_policy = from_string(token);
+        if (referrer_policy.has_value() && referrer_policy.value() != ReferrerPolicy::EmptyString)
+            policy = referrer_policy.release_value();
+    }
+
+    // 4. Return policy.
+    return policy;
+}
+
+// https://w3c.github.io/webappsec-referrer-policy/#set-requests-referrer-policy-on-redirect
+void set_request_referrer_policy_on_redirect(Fetch::Infrastructure::Request& request, Fetch::Infrastructure::Response const& response)
+{
+    // 1. Let policy be the result of executing § 8.1 Parse a referrer policy from a Referrer-Policy header on
+    //    actualResponse.
+    auto policy = parse_a_referrer_policy_from_a_referrer_policy_header(response);
+
+    // 2. If policy is not the empty string, then set request’s referrer policy to policy.
+    if (policy != ReferrerPolicy::EmptyString)
+        request.set_referrer_policy(policy);
+}
+
+// https://w3c.github.io/webappsec-referrer-policy/#determine-requests-referrer
+Optional<URL::URL> determine_requests_referrer(Fetch::Infrastructure::Request const& request)
+{
+    // 1. Let policy be request’s referrer policy.
+    auto const& policy = request.referrer_policy();
+
+    // 2. Let environment be request’s client.
+    auto environment = request.client();
+
+    // 3. Switch on request’s referrer:
+    auto referrer_source = request.referrer().visit(
+        // "client"
+        [&](Fetch::Infrastructure::Request::Referrer referrer) -> Optional<URL::URL> {
+            // Note: If request’s referrer is "no-referrer", Fetch will not call into this algorithm.
+            VERIFY(referrer == Fetch::Infrastructure::Request::Referrer::Client);
+
+            // FIXME: Add a const global_object() getter to ESO
+            auto& global_object = const_cast<HTML::EnvironmentSettingsObject&>(*environment).global_object();
+
+            // 1. If environment’s global object is a Window object, then
+            if (is<HTML::Window>(global_object)) {
+                // 1. Let document be the associated Document of environment’s global object.
+                auto const& document = static_cast<HTML::Window const&>(global_object).associated_document();
+
+                // 2. If document’s origin is an opaque origin, return no referrer.
+                if (document.origin().is_opaque())
+                    return {};
+
+                // FIXME: 3. While document is an iframe srcdoc document, let document be document’s browsing context’s
+                //           browsing context container’s node document.
+
+                // 4. Let referrerSource be document’s URL.
+                return document.url();
+            }
+            // 2. Otherwise, let referrerSource be environment’s creation URL.
+            else {
+                return environment->creation_url;
+            }
+        },
+        // a URL
+        [&](URL::URL const& url) -> Optional<URL::URL> {
+            // Let referrerSource be request’s referrer.
+            return url;
+        });
+    // NOTE: This only happens in step 1.2. of the "client" case above.
+    if (!referrer_source.has_value())
+        return {};
+
+    // 4. Let request’s referrerURL be the result of stripping referrerSource for use as a referrer.
+    auto referrer_url = strip_url_for_use_as_referrer(referrer_source);
+
+    // 5. Let referrerOrigin be the result of stripping referrerSource for use as a referrer, with the origin-only flag
+    //    set to true.
+    auto referrer_origin = strip_url_for_use_as_referrer(referrer_source, OriginOnly::Yes);
+
+    // 6. If the result of serializing referrerURL is a string whose length is greater than 4096, set referrerURL to
+    //    referrerOrigin.
+    if (referrer_url.has_value() && referrer_url.value().serialize().length() > 4096)
+        referrer_url = referrer_origin;
+
+    // 7. The user agent MAY alter referrerURL or referrerOrigin at this point to enforce arbitrary policy
+    //    considerations in the interests of minimizing data leakage. For example, the user agent could strip the URL
+    //    down to an origin, modify its host, replace it with an empty string, etc.
+
+    // 8. Execute the statements corresponding to the value of policy:
+    // Note: If request’s referrer policy is the empty string, Fetch will not call into this algorithm.
+    VERIFY(policy != ReferrerPolicy::EmptyString);
+    switch (policy) {
+    // "no-referrer"
+    case ReferrerPolicy::NoReferrer:
+        // Return no referrer
+        return {};
+    // "origin"
+    case ReferrerPolicy::Origin:
+        // Return referrerOrigin
+        return referrer_origin;
+    // "unsafe-url"
+    case ReferrerPolicy::UnsafeURL:
+        // Return referrerURL.
+        return referrer_url;
+    // "strict-origin"
+    case ReferrerPolicy::StrictOrigin:
+        // 1. If referrerURL is a potentially trustworthy URL and request’s current URL is not a potentially
+        //    trustworthy URL, then return no referrer.
+        if (referrer_url.has_value()
+            && SecureContexts::is_url_potentially_trustworthy(*referrer_url) == SecureContexts::Trustworthiness::PotentiallyTrustworthy
+            && SecureContexts::is_url_potentially_trustworthy(request.current_url()) == SecureContexts::Trustworthiness::NotTrustworthy) {
+            return {};
+        }
+
+        // 2. Return referrerOrigin.
+        return referrer_origin;
+    // "strict-origin-when-cross-origin"
+    case ReferrerPolicy::StrictOriginWhenCrossOrigin:
+        // 1. If the origin of referrerURL and the origin of request’s current URL are the same, then return
+        //    referrerURL.
+        if (referrer_url.has_value() && referrer_url->origin().is_same_origin(request.current_url().origin()))
+            return referrer_url;
+
+        // 2. If referrerURL is a potentially trustworthy URL and request’s current URL is not a potentially
+        //    trustworthy URL, then return no referrer.
+        if (referrer_url.has_value()
+            && SecureContexts::is_url_potentially_trustworthy(*referrer_url) == SecureContexts::Trustworthiness::PotentiallyTrustworthy
+            && SecureContexts::is_url_potentially_trustworthy(request.current_url()) == SecureContexts::Trustworthiness::NotTrustworthy) {
+            return {};
+        }
+
+        // 3. Return referrerOrigin.
+        return referrer_origin;
+    // "same-origin"
+    case ReferrerPolicy::SameOrigin:
+        // 1. If the origin of referrerURL and the origin of request’s current URL are the same, then return
+        //    referrerURL.
+        if (referrer_url.has_value()
+            && referrer_url->origin().is_same_origin(request.current_url().origin())) {
+            return referrer_url;
+        }
+
+        // 2. Return no referrer.
+        return {};
+    // "origin-when-cross-origin"
+    case ReferrerPolicy::OriginWhenCrossOrigin:
+        // 1. If the origin of referrerURL and the origin of request’s current URL are the same, then return
+        //    referrerURL.
+        if (referrer_url.has_value()
+            && referrer_url->origin().is_same_origin(request.current_url().origin())) {
+            return referrer_url;
+        }
+
+        // 2. Return referrerOrigin.
+        return referrer_origin;
+    // "no-referrer-when-downgrade"
+    case ReferrerPolicy::NoReferrerWhenDowngrade:
+        // 1. If referrerURL is a potentially trustworthy URL and request’s current URL is not a potentially
+        //    trustworthy URL, then return no referrer.
+        if (referrer_url.has_value()
+            && SecureContexts::is_url_potentially_trustworthy(*referrer_url) == SecureContexts::Trustworthiness::PotentiallyTrustworthy
+            && SecureContexts::is_url_potentially_trustworthy(request.current_url()) == SecureContexts::Trustworthiness::NotTrustworthy) {
+            return {};
+        }
+
+        // 2. Return referrerURL.
+        return referrer_url;
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
+// https://w3c.github.io/webappsec-referrer-policy/#strip-url
+Optional<URL::URL> strip_url_for_use_as_referrer(Optional<URL::URL> url, OriginOnly origin_only)
+{
+    // 1. If url is null, return no referrer.
+    if (!url.has_value())
+        return {};
+
+    // 2. If url’s scheme is a local scheme, then return no referrer.
+    if (Fetch::Infrastructure::LOCAL_SCHEMES.span().contains_slow(url->scheme()))
+        return {};
+
+    // 3. Set url’s username to the empty string.
+    url->set_username(""sv);
+
+    // 4. Set url’s password to the empty string.
+    url->set_password(""sv);
+
+    // 5. Set url’s fragment to null.
+    url->set_fragment({});
+
+    // 6. If the origin-only flag is true, then:
+    if (origin_only == OriginOnly::Yes) {
+        // 1. Set url’s path to « the empty string ».
+        url->set_paths({ ""sv });
+
+        // 2. Set url’s query to null.
+        url->set_query({});
+    }
+
+    // 7. Return url.
+    return url;
+}
+
+}