LibWeb: Added simple parsing for (at)import rules

For now, the parsing is very crude, and parses only the document url.
The meta queries for the import are ignored.

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -9,6 +9,7 @@ set(SOURCES
     Bindings/ScriptExecutionContext.cpp
     Bindings/WindowObject.cpp
     Bindings/Wrappable.cpp
+    CSS/CSSImportRule.cpp
     CSS/CSSRule.cpp
     CSS/DefaultStyleSheetSource.cpp
     CSS/Length.cpp

Userland/Libraries/LibWeb/CSS/CSSImportRule.cpp

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2021, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/URL.h>
+#include <LibWeb/CSS/CSSImportRule.h>
+#include <LibWeb/CSS/StyleSheet.h>
+
+namespace Web::CSS {
+
+CSSImportRule::CSSImportRule(URL url)
+    : m_url(move(url))
+{
+}
+
+CSSImportRule::~CSSImportRule()
+{
+}
+
+}

Userland/Libraries/LibWeb/CSS/CSSImportRule.h

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2021, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/URL.h>
+#include <LibWeb/CSS/CSSRule.h>
+
+namespace Web::CSS {
+
+class CSSImportRule : public CSSRule {
+    AK_MAKE_NONCOPYABLE(CSSImportRule);
+    AK_MAKE_NONMOVABLE(CSSImportRule);
+
+public:
+    static NonnullRefPtr<CSSImportRule> create(URL url)
+    {
+        return adopt(*new CSSImportRule(move(url)));
+    }
+
+    ~CSSImportRule();
+
+    const URL& url() const { return m_url; }
+
+    virtual StringView class_name() const { return "CSSImportRule"; };
+    virtual Type type() const { return Type::Import; };
+
+private:
+    CSSImportRule(URL);
+
+    URL m_url;
+};
+
+}

Userland/Libraries/LibWeb/CSS/Parser/CSSParser.cpp

@@ -25,6 +25,7 @@
  */
 
 #include <AK/HashMap.h>
+#include <LibWeb/CSS/CSSImportRule.h>
 #include <LibWeb/CSS/CSSRule.h>
 #include <LibWeb/CSS/Parser/CSSParser.h>
 #include <LibWeb/CSS/PropertyID.h>
@@ -70,6 +71,11 @@ bool ParsingContext::in_quirks_mode() const
     return m_document ? m_document->in_quirks_mode() : false;
 }
 
+URL ParsingContext::complete_url(const String& addr) const
+{
+    return m_document ? m_document->url().complete_url(addr) : URL::create_with_url_or_path(addr);
+}
+
 }
 
 static Optional<Color> parse_css_color(const CSS::ParsingContext&, const StringView& view)
@@ -664,6 +670,11 @@ public:
         return ch && ch != '!' && ch != ';' && ch != '}';
     }
 
+    bool is_valid_string_quotes_char(char ch) const
+    {
+        return ch == '\'' || ch == '\"';
+    }
+
     struct ValueAndImportant {
         String value;
         bool important { false };
@@ -785,31 +796,8 @@ public:
         }
     }
 
-    void parse_rule()
+    void parse_style_rule()
     {
-        consume_whitespace_or_comments();
-        if (!peek())
-            return;
-
-        // FIXME: We ignore @-rules for now.
-        if (peek() == '@') {
-            while (peek() != '{')
-                consume_one();
-            int level = 0;
-            for (;;) {
-                auto ch = consume_one();
-                if (ch == '{') {
-                    ++level;
-                } else if (ch == '}') {
-                    --level;
-                    if (level == 0)
-                        break;
-                }
-            }
-            consume_whitespace_or_comments();
-            return;
-        }
-
         parse_selector_list();
         if (!consume_specific('{')) {
             PARSE_ERROR();
@@ -820,7 +808,129 @@ public:
             PARSE_ERROR();
             return;
         }
+
         rules.append(CSS::StyleRule::create(move(current_rule.selectors), CSS::StyleDeclaration::create(move(current_rule.properties))));
+    }
+
+    Optional<String> parse_string()
+    {
+        if (!is_valid_string_quotes_char(peek())) {
+            PARSE_ERROR();
+            return {};
+        }
+
+        char end_char = consume_one();
+        buffer.clear();
+        while (peek() && peek() != end_char) {
+            if (peek() == '\\') {
+                consume_specific('\\');
+                if (peek() == 0)
+                    break;
+            }
+            buffer.append(consume_one());
+        }
+
+        String string_value(String::copy(buffer));
+        buffer.clear();
+
+        if (consume_specific(end_char)) {
+            return { string_value };
+        }
+        return {};
+    }
+
+    Optional<String> parse_url()
+    {
+        if (is_valid_string_quotes_char(peek()))
+            return parse_string();
+
+        buffer.clear();
+        while (peek() && peek() != ')')
+            buffer.append(consume_one());
+
+        String url_value(String::copy(buffer));
+        buffer.clear();
+
+        if (peek() == ')')
+            return { url_value };
+        return {};
+    }
+
+    void parse_at_import_rule()
+    {
+        consume_whitespace_or_comments();
+        Optional<String> imported_address;
+        if (is_valid_string_quotes_char(peek())) {
+            imported_address = parse_string();
+        } else if (next_is("url")) {
+            consume_specific('u');
+            consume_specific('r');
+            consume_specific('l');
+
+            consume_whitespace_or_comments();
+
+            if (!consume_specific('('))
+                return;
+            imported_address = parse_url();
+            if (!consume_specific(')'))
+                return;
+        } else {
+            PARSE_ERROR();
+            return;
+        }
+
+        if (imported_address.has_value())
+            rules.append(CSS::CSSImportRule::create(m_context.complete_url(imported_address.value())));
+
+        // FIXME: We ignore possilbe media query list
+        while (peek() && peek() != ';')
+            consume_one();
+
+        consume_specific(';');
+    }
+
+    void parse_at_rule()
+    {
+        HashMap<String, void (CSSParser::*)()> at_rules_parsers({ { "@import", &CSSParser::parse_at_import_rule } });
+
+        for (const auto& rule_parser_pair : at_rules_parsers) {
+            if (next_is(rule_parser_pair.key.characters())) {
+                for (char c : rule_parser_pair.key) {
+                    consume_specific(c);
+                }
+                (this->*(rule_parser_pair.value))();
+                return;
+            }
+        }
+
+        // FIXME: We ignore other @-rules completely for now.
+        while (peek() != 0 && peek() != '{')
+            consume_one();
+        int level = 0;
+        for (;;) {
+            auto ch = consume_one();
+            if (ch == '{') {
+                ++level;
+            } else if (ch == '}') {
+                --level;
+                if (level == 0)
+                    break;
+            }
+        }
+    }
+
+    void parse_rule()
+    {
+        consume_whitespace_or_comments();
+        if (!peek())
+            return;
+
+        if (peek() == '@') {
+            parse_at_rule();
+        } else {
+            parse_style_rule();
+        }
+
         consume_whitespace_or_comments();
     }
 

Userland/Libraries/LibWeb/CSS/Parser/CSSParser.h

@@ -27,6 +27,7 @@
 #pragma once
 
 #include <AK/NonnullRefPtr.h>
+#include <AK/String.h>
 #include <LibWeb/CSS/StyleSheet.h>
 
 namespace Web::CSS {
@@ -38,6 +39,8 @@ public:
 
     bool in_quirks_mode() const;
 
+    URL complete_url(const String&) const;
+
 private:
     const DOM::Document* m_document { nullptr };
 };

Userland/Libraries/LibWeb/Dump.cpp

@@ -28,6 +28,7 @@
 #include <AK/QuickSort.h>
 #include <AK/StringBuilder.h>
 #include <AK/Utf8View.h>
+#include <LibWeb/CSS/CSSImportRule.h>
 #include <LibWeb/CSS/CSSRule.h>
 #include <LibWeb/CSS/PropertyID.h>
 #include <LibWeb/CSS/StyleRule.h>
@@ -406,11 +407,19 @@ void dump_rule(StringBuilder& builder, const CSS::CSSRule& rule)
     case CSS::CSSRule::Type::Style:
         dump_style_rule(builder, downcast<const CSS::StyleRule>(rule));
         break;
+    case CSS::CSSRule::Type::Import:
+        dump_import_rule(builder, downcast<const CSS::CSSImportRule>(rule));
+        break;
     default:
         VERIFY_NOT_REACHED();
     }
 }
 
+void dump_import_rule(StringBuilder& builder, const CSS::CSSImportRule& rule)
+{
+    builder.appendff("  Document URL: {}\n", rule.url());
+}
+
 void dump_style_rule(StringBuilder& builder, const CSS::StyleRule& rule)
 {
     for (auto& selector : rule.selectors()) {

Userland/Libraries/LibWeb/Dump.h

@@ -41,6 +41,7 @@ void dump_sheet(const CSS::StyleSheet&);
 void dump_rule(StringBuilder&, const CSS::CSSRule&);
 void dump_rule(const CSS::CSSRule&);
 void dump_style_rule(StringBuilder&, const CSS::StyleRule&);
+void dump_import_rule(StringBuilder&, const CSS::CSSImportRule&);
 void dump_selector(StringBuilder&, const CSS::Selector&);
 void dump_selector(const CSS::Selector&);
 

Userland/Libraries/LibWeb/Forward.h

@@ -29,6 +29,7 @@
 
 namespace Web::CSS {
 class CSSRule;
+class CSSImportRule;
 class Length;
 class Selector;
 class StyleDeclaration;