Support C++17 nested namespaces

include/cppast/cpp_namespace.hpp

@@ -23,9 +23,9 @@ namespace cppast
         class builder
         {
         public:
-            /// \effects Sets the namespace name and whether it is inline.
+            /// \effects Sets the namespace name and whether it is inline and nested.
-            explicit builder(std::string name, bool is_inline)
+            explicit builder(std::string name, bool is_inline, bool is_nested)
-            : namespace_(new cpp_namespace(std::move(name), is_inline))
+            : namespace_(new cpp_namespace(std::move(name), is_inline, is_nested))
             {
             }
 
@@ -60,6 +60,12 @@ namespace cppast
             return inline_;
         }
 
+        /// \returns Whether or not the namespace is part of a C++17 nested namespace.
+        bool is_nested() const noexcept
+        {
+            return nested_;
+        }
+
         /// \returns Whether or not the namespace is anonymous.
         bool is_anonymous() const noexcept
         {
@@ -67,8 +73,8 @@ namespace cppast
         }
 
     private:
-        cpp_namespace(std::string name, bool is_inline)
+        cpp_namespace(std::string name, bool is_inline, bool is_nested)
-        : cpp_entity(std::move(name)), inline_(is_inline)
+        : cpp_entity(std::move(name)), inline_(is_inline), nested_(is_nested)
         {
         }
 
@@ -80,6 +86,7 @@ namespace cppast
         }
 
         bool inline_;
+        bool nested_;
     };
 
     /// \exclude
@@ -184,9 +191,7 @@ namespace cppast
         }
 
     private:
-        cpp_using_declaration(cpp_entity_ref target) : cpp_entity(""), target_(std::move(target))
+        cpp_using_declaration(cpp_entity_ref target) : cpp_entity(""), target_(std::move(target)) {}
-        {
-        }
 
         cpp_entity_kind do_get_entity_kind() const noexcept override;
 

src/libclang/class_parser.cpp

@@ -167,7 +167,7 @@ std::unique_ptr<cpp_entity> detail::parse_cpp_class(const detail::parse_context&
                        == CXCursor_UnexposedAttr) // I have no idea what this is, but happens on Windows
                 // other children due to templates and stuff
                 return;
-            else if (auto entity = parse_entity(context, child))
+            else if (auto entity = parse_entity(context, &builder.get(), child))
                 builder.add_child(std::move(entity));
         });
     }

src/libclang/friend_parser.cpp

@@ -54,7 +54,7 @@ std::unique_ptr<cpp_entity> detail::parse_cpp_friend(const detail::parse_context
                 // for some reason libclang gives a type ref here
                 // we actually need a class decl cursor, so parse the referenced one
                 // this might be a definition, so give friend information to the parser
-                entity  = parse_entity(context, referenced, cur);
+                entity  = parse_entity(context, nullptr, referenced, cur);
                 comment = type_safe::copy(entity->comment()).value_or("");
             }
         }
@@ -74,7 +74,7 @@ std::unique_ptr<cpp_entity> detail::parse_cpp_friend(const detail::parse_context
         }
         else if (clang_isDeclaration(kind))
         {
-            entity = parse_entity(context, child, cur);
+            entity = parse_entity(context, nullptr, child, cur);
             if (entity)
             {
                 // steal comment

src/libclang/language_linkage_parser.cpp

@@ -30,7 +30,7 @@ std::unique_ptr<cpp_entity> detail::try_parse_cpp_language_linkage(const parse_c
     auto builder = cpp_language_linkage::builder(name.c_str());
     context.comments.match(builder.get(), cur);
     detail::visit_children(cur, [&](const CXCursor& child) {
-        auto entity = parse_entity(context, child);
+        auto entity = parse_entity(context, &builder.get(), child);
         if (entity)
             builder.add_child(std::move(entity));
     });

src/libclang/libclang_parser.cpp

@@ -504,7 +504,7 @@ std::unique_ptr<cpp_file> libclang_parser::do_parse(const cpp_entity_index& idx,
                  macro_iter != preprocessed.macros.end() && macro_iter->line <= line; ++macro_iter)
                 builder.add_child(std::move(macro_iter->macro));
 
-            auto entity = detail::parse_entity(context, cur);
+            auto entity = detail::parse_entity(context, &builder.get(), cur);
             if (entity)
                 builder.add_child(std::move(entity));
         }

src/libclang/namespace_parser.cpp

@@ -18,42 +18,63 @@ namespace
     {
         detail::cxtokenizer    tokenizer(context.tu, context.file, cur);
         detail::cxtoken_stream stream(tokenizer, cur);
-        // [inline] namespace [<attribute>] <identifier> {
+        // [inline] namespace|:: [<attribute>] <identifier> [{]
 
         auto is_inline = false;
         if (skip_if(stream, "inline"))
             is_inline = true;
 
-        skip(stream, "namespace");
+        // C++17 nested namespace declarations get one cursor per nested name.
+        // The first cursor starts with the `namespace` keyword, and the
+        // following start with the `::` separator. Either way, it is skipped.
+        auto is_nested = false;
+        if (!detail::skip_if(stream, "namespace"))
+        {
+            is_nested = true;
+            skip(stream, "::");
+        }
+
         auto attributes = parse_attributes(stream);
 
         // <identifier> {
         // or when anonymous: {
         if (detail::skip_if(stream, "{"))
-            return cpp_namespace::builder("", is_inline);
+            return cpp_namespace::builder("", is_inline, false);
 
         auto& name = stream.get().value();
 
         auto other_attributes = parse_attributes(stream);
         attributes.insert(attributes.end(), other_attributes.begin(), other_attributes.end());
 
+        // If the next token is not `::`, there are no more nested namespace
+        // names, and we expect to see an opening brace.
+        if (!detail::skip_if(stream, "::"))
             skip(stream, "{");
 
-        auto result = cpp_namespace::builder(name.c_str(), is_inline);
+        auto result = cpp_namespace::builder(name.c_str(), is_inline, is_nested);
         result.get().add_attribute(attributes);
         return result;
     }
 }
 
 std::unique_ptr<cpp_entity> detail::parse_cpp_namespace(const detail::parse_context& context,
-                                                        const CXCursor&              cur)
+                                                        cpp_entity& parent, const CXCursor& cur)
 {
     DEBUG_ASSERT(cur.kind == CXCursor_Namespace, detail::assert_handler{});
 
     auto builder = make_ns_builder(context, cur);
+    if (builder.get().is_nested())
+    {
+        // steal comment from parent
+        DEBUG_ASSERT(parent.kind() == cpp_namespace::kind(), detail::assert_handler{});
+        builder.get().set_comment(type_safe::copy(parent.comment()));
+        parent.set_comment(type_safe::nullopt);
+    }
+    else
         context.comments.match(builder.get(), cur);
+
     detail::visit_children(cur, [&](const CXCursor& cur) {
-        auto entity = parse_entity(context, cur);
+        auto entity = parse_entity(context, &builder.get(), cur);
         if (entity)
             builder.add_child(std::move(entity));
     });

src/libclang/parse_functions.cpp

@@ -112,7 +112,7 @@ namespace
 }
 
 std::unique_ptr<cpp_entity> detail::parse_entity(const detail::parse_context& context,
-                                                 const CXCursor&              cur,
+                                                 cpp_entity* parent, const CXCursor& cur,
                                                  const CXCursor& parent_cur) try
 {
     if (context.logger->is_verbose())
@@ -138,7 +138,8 @@ std::unique_ptr<cpp_entity> detail::parse_entity(const detail::parse_context& co
         break;
 
     case CXCursor_Namespace:
-        return parse_cpp_namespace(context, cur);
+        DEBUG_ASSERT(parent, detail::assert_handler{});
+        return parse_cpp_namespace(context, *parent, cur);
     case CXCursor_NamespaceAlias:
         return parse_cpp_namespace_alias(context, cur);
     case CXCursor_UsingDirective:

src/libclang/parse_functions.hpp

@@ -112,7 +112,7 @@ namespace cppast
             const parse_context& context, const CXCursor& cur);
 
         std::unique_ptr<cpp_entity> parse_cpp_namespace(const parse_context& context,
-                                                        const CXCursor&      cur);
+                                                        cpp_entity& parent, const CXCursor& cur);
         std::unique_ptr<cpp_entity> parse_cpp_namespace_alias(const parse_context& context,
                                                               const CXCursor&      cur);
         std::unique_ptr<cpp_entity> parse_cpp_using_directive(const parse_context& context,
@@ -162,9 +162,10 @@ namespace cppast
         std::unique_ptr<cpp_entity> parse_cpp_static_assert(const parse_context& context,
                                                             const CXCursor&      cur);
 
+        // parent: used for nested namespace, doesn't matter otherwise
         // parent_cur: used when parsing templates or friends
         std::unique_ptr<cpp_entity> parse_entity(
-            const parse_context& context, const CXCursor& cur,
+            const parse_context& context, cpp_entity* parent, const CXCursor& cur,
             const CXCursor& parent_cur = clang_getNullCursor());
     }
 } // namespace cppast::detail

src/libclang/template_parser.cpp

@@ -35,7 +35,7 @@ namespace
         DEBUG_ASSERT(!clang_Cursor_isNull(result), detail::parse_error_handler{}, cur,
                      "missing child of template");
 
-        auto entity = detail::parse_entity(context, result, cur);
+        auto entity = detail::parse_entity(context, nullptr, result, cur);
         if (!entity)
             return type_safe::nullopt;
         DEBUG_ASSERT(p(entity->kind()), detail::parse_error_handler{}, cur,

test/cpp_namespace.cpp

@@ -33,6 +33,10 @@ namespace c
 /// namespace {
 /// }
 namespace {}
+
+/// namespace f{
+/// }
+namespace e::f {}
 )";
 
     auto file  = parse({}, "cpp_namespace.cpp", code);
@@ -69,10 +73,26 @@ namespace {}
             REQUIRE(!ns.is_inline());
             REQUIRE(no_children == 0u);
         }
+        else if (ns.name() == "e")
+        {
+            REQUIRE(!ns.is_anonymous());
+            REQUIRE(!ns.is_inline());
+            REQUIRE(no_children == 1u);
+            return false; // don't have a comment
+        }
+        else if (ns.name() == "f")
+        {
+            REQUIRE(!ns.is_anonymous());
+            check_parent(ns, "e", "e::f");
+            REQUIRE(!ns.is_inline());
+            REQUIRE(no_children == 0u);
+        }
         else
             REQUIRE(false);
+
+        return true;
     });
-    REQUIRE(count == 5u);
+    REQUIRE(count == 7u);
 }
 
 TEST_CASE("cpp_namespace_alias")