Tools: fixes/improvements for 'check_struct_comments' check

- Fix using forward declarations when extracting struct information as
  it causing this check to be ignored.
- Fix extracting comments which sometimes included code fragments.
- Fix extracting the outer comment for struct declarations on a single
  line.
- Skip source files in the build directory.

build_files/cmake/cmake_static_check_clang.py

@@ -164,16 +164,18 @@ class clang_checkers:
             #     IPython.embed()
 
             if node.kind == CursorKind.STRUCT_DECL:
-                struct_type = node.spelling.strip()
-                if not struct_type:
-                    # The parent may be a `typedef [..] TypeID` where `[..]` is `struct { a; b; c; }`.
-                    # Inspect the parent.
-                    if node_parent is not None and (node_parent.kind == CursorKind.TYPEDEF_DECL):
-                        tokens = list(node_parent.get_tokens())
-                        if tokens[0].spelling == "typedef":
-                            struct_type = tokens[-1].spelling
+                # Ignore forward declarations.
+                if next(node.get_children(), None) is not None:
+                    struct_type = node.spelling.strip()
+                    if not struct_type:
+                        # The parent may be a `typedef [..] TypeID` where `[..]` is `struct { a; b; c; }`.
+                        # Inspect the parent.
+                        if node_parent is not None and (node_parent.kind == CursorKind.TYPEDEF_DECL):
+                            tokens = list(node_parent.get_tokens())
+                            if tokens[0].spelling == "typedef":
+                                struct_type = tokens[-1].spelling
 
-                struct_decl_map[struct_type] = node
+                    struct_decl_map[struct_type] = node
 
             # Ignore declarations for anything defined outside this file.
             if str(node.location.file) == filepath:
@@ -238,8 +240,31 @@ class clang_checkers:
                                     break
 
                             beg = end - 1
-                            while beg != 0 and bytes((file_data[beg],)) != b"\n":
+                            while beg != 0 and bytes((file_data[beg],)) not in {
+                                    b"\n",
+                                    # Needed so declarations on a single line don't detect a comment
+                                    # from an outer comment, e.g.
+                                    #    SomeStruct x = {
+                                    #      /*list*/ {nullptr, nullptr},
+                                    #    };
+                                    # Would start inside the first `nullptr` and walk backwards to find `/*list*/`.
+                                    b"{"
+                            }:
                                 beg -= 1
+
+                            # Seek back until the comment end (in some cases this includes code).
+                            # This occurs when the body of the declaration includes code, e.g.
+                            #    rcti x = {
+                            #      /*xmin*/ foo->bar.baz,
+                            #      ... snip ...
+                            #    };
+                            # Where `"xmin*/ foo->bar."` would be extracted were it not for this check.
+                            # There might be a more elegant way to handle this, for how snipping off the last
+                            # comment characters is sufficient.
+                            end_test = file_data.rfind(b"*/", end + 1, beg)
+                            if end_test != -1:
+                                end = end_test
+
                             text = file_data[beg:end]
                             if text.lstrip().startswith(b"/*"):
                                 if not has_newline:
@@ -422,6 +447,10 @@ def source_info_filter(
                     has_match = True
             if not has_match:
                 continue
+        else:
+            # Skip files not in source (generated files from the build directory),
+            # these could be check but it's not all that useful (preview blend ... etc).
+            continue
 
         source_info_result.append(item)