Add passthru_all_includes as a param to make_pcpp_preprocessor()

cxxheaderparser/preprocessor.py

@@ -16,11 +16,14 @@ class PreprocessorError(Exception):
 
 
 class _CustomPreprocessor(Preprocessor):
-    def __init__(self, encoding: typing.Optional[str]):
+    def __init__(
+        self, encoding: typing.Optional[str], passthru_all_includes: bool = False
+    ):
         Preprocessor.__init__(self)
         self.errors: typing.List[str] = []
         self.assume_encoding = encoding
-        self.passthru_includes = re.compile(r".")
+        if passthru_all_includes:
+            self.passthru_includes = re.compile(r".")
 
     def on_error(self, file, line, msg):
         self.errors.append(f"{file}:{line} error: {msg}")
@@ -58,12 +61,14 @@ def make_pcpp_preprocessor(
     defines: typing.List[str] = [],
     include_paths: typing.List[str] = [],
     retain_all_content: bool = False,
+    passthru_all_includes: bool = False,
     encoding: typing.Optional[str] = None,
 ) -> PreprocessorFunction:
     """
     Creates a preprocessor function that uses pcpp (which must be installed
     separately) to preprocess the input text.
 
+    :param passthru_all_includes: If set to `True`, the preprocessor will not expand any #include
     :param encoding: If specified any include files are opened with this encoding
 
     .. code-block:: python
@@ -76,7 +81,7 @@ def make_pcpp_preprocessor(
     """
 
     def _preprocess_file(filename: str, content: str) -> str:
-        pp = _CustomPreprocessor(encoding)
+        pp = _CustomPreprocessor(encoding, passthru_all_includes)
         if include_paths:
             for p in include_paths:
                 pp.add_path(p)

tests/test_preprocessor.py

@@ -69,8 +69,7 @@ def test_preprocessor_omit_content(tmp_path: pathlib.Path) -> None:
                     value=Value(tokens=[Token(value="2")]),
                 )
             ]
-        ),
-        includes=[Include(filename='"t2.h"')],
+        )
     )
 
 
@@ -110,8 +109,7 @@ def test_preprocessor_omit_content2(tmp_path: pathlib.Path) -> None:
                     value=Value(tokens=[Token(value="2")]),
                 )
             ]
-        ),
-        includes=[Include(filename='"t2.h"')],
+        )
     )
 
 
@@ -141,6 +139,25 @@ def test_preprocessor_encoding(tmp_path: pathlib.Path) -> None:
                     value=Value(tokens=[Token(value="3")]),
                 )
             ]
-        ),
-        includes=[Include(filename='"t2.h"')],
+        )
+    )
+
+
+def test_preprocessor_passthru_all_includes(tmp_path: pathlib.Path) -> None:
+    """Ensure that all #include pass through"""
+    h_content = '#include "t2.h"\n'
+
+    with open(tmp_path / "t1.h", "w") as fp:
+        fp.write(h_content)
+
+    with open(tmp_path / "t2.h", "w") as fp:
+        fp.write("")
+
+    options = ParserOptions(
+        preprocessor=make_pcpp_preprocessor(passthru_all_includes=True)
+    )
+    data = parse_file(tmp_path / "t1.h", options=options)
+
+    assert data == ParsedData(
+        namespace=NamespaceScope(), includes=[Include(filename='"t2.h"')]
     )