test_driver.py: Add method to build the test driver tree

Signed-off-by: Ronald Cron <ronald.cron@arm.com>

Author: ronald-cron-arm

scripts/mbedtls_framework/test_driver.py

@@ -6,8 +6,12 @@
 #
 
 import argparse
+import re
+import shutil
 
+from fnmatch import fnmatch
 from pathlib import Path
+from typing import Iterable, Match, Optional, Set
 
 def get_parsearg_base() -> argparse.ArgumentParser:
     """ Get base arguments for scripts building a TF-PSA-Crypto test driver """
@@ -23,10 +27,111 @@ def get_parsearg_base() -> argparse.ArgumentParser:
                         help="Test driver name (default: %(default)s).")
     return parser
 
+def iter_code_files(root: Path) -> Iterable[Path]:
+    """
+    Iterate over all "*.c" and "*.h" files found recursively under the `include`
+    and `src` subdirectories of `root`.
+    """
+    for directory in ("include", "src"):
+        directory_path = root / directory
+        for ext in (".c", ".h"):
+            yield from directory_path.rglob(f"*{ext}")
+
 class TestDriverGenerator:
     """A TF-PSA-Crypto test driver generator"""
     def __init__(self, dst_dir: Path, driver: str):
         self.dst_dir = dst_dir
         self.driver = driver
         # Path of 'dst_dir'/include/'driver'
         self.test_driver_include_dir = None #type: Path | None
+
+    def build_tree(self, src_dir: Path, exclude_files: Optional[Set[str]] = None) -> None:
+        """
+        Build a test driver tree from `src_dir`.
+
+        The source directory `src_dir` is expected to have the following structure:
+        - an `include` directory
+        - an `src` directory
+        - the `include` directory contains exactly one subdirectory
+
+        Only the `include` and `src` directories from `src_dir` are used to build
+        the test driver tree, and their directory structure is preserved.
+
+        Only "*.h" and "*.c" files are copied. Files whose names match any of the
+        patterns in `exclude_files` are excluded.
+
+        The subdirectory inside `include` is renamed to `driver` in the test driver
+        tree, and header inclusions are adjusted accordingly.
+        """
+        include = src_dir / "include"
+        if not include.is_dir():
+            raise RuntimeError(f'Do not find "include" directory in {src_dir}')
+
+        src = src_dir / "src"
+        if not src.is_dir():
+            raise RuntimeError(f'Do not find "src" directory in {src_dir}')
+
+        entries = list(include.iterdir())
+        if len(entries) != 1 or not entries[0].is_dir():
+            raise RuntimeError(f"Found more than one directory in {include}")
+
+        src_include_dir_name = entries[0].name
+
+        if (self.dst_dir / "include").exists():
+            shutil.rmtree(self.dst_dir / "include")
+
+        if (self.dst_dir / "src").exists():
+            shutil.rmtree(self.dst_dir / "src")
+
+        if exclude_files is None:
+            exclude_files = set()
+
+        for file in iter_code_files(src_dir):
+            if any(fnmatch(file.name, pattern) for pattern in exclude_files):
+                continue
+            dst = self.dst_dir / file.relative_to(src_dir)
+            dst.parent.mkdir(parents=True, exist_ok=True)
+            shutil.copy2(file, dst)
+
+        self.test_driver_include_dir = self.dst_dir / "include" / self.driver
+        (self.dst_dir / "include" / src_include_dir_name).rename( \
+             self.test_driver_include_dir)
+
+        headers = {
+            f.relative_to(self.test_driver_include_dir).as_posix() \
+            for f in self.test_driver_include_dir.rglob("*.h")
+        }
+        for f in iter_code_files(self.dst_dir):
+            self.__rewrite_inclusions_in_file(f, headers, \
+                                              src_include_dir_name, self.driver)
+
+    @staticmethod
+    def __rewrite_inclusions_in_file(file: Path, headers: Set[str],
+                                     src_include_dir: str, driver: str,) -> None:
+        """
+        Rewrite `#include` directives in `file` that refer to `src_include_dir/...`
+        so that they instead refer to `driver/...`.
+
+        For example:
+            #include "mbedtls/private/aes.h"
+        becomes:
+            #include "libtestdriver1/private/aes.h"
+        """
+        include_line_re = re.compile(
+            fr'^\s*#\s*include\s*([<"])\s*{src_include_dir}/([^>"]+)\s*([>"])',
+            re.MULTILINE
+        )
+        text = file.read_text(encoding="utf-8")
+        changed = False
+
+        def repl(m: Match) -> str:
+            nonlocal changed
+            header = m.group(2)
+            if header in headers:
+                changed = True
+                return f'#include {m.group(1)}{driver}/{header}{m.group(3)}'
+            return m.group(0)
+
+        new_text = include_line_re.sub(repl, text)
+        if changed:
+            file.write_text(new_text, encoding="utf-8")