Tools: add OUTPUT_DIR option to the "check_cppcheck" target

- Add optional `--build-dir` & `--output-dir` arguments to
  "static_check_cppcheck.py".
- Support using `project_source_info.py` without the CWD having
  to be the build-directory.
- Make the script executable.

GNUmakefile

@@ -56,7 +56,12 @@ Testing Targets
 Static Source Code Checking
    Not associated with building Blender.
 
-   * check_cppcheck:        Run blender source through cppcheck (C & C++).
+   * check_cppcheck:
+     Run blender source through cppcheck (C & C++).
+
+     To write log files into a user defined location append 'OUTPUT_DIR',
+     e.g. 'OUTPUT_DIR=/example/path'
+
    * check_clang_array:     Run blender source through clang array checking script (C & C++).
    * check_struct_comments: Check struct member comments are correct (C & C++).
    * check_deprecated:      Check if there is any deprecated code to remove.
@@ -474,9 +479,10 @@ project_eclipse: .FORCE
 
 check_cppcheck: .FORCE
 	@$(CMAKE_CONFIG)
-	@cd "$(BUILD_DIR)" ; \
 	$(PYTHON) \
-	    "$(BLENDER_DIR)/tools/check_source/static_check_cppcheck.py"
+	    "$(BLENDER_DIR)/tools/check_source/static_check_cppcheck.py" \
+	    --build-dir=$(BUILD_DIR) \
+	    --output-dir=$(OUTPUT_DIR)
 
 check_struct_comments: .FORCE
 	@$(CMAKE_CONFIG)

tools/check_source/project_source_info.py

@@ -4,8 +4,10 @@
 
 
 __all__ = (
+    "cmake_dir_set",
     "build_info",
     "SOURCE_DIR",
+    "CMAKE_DIR",
 )
 
 
@@ -38,6 +40,19 @@ SOURCE_DIR = join(dirname(__file__), "..", "..")
 SOURCE_DIR = normpath(SOURCE_DIR)
 SOURCE_DIR = abspath(SOURCE_DIR)
 
+# copied from project_info.py
+CMAKE_DIR = "."
+
+
+def cmake_dir_set(cmake_dir: str) -> None:
+    """
+    Callers may not run this tool from the CWD, in this case,
+    allow the value to be set.
+    """
+    # Use a method in case any other values need to be updated in the future.
+    global CMAKE_DIR
+    CMAKE_DIR = cmake_dir
+
 
 def is_c_header(filename: str) -> bool:
     ext = os.path.splitext(filename)[1]
@@ -53,10 +68,6 @@ def is_c_any(filename: str) -> bool:
     return is_c(filename) or is_c_header(filename)
 
 
-# copied from project_info.py
-CMAKE_DIR = "."
-
-
 def cmake_cache_var_iter() -> Iterator[tuple[str, str, str]]:
     import re
     re_cache = re.compile(r'([A-Za-z0-9_\-]+)?:?([A-Za-z0-9_\-]+)?=(.*)$')
@@ -102,12 +113,25 @@ def makefile_log() -> list[str]:
 
     if make_exe_basename.startswith(("make", "gmake")):
         print("running 'make' with --dry-run ...")
-        process = subprocess.Popen([make_exe, "--always-make", "--dry-run", "--keep-going", "VERBOSE=1"],
+        process = subprocess.Popen(
+            (
+                make_exe,
+                "-C", CMAKE_DIR,
+                "--always-make",
+                "--dry-run",
+                "--keep-going",
+                "VERBOSE=1",
+            ),
             stdout=subprocess.PIPE,
         )
     elif make_exe_basename.startswith("ninja"):
         print("running 'ninja' with -t commands ...")
-        process = subprocess.Popen([make_exe, "-t", "commands"],
+        process = subprocess.Popen(
+            (
+                make_exe,
+                "-C", CMAKE_DIR,
+                "-t", "commands",
+            ),
             stdout=subprocess.PIPE,
         )
 

tools/check_source/static_check_cppcheck.py

@@ -3,10 +3,18 @@
 #
 # SPDX-License-Identifier: GPL-2.0-or-later
 
+"""
+Run CPPCHECK on Blender's source files,
+writing results to a log as well as a summary of all checks.
+
+Existing logs are renamed to ``.old.log`` so they can be compared.
+"""
+
 __all__ = (
     "main",
 )
 
+import argparse
 import project_source_info
 import subprocess
 import sys
@@ -352,9 +360,59 @@ def cppcheck_generate_summary(
             log_summary_fh.write(line)
 
 
+def argparse_create() -> argparse.ArgumentParser:
+
+    parser = argparse.ArgumentParser(
+        description=__doc__,
+        formatter_class=argparse.RawTextHelpFormatter,
+    )
+
+    parser.add_argument(
+        "--build-dir",
+        dest="build_dir",
+        metavar='BUILD_DIR',
+        type=str,
+        help=(
+            "The build directory (containing CMakeCache.txt).\n"
+            "\n"
+            "Defaults to the \".\"."
+        ),
+        default=".",
+        required=False,
+    )
+
+    parser.add_argument(
+        "--output-dir",
+        dest="output_dir",
+        metavar='OUTPUT_DIR',
+        type=str,
+        help=(
+            "Specify the directory where CPPCHECK logs will be written to.\n"
+            "Using this may be preferred so the build directory can be cleared\n"
+            "without loosing the result of previous checks.\n"
+            "\n"
+            "Defaults to {BUILD_DIR}/cppcheck/"
+        ),
+        default="",
+        required=False,
+    )
+
+    return parser
+
+
 def main() -> None:
-    cmake_dir = os.path.normpath(os.path.abspath(project_source_info.CMAKE_DIR))
-    cppcheck_dir = os.path.join(cmake_dir, "cppcheck")
+    args = argparse_create().parse_args()
+
+    project_source_info.cmake_dir_set(args.build_dir)
+
+    cppcheck_dir = args.output_dir
+
+    if cppcheck_dir:
+        cppcheck_dir = os.path.normpath(os.path.abspath(cppcheck_dir))
+    else:
+        cppcheck_dir = os.path.join(os.path.normpath(os.path.abspath(project_source_info.CMAKE_DIR)), "cppcheck")
+
+    del args
 
     filepath_output_log = os.path.join(cppcheck_dir, "cppcheck.part.log")
     filepath_output_summary_log = os.path.join(cppcheck_dir, "cppcheck_summary.part.log")