windows: parse build configuration with argparse

.github/workflows/test-windows.yml

@@ -88,7 +88,7 @@ jobs:
     - name: Prepare build
       if: steps.build-cache.outputs.cache-hit != 'true'
       run: |
-        & python.exe winbuild\build_prepare.py -v --python=$env:pythonLocation --srcdir
+        & python.exe winbuild\build_prepare.py -v --python $env:pythonLocation
       shell: pwsh
 
     - name: Build dependencies / libjpeg-turbo

winbuild/build.rst

@@ -38,42 +38,50 @@ Visual Studio is found automatically with ``vswhere.exe``.
 Build configuration
 -------------------
 
-The following environment variables, if set, will override the default
-behaviour of ``build_prepare.py``:
+Run ``build_prepare.py`` to configure the build::
 
-* ``PYTHON`` + ``EXECUTABLE`` point to the target version of Python.
-  If ``PYTHON`` is unset, the version of Python used to run
-  ``build_prepare.py`` will be used. If only ``PYTHON`` is set,
-  ``EXECUTABLE`` defaults to ``python.exe``.
-* ``ARCHITECTURE`` is used to select a ``x86``, ``x64`` or ``ARM64`` build.
-  By default, uses same architecture as the version of Python used to run ``build_prepare.py``.
-* ``PILLOW_BUILD`` can be used to override the ``winbuild\build`` directory
-  path, used to store generated build scripts and compiled libraries.
-  **Warning:** This directory is wiped when ``build_prepare.py`` is run.
-* ``PILLOW_DEPS`` points to the directory used to store downloaded
-  dependencies. By default ``winbuild\depends`` is used.
+    usage: winbuild\build_prepare.py [-h] [-v] [-d PILLOW_BUILD]
+                                     [--depends PILLOW_DEPS]
+                                     [--architecture {x86,x64,ARM64}]
+                                     [--python PYTHON] [--executable EXECUTABLE]
+                                     [--nmake] [--no-imagequant] [--no-fribidi]
 
-``build_prepare.py`` also supports the following command line parameters:
+    Download dependencies and generate build scripts for Pillow.
 
-* ``-v`` will print generated scripts.
-* ``--nmake`` will use NMake instead of Ninja for CMake dependencies
-* ``--no-imagequant`` will skip GPL-licensed ``libimagequant`` optional dependency
-* ``--no-fribidi`` or ``--no-raqm`` will skip optional LGPL-licensed dependency FriBiDi
-  (required for Raqm text shaping).
-* ``--python=<path>`` and ``--executable=<exe>`` override ``PYTHON`` and ``EXECUTABLE``.
-* ``--architecture=<arch>`` overrides ``ARCHITECTURE``.
-* ``--dir=<path>`` and ``--depends=<path>`` override ``PILLOW_BUILD``
-  and ``PILLOW_DEPS``.
+    options:
+      -h, --help            show this help message and exit
+      -v, --verbose         print generated scripts
+      -d PILLOW_BUILD, --dir PILLOW_BUILD, --build-dir PILLOW_BUILD
+                            build directory (default: 'winbuild\build')
+      --depends PILLOW_DEPS
+                            directory used to store cached dependencies (default:
+                            'winbuild\depends')
+      --architecture {x86,x64,ARM64}
+                            build architecture (default: same as host python)
+      --python PYTHON       Python install directory (default: use host python)
+      --executable EXECUTABLE
+                            Python executable (default: use host python)
+      --nmake               build dependencies using NMake instead of Ninja
+      --no-imagequant       skip GPL-licensed optional dependency libimagequant
+      --no-fribidi, --no-raqm
+                            skip LGPL-licensed optional dependency FriBiDi
+
+    Arguments can also be supplied using the environment variables PILLOW_BUILD,
+    PILLOW_DEPS, ARCHITECTURE, PYTHON, EXECUTABLE. See winbuild\build.rst for more
+    information.
+
+**Warning:** The build directory is wiped when ``build_prepare.py`` is run.
 
 Dependencies
 ------------
 
 Dependencies will be automatically downloaded by ``build_prepare.py``.
 By default, downloaded dependencies are stored in ``winbuild\depends``;
-set the ``PILLOW_DEPS`` environment variable to override this location.
+use the ``--depends`` argument or ``PILLOW_DEPS`` environment variable
+to override this location.
 
 To build all dependencies, run ``winbuild\build\build_dep_all.cmd``,
-or run the individual scripts to build each dependency separately.
+or run the individual scripts in order to build each dependency separately.
 
 Building Pillow
 ---------------
@@ -106,7 +114,7 @@ The following is a simplified version of the script used on AppVeyor:
 
     set PYTHON=C:\Python38\bin
     cd /D C:\Pillow\winbuild
-    C:\Python37\bin\python.exe build_prepare.py -v --depends=C:\pillow-depends
+    C:\Python37\bin\python.exe build_prepare.py -v --depends C:\pillow-depends
     build\build_dep_all.cmd
     build\build_pillow.cmd install
     cd ..

winbuild/build_prepare.py

@@ -1,3 +1,4 @@
+import argparse
 import os
 import platform
 import re
@@ -434,7 +435,7 @@ def extract_dep(url, filename):
     import urllib.request
     import zipfile
 
-    file = os.path.join(depends_dir, filename)
+    file = os.path.join(args.depends_dir, filename)
     if not os.path.exists(file):
         ex = None
         for i in range(3):
@@ -475,12 +476,12 @@ def extract_dep(url, filename):
 
 
 def write_script(name, lines):
-    name = os.path.join(build_dir, name)
+    name = os.path.join(args.build_dir, name)
     lines = [line.format(**prefs) for line in lines]
     print("Writing " + name)
     with open(name, "w", newline="") as f:
         f.write(os.linesep.join(lines))
-    if verbose:
+    if args.verbose:
         for line in lines:
             print("    " + line)
 
@@ -549,11 +550,14 @@ def build_dep(name):
 def build_dep_all():
     lines = ["@echo on"]
     for dep_name in deps:
+        print()
         if dep_name in disabled:
+            print(f"Skipping disabled dependency {dep_name}")
             continue
         script = build_dep(dep_name)
         lines.append(rf'cmd.exe /c "{{build_dir}}\{script}"')
         lines.append("if errorlevel 1 echo Build failed! && exit /B 1")
+    print()
     lines.append("@echo All Pillow dependencies built successfully!")
     write_script("build_dep_all.cmd", lines)
 
@@ -572,59 +576,90 @@ def build_pillow():
 
 
 if __name__ == "__main__":
-    # winbuild directory
     winbuild_dir = os.path.dirname(os.path.realpath(__file__))
+    pillow_dir = os.path.realpath(os.path.join(winbuild_dir, ".."))
 
-    verbose = False
-    disabled = []
-    depends_dir = os.environ.get("PILLOW_DEPS", os.path.join(winbuild_dir, "depends"))
-    python_dir = os.environ.get("PYTHON")
-    python_exe = os.environ.get("EXECUTABLE", "python.exe")
-    architecture = os.environ.get(
-        "ARCHITECTURE",
-        "ARM64"
-        if platform.machine() == "ARM64"
-        else ("x86" if struct.calcsize("P") == 4 else "x64"),
+    parser = argparse.ArgumentParser(
+        prog="winbuild\\build_prepare.py",
+        description="Download dependencies and generate build scripts for Pillow.",
+        epilog="""Arguments can also be supplied using the environment variables
+                  PILLOW_BUILD, PILLOW_DEPS, ARCHITECTURE, PYTHON, EXECUTABLE.
+                  See winbuild\\build.rst for more information.""",
     )
-    build_dir = os.environ.get("PILLOW_BUILD", os.path.join(winbuild_dir, "build"))
-    cmake_generator = "Ninja"
-    sources_dir = ""
-    for arg in sys.argv[1:]:
-        if arg == "-v":
-            verbose = True
-        elif arg == "--nmake":
-            cmake_generator = "NMake Makefiles"
-        elif arg == "--no-imagequant":
-            disabled += ["libimagequant"]
-        elif arg == "--no-raqm" or arg == "--no-fribidi":
-            disabled += ["fribidi"]
-        elif arg.startswith("--depends="):
-            depends_dir = arg[10:]
-        elif arg.startswith("--python="):
-            python_dir = arg[9:]
-        elif arg.startswith("--executable="):
-            python_exe = arg[13:]
-        elif arg.startswith("--architecture="):
-            architecture = arg[15:]
-        elif arg.startswith("--dir="):
-            build_dir = arg[6:]
-        elif arg == "--srcdir":
-            sources_dir = os.path.sep + "src"
-        else:
-            msg = "Unknown parameter: " + arg
-            raise ValueError(msg)
+    parser.add_argument(
+        "-v", "--verbose", action="store_true", help="print generated scripts"
+    )
+    parser.add_argument(
+        "-d",
+        "--dir",
+        "--build-dir",
+        dest="build_dir",
+        metavar="PILLOW_BUILD",
+        default=os.environ.get("PILLOW_BUILD", os.path.join(winbuild_dir, "build")),
+        help="build directory (default: 'winbuild\\build')",
+    )
+    parser.add_argument(
+        "--depends",
+        dest="depends_dir",
+        metavar="PILLOW_DEPS",
+        default=os.environ.get("PILLOW_DEPS", os.path.join(winbuild_dir, "depends")),
+        help="directory used to store cached dependencies (default: 'winbuild\\depends')",  # noqa: E501
+    )
+    parser.add_argument(
+        "--architecture",
+        choices=architectures,
+        default=os.environ.get(
+            "ARCHITECTURE",
+            (
+                "ARM64"
+                if platform.machine() == "ARM64"
+                else ("x86" if struct.calcsize("P") == 4 else "x64")
+            ),
+        ),
+        help="build architecture (default: same as host python)",
+    )
+    parser.add_argument(
+        "--python",
+        dest="python_dir",
+        metavar="PYTHON",
+        default=os.environ.get("PYTHON"),
+        help="Python install directory (default: use host python)",
+    )
+    parser.add_argument(
+        "--executable",
+        dest="python_exe",
+        metavar="EXECUTABLE",
+        default=os.environ.get("EXECUTABLE", "python.exe"),
+        help="Python executable (default: use host python)",
+    )
+    parser.add_argument(
+        "--nmake",
+        dest="cmake_generator",
+        action="store_const",
+        const="NMake Makefiles",
+        default="Ninja",
+        help="build dependencies using NMake instead of Ninja",
+    )
+    parser.add_argument(
+        "--no-imagequant",
+        action="store_true",
+        help="skip GPL-licensed optional dependency libimagequant",
+    )
+    parser.add_argument(
+        "--no-fribidi",
+        "--no-raqm",
+        action="store_true",
+        help="skip LGPL-licensed optional dependency FriBiDi",
+    )
+    args = parser.parse_args()
 
-    # dependency cache directory
-    os.makedirs(depends_dir, exist_ok=True)
-    print("Caching dependencies in:", depends_dir)
+    arch_prefs = architectures[args.architecture]
+    print("Target Architecture:", args.architecture)
 
-    if python_dir is None:
-        python_dir = os.path.dirname(os.path.realpath(sys.executable))
-        python_exe = os.path.basename(sys.executable)
-    print("Target Python:", os.path.join(python_dir, python_exe))
-
-    arch_prefs = architectures[architecture]
-    print("Target Architecture:", architecture)
+    if args.python_dir is None:
+        args.python_dir = os.path.dirname(os.path.realpath(sys.executable))
+        args.python_exe = os.path.basename(sys.executable)
+    print("Target Python:", os.path.join(args.python_dir, args.python_exe))
 
     msvs = find_msvs()
     if msvs is None:
@@ -632,35 +667,47 @@ if __name__ == "__main__":
         raise RuntimeError(msg)
     print("Found Visual Studio at:", msvs["vs_dir"])
 
-    print("Using output directory:", build_dir)
+    # dependency cache directory
+    args.depends_dir = os.path.abspath(args.depends_dir)
+    os.makedirs(args.depends_dir, exist_ok=True)
+    print("Caching dependencies in:", args.depends_dir)
+
+    args.build_dir = os.path.abspath(args.build_dir)
+    print("Using output directory:", args.build_dir)
 
     # build directory for *.h files
-    inc_dir = os.path.join(build_dir, "inc")
+    inc_dir = os.path.join(args.build_dir, "inc")
     # build directory for *.lib files
-    lib_dir = os.path.join(build_dir, "lib")
+    lib_dir = os.path.join(args.build_dir, "lib")
     # build directory for *.bin files
-    bin_dir = os.path.join(build_dir, "bin")
+    bin_dir = os.path.join(args.build_dir, "bin")
     # directory for storing project files
-    sources_dir = build_dir + sources_dir
+    sources_dir = os.path.join(args.build_dir, "src")
     # copy dependency licenses to this directory
-    license_dir = os.path.join(build_dir, "license")
+    license_dir = os.path.join(args.build_dir, "license")
 
-    shutil.rmtree(build_dir, ignore_errors=True)
-    os.makedirs(build_dir, exist_ok=False)
+    shutil.rmtree(args.build_dir, ignore_errors=True)
+    os.makedirs(args.build_dir, exist_ok=False)
     for path in [inc_dir, lib_dir, bin_dir, sources_dir, license_dir]:
         os.makedirs(path, exist_ok=True)
 
+    disabled = []
+    if args.no_imagequant:
+        disabled += ["libimagequant"]
+    if args.no_fribidi:
+        disabled += ["fribidi"]
+
     prefs = {
         # Python paths / preferences
-        "python_dir": python_dir,
-        "python_exe": python_exe,
-        "architecture": architecture,
+        "python_dir": args.python_dir,
+        "python_exe": args.python_exe,
+        "architecture": args.architecture,
         **arch_prefs,
         # Pillow paths
-        "pillow_dir": os.path.realpath(os.path.join(winbuild_dir, "..")),
+        "pillow_dir": pillow_dir,
         "winbuild_dir": winbuild_dir,
         # Build paths
-        "build_dir": build_dir,
+        "build_dir": args.build_dir,
         "inc_dir": inc_dir,
         "lib_dir": lib_dir,
         "bin_dir": bin_dir,
@@ -669,7 +716,7 @@ if __name__ == "__main__":
         # Compilers / Tools
         **msvs,
         "cmake": "cmake.exe",  # TODO find CMAKE automatically
-        "cmake_generator": cmake_generator,
+        "cmake_generator": args.cmake_generator,
         # TODO find NASM automatically
         # script header
         "header": sum([header, msvs["header"], ["@echo on"]], []),
@@ -682,4 +729,6 @@ if __name__ == "__main__":
 
     write_script(".gitignore", ["*"])
     build_dep_all()
+    if args.verbose:
+        print()
     build_pillow()