windows: annotate license metadata

Like we did for Linux and macOS, we add licenses metadata to the
PYTHON.json for Windows builds.

This required a bit more effort because some libraries are built into
the extension itself and there's no easy way to automatically associate
libraries with extensions since it is all baked into Visual Studio
Project files.

Author: indygreg

cpython-windows/build.py

@@ -79,6 +79,18 @@
     'faulthandler',
 }
 
+# Used to annotate licenses.
+EXTENSION_TO_LIBRARY_DOWNLOADS_ENTRY = {
+    '_bz2': 'bzip2',
+    '_ctypes': 'libffi',
+    '_hashlib': 'openssl',
+    '_lzma': 'xz',
+    '_sqlite3': 'sqlite',
+    '_ssl': 'openssl',
+    '_uuid': 'uuid',
+    'zlib': 'zlib',
+}
+
 
 def log(msg):
     if isinstance(msg, bytes):
@@ -1204,6 +1216,16 @@ def find_additional_dependencies(project: pathlib.Path):
                 'path_static': 'build/lib/%s.lib' % lib
             })
 
+        if ext in EXTENSION_TO_LIBRARY_DOWNLOADS_ENTRY:
+            download_entry = DOWNLOADS[EXTENSION_TO_LIBRARY_DOWNLOADS_ENTRY[ext]]
+
+            # This will raise if no license metadata defined. This is
+            # intentional because EXTENSION_TO_LIBRARY_DOWNLOADS_ENTRY is
+            # manually curated and we want to fail fast.
+            entry['licenses'] = download_entry['licenses']
+            entry['license_paths'] = ['licenses/%s' % download_entry['license_file']]
+            entry['license_public_domain'] = download_entry.get('license_public_domain')
+
         res['extensions'][ext] = [entry]
 
         # Copy the extension static library.
@@ -1363,9 +1385,15 @@ def build_cpython(pgo=False):
             log('copying %s to %s' % (source, dest))
             shutil.copyfile(source, dest)
 
+        licenses_dir = out_dir / 'python' / 'licenses'
+        licenses_dir.mkdir()
+        for f in sorted(os.listdir(ROOT)):
+            if f.startswith('LICENSE.') and f.endswith('.txt'):
+                shutil.copyfile(ROOT / f, licenses_dir / f)
+
         # Create PYTHON.json file describing this distribution.
         python_info = {
-            'version': '1',
+            'version': '2',
             'os': 'windows',
             'arch': 'x86_64',
             'python_flavor': 'cpython',
@@ -1374,14 +1402,13 @@ def build_cpython(pgo=False):
             'python_include': 'install/include',
             'python_stdlib': 'install/Lib',
             'build_info': build_info,
+            'licenses': DOWNLOADS['cpython-3.7']['licenses'],
+            'license_path': 'licenses/LICENSE.cpython.txt',
         }
 
         with (out_dir / 'python' / 'PYTHON.json').open('w', encoding='utf8') as fh:
             json.dump(python_info, fh, sort_keys=True, indent=4)
 
-        # Copy software licenses file.
-        shutil.copyfile(ROOT / 'python-licenses.rst', out_dir / 'python' / 'LICENSE.rst')
-
         dest_path = BUILD / 'cpython-windows.tar'
 
         with dest_path.open('wb') as fh: