subprojects: Add Microsoft WebView2 SDK

Add WebView2 NuGet package downloader and meson file

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4631>

subprojects/webview2/.gitignore

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+webview2-*/
+webview2-*.zip

subprojects/webview2/download-binary.py

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+#!/usr/bin/env python3
+
+import os
+import sys
+import ssl
+import zipfile
+import hashlib
+import urllib.request
+import urllib.error
+
+# Disable certificate checking because it always fails on Windows
+# We verify the checksum anyway.
+ctx = ssl.create_default_context()
+ctx.check_hostname = False
+ctx.verify_mode = ssl.CERT_NONE
+
+EXTRACTDIR = 'webview2-{}'
+BASENAME = '{}.zip'.format(EXTRACTDIR)
+BASE_URL = 'https://www.nuget.org/api/v2/package/Microsoft.Web.WebView2/{}'
+
+version = sys.argv[1]
+zip_sha256 = sys.argv[2]
+source_dir = os.path.join(os.environ['MESON_SOURCE_ROOT'], os.environ['MESON_SUBDIR'])
+dest = BASENAME.format(version)
+dest_path = os.path.join(source_dir, dest)
+extract_path = EXTRACTDIR.format(version)
+
+def get_sha256(zipf):
+    hasher = hashlib.sha256()
+    with open(zipf, 'rb') as f:
+        hasher.update(f.read())
+    return hasher.hexdigest()
+
+def download():
+    for url in (BASE_URL.format(version),):
+        print('Downloading {} to {}'.format(url, dest), file=sys.stderr)
+        try:
+            with open(dest_path, 'wb') as d:
+                f = urllib.request.urlopen(url, context=ctx)
+                d.write(f.read())
+            break
+        except urllib.error.URLError as ex:
+            print(ex, file=sys.stderr)
+            print('Failed to download from {!r}, trying mirror...'.format(url), file=sys.stderr)
+            continue
+    else:
+        curdir = os.path.dirname(sys.argv[0])
+        print('Couldn\'t download {!r}! Try downloading it manually and '
+              'placing it into {!r}'.format(dest, curdir), file=sys.stderr)
+
+def print_extract_dir():
+    'Print the extracted directory name'
+    print(extract_path, end='', file=sys.stderr)
+
+if os.path.isfile(dest_path):
+    found_sha256 = get_sha256(dest_path)
+    if found_sha256 == zip_sha256:
+        if os.path.isdir(os.path.join(source_dir, extract_path)):
+            print('{} already downloaded and extracted'.format(dest), file=sys.stderr)
+            print_extract_dir()
+            sys.exit(0)
+    else:
+        print('{} checksum mismatch, redownloading'.format(dest), file=sys.stderr)
+        download()
+else:
+    download()
+
+found_sha256 = get_sha256(dest_path)
+if found_sha256 != zip_sha256:
+    print('SHA256 of downloaded file {} was {} instead of {}'
+          ''.format(dest, found_sha256, zip_sha256), file=sys.stderr)
+    sys.exit(1)
+
+print('Extracting {}', file=sys.stderr)
+zf = zipfile.ZipFile(dest_path, "r")
+zf.extractall(path=os.path.join(source_dir, extract_path))
+print_extract_dir()

subprojects/webview2/meson.build

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+project('webview2', version : '1.0.2420.47')
+
+py3 = import('python3').find_python()
+
+if host_machine.system() != 'windows'
+  error('Can only download webview2 for Windows')
+endif
+
+message('Downloading and extracting webview2 nuget package')
+
+arch = target_machine.cpu_family()
+if arch != 'x86_64' and arch != 'x86' and arch != 'aarch64'
+  error('Unexpected architecture' + arch)
+endif
+
+zip_hash = '8e5a7307d71507edbbe02cac27215d71058bbd82cd256cef60f06b945907610a'
+version = meson.project_version()
+ret = run_command(py3, files('download-binary.py'), meson.project_version(), zip_hash,
+    check: true)
+
+base_path = join_paths(meson.current_source_dir(), 'webview2-@0@'.format(version),
+    'build', 'native')
+inc_dir = include_directories(join_paths(base_path, 'include'))
+lib_path = ''
+if arch == 'x86_64'
+  lib_path = join_paths(base_path, 'x64')
+elif arch == 'x86'
+  lib_path = join_paths(base_path, 'x86')
+else
+  lib_path = join_paths(base_path, 'arm64')
+endif
+
+cc = meson.get_compiler('c')
+loader_static = cc.find_library('WebView2LoaderStatic', dirs: [lib_path])
+webview2_dep = declare_dependency(include_directories: inc_dir,
+    dependencies: loader_static)