Add --vsenv command line option and active VS only when needed

1 files changed, 100 insertions, 0 deletions

diff --git a/mesonbuild/mesonlib/vsenv.py b/mesonbuild/mesonlib/vsenv.py
new file mode 100644
index 0000000..1966634
--- /dev/null
+++ b/mesonbuild/mesonlib/vsenv.py
@@ -0,0 +1,100 @@
+import os
+import subprocess
+import json
+import pathlib
+import shutil
+import tempfile
+
+from .. import mlog
+from .universal import MesonException, is_windows
+
+
+bat_template = '''@ECHO OFF
+
+call "{}"
+
+ECHO {}
+SET
+'''
+
+# If on Windows and VS is installed but not set up in the environment,
+# set it to be runnable. In this way Meson can be directly invoked
+# from any shell, VS Code etc.
+def _setup_vsenv(force: bool) -> bool:
+    if not is_windows():
+        return False
+    if os.environ.get('OSTYPE') == 'cygwin':
+        return False
+    if 'Visual Studio' in os.environ['PATH']:
+        return False
+    # VSINSTALL is set when running setvars from a Visual Studio installation
+    # Tested with Visual Studio 2012 and 2017
+    if 'VSINSTALLDIR' in os.environ:
+        return False
+    # Check explicitly for cl when on Windows
+    if shutil.which('cl.exe'):
+        return False
+    if not force:
+        if shutil.which('cc'):
+            return False
+        if shutil.which('gcc'):
+            return False
+        if shutil.which('clang'):
+            return False
+        if shutil.which('clang-cl'):
+            return False
+
+    root = os.environ.get("ProgramFiles(x86)") or os.environ.get("ProgramFiles")
+    bat_locator_bin = pathlib.Path(root, 'Microsoft Visual Studio/Installer/vswhere.exe')
+    if not bat_locator_bin.exists():
+        raise MesonException(f'Could not find {bat_locator_bin}')
+    bat_json = subprocess.check_output(
+        [
+            str(bat_locator_bin),
+            '-latest',
+            '-prerelease',
+            '-requiresAny',
+            '-requires', 'Microsoft.VisualStudio.Component.VC.Tools.x86.x64',
+            '-products', '*',
+            '-utf8',
+            '-format',
+            'json'
+        ]
+    )
+    bat_info = json.loads(bat_json)
+    if not bat_info:
+        # VS installer instelled but not VS itself maybe?
+        raise MesonException(f'Could not parse vswhere.exe output')
+    bat_root = pathlib.Path(bat_info[0]['installationPath'])
+    bat_path = bat_root / 'VC/Auxiliary/Build/vcvars64.bat'
+    if not bat_path.exists():
+        raise MesonException(f'Could not find {bat_path}')
+
+    mlog.log('Activating VS', bat_info[0]['catalog']['productDisplayVersion'])
+    bat_separator = '---SPLIT---'
+    bat_contents = bat_template.format(bat_path, bat_separator)
+    bat_file = tempfile.NamedTemporaryFile('w', suffix='.bat', encoding='utf-8')
+    bat_file.write(bat_contents)
+    bat_file.flush()
+    bat_output = subprocess.check_output(str(bat_file), universal_newlines=True)
+    bat_lines = bat_output.split('\n')
+    bat_separator_seen = False
+    for bat_line in bat_lines:
+        if bat_line == bat_separator:
+            bat_separator_seen = True
+            continue
+        if not bat_separator_seen:
+            continue
+        if not bat_line:
+            continue
+        k, v = bat_line.split('=', 1)
+        os.environ[k] = v
+    return True
+
+def setup_vsenv(force: bool = False):
+    try:
+        _setup_vsenv(force)
+    except MesonException:
+        if force:
+            raise
+        mlog.warning('Failed to activate VS environment:', str(e))