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stbi/Lib/site-packages/pip/_vendor/pep517/_in_process.py

+"""This is invoked in a subprocess to call the build backend hooks.
+
+It expects:
+- Command line args: hook_name, control_dir
+- Environment variables:
+      PEP517_BUILD_BACKEND=entry.point:spec
+      PEP517_BACKEND_PATH=paths (separated with os.pathsep)
+- control_dir/input.json:
+  - {"kwargs": {...}}
+
+Results:
+- control_dir/output.json
+  - {"return_val": ...}
+"""
+from glob import glob
+from importlib import import_module
+import json
+import os
+import os.path
+from os.path import join as pjoin
+import re
+import shutil
+import sys
+import traceback
+
+# This file is run as a script, and `import compat` is not zip-safe, so we
+# include write_json() and read_json() from compat.py.
+#
+# Handle reading and writing JSON in UTF-8, on Python 3 and 2.
+
+if sys.version_info[0] >= 3:
+    # Python 3
+    def write_json(obj, path, **kwargs):
+        with open(path, 'w', encoding='utf-8') as f:
+            json.dump(obj, f, **kwargs)
+
+    def read_json(path):
+        with open(path, 'r', encoding='utf-8') as f:
+            return json.load(f)
+
+else:
+    # Python 2
+    def write_json(obj, path, **kwargs):
+        with open(path, 'wb') as f:
+            json.dump(obj, f, encoding='utf-8', **kwargs)
+
+    def read_json(path):
+        with open(path, 'rb') as f:
+            return json.load(f)
+
+
+class BackendUnavailable(Exception):
+    """Raised if we cannot import the backend"""
+    def __init__(self, traceback):
+        self.traceback = traceback
+
+
+class BackendInvalid(Exception):
+    """Raised if the backend is invalid"""
+    def __init__(self, message):
+        self.message = message
+
+
+class HookMissing(Exception):
+    """Raised if a hook is missing and we are not executing the fallback"""
+
+
+def contained_in(filename, directory):
+    """Test if a file is located within the given directory."""
+    filename = os.path.normcase(os.path.abspath(filename))
+    directory = os.path.normcase(os.path.abspath(directory))
+    return os.path.commonprefix([filename, directory]) == directory
+
+
+def _build_backend():
+    """Find and load the build backend"""
+    # Add in-tree backend directories to the front of sys.path.
+    backend_path = os.environ.get('PEP517_BACKEND_PATH')
+    if backend_path:
+        extra_pathitems = backend_path.split(os.pathsep)
+        sys.path[:0] = extra_pathitems
+
+    ep = os.environ['PEP517_BUILD_BACKEND']
+    mod_path, _, obj_path = ep.partition(':')
+    try:
+        obj = import_module(mod_path)
+    except ImportError:
+        raise BackendUnavailable(traceback.format_exc())
+
+    if backend_path:
+        if not any(
+            contained_in(obj.__file__, path)
+            for path in extra_pathitems
+        ):
+            raise BackendInvalid("Backend was not loaded from backend-path")
+
+    if obj_path:
+        for path_part in obj_path.split('.'):
+            obj = getattr(obj, path_part)
+    return obj
+
+
+def get_requires_for_build_wheel(config_settings):
+    """Invoke the optional get_requires_for_build_wheel hook
+
+    Returns [] if the hook is not defined.
+    """
+    backend = _build_backend()
+    try:
+        hook = backend.get_requires_for_build_wheel
+    except AttributeError:
+        return []
+    else:
+        return hook(config_settings)
+
+
+def prepare_metadata_for_build_wheel(
+        metadata_directory, config_settings, _allow_fallback):
+    """Invoke optional prepare_metadata_for_build_wheel
+
+    Implements a fallback by building a wheel if the hook isn't defined,
+    unless _allow_fallback is False in which case HookMissing is raised.
+    """
+    backend = _build_backend()
+    try:
+        hook = backend.prepare_metadata_for_build_wheel
+    except AttributeError:
+        if not _allow_fallback:
+            raise HookMissing()
+        return _get_wheel_metadata_from_wheel(backend, metadata_directory,
+                                              config_settings)
+    else:
+        return hook(metadata_directory, config_settings)
+
+
+WHEEL_BUILT_MARKER = 'PEP517_ALREADY_BUILT_WHEEL'
+
+
+def _dist_info_files(whl_zip):
+    """Identify the .dist-info folder inside a wheel ZipFile."""
+    res = []
+    for path in whl_zip.namelist():
+        m = re.match(r'[^/\\]+-[^/\\]+\.dist-info/', path)
+        if m:
+            res.append(path)
+    if res:
+        return res
+    raise Exception("No .dist-info folder found in wheel")
+
+
+def _get_wheel_metadata_from_wheel(
+        backend, metadata_directory, config_settings):
+    """Build a wheel and extract the metadata from it.
+
+    Fallback for when the build backend does not
+    define the 'get_wheel_metadata' hook.
+    """
+    from zipfile import ZipFile
+    whl_basename = backend.build_wheel(metadata_directory, config_settings)
+    with open(os.path.join(metadata_directory, WHEEL_BUILT_MARKER), 'wb'):
+        pass  # Touch marker file
+
+    whl_file = os.path.join(metadata_directory, whl_basename)
+    with ZipFile(whl_file) as zipf:
+        dist_info = _dist_info_files(zipf)
+        zipf.extractall(path=metadata_directory, members=dist_info)
+    return dist_info[0].split('/')[0]
+
+
+def _find_already_built_wheel(metadata_directory):
+    """Check for a wheel already built during the get_wheel_metadata hook.
+    """
+    if not metadata_directory:
+        return None
+    metadata_parent = os.path.dirname(metadata_directory)
+    if not os.path.isfile(pjoin(metadata_parent, WHEEL_BUILT_MARKER)):
+        return None
+
+    whl_files = glob(os.path.join(metadata_parent, '*.whl'))
+    if not whl_files:
+        print('Found wheel built marker, but no .whl files')
+        return None
+    if len(whl_files) > 1:
+        print('Found multiple .whl files; unspecified behaviour. '
+              'Will call build_wheel.')
+        return None
+
+    # Exactly one .whl file
+    return whl_files[0]
+
+
+def build_wheel(wheel_directory, config_settings, metadata_directory=None):
+    """Invoke the mandatory build_wheel hook.
+
+    If a wheel was already built in the
+    prepare_metadata_for_build_wheel fallback, this
+    will copy it rather than rebuilding the wheel.
+    """
+    prebuilt_whl = _find_already_built_wheel(metadata_directory)
+    if prebuilt_whl:
+        shutil.copy2(prebuilt_whl, wheel_directory)
+        return os.path.basename(prebuilt_whl)
+
+    return _build_backend().build_wheel(wheel_directory, config_settings,
+                                        metadata_directory)
+
+
+def get_requires_for_build_sdist(config_settings):
+    """Invoke the optional get_requires_for_build_wheel hook
+
+    Returns [] if the hook is not defined.
+    """
+    backend = _build_backend()
+    try:
+        hook = backend.get_requires_for_build_sdist
+    except AttributeError:
+        return []
+    else:
+        return hook(config_settings)
+
+
+class _DummyException(Exception):
+    """Nothing should ever raise this exception"""
+
+
+class GotUnsupportedOperation(Exception):
+    """For internal use when backend raises UnsupportedOperation"""
+    def __init__(self, traceback):
+        self.traceback = traceback
+
+
+def build_sdist(sdist_directory, config_settings):
+    """Invoke the mandatory build_sdist hook."""
+    backend = _build_backend()
+    try:
+        return backend.build_sdist(sdist_directory, config_settings)
+    except getattr(backend, 'UnsupportedOperation', _DummyException):
+        raise GotUnsupportedOperation(traceback.format_exc())
+
+
+HOOK_NAMES = {
+    'get_requires_for_build_wheel',
+    'prepare_metadata_for_build_wheel',
+    'build_wheel',
+    'get_requires_for_build_sdist',
+    'build_sdist',
+}
+
+
+def main():
+    if len(sys.argv) < 3:
+        sys.exit("Needs args: hook_name, control_dir")
+    hook_name = sys.argv[1]
+    control_dir = sys.argv[2]
+    if hook_name not in HOOK_NAMES:
+        sys.exit("Unknown hook: %s" % hook_name)
+    hook = globals()[hook_name]
+
+    hook_input = read_json(pjoin(control_dir, 'input.json'))
+
+    json_out = {'unsupported': False, 'return_val': None}
+    try:
+        json_out['return_val'] = hook(**hook_input['kwargs'])
+    except BackendUnavailable as e:
+        json_out['no_backend'] = True
+        json_out['traceback'] = e.traceback
+    except BackendInvalid as e:
+        json_out['backend_invalid'] = True
+        json_out['backend_error'] = e.message
+    except GotUnsupportedOperation as e:
+        json_out['unsupported'] = True
+        json_out['traceback'] = e.traceback
+    except HookMissing:
+        json_out['hook_missing'] = True
+
+    write_json(json_out, pjoin(control_dir, 'output.json'), indent=2)
+
+
+if __name__ == '__main__':
+    main()