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from __future__ import print_function, absolute_import, unicode_literals

"""
generate_pyi.py

This script generates the .pyi files for all PySide modules.
"""

import sys
import os
import io
import re
import subprocess
import argparse
import glob
from contextlib import contextmanager
from textwrap import dedent
import traceback


import logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger("generate_pyi")


# Make sure not to get .pyc in Python2.
sourcepath = os.path.splitext(__file__)[0] + ".py"

# Can we use forward references?
USE_PEP563 = sys.version_info[:2] >= (3, 7)

indent = " " * 4
is_py3 = sys.version_info[0] == 3
is_ci = os.environ.get("QTEST_ENVIRONMENT", "") == "ci"


class Writer(object):
    def __init__(self, outfile):
        self.outfile = outfile
        self.history = [True, True]

    def print(self, *args, **kw):
        # controlling too much blank lines
        if self.outfile:
            if args == () or args == ("",):
                # Python 2.7 glitch: Empty tuples have wrong encoding.
                # But we use that to skip too many blank lines:
                if self.history[-2:] == [True, True]:
                    return
                print("", file=self.outfile, **kw)
                self.history.append(True)
            else:
                print(*args, file=self.outfile, **kw)
                self.history.append(False)


class Formatter(Writer):
    """
    Formatter is formatting the signature listing of an enumerator.

    It is written as context managers in order to avoid many callbacks.
    The separation in formatter and enumerator is done to keep the
    unrelated tasks of enumeration and formatting apart.
    """
    @contextmanager
    def module(self, mod_name):
        self.mod_name = mod_name
        self.print("# Module", mod_name)
        self.print("import PySide2")
        from PySide2.support.signature import typing
        self.print("from PySide2.support.signature import typing")
        self.print("from PySide2.support.signature.mapping import (")
        self.print("    Virtual, Missing, Invalid, Default, Instance)")
        self.print()
        self.print("class Object(object): pass")
        self.print()
        self.print("import shiboken2 as Shiboken")
        self.print("Shiboken.Object = Object")
        self.print()
        # This line will be replaced by the missing imports.
        self.print("IMPORTS")
        yield

    @contextmanager
    def klass(self, class_name, class_str):
        self.class_name = class_name
        spaces = ""
        while "." in class_name:
            spaces += indent
            class_name = class_name.split(".", 1)[-1]
            class_str = class_str.split(".", 1)[-1]
        self.print()
        if not spaces:
            self.print()
        here = self.outfile.tell()
        self.print("{spaces}class {class_str}:".format(**locals()))
        self.print()
        pos = self.outfile.tell()
        self.spaces = spaces
        yield
        if pos == self.outfile.tell():
            # we have not written any function
            self.outfile.seek(here)
            self.outfile.truncate()
            # Note: we cannot use class_str when we have no body.
            self.print("{spaces}class {class_name}: ...".format(**locals()))
        if "<" in class_name:
            # This is happening in QtQuick for some reason:
            ## class QSharedPointer<QQuickItemGrabResult >:
            # We simply skip over this class.
            self.outfile.seek(here)
            self.outfile.truncate()

    @contextmanager
    def function(self, func_name, signature):
        key = func_name
        spaces = indent + self.spaces if self.class_name else ""
        if type(signature) == type([]):
            for sig in signature:
                self.print('{spaces}@typing.overload'.format(**locals()))
                self._function(func_name, sig, spaces)
        else:
            self._function(func_name, signature, spaces)
        yield key

    def _function(self, func_name, signature, spaces):
        # this would be nicer to get somehow together with the signature
        is_meth = re.match(r"\((\w*)", str(signature)).group(1) == "self"
        if self.class_name and not is_meth:
            self.print('{spaces}@staticmethod'.format(**locals()))
        self.print('{spaces}def {func_name}{signature}: ...'.format(**locals()))


def get_license_text():
    with io.open(sourcepath) as f:
        lines = f.readlines()
        license_line = next((lno for lno, line in enumerate(lines)
                             if "$QT_END_LICENSE$" in line))
    return "".join(lines[:license_line + 3])


def find_imports(text):
    return [imp for imp in PySide2.__all__ if imp + "." in text]


def generate_pyi(import_name, outpath, options):
    """
    Generates a .pyi file.

    Returns 1 If the result is valid, -1 if the result existed already
    and was skipped, else 0.

    This function will get called during a PySide build, and many concurrent
    process might try to create .pyi files. We let only one process at a
    time work on these files, but it will still be different processes which
    do the work.
    """
    pid = os.getpid()
    plainname = import_name.split(".")[-1]
    outfilepath = os.path.join(outpath, plainname + ".pyi")
    if options.skip and os.path.exists(outfilepath):
        logger.debug("{pid}:Skipped existing: {op}"
                     .format(op=os.path.basename(outfilepath), **locals()))
        return -1

    try:
        top = __import__(import_name)
        obj = getattr(top, plainname)
        if not getattr(obj, "__file__", None) or os.path.isdir(obj.__file__):
            raise ImportError("We do not accept a namespace as module {plainname}"
                              .format(**locals()))
        module = sys.modules[import_name]

        outfile = io.StringIO()
        fmt = Formatter(outfile)
        enu = HintingEnumerator(fmt)
        fmt.print(get_license_text())  # which has encoding, already
        need_imports = not USE_PEP563
        if USE_PEP563:
            fmt.print("from __future__ import annotations")
            fmt.print()
        fmt.print(dedent('''\
            """
            This file contains the exact signatures for all functions in module
            {import_name}, except for defaults which are replaced by "...".
            """
            '''.format(**locals())))
        enu.module(import_name)
        fmt.print()
        fmt.print("# eof")

    except ImportError as e:
        logger.debug("{pid}:Import problem with module {plainname}: {e}".format(**locals()))
        return 0

    with open(outfilepath, "w") as realfile:
        wr = Writer(realfile)
        outfile.seek(0)
        while True:
            line = outfile.readline()
            if not line:
                break
            line = line.rstrip()
            # we remove the IMPORTS marker and insert imports if needed
            if line == "IMPORTS":
                if need_imports:
                    for mod_name in find_imports(outfile.getvalue()):
                        imp = "PySide2." + mod_name
                        if imp != import_name:
                            wr.print("import " + imp)
                wr.print("import " + import_name)
                wr.print()
                wr.print()
            else:
                wr.print(line)
    logger.info("Generated: {outfilepath}".format(**locals()))
    if is_py3:
        # Python 3: We can check the file directly if the syntax is ok.
        try:
            subprocess.check_output([sys.executable, outfilepath])
        except Exception as e:
            print("+++ Problem executing test, although it works")
            traceback.print_exc(file=sys.stdout)
    return 1


@contextmanager
def single_process(lockdir):
    try:
        os.mkdir(lockdir)
        try:
            yield lockdir
        finally:
            # make sure to cleanup, even if we leave with CTRL-C
            os.rmdir(lockdir)
    except OSError:
        yield None


def generate_all_pyi(outpath, options):
    ps = os.pathsep
    if options.sys_path:
        # make sure to propagate the paths from sys_path to subprocesses
        sys_path = [os.path.normpath(_) for _ in options.sys_path]
        sys.path[0:0] = sys_path
        pypath = ps.join(sys_path)
        os.environ["PYTHONPATH"] = pypath

    # now we can import
    global PySide2, inspect, HintingEnumerator
    import PySide2
    from PySide2.support.signature import inspect
    from PySide2.support.signature.lib.enum_sig import HintingEnumerator

    valid = check = 0
    if not outpath:
        outpath = os.path.dirname(PySide2.__file__)
    lockdir = os.path.join(outpath, "generate_pyi.lockfile")
    with single_process(lockdir) as locked:
        if locked:
            if is_ci:
                # When COIN is running, we sometimes get racing conditions with
                # the windows manifest tool which wants access to a module that
                # we already have imported. But when we wait until all binaries
                # are created, that cannot happen, because we are then the last
                # process, and the tool has already been run.
                bin_pattern = "Qt*.pyd" if sys.platform == "win32" else "Qt*.so"
                search = os.path.join(PySide2.__path__[0], bin_pattern)
                if len(glob.glob(search)) < len(PySide2.__all__):
                    return
            for mod_name in PySide2.__all__:
                import_name = "PySide2." + mod_name
                step = generate_pyi(import_name, outpath, options)
                valid += abs(step)
                check += step

            npyi = len(PySide2.__all__)
            # Prevent too many messages when '--reuse-build' is used. We check that
            # all files are created, but at least one was really computed.
            if valid == npyi and check != -npyi:
                logger.info("+++ All {npyi} .pyi files have been created.".format(**locals()))


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    subparsers = parser.add_subparsers(dest="command")
    # create the parser for the "run" command
    parser_run = subparsers.add_parser("run",
        help="run the generation",
        description="This script generates the .pyi file for all PySide modules.")
    parser_run.add_argument("--skip", action="store_true",
        help="skip existing files")
    parser_run.add_argument("--quiet", action="store_true", help="Run quietly")
    parser_run.add_argument("--outpath",
        help="the output directory (default = binary location)")
    parser_run.add_argument("--sys-path", nargs="+",
        help="a list of strings prepended to sys.path")
    options = parser.parse_args()
    if options.command == "run":
        if options.quiet:
            logger.setLevel(logging.WARNING)
        outpath = options.outpath
        if outpath and not os.path.exists(outpath):
            os.makedirs(outpath)
            logger.info("+++ Created path {outpath}".format(**locals()))
        generate_all_pyi(outpath, options=options)
    else:
        parser_run.print_help()
        sys.exit(1)