Calling GIO with ctypes

ctypes_gio.py

import ctypes
import ctypes.util


class GioURI(object):
    """Use gio URI function g_file_get_uri. Paths must be utf-8 encoded.
    """
    name = "GIO"

    def __init__(self):
        self.libgio = self.get_library()
        self.available = bool(self.libgio)

    def get_library(self):
        lib_name = ctypes.util.find_library("gio-2")
        try:
            return ctypes.cdll.LoadLibrary(lib_name)
        except OSError:
            return False

    def uri(self, path):
        print(b"getting g_file_ptr for %s" % path)
        g_file_ptr = self.libgio.g_file_new_for_path(path)
        if not g_file_ptr:
            raise RuntimeError("No gfile pointer received for {0!r}".format(
                path))

        try:
            print("getting uri_ptr with %s" % g_file_ptr)
            uri_ptr = self.libgio.g_file_get_uri(g_file_ptr)
        except:
            print("got exception")
            raise
        finally:
            print("free g_file_ptr")
            self.libgio.g_object_unref(g_file_ptr)
        if not uri_ptr:
            print("free uri_ptr")
            self.libgio.g_free(uri_ptr)
            raise RuntimeError("No URI received from the gfile pointer for "
                               "{0!r}".format(path))

        try:
            print("getting uri")
            uri = ctypes.c_char_p(uri_ptr).value
        except:
            print("got exception")
            raise
        finally:
            print("free uri_ptr")
            self.libgio.g_free(uri_ptr)
        return uri


def test():
    gio = GioURI()
    if not gio.available:
        print("no gio")
        return
    # this will crash at some point...
    for i in range(25):
        print("Step %s" % i)
        gio.uri(b"/foo/bar")

if __name__ == '__main__':
    test()