interface compatibility with before rewrite (#1479)

Ensure that what ran with virtualenv 17 will continue running in a post
rewrite world minus the deprecated flags, plus the relocatable feature.

Signed-off-by: Bernat Gabor <bgabor8@bloomberg.net>

4 files changed, 212 insertions, 0 deletions

diff --git a/src/virtualenv/util/path/__init__.py b/src/virtualenv/util/path/__init__.py
new file mode 100644
index 0000000..ab5db8e
--- /dev/null
+++ b/src/virtualenv/util/path/__init__.py
@@ -0,0 +1,12 @@
+from __future__ import absolute_import, unicode_literals
+
+from ._pathlib import Path
+from ._sync import copy, ensure_dir, symlink, symlink_or_copy
+
+__all__ = (
+    "ensure_dir",
+    "symlink_or_copy",
+    "symlink",
+    "copy",
+    "Path",
+)
diff --git a/src/virtualenv/util/path/_pathlib/__init__.py b/src/virtualenv/util/path/_pathlib/__init__.py
new file mode 100644
index 0000000..3b18d3d
--- /dev/null
+++ b/src/virtualenv/util/path/_pathlib/__init__.py
@@ -0,0 +1,40 @@
+from __future__ import absolute_import, unicode_literals
+
+import sys
+
+import six
+
+if six.PY3:
+    from pathlib import Path
+
+    if sys.version_info[0:2] == (3, 4):
+        # no read/write text on python3.4
+        BuiltinPath = Path
+
+        class Path(type(BuiltinPath())):
+            def read_text(self, encoding=None, errors=None):
+                """
+                Open the file in text mode, read it, and close the file.
+                """
+                with self.open(mode="r", encoding=encoding, errors=errors) as f:
+                    return f.read()
+
+            def write_text(self, data, encoding=None, errors=None):
+                """
+                Open the file in text mode, write to it, and close the file.
+                """
+                if not isinstance(data, str):
+                    raise TypeError("data must be str, not %s" % data.__class__.__name__)
+                with self.open(mode="w", encoding=encoding, errors=errors) as f:
+                    return f.write(data)
+
+
+else:
+    if sys.platform == "win32":
+        # workaround for https://github.com/mcmtroffaes/pathlib2/issues/56
+        from .via_os_path import Path
+    else:
+        from pathlib2 import Path
+
+
+__all__ = ("Path",)
diff --git a/src/virtualenv/util/path/_pathlib/via_os_path.py b/src/virtualenv/util/path/_pathlib/via_os_path.py
new file mode 100644
index 0000000..1dddd7e
--- /dev/null
+++ b/src/virtualenv/util/path/_pathlib/via_os_path.py
@@ -0,0 +1,110 @@
+from __future__ import absolute_import, unicode_literals
+
+import os
+from contextlib import contextmanager
+
+import six
+
+
+class Path(object):
+    def __init__(self, path):
+        self._path = path._path if isinstance(path, Path) else six.ensure_text(path)
+
+    def __repr__(self):
+        return six.ensure_str("Path({})".format(self._path))
+
+    def __str__(self):
+        return six.ensure_str(self._path)
+
+    def __div__(self, other):
+        return Path(os.path.join(self._path, other._path if isinstance(other, Path) else six.ensure_text(other)))
+
+    def __truediv__(self, other):
+        return self.__div__(other)
+
+    def __eq__(self, other):
+        return self._path == (other._path if isinstance(other, Path) else None)
+
+    def __ne__(self, other):
+        return not (self == other)
+
+    def __hash__(self):
+        return hash(self._path)
+
+    def exists(self):
+        return os.path.exists(self._path)
+
+    def absolute(self):
+        return Path(os.path.abspath(self._path))
+
+    @property
+    def parent(self):
+        return Path(os.path.abspath(os.path.join(self._path, os.path.pardir)))
+
+    def resolve(self):
+        return Path(os.path.realpath(self._path))
+
+    @property
+    def name(self):
+        return os.path.basename(self._path)
+
+    @property
+    def parts(self):
+        return self._path.split(os.sep)
+
+    def is_file(self):
+        return os.path.isfile(self._path)
+
+    def is_dir(self):
+        return os.path.isdir(self._path)
+
+    def mkdir(self, parents=True, exist_ok=True):
+        if not self.exists() and exist_ok:
+            os.makedirs(self._path)
+
+    def read_text(self, encoding="utf-8"):
+        with open(self._path, "rb") as file_handler:
+            return file_handler.read().decode(encoding)
+
+    def write_text(self, text, encoding="utf-8"):
+        with open(self._path, "wb") as file_handler:
+            file_handler.write(text.encode(encoding))
+
+    def iterdir(self):
+        for p in os.listdir(self._path):
+            yield Path(os.path.join(self._path, p))
+
+    @property
+    def suffix(self):
+        _, ext = os.path.splitext(self.name)
+        return ext
+
+    @property
+    def stem(self):
+        base, _ = os.path.splitext(self.name)
+        return base
+
+    @contextmanager
+    def open(self, mode="r"):
+        with open(self._path, mode) as file_handler:
+            yield file_handler
+
+    @property
+    def parents(self):
+        result = []
+        parts = self.parts
+        for i in range(len(parts)):
+            result.append(Path(os.sep.join(parts[0 : i + 1])))
+        return result
+
+    def unlink(self):
+        os.remove(self._path)
+
+    def with_name(self, name):
+        return self.parent / name
+
+    def is_symlink(self):
+        return os.path.islink(self._path)
+
+
+__all__ = ("Path",)
diff --git a/src/virtualenv/util/path/_sync.py b/src/virtualenv/util/path/_sync.py
new file mode 100644
index 0000000..c3d6111
--- /dev/null
+++ b/src/virtualenv/util/path/_sync.py
@@ -0,0 +1,50 @@
+from __future__ import absolute_import, unicode_literals
+
+import logging
+import os
+import shutil
+from functools import partial
+
+import six
+
+HAS_SYMLINK = hasattr(os, "symlink")
+
+
+def ensure_dir(path):
+    if not path.exists():
+        logging.debug("created %s", six.ensure_text(str(path)))
+        os.makedirs(six.ensure_text(str(path)))
+
+
+def symlink_or_copy(do_copy, src, dst, relative_symlinks_ok=False):
+    """
+    Try symlinking a target, and if that fails, fall back to copying.
+    """
+    if do_copy is False and HAS_SYMLINK is False:  # if no symlink, always use copy
+        do_copy = True
+    if not do_copy:
+        try:
+            if not dst.is_symlink():  # can't link to itself!
+                if relative_symlinks_ok:
+                    assert src.parent == dst.parent
+                    os.symlink(six.ensure_text(src.name), six.ensure_text(str(dst)))
+                else:
+                    os.symlink(six.ensure_text(str(src)), six.ensure_text(str(dst)))
+        except OSError as exception:
+            logging.warning(
+                "symlink failed %r, for %s to %s, will try copy",
+                exception,
+                six.ensure_text(str(src)),
+                six.ensure_text(str(dst)),
+            )
+            do_copy = True
+    if do_copy:
+        copier = shutil.copy2 if src.is_file() else shutil.copytree
+        copier(six.ensure_text(str(src)), six.ensure_text(str(dst)))
+    logging.debug("%s %s to %s", "copy" if do_copy else "symlink", six.ensure_text(str(src)), six.ensure_text(str(dst)))
+
+
+symlink = partial(symlink_or_copy, False)
+copy = partial(symlink_or_copy, True)
+
+__all__ = ("ensure_dir", "symlink", "copy", "symlink_or_copy")