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.venv/Lib/site-packages/nbconvert/utils/io.py

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+"""io-related utilities"""
+
+# Copyright (c) Jupyter Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+import codecs
+import errno
+import os
+import random
+import shutil
+import sys
+
+
+def unicode_std_stream(stream="stdout"):
+    """Get a wrapper to write unicode to stdout/stderr as UTF-8.
+
+    This ignores environment variables and default encodings, to reliably write
+    unicode to stdout or stderr.
+
+    ::
+
+        unicode_std_stream().write(u'ł@e¶ŧ←')
+    """
+    assert stream in ("stdout", "stderr")
+    stream = getattr(sys, stream)
+
+    try:
+        stream_b = stream.buffer
+    except AttributeError:
+        # sys.stdout has been replaced - use it directly
+        return stream
+
+    return codecs.getwriter("utf-8")(stream_b)
+
+
+def unicode_stdin_stream():
+    """Get a wrapper to read unicode from stdin as UTF-8.
+
+    This ignores environment variables and default encodings, to reliably read unicode from stdin.
+
+    ::
+
+        totreat = unicode_stdin_stream().read()
+    """
+    stream = sys.stdin
+    try:
+        stream_b = stream.buffer
+    except AttributeError:
+        return stream
+
+    return codecs.getreader("utf-8")(stream_b)
+
+
+class FormatSafeDict(dict):
+    def __missing__(self, key):
+        return "{" + key + "}"
+
+
+try:
+    ENOLINK = errno.ENOLINK
+except AttributeError:
+    ENOLINK = 1998
+
+
+def link(src, dst):
+    """Hard links ``src`` to ``dst``, returning 0 or errno.
+
+    Note that the special errno ``ENOLINK`` will be returned if ``os.link`` isn't
+    supported by the operating system.
+    """
+
+    if not hasattr(os, "link"):
+        return ENOLINK
+    link_errno = 0
+    try:
+        os.link(src, dst)
+    except OSError as e:
+        link_errno = e.errno
+    return link_errno
+
+
+def link_or_copy(src, dst):
+    """Attempts to hardlink ``src`` to ``dst``, copying if the link fails.
+
+    Attempts to maintain the semantics of ``shutil.copy``.
+
+    Because ``os.link`` does not overwrite files, a unique temporary file
+    will be used if the target already exists, then that file will be moved
+    into place.
+    """
+
+    if os.path.isdir(dst):
+        dst = os.path.join(dst, os.path.basename(src))
+
+    link_errno = link(src, dst)
+    if link_errno == errno.EEXIST:
+        if os.stat(src).st_ino == os.stat(dst).st_ino:
+            # dst is already a hard link to the correct file, so we don't need
+            # to do anything else. If we try to link and rename the file
+            # anyway, we get duplicate files - see http://bugs.python.org/issue21876
+            return
+
+        new_dst = dst + f"-temp-{random.randint(1, 16**4):04X}"
+        try:
+            link_or_copy(src, new_dst)
+        except BaseException:
+            try:
+                os.remove(new_dst)
+            except OSError:
+                pass
+            raise
+        os.rename(new_dst, dst)
+    elif link_errno != 0:
+        # Either link isn't supported, or the filesystem doesn't support
+        # linking, or 'src' and 'dst' are on different filesystems.
+        shutil.copy(src, dst)
+
+
+def ensure_dir_exists(path, mode=0o755):
+    """ensure that a directory exists
+
+    If it doesn't exist, try to create it and protect against a race condition
+    if another process is doing the same.
+
+    The default permissions are 755, which differ from os.makedirs default of 777.
+    """
+    if not os.path.exists(path):
+        try:
+            os.makedirs(path, mode=mode)
+        except OSError as e:
+            if e.errno != errno.EEXIST:
+                raise
+    elif not os.path.isdir(path):
+        raise OSError("%r exists but is not a directory" % path)