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9e6493849e
Merge `_WindowsPathInfo` and `_PosixPathInfo` classes into a new `_StatResultInfo` class. On Windows, this means relying on `os.stat()` rather than `os.path.isfile()` and friends, which is a little slower. But there's value in making the code easier to maintain, and we're going to need the stat result for implementing `size()`, `mode()` etc. Also move the classes from `pathlib._os` to `pathlib` proper.
303 lines
9.3 KiB
Python
303 lines
9.3 KiB
Python
"""
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Low-level OS functionality wrappers used by pathlib.
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"""
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from errno import *
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from io import TextIOWrapper, text_encoding
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import os
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import sys
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try:
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import fcntl
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except ImportError:
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fcntl = None
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try:
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import posix
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except ImportError:
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posix = None
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try:
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import _winapi
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except ImportError:
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_winapi = None
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def _get_copy_blocksize(infd):
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"""Determine blocksize for fastcopying on Linux.
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Hopefully the whole file will be copied in a single call.
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The copying itself should be performed in a loop 'till EOF is
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reached (0 return) so a blocksize smaller or bigger than the actual
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file size should not make any difference, also in case the file
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content changes while being copied.
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"""
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try:
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blocksize = max(os.fstat(infd).st_size, 2 ** 23) # min 8 MiB
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except OSError:
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blocksize = 2 ** 27 # 128 MiB
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# On 32-bit architectures truncate to 1 GiB to avoid OverflowError,
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# see gh-82500.
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if sys.maxsize < 2 ** 32:
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blocksize = min(blocksize, 2 ** 30)
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return blocksize
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if fcntl and hasattr(fcntl, 'FICLONE'):
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def _ficlone(source_fd, target_fd):
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"""
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Perform a lightweight copy of two files, where the data blocks are
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copied only when modified. This is known as Copy on Write (CoW),
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instantaneous copy or reflink.
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"""
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fcntl.ioctl(target_fd, fcntl.FICLONE, source_fd)
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else:
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_ficlone = None
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if posix and hasattr(posix, '_fcopyfile'):
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def _fcopyfile(source_fd, target_fd):
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"""
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Copy a regular file content using high-performance fcopyfile(3)
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syscall (macOS).
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"""
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posix._fcopyfile(source_fd, target_fd, posix._COPYFILE_DATA)
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else:
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_fcopyfile = None
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if hasattr(os, 'copy_file_range'):
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def _copy_file_range(source_fd, target_fd):
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"""
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Copy data from one regular mmap-like fd to another by using a
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high-performance copy_file_range(2) syscall that gives filesystems
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an opportunity to implement the use of reflinks or server-side
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copy.
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This should work on Linux >= 4.5 only.
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"""
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blocksize = _get_copy_blocksize(source_fd)
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offset = 0
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while True:
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sent = os.copy_file_range(source_fd, target_fd, blocksize,
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offset_dst=offset)
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if sent == 0:
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break # EOF
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offset += sent
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else:
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_copy_file_range = None
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if hasattr(os, 'sendfile'):
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def _sendfile(source_fd, target_fd):
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"""Copy data from one regular mmap-like fd to another by using
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high-performance sendfile(2) syscall.
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This should work on Linux >= 2.6.33 only.
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"""
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blocksize = _get_copy_blocksize(source_fd)
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offset = 0
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while True:
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sent = os.sendfile(target_fd, source_fd, offset, blocksize)
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if sent == 0:
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break # EOF
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offset += sent
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else:
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_sendfile = None
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if _winapi and hasattr(_winapi, 'CopyFile2'):
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def copyfile2(source, target):
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"""
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Copy from one file to another using CopyFile2 (Windows only).
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"""
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_winapi.CopyFile2(source, target, 0)
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else:
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copyfile2 = None
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def copyfileobj(source_f, target_f):
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"""
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Copy data from file-like object source_f to file-like object target_f.
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"""
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try:
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source_fd = source_f.fileno()
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target_fd = target_f.fileno()
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except Exception:
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pass # Fall through to generic code.
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else:
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try:
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# Use OS copy-on-write where available.
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if _ficlone:
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try:
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_ficlone(source_fd, target_fd)
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return
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except OSError as err:
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if err.errno not in (EBADF, EOPNOTSUPP, ETXTBSY, EXDEV):
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raise err
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# Use OS copy where available.
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if _fcopyfile:
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try:
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_fcopyfile(source_fd, target_fd)
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return
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except OSError as err:
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if err.errno not in (EINVAL, ENOTSUP):
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raise err
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if _copy_file_range:
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try:
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_copy_file_range(source_fd, target_fd)
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return
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except OSError as err:
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if err.errno not in (ETXTBSY, EXDEV):
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raise err
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if _sendfile:
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try:
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_sendfile(source_fd, target_fd)
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return
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except OSError as err:
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if err.errno != ENOTSOCK:
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raise err
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except OSError as err:
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# Produce more useful error messages.
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err.filename = source_f.name
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err.filename2 = target_f.name
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raise err
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# Last resort: copy with fileobj read() and write().
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read_source = source_f.read
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write_target = target_f.write
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while buf := read_source(1024 * 1024):
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write_target(buf)
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def _open_reader(obj):
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cls = type(obj)
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try:
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open_reader = cls.__open_reader__
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except AttributeError:
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cls_name = cls.__name__
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raise TypeError(f"{cls_name} can't be opened for reading") from None
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else:
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return open_reader(obj)
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def _open_writer(obj, mode):
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cls = type(obj)
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try:
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open_writer = cls.__open_writer__
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except AttributeError:
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cls_name = cls.__name__
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raise TypeError(f"{cls_name} can't be opened for writing") from None
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else:
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return open_writer(obj, mode)
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def _open_updater(obj, mode):
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cls = type(obj)
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try:
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open_updater = cls.__open_updater__
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except AttributeError:
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cls_name = cls.__name__
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raise TypeError(f"{cls_name} can't be opened for updating") from None
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else:
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return open_updater(obj, mode)
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def vfsopen(obj, mode='r', buffering=-1, encoding=None, errors=None,
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newline=None):
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"""
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Open the file pointed to by this path and return a file object, as
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the built-in open() function does.
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Unlike the built-in open() function, this function additionally accepts
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'openable' objects, which are objects with any of these special methods:
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__open_reader__()
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__open_writer__(mode)
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__open_updater__(mode)
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'__open_reader__' is called for 'r' mode; '__open_writer__' for 'a', 'w'
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and 'x' modes; and '__open_updater__' for 'r+' and 'w+' modes. If text
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mode is requested, the result is wrapped in an io.TextIOWrapper object.
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"""
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if buffering != -1:
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raise ValueError("buffer size can't be customized")
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text = 'b' not in mode
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if text:
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# Call io.text_encoding() here to ensure any warning is raised at an
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# appropriate stack level.
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encoding = text_encoding(encoding)
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try:
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return open(obj, mode, buffering, encoding, errors, newline)
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except TypeError:
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pass
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if not text:
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if encoding is not None:
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raise ValueError("binary mode doesn't take an encoding argument")
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if errors is not None:
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raise ValueError("binary mode doesn't take an errors argument")
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if newline is not None:
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raise ValueError("binary mode doesn't take a newline argument")
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mode = ''.join(sorted(c for c in mode if c not in 'bt'))
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if mode == 'r':
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stream = _open_reader(obj)
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elif mode in ('a', 'w', 'x'):
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stream = _open_writer(obj, mode)
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elif mode in ('+r', '+w'):
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stream = _open_updater(obj, mode[1])
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else:
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raise ValueError(f'invalid mode: {mode}')
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if text:
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stream = TextIOWrapper(stream, encoding, errors, newline)
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return stream
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def vfspath(obj):
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"""
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Return the string representation of a virtual path object.
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"""
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cls = type(obj)
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try:
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vfspath_method = cls.__vfspath__
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except AttributeError:
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cls_name = cls.__name__
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raise TypeError(f"expected JoinablePath object, not {cls_name}") from None
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else:
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return vfspath_method(obj)
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def ensure_distinct_paths(source, target):
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"""
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Raise OSError(EINVAL) if the other path is within this path.
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"""
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# Note: there is no straightforward, foolproof algorithm to determine
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# if one directory is within another (a particularly perverse example
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# would be a single network share mounted in one location via NFS, and
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# in another location via CIFS), so we simply checks whether the
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# other path is lexically equal to, or within, this path.
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if source == target:
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err = OSError(EINVAL, "Source and target are the same path")
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elif source in target.parents:
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err = OSError(EINVAL, "Source path is a parent of target path")
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else:
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return
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err.filename = vfspath(source)
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err.filename2 = vfspath(target)
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raise err
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def ensure_different_files(source, target):
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"""
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Raise OSError(EINVAL) if both paths refer to the same file.
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"""
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try:
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source_file_id = source.info._file_id
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target_file_id = target.info._file_id
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except AttributeError:
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if source != target:
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return
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else:
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try:
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if source_file_id() != target_file_id():
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return
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except (OSError, ValueError):
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return
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err = OSError(EINVAL, "Source and target are the same file")
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err.filename = vfspath(source)
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err.filename2 = vfspath(target)
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raise err
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