"""Utility functions for copying files and directory trees.

XXX The functions here don't copy the resource fork or other metadata on Mac.

"""

import os

import sys

import stat

from os.path import abspath

import fnmatch

__all__ = ["copyfileobj","copyfile","copymode","copystat","copy","copy2",

           "copytree","move","rmtree","Error"]

class Error(EnvironmentError):

    pass

try:

    WindowsError

except NameError:

    WindowsError = None

def copyfileobj(fsrc, fdst, length=16*1024):

    """copy data from file-like object fsrc to file-like object fdst"""

    while 1:

        buf = fsrc.read(length)

        if not buf:

            break

        fdst.write(buf)

def _samefile(src, dst):

    # Macintosh, Unix.

    if hasattr(os.path,'samefile'):

        try:

            return os.path.samefile(src, dst)

        except OSError:

            return False

    # All other platforms: check for same pathname.

    return (os.path.normcase(os.path.abspath(src)) ==

            os.path.normcase(os.path.abspath(dst)))

def copyfile(src, dst):

    """Copy data from src to dst"""

    if _samefile(src, dst):

        raise Error, "`%s` and `%s` are the same file" % (src, dst)

    fsrc = None

    fdst = None

    try:

        fsrc = open(src, 'rb')

        fdst = open(dst, 'wb')

        copyfileobj(fsrc, fdst)

    finally:

        if fdst:

            fdst.close()

        if fsrc:

            fsrc.close()

def copymode(src, dst):

    """Copy mode bits from src to dst"""

    if hasattr(os, 'chmod'):

        st = os.stat(src)

        mode = stat.S_IMODE(st.st_mode)

        os.chmod(dst, mode)

def copystat(src, dst):

    """Copy all stat info (mode bits, atime, mtime, flags) from src to dst"""

    st = os.stat(src)

    mode = stat.S_IMODE(st.st_mode)

    if hasattr(os, 'utime'):

        os.utime(dst, (st.st_atime, st.st_mtime))

    if hasattr(os, 'chmod'):

        os.chmod(dst, mode)

    if hasattr(os, 'chflags') and hasattr(st, 'st_flags'):

        os.chflags(dst, st.st_flags)

def copy(src, dst):

    """Copy data and mode bits ("cp src dst").

    The destination may be a directory.

    """

    if os.path.isdir(dst):

        dst = os.path.join(dst, os.path.basename(src))

    copyfile(src, dst)

    copymode(src, dst)

def copy2(src, dst):

    """Copy data and all stat info ("cp -p src dst").

    The destination may be a directory.

    """

    if os.path.isdir(dst):

        dst = os.path.join(dst, os.path.basename(src))

    copyfile(src, dst)

    copystat(src, dst)

def ignore_patterns(*patterns):

    """Function that can be used as copytree() ignore parameter.

    Patterns is a sequence of glob-style patterns

    that are used to exclude files"""

    def _ignore_patterns(path, names):

        ignored_names = []

        for pattern in patterns:

            ignored_names.extend(fnmatch.filter(names, pattern))

        return set(ignored_names)

    return _ignore_patterns

def copytree(src, dst, symlinks=False, ignore=None):

    """Recursively copy a directory tree using copy2().

    The destination directory must not already exist.

    If exception(s) occur, an Error is raised with a list of reasons.

    If the optional symlinks flag is true, symbolic links in the

    source tree result in symbolic links in the destination tree; if

    it is false, the contents of the files pointed to by symbolic

    links are copied.

    The optional ignore argument is a callable. If given, it

    is called with the `src` parameter, which is the directory

    being visited by copytree(), and `names` which is the list of

    `src` contents, as returned by os.listdir():

        callable(src, names) -> ignored_names

    Since copytree() is called recursively, the callable will be

    called once for each directory that is copied. It returns a

    list of names relative to the `src` directory that should

    not be copied.

    XXX Consider this example code rather than the ultimate tool.

    """

    names = os.listdir(src)

    if ignore is not None:

        ignored_names = ignore(src, names)

    else:

        ignored_names = set()

    os.makedirs(dst)

    errors = []

    for name in names:

        if name in ignored_names:

            continue

        srcname = os.path.join(src, name)

        dstname = os.path.join(dst, name)

        try:

            if symlinks and os.path.islink(srcname):

                linkto = os.readlink(srcname)

                os.symlink(linkto, dstname)

            elif os.path.isdir(srcname):

                copytree(srcname, dstname, symlinks, ignore)

            else:

                copy2(srcname, dstname)

            # XXX What about devices, sockets etc.?

        except (IOError, os.error), why:

            errors.append((srcname, dstname, str(why)))

        # catch the Error from the recursive copytree so that we can

        # continue with other files

        except Error, err:

            errors.extend(err.args[0])

    try:

        copystat(src, dst)

    except OSError, why:

        if WindowsError is not None and isinstance(why, WindowsError):

            # Copying file access times may fail on Windows

            pass

        else:

            errors.extend((src, dst, str(why)))

    if errors:

        raise Error, errors

def rmtree(path, ignore_errors=False, onerror=None):

    """Recursively delete a directory tree.

    If ignore_errors is set, errors are ignored; otherwise, if onerror

    is set, it is called to handle the error with arguments (func,

    path, exc_info) where func is os.listdir, os.remove, or os.rmdir;

    path is the argument to that function that caused it to fail; and

    exc_info is a tuple returned by sys.exc_info().  If ignore_errors

    is false and onerror is None, an exception is raised.

    """

    if ignore_errors:

        def onerror(*args):

            pass

    elif onerror is None:

        def onerror(*args):

            raise

    try:

        if os.path.islink(path):

            # symlinks to directories are forbidden, see bug #1669

            raise OSError("Cannot call rmtree on a symbolic link")

    except OSError:

        onerror(os.path.islink, path, sys.exc_info())

        # can't continue even if onerror hook returns

        return

    names = []

    try:

        names = os.listdir(path)

    except os.error, err:

        onerror(os.listdir, path, sys.exc_info())

    for name in names:

        fullname = os.path.join(path, name)

        try:

            mode = os.lstat(fullname).st_mode

        except os.error:

            mode = 0

        if stat.S_ISDIR(mode):

            rmtree(fullname, ignore_errors, onerror)

        else:

            try:

                os.remove(fullname)

            except os.error, err:

                onerror(os.remove, fullname, sys.exc_info())

    try:

        os.rmdir(path)

    except os.error:

        onerror(os.rmdir, path, sys.exc_info())

def _basename(path):

    # A basename() variant which first strips the trailing slash, if present.

    # Thus we always get the last component of the path, even for directories.

    return os.path.basename(path.rstrip(os.path.sep))

def move(src, dst):

    """Recursively move a file or directory to another location. This is

    similar to the Unix "mv" command.

    If the destination is a directory or a symlink to a directory, the source

    is moved inside the directory. The destination path must not already

    exist.

    If the destination already exists but is not a directory, it may be

    overwritten depending on os.rename() semantics.

    If the destination is on our current filesystem, then rename() is used.

    Otherwise, src is copied to the destination and then removed.

    A lot more could be done here...  A look at a mv.c shows a lot of

    the issues this implementation glosses over.

    """

    real_dst = dst

    if os.path.isdir(dst):

        real_dst = os.path.join(dst, _basename(src))

        if os.path.exists(real_dst):

            raise Error, "Destination path '%s' already exists" % real_dst

    try:

        os.rename(src, real_dst)

    except OSError:

        if os.path.isdir(src):

            if destinsrc(src, dst):

                raise Error, "Cannot move a directory '%s' into itself '%s'." % (src, dst)

            copytree(src, real_dst, symlinks=True)

            rmtree(src)

        else:

            copy2(src, real_dst)

            os.unlink(src)

def destinsrc(src, dst):

    return abspath(dst).startswith(abspath(src))