"""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

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

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

class Error(EnvironmentError):

    pass

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 and mtime) 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)

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 copytree(src, dst, symlinks=False):

    """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.

    XXX Consider this example code rather than the ultimate tool.

    """

    names = os.listdir(src)

    os.makedirs(dst)

    errors = []

    for name in names:

        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)

            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 WindowsError:

        # can't copy file access times on Windows

        pass

    except OSError, why:

        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

    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 move(src, dst):

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

    If the destination is on our current filesystem, then simply use

    rename.  Otherwise, copy src to the dst and then remove src.

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

    the issues this implementation glosses over.

    """

    try:

        os.rename(src, 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, dst, symlinks=True)

            rmtree(src)

        else:

            copy2(src,dst)

            os.unlink(src)

def destinsrc(src, dst):

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