about summary refs log tree commit diff stats
path: root/subx/030---operands.cc
diff options
context:
space:
mode:
Diffstat (limited to 'subx/030---operands.cc')
0 files changed, 0 insertions, 0 deletions
68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322
# This file was taken from the python standard library and has been
# slightly modified to do a "yield" after every 16KB of copying
"""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", "copystat", "copy2", "BLOCK_SIZE",
           "copytree", "move", "rmtree", "Error", "SpecialFileError"]

APPENDIX = '_'
BLOCK_SIZE = 16 * 1024


class Error(EnvironmentError):
    pass


class SpecialFileError(EnvironmentError):
    """Raised when trying to do a kind of operation (e.g. copying) which is
    not supported on a special file (e.g. a named pipe)"""

try:
    WindowsError
except NameError:
    WindowsError = None


def copyfileobj(fsrc, fdst, length=BLOCK_SIZE):
    """copy data from file-like object fsrc to file-like object fdst"""
    done = 0
    while 1:
        buf = fsrc.read(length)
        if not buf:
            break
        fdst.write(buf)
        done += len(buf)
        yield done


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(abspath(src)) ==
            os.path.normcase(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
    for fn in [src, dst]:
        try:
            st = os.stat(fn)
        except OSError:
            # File most likely does not exist
            pass
        else:
            # XXX What about other special files? (sockets, devices...)
            if stat.S_ISFIFO(st.st_mode):
                raise SpecialFileError("`%s` is a named pipe" % fn)
    try:
        fsrc = open(src, 'rb')
        fdst = open(dst, 'wb')
        for done in copyfileobj(fsrc, fdst):
            yield done
    finally:
        if fdst:
            fdst.close()
        if fsrc:
            fsrc.close()


def copystat(src, dst):
    """Copy all stat info (mode bits, atime, mtime, flags) from src to dst"""
    st = os.lstat(src)
    mode = stat.S_IMODE(st.st_mode)
    if hasattr(os, 'utime'):
        try: os.utime(dst, (st.st_atime, st.st_mtime))
        except: pass
    if hasattr(os, 'chmod'):
        try: os.chmod(dst, mode)
        except: pass
    if hasattr(os, 'chflags') and hasattr(st, 'st_flags'):
        try: os.chflags(dst, st.st_flags)
        except: pass


def copy2(src, dst, overwrite=False, symlinks=False):
    """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))
    if not overwrite:
        dst = get_safe_path(dst)
    if symlinks and os.path.islink(src):
        linkto = os.readlink(src)
        if overwrite and os.path.lexists(dst):
            os.unlink(dst)
        os.symlink(linkto, dst)
    else:
        for done in copyfile(src, dst):
            yield done
        copystat(src, dst)


def get_safe_path(dst):
    if not os.path.exists(dst):
        return dst
    if not dst.endswith(APPENDIX):
        dst += APPENDIX
        if not os.path.exists(dst):
            return dst
    n = 0
    test_dst = dst + str(n)
    while os.path.exists(test_dst):
        n += 1
        test_dst = dst + str(n)

    return test_dst


def copytree(src, dst, symlinks=False, ignore=None, overwrite=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.

    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()

    errors = []
    try:
        os.makedirs(dst)
    except Exception as err:
        if not overwrite:
            dst = get_safe_path(dst)
            os.makedirs(dst)
    done = 0
    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)
                if overwrite and os.path.lexists(dstname):
                    os.unlink(dstname)
                os.symlink(linkto, dstname)
                copystat(srcname, dstname)
            elif os.path.isdir(srcname):
                d = 0
                for d in copytree(srcname, dstname, symlinks,
                        ignore, overwrite):
                    yield done + d
                done += d
            else:
                # Will raise a SpecialFileError for unsupported file types
                d = 0
                for d in copy2(srcname, dstname,
                        overwrite=overwrite, symlinks=symlinks):
                    yield done + d
                done += d
        # catch the Error from the recursive copytree so that we can
        # continue with other files
        except Error as err:
            errors.extend(err.args[0])
        except EnvironmentError as why:
            errors.append((srcname, dstname, str(why)))
    try:
        copystat(src, dst)
    except OSError as 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 as 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 as 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, overwrite=False):
    """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 = os.path.join(dst, _basename(src))
    if not overwrite:
        real_dst = get_safe_path(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))
            for done in copytree(src, real_dst, symlinks=True, overwrite=overwrite):
                yield done
            rmtree(src)
        else:
            for done in copy2(src, real_dst, symlinks=True, overwrite=overwrite):
                yield done
            os.unlink(src)


def _destinsrc(src, dst):
    src = abspath(src)
    dst = abspath(dst)
    if not src.endswith(os.path.sep):
        src += os.path.sep
    if not dst.endswith(os.path.sep):
        dst += os.path.sep
    return dst.startswith(src)

# vi: expandtab sts=4 ts=4 sw=4