"""distutils.util

Miscellaneous utility functions -- anything that doesn't fit into
one of the other *util.py modules.
"""

__revision__ = "$Id$"

import sys, os, string, re
from distutils.errors import DistutilsPlatformError
from distutils.dep_util import newer
from distutils.spawn import spawn
from distutils import log
from distutils.errors import DistutilsByteCompileError

def get_platform ():
    """Return a string that identifies the current platform.  This is used
    mainly to distinguish platform-specific build directories and
    platform-specific built distributions.  Typically includes the OS name
    and version and the architecture (as supplied by 'os.uname()'),
    although the exact information included depends on the OS; eg. for IRIX
    the architecture isn't particularly important (IRIX only runs on SGI
    hardware), but for Linux the kernel version isn't particularly
    important.

    Examples of returned values:
       linux-i586
       linux-alpha (?)
       solaris-2.6-sun4u
       irix-5.3
       irix64-6.2

    Windows will return one of:
       win-amd64 (64bit Windows on AMD64 (aka x86_64, Intel64, EM64T, etc)
       win-ia64 (64bit Windows on Itanium)
       win32 (all others - specifically, sys.platform is returned)

    For other non-POSIX platforms, currently just returns 'sys.platform'.
    """
    if os.name == 'nt':
        # sniff sys.version for architecture.
        prefix = " bit ("
        i = string.find(sys.version, prefix)
        if i == -1:
            return sys.platform
        j = string.find(sys.version, ")", i)
        look = sys.version[i+len(prefix):j].lower()
        if look=='amd64':
            return 'win-amd64'
        if look=='itanium':
            return 'win-ia64'
        return sys.platform

    # Set for cross builds explicitly
    if "_PYTHON_HOST_PLATFORM" in os.environ:
        return os.environ["_PYTHON_HOST_PLATFORM"]

    if os.name != "posix" or not hasattr(os, 'uname'):
        # XXX what about the architecture? NT is Intel or Alpha,
        # Mac OS is M68k or PPC, etc.
        return sys.platform

    # Try to distinguish various flavours of Unix

    (osname, host, release, version, machine) = os.uname()

    # Convert the OS name to lowercase, remove '/' characters
    # (to accommodate BSD/OS), and translate spaces (for "Power Macintosh")
    osname = string.lower(osname)
    osname = string.replace(osname, '/', '')
    machine = string.replace(machine, ' ', '_')
    machine = string.replace(machine, '/', '-')

    if osname[:5] == "linux":
        # At least on Linux/Intel, 'machine' is the processor --
        # i386, etc.
        # XXX what about Alpha, SPARC, etc?
        return  "%s-%s" % (osname, machine)
    elif osname[:5] == "sunos":
        if release[0] >= "5":           # SunOS 5 == Solaris 2
            osname = "solaris"
            release = "%d.%s" % (int(release[0]) - 3, release[2:])
            # We can't use "platform.architecture()[0]" because a
            # bootstrap problem. We use a dict to get an error
            # if some suspicious happens.
            bitness = {2147483647:"32bit", 9223372036854775807:"64bit"}
            machine += ".%s" % bitness[sys.maxint]
        # fall through to standard osname-release-machine representation
    elif osname[:4] == "irix":              # could be "irix64"!
        return "%s-%s" % (osname, release)
    elif osname[:3] == "aix":
        return "%s-%s.%s" % (osname, version, release)
    elif osname[:6] == "cygwin":
        osname = "cygwin"
        rel_re = re.compile (r'[\d.]+')
        m = rel_re.match(release)
        if m:
            release = m.group()
    elif osname[:6] == "darwin":
        import _osx_support, distutils.sysconfig
        osname, release, machine = _osx_support.get_platform_osx(
                                        distutils.sysconfig.get_config_vars(),
                                        osname, release, machine)

    return "%s-%s-%s" % (osname, release, machine)

# get_platform ()


def convert_path (pathname):
    """Return 'pathname' as a name that will work on the native filesystem,
    i.e. split it on '/' and put it back together again using the current
    directory separator.  Needed because filenames in the setup script are
    always supplied in Unix style, and have to be converted to the local
    convention before we can actually use them in the filesystem.  Raises
    ValueError on non-Unix-ish systems if 'pathname' either starts or
    ends with a slash.
    """
    if os.sep == '/':
        return pathname
    if not pathname:
        return pathname
    if pathname[0] == '/':
        raise ValueError, "path '%s' cannot be absolute" % pathname
    if pathname[-1] == '/':
        raise ValueError, "path '%s' cannot end with '/'" % pathname

    paths = string.split(pathname, '/')
    while '.' in paths:
        paths.remove('.')
    if not paths:
        return os.curdir
    return os.path.join(*paths)

# convert_path ()


def change_root (new_root, pathname):
    """Return 'pathname' with 'new_root' prepended.  If 'pathname' is
    relative, this is equivalent to "os.path.join(new_root,pathname)".
    Otherwise, it requires making 'pathname' relative and then joining the
    two, which is tricky on DOS/Windows and Mac OS.
    """
    if os.name == 'posix':
        if not os.path.isabs(pathname):
            return os.path.join(new_root, pathname)
        else:
            return os.path.join(new_root, pathname[1:])

    elif os.name == 'nt':
        (drive, path) = os.path.splitdrive(pathname)
        if path[0] == '\\':
            path = path[1:]
        return os.path.join(new_root, path)

    elif os.name == 'os2':
        (drive, path) = os.path.splitdrive(pathname)
        if path[0] == os.sep:
            path = path[1:]
        return os.path.join(new_root, path)

    else:
        raise DistutilsPlatformError, \
              "nothing known about platform '%s'" % os.name


_environ_checked = 0
def check_environ ():
    """Ensure that 'os.environ' has all the environment variables we
    guarantee that users can use in config files, command-line options,
    etc.  Currently this includes:
      HOME - user's home directory (Unix only)
      PLAT - description of the current platform, including hardware
             and OS (see 'get_platform()')
    """
    global _environ_checked
    if _environ_checked:
        return

    if os.name == 'posix' and 'HOME' not in os.environ:
        import pwd
        os.environ['HOME'] = pwd.getpwuid(os.getuid())[5]

    if 'PLAT' not in os.environ:
        os.environ['PLAT'] = get_platform()

    _environ_checked = 1


def subst_vars (s, local_vars):
    """Perform shell/Perl-style variable substitution on 'string'.  Every
    occurrence of '$' followed by a name is considered a variable, and
    variable is substituted by the value found in the 'local_vars'
    dictionary, or in 'os.environ' if it's not in 'local_vars'.
    'os.environ' is first checked/augmented to guarantee that it contains
    certain values: see 'check_environ()'.  Raise ValueError for any
    variables not found in either 'local_vars' or 'os.environ'.
    """
    check_environ()
    def _subst (match, local_vars=local_vars):
        var_name = match.group(1)
        if var_name in local_vars:
            return str(local_vars[var_name])
        else:
            return os.environ[var_name]

    try:
        return re.sub(r'\$([a-zA-Z_][a-zA-Z_0-9]*)', _subst, s)
    except KeyError, var:
        raise ValueError, "invalid variable '$%s'" % var

# subst_vars ()


def grok_environment_error (exc, prefix="error: "):
    # Function kept for backward compatibility.
    # Used to try clever things with EnvironmentErrors,
    # but nowadays str(exception) produces good messages.
    return prefix + str(exc)


# Needed by 'split_quoted()'
_wordchars_re = _squote_re = _dquote_re = None
def _init_regex():
    global _wordchars_re, _squote_re, _dquote_re
    _wordchars_re = re.compile(r'[^\\\'\"%s ]*' % string.whitespace)
    _squote_re = re.compile(r"'(?:[^'\\]|\\.)*'")
    _dquote_re = re.compile(r'"(?:[^"\\]|\\.)*"')

def split_quoted (s):
    """Split a string up according to Unix shell-like rules for quotes and
    backslashes.  In short: words are delimited by spaces, as long as those
    spaces are not escaped by a backslash, or inside a quoted string.
    Single and double quotes are equivalent, and the quote characters can
    be backslash-escaped.  The backslash is stripped from any two-character
    escape sequence, leaving only the escaped character.  The quote
    characters are stripped from any quoted string.  Returns a list of
    words.
    """

    # This is a nice algorithm for splitting up a single string, since it
    # doesn't require character-by-character examination.  It was a little
    # bit of a brain-bender to get it working right, though...
    if _wordchars_re is None: _init_regex()

    s = string.strip(s)
    words = []
    pos = 0

    while s:
        m = _wordchars_re.match(s, pos)
        end = m.end()
        if end == len(s):
            words.append(s[:end])
            break

        if s[end] in string.whitespace: # unescaped, unquoted whitespace: now
            words.append(s[:end])       # we definitely have a word delimiter
            s = string.lstrip(s[end:])
            pos = 0

        elif s[end] == '\\':            # preserve whatever is being escaped;
                                        # will become part of the current word
            s = s[:end] + s[end+1:]
            pos = end+1

        else:
            if s[end] == "'":           # slurp singly-quoted string
                m = _squote_re.match(s, end)
            elif s[end] == '"':         # slurp doubly-quoted string
                m = _dquote_re.match(s, end)
            else:
                raise RuntimeError, \
                      "this can't happen (bad char '%c')" % s[end]

            if m is None:
                raise ValueError, \
                      "bad string (mismatched %s quotes?)" % s[end]

            (beg, end) = m.span()
            s = s[:beg] + s[beg+1:end-1] + s[end:]
            pos = m.end() - 2

        if pos >= len(s):
            words.append(s)
            break

    return words

# split_quoted ()


def execute (func, args, msg=None, verbose=0, dry_run=0):
    """Perform some action that affects the outside world (eg.  by
    writing to the filesystem).  Such actions are special because they
    are disabled by the 'dry_run' flag.  This method takes care of all
    that bureaucracy for you; all you have to do is supply the
    function to call and an argument tuple for it (to embody the
    "external action" being performed), and an optional message to
    print.
    """
    if msg is None:
        msg = "%s%r" % (func.__name__, args)