plistlib.py

r"""plistlib.py -- a tool to generate and parse MacOSX .plist files.

The property list (.plist) file format is a simple XML pickle supporting
basic object types, like dictionaries, lists, numbers and strings.
Usually the top level object is a dictionary.

To write out a plist file, use the writePlist(rootObject, pathOrFile)
function. 'rootObject' is the top level object, 'pathOrFile' is a
filename or a (writable) file object.

To parse a plist from a file, use the readPlist(pathOrFile) function,
with a file name or a (readable) file object as the only argument. It
returns the top level object (again, usually a dictionary).

To work with plist data in bytes objects, you can use readPlistFromBytes()
and writePlistToBytes().

Values can be strings, integers, floats, booleans, tuples, lists,
dictionaries (but only with string keys), Data or datetime.datetime objects.
String values (including dictionary keys) have to be unicode strings -- they
will be written out as UTF-8.

The <data> plist type is supported through the Data class. This is a
thin wrapper around a Python bytes object. Use 'Data' if your strings
contain control characters.

Generate Plist example:

    pl = dict(
        aString = "Doodah",
        aList = ["A", "B", 12, 32.1, [1, 2, 3]],
        aFloat = 0.1,
        anInt = 728,
        aDict = dict(
            anotherString = "<hello & hi there!>",
            aUnicodeValue = "M\xe4ssig, Ma\xdf",
            aTrueValue = True,
            aFalseValue = False,
        ),
        someData = Data(b"<binary gunk>"),
        someMoreData = Data(b"<lots of binary gunk>" * 10),
        aDate = datetime.datetime.fromtimestamp(time.mktime(time.gmtime())),
    )
    writePlist(pl, fileName)

Parse Plist example:

    pl = readPlist(pathOrFile)
    print pl["aKey"]
"""


__all__ = [
    "readPlist", "writePlist", "readPlistFromBytes", "writePlistToBytes",
    "Plist", "Data", "Dict"
]
# Note: the Plist and Dict classes have been deprecated.

import binascii
import datetime
from io import BytesIO
import re


def readPlist(pathOrFile):
    """Read a .plist file. 'pathOrFile' may either be a file name or a
    (readable) file object. Return the unpacked root object (which
    usually is a dictionary).
    """
    didOpen = False
    try:
        if isinstance(pathOrFile, str):
            pathOrFile = open(pathOrFile, 'rb')
            didOpen = True
        p = PlistParser()
        rootObject = p.parse(pathOrFile)
    finally:
        if didOpen:
            pathOrFile.close()
    return rootObject


def writePlist(rootObject, pathOrFile):
    """Write 'rootObject' to a .plist file. 'pathOrFile' may either be a
    file name or a (writable) file object.
    """
    didOpen = False
    try:
        if isinstance(pathOrFile, str):
            pathOrFile = open(pathOrFile, 'wb')
            didOpen = True
        writer = PlistWriter(pathOrFile)
        writer.writeln("<plist version=\"1.0\">")
        writer.writeValue(rootObject)
        writer.writeln("</plist>")
    finally:
        if didOpen:
            pathOrFile.close()


def readPlistFromBytes(data):
    """Read a plist data from a bytes object. Return the root object.
    """
    return readPlist(BytesIO(data))


def writePlistToBytes(rootObject):
    """Return 'rootObject' as a plist-formatted bytes object.
    """
    f = BytesIO()
    writePlist(rootObject, f)
    return f.getvalue()


class DumbXMLWriter:
    def __init__(self, file, indentLevel=0, indent="\t"):
        self.file = file
        self.stack = []
        self.indentLevel = indentLevel
        self.indent = indent

    def beginElement(self, element):
        self.stack.append(element)
        self.writeln("<%s>" % element)
        self.indentLevel += 1

    def endElement(self, element):
        assert self.indentLevel > 0
        assert self.stack.pop() == element
        self.indentLevel -= 1
        self.writeln("</%s>" % element)

    def simpleElement(self, element, value=None):
        if value is not None:
            value = _escape(value)
            self.writeln("<%s>%s</%s>" % (element, value, element))
        else:
            self.writeln("<%s/>" % element)

    def writeln(self, line):
        if line:
            # plist has fixed encoding of utf-8
            if isinstance(line, str):
                line = line.encode('utf-8')
            self.file.write(self.indentLevel * self.indent)
            self.file.write(line)
        self.file.write(b'\n')


# Contents should conform to a subset of ISO 8601
# (in particular, YYYY '-' MM '-' DD 'T' HH ':' MM ':' SS 'Z'.  Smaller units may be omitted with
#  a loss of precision)
_dateParser = re.compile(r"(?P<year>\d\d\d\d)(?:-(?P<month>\d\d)(?:-(?P<day>\d\d)(?:T(?P<hour>\d\d)(?::(?P<minute>\d\d)(?::(?P<second>\d\d))?)?)?)?)?Z", re.ASCII)

def _dateFromString(s):
    order = ('year', 'month', 'day', 'hour', 'minute', 'second')
    gd = _dateParser.match(s).groupdict()
    lst = []
    for key in order:
        val = gd[key]
        if val is None:
            break
        lst.append(int(val))
    return datetime.datetime(*lst)

def _dateToString(d):
    return '%04d-%02d-%02dT%02d:%02d:%02dZ' % (
        d.year, d.month, d.day,
        d.hour, d.minute, d.second
    )


# Regex to find any control chars, except for \t \n and \r
_controlCharPat = re.compile(
    r"[\x00\x01\x02\x03\x04\x05\x06\x07\x08\x0b\x0c\x0e\x0f"
    r"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f]")

def _escape(text):
    m = _controlCharPat.search(text)
    if m is not None:
        raise ValueError("strings can't contains control characters; "
                         "use plistlib.Data instead")
    text = text.replace("\r\n", "\n")       # convert DOS line endings
    text = text.replace("\r", "\n")         # convert Mac line endings
    text = text.replace("&", "&amp;")       # escape '&'
    text = text.replace("<", "&lt;")        # escape '<'
    text = text.replace(">", "&gt;")        # escape '>'
    return text


PLISTHEADER = b"""\
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
"""

class PlistWriter(DumbXMLWriter):

    def __init__(self, file, indentLevel=0, indent=b"\t", writeHeader=1):
        if writeHeader:
            file.write(PLISTHEADER)
        DumbXMLWriter.__init__(self, file, indentLevel, indent)

    def writeValue(self, value):
        if isinstance(value, str):
            self.simpleElement("string", value)
        elif isinstance(value, bool):
            # must switch for bool before int, as bool is a
            # subclass of int...
            if value:
                self.simpleElement("true")
            else:
                self.simpleElement("false")
        elif isinstance(value, int):
            self.simpleElement("integer", "%d" % value)
        elif isinstance(value, float):
            self.simpleElement("real", repr(value))
        elif isinstance(value, dict):
            self.writeDict(value)
        elif isinstance(value, Data):
            self.writeData(value)
        elif isinstance(value, datetime.datetime):
            self.simpleElement("date", _dateToString(value))
        elif isinstance(value, (tuple, list)):
            self.writeArray(value)
        else:
            raise TypeError("unsupported type: %s" % type(value))

    def writeData(self, data):
        self.beginElement("data")
        self.indentLevel -= 1
        maxlinelength = max(16, 76 - len(self.indent.replace(b"\t", b" " * 8) *
                                 self.indentLevel))
        for line in data.asBase64(maxlinelength).split(b"\n"):
            if line:
                self.writeln(line)
        self.indentLevel += 1
        self.endElement("data")

    def writeDict(self, d):
        if d:
            self.beginElement("dict")
            items = sorted(d.items())
            for key, value in items:
                if not isinstance(key, str):
                    raise TypeError("keys must be strings")
                self.simpleElement("key", key)
                self.writeValue(value)
            self.endElement("dict")
        else:
            self.simpleElement("dict")

    def writeArray(self, array):
        if array:
            self.beginElement("array")
            for value in array:
                self.writeValue(value)
            self.endElement("array")
        else:
            self.simpleElement("array")


class _InternalDict(dict):

    # This class is needed while Dict is scheduled for deprecation:
    # we only need to warn when a *user* instantiates Dict or when
    # the "attribute notation for dict keys" is used.

    def __getattr__(self, attr):
        try:
            value = self[attr]
        except KeyError:
            raise AttributeError(attr)
        from warnings import warn
        warn("Attribute access from plist dicts is deprecated, use d[key] "
             "notation instead", DeprecationWarning, 2)
        return value

    def __setattr__(self, attr, value):
        from warnings import warn
        warn("Attribute access from plist dicts is deprecated, use d[key] "
             "notation instead", DeprecationWarning, 2)
        self[attr] = value

    def __delattr__(self, attr):
        try:
            del self[attr]
        except KeyError:
            raise AttributeError(attr)
        from warnings import warn
        warn("Attribute access from plist dicts is deprecated, use d[key] "
             "notation instead", DeprecationWarning, 2)

class Dict(_InternalDict):

    def __init__(self, **kwargs):
        from warnings import warn
        warn("The plistlib.Dict class is deprecated, use builtin dict instead",
             DeprecationWarning, 2)
        super().__init__(**kwargs)


class Plist(_InternalDict):

    """This class has been deprecated. Use readPlist() and writePlist()
    functions instead, together with regular dict objects.
    """

    def __init__(self, **kwargs):
        from warnings import warn
        warn("The Plist class is deprecated, use the readPlist() and "
             "writePlist() functions instead", DeprecationWarning, 2)
        super().__init__(**kwargs)

    def fromFile(cls, pathOrFile):
        """Deprecated. Use the readPlist() function instead."""
        rootObject = readPlist(pathOrFile)
        plist = cls()
        plist.update(rootObject)
        return plist
    fromFile = classmethod(fromFile)

    def write(self, pathOrFile):
        """Deprecated. Use the writePlist() function instead."""
        writePlist(self, pathOrFile)


def _encodeBase64(s, maxlinelength=76):
    # copied from base64.encodebytes(), with added maxlinelength argument
    maxbinsize = (maxlinelength//4)*3
    pieces = []
    for i in range(0, len(s), maxbinsize):
        chunk = s[i : i + maxbinsize]
        pieces.append(binascii.b2a_base64(chunk))
    return b''.join(pieces)

class Data:

    """Wrapper for binary data."""

    def __init__(self, data):
        if not isinstance(data, bytes):
            raise TypeError("data must be as bytes")
        self.data = data

    @classmethod
    def fromBase64(cls, data):
        # base64.decodebytes just calls binascii.a2b_base64;
        # it seems overkill to use both base64 and binascii.
        return cls(binascii.a2b_base64(data))

    def asBase64(self, maxlinelength=76):
        return _encodeBase64(self.data, maxlinelength)

    def __eq__(self, other):
        if isinstance(other, self.__class__):
            return self.data == other.data
        elif isinstance(other, str):
            return self.data == other
        else:
            return id(self) == id(other)

    def __repr__(self):
        return "%s(%s)" % (self.__class__.__name__, repr(self.data))

class PlistParser:

    def __init__(self):
        self.stack = []
        self.currentKey = None
        self.root = None

    def parse(self, fileobj):
        from xml.parsers.expat import ParserCreate
        self.parser = ParserCreate()
        self.parser.StartElementHandler = self.handleBeginElement
        self.parser.EndElementHandler = self.handleEndElement
        self.parser.CharacterDataHandler = self.handleData
        self.parser.ParseFile(fileobj)
        return self.root

    def handleBeginElement(self, element, attrs):
        self.data = []
        handler = getattr(self, "begin_" + element, None)
        if handler is not None:
            handler(attrs)

    def handleEndElement(self, element):
        handler = getattr(self, "end_" + element, None)
        if handler is not None:
            handler()

    def handleData(self, data):
        self.data.append(data)

    def addObject(self, value):
        if self.currentKey is not None:
            if not isinstance(self.stack[-1], type({})):
                raise ValueError("unexpected element at line %d" %
                                 self.parser.CurrentLineNumber)
            self.stack[-1][self.currentKey] = value
            self.currentKey = None
        elif not self.stack:
            # this is the root object
            self.root = value
        else:
            if not isinstance(self.stack[-1], type([])):
                raise ValueError("unexpected element at line %d" %
                                 self.parser.CurrentLineNumber)
            self.stack[-1].append(value)

    def getData(self):
        data = ''.join(self.data)
        self.data = []
        return data

    # element handlers

    def begin_dict(self, attrs):
        d = _InternalDict()
        self.addObject(d)
        self.stack.append(d)
    def end_dict(self):
        if self.currentKey:
            raise ValueError("missing value for key '%s' at line %d" %
                             (self.currentKey,self.parser.CurrentLineNumber))
        self.stack.pop()

    def end_key(self):
        if self.currentKey or not isinstance(self.stack[-1], type({})):
            raise ValueError("unexpected key at line %d" %
                             self.parser.CurrentLineNumber)
        self.currentKey = self.getData()

    def begin_array(self, attrs):
        a = []
        self.addObject(a)
        self.stack.append(a)
    def end_array(self):
        self.stack.pop()

    def end_true(self):
        self.addObject(True)
    def end_false(self):
        self.addObject(False)
    def end_integer(self):
        self.addObject(int(self.getData()))
    def end_real(self):
        self.addObject(float(self.getData()))
    def end_string(self):
        self.addObject(self.getData())
    def end_data(self):
        self.addObject(Data.fromBase64(self.getData().encode("utf-8")))
    def end_date(self):
        self.addObject(_dateFromString(self.getData()))