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1"""Simple API for XML (SAX) implementation for Python.
2
3This module provides an implementation of the SAX 2 interface;
4information about the Java version of the interface can be found at
5http://www.megginson.com/SAX/.  The Python version of the interface is
6documented at <...>.
7
8This package contains the following modules:
9
10handler -- Base classes and constants which define the SAX 2 API for
11           the 'client-side' of SAX for Python.
12
13saxutils -- Implementation of the convenience classes commonly used to
14            work with SAX.
15
16xmlreader -- Base classes and constants which define the SAX 2 API for
17             the parsers used with SAX for Python.
18
19expatreader -- Driver that allows use of the Expat parser with SAX.
20"""
21
22from .xmlreader import InputSource
23from .handler import ContentHandler, ErrorHandler
24from ._exceptions import SAXException, SAXNotRecognizedException, \
25                        SAXParseException, SAXNotSupportedException, \
26                        SAXReaderNotAvailable
27
28
29def parse(source, handler, errorHandler=ErrorHandler()):
30    parser = make_parser()
31    parser.setContentHandler(handler)
32    parser.setErrorHandler(errorHandler)
33    parser.parse(source)
34
35def parseString(string, handler, errorHandler=ErrorHandler()):
36    import io
37    if errorHandler is None:
38        errorHandler = ErrorHandler()
39    parser = make_parser()
40    parser.setContentHandler(handler)
41    parser.setErrorHandler(errorHandler)
42
43    inpsrc = InputSource()
44    if isinstance(string, str):
45        inpsrc.setCharacterStream(io.StringIO(string))
46    else:
47        inpsrc.setByteStream(io.BytesIO(string))
48    parser.parse(inpsrc)
49
50# this is the parser list used by the make_parser function if no
51# alternatives are given as parameters to the function
52
53default_parser_list = ["xml.sax.expatreader"]
54
55# tell modulefinder that importing sax potentially imports expatreader
56_false = 0
57if _false:
58    import xml.sax.expatreader
59
60import os, sys
61if not sys.flags.ignore_environment and "PY_SAX_PARSER" in os.environ:
62    default_parser_list = os.environ["PY_SAX_PARSER"].split(",")
63del os, sys
64
65
66def make_parser(parser_list=()):
67    """Creates and returns a SAX parser.
68
69    Creates the first parser it is able to instantiate of the ones
70    given in the iterable created by chaining parser_list and
71    default_parser_list.  The iterables must contain the names of Python
72    modules containing both a SAX parser and a create_parser function."""
73
74    for parser_name in list(parser_list) + default_parser_list:
75        try:
76            return _create_parser(parser_name)
77        except ImportError:
78            import sys
79            if parser_name in sys.modules:
80                # The parser module was found, but importing it
81                # failed unexpectedly, pass this exception through
82                raise
83        except SAXReaderNotAvailable:
84            # The parser module detected that it won't work properly,
85            # so try the next one
86            pass
87
88    raise SAXReaderNotAvailable("No parsers found", None)
89
90# --- Internal utility methods used by make_parser
91
92def _create_parser(parser_name):
93    drv_module = __import__(parser_name,{},{},['create_parser'])
94    return drv_module.create_parser()
95