Merged revisions 62734,62736,62748,62769 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r62734 | brett.cannon | 2008-05-05 22:21:38 +0200 (Mon, 05 May 2008) | 5 lines

  Add the 'json' package. Code taken from simplejson 1.9 and contributed by Bob
  Ippolito.

  Closes issue #2750.
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  r62736 | georg.brandl | 2008-05-05 22:53:39 +0200 (Mon, 05 May 2008) | 2 lines

  Fix JSON module docs.
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  r62748 | benjamin.peterson | 2008-05-06 04:51:10 +0200 (Tue, 06 May 2008) | 2 lines

  PEP 8 nits in json package
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  r62769 | christian.heimes | 2008-05-06 18:18:41 +0200 (Tue, 06 May 2008) | 2 lines

  Intern static string
  Use float constructors instead of magic code for float constants
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1 files changed, 384 insertions, 0 deletions

diff --git a/Lib/json/encoder.py b/Lib/json/encoder.py
new file mode 100644
index 0000000000..4cb366016f
--- /dev/null
+++ b/Lib/json/encoder.py
@@ -0,0 +1,384 @@
+"""Implementation of JSONEncoder
+"""
+
+import re
+
+try:
+    from _json import encode_basestring_ascii as c_encode_basestring_ascii
+except ImportError:
+    c_encode_basestring_ascii = None
+
+__all__ = ['JSONEncoder']
+
+ESCAPE = re.compile(r'[\x00-\x1f\\"\b\f\n\r\t]')
+ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')
+HAS_UTF8 = re.compile(r'[\x80-\xff]')
+ESCAPE_DCT = {
+    '\\': '\\\\',
+    '"': '\\"',
+    '\b': '\\b',
+    '\f': '\\f',
+    '\n': '\\n',
+    '\r': '\\r',
+    '\t': '\\t',
+}
+for i in range(0x20):
+    ESCAPE_DCT.setdefault(chr(i), '\\u{0:04x}'.format(i))
+
+# Assume this produces an infinity on all machines (probably not guaranteed)
+INFINITY = float('1e66666')
+FLOAT_REPR = repr
+
+def floatstr(o, allow_nan=True):
+    # Check for specials.  Note that this type of test is processor- and/or
+    # platform-specific, so do tests which don't depend on the internals.
+
+    if o != o:
+        text = 'NaN'
+    elif o == INFINITY:
+        text = 'Infinity'
+    elif o == -INFINITY:
+        text = '-Infinity'
+    else:
+        return FLOAT_REPR(o)
+
+    if not allow_nan:
+        msg = "Out of range float values are not JSON compliant: " + repr(o)
+        raise ValueError(msg)
+
+    return text
+
+
+def encode_basestring(s):
+    """Return a JSON representation of a Python string
+
+    """
+    def replace(match):
+        return ESCAPE_DCT[match.group(0)]
+    return '"' + ESCAPE.sub(replace, s) + '"'
+
+
+def py_encode_basestring_ascii(s):
+    if isinstance(s, bytes): # and HAS_UTF8.search(s) is not None:
+        s = s.decode('utf-8')
+    def replace(match):
+        s = match.group(0)
+        try:
+            return ESCAPE_DCT[s]
+        except KeyError:
+            n = ord(s)
+            if n < 0x10000:
+                return '\\u{0:04x}'.format(n)
+            else:
+                # surrogate pair
+                n -= 0x10000
+                s1 = 0xd800 | ((n >> 10) & 0x3ff)
+                s2 = 0xdc00 | (n & 0x3ff)
+                return '\\u{0:04x}\\u{1:04x}'.format(s1, s2)
+    return '"' + (ESCAPE_ASCII.sub(replace, s)) + '"'
+
+
+if c_encode_basestring_ascii is not None:
+    encode_basestring_ascii = c_encode_basestring_ascii
+else:
+    encode_basestring_ascii = py_encode_basestring_ascii
+
+
+class JSONEncoder(object):
+    """Extensible JSON <http://json.org> encoder for Python data structures.
+
+    Supports the following objects and types by default:
+
+    +-------------------+---------------+
+    | Python            | JSON          |
+    +===================+===============+
+    | dict              | object        |
+    +-------------------+---------------+
+    | list, tuple       | array         |
+    +-------------------+---------------+
+    | str, unicode      | string        |
+    +-------------------+---------------+
+    | int, long, float  | number        |
+    +-------------------+---------------+
+    | True              | true          |
+    +-------------------+---------------+
+    | False             | false         |
+    +-------------------+---------------+
+    | None              | null          |
+    +-------------------+---------------+
+
+    To extend this to recognize other objects, subclass and implement a
+    ``.default()`` method with another method that returns a serializable
+    object for ``o`` if possible, otherwise it should call the superclass
+    implementation (to raise ``TypeError``).
+
+    """
+    __all__ = ['__init__', 'default', 'encode', 'iterencode']
+    item_separator = ', '
+    key_separator = ': '
+    def __init__(self, skipkeys=False, ensure_ascii=True,
+            check_circular=True, allow_nan=True, sort_keys=False,
+            indent=None, separators=None, encoding='utf-8', default=None):
+        """Constructor for JSONEncoder, with sensible defaults.
+
+        If skipkeys is False, then it is a TypeError to attempt
+        encoding of keys that are not str, int, long, float or None.  If
+        skipkeys is True, such items are simply skipped.
+
+        If ensure_ascii is True, the output is guaranteed to be str
+        objects with all incoming unicode characters escaped.  If
+        ensure_ascii is false, the output will be unicode object.
+
+        If check_circular is True, then lists, dicts, and custom encoded
+        objects will be checked for circular references during encoding to
+        prevent an infinite recursion (which would cause an OverflowError).
+        Otherwise, no such check takes place.
+
+        If allow_nan is True, then NaN, Infinity, and -Infinity will be
+        encoded as such.  This behavior is not JSON specification compliant,
+        but is consistent with most JavaScript based encoders and decoders.
+        Otherwise, it will be a ValueError to encode such floats.
+
+        If sort_keys is True, then the output of dictionaries will be
+        sorted by key; this is useful for regression tests to ensure
+        that JSON serializations can be compared on a day-to-day basis.
+
+        If indent is a non-negative integer, then JSON array
+        elements and object members will be pretty-printed with that
+        indent level.  An indent level of 0 will only insert newlines.
+        None is the most compact representation.
+
+        If specified, separators should be a (item_separator, key_separator)
+        tuple.  The default is (', ', ': ').  To get the most compact JSON
+        representation you should specify (',', ':') to eliminate whitespace.
+
+        If specified, default is a function that gets called for objects
+        that can't otherwise be serialized.  It should return a JSON encodable
+        version of the object or raise a ``TypeError``.
+
+        If encoding is not None, then all input strings will be
+        transformed into unicode using that encoding prior to JSON-encoding.
+        The default is UTF-8.
+
+        """
+        self.skipkeys = skipkeys
+        self.ensure_ascii = ensure_ascii
+        self.check_circular = check_circular
+        self.allow_nan = allow_nan
+        self.sort_keys = sort_keys
+        self.indent = indent
+        self.current_indent_level = 0
+        if separators is not None:
+            self.item_separator, self.key_separator = separators
+        if default is not None:
+            self.default = default
+        self.encoding = encoding
+
+    def _newline_indent(self):
+        return '\n' + (' ' * (self.indent * self.current_indent_level))
+
+    def _iterencode_list(self, lst, markers=None):
+        if not lst:
+            yield '[]'
+            return
+        if markers is not None:
+            markerid = id(lst)
+            if markerid in markers:
+                raise ValueError("Circular reference detected")
+            markers[markerid] = lst
+        yield '['
+        if self.indent is not None:
+            self.current_indent_level += 1
+            newline_indent = self._newline_indent()
+            separator = self.item_separator + newline_indent
+            yield newline_indent
+        else:
+            newline_indent = None
+            separator = self.item_separator
+        first = True
+        for value in lst:
+            if first:
+                first = False
+            else:
+                yield separator
+            for chunk in self._iterencode(value, markers):
+                yield chunk
+        if newline_indent is not None:
+            self.current_indent_level -= 1
+            yield self._newline_indent()
+        yield ']'
+        if markers is not None:
+            del markers[markerid]
+
+    def _iterencode_dict(self, dct, markers=None):
+        if not dct:
+            yield '{}'
+            return
+        if markers is not None:
+            markerid = id(dct)
+            if markerid in markers:
+                raise ValueError("Circular reference detected")
+            markers[markerid] = dct
+        yield '{'
+        key_separator = self.key_separator
+        if self.indent is not None:
+            self.current_indent_level += 1
+            newline_indent = self._newline_indent()
+            item_separator = self.item_separator + newline_indent
+            yield newline_indent
+        else:
+            newline_indent = None
+            item_separator = self.item_separator
+        first = True
+        if self.ensure_ascii:
+            encoder = encode_basestring_ascii
+        else:
+            encoder = encode_basestring
+        allow_nan = self.allow_nan
+        if self.sort_keys:
+            keys = list(dct.keys())
+            keys.sort()
+            items = [(k, dct[k]) for k in keys]
+        else:
+            items = iter(dct.items())
+        _encoding = self.encoding
+        _do_decode = (_encoding is not None
+            and not (_encoding == 'utf-8'))
+        for key, value in items:
+            if isinstance(key, str):
+                if _do_decode:
+                    key = key.decode(_encoding)
+            elif isinstance(key, str):
+                pass
+            # JavaScript is weakly typed for these, so it makes sense to
+            # also allow them.  Many encoders seem to do something like this.
+            elif isinstance(key, float):
+                key = floatstr(key, allow_nan)
+            elif isinstance(key, (int, int)):
+                key = str(key)
+            elif key is True:
+                key = 'true'
+            elif key is False:
+                key = 'false'
+            elif key is None:
+                key = 'null'
+            elif self.skipkeys:
+                continue
+            else:
+                raise TypeError("key {0!r} is not a string".format(key))
+            if first:
+                first = False
+            else:
+                yield item_separator
+            yield encoder(key)
+            yield key_separator
+            for chunk in self._iterencode(value, markers):
+                yield chunk
+        if newline_indent is not None:
+            self.current_indent_level -= 1
+            yield self._newline_indent()
+        yield '}'
+        if markers is not None:
+            del markers[markerid]
+
+    def _iterencode(self, o, markers=None):
+        if isinstance(o, str):
+            if self.ensure_ascii:
+                encoder = encode_basestring_ascii
+            else:
+                encoder = encode_basestring
+            _encoding = self.encoding
+            if (_encoding is not None and isinstance(o, str)
+                    and not (_encoding == 'utf-8')):
+                o = o.decode(_encoding)
+            yield encoder(o)
+        elif o is None:
+            yield 'null'
+        elif o is True:
+            yield 'true'
+        elif o is False:
+            yield 'false'
+        elif isinstance(o, (int, int)):
+            yield str(o)
+        elif isinstance(o, float):
+            yield floatstr(o, self.allow_nan)
+        elif isinstance(o, (list, tuple)):
+            for chunk in self._iterencode_list(o, markers):
+                yield chunk
+        elif isinstance(o, dict):
+            for chunk in self._iterencode_dict(o, markers):
+                yield chunk
+        else:
+            if markers is not None:
+                markerid = id(o)
+                if markerid in markers:
+                    raise ValueError("Circular reference detected")
+                markers[markerid] = o
+            for chunk in self._iterencode_default(o, markers):
+                yield chunk
+            if markers is not None:
+                del markers[markerid]
+
+    def _iterencode_default(self, o, markers=None):
+        newobj = self.default(o)
+        return self._iterencode(newobj, markers)
+
+    def default(self, o):
+        """Implement this method in a subclass such that it returns a serializable
+        object for ``o``, or calls the base implementation (to raise a
+        ``TypeError``).
+
+        For example, to support arbitrary iterators, you could implement
+        default like this::
+
+            def default(self, o):
+                try:
+                    iterable = iter(o)
+                except TypeError:
+                    pass
+                else:
+                    return list(iterable)
+                return JSONEncoder.default(self, o)
+
+        """
+        raise TypeError(repr(o) + " is not JSON serializable")
+
+    def encode(self, o):
+        """Return a JSON string representation of a Python data structure.
+
+        >>> JSONEncoder().encode({"foo": ["bar", "baz"]})
+        '{"foo": ["bar", "baz"]}'
+
+        """
+        # This is for extremely simple cases and benchmarks.
+        if isinstance(o, (str, bytes)):
+            if isinstance(o, bytes):
+                _encoding = self.encoding
+                if (_encoding is not None
+                        and not (_encoding == 'utf-8')):
+                    o = o.decode(_encoding)
+            if self.ensure_ascii:
+                return encode_basestring_ascii(o)
+            else:
+                return encode_basestring(o)
+        # This doesn't pass the iterator directly to ''.join() because the
+        # exceptions aren't as detailed.  The list call should be roughly
+        # equivalent to the PySequence_Fast that ''.join() would do.
+        chunks = list(self.iterencode(o))
+        return ''.join(chunks)
+
+    def iterencode(self, o):
+        """Encode the given object and yield each string representation as
+        available.
+
+        For example::
+
+            for chunk in JSONEncoder().iterencode(bigobject):
+                mysocket.write(chunk)
+
+        """
+        if self.check_circular:
+            markers = {}
+        else:
+            markers = None
+        return self._iterencode(o, markers)