From 30987004ceed01ffdeaa9fc32bea269eb9ff3050 Mon Sep 17 00:00:00 2001 From: Tomeu Vizoso Date: Tue, 22 May 2007 16:14:46 +0000 Subject: Implement the session store component in pyxpcom. --- (limited to 'json.py') diff --git a/json.py b/json.py new file mode 100644 index 0000000..a28a13e --- /dev/null +++ b/json.py @@ -0,0 +1,310 @@ +import string +import types + +## json.py implements a JSON (http://json.org) reader and writer. +## Copyright (C) 2005 Patrick D. Logan +## Contact mailto:patrickdlogan@stardecisions.com +## +## This library is free software; you can redistribute it and/or +## modify it under the terms of the GNU Lesser General Public +## License as published by the Free Software Foundation; either +## version 2.1 of the License, or (at your option) any later version. +## +## This library is distributed in the hope that it will be useful, +## but WITHOUT ANY WARRANTY; without even the implied warranty of +## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +## Lesser General Public License for more details. +## +## You should have received a copy of the GNU Lesser General Public +## License along with this library; if not, write to the Free Software +## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + + +class _StringGenerator(object): + def __init__(self, string): + self.string = string + self.index = -1 + def peek(self): + i = self.index + 1 + if i < len(self.string): + return self.string[i] + else: + return None + def next(self): + self.index += 1 + if self.index < len(self.string): + return self.string[self.index] + else: + raise StopIteration + def all(self): + return self.string + +class WriteException(Exception): + pass + +class ReadException(Exception): + pass + +class JsonReader(object): + hex_digits = {'A': 10,'B': 11,'C': 12,'D': 13,'E': 14,'F':15} + escapes = {'t':'\t','n':'\n','f':'\f','r':'\r','b':'\b'} + + def read(self, s): + self._generator = _StringGenerator(s) + result = self._read() + return result + + def _read(self): + self._eatWhitespace() + peek = self._peek() + if peek is None: + raise ReadException, "Nothing to read: '%s'" % self._generator.all() + if peek == '{': + return self._readObject() + elif peek == '[': + return self._readArray() + elif peek == '"': + return self._readString() + elif peek == '-' or peek.isdigit(): + return self._readNumber() + elif peek == 't': + return self._readTrue() + elif peek == 'f': + return self._readFalse() + elif peek == 'n': + return self._readNull() + elif peek == '/': + self._readComment() + return self._read() + else: + raise ReadException, "Input is not valid JSON: '%s'" % self._generator.all() + + def _readTrue(self): + self._assertNext('t', "true") + self._assertNext('r', "true") + self._assertNext('u', "true") + self._assertNext('e', "true") + return True + + def _readFalse(self): + self._assertNext('f', "false") + self._assertNext('a', "false") + self._assertNext('l', "false") + self._assertNext('s', "false") + self._assertNext('e', "false") + return False + + def _readNull(self): + self._assertNext('n', "null") + self._assertNext('u', "null") + self._assertNext('l', "null") + self._assertNext('l', "null") + return None + + def _assertNext(self, ch, target): + if self._next() != ch: + raise ReadException, "Trying to read %s: '%s'" % (target, self._generator.all()) + + def _readNumber(self): + isfloat = False + result = self._next() + peek = self._peek() + while peek is not None and (peek.isdigit() or peek == "."): + isfloat = isfloat or peek == "." + result = result + self._next() + peek = self._peek() + try: + if isfloat: + return float(result) + else: + return int(result) + except ValueError: + raise ReadException, "Not a valid JSON number: '%s'" % result + + def _readString(self): + result = "" + assert self._next() == '"' + try: + while self._peek() != '"': + ch = self._next() + if ch == "\\": + ch = self._next() + if ch in 'brnft': + ch = self.escapes[ch] + elif ch == "u": + ch4096 = self._next() + ch256 = self._next() + ch16 = self._next() + ch1 = self._next() + n = 4096 * self._hexDigitToInt(ch4096) + n += 256 * self._hexDigitToInt(ch256) + n += 16 * self._hexDigitToInt(ch16) + n += self._hexDigitToInt(ch1) + ch = unichr(n) + elif ch not in '"/\\': + raise ReadException, "Not a valid escaped JSON character: '%s' in %s" % (ch, self._generator.all()) + result = result + ch + except StopIteration: + raise ReadException, "Not a valid JSON string: '%s'" % self._generator.all() + assert self._next() == '"' + return result + + def _hexDigitToInt(self, ch): + try: + result = self.hex_digits[ch.upper()] + except KeyError: + try: + result = int(ch) + except ValueError: + raise ReadException, "The character %s is not a hex digit." % ch + return result + + def _readComment(self): + assert self._next() == "/" + second = self._next() + if second == "/": + self._readDoubleSolidusComment() + elif second == '*': + self._readCStyleComment() + else: + raise ReadException, "Not a valid JSON comment: %s" % self._generator.all() + + def _readCStyleComment(self): + try: + done = False + while not done: + ch = self._next() + done = (ch == "*" and self._peek() == "/") + if not done and ch == "/" and self._peek() == "*": + raise ReadException, "Not a valid JSON comment: %s, '/*' cannot be embedded in the comment." % self._generator.all() + self._next() + except StopIteration: + raise ReadException, "Not a valid JSON comment: %s, expected */" % self._generator.all() + + def _readDoubleSolidusComment(self): + try: + ch = self._next() + while ch != "\r" and ch != "\n": + ch = self._next() + except StopIteration: + pass + + def _readArray(self): + result = [] + assert self._next() == '[' + done = self._peek() == ']' + while not done: + item = self._read() + result.append(item) + self._eatWhitespace() + done = self._peek() == ']' + if not done: + ch = self._next() + if ch != ",": + raise ReadException, "Not a valid JSON array: '%s' due to: '%s'" % (self._generator.all(), ch) + assert ']' == self._next() + return result + + def _readObject(self): + result = {} + assert self._next() == '{' + done = self._peek() == '}' + while not done: + key = self._read() + if type(key) is not types.StringType: + raise ReadException, "Not a valid JSON object key (should be a string): %s" % key + self._eatWhitespace() + ch = self._next() + if ch != ":": + raise ReadException, "Not a valid JSON object: '%s' due to: '%s'" % (self._generator.all(), ch) + self._eatWhitespace() + val = self._read() + result[key] = val + self._eatWhitespace() + done = self._peek() == '}' + if not done: + ch = self._next() + if ch != ",": + raise ReadException, "Not a valid JSON array: '%s' due to: '%s'" % (self._generator.all(), ch) + assert self._next() == "}" + return result + + def _eatWhitespace(self): + p = self._peek() + while p is not None and p in string.whitespace or p == '/': + if p == '/': + self._readComment() + else: + self._next() + p = self._peek() + + def _peek(self): + return self._generator.peek() + + def _next(self): + return self._generator.next() + +class JsonWriter(object): + + def _append(self, s): + self._results.append(s) + + def write(self, obj, escaped_forward_slash=False): + self._escaped_forward_slash = escaped_forward_slash + self._results = [] + self._write(obj) + return "".join(self._results) + + def _write(self, obj): + ty = type(obj) + if ty is types.DictType: + n = len(obj) + self._append("{") + for k, v in obj.items(): + self._write(k) + self._append(":") + self._write(v) + n = n - 1 + if n > 0: + self._append(",") + self._append("}") + elif ty is types.ListType or ty is types.TupleType: + n = len(obj) + self._append("[") + for item in obj: + self._write(item) + n = n - 1 + if n > 0: + self._append(",") + self._append("]") + elif ty is types.StringType or ty is types.UnicodeType: + self._append('"') + obj = obj.replace('\\', r'\\') + if self._escaped_forward_slash: + obj = obj.replace('/', r'\/') + obj = obj.replace('"', r'\"') + obj = obj.replace('\b', r'\b') + obj = obj.replace('\f', r'\f') + obj = obj.replace('\n', r'\n') + obj = obj.replace('\r', r'\r') + obj = obj.replace('\t', r'\t') + self._append(obj) + self._append('"') + elif ty is types.IntType or ty is types.LongType: + self._append(str(obj)) + elif ty is types.FloatType: + self._append("%f" % obj) + elif obj is True: + self._append("true") + elif obj is False: + self._append("false") + elif obj is None: + self._append("null") + else: + raise WriteException, "Cannot write in JSON: %s" % repr(obj) + +def write(obj, escaped_forward_slash=False): + return JsonWriter().write(obj, escaped_forward_slash) + +def read(s): + return JsonReader().read(s) -- cgit v0.9.1