162 lines
4.7 KiB
Python
162 lines
4.7 KiB
Python
"""A readline()-style interface to the parts of a multipart message.
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The MultiFile class makes each part of a multipart message "feel" like
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an ordinary file, as long as you use fp.readline(). Allows recursive
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use, for nested multipart messages. Probably best used together
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with module mimetools.
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Suggested use:
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real_fp = open(...)
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fp = MultiFile(real_fp)
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"read some lines from fp"
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fp.push(separator)
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while 1:
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"read lines from fp until it returns an empty string" (A)
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if not fp.next(): break
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fp.pop()
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"read remaining lines from fp until it returns an empty string"
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The latter sequence may be used recursively at (A).
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It is also allowed to use multiple push()...pop() sequences.
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If seekable is given as 0, the class code will not do the bookkeeping
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it normally attempts in order to make seeks relative to the beginning of the
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current file part. This may be useful when using MultiFile with a non-
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seekable stream object.
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"""
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from warnings import warn
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warn("the multifile module has been deprecated since Python 2.5",
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DeprecationWarning, stacklevel=2)
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del warn
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__all__ = ["MultiFile","Error"]
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class Error(Exception):
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pass
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class MultiFile:
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seekable = 0
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def __init__(self, fp, seekable=1):
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self.fp = fp
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self.stack = []
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self.level = 0
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self.last = 0
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if seekable:
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self.seekable = 1
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self.start = self.fp.tell()
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self.posstack = []
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def tell(self):
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if self.level > 0:
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return self.lastpos
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return self.fp.tell() - self.start
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def seek(self, pos, whence=0):
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here = self.tell()
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if whence:
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if whence == 1:
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pos = pos + here
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elif whence == 2:
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if self.level > 0:
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pos = pos + self.lastpos
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else:
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raise Error, "can't use whence=2 yet"
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if not 0 <= pos <= here or \
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self.level > 0 and pos > self.lastpos:
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raise Error, 'bad MultiFile.seek() call'
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self.fp.seek(pos + self.start)
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self.level = 0
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self.last = 0
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def readline(self):
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if self.level > 0:
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return ''
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line = self.fp.readline()
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# Real EOF?
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if not line:
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self.level = len(self.stack)
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self.last = (self.level > 0)
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if self.last:
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raise Error, 'sudden EOF in MultiFile.readline()'
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return ''
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assert self.level == 0
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# Fast check to see if this is just data
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if self.is_data(line):
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return line
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else:
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# Ignore trailing whitespace on marker lines
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marker = line.rstrip()
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# No? OK, try to match a boundary.
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# Return the line (unstripped) if we don't.
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for i, sep in enumerate(reversed(self.stack)):
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if marker == self.section_divider(sep):
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self.last = 0
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break
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elif marker == self.end_marker(sep):
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self.last = 1
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break
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else:
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return line
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# We only get here if we see a section divider or EOM line
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if self.seekable:
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self.lastpos = self.tell() - len(line)
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self.level = i+1
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if self.level > 1:
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raise Error,'Missing endmarker in MultiFile.readline()'
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return ''
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def readlines(self):
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list = []
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while 1:
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line = self.readline()
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if not line: break
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list.append(line)
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return list
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def read(self): # Note: no size argument -- read until EOF only!
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return ''.join(self.readlines())
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def next(self):
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while self.readline(): pass
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if self.level > 1 or self.last:
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return 0
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self.level = 0
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self.last = 0
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if self.seekable:
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self.start = self.fp.tell()
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return 1
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def push(self, sep):
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if self.level > 0:
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raise Error, 'bad MultiFile.push() call'
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self.stack.append(sep)
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if self.seekable:
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self.posstack.append(self.start)
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self.start = self.fp.tell()
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def pop(self):
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if self.stack == []:
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raise Error, 'bad MultiFile.pop() call'
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if self.level <= 1:
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self.last = 0
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else:
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abslastpos = self.lastpos + self.start
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self.level = max(0, self.level - 1)
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self.stack.pop()
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if self.seekable:
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self.start = self.posstack.pop()
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if self.level > 0:
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self.lastpos = abslastpos - self.start
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def is_data(self, line):
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return line[:2] != '--'
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def section_divider(self, str):
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return "--" + str
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def end_marker(self, str):
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return "--" + str + "--"
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