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