mirror of
https://github.com/python/cpython.git
synced 2024-11-30 13:24:13 +08:00
129 lines
3.1 KiB
Python
129 lines
3.1 KiB
Python
# 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.
|
|
# Note that if a nested multipart message is terminated by a separator
|
|
# for an outer message, this is not reported, even though it is really
|
|
# illegal input.
|
|
|
|
import sys
|
|
import string
|
|
|
|
err = sys.stderr.write
|
|
|
|
Error = 'multifile.Error'
|
|
|
|
class MultiFile:
|
|
#
|
|
def __init__(self, fp):
|
|
self.fp = fp
|
|
self.stack = [] # Grows down
|
|
self.level = 0
|
|
self.last = 0
|
|
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):
|
|
if not 0 <= pos <= self.tell() 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()
|
|
if not line:
|
|
self.level = len(self.stack)
|
|
self.last = (self.level > 0)
|
|
if self.last:
|
|
err('*** Sudden EOF in MultiFile.readline()\n')
|
|
return ''
|
|
if line[:2] <> '--': return line
|
|
n = len(line)
|
|
k = n
|
|
while k > 0 and line[k-1] in string.whitespace: k = k-1
|
|
mark = line[2:k]
|
|
if mark[-2:] == '--': mark1 = mark[:-2]
|
|
else: mark1 = None
|
|
for i in range(len(self.stack)):
|
|
sep = self.stack[i]
|
|
if sep == mark:
|
|
self.last = 0
|
|
break
|
|
elif mark1 <> None and sep == mark1:
|
|
self.last = 1
|
|
break
|
|
else:
|
|
return line
|
|
# Get here after break out of loop
|
|
self.lastpos = self.tell() - len(line)
|
|
self.level = i+1
|
|
if self.level > 1:
|
|
err('*** Missing endmarker in MultiFile.readline()\n')
|
|
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
|
|
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)
|
|
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]
|
|
self.start = self.posstack[0]
|
|
del self.posstack[0]
|
|
if self.level > 0:
|
|
self.lastpos = abslastpos - self.start
|
|
#
|