12.5.1 MultiFile Objects
A MultiFile instance has the following methods:
push(str)
- Push a boundary string. When an appropriately decorated version of
this boundary is found as an input line, it will be interpreted as a
section-divider or end-marker. All subsequent
reads will return the empty string to indicate end-of-file, until a
call to pop() removes the boundary a or next() call
reenables it.
It is possible to push more than one boundary. Encountering the
most-recently-pushed boundary will return EOF; encountering any other
boundary will raise an error.
readline(str)
- Read a line. If the line is data (not a section-divider or end-marker
or real EOF) return it. If the line matches the most-recently-stacked
boundary, return
'' and set self.last to 1 or 0 according as
the match is or is not an end-marker. If the line matches any other
stacked boundary, raise an error. On encountering end-of-file on the
underlying stream object, the method raises Error unless
all boundaries have been popped.
readlines(str)
- Return all lines remaining in this part as a list of strings.
read()
- Read all lines, up to the next section. Return them as a single
(multiline) string. Note that this doesn't take a size argument!
next()
- Skip lines to the next section (that is, read lines until a
section-divider or end-marker has been consumed). Return true if
there is such a section, false if an end-marker is seen. Re-enable
the most-recently-pushed boundary.
pop()
- Pop a section boundary. This boundary will no longer be interpreted
as EOF.
seek(pos[, whence])
- Seek. Seek indices are relative to the start of the current section.
The pos and whence arguments are interpreted as for a file
seek.
tell()
- Return the file position relative to the start of the current section.
is_data(str)
- Return true if str is data and false if it might be a section
boundary. As written, it tests for a prefix other than
'--' at
start of line (which all MIME boundaries have) but it is declared so
it can be overridden in derived classes.
Note that this test is used intended as a fast guard for the real
boundary tests; if it always returns false it will merely slow
processing, not cause it to fail.
section_divider(str)
- Turn a boundary into a section-divider line. By default, this
method prepends
'--' (which MIME section boundaries have) but
it is declared so it can be overridden in derived classes. This
method need not append LF or CR-LF, as comparison with the result
ignores trailing whitespace.
end_marker(str)
- Turn a boundary string into an end-marker line. By default, this
method prepends
'--' and appends '--' (like a
MIME-multipart end-of-message marker) but it is declared so it can be
be overridden in derived classes. This method need not append LF or
CR-LF, as comparison with the result ignores trailing whitespace.
Finally, MultiFile instances have two public instance variables:
level- Nesting depth of the current part.
last- True if the last end-of-file was for an end-of-message marker.
