istream-limit.c revision 1de2b5a16a455e018d8cbf72ee114d4b5d557a48
e59faf65ce864fe95dc00f5d52b8323cdbd0608aTimo Sirainen/* Copyright (c) 2003-2007 Dovecot authors, see the included COPYING file */
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen#include "lib.h"
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen#include "istream-internal.h"
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainenstruct limit_istream {
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen struct istream_private istream;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen uoff_t v_start_offset, v_size;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen};
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainenstatic void i_stream_limit_destroy(struct iostream_private *stream)
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen{
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen struct limit_istream *lstream = (struct limit_istream *) stream;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen /* get to same position in parent stream */
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen i_stream_seek(lstream->istream.parent, lstream->v_start_offset +
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.istream.v_offset);
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen i_stream_unref(&lstream->istream.parent);
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen}
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
4c1deab456fe8877bf025d11843167ac1f36327aTimo Sirainenstatic void
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Siraineni_stream_limit_set_max_buffer_size(struct iostream_private *stream,
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen size_t max_size)
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen{
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen struct limit_istream *lstream = (struct limit_istream *) stream;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.max_buffer_size = max_size;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen i_stream_set_max_buffer_size(lstream->istream.parent, max_size);
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen}
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainenstatic ssize_t i_stream_limit_read(struct istream_private *stream)
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen{
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen struct limit_istream *lstream = (struct limit_istream *) stream;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen uoff_t left;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen ssize_t ret;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen size_t pos;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen if (stream->istream.v_offset +
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen (stream->pos - stream->skip) >= lstream->v_size) {
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen stream->istream.eof = TRUE;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen return -1;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen }
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen if (stream->parent->v_offset !=
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->v_start_offset + stream->istream.v_offset) {
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen i_stream_seek(stream->parent,
a81b240cfe84231eac64084efd5b0e1e91a9e817Timo Sirainen lstream->v_start_offset +
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen stream->istream.v_offset);
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen }
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen stream->buffer = i_stream_get_data(stream->parent, &pos);
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen if (pos <= stream->pos) {
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen if ((ret = i_stream_read(stream->parent)) == -2)
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen return -2;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen stream->istream.stream_errno = stream->parent->stream_errno;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen stream->istream.eof = stream->parent->eof;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen stream->buffer = i_stream_get_data(stream->parent, &pos);
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen } else {
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen ret = 0;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen }
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen stream->pos -= stream->skip;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen stream->skip = 0;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen if (lstream->v_size != (uoff_t)-1) {
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen left = lstream->v_size - stream->istream.v_offset;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen if (pos >= left) {
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen pos = left;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen stream->istream.eof = TRUE;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen }
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen }
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen ret = pos > stream->pos ? (ssize_t)(pos - stream->pos) :
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen (ret == 0 ? 0 : -1);
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen stream->pos = pos;
d7b205394bd07152718152976dfa089e13253d7eTimo Sirainen return ret;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen}
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainenstatic void i_stream_limit_seek(struct istream_private *stream, uoff_t v_offset,
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen bool mark ATTR_UNUSED)
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen{
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen struct limit_istream *lstream = (struct limit_istream *) stream;
d7b205394bd07152718152976dfa089e13253d7eTimo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen i_assert(v_offset <= lstream->v_size);
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
d7b205394bd07152718152976dfa089e13253d7eTimo Sirainen stream->istream.stream_errno = 0;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen stream->istream.v_offset = v_offset;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen stream->skip = stream->pos = 0;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen}
d7b205394bd07152718152976dfa089e13253d7eTimo Sirainen
d7b205394bd07152718152976dfa089e13253d7eTimo Sirainenstatic const struct stat *
b58aafbd21b365117538f73f306d22f75acd91f1Timo Siraineni_stream_limit_stat(struct istream_private *stream, bool exact)
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen{
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen struct limit_istream *lstream = (struct limit_istream *) stream;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen const struct stat *st;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen st = i_stream_stat(stream->parent, exact);
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen if (st == NULL)
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen return NULL;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen stream->statbuf = *st;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen if (lstream->v_size != (uoff_t)-1)
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen stream->statbuf.st_size = lstream->v_size;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen return &stream->statbuf;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen}
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainenstruct istream *i_stream_create_limit(struct istream *input,
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen uoff_t v_start_offset, uoff_t v_size)
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen{
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen struct limit_istream *lstream;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen i_stream_ref(input);
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream = i_new(struct limit_istream, 1);
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->v_start_offset = v_start_offset;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->v_size = v_size;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.istream.v_offset =
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen input->v_offset < v_start_offset ? 0 :
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen input->v_offset - v_start_offset > v_size ? v_size :
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen input->v_offset - v_start_offset;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.iostream.destroy = i_stream_limit_destroy;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.iostream.set_max_buffer_size =
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen i_stream_limit_set_max_buffer_size;
b58aafbd21b365117538f73f306d22f75acd91f1Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.parent = input;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.read = i_stream_limit_read;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.seek = i_stream_limit_seek;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.stat = i_stream_limit_stat;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.istream.blocking = input->blocking;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen lstream->istream.istream.seekable = input->seekable;
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen return i_stream_create(&lstream->istream, i_stream_get_fd(input),
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen input->real_stream->abs_start_offset +
ea1f67e14d727496179ee4ff391f592bce8f4f2dTimo Sirainen v_start_offset);
ea1f67e14d727496179ee4ff391f592bce8f4f2dTimo Sirainen}
1ac7c8e9040e0d0b7e9f849e45b94bfe919595a9Timo Sirainen