istream-limit.c revision f30d2b798191d94f845463637610d6b833162d9b
/* Copyright (c) 2003-2008 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "istream-internal.h"
struct limit_istream {
struct istream_private istream;
uoff_t v_size;
};
static void i_stream_limit_destroy(struct iostream_private *stream)
{
struct limit_istream *lstream = (struct limit_istream *) stream;
uoff_t v_offset;
v_offset = lstream->istream.parent_start_offset +
lstream->istream.istream.v_offset;
if (lstream->istream.parent->seekable ||
v_offset > lstream->istream.parent->v_offset) {
/* get to same position in parent stream */
i_stream_seek(lstream->istream.parent, v_offset);
}
i_stream_unref(&lstream->istream.parent);
}
static void
i_stream_limit_set_max_buffer_size(struct iostream_private *stream,
size_t max_size)
{
struct limit_istream *lstream = (struct limit_istream *) stream;
lstream->istream.max_buffer_size = max_size;
i_stream_set_max_buffer_size(lstream->istream.parent, max_size);
}
static ssize_t i_stream_limit_read(struct istream_private *stream)
{
struct limit_istream *lstream = (struct limit_istream *) stream;
uoff_t left;
ssize_t ret;
size_t pos;
if (stream->istream.v_offset +
(stream->pos - stream->skip) >= lstream->v_size) {
stream->istream.eof = TRUE;
return -1;
}
if (stream->parent->v_offset !=
lstream->istream.parent_start_offset + stream->istream.v_offset) {
i_stream_seek(stream->parent,
lstream->istream.parent_start_offset +
stream->istream.v_offset);
}
stream->buffer = i_stream_get_data(stream->parent, &pos);
if (pos <= stream->pos) {
if ((ret = i_stream_read(stream->parent)) == -2)
return -2;
stream->istream.stream_errno = stream->parent->stream_errno;
stream->istream.eof = stream->parent->eof;
stream->buffer = i_stream_get_data(stream->parent, &pos);
} else {
ret = 0;
}
stream->pos -= stream->skip;
stream->skip = 0;
if (lstream->v_size != (uoff_t)-1) {
left = lstream->v_size - stream->istream.v_offset;
if (pos >= left) {
pos = left;
stream->istream.eof = TRUE;
}
}
ret = pos > stream->pos ? (ssize_t)(pos - stream->pos) :
(ret == 0 ? 0 : -1);
stream->pos = pos;
return ret;
}
static void i_stream_limit_seek(struct istream_private *stream, uoff_t v_offset,
bool mark ATTR_UNUSED)
{
struct limit_istream *lstream = (struct limit_istream *) stream;
i_assert(v_offset <= lstream->v_size);
stream->istream.stream_errno = 0;
stream->istream.v_offset = v_offset;
stream->skip = stream->pos = 0;
}
static const struct stat *
i_stream_limit_stat(struct istream_private *stream, bool exact)
{
struct limit_istream *lstream = (struct limit_istream *) stream;
const struct stat *st;
st = i_stream_stat(stream->parent, exact);
if (st == NULL)
return NULL;
stream->statbuf = *st;
if (lstream->v_size != (uoff_t)-1)
stream->statbuf.st_size = lstream->v_size;
return &stream->statbuf;
}
struct istream *i_stream_create_limit(struct istream *input, uoff_t v_size)
{
struct limit_istream *lstream;
i_stream_ref(input);
lstream = i_new(struct limit_istream, 1);
lstream->v_size = v_size;
lstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
lstream->istream.iostream.destroy = i_stream_limit_destroy;
lstream->istream.iostream.set_max_buffer_size =
i_stream_limit_set_max_buffer_size;
lstream->istream.parent = input;
lstream->istream.read = i_stream_limit_read;
lstream->istream.seek = i_stream_limit_seek;
lstream->istream.stat = i_stream_limit_stat;
lstream->istream.istream.blocking = input->blocking;
lstream->istream.istream.seekable = input->seekable;
return i_stream_create(&lstream->istream, input,
i_stream_get_fd(input));
}