istream-dot.c revision da2aa032ccfa8e7e4a4380ef738014549f4d2c2d
/* Copyright (c) 2007-2009 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "istream-internal.h"
#include "istream-dot.h"
struct dot_istream {
struct istream_private istream;
uoff_t prev_parent_offset;
char pending[3]; /* max. \r\n */
/* how far in string "\r\n.\r" are we */
unsigned int state;
/* state didn't actually start with \r */
unsigned int state_no_cr:1;
/* state didn't contain \n either (only at the beginnign of stream) */
unsigned int state_no_lf:1;
/* we've seen the "." line, keep returning EOF */
unsigned int dot_eof:1;
unsigned int send_last_lf:1;
};
static int i_stream_dot_read_some(struct dot_istream *dstream)
{
struct istream_private *stream = &dstream->istream;
size_t size;
ssize_t ret;
(void)i_stream_get_data(stream->parent, &size);
if (size == 0) {
ret = i_stream_read(stream->parent);
if (ret <= 0 && (ret != -2 || stream->skip == 0)) {
if (stream->parent->stream_errno != 0) {
stream->istream.stream_errno =
stream->parent->stream_errno;
} else if (ret < 0 && stream->parent->eof) {
/* we didn't see "." line */
stream->istream.stream_errno = EPIPE;
}
return ret;
}
(void)i_stream_get_data(stream->parent, &size);
i_assert(size != 0);
}
if (!i_stream_get_buffer_space(stream, size, NULL))
return -2;
return 1;
}
static bool flush_pending(struct dot_istream *dstream, size_t *destp)
{
struct istream_private *stream = &dstream->istream;
size_t dest = *destp;
unsigned int i = 0;
for (; dstream->pending[i] != '\0' && dest < stream->buffer_size; i++)
stream->w_buffer[dest++] = dstream->pending[i];
memmove(dstream->pending, dstream->pending + i,
sizeof(dstream->pending) - i);
*destp = dest;
return dest < stream->buffer_size;
}
static bool flush_dot_state(struct dot_istream *dstream, size_t *destp)
{
unsigned int i = 0;
if (!dstream->state_no_cr)
dstream->pending[i++] = '\r';
if (dstream->state_no_lf)
dstream->state_no_lf = FALSE;
else if (dstream->state > 1)
dstream->pending[i++] = '\n';
dstream->pending[i] = '\0';
if (dstream->state != 4)
dstream->state = 0;
else {
/* \r\n.\r seen, go back to \r state */
dstream->state = 1;
}
return flush_pending(dstream, destp);
}
static void i_stream_dot_eof(struct dot_istream *dstream, size_t *destp)
{
if (dstream->send_last_lf) {
dstream->state = 2;
(void)flush_dot_state(dstream, destp);
}
dstream->dot_eof = TRUE;
}
static ssize_t
i_stream_dot_return(struct istream_private *stream, size_t dest, ssize_t ret)
{
if (dest != stream->pos) {
i_assert(dest > stream->pos);
ret = dest - stream->pos;
stream->pos = dest;
}
return ret;
}
static ssize_t i_stream_dot_read(struct istream_private *stream)
{
/* @UNSAFE */
struct dot_istream *dstream = (struct dot_istream *)stream;
const unsigned char *data;
size_t i, dest, size;
ssize_t ret, ret1;
if (dstream->pending[0] != '\0') {
if (!i_stream_get_buffer_space(stream, 1, NULL))
return -2;
dest = stream->pos;
(void)flush_pending(dstream, &dest);
} else {
dest = stream->pos;
}
if (dstream->dot_eof) {
stream->istream.eof = TRUE;
return i_stream_dot_return(stream, dest, -1);
}
/* we have to update stream->pos before reading more data */
ret1 = i_stream_dot_return(stream, dest, 0);
i_assert(dstream->prev_parent_offset == stream->parent->v_offset);
if ((ret = i_stream_dot_read_some(dstream)) <= 0) {
if (ret1 != 0)
return ret1;
dest = stream->pos;
if (ret == -1 && dstream->state != 0)
(void)flush_dot_state(dstream, &dest);
return i_stream_dot_return(stream, dest, ret);
}
dest = stream->pos;
data = i_stream_get_data(stream->parent, &size);
for (i = 0; i < size && dest < stream->buffer_size; i++) {
switch (dstream->state) {
case 0:
break;
case 1:
/* CR seen */
if (data[i] == '\n')
dstream->state++;
else {
if (!flush_dot_state(dstream, &dest))
goto end;
}
break;
case 2:
/* [CR]LF seen */
if (data[i] == '.')
dstream->state++;
else {
if (!flush_dot_state(dstream, &dest))
goto end;
}
break;
case 3:
/* [CR]LF. seen */
if (data[i] == '\r')
dstream->state++;
else if (data[i] == '\n') {
/* EOF */
i_stream_dot_eof(dstream, &dest);
i++;
goto end;
} else {
/* drop the initial dot */
if (!flush_dot_state(dstream, &dest))
goto end;
}
break;
case 4:
/* [CR]LF.CR seen */
if (data[i] == '\n') {
/* EOF */
i_stream_dot_eof(dstream, &dest);
i++;
goto end;
} else {
/* drop the initial dot */
if (!flush_dot_state(dstream, &dest))
goto end;
}
}
if (dstream->state == 0) {
if (data[i] == '\r') {
dstream->state = 1;
dstream->state_no_cr = FALSE;
} else if (data[i] == '\n') {
dstream->state = 2;
dstream->state_no_cr = TRUE;
} else {
stream->w_buffer[dest++] = data[i];
}
}
}
end:
i_stream_skip(stream->parent, i);
dstream->prev_parent_offset = stream->parent->v_offset;
ret = i_stream_dot_return(stream, dest, 0) + ret1;
if (ret == 0)
return i_stream_dot_read(stream);
i_assert(ret > 0);
return ret;
}
static const struct stat *
i_stream_dot_stat(struct istream_private *stream, bool exact)
{
return i_stream_stat(stream->parent, exact);
}
struct istream *i_stream_create_dot(struct istream *input, bool send_last_lf)
{
struct dot_istream *dstream;
dstream = i_new(struct dot_istream, 1);
dstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
dstream->istream.read = i_stream_dot_read;
dstream->istream.stat = i_stream_dot_stat;
dstream->istream.istream.readable_fd = FALSE;
dstream->istream.istream.blocking = input->blocking;
dstream->istream.istream.seekable = FALSE;
dstream->send_last_lf = send_last_lf;
dstream->state = 2;
dstream->state_no_cr = TRUE;
dstream->state_no_lf = TRUE;
dstream->prev_parent_offset = input->v_offset;
return i_stream_create(&dstream->istream, input,
i_stream_get_fd(input));
}