istream-concat.c revision 64c48ffb71f1cf99acf375768fde4cff9b512648
/* Copyright (c) 2007-2010 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "buffer.h"
#include "istream-internal.h"
#include "istream-concat.h"
struct concat_istream {
struct istream_private istream;
struct istream **input, *cur_input;
uoff_t *input_size;
unsigned int cur_idx, unknown_size_idx;
size_t prev_stream_left, prev_skip;
};
static void i_stream_concat_close(struct iostream_private *stream)
{
struct concat_istream *cstream = (struct concat_istream *)stream;
unsigned int i;
for (i = 0; cstream->input[i] != NULL; i++)
i_stream_close(cstream->input[i]);
}
static void i_stream_concat_destroy(struct iostream_private *stream)
{
struct concat_istream *cstream = (struct concat_istream *)stream;
unsigned int i;
for (i = 0; cstream->input[i] != NULL; i++)
i_stream_unref(&cstream->input[i]);
i_free(cstream->input);
i_free(cstream->input_size);
i_free(cstream->istream.w_buffer);
}
static void
i_stream_concat_set_max_buffer_size(struct iostream_private *stream,
size_t max_size)
{
struct concat_istream *cstream = (struct concat_istream *)stream;
unsigned int i;
cstream->istream.max_buffer_size = max_size;
for (i = 0; cstream->input[i] != NULL; i++)
i_stream_set_max_buffer_size(cstream->input[i], max_size);
}
static void i_stream_concat_read_next(struct concat_istream *cstream)
{
const unsigned char *data;
size_t data_size, size;
i_assert(cstream->cur_input->eof);
data = i_stream_get_data(cstream->cur_input, &data_size);
cstream->cur_idx++;
cstream->cur_input = cstream->input[cstream->cur_idx];
i_stream_seek(cstream->cur_input, 0);
if (cstream->prev_stream_left > 0 || cstream->istream.pos == 0) {
cstream->prev_stream_left += data_size;
i_assert(cstream->prev_stream_left ==
cstream->istream.pos - cstream->istream.skip);
return;
}
/* we already verified that the data size is less than the
maximum buffer size */
cstream->istream.pos = 0;
if (data_size > 0) {
if (!i_stream_get_buffer_space(&cstream->istream,
data_size, &size))
i_unreached();
i_assert(size >= data_size);
}
cstream->prev_stream_left = data_size;
memcpy(cstream->istream.w_buffer, data, data_size);
cstream->istream.skip = 0;
cstream->istream.pos = data_size;
}
static ssize_t i_stream_concat_read(struct istream_private *stream)
{
struct concat_istream *cstream = (struct concat_istream *)stream;
const unsigned char *data;
size_t size, pos, cur_pos, bytes_skipped;
ssize_t ret;
bool last_stream;
if (cstream->cur_input == NULL) {
stream->istream.eof = TRUE;
return -1;
}
i_assert(stream->skip >= cstream->prev_skip);
bytes_skipped = stream->skip - cstream->prev_skip;
if (cstream->prev_stream_left == 0) {
/* no need to worry about buffers, skip everything */
i_assert(cstream->prev_skip == 0);
} else if (bytes_skipped < cstream->prev_stream_left) {
/* we're still skipping inside buffer */
cstream->prev_stream_left -= bytes_skipped;
bytes_skipped = 0;
} else {
/* done with the buffer */
bytes_skipped -= cstream->prev_stream_left;
cstream->prev_stream_left = 0;
}
i_stream_skip(cstream->cur_input, bytes_skipped);
stream->pos -= bytes_skipped;
stream->skip -= bytes_skipped;
cur_pos = stream->pos - stream->skip - cstream->prev_stream_left;
data = i_stream_get_data(cstream->cur_input, &pos);
if (pos > cur_pos)
ret = 0;
else {
/* need to read more */
i_assert(cur_pos == pos);
ret = i_stream_read(cstream->cur_input);
if (ret == -2 || ret == 0)
return ret;
if (ret == -1 && cstream->cur_input->stream_errno != 0) {
stream->istream.stream_errno =
cstream->cur_input->stream_errno;
return -1;
}
/* we either read something or we're at EOF */
last_stream = cstream->input[cstream->cur_idx+1] == NULL;
if (ret == -1 && !last_stream) {
if (stream->pos >= stream->max_buffer_size)
return -2;
i_stream_concat_read_next(cstream);
cstream->prev_skip = stream->skip;
return i_stream_concat_read(stream);
}
stream->istream.eof = cstream->cur_input->eof && last_stream;
i_assert(ret != -1 || stream->istream.eof);
data = i_stream_get_data(cstream->cur_input, &pos);
}
if (cstream->prev_stream_left == 0) {
stream->buffer = data;
stream->pos -= stream->skip;
stream->skip = 0;
} else if (pos == cur_pos) {
stream->buffer = stream->w_buffer;
} else {
stream->buffer = stream->w_buffer;
if (!i_stream_get_buffer_space(stream, pos - cur_pos, &size))
return -2;
if (pos > size)
pos = size;
memcpy(stream->w_buffer + stream->pos,
data + cur_pos, pos - cur_pos);
}
pos += stream->skip + cstream->prev_stream_left;
ret = pos > stream->pos ? (ssize_t)(pos - stream->pos) :
(ret == 0 ? 0 : -1);
stream->pos = pos;
cstream->prev_skip = stream->skip;
return ret;
}
static unsigned int
find_v_offset(struct concat_istream *cstream, uoff_t *v_offset)
{
const struct stat *st;
unsigned int i;
for (i = 0; cstream->input[i] != NULL; i++) {
if (*v_offset == 0) {
/* seek to beginning of this stream */
break;
}
if (i == cstream->unknown_size_idx) {
/* we'll need to figure out this stream's size */
st = i_stream_stat(cstream->input[i], TRUE);
if (st == NULL) {
cstream->istream.istream.stream_errno =
cstream->input[i]->stream_errno;
return (unsigned int)-1;
}
/* @UNSAFE */
cstream->input_size[i] = st->st_size;
cstream->unknown_size_idx = i + 1;
}
if (*v_offset < cstream->input_size[i])
break;
*v_offset -= cstream->input_size[i];
}
return i;
}
static void i_stream_concat_seek(struct istream_private *stream,
uoff_t v_offset, bool mark ATTR_UNUSED)
{
struct concat_istream *cstream = (struct concat_istream *)stream;
stream->istream.v_offset = v_offset;
stream->skip = stream->pos = 0;
cstream->prev_stream_left = 0;
cstream->prev_skip = 0;
cstream->cur_idx = find_v_offset(cstream, &v_offset);
if (cstream->cur_idx == (unsigned int)-1) {
cstream->cur_input = NULL;
return;
}
cstream->cur_input = cstream->input[cstream->cur_idx];
if (cstream->cur_input != NULL)
i_stream_seek(cstream->cur_input, v_offset);
}
static const struct stat *
i_stream_concat_stat(struct istream_private *stream, bool exact ATTR_UNUSED)
{
struct concat_istream *cstream = (struct concat_istream *)stream;
uoff_t v_offset = (uoff_t)-1;
unsigned int i;
/* make sure we have all sizes */
(void)find_v_offset(cstream, &v_offset);
stream->statbuf.st_size = 0;
for (i = 0; i < cstream->unknown_size_idx; i++)
stream->statbuf.st_size += cstream->input_size[i];
return &stream->statbuf;
}
struct istream *i_stream_create_concat(struct istream *input[])
{
struct concat_istream *cstream;
unsigned int count;
size_t max_buffer_size = I_STREAM_MIN_SIZE;
bool blocking = TRUE, seekable = TRUE;
/* if any of the streams isn't blocking or seekable, set ourself also
nonblocking/nonseekable */
for (count = 0; input[count] != NULL; count++) {
size_t cur_max = input[count]->real_stream->max_buffer_size;
if (cur_max > max_buffer_size)
max_buffer_size = cur_max;
if (!input[count]->blocking)
blocking = FALSE;
if (!input[count]->seekable)
seekable = FALSE;
i_stream_ref(input[count]);
}
i_assert(count != 0);
cstream = i_new(struct concat_istream, 1);
cstream->input = i_new(struct istream *, count + 1);
cstream->input_size = i_new(uoff_t, count + 1);
memcpy(cstream->input, input, sizeof(*input) * count);
cstream->cur_input = cstream->input[0];
i_stream_seek(cstream->cur_input, 0);
cstream->istream.iostream.close = i_stream_concat_close;
cstream->istream.iostream.destroy = i_stream_concat_destroy;
cstream->istream.iostream.set_max_buffer_size =
i_stream_concat_set_max_buffer_size;
cstream->istream.max_buffer_size = max_buffer_size;
cstream->istream.read = i_stream_concat_read;
cstream->istream.seek = i_stream_concat_seek;
cstream->istream.stat = i_stream_concat_stat;
cstream->istream.istream.readable_fd = FALSE;
cstream->istream.istream.blocking = blocking;
cstream->istream.istream.seekable = seekable;
return i_stream_create(&cstream->istream, NULL, -1);
}