istream-attachment.c [plain text]
#include "lib.h"
#include "istream-internal.h"
#include "istream-attachment.h"
struct attachment_istream {
struct istream_private istream;
uoff_t size;
};
static ssize_t i_stream_attachment_read(struct istream_private *stream)
{
struct attachment_istream *astream =
(struct attachment_istream *)stream;
uoff_t left;
ssize_t ret;
size_t pos;
if (stream->istream.v_offset +
(stream->pos - stream->skip) >= astream->size) {
stream->istream.eof = TRUE;
return -1;
}
i_stream_seek(stream->parent, astream->istream.parent_start_offset +
stream->istream.v_offset);
stream->pos -= stream->skip;
stream->skip = 0;
stream->buffer = i_stream_get_data(stream->parent, &pos);
if (pos > stream->pos)
ret = 0;
else do {
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);
} while (pos <= stream->pos && ret > 0);
left = astream->size - stream->istream.v_offset;
if (pos == left)
stream->istream.eof = TRUE;
else if (pos > left) {
i_error("Attachment file %s larger than expected "
"(%"PRIuUOFF_T")", i_stream_get_name(stream->parent),
astream->size);
pos = left;
stream->istream.eof = TRUE;
} else if (!stream->istream.eof) {
} else if (stream->istream.stream_errno == ENOENT) {
} else {
i_error("Attachment file %s smaller than expected "
"(%"PRIuUOFF_T" < %"PRIuUOFF_T")",
i_stream_get_name(stream->parent),
stream->istream.v_offset, astream->size);
stream->istream.stream_errno = EIO;
}
ret = pos > stream->pos ? (ssize_t)(pos - stream->pos) :
(ret == 0 ? 0 : -1);
stream->pos = pos;
i_assert(ret != -1 || stream->istream.eof ||
stream->istream.stream_errno != 0);
return ret;
}
static void
i_stream_attachment_seek(struct istream_private *stream,
uoff_t v_offset, bool mark ATTR_UNUSED)
{
struct attachment_istream *astream =
(struct attachment_istream *)stream;
i_assert(v_offset <= astream->size);
stream->istream.v_offset = v_offset;
stream->skip = stream->pos = 0;
}
static const struct stat *
i_stream_attachment_stat(struct istream_private *stream, bool exact ATTR_UNUSED)
{
struct attachment_istream *astream =
(struct attachment_istream *)stream;
const struct stat *st;
st = i_stream_stat(stream->parent, FALSE);
if (st == NULL)
return NULL;
stream->statbuf = *st;
stream->statbuf.st_size = astream->size;
return &stream->statbuf;
}
struct istream *i_stream_create_attachment(struct istream *input, uoff_t size)
{
struct attachment_istream *astream;
astream = i_new(struct attachment_istream, 1);
astream->size = size;
astream->istream.max_buffer_size = input->real_stream->max_buffer_size;
astream->istream.parent = input;
astream->istream.read = i_stream_attachment_read;
astream->istream.seek = i_stream_attachment_seek;
astream->istream.stat = i_stream_attachment_stat;
astream->istream.istream.readable_fd = input->readable_fd;
astream->istream.istream.blocking = input->blocking;
astream->istream.istream.seekable = input->seekable;
return i_stream_create(&astream->istream, input,
i_stream_get_fd(input));
}