src/lib/istream-chain.c

	istream-chain.c revision 5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch/* Copyright (c) 2003-2012 Dovecot authors, see the included COPYING file */
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch#include "lib.h"
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch#include "llist.h"
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch#include "istream-private.h"
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch#include "istream-chain.h"
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschstruct chain_istream;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschstruct istream_chain_link {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream_chain_link *prev, *next;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream *stream;
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen    bool eof;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch};
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschstruct istream_chain {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream_chain_link *head, *tail;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct chain_istream *stream;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch};
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschstruct chain_istream {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream_private istream;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    size_t prev_stream_left, prev_skip;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream_chain chain;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch};
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainenstatic void ATTR_NULL(2)
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Siraineni_stream_chain_append_internal(struct istream_chain *chain,
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainen                   struct istream *stream)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch{
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream_chain_link *link;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    if (stream == NULL && chain->tail != NULL && chain->tail->stream == NULL)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        return;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    link = i_new(struct istream_chain_link, 1);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    link->stream = stream;
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen    link->eof = stream == NULL;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen    if (stream != NULL)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        i_stream_ref(stream);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    if (chain->head == NULL && stream != NULL) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        if (chain->stream->istream.max_buffer_size == 0) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            chain->stream->istream.max_buffer_size =
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch                stream->real_stream->max_buffer_size;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        } else {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            i_stream_set_max_buffer_size(stream,
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch                chain->stream->istream.max_buffer_size);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    DLLIST2_APPEND(&chain->head, &chain->tail, link);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch}
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainenvoid i_stream_chain_append(struct istream_chain *chain, struct istream *stream)
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainen{
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainen    return i_stream_chain_append_internal(chain, stream);
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainen}
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainen
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainenvoid i_stream_chain_append_eof(struct istream_chain *chain)
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainen{
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainen    return i_stream_chain_append_internal(chain, NULL);
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainen}
a10ed8c47534b4c6b6bf2711ccfe577e720a47b4Timo Sirainen
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschstatic void
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschi_stream_chain_set_max_buffer_size(struct iostream_private *stream,
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch                    size_t max_size)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch{
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct chain_istream *cstream = (struct chain_istream *)stream;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream_chain_link *link = cstream->chain.head;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.max_buffer_size = max_size;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    while (link != NULL) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        if (link->stream != NULL)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            i_stream_set_max_buffer_size(link->stream, max_size);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        link = link->next;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch}
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschstatic void i_stream_chain_destroy(struct iostream_private *stream)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch{
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct chain_istream *cstream = (struct chain_istream *)stream;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream_chain_link *link = cstream->chain.head;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    while (link != NULL) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        struct istream_chain_link *next = link->next;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        if (link->stream != NULL)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            i_stream_unref(&link->stream);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        i_free(link);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        link = next;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch}
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschstatic void i_stream_chain_read_next(struct chain_istream *cstream)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch{
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream_chain_link *link = cstream->chain.head;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream *prev_input;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    const unsigned char *data;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    size_t data_size, size;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    i_assert(link != NULL && link->stream != NULL);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    i_assert(link->stream->eof);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    prev_input = link->stream;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    data = i_stream_get_data(prev_input, &data_size);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    DLLIST2_REMOVE(&cstream->chain.head, &cstream->chain.tail, link);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    i_free(link);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen    /* a) we have more streams, b) we have EOF, c) we need to wait
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen       for more streams */
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    link = cstream->chain.head;
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen    if (link != NULL && link->stream != NULL)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        i_stream_seek(link->stream, 0);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    /* we already verified that the data size is less than the
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch       maximum buffer size */
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.pos = 0;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    if (data_size > 0) {
dd2df6a67f10792ce31a3666197c0b6885893a3aTimo Sirainen        if (!i_stream_try_alloc(&cstream->istream, data_size, &size))
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            i_unreached();
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        i_assert(size >= data_size);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->prev_stream_left = data_size;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    memcpy(cstream->istream.w_buffer, data, data_size);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    i_stream_skip(prev_input, data_size);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    i_stream_unref(&prev_input);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.skip = 0;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.pos = data_size;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch}
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschstatic ssize_t i_stream_chain_read(struct istream_private *stream)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch{
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct chain_istream *cstream = (struct chain_istream *)stream;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct istream_chain_link *link = cstream->chain.head;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    const unsigned char *data;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    size_t size, pos, cur_pos, bytes_skipped;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    ssize_t ret;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen    if (link != NULL && link->eof) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        stream->istream.eof = TRUE;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        return -1;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    i_assert(stream->skip >= cstream->prev_skip);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    bytes_skipped = stream->skip - cstream->prev_skip;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    if (cstream->prev_stream_left == 0) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        /* no need to worry about buffers, skip everything */
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        i_assert(cstream->prev_skip == 0);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    } else if (bytes_skipped < cstream->prev_stream_left) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        /* we're still skipping inside buffer */
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        cstream->prev_stream_left -= bytes_skipped;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        bytes_skipped = 0;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    } else {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        /* done with the buffer */
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        bytes_skipped -= cstream->prev_stream_left;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        cstream->prev_stream_left = 0;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    stream->pos -= bytes_skipped;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    stream->skip -= bytes_skipped;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    if (link == NULL) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        i_assert(bytes_skipped == 0);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        return 0;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    i_stream_skip(link->stream, bytes_skipped);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cur_pos = stream->pos - stream->skip - cstream->prev_stream_left;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    data = i_stream_get_data(link->stream, &pos);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    if (pos > cur_pos)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        ret = 0;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    else {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        /* need to read more */
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        i_assert(cur_pos == pos);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        ret = i_stream_read(link->stream);
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen        if (ret == -2 || ret == 0)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            return ret;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen        if (ret == -1) {
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen            if (link->stream->stream_errno != 0) {
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen                stream->istream.stream_errno =
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen                    link->stream->stream_errno;
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen                return -1;
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen            }
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen            /* EOF of this stream, go to next stream */
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            i_stream_chain_read_next(cstream);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            cstream->prev_skip = stream->skip;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            return i_stream_chain_read(stream);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        }
5afe997e79978b7e989aa3b0bfdf4a813ecdc6f6Timo Sirainen        /* we read something */
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        data = i_stream_get_data(link->stream, &pos);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    if (cstream->prev_stream_left == 0) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        stream->buffer = data;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        stream->pos -= stream->skip;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        stream->skip = 0;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    } else if (pos == cur_pos) {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        stream->buffer = stream->w_buffer;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    } else {
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        stream->buffer = stream->w_buffer;
dd2df6a67f10792ce31a3666197c0b6885893a3aTimo Sirainen        if (!i_stream_try_alloc(stream, pos - cur_pos, &size))
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            return -2;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        if (pos > size)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch            pos = size;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        memcpy(stream->w_buffer + stream->pos,
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch               data + cur_pos, pos - cur_pos);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    }
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    pos += stream->skip + cstream->prev_stream_left;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    ret = pos > stream->pos ? (ssize_t)(pos - stream->pos) :
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        (ret == 0 ? 0 : -1);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    stream->pos = pos;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->prev_skip = stream->skip;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    return ret;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch}
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Boschstruct istream *i_stream_create_chain(struct istream_chain **chain_r)
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch{
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    struct chain_istream *cstream;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream = i_new(struct chain_istream, 1);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->chain.stream = cstream;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.max_buffer_size = 256;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.iostream.destroy = i_stream_chain_destroy;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.iostream.set_max_buffer_size =
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch        i_stream_chain_set_max_buffer_size;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.read = i_stream_chain_read;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.istream.readable_fd = FALSE;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.istream.blocking = FALSE;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    cstream->istream.istream.seekable = FALSE;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    *chain_r = &cstream->chain;
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch    return i_stream_create(&cstream->istream, NULL, -1);
0fe2992e4d09f3ae4cceea88c9871c832d67b461Stephan Bosch}