src/lib-fs/ostream-metawrap.c

/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "istream.h"
#include "ostream-private.h"
#include "ostream-metawrap.h"

struct metawrap_ostream {
    struct ostream_private ostream;
    void (*write_callback)(void *);
    void *context;
};

static void o_stream_metawrap_call_callback(struct metawrap_ostream *mstream)
{
    void (*write_callback)(void *) = mstream->write_callback;

    if (write_callback != NULL) {
        mstream->write_callback = NULL;
        write_callback(mstream->context);
        /* metadata headers aren't counted as part of the offset */
        mstream->ostream.ostream.offset = 0;
    }
}

static ssize_t
o_stream_metawrap_sendv(struct ostream_private *stream,
            const struct const_iovec *iov, unsigned int iov_count)
{
    struct metawrap_ostream *mstream = (struct metawrap_ostream *)stream;
    ssize_t ret;

    o_stream_metawrap_call_callback(mstream);
    if ((ret = o_stream_sendv(stream->parent, iov, iov_count)) < 0)
        o_stream_copy_error_from_parent(stream);
    else
        stream->ostream.offset += ret;
    return ret;
}

static enum ostream_send_istream_result
o_stream_metawrap_send_istream(struct ostream_private *_outstream,
                   struct istream *instream)
{
    struct metawrap_ostream *outstream =
        (struct metawrap_ostream *)_outstream;
    uoff_t orig_instream_offset = instream->v_offset;
    enum ostream_send_istream_result res;

    o_stream_metawrap_call_callback(outstream);
    if ((res = o_stream_send_istream(_outstream->parent, instream)) == OSTREAM_SEND_ISTREAM_RESULT_ERROR_OUTPUT)
        o_stream_copy_error_from_parent(_outstream);
    _outstream->ostream.offset += instream->v_offset - orig_instream_offset;
    return res;
}

struct ostream *
o_stream_create_metawrap(struct ostream *output,
             void (*write_callback)(void *), void *context)
{
    struct metawrap_ostream *mstream;

    mstream = i_new(struct metawrap_ostream, 1);
    mstream->ostream.sendv = o_stream_metawrap_sendv;
    mstream->ostream.send_istream = o_stream_metawrap_send_istream;
    mstream->write_callback = write_callback;
    mstream->context = context;

    return o_stream_create(&mstream->ostream, output,
                   o_stream_get_fd(output));
}