src/lib/ostream-failure-at.c

	ostream-failure-at.c revision 9294b9ad2eb112258c247906b53010664f84e57b
/* Copyright (c) 2015 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "buffer.h"
#include "ostream-private.h"
#include "ostream-failure-at.h"

struct failure_at_ostream {
    struct ostream_private ostream;
    char *error_string;
    uoff_t failure_offset;
    bool failed;
};

static void o_stream_failure_at_destroy(struct iostream_private *stream)
{
    struct failure_at_ostream *fstream =
        (struct failure_at_ostream *)stream;

    i_free(fstream->error_string);
}

static ssize_t
o_stream_failure_at_sendv(struct ostream_private *stream,
              const struct const_iovec *iov, unsigned int iov_count)
{
    struct failure_at_ostream *fstream =
        (struct failure_at_ostream *)stream;
    unsigned int i;
    struct const_iovec *iov_dup;
    unsigned int iov_dup_count;
    uoff_t bytes_until_failure;
    ssize_t ret;

    if (fstream->failure_offset <= stream->ostream.offset) {
        io_stream_set_error(&stream->iostream, "%s",
                    fstream->error_string);
        stream->ostream.stream_errno = errno = EIO;
        fstream->failed = TRUE;
        return -1;
    }
    bytes_until_failure = fstream->failure_offset - stream->ostream.offset;

    iov_dup = i_new(struct const_iovec, iov_count);
    iov_dup_count = iov_count;
    for (i = 0; i < iov_count; i++) {
        iov_dup[i] = iov[i];
        if (iov_dup[i].iov_len >= bytes_until_failure) {
            iov_dup[i].iov_len = bytes_until_failure;
            iov_dup_count = i+1;
            break;
        }
    }
    ret = o_stream_sendv(stream->parent, iov_dup, iov_dup_count);
    i_free(iov_dup);

    if (ret < 0) {
        o_stream_copy_error_from_parent(stream);
        return -1;
    }
    stream->ostream.offset += ret;
    return ret;
}

static int
o_stream_failure_at_flush(struct ostream_private *stream)
{
    struct failure_at_ostream *fstream =
        (struct failure_at_ostream *)stream;

    if (fstream->failed) {
        io_stream_set_error(&stream->iostream, "%s",
                    fstream->error_string);
        stream->ostream.stream_errno = errno = EIO;
        return -1;
    }
    return o_stream_flush(stream->parent);
}

struct ostream *
o_stream_create_failure_at(struct ostream *output, uoff_t failure_offset,
               const char *error_string)
{
    struct failure_at_ostream *fstream;

    fstream = i_new(struct failure_at_ostream, 1);
    fstream->ostream.sendv = o_stream_failure_at_sendv;
    fstream->ostream.flush = o_stream_failure_at_flush;
    fstream->ostream.iostream.destroy = o_stream_failure_at_destroy;
    fstream->failure_offset = failure_offset;
    fstream->error_string = i_strdup(error_string);
    return o_stream_create(&fstream->ostream, output,
                   o_stream_get_fd(output));
}

struct ostream *
o_stream_create_failure_at_flush(struct ostream *output, const char *error_string)
{
    struct failure_at_ostream *fstream;

    fstream = i_new(struct failure_at_ostream, 1);
    fstream->ostream.flush = o_stream_failure_at_flush;
    fstream->ostream.iostream.destroy = o_stream_failure_at_destroy;
    fstream->error_string = i_strdup(error_string);
    fstream->failed = TRUE;
    return o_stream_create(&fstream->ostream, output,
                   o_stream_get_fd(output));
}