src/lib/ostream-buffer.c

	ostream-buffer.c revision bcb4e51a409d94ae670de96afb8483a4f7855294
/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */

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

struct buffer_ostream {
    struct ostream_private ostream;
    buffer_t *buf;
    bool seeked;
};

static int o_stream_buffer_seek(struct ostream_private *stream, uoff_t offset)
{
    struct buffer_ostream *bstream = (struct buffer_ostream *)stream;

    bstream->seeked = TRUE;
    stream->ostream.offset = offset;
    return 1;
}

static int
o_stream_buffer_write_at(struct ostream_private *stream,
             const void *data, size_t size, uoff_t offset)
{
    struct buffer_ostream *bstream = (struct buffer_ostream *)stream;

    buffer_write(bstream->buf, offset, data, size);
    return 0;
}

static ssize_t
o_stream_buffer_sendv(struct ostream_private *stream,
              const struct const_iovec *iov, unsigned int iov_count)
{
    struct buffer_ostream *bstream = (struct buffer_ostream *)stream;
    size_t left, n, offset;
    ssize_t ret = 0;
    unsigned int i;

    offset = bstream->seeked ? stream->ostream.offset : bstream->buf->used;

    for (i = 0; i < iov_count; i++) {
        left = bstream->ostream.max_buffer_size -
            stream->ostream.offset;
        n = I_MIN(left, iov[i].iov_len);
        buffer_write(bstream->buf, offset, iov[i].iov_base, n);
        stream->ostream.offset += n; offset += n;
        ret += n;
        if (n != iov[i].iov_len)
            break;
    }
    return ret;
}

static size_t
o_stream_buffer_get_used_size(const struct ostream_private *stream)
{
    struct buffer_ostream *bstream = (struct buffer_ostream *)stream;

    return bstream->buf->used;
}

struct ostream *o_stream_create_buffer(buffer_t *buf)
{
    struct buffer_ostream *bstream;
    struct ostream *output;

    bstream = i_new(struct buffer_ostream, 1);
    /* we don't set buffer as blocking, because if max_buffer_size is
       changed it can get truncated. this is used in various places in
       unit tests. */
    bstream->ostream.max_buffer_size = (size_t)-1;
    bstream->ostream.seek = o_stream_buffer_seek;
    bstream->ostream.sendv = o_stream_buffer_sendv;
    bstream->ostream.write_at = o_stream_buffer_write_at;
    bstream->ostream.get_used_size = o_stream_buffer_get_used_size;

    bstream->buf = buf;
    output = o_stream_create(&bstream->ostream, NULL, -1);
    o_stream_set_name(output, "(buffer)");
    return output;
}