src/lib/istream.c

	istream.c revision 4c096615cb86a826fda377b87df22c579bfe5525
2ronwalf/* Copyright (c) 2002-2014 Dovecot authors, see the included COPYING file */
2ronwalf
2ronwalf#include "lib.h"
2ronwalf#include "ioloop.h"
2ronwalf#include "array.h"
2ronwalf#include "str.h"
2ronwalf#include "istream-private.h"
2ronwalf
2ronwalfvoid i_stream_set_name(struct istream *stream, const char *name)
2ronwalf{
2ronwalf    i_free(stream->real_stream->iostream.name);
2ronwalf    stream->real_stream->iostream.name = i_strdup(name);
2ronwalf}
2ronwalf
2ronwalfconst char *i_stream_get_name(struct istream *stream)
2ronwalf{
2ronwalf    while (stream->real_stream->iostream.name == NULL) {
2ronwalf        stream = stream->real_stream->parent;
2ronwalf        if (stream == NULL)
2ronwalf            return "";
2ronwalf    }
2ronwalf    return stream->real_stream->iostream.name;
2ronwalf}
2ronwalf
2ronwalfstatic void i_stream_close_full(struct istream *stream, bool close_parents)
2ronwalf{
2ronwalf    io_stream_close(&stream->real_stream->iostream, close_parents);
2ronwalf    stream->closed = TRUE;
2ronwalf
2ronwalf    if (stream->stream_errno == 0)
2ronwalf        stream->stream_errno = EPIPE;
2ronwalf}
2ronwalf
2ronwalfvoid i_stream_destroy(struct istream **stream)
2ronwalf{
2ronwalf    i_stream_close_full(*stream, FALSE);
2ronwalf    i_stream_unref(stream);
2ronwalf}
2ronwalf
2ronwalfvoid i_stream_ref(struct istream *stream)
2ronwalf{
2ronwalf    io_stream_ref(&stream->real_stream->iostream);
2ronwalf}
2ronwalf
2ronwalfvoid i_stream_unref(struct istream **stream)
2ronwalf{
2ronwalf    struct istream_private *_stream = (*stream)->real_stream;
16daenzerorama
2ronwalf    if (_stream->iostream.refcount == 1) {
2ronwalf        if (_stream->line_str != NULL)
2ronwalf            str_free(&_stream->line_str);
2ronwalf    }
2ronwalf    io_stream_unref(&(*stream)->real_stream->iostream);
2ronwalf    *stream = NULL;
2ronwalf}
2ronwalf
2ronwalf#undef i_stream_add_destroy_callback
2ronwalfvoid i_stream_add_destroy_callback(struct istream *stream,
2ronwalf                   istream_callback_t *callback, void *context)
2ronwalf{
2ronwalf    struct iostream_private *iostream = &stream->real_stream->iostream;
2ronwalf    struct iostream_destroy_callback *dc;
2ronwalf
2ronwalf    if (!array_is_created(&iostream->destroy_callbacks))
2ronwalf        i_array_init(&iostream->destroy_callbacks, 2);
2ronwalf    dc = array_append_space(&iostream->destroy_callbacks);
2ronwalf    dc->callback = callback;
2ronwalf    dc->context = context;
2ronwalf}
2ronwalf
2ronwalfvoid i_stream_remove_destroy_callback(struct istream *stream,
16daenzerorama                      void (*callback)())
2ronwalf{
2ronwalf    struct iostream_private *iostream = &stream->real_stream->iostream;
2ronwalf    const struct iostream_destroy_callback *dcs;
2ronwalf    unsigned int i, count;
2ronwalf
2ronwalf    dcs = array_get(&iostream->destroy_callbacks, &count);
16daenzerorama    for (i = 0; i < count; i++) {
2ronwalf        if (dcs[i].callback == callback) {
2ronwalf            array_delete(&iostream->destroy_callbacks, i, 1);
2ronwalf            return;
2ronwalf        }
2ronwalf    }
2ronwalf    i_unreached();
2ronwalf}
2ronwalf
2ronwalfint i_stream_get_fd(struct istream *stream)
2ronwalf{
2ronwalf    struct istream_private *_stream = stream->real_stream;
2ronwalf
2ronwalf    return _stream->fd;
2ronwalf}
2ronwalf
16daenzeroramaconst char *i_stream_get_error(struct istream *stream)
16daenzerorama{
16daenzerorama    struct istream *s;
16daenzerorama
2ronwalf    /* we'll only return errors for streams that have stream_errno set.
2ronwalf       we might be returning unintended error otherwise. */
2ronwalf    if (stream->stream_errno == 0)
2ronwalf        return "<no error>";
2ronwalf
2ronwalf    for (s = stream; s != NULL; s = s->real_stream->parent) {
2ronwalf        if (s->stream_errno == 0)
2ronwalf            break;
2ronwalf        if (s->real_stream->iostream.error != NULL)
2ronwalf            return s->real_stream->iostream.error;
2ronwalf    }
2ronwalf    return strerror(stream->stream_errno);
2ronwalf}
2ronwalf
16daenzeroramavoid i_stream_close(struct istream *stream)
2ronwalf{
2ronwalf    i_stream_close_full(stream, TRUE);
16daenzerorama}
16daenzerorama
16daenzeroramavoid i_stream_set_init_buffer_size(struct istream *stream, size_t size)
16daenzerorama{
2ronwalf    stream->real_stream->init_buffer_size = size;
16daenzerorama}
2ronwalf
2ronwalfvoid i_stream_set_max_buffer_size(struct istream *stream, size_t max_size)
2ronwalf{
2ronwalf    io_stream_set_max_buffer_size(&stream->real_stream->iostream, max_size);
2ronwalf}
2ronwalf
2ronwalfsize_t i_stream_get_max_buffer_size(struct istream *stream)
2ronwalf{
2ronwalf    return stream->real_stream->max_buffer_size;
2ronwalf}
2ronwalf
2ronwalfvoid i_stream_set_return_partial_line(struct istream *stream, bool set)
2ronwalf{
2ronwalf    stream->real_stream->return_nolf_line = set;
2ronwalf}
2ronwalf
2ronwalfstatic void i_stream_update(struct istream_private *stream)
2ronwalf{
2ronwalf    if (stream->parent == NULL)
2ronwalf        stream->access_counter++;
2ronwalf    else {
2ronwalf        stream->access_counter =
2ronwalf            stream->parent->real_stream->access_counter;
2ronwalf        stream->parent_expected_offset = stream->parent->v_offset;
2ronwalf    }
2ronwalf}
2ronwalf
2ronwalfssize_t i_stream_read(struct istream *stream)
2ronwalf{
2ronwalf    struct istream_private *_stream = stream->real_stream;
15daenzerorama    size_t old_size;
2ronwalf    ssize_t ret;
2ronwalf
2ronwalf    if (unlikely(stream->closed || stream->stream_errno != 0)) {
2ronwalf        errno = stream->stream_errno;
2ronwalf        return -1;
15daenzerorama    }
2ronwalf
2ronwalf    stream->eof = FALSE;
2ronwalf
2ronwalf    if (_stream->parent != NULL)
2ronwalf        i_stream_seek(_stream->parent, _stream->parent_expected_offset);
2ronwalf
2ronwalf    old_size = _stream->pos - _stream->skip;
2ronwalf    ret = _stream->read(_stream);
2ronwalf    i_assert(old_size <= _stream->pos - _stream->skip);
2ronwalf    switch (ret) {
2ronwalf    case -2:
2ronwalf        i_assert(_stream->skip != _stream->pos);
2ronwalf        break;
2ronwalf    case -1:
2ronwalf        if (stream->stream_errno != 0) {
2ronwalf            /* error handling should be easier if we now just
2ronwalf               assume the stream is now at EOF */
15daenzerorama            stream->eof = TRUE;
2ronwalf            errno = stream->stream_errno;
2ronwalf        } else {
2ronwalf            i_assert(stream->eof);
2ronwalf            i_assert(old_size == _stream->pos - _stream->skip);
2ronwalf        }
2ronwalf        break;
2ronwalf    case 0:
2ronwalf        i_assert(!stream->blocking);
15daenzerorama        break;
16daenzerorama    default:
15daenzerorama        i_assert(ret > 0);
16daenzerorama        i_assert(_stream->skip < _stream->pos);
16daenzerorama        i_assert((size_t)ret+old_size == _stream->pos - _stream->skip);
16daenzerorama        break;
15daenzerorama    }
16daenzerorama
16daenzerorama    i_stream_update(_stream);
16daenzerorama    return ret;
16daenzerorama}
16daenzerorama
16daenzeroramassize_t i_stream_read_copy_from_parent(struct istream *istream)
15daenzerorama{
15daenzerorama    struct istream_private *stream = istream->real_stream;
15daenzerorama    size_t pos;
15daenzerorama    ssize_t ret;
15daenzerorama
15daenzerorama    stream->pos -= stream->skip;
15daenzerorama    stream->skip = 0;
15daenzerorama
15daenzerorama    stream->buffer = i_stream_get_data(stream->parent, &pos);
15daenzerorama    if (pos > stream->pos)
16daenzerorama        ret = 0;
16daenzerorama    else do {
16daenzerorama        if ((ret = i_stream_read(stream->parent)) == -2)
15daenzerorama            return -2;
15daenzerorama
15daenzerorama        stream->istream.stream_errno = stream->parent->stream_errno;
15daenzerorama        stream->istream.eof = stream->parent->eof;
15daenzerorama        stream->buffer = i_stream_get_data(stream->parent, &pos);
16daenzerorama        /* check again, in case the parent stream had been seeked
16daenzerorama           backwards and the previous read() didn't get us far
16daenzerorama           enough. */
16daenzerorama    } while (pos <= stream->pos && ret > 0);
16daenzerorama
16daenzerorama    ret = pos > stream->pos ? (ssize_t)(pos - stream->pos) :
15daenzerorama        (ret == 0 ? 0 : -1);
15daenzerorama    stream->pos = pos;
15daenzerorama    i_assert(ret != -1 || stream->istream.eof ||
15daenzerorama         stream->istream.stream_errno != 0);
2ronwalf    return ret;
2ronwalf}
2ronwalf
2ronwalfvoid i_stream_skip(struct istream *stream, uoff_t count)
2ronwalf{
2ronwalf    struct istream_private *_stream = stream->real_stream;
2ronwalf    size_t data_size;
2ronwalf
2ronwalf    data_size = _stream->pos - _stream->skip;
2ronwalf    if (count <= data_size) {
2ronwalf        /* within buffer */
2ronwalf        stream->v_offset += count;
2ronwalf        _stream->skip += count;
2ronwalf        return;
2ronwalf    }
2ronwalf
2ronwalf    /* have to seek forward */
2ronwalf    count -= data_size;
2ronwalf    _stream->skip = _stream->pos;
2ronwalf    stream->v_offset += data_size;
2ronwalf
2ronwalf    if (unlikely(stream->closed))
16daenzerorama        return;
2ronwalf
2ronwalf    stream->stream_errno = 0;
2ronwalf    _stream->seek(_stream, stream->v_offset + count, FALSE);
2ronwalf}
16daenzerorama
2ronwalfstatic bool i_stream_can_optimize_seek(struct istream_private *stream)
2ronwalf{
2ronwalf    if (stream->parent == NULL)
2ronwalf        return TRUE;
2ronwalf
2ronwalf    /* use the fast route only if the parent stream hasn't been changed */
2ronwalf    if (stream->access_counter !=
2ronwalf        stream->parent->real_stream->access_counter)
2ronwalf        return FALSE;
2ronwalf
    return i_stream_can_optimize_seek(stream->parent->real_stream);
}

void i_stream_seek(struct istream *stream, uoff_t v_offset)
{
    struct istream_private *_stream = stream->real_stream;

    if (v_offset >= stream->v_offset &&
        i_stream_can_optimize_seek(_stream))
        i_stream_skip(stream, v_offset - stream->v_offset);
    else {
        if (unlikely(stream->closed))
            return;

        stream->eof = FALSE;
        _stream->seek(_stream, v_offset, FALSE);
    }
    i_stream_update(_stream);
}

void i_stream_seek_mark(struct istream *stream, uoff_t v_offset)
{
    struct istream_private *_stream = stream->real_stream;

    if (unlikely(stream->closed))
        return;

    stream->eof = FALSE;
    _stream->seek(_stream, v_offset, TRUE);
    i_stream_update(_stream);
}

void i_stream_sync(struct istream *stream)
{
    struct istream_private *_stream = stream->real_stream;

    if (unlikely(stream->closed))
        return;

    if (_stream->sync != NULL) {
        _stream->sync(_stream);
        i_stream_update(_stream);
    }
}

int i_stream_stat(struct istream *stream, bool exact, const struct stat **st_r)
{
    struct istream_private *_stream = stream->real_stream;

    if (unlikely(stream->closed))
        return -1;

    if (_stream->stat(_stream, exact) < 0)
        return -1;
    *st_r = &_stream->statbuf;
    return 0;
}

int i_stream_get_size(struct istream *stream, bool exact, uoff_t *size_r)
{
    struct istream_private *_stream = stream->real_stream;

    if (unlikely(stream->closed))
        return -1;

    return _stream->get_size(_stream, exact, size_r);
}

bool i_stream_have_bytes_left(const struct istream *stream)
{
    const struct istream_private *_stream = stream->real_stream;

    return !stream->eof || _stream->skip != _stream->pos;
}

bool i_stream_is_eof(struct istream *stream)
{
    const struct istream_private *_stream = stream->real_stream;

    if (_stream->skip == _stream->pos)
        (void)i_stream_read(stream);
    return !i_stream_have_bytes_left(stream);
}

uoff_t i_stream_get_absolute_offset(struct istream *stream)
{
    return stream->real_stream->abs_start_offset + stream->v_offset;
}

static char *i_stream_next_line_finish(struct istream_private *stream, size_t i)
{
    char *ret;
    size_t end;

    if (i > 0 && stream->buffer[i-1] == '\r') {
        end = i - 1;
        stream->line_crlf = TRUE;
    } else {
        end = i;
        stream->line_crlf = FALSE;
    }

    if (stream->w_buffer != NULL) {
        /* modify the buffer directly */
        stream->w_buffer[end] = '\0';
        ret = (char *)stream->w_buffer + stream->skip;
    } else {
        /* use a temporary string to return it */
        if (stream->line_str == NULL)
            stream->line_str = str_new(default_pool, 256);
        str_truncate(stream->line_str, 0);
        str_append_n(stream->line_str, stream->buffer + stream->skip,
                 end - stream->skip);
        ret = str_c_modifiable(stream->line_str);
    }

    if (i < stream->pos)
        i++;
    stream->istream.v_offset += i - stream->skip;
    stream->skip = i;
    return ret;
}

static char *i_stream_last_line(struct istream_private *_stream)
{
    if (_stream->istream.eof && _stream->skip != _stream->pos &&
        _stream->return_nolf_line) {
        /* the last line is missing LF and we want to return it. */
        return i_stream_next_line_finish(_stream, _stream->pos);
    }
    return NULL;
}

char *i_stream_next_line(struct istream *stream)
{
    struct istream_private *_stream = stream->real_stream;
    const unsigned char *pos;

    if (_stream->skip >= _stream->pos) {
        if (!unlikely(stream->closed))
            stream->stream_errno = 0;
        return NULL;
    }

    pos = memchr(_stream->buffer + _stream->skip, '\n',
             _stream->pos - _stream->skip);
    if (pos != NULL) {
        return i_stream_next_line_finish(_stream,
                         pos - _stream->buffer);
    } else {
        return i_stream_last_line(_stream);
    }
}

char *i_stream_read_next_line(struct istream *stream)
{
    char *line;

    for (;;) {
        line = i_stream_next_line(stream);
        if (line != NULL)
            break;

        switch (i_stream_read(stream)) {
        case -2:
            stream->stream_errno = ENOBUFS;
            stream->eof = TRUE;
            return NULL;
        case -1:
            return i_stream_last_line(stream->real_stream);
        case 0:
            return NULL;
        }
    }
    return line;
}

bool i_stream_last_line_crlf(struct istream *stream)
{
    return stream->real_stream->line_crlf;
}

const unsigned char *
i_stream_get_data(const struct istream *stream, size_t *size_r)
{
    const struct istream_private *_stream = stream->real_stream;

    if (_stream->skip >= _stream->pos) {
        *size_r = 0;
        return NULL;
    }

        *size_r = _stream->pos - _stream->skip;
        return _stream->buffer + _stream->skip;
}

size_t i_stream_get_data_size(const struct istream *stream)
{
    const struct istream_private *_stream = stream->real_stream;

    if (_stream->skip >= _stream->pos)
        return 0;
    else
        return _stream->pos - _stream->skip;
}

unsigned char *i_stream_get_modifiable_data(const struct istream *stream,
                        size_t *size_r)
{
    const struct istream_private *_stream = stream->real_stream;

    if (_stream->skip >= _stream->pos || _stream->w_buffer == NULL) {
        *size_r = 0;
        return NULL;
    }

        *size_r = _stream->pos - _stream->skip;
        return _stream->w_buffer + _stream->skip;
}

int i_stream_read_data(struct istream *stream, const unsigned char **data_r,
               size_t *size_r, size_t threshold)
{
    ssize_t ret = 0;
    bool read_more = FALSE;

    do {
        *data_r = i_stream_get_data(stream, size_r);
        if (*size_r > threshold)
            return 1;

        /* we need more data */
        ret = i_stream_read(stream);
        if (ret > 0)
            read_more = TRUE;
    } while (ret > 0);

    *data_r = i_stream_get_data(stream, size_r);
    if (ret == -2)
        return -2;

    if (ret == 0) {
        /* need to read more */
        i_assert(!stream->blocking);
        return 0;
    }
    if (stream->eof) {
        if (read_more) {
            /* we read at least some new data */
            return 0;
        }
    } else {
        i_assert(stream->stream_errno != 0);
    }
    return -1;
}

void i_stream_compress(struct istream_private *stream)
{
    memmove(stream->w_buffer, stream->w_buffer + stream->skip,
        stream->pos - stream->skip);
    stream->pos -= stream->skip;

    stream->skip = 0;
}

void i_stream_grow_buffer(struct istream_private *stream, size_t bytes)
{
    size_t old_size;

    i_assert(stream->max_buffer_size > 0);

    old_size = stream->buffer_size;

    stream->buffer_size = stream->pos + bytes;
    if (stream->buffer_size <= stream->init_buffer_size)
        stream->buffer_size = stream->init_buffer_size;
    else
        stream->buffer_size = nearest_power(stream->buffer_size);

    if (stream->buffer_size > stream->max_buffer_size)
        stream->buffer_size = stream->max_buffer_size;

    if (stream->buffer_size <= old_size)
        stream->buffer_size = old_size;
    else {
        stream->w_buffer = i_realloc(stream->w_buffer, old_size,
                         stream->buffer_size);
        stream->buffer = stream->w_buffer;
    }
}

bool i_stream_try_alloc(struct istream_private *stream,
            size_t wanted_size, size_t *size_r)
{
    i_assert(wanted_size > 0);

    if (wanted_size > stream->buffer_size - stream->pos) {
        if (stream->skip > 0) {
            /* remove the unused bytes from beginning of buffer */
                        i_stream_compress(stream);
        } else if (stream->max_buffer_size == 0 ||
               stream->buffer_size < stream->max_buffer_size) {
            /* buffer is full - grow it */
            i_stream_grow_buffer(stream, I_STREAM_MIN_SIZE);
        }
    }

    *size_r = stream->buffer_size - stream->pos;
    if (stream->try_alloc_limit > 0 &&
        *size_r > stream->try_alloc_limit)
        *size_r = stream->try_alloc_limit;
    return *size_r > 0;
}

void *i_stream_alloc(struct istream_private *stream, size_t size)
{
    size_t old_size, avail_size;

    i_stream_try_alloc(stream, size, &avail_size);
    if (avail_size < size) {
        old_size = stream->buffer_size;
        stream->buffer_size = nearest_power(stream->pos + size);
        stream->w_buffer = i_realloc(stream->w_buffer, old_size,
                         stream->buffer_size);
        stream->buffer = stream->w_buffer;
        i_stream_try_alloc(stream, size, &avail_size);
        i_assert(avail_size >= size);
    }
    return stream->w_buffer + stream->pos;
}

bool i_stream_add_data(struct istream *_stream, const unsigned char *data,
               size_t size)
{
    struct istream_private *stream = _stream->real_stream;
    size_t size2;

    i_stream_try_alloc(stream, size, &size2);
    if (size > size2)
        return FALSE;

    memcpy(stream->w_buffer + stream->pos, data, size);
    stream->pos += size;
    return TRUE;
}

void i_stream_set_input_pending(struct istream *stream, bool pending)
{
    if (!pending)
        return;

    while (stream->real_stream->parent != NULL) {
        i_assert(stream->real_stream->io == NULL);
        stream = stream->real_stream->parent;
    }
    if (stream->real_stream->io != NULL)
        io_set_pending(stream->real_stream->io);
}

void i_stream_switch_ioloop(struct istream *stream)
{
    do {
        if (stream->real_stream->switch_ioloop != NULL)
            stream->real_stream->switch_ioloop(stream->real_stream);
        stream = stream->real_stream->parent;
    } while (stream != NULL);
}

void i_stream_set_io(struct istream *stream, struct io *io)
{
    while (stream->real_stream->parent != NULL) {
        i_assert(stream->real_stream->io == NULL);
        stream = stream->real_stream->parent;
    }

    i_assert(stream->real_stream->io == NULL);
    stream->real_stream->io = io;
}

void i_stream_unset_io(struct istream *stream, struct io *io)
{
    while (stream->real_stream->parent != NULL) {
        i_assert(stream->real_stream->io == NULL);
        stream = stream->real_stream->parent;
    }

    i_assert(stream->real_stream->io == io);
    stream->real_stream->io = NULL;
}

static void
i_stream_default_set_max_buffer_size(struct iostream_private *stream,
                     size_t max_size)
{
    struct istream_private *_stream = (struct istream_private *)stream;

    _stream->max_buffer_size = max_size;
    if (_stream->parent != NULL)
        i_stream_set_max_buffer_size(_stream->parent, max_size);
}

static void i_stream_default_close(struct iostream_private *stream,
                   bool close_parent)
{
    struct istream_private *_stream = (struct istream_private *)stream;

    if (close_parent && _stream->parent != NULL)
        i_stream_close(_stream->parent);
}

static void i_stream_default_destroy(struct iostream_private *stream)
{
    struct istream_private *_stream = (struct istream_private *)stream;

    i_free(_stream->w_buffer);
    if (_stream->parent != NULL)
        i_stream_unref(&_stream->parent);
}

static void
i_stream_default_seek_seekable(struct istream_private *stream,
                   uoff_t v_offset, bool mark ATTR_UNUSED)
{
    stream->istream.v_offset = v_offset;
    stream->skip = stream->pos = 0;
}

void i_stream_default_seek_nonseekable(struct istream_private *stream,
                       uoff_t v_offset, bool mark ATTR_UNUSED)
{
    size_t available;

    if (stream->istream.v_offset > v_offset)
        i_panic("stream %s doesn't support seeking backwards",
            i_stream_get_name(&stream->istream));

    while (stream->istream.v_offset < v_offset) {
        (void)i_stream_read(&stream->istream);

        available = stream->pos - stream->skip;
        if (available == 0) {
            stream->istream.stream_errno = ESPIPE;
            return;
        }
        if (available <= v_offset - stream->istream.v_offset)
            i_stream_skip(&stream->istream, available);
        else {
            i_stream_skip(&stream->istream,
                      v_offset - stream->istream.v_offset);
        }
    }
}

static int
i_stream_default_stat(struct istream_private *stream, bool exact)
{
    const struct stat *st;

    if (stream->parent == NULL)
        return stream->istream.stream_errno == 0 ? 0 : -1;

    if (i_stream_stat(stream->parent, exact, &st) < 0)
        return -1;
    stream->statbuf = *st;
    if (exact && !stream->stream_size_passthrough) {
        /* exact size is not known, even if parent returned something */
        stream->statbuf.st_size = -1;
    }
    return 0;
}

static int
i_stream_default_get_size(struct istream_private *stream,
              bool exact, uoff_t *size_r)
{
    if (stream->stat(stream, exact) < 0)
        return -1;
    if (stream->statbuf.st_size == -1)
        return 0;

    *size_r = stream->statbuf.st_size;
    return 1;
}

void i_stream_init_parent(struct istream_private *_stream,
              struct istream *parent)
{
    _stream->access_counter = parent->real_stream->access_counter;
    _stream->parent = parent;
    _stream->parent_start_offset = parent->v_offset;
    _stream->parent_expected_offset = parent->v_offset;
    _stream->abs_start_offset = parent->v_offset +
        parent->real_stream->abs_start_offset;
    /* if parent stream is an istream-error, copy the error */
    _stream->istream.stream_errno = parent->stream_errno;
    _stream->istream.eof = parent->eof;
    i_stream_ref(parent);
}

struct istream *
i_stream_create(struct istream_private *_stream, struct istream *parent, int fd)
{
    _stream->fd = fd;
    if (parent != NULL)
        i_stream_init_parent(_stream, parent);
    _stream->istream.real_stream = _stream;

    if (_stream->iostream.close == NULL)
        _stream->iostream.close = i_stream_default_close;
    if (_stream->iostream.destroy == NULL)
        _stream->iostream.destroy = i_stream_default_destroy;
    if (_stream->seek == NULL) {
        _stream->seek = _stream->istream.seekable ?
            i_stream_default_seek_seekable :
            i_stream_default_seek_nonseekable;
    }
    if (_stream->stat == NULL)
        _stream->stat = i_stream_default_stat;
    if (_stream->get_size == NULL)
        _stream->get_size = i_stream_default_get_size;
    if (_stream->iostream.set_max_buffer_size == NULL) {
        _stream->iostream.set_max_buffer_size =
            i_stream_default_set_max_buffer_size;
    }
    if (_stream->init_buffer_size == 0)
        _stream->init_buffer_size = I_STREAM_MIN_SIZE;

    memset(&_stream->statbuf, 0, sizeof(_stream->statbuf));
    _stream->statbuf.st_size = -1;
    _stream->statbuf.st_atime =
        _stream->statbuf.st_mtime =
        _stream->statbuf.st_ctime = ioloop_time;

    io_stream_init(&_stream->iostream);
    return &_stream->istream;
}

struct istream *i_stream_create_error(int stream_errno)
{
    struct istream_private *stream;

    stream = i_new(struct istream_private, 1);
    stream->istream.closed = TRUE;
    stream->istream.readable_fd = FALSE;
    stream->istream.blocking = TRUE;
    stream->istream.seekable = TRUE;
    stream->istream.eof = TRUE;
    stream->istream.stream_errno = stream_errno;
    i_stream_create(stream, NULL, -1);
    i_stream_set_name(&stream->istream, "(error)");
    return &stream->istream;
}

struct istream *
i_stream_create_error_str(int stream_errno, const char *fmt, ...)
{
    struct istream *input;
    va_list args;

    va_start(args, fmt);
    input = i_stream_create_error(stream_errno);
    io_stream_set_verror(&input->real_stream->iostream, fmt, args);
    va_end(args);
    return input;
}