src/lib/istream.c

	istream.c revision 0a0cd45a633112a2ae6aad801c1e6afe53ab95de
/* Copyright (c) 2002-2008 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "ioloop.h"
#include "str.h"
#include "istream-internal.h"

void i_stream_destroy(struct istream **stream)
{
    i_stream_close(*stream);
    i_stream_unref(stream);
}

void i_stream_ref(struct istream *stream)
{
    io_stream_ref(&stream->real_stream->iostream);
}

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

    if (_stream->iostream.refcount == 1) {
        if (_stream->line_str != NULL)
            str_free(&_stream->line_str);
    }
    io_stream_unref(&(*stream)->real_stream->iostream);
    *stream = NULL;
}

#undef i_stream_set_destroy_callback
void i_stream_set_destroy_callback(struct istream *stream,
                   istream_callback_t *callback, void *context)
{
    struct iostream_private *iostream = &stream->real_stream->iostream;

    iostream->destroy_callback = callback;
    iostream->destroy_context = context;
}

int i_stream_get_fd(struct istream *stream)
{
    struct istream_private *_stream = stream->real_stream;

    return _stream->fd;
}

void i_stream_close(struct istream *stream)
{
    io_stream_close(&stream->real_stream->iostream);
    stream->closed = TRUE;

    if (stream->stream_errno == 0)
        stream->stream_errno = ENOENT;
}

void i_stream_set_max_buffer_size(struct istream *stream, size_t max_size)
{
    io_stream_set_max_buffer_size(&stream->real_stream->iostream, max_size);
}

ssize_t i_stream_read(struct istream *stream)
{
    struct istream_private *_stream = stream->real_stream;
    ssize_t ret;

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

    stream->eof = FALSE;
    stream->stream_errno = 0;

    ret = _stream->read(_stream);
    switch (ret) {
    case -2:
        i_assert(_stream->skip != _stream->pos);
        break;
    case -1:
        if (stream->stream_errno != 0) {
            /* error handling should be easier if we now just
               assume the stream is now at EOF */
            stream->eof = TRUE;
        } else {
            i_assert(stream->eof);
        }
        break;
    case 0:
        i_assert(!stream->blocking);
        break;
    }
    return ret;
}

void i_stream_skip(struct istream *stream, uoff_t count)
{
    struct istream_private *_stream = stream->real_stream;
    size_t data_size;

    data_size = _stream->pos - _stream->skip;
    if (count <= data_size) {
        /* within buffer */
        stream->v_offset += count;
        _stream->skip += count;
        return;
    }

    /* have to seek forward */
    count -= data_size;
    _stream->skip = _stream->pos;
    stream->v_offset += data_size;

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

    stream->stream_errno = 0;
    _stream->seek(_stream, stream->v_offset + count, FALSE);
}

static bool i_stream_can_optimize_seek(struct istream *stream)
{
    uoff_t expected_offset;

    if (stream->real_stream->parent == NULL)
        return TRUE;

    /* use the fast route only if the parent stream is at the
       expected offset */
    expected_offset = stream->real_stream->parent_start_offset +
        stream->v_offset - stream->real_stream->skip;
    if (stream->real_stream->parent->v_offset != expected_offset)
        return FALSE;

    return i_stream_can_optimize_seek(stream->real_stream->parent);
}

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);
        return;
    }

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

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

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);
}

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);
}

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

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

    return _stream->stat(_stream, exact);
}

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;
}

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;
    else
        end = i;

    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);
    }

    i++;
    stream->istream.v_offset += i - stream->skip;
    stream->skip = i;
    return ret;
}

char *i_stream_next_line(struct istream *stream)
{
    struct istream_private *_stream = stream->real_stream;
    char *ret_buf;
        size_t i;

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

    if (unlikely(_stream->w_buffer == NULL)) {
        i_error("i_stream_next_line() called for unmodifiable stream");
        return NULL;
    }

    /* @UNSAFE */
    ret_buf = NULL;
    for (i = _stream->skip; i < _stream->pos; i++) {
        if (_stream->buffer[i] == 10) {
            /* got it */
            ret_buf = i_stream_next_line_finish(_stream, i);
                        break;
        }
    }

        return ret_buf;
}

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

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

        if (i_stream_read(stream) <= 0)
            return NULL;
    }
    return line;
}

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;
}

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;

    old_size = stream->buffer_size;

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

    if (stream->max_buffer_size > 0 &&
        stream->buffer_size > stream->max_buffer_size)
        stream->buffer_size = stream->max_buffer_size;

    stream->buffer = stream->w_buffer =
        i_realloc(stream->w_buffer, old_size, stream->buffer_size);
}

bool i_stream_get_buffer_space(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);
        }
    }

    if (size_r != NULL)
        *size_r = stream->buffer_size - stream->pos;
    return stream->pos != stream->buffer_size;
}

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;

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

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

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;
}

static const struct stat *
i_stream_default_stat(struct istream_private *stream, bool exact ATTR_UNUSED)
{
    return &stream->statbuf;
}

struct istream *
i_stream_create(struct istream_private *_stream, struct istream *parent, int fd)
{
    _stream->fd = fd;
    if (parent != NULL) {
        _stream->parent = parent;
        _stream->parent_start_offset = parent->v_offset;
        _stream->abs_start_offset = parent->v_offset +
            parent->real_stream->abs_start_offset;
    }
    _stream->istream.real_stream = _stream;

    if (_stream->stat == NULL)
        _stream->stat = i_stream_default_stat;
    if (_stream->iostream.set_max_buffer_size == NULL) {
        _stream->iostream.set_max_buffer_size =
            i_stream_default_set_max_buffer_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;
}

#ifdef STREAM_TEST
/* gcc istream.c -o teststream liblib.a -Wall -DHAVE_CONFIG_H -DSTREAM_TEST -g */

#include <fcntl.h>
#include <unistd.h>
#include "ostream.h"

#define BUF_VALUE(offset) \
        (((offset) % 256) ^ ((offset) / 256))

static void check_buffer(const unsigned char *data, size_t size, size_t offset)
{
    size_t i;

    for (i = 0; i < size; i++)
        i_assert(data[i] == BUF_VALUE(i+offset));
}

int main(void)
{
    struct istream *input, *l_input;
    struct ostream *output1, *output2;
    int i, fd1, fd2;
    unsigned char buf[1024];
    const unsigned char *data;
    size_t size;

    lib_init();

    fd1 = open("teststream.1", O_RDWR | O_CREAT | O_TRUNC, 0600);
    if (fd1 < 0)
        i_fatal("open() failed: %m");
    fd2 = open("teststream.2", O_RDWR | O_CREAT | O_TRUNC, 0600);
    if (fd2 < 0)
        i_fatal("open() failed: %m");

    /* write initial data */
    for (i = 0; i < sizeof(buf); i++)
        buf[i] = BUF_VALUE(i);
    write(fd1, buf, sizeof(buf));

    /* test reading */
    input = i_stream_create_fd(fd1, 512, FALSE);
    i_assert(i_stream_get_size(input) == sizeof(buf));

    i_assert(i_stream_read_data(input, &data, &size, 0) > 0);
    i_assert(size == 512);
    check_buffer(data, size, 0);

    i_stream_seek(input, 256);
    i_assert(i_stream_read_data(input, &data, &size, 0) > 0);
    i_assert(size == 512);
    check_buffer(data, size, 256);

    i_stream_seek(input, 0);
    i_assert(i_stream_read_data(input, &data, &size, 512) == -2);
    i_assert(size == 512);
    check_buffer(data, size, 0);

    i_stream_skip(input, 900);
    i_assert(i_stream_read_data(input, &data, &size, 0) > 0);
    i_assert(size == sizeof(buf) - 900);
    check_buffer(data, size, 900);

    /* test moving data */
    output1 = o_stream_create_fd(fd1, 512, FALSE);
    output2 = o_stream_create_fd(fd2, 512, FALSE);

    i_stream_seek(input, 1); size = sizeof(buf)-1;
    i_assert(o_stream_send_istream(output2, input) == size);
    o_stream_flush(output2);

    lseek(fd2, 0, SEEK_SET);
    i_assert(read(fd2, buf, sizeof(buf)) == size);
    check_buffer(buf, size, 1);

    i_stream_seek(input, 0);
    o_stream_seek(output1, sizeof(buf));
    i_assert(o_stream_send_istream(output1, input) == sizeof(buf));

    /* test moving with limits */
    l_input = i_stream_create_limit(input, sizeof(buf)/2, 512);
    i_stream_seek(l_input, 0);
    o_stream_seek(output1, 10);
    i_assert(o_stream_send_istream(output1, l_input) == 512);

    i_stream_set_max_buffer_size(input, sizeof(buf));

    i_stream_seek(input, 0);
    i_assert(i_stream_read_data(input, &data, &size, sizeof(buf)-1) > 0);
    i_assert(size == sizeof(buf));
    check_buffer(data, 10, 0);
    check_buffer(data + 10, 512, sizeof(buf)/2);
    check_buffer(data + 10 + 512,
             size - (10 + 512), 10 + 512);

    /* reading within limits */
    i_stream_seek(l_input, 0);
    i_assert(i_stream_read_data(l_input, &data, &size, 511) > 0);
    i_assert(size == 512);
    i_assert(i_stream_read_data(l_input, &data, &size, 512) == -2);
    i_assert(size == 512);
    i_stream_skip(l_input, 511);
    i_assert(i_stream_read_data(l_input, &data, &size, 0) > 0);
    i_assert(size == 1);
    i_stream_skip(l_input, 1);
    i_assert(i_stream_read_data(l_input, &data, &size, 0) == -1);
    i_assert(size == 0);

    unlink("teststream.1");
    unlink("teststream.2");
    return 0;
}
#endif