src/lib/istream-hash.c

	istream-hash.c revision 25fb397382c6f7d39bfeee85774e7675f02bfb3c
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen/* Copyright (c) 2013-2015 Dovecot authors, see the included COPYING file */
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen#include "lib.h"
1e21e6be70994b1aa9e52ca0e2f51afefca6d0dfTimo Sirainen#include "hash-method.h"
3b94ff5951db4d4eddb7a80ed4e3f61207202635Timo Sirainen#include "istream-private.h"
66d2db642fe24d555d113ba463e446b038d476efTimo Sirainen#include "istream-hash.h"
66d2db642fe24d555d113ba463e446b038d476efTimo Sirainen
22535a9e685e29214082878e37a267157044618eTimo Sirainenstruct hash_istream {
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen    struct istream_private istream;
1f1e81aab38d833d1c9cdc244c91fd762e0080d4Timo Sirainen
1f1e81aab38d833d1c9cdc244c91fd762e0080d4Timo Sirainen    const struct hash_method *method;
66d2db642fe24d555d113ba463e446b038d476efTimo Sirainen    void *hash_context;
66d2db642fe24d555d113ba463e446b038d476efTimo Sirainen    uoff_t high_offset;
66d2db642fe24d555d113ba463e446b038d476efTimo Sirainen};
66d2db642fe24d555d113ba463e446b038d476efTimo Sirainen
08aea01ef9a9d20703e0fcf8618e6195c0037a44Timo Sirainenstatic ssize_t
25757faf029c369a8318349dafe952e2358df1d8Timo Siraineni_stream_hash_read(struct istream_private *stream)
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen{
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen    struct hash_istream *hstream = (struct hash_istream *)stream;
3b94ff5951db4d4eddb7a80ed4e3f61207202635Timo Sirainen    const unsigned char *data;
66d2db642fe24d555d113ba463e446b038d476efTimo Sirainen    size_t size;
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen    uoff_t skip;
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen    ssize_t ret;
12aad74464367f7e8be11eafe1af985bf7b1adecTimo Sirainen
12aad74464367f7e8be11eafe1af985bf7b1adecTimo Sirainen    i_stream_seek(stream->parent, stream->parent_start_offset +
12aad74464367f7e8be11eafe1af985bf7b1adecTimo Sirainen              stream->istream.v_offset);
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen    ret = i_stream_read_copy_from_parent(&stream->istream);
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen    if (ret > 0 && hstream->hash_context != NULL) {
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen        data = i_stream_get_data(&stream->istream, &size);
1e21e6be70994b1aa9e52ca0e2f51afefca6d0dfTimo Sirainen        i_assert((size_t)ret <= size);
1e21e6be70994b1aa9e52ca0e2f51afefca6d0dfTimo Sirainen
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen        i_assert(stream->istream.v_offset <= hstream->high_offset);
        skip = hstream->high_offset - stream->istream.v_offset;
        if (skip < (size_t)size) {
            hstream->high_offset += (size-skip);
            hstream->method->loop(hstream->hash_context,
                          data+skip, size-skip);
        }
    } else if (ret < 0) {
        /* we finished hashing it. don't access it anymore, because
           the memory pointed by the hash may be freed before the
           istream itself */
        hstream->hash_context = NULL;
    }
    return ret;
}

static void
i_stream_hash_seek(struct istream_private *stream,
           uoff_t v_offset, bool mark ATTR_UNUSED)
{
    struct hash_istream *hstream = (struct hash_istream *)stream;

    if (hstream->hash_context != NULL) {
        io_stream_set_error(&stream->iostream,
            "Seeking not supported before hashing is finished");
        stream->istream.stream_errno = ESPIPE;
    }
    stream->istream.v_offset = v_offset;
    stream->skip = stream->pos = 0;
}

struct istream *
i_stream_create_hash(struct istream *input, const struct hash_method *method,
             void *hash_context)
{
    struct hash_istream *hstream;

    hstream = i_new(struct hash_istream, 1);
    hstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
    hstream->istream.stream_size_passthrough = TRUE;

    hstream->istream.read = i_stream_hash_read;
    hstream->istream.seek = i_stream_hash_seek;

    hstream->istream.istream.readable_fd = input->readable_fd;
    hstream->istream.istream.blocking = input->blocking;
    hstream->istream.istream.seekable = input->seekable;

    hstream->method = method;
    hstream->hash_context = hash_context;
    return i_stream_create(&hstream->istream, input,
                   i_stream_get_fd(input));
}