index/maildir/maildir-mail.c

	maildir-mail.c revision 2d01cc1880cf2afd4fb1c8ad7fa6ce78e562e71e
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen/* Copyright (c) 2003-2011 Dovecot authors, see the included COPYING file */
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include "lib.h"
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include "istream.h"
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include "index-mail.h"
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include "maildir-storage.h"
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include "maildir-filename.h"
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include "maildir-uidlist.h"
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include "maildir-sync.h"
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include <stdlib.h>
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include <fcntl.h>
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include <unistd.h>
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen#include <sys/stat.h>
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainenstruct maildir_open_context {
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    int fd;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    char *path;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen};
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainenstatic int
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainendo_open(struct maildir_mailbox *mbox, const char *path,
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    struct maildir_open_context *ctx)
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen{
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    ctx->fd = open(path, O_RDONLY);
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    if (ctx->fd != -1) {
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        ctx->path = i_strdup(path);
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        return 1;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    }
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    if (errno == ENOENT)
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        return 0;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    if (errno == EACCES) {
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        mail_storage_set_critical(&mbox->storage->storage, "%s",
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen            mail_error_eacces_msg("open", path));
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    } else {
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        mail_storage_set_critical(&mbox->storage->storage,
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen                      "open(%s) failed: %m", path);
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    }
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    return -1;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen}
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainenstatic int
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainendo_stat(struct maildir_mailbox *mbox, const char *path, struct stat *st)
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen{
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    if (stat(path, st) == 0)
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        return 1;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    if (errno == ENOENT)
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        return 0;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    if (errno == EACCES) {
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        mail_storage_set_critical(&mbox->storage->storage, "%s",
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen            mail_error_eacces_msg("stat", path));
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    } else {
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        mail_storage_set_critical(&mbox->storage->storage,
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen                      "stat(%s) failed: %m", path);
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    }
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    return -1;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen}
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainenstatic struct istream *
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainenmaildir_open_mail(struct maildir_mailbox *mbox, struct mail *mail,
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen          bool *deleted_r)
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen{
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    struct istream *input;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    const char *path;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    struct maildir_open_context ctx;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    *deleted_r = FALSE;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    ctx.fd = -1;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    ctx.path = NULL;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    mail->transaction->stats.open_lookup_count++;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    if (!mail->saving) {
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        if (maildir_file_do(mbox, mail->uid, do_open, &ctx) < 0)
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen            return NULL;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    } else {
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        path = maildir_save_file_get_path(mail->transaction, mail->seq);
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        if (do_open(mbox, path, &ctx) <= 0)
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen            return NULL;
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    }
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen    if (ctx.fd == -1) {
48acc31adebfdd4e4945ee76e1f5259e4b1b6fffTimo Sirainen        *deleted_r = TRUE;
        return NULL;
    }

    input = i_stream_create_fd(ctx.fd, 0, TRUE);
    if (input->stream_errno == EISDIR) {
        i_stream_destroy(&input);
        if (maildir_lose_unexpected_dir(&mbox->storage->storage,
                        ctx.path) >= 0)
            *deleted_r = TRUE;
    } else {
        i_stream_set_name(input, ctx.path);
        index_mail_set_read_buffer_size(mail, input);
    }
    i_free(ctx.path);
    return input;
}

static int maildir_mail_stat(struct mail *mail, struct stat *st)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)mail->box;
    struct index_mail *imail = (struct index_mail *)mail;
    const struct stat *stp;
    const char *path;
    int ret;

    if (mail->lookup_abort == MAIL_LOOKUP_ABORT_NOT_IN_CACHE)
        return mail_set_aborted(mail);

    if (imail->data.access_part != 0 &&
        imail->data.stream == NULL) {
        /* we're going to open the mail anyway */
        struct istream *input;

        (void)mail_get_stream(mail, NULL, NULL, &input);
    }

    if (imail->data.stream != NULL) {
        mail->transaction->stats.fstat_lookup_count++;
        stp = i_stream_stat(imail->data.stream, FALSE);
        if (stp == NULL)
            return -1;
        *st = *stp;
    } else if (!mail->saving) {
        mail->transaction->stats.stat_lookup_count++;
        ret = maildir_file_do(mbox, mail->uid, do_stat, st);
        if (ret <= 0) {
            if (ret == 0)
                mail_set_expunged(mail);
            return -1;
        }
    } else {
        mail->transaction->stats.stat_lookup_count++;
        path = maildir_save_file_get_path(mail->transaction, mail->seq);
        if (stat(path, st) < 0) {
            mail_storage_set_critical(mail->box->storage,
                          "stat(%s) failed: %m", path);
            return -1;
        }
    }
    return 0;
}

static int maildir_mail_get_received_date(struct mail *_mail, time_t *date_r)
{
    struct index_mail *mail = (struct index_mail *)_mail;
    struct index_mail_data *data = &mail->data;
    struct stat st;

    if (index_mail_get_received_date(_mail, date_r) == 0)
        return 0;

    if (maildir_mail_stat(_mail, &st) < 0)
        return -1;

    *date_r = data->received_date = st.st_mtime;
    return 0;
}

static int maildir_mail_get_save_date(struct mail *_mail, time_t *date_r)
{
    struct index_mail *mail = (struct index_mail *)_mail;
    struct index_mail_data *data = &mail->data;
    struct stat st;

    if (index_mail_get_save_date(_mail, date_r) == 0)
        return 0;

    if (maildir_mail_stat(_mail, &st) < 0)
        return -1;

    *date_r = data->save_date = st.st_ctime;
    return 0;
}

static int
maildir_mail_get_fname(struct maildir_mailbox *mbox, struct mail *mail,
               const char **fname_r)
{
    enum maildir_uidlist_rec_flag flags;
    struct mail_index_view *view;
    uint32_t seq;
    bool exists;
    int ret;

    ret = maildir_sync_lookup(mbox, mail->uid, &flags, fname_r);
    if (ret != 0)
        return ret;

    /* file exists in index file, but not in dovecot-uidlist anymore. */
    mail_set_expunged(mail);

    /* one reason this could happen is if we delayed opening
       dovecot-uidlist and we're trying to open a mail that got recently
       expunged. Let's test this theory first: */
    (void)mail_index_refresh(mbox->box.index);
    view = mail_index_view_open(mbox->box.index);
    exists = mail_index_lookup_seq(view, mail->uid, &seq);
    mail_index_view_close(&view);

    if (exists) {
        /* the message still exists in index. this means there's some
           kind of a desync, which doesn't get fixed if cur/ mtime is
           the same as in index. fix this by forcing a resync. */
        (void)maildir_storage_sync_force(mbox, mail->uid);
    }
    return 0;
}

static int maildir_get_pop3_state(struct index_mail *mail)
{
    struct mailbox *box = mail->mail.mail.box;
    struct index_mailbox_context *ibox = INDEX_STORAGE_CONTEXT(box);
    const struct mail_cache_field *fields;
    unsigned int i, count, psize_idx, vsize_idx;
    enum mail_cache_decision_type dec, vsize_dec;
    enum mail_fetch_field allowed_pop3_fields;
    bool not_pop3_only = FALSE;

    if (mail->pop3_state_set)
        return mail->pop3_state;

    /* if this mail itself has non-pop3 fields we know we're not
       pop3-only */
    allowed_pop3_fields = MAIL_FETCH_FLAGS | MAIL_FETCH_STREAM_HEADER |
        MAIL_FETCH_STREAM_BODY | MAIL_FETCH_UIDL_FILE_NAME |
        MAIL_FETCH_VIRTUAL_SIZE;

    if (mail->wanted_headers != NULL ||
        (mail->wanted_fields & ~allowed_pop3_fields) != 0)
        not_pop3_only = TRUE;

    /* get vsize decisions */
    psize_idx = ibox->cache_fields[MAIL_CACHE_PHYSICAL_FULL_SIZE].idx;
    vsize_idx = ibox->cache_fields[MAIL_CACHE_VIRTUAL_FULL_SIZE].idx;
    if (not_pop3_only) {
        vsize_dec = mail_cache_field_get_decision(box->cache,
                              vsize_idx);
        vsize_dec &= ~MAIL_CACHE_DECISION_FORCED;
    } else {
        /* also check if there are any non-[pv]size cached fields */
        vsize_dec = MAIL_CACHE_DECISION_NO;
        fields = mail_cache_register_get_list(box->cache,
                              pool_datastack_create(),
                              &count);
        for (i = 0; i < count; i++) {
            dec = fields[i].decision & ~MAIL_CACHE_DECISION_FORCED;
            if (fields[i].idx == vsize_idx)
                vsize_dec = dec;
            else if (dec != MAIL_CACHE_DECISION_NO &&
                 fields[i].idx != psize_idx)
                not_pop3_only = TRUE;
        }
    }

    if (!not_pop3_only) {
        /* either nothing is cached, or only vsize is cached. */
        mail->pop3_state = 1;
    } else if (vsize_dec != MAIL_CACHE_DECISION_YES &&
           (box->flags & MAILBOX_FLAG_POP3_SESSION) == 0) {
        /* if virtual size isn't cached permanently,
           POP3 isn't being used */
        mail->pop3_state = -1;
    } else {
        /* possibly a mixed pop3/imap */
        mail->pop3_state = 0;
    }
    mail->pop3_state_set = TRUE;
    return mail->pop3_state;
}

static int maildir_quick_size_lookup(struct index_mail *mail, bool vsize,
                     uoff_t *size_r)
{
    struct mail *_mail = &mail->mail.mail;
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)_mail->box;
    enum maildir_uidlist_rec_ext_key key;
    const char *path, *fname, *value;

    if (!_mail->saving) {
        if (maildir_mail_get_fname(mbox, _mail, &fname) <= 0)
            return -1;
    } else {
        path = maildir_save_file_get_path(_mail->transaction,
                          _mail->seq);
        fname = strrchr(path, '/');
        fname = fname != NULL ? fname + 1 : path;
    }

    /* size can be included in filename */
    if (maildir_filename_get_size(fname,
                      vsize ? MAILDIR_EXTRA_VIRTUAL_SIZE :
                      MAILDIR_EXTRA_FILE_SIZE,
                      size_r))
        return 1;

    /* size can be included in uidlist entry */
    if (!_mail->saving) {
        key = vsize ? MAILDIR_UIDLIST_REC_EXT_VSIZE :
            MAILDIR_UIDLIST_REC_EXT_PSIZE;
        value = maildir_uidlist_lookup_ext(mbox->uidlist, _mail->uid,
                           key);
        if (value != NULL && str_to_uoff(value, size_r) == 0)
            return 1;
    }
    return 0;
}

static void
maildir_handle_size_caching(struct index_mail *mail, bool quick_check,
                bool vsize)
{
    struct mailbox *box = mail->mail.mail.box;
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)box;
    enum mail_fetch_field field;
    uoff_t size;
    int pop3_state;

    field = vsize ? MAIL_FETCH_VIRTUAL_SIZE : MAIL_FETCH_PHYSICAL_SIZE;
    if ((mail->data.dont_cache_fetch_fields & field) != 0)
        return;

    if (quick_check && maildir_quick_size_lookup(mail, vsize, &size) > 0) {
        /* already in filename / uidlist. don't add it anywhere,
           including to the uidlist if it's already in filename.
           do some extra checks here to catch potential cache bugs. */
        if (vsize && mail->data.virtual_size != size) {
            mail_cache_set_corrupted(box->cache,
                "Corrupted virtual size for uid=%u: "
                "%"PRIuUOFF_T" != %"PRIuUOFF_T,
                mail->mail.mail.uid,
                mail->data.virtual_size, size);
            mail->data.virtual_size = size;
        } else if (!vsize && mail->data.physical_size != size) {
            mail_cache_set_corrupted(box->cache,
                "Corrupted physical size for uid=%u: "
                "%"PRIuUOFF_T" != %"PRIuUOFF_T,
                mail->mail.mail.uid,
                mail->data.physical_size, size);
            mail->data.physical_size = size;
        }
        mail->data.dont_cache_fetch_fields |= field;
        return;
    }

    /* 1 = pop3-only, 0 = mixed, -1 = no pop3 */
    pop3_state = maildir_get_pop3_state(mail);
    if (pop3_state >= 0 && mail->mail.mail.uid != 0) {
        /* if size is wanted permanently, store it to uidlist
           so that in case cache file gets lost we can get it quickly */
        mail->data.dont_cache_fetch_fields |= field;
        size = vsize ? mail->data.virtual_size :
            mail->data.physical_size;
        maildir_uidlist_set_ext(mbox->uidlist, mail->mail.mail.uid,
                    vsize ? MAILDIR_UIDLIST_REC_EXT_VSIZE :
                    MAILDIR_UIDLIST_REC_EXT_PSIZE,
                    dec2str(size));
    }
}

static int maildir_mail_get_virtual_size(struct mail *_mail, uoff_t *size_r)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)_mail->box;
    struct index_mail *mail = (struct index_mail *)_mail;
    struct index_mail_data *data = &mail->data;
    struct message_size hdr_size, body_size;
    struct istream *input;
    uoff_t old_offset;

    if (maildir_uidlist_is_read(mbox->uidlist) ||
        (_mail->box->flags & MAILBOX_FLAG_POP3_SESSION) != 0) {
        /* try to get the size from uidlist. this is especially useful
           with pop3 to avoid unnecessarily opening the cache file. */
        if (maildir_quick_size_lookup(mail, TRUE,
                          &data->virtual_size) < 0)
            return -1;
    }

    if (data->virtual_size == (uoff_t)-1) {
        if (index_mail_get_cached_virtual_size(mail, size_r)) {
            i_assert(mail->data.virtual_size != (uoff_t)-1);
            maildir_handle_size_caching(mail, TRUE, TRUE);
            return 0;
        }
        if (maildir_quick_size_lookup(mail, TRUE,
                          &data->virtual_size) < 0)
            return -1;
    }
    if (data->virtual_size != (uoff_t)-1) {
        data->dont_cache_fetch_fields |= MAIL_FETCH_VIRTUAL_SIZE;
        *size_r = data->virtual_size;
        return 0;
    }

    /* fallback to reading the file */
    old_offset = data->stream == NULL ? 0 : data->stream->v_offset;
    if (mail_get_stream(_mail, &hdr_size, &body_size, &input) < 0)
        return -1;
    i_stream_seek(data->stream, old_offset);

    maildir_handle_size_caching(mail, FALSE, TRUE);
    *size_r = data->virtual_size;
    return 0;
}

static int maildir_mail_get_physical_size(struct mail *_mail, uoff_t *size_r)
{
    struct index_mail *mail = (struct index_mail *)_mail;
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)_mail->box;
    struct index_mail_data *data = &mail->data;
    struct stat st;
    const char *path;
    int ret;

    if (maildir_uidlist_is_read(mbox->uidlist) ||
        (_mail->box->flags & MAILBOX_FLAG_POP3_SESSION) != 0) {
        /* try to get the size from uidlist (see virtual size above) */
        if (maildir_quick_size_lookup(mail, FALSE,
                          &data->physical_size) < 0)
            return -1;
    }

    if (data->physical_size == (uoff_t)-1) {
        if (index_mail_get_physical_size(_mail, size_r) == 0) {
            i_assert(mail->data.physical_size != (uoff_t)-1);
            maildir_handle_size_caching(mail, TRUE, FALSE);
            return 0;
        }
        if (maildir_quick_size_lookup(mail, FALSE,
                          &data->physical_size) < 0)
            return -1;
    }
    if (data->physical_size != (uoff_t)-1) {
        data->dont_cache_fetch_fields |= MAIL_FETCH_PHYSICAL_SIZE;
        *size_r = data->physical_size;
        return 0;
    }

    if (!_mail->saving) {
        ret = maildir_file_do(mbox, _mail->uid, do_stat, &st);
        if (ret <= 0) {
            if (ret == 0)
                mail_set_expunged(_mail);
            return -1;
        }
    } else {
        /* saved mail which hasn't been committed yet */
        path = maildir_save_file_get_path(_mail->transaction,
                          _mail->seq);
        if (stat(path, &st) < 0) {
            mail_storage_set_critical(_mail->box->storage,
                          "stat(%s) failed: %m", path);
            return -1;
        }
    }

    data->physical_size = st.st_size;
    maildir_handle_size_caching(mail, FALSE, FALSE);
    *size_r = st.st_size;
    return 0;
}

static int
maildir_mail_get_special(struct mail *_mail, enum mail_fetch_field field,
             const char **value_r)
{
    struct index_mail *mail = (struct index_mail *)_mail;
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)_mail->box;
    const char *path, *fname = NULL, *end, *guid, *uidl, *order;

    switch (field) {
    case MAIL_FETCH_GUID:
        /* use GUID from uidlist if it exists */
        i_assert(!_mail->saving);

        /* first make sure that we have a refreshed uidlist */
        if (maildir_mail_get_fname(mbox, _mail, &fname) <= 0)
            return -1;

        guid = maildir_uidlist_lookup_ext(mbox->uidlist, _mail->uid,
                          MAILDIR_UIDLIST_REC_EXT_GUID);
        if (guid != NULL) {
            if (*guid != '\0') {
                *value_r = p_strdup(mail->data_pool, guid);
                return 0;
            }

            mail_storage_set_critical(_mail->box->storage,
                "Maildir %s: Corrupted dovecot-uidlist: "
                "UID %u had empty GUID, clearing it",
                mailbox_get_path(_mail->box), _mail->uid);
            maildir_uidlist_set_ext(mbox->uidlist, _mail->uid,
                MAILDIR_UIDLIST_REC_EXT_GUID, NULL);
        }

        /* default to base filename: */
    case MAIL_FETCH_UIDL_FILE_NAME:
        if (mail->data.guid != NULL) {
            *value_r = mail->data.guid;
            return 0;
        }
        if (fname != NULL) {
            /* we came here from MAIL_FETCH_GUID,
               avoid a second lookup */
        } else if (!_mail->saving) {
            if (maildir_mail_get_fname(mbox, _mail, &fname) <= 0)
                return -1;
        } else {
            path = maildir_save_file_get_path(_mail->transaction,
                              _mail->seq);
            fname = strrchr(path, '/');
            fname = fname != NULL ? fname + 1 : path;
        }
        end = strchr(fname, MAILDIR_INFO_SEP);
        mail->data.guid = end == NULL ?
            p_strdup(mail->data_pool, fname) :
            p_strdup_until(mail->data_pool, fname, end);
        *value_r = mail->data.guid;
        return 0;
    case MAIL_FETCH_UIDL_BACKEND:
        uidl = maildir_uidlist_lookup_ext(mbox->uidlist, _mail->uid,
                    MAILDIR_UIDLIST_REC_EXT_POP3_UIDL);
        if (uidl == NULL) {
            /* use the default */
            *value_r = "";
        } else if (*uidl == '\0') {
            /* special optimization case: use the base file name */
            return maildir_mail_get_special(_mail,
                    MAIL_FETCH_UIDL_FILE_NAME, value_r);
        } else {
            *value_r = p_strdup(mail->data_pool, uidl);
        }
        return 0;
    case MAIL_FETCH_POP3_ORDER:
        order = maildir_uidlist_lookup_ext(mbox->uidlist, _mail->uid,
                    MAILDIR_UIDLIST_REC_EXT_POP3_ORDER);
        if (order == NULL) {
            *value_r = "";
        } else {
            *value_r = p_strdup(mail->data_pool, order);
        }
        return 0;
    default:
        return index_mail_get_special(_mail, field, value_r);
    }
}

static int maildir_mail_get_stream(struct mail *_mail,
                   struct message_size *hdr_size,
                   struct message_size *body_size,
                   struct istream **stream_r)
{
    struct index_mail *mail = (struct index_mail *)_mail;
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)_mail->box;
    struct index_mail_data *data = &mail->data;
    bool deleted;

    if (data->stream == NULL) {
        data->stream = maildir_open_mail(mbox, _mail, &deleted);
        if (data->stream == NULL) {
            if (deleted)
                mail_set_expunged(_mail);
            return -1;
        }
        if (mail->mail.v.istream_opened != NULL) {
            if (mail->mail.v.istream_opened(_mail,
                            &data->stream) < 0)
                return -1;
        }
    }

    return index_mail_init_stream(mail, hdr_size, body_size, stream_r);
}

static void maildir_update_pop3_uidl(struct mail *_mail, const char *uidl)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)_mail->box;
    const char *fname;

    if (maildir_mail_get_special(_mail, MAIL_FETCH_UIDL_FILE_NAME,
                     &fname) == 0 &&
        strcmp(uidl, fname) == 0) {
        /* special case optimization: empty UIDL means the same
           as base filename */
        uidl = "";
    }

    maildir_uidlist_set_ext(mbox->uidlist, _mail->uid,
                MAILDIR_UIDLIST_REC_EXT_POP3_UIDL, uidl);
}

static void maildir_mail_set_cache_corrupted(struct mail *_mail,
                         enum mail_fetch_field field)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)_mail->box;
    enum maildir_uidlist_rec_flag flags;
    const char *fname;
    uoff_t size;
    int ret;

    if (field == MAIL_FETCH_VIRTUAL_SIZE) {
        /* make sure it gets removed from uidlist.
           if it's in file name, we can't really do more than log it. */
        ret = maildir_sync_lookup(mbox, _mail->uid, &flags, &fname);
        if (ret <= 0)
            return;
        if (maildir_filename_get_size(fname, MAILDIR_EXTRA_VIRTUAL_SIZE,
                          &size)) {
            const char *subdir =
                (flags & MAILDIR_UIDLIST_REC_FLAG_NEW_DIR) != 0 ?
                "new" : "cur";
            mail_storage_set_critical(_mail->box->storage,
                "Maildir filename has wrong W value: %s/%s/%s",
                mailbox_get_path(&mbox->box), subdir, fname);
        } else if (maildir_uidlist_lookup_ext(mbox->uidlist, _mail->uid,
                MAILDIR_UIDLIST_REC_EXT_VSIZE) != NULL) {
            maildir_uidlist_set_ext(mbox->uidlist, _mail->uid,
                        MAILDIR_UIDLIST_REC_EXT_VSIZE,
                        NULL);
        }
    }
    index_mail_set_cache_corrupted(_mail, field);
}

struct mail_vfuncs maildir_mail_vfuncs = {
    index_mail_close,
    index_mail_free,
    index_mail_set_seq,
    index_mail_set_uid,
    index_mail_set_uid_cache_updates,
    index_mail_prefetch,

    index_mail_get_flags,
    index_mail_get_keywords,
    index_mail_get_keyword_indexes,
    index_mail_get_modseq,
    index_mail_get_parts,
    index_mail_get_date,
    maildir_mail_get_received_date,
    maildir_mail_get_save_date,
    maildir_mail_get_virtual_size,
    maildir_mail_get_physical_size,
    index_mail_get_first_header,
    index_mail_get_headers,
    index_mail_get_header_stream,
    maildir_mail_get_stream,
    maildir_mail_get_special,
    index_mail_get_real_mail,
    index_mail_update_flags,
    index_mail_update_keywords,
    index_mail_update_modseq,
    maildir_update_pop3_uidl,
    index_mail_expunge,
    index_mail_parse,
    maildir_mail_set_cache_corrupted,
    index_mail_opened
};