src/lib-index/mail-index-transaction.c

	mail-index-transaction.c revision 3127020d0ae64cd75bb428bdee42391376b9dd74
/* Copyright (C) 2003-2004 Timo Sirainen */

/* Inside transaction we keep messages stored in sequences in uid fields.
   Before they're written to transaction log the sequences are changed to
   UIDs. This is because we're able to compress sequence ranges better. */

#include "lib.h"
#include "buffer.h"
#include "mail-index-view-private.h"
#include "mail-transaction-log.h"
#include "mail-cache-private.h"
#include "mail-index-transaction-private.h"

#include <stddef.h>
#include <stdlib.h>

struct mail_index_transaction *
mail_index_transaction_begin(struct mail_index_view *view,
                 int hide, int external)
{
    struct mail_index_transaction *t;

    /* don't allow syncing view while there's ongoing transactions */
    mail_index_view_transaction_ref(view);
    mail_index_view_ref(view);

    t = i_new(struct mail_index_transaction, 1);
    t->refcount = 1;
    t->view = view;
    t->hide_transaction = hide;
    t->external = external;
    t->first_new_seq = mail_index_view_get_messages_count(t->view)+1;

    if (view->syncing) {
        /* transaction view cannot work if new records are being added
           in two places. make sure it doesn't happen. */
        t->no_appends = TRUE;
    }

    return t;
}

static void mail_keyword_transaction_free(struct mail_keyword_transaction *kt)
{
    struct mail_keyword_transaction **p;

    for (p = &kt->keywords->kt; *p != NULL; p = &(*p)->next) {
        if (*p == kt) {
            *p = kt->next;
            break;
        }
    }

    if (*p == NULL) {
        /* no transactions left, free mail_keywords */
        i_assert(kt->keywords->kt == NULL);
        i_free(kt->keywords);
    }

    if (kt->messages != NULL)
        buffer_free(kt->messages);
    i_free(kt);
}

static void mail_index_transaction_free(struct mail_index_transaction *t)
{
    buffer_t **recs;
    size_t i, size;

    if (t->ext_rec_updates != NULL) {
        recs = buffer_get_modifyable_data(t->ext_rec_updates, &size);
        size /= sizeof(*recs);

        for (i = 0; i < size; i++) {
            if (recs[i] != NULL)
                buffer_free(recs[i]);
        }
        buffer_free(t->ext_rec_updates);
    }

    if (t->keyword_updates != NULL) {
        struct mail_keyword_transaction **kt;

        kt = buffer_get_modifyable_data(t->keyword_updates, &size);
        size /= sizeof(*kt);

        for (i = 0; i < size; i++)
            mail_keyword_transaction_free(kt[i]);
        buffer_free(t->keyword_updates);
    }

    if (t->appends != NULL)
        buffer_free(t->appends);
    if (t->expunges != NULL)
        buffer_free(t->expunges);
    if (t->updates != NULL)
        buffer_free(t->updates);
    if (t->ext_resizes != NULL)
        buffer_free(t->ext_resizes);
    if (t->ext_resets != NULL)
        buffer_free(t->ext_resets);

    mail_index_view_transaction_unref(t->view);
    mail_index_view_close(t->view);
    i_free(t);
}

void mail_index_transaction_ref(struct mail_index_transaction *t)
{
    t->refcount++;
}

void mail_index_transaction_unref(struct mail_index_transaction *t)
{
    if (--t->refcount == 0)
        mail_index_transaction_free(t);
}

static void
mail_index_buffer_convert_to_uids(struct mail_index_transaction *t,
                  buffer_t *buf, size_t record_size, int range)
{
        struct mail_index_view *view = t->view;
    const struct mail_index_record *rec;
    unsigned char *data;
    size_t size, i;
    uint32_t *seq;
    int j;

    if (buf == NULL)
        return;

    /* @UNSAFE */
    data = buffer_get_modifyable_data(buf, &size);
    for (i = 0; i < size; i += record_size) {
        seq = (uint32_t *)&data[i];

        for (j = 0; j <= range; j++, seq++) {
            if (*seq >= t->first_new_seq) {
                rec = mail_index_transaction_lookup(t, *seq);
                *seq = rec->uid;
            } else {
                i_assert(*seq <= view->map->records_count);
                *seq = MAIL_INDEX_MAP_IDX(view->map,
                              *seq - 1)->uid;
            }
            i_assert(*seq != 0);
        }
    }
}

static int
mail_index_transaction_convert_to_uids(struct mail_index_transaction *t)
{
    struct mail_index *index = t->view->index;
        const struct mail_index_ext *extensions;
    buffer_t **updates;
    size_t i, size;

    if (mail_index_view_lock(t->view) < 0)
        return -1;

    if (t->ext_rec_updates != NULL) {
        extensions = buffer_get_data(index->extensions, NULL);
        updates = buffer_get_modifyable_data(t->ext_rec_updates, &size);
        size /= sizeof(*updates);

        for (i = 0; i < size; i++) {
            if (updates[i] == NULL)
                continue;

            mail_index_buffer_convert_to_uids(t, updates[i],
                sizeof(uint32_t) + extensions[i].record_size,
                FALSE);
        }
    }

    if (t->keyword_updates != NULL) {
        struct mail_keyword_transaction **kt;

        kt = buffer_get_modifyable_data(t->keyword_updates, &size);
        size /= sizeof(*kt);

        for (i = 0; i < size; i++) {
            if (kt[i]->messages == NULL)
                continue;

            mail_index_buffer_convert_to_uids(t, kt[i]->messages,
                sizeof(uint32_t) * 2, TRUE);
        }
    }

    mail_index_buffer_convert_to_uids(t, t->expunges,
        sizeof(struct mail_transaction_expunge), TRUE);
    mail_index_buffer_convert_to_uids(t, t->updates,
        sizeof(struct mail_transaction_flag_update), TRUE);
    return 0;
}

int mail_index_transaction_commit(struct mail_index_transaction *t,
                  uint32_t *log_file_seq_r,
                  uoff_t *log_file_offset_r)
{
    int ret;

    if (mail_index_view_is_inconsistent(t->view)) {
        mail_index_transaction_rollback(t);
        return -1;
    }

    if (t->cache_trans_ctx != NULL) {
        mail_cache_transaction_commit(t->cache_trans_ctx);
                t->cache_trans_ctx = NULL;
    }

    if (mail_index_transaction_convert_to_uids(t) < 0)
        ret = -1;
    else {
        ret = mail_transaction_log_append(t, log_file_seq_r,
                          log_file_offset_r);
    }

    mail_index_transaction_unref(t);
    return ret;
}

void mail_index_transaction_rollback(struct mail_index_transaction *t)
{
    if (t->cache_trans_ctx != NULL) {
        mail_cache_transaction_rollback(t->cache_trans_ctx);
                t->cache_trans_ctx = NULL;
    }
        mail_index_transaction_unref(t);
}

struct mail_index_record *
mail_index_transaction_lookup(struct mail_index_transaction *t, uint32_t seq)
{
    size_t pos;

    i_assert(seq >= t->first_new_seq && seq <= t->last_new_seq);

    pos = (seq - t->first_new_seq) * sizeof(struct mail_index_record);
    return buffer_get_space_unsafe(t->appends, pos,
                       sizeof(struct mail_index_record));
}

void mail_index_append(struct mail_index_transaction *t, uint32_t uid,
               uint32_t *seq_r)
{
        struct mail_index_record *rec;

    i_assert(!t->no_appends);

    t->log_updates = TRUE;

    if (t->appends == NULL)
        t->appends = buffer_create_dynamic(default_pool, 4096);

    /* sequence number is visible only inside given view,
       so let it generate it */
    if (t->last_new_seq != 0)
        *seq_r = ++t->last_new_seq;
    else
        *seq_r = t->last_new_seq = t->first_new_seq;

    rec = buffer_append_space_unsafe(t->appends, sizeof(*rec));
    memset(rec, 0, sizeof(*rec));
    rec->uid = uid;
}

void mail_index_append_assign_uids(struct mail_index_transaction *t,
                   uint32_t first_uid, uint32_t *next_uid_r)
{
        struct mail_index_record *rec, *end;
    size_t size;

    if (t->appends == NULL)
        return;

    rec = buffer_get_modifyable_data(t->appends, &size);
    end = PTR_OFFSET(rec, size);

    /* find the first mail with uid = 0 */
    for (; rec != end; rec++) {
        if (rec->uid == 0)
            break;
    }

    for (; rec != end; rec++) {
        i_assert(rec->uid == 0);
        rec->uid = first_uid++;
    }

    *next_uid_r = first_uid;
}

struct seq_range {
    uint32_t seq1, seq2;
};

static void mail_index_update_seq_range_buffer(buffer_t *buffer, uint32_t seq)
{
        struct seq_range *data, value;
    unsigned int idx, left_idx, right_idx;
    size_t size;

    value.seq1 = value.seq2 = seq;

    data = buffer_get_modifyable_data(buffer, &size);
    size /= sizeof(*data);
    i_assert(size > 0);

    /* quick checks */
    if (data[size-1].seq2 == seq-1) {
        /* grow last range */
        data[size-1].seq2 = seq;
        return;
    }
    if (data[size-1].seq2 < seq) {
        buffer_append(buffer, &value, sizeof(value));
        return;
    }
    if (data[0].seq1 == seq+1) {
        /* grow down first range */
        data[0].seq1 = seq;
        return;
    }
    if (data[0].seq1 > seq) {
        buffer_insert(buffer, 0, &value, sizeof(value));
        return;
    }

    /* somewhere in the middle, array is sorted so find it with
       binary search */
    idx = 0; left_idx = 0; right_idx = size;
    while (left_idx < right_idx) {
        idx = (left_idx + right_idx) / 2;

        if (data[idx].seq1 <= seq) {
            if (data[idx].seq2 >= seq) {
                /* it's already expunged */
                return;
            }
            left_idx = idx+1;
        } else {
            right_idx = idx;
        }
    }

    if (data[idx].seq2 < seq)
        idx++;

        /* idx == size couldn't happen because we already handle it above */
    i_assert(idx < size && data[idx].seq1 >= seq);
    i_assert(data[idx].seq1 > seq || data[idx].seq2 < seq);

    if (data[idx].seq1 == seq+1) {
        data[idx].seq1 = seq;
        if (idx > 0 && data[idx-1].seq2 == seq-1) {
            /* merge */
            data[idx-1].seq2 = data[idx].seq2;
            buffer_delete(buffer, idx * sizeof(*data),
                      sizeof(*data));
        }
    } else if (data[idx].seq2 == seq-1) {
        i_assert(idx+1 < size); /* already handled above */
        data[idx].seq2 = seq;
        if (data[idx+1].seq1 == seq+1) {
            /* merge */
            data[idx+1].seq1 = data[idx].seq1;
            buffer_delete(buffer, idx * sizeof(*data),
                      sizeof(*data));
        }
    } else {
        buffer_insert(buffer, idx * sizeof(*data),
                              &value, sizeof(value));
    }
}

void mail_index_expunge(struct mail_index_transaction *t, uint32_t seq)
{
    i_assert(seq > 0 && seq <= mail_index_view_get_messages_count(t->view));

    t->log_updates = TRUE;

    /* expunges is a sorted array of {seq1, seq2, ..}, .. */
    if (t->expunges == NULL) {
        t->expunges = buffer_create_dynamic(default_pool, 1024);
        buffer_append(t->expunges, &seq, sizeof(seq));
        buffer_append(t->expunges, &seq, sizeof(seq));
        return;
    }

    mail_index_update_seq_range_buffer(t->expunges, seq);
}

static void
mail_index_insert_flag_update(struct mail_index_transaction *t,
                  struct mail_transaction_flag_update u,
                  uint32_t left_idx, uint32_t right_idx)
{
    struct mail_transaction_flag_update *updates, tmp_update;
    size_t size;
    uint32_t idx, move;

    updates = buffer_get_modifyable_data(t->updates, &size);
    size /= sizeof(*updates);

    i_assert(left_idx <= right_idx && right_idx <= size);

    /* find the first update with either overlapping range,
       or the update which will come after our insert */
    idx = 0;
    while (left_idx < right_idx) {
        idx = (left_idx + right_idx) / 2;

        if (updates[idx].uid1 < u.uid1)
            left_idx = idx+1;
        else if (updates[idx].uid1 > u.uid1)
            right_idx = idx;
        else
            break;
    }
    if (idx < size && updates[idx].uid2 < u.uid1)
        idx++;

    /* overlapping ranges, split/merge them */
    i_assert(idx == 0 || updates[idx-1].uid2 < u.uid1);

    for (; idx < size && u.uid2 >= updates[idx].uid1; idx++) {
        if (u.uid1 != updates[idx].uid1 &&
            (updates[idx].add_flags != u.add_flags ||
             updates[idx].remove_flags != u.remove_flags)) {
            if (u.uid1 < updates[idx].uid1) {
                /* insert new update */
                tmp_update = u;
                tmp_update.uid2 = updates[idx].uid1 - 1;
                move = 0;
            } else {
                /* split existing update from beginning */
                tmp_update = updates[idx];
                tmp_update.uid2 = u.uid1 - 1;
                updates[idx].uid1 = u.uid1;
                move = 1;
            }

            i_assert(tmp_update.uid1 <= tmp_update.uid2);
            i_assert(updates[idx].uid1 <= updates[idx].uid2);

            buffer_insert(t->updates, idx * sizeof(tmp_update),
                      &tmp_update, sizeof(tmp_update));
            updates = buffer_get_modifyable_data(t->updates, NULL);
            size++; idx += move;
        } else if (u.uid1 < updates[idx].uid1) {
            updates[idx].uid1 = u.uid1;
        }

        if (u.uid2 < updates[idx].uid2 &&
            (updates[idx].add_flags != u.add_flags ||
             updates[idx].remove_flags != u.remove_flags)) {
            /* split existing update from end */
            tmp_update = updates[idx];
            tmp_update.uid2 = u.uid2;
            updates[idx].uid1 = u.uid2 + 1;

            i_assert(tmp_update.uid1 <= tmp_update.uid2);
            i_assert(updates[idx].uid1 <= updates[idx].uid2);

            buffer_insert(t->updates, idx * sizeof(tmp_update),
                      &tmp_update, sizeof(tmp_update));
            updates = buffer_get_modifyable_data(t->updates, NULL);
            size++;
        }

        updates[idx].add_flags =
            (updates[idx].add_flags | u.add_flags) &
            ~u.remove_flags;
        updates[idx].remove_flags =
            (updates[idx].remove_flags | u.remove_flags) &
            ~u.add_flags;

        u.uid1 = updates[idx].uid2 + 1;
        if (u.uid1 > u.uid2) {
            /* break here before idx++ so last_update_idx is set
               correctly */
            break;
        }
    }
    i_assert(idx <= size);

    if (u.uid1 <= u.uid2) {
        i_assert(idx == 0 || updates[idx-1].uid2 < u.uid1);
        i_assert(idx == size || updates[idx].uid1 > u.uid2);
        buffer_insert(t->updates, idx * sizeof(u), &u, sizeof(u));
    }
    t->last_update_idx = idx;
}

static void mail_index_record_modify_flags(struct mail_index_record *rec,
                       enum modify_type modify_type,
                       enum mail_flags flags)
{
    switch (modify_type) {
    case MODIFY_REPLACE:
        rec->flags = flags;
        break;
    case MODIFY_ADD:
        rec->flags |= flags;
        break;
    case MODIFY_REMOVE:
        rec->flags &= ~flags;
        break;
    }
}

void mail_index_update_flags_range(struct mail_index_transaction *t,
                   uint32_t seq1, uint32_t seq2,
                   enum modify_type modify_type,
                   enum mail_flags flags)
{
    struct mail_index_record *rec;
    struct mail_transaction_flag_update u, *last_update;
    size_t size;

    t->log_updates = TRUE;

    if (seq2 >= t->first_new_seq) {
        /* updates for appended messages, modify them directly */
        uint32_t seq;

        for (seq = I_MAX(t->first_new_seq, seq1); seq <= seq2; seq++) {
            rec = mail_index_transaction_lookup(t, seq);
            mail_index_record_modify_flags(rec, modify_type, flags);
        }
        if (seq1 >= t->first_new_seq)
            return;

        /* range contains also existing messages. update them next. */
        seq2 = t->first_new_seq - 1;
    }

    i_assert(seq1 <= seq2 && seq1 > 0);
    i_assert(seq2 <= mail_index_view_get_messages_count(t->view));

    memset(&u, 0, sizeof(u));
    u.uid1 = seq1;
    u.uid2 = seq2;

    switch (modify_type) {
    case MODIFY_REPLACE:
        u.add_flags = flags;
        u.remove_flags = ~flags & MAIL_INDEX_FLAGS_MASK;
        break;
    case MODIFY_ADD:
        u.add_flags = flags;
        break;
    case MODIFY_REMOVE:
        u.remove_flags = flags;
        break;
    }

    if (t->updates == NULL) {
        t->updates = buffer_create_dynamic(default_pool, 4096);
        buffer_append(t->updates, &u, sizeof(u));
        return;
    }

    last_update = buffer_get_modifyable_data(t->updates, &size);
    size /= sizeof(*last_update);

    if (t->last_update_idx < size) {
        /* fast path - hopefully we're updating the next message,
           or a message that is to be appended as last update */
        last_update += t->last_update_idx;
        if (seq1 - 1 == last_update->uid2) {
            if (u.add_flags == last_update->add_flags &&
                u.remove_flags == last_update->remove_flags &&
                (t->last_update_idx + 1 == size ||
                 last_update[1].uid1 > seq2)) {
                /* we can just update the UID range */
                last_update->uid2 = seq2;
                return;
            }
        } else if (seq1 > last_update->uid2) {
            /* hopefully we can just append it */
            t->last_update_idx++;
            last_update++;
        }
    }

    if (t->last_update_idx == size) {
        buffer_append(t->updates, &u, sizeof(u));
        return;
    }

    /* slow path */
    if (seq1 > last_update->uid2) {
        /* added after this */
        mail_index_insert_flag_update(t, u, t->last_update_idx + 1,
                          size);
    } else {
        /* added before this or on top of this */
        mail_index_insert_flag_update(t, u, 0, t->last_update_idx);
    }
}

void mail_index_update_flags(struct mail_index_transaction *t, uint32_t seq,
                 enum modify_type modify_type,
                 enum mail_flags flags)
{
    mail_index_update_flags_range(t, seq, seq, modify_type, flags);
}

int mail_index_seq_buffer_lookup(buffer_t *buffer, uint32_t seq,
                 size_t record_size, size_t *pos_r)
{
    unsigned int idx, left_idx, right_idx;
    void *data;
    uint32_t full_record_size, *seq_p;
    size_t size;

    full_record_size = record_size + sizeof(seq);

    data = buffer_get_modifyable_data(buffer, &size);

    /* we're probably appending it, check */
    if (size == 0)
        idx = 0;
    else if (*((uint32_t *)PTR_OFFSET(data, size-full_record_size)) < seq)
        idx = size / full_record_size;
    else {
        idx = 0; left_idx = 0; right_idx = size / full_record_size;
        while (left_idx < right_idx) {
            idx = (left_idx + right_idx) / 2;

            seq_p = PTR_OFFSET(data, idx * full_record_size);
            if (*seq_p < seq)
                left_idx = idx+1;
            else if (*seq_p > seq)
                right_idx = idx;
            else {
                *pos_r = idx * full_record_size;
                return TRUE;
            }
        }
    }

    *pos_r = idx * full_record_size;
    return FALSE;
}

static int mail_index_update_seq_buffer(buffer_t **buffer, uint32_t seq,
                    const void *record, size_t record_size,
                    void *old_record)
{
    void *p;
    size_t pos;

    if (*buffer == NULL) {
        *buffer = buffer_create_dynamic(default_pool, 1024);
        buffer_append(*buffer, &seq, sizeof(seq));
        buffer_append(*buffer, record, record_size);
        return FALSE;
    }

    if (mail_index_seq_buffer_lookup(*buffer, seq, record_size, &pos)) {
        /* already there, update */
        p = buffer_get_space_unsafe(*buffer, pos + sizeof(seq),
                        record_size);
        if (old_record != NULL)
            memcpy(old_record, p, record_size);
        memcpy(p, record, record_size);
        return TRUE;
    } else {
        /* insert */
        buffer_copy(*buffer, pos + sizeof(seq) + record_size,
                *buffer, pos, (size_t)-1);
        buffer_write(*buffer, pos, &seq, sizeof(seq));
        buffer_write(*buffer, pos + sizeof(seq), record, record_size);
        return FALSE;
    }
}

void mail_index_update_header(struct mail_index_transaction *t,
                  size_t offset, const void *data, size_t size)
{
    i_assert(offset < sizeof(t->hdr_change));
    i_assert(size <= sizeof(t->hdr_change) - offset);

    t->hdr_changed = TRUE;
    t->log_updates = TRUE;

    memcpy(t->hdr_change + offset, data, size);
    for (; size > 0; size--)
        t->hdr_mask[offset++] = 1;
}

void mail_index_ext_resize(struct mail_index_transaction *t, uint32_t ext_id,
               uint32_t hdr_size, uint16_t record_size,
               uint16_t record_align)
{
    struct mail_transaction_ext_intro intro;
    const struct mail_index_ext *ext;

    memset(&intro, 0, sizeof(intro));

    if (!mail_index_map_get_ext_idx(t->view->map, ext_id, &intro.ext_id)) {
        intro.ext_id = (uint32_t)-1;
        ext = t->view->index->extensions->data;
        ext += ext_id;
    } else {
        ext = t->view->map->extensions->data;
        ext += ext_id;
    }

    /* allow only header size changes if something was already written */
    i_assert(t->ext_rec_updates == NULL ||
         (ext->record_size == record_size &&
          ext->record_align == record_align));

    t->log_updates = TRUE;

    if (t->ext_resizes == NULL)
        t->ext_resizes = buffer_create_dynamic(default_pool, 128);

    intro.hdr_size = hdr_size;
    intro.record_size = record_size;
    intro.record_align = record_align;
    intro.name_size = 1;
    buffer_write(t->ext_resizes, ext_id * sizeof(intro),
             &intro, sizeof(intro));
}

void mail_index_ext_reset(struct mail_index_transaction *t, uint32_t ext_id,
              uint32_t reset_id)
{
    size_t pos;

    i_assert(reset_id != 0);

    t->log_updates = TRUE;

    if (t->ext_rec_updates != NULL &&
        ext_id < t->ext_rec_updates->used / sizeof(buffer_t *)) {
        buffer_t *const *buf = t->ext_rec_updates->data;
        buf += ext_id;

        if (*buf != NULL)
            buffer_set_used_size(*buf, 0);
    }

    pos = ext_id * sizeof(uint32_t);
    if (t->ext_resets == NULL) {
        t->ext_resets = buffer_create_dynamic(default_pool,
                              pos + sizeof(uint32_t));
    }
    buffer_write(t->ext_resets, pos, &reset_id, sizeof(reset_id));
}

void mail_index_update_header_ext(struct mail_index_transaction *t,
                  uint32_t ext_id, size_t offset,
                  const void *data, size_t size)
{
    // FIXME
}

void mail_index_update_ext(struct mail_index_transaction *t, uint32_t seq,
               uint32_t ext_id, const void *data, void *old_data_r)
{
    struct mail_index *index = t->view->index;
        const struct mail_index_ext *ext;
    const struct mail_transaction_ext_intro *intro;
    buffer_t **buf;
    uint16_t record_size;
    size_t size;

    i_assert(seq > 0 &&
         (seq <= mail_index_view_get_messages_count(t->view) ||
          seq <= t->last_new_seq));
    i_assert(ext_id < index->extensions->used / sizeof(*ext));

    t->log_updates = TRUE;

    if (t->ext_resizes == NULL) {
        intro = NULL;
        size = 0;
    } else {
        intro = buffer_get_data(t->ext_resizes, &size);
    }
    if (ext_id < size / sizeof(*intro) && intro[ext_id].name_size != 0) {
        /* resized record */
        record_size = intro[ext_id].record_size;
    } else {
        ext = index->extensions->data;
        record_size = ext[ext_id].record_size;
    }

    if (t->ext_rec_updates == NULL)
        t->ext_rec_updates = buffer_create_dynamic(default_pool, 128);
    buf = buffer_get_space_unsafe(t->ext_rec_updates,
                      ext_id * sizeof(buffer_t *),
                      sizeof(buffer_t *));

    /* @UNSAFE */
    if (!mail_index_update_seq_buffer(buf, seq, data, record_size,
                      old_data_r)) {
        if (old_data_r != NULL)
            memset(old_data_r, 0, record_size);
    }
}

static struct mail_keyword_transaction *
mail_keyword_transaction_new(struct mail_index_transaction *t,
                 struct mail_keywords *keywords)
{
    struct mail_keyword_transaction *kt;

    if (t->keyword_updates == NULL)
                t->keyword_updates = buffer_create_dynamic(default_pool, 512);

    kt = i_new(struct mail_keyword_transaction, 1);
    kt->transaction = t;
    kt->keywords = keywords;

    kt->next = keywords->kt;
    keywords->kt = kt;

    buffer_append(t->keyword_updates, &kt, sizeof(kt));
    return kt;
}

static struct mail_keywords *
mail_index_keywords_build(struct mail_index *index,
              const char *const keywords[], unsigned int count)
{
    struct mail_keywords k;
    const char **missing_keywords, *keyword;
    buffer_t *keyword_buf;
    unsigned int i, j, bitmask_offset, missing_count = 0;
    size_t size;
    uint8_t *b;

    if (count == 0)
        return i_new(struct mail_keywords, 1);

    /* @UNSAFE */
    t_push();

    missing_keywords = t_new(const char *, count + 1);
    memset(&k, 0, sizeof(k));

    /* keywords are sorted in index. look up the existing ones and add
       new ones. build a bitmap pointing to them. keywords are never
       removed from index's keyword list. */
    bitmask_offset = sizeof(k) - sizeof(k.bitmask);
    keyword_buf = buffer_create_dynamic(default_pool, bitmask_offset +
                        (count + 7) / 8 + 8);
    for (i = 0; i < count; i++) {
        for (j = 0; index->keywords[j] != NULL; j++) {
            if (strcasecmp(keywords[i], index->keywords[j]) == 0)
                break;
        }

        if (index->keywords[j] != NULL) {
            if (keyword_buf->used == 0) {
                /* first one */
                k.start = j;
            } else if (j < k.start) {
                buffer_copy(keyword_buf,
                        bitmask_offset + k.start - j,
                        keyword_buf, bitmask_offset,
                        (size_t)-1);
                k.start = j;
            }
            b = buffer_get_space_unsafe(keyword_buf,
                            bitmask_offset +
                            (j - k.start) / 8, 1);
            *b |= 1 << ((j - k.start) % 8);
            k.end = j;
            k.count++;
        } else {
            /* arrays are sorted, can't match anymore */
            missing_keywords[missing_count++] = keywords[i];
        }
    }

    if (missing_count > 0) {
        /* add missing keywords. first drop the trailing NULL. */
        size = index->keywords_buf->used - sizeof(const char *);
        buffer_set_used_size(index->keywords_buf, size);

        j = size / sizeof(const char *);
        for (; *missing_keywords != NULL; missing_keywords++, j++) {
            keyword = p_strdup(index->keywords_pool,
                       *missing_keywords);
            buffer_append(index->keywords_buf,
                      &keyword, sizeof(keyword));

            b = buffer_get_space_unsafe(keyword_buf,
                            bitmask_offset +
                            (j - k.start) / 8, 1);
            *b |= 1 << ((j - k.start) % 8);
            k.end = j;
            k.count++;
        }

        buffer_append_zero(index->keywords_buf, sizeof(const char *));
        index->keywords = index->keywords_buf->data;
    }
    buffer_write(keyword_buf, 0, &k, bitmask_offset);

    t_pop();
    return buffer_free_without_data(keyword_buf);
}

struct mail_keywords *
mail_index_keywords_create(struct mail_index_transaction *t,
               const char *const keywords[])
{
    struct mail_keywords *k;
    const char *const null_keywords[] = { NULL };

    if (keywords == NULL)
        keywords = null_keywords;

    k = mail_index_keywords_build(t->view->index, keywords,
                      strarray_length(keywords));
    (void)mail_keyword_transaction_new(t, k);
    return k;
}

void mail_index_update_keywords(struct mail_index_transaction *t, uint32_t seq,
                enum modify_type modify_type,
                struct mail_keywords *keywords)
{
    struct mail_keyword_transaction *kt;

    i_assert(seq > 0 &&
         (seq <= mail_index_view_get_messages_count(t->view) ||
          seq <= t->last_new_seq));
    i_assert(keywords->count > 0 || modify_type == MODIFY_REPLACE);
    i_assert(keywords->kt->transaction->view->index == t->view->index);

    for (kt = keywords->kt; kt != NULL; kt = kt->next) {
        if (kt->transaction == t &&
            (kt->modify_type == modify_type || kt->messages == NULL))
            break;
    }

    if (kt == NULL)
        kt = mail_keyword_transaction_new(t, keywords);

    if (kt->messages == NULL) {
        kt->messages = buffer_create_dynamic(default_pool, 32);
        kt->modify_type = modify_type;
        buffer_append(kt->messages, &seq, sizeof(seq));
        buffer_append(kt->messages, &seq, sizeof(seq));
    } else {
        mail_index_update_seq_range_buffer(kt->messages, seq);
    }
    t->log_updates = TRUE;
}