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

	mail-index-sync.c revision 0add8c99ca65e56dbf613595fc37c41aafff3f7f
/* Copyright (C) 2003-2004 Timo Sirainen */

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

#include <stdlib.h>

static void mail_index_sync_sort_flags(struct mail_index_sync_ctx *ctx)
{
    const struct mail_transaction_flag_update *src, *src_end;
    const struct mail_transaction_flag_update *dest;
    struct mail_transaction_flag_update new_update;
    struct mail_transaction_expunge_traverse_ctx *exp_ctx;
    uint32_t last;
    size_t i, dest_count;

    src = ctx->data;
    src_end = PTR_OFFSET(src, ctx->hdr->size);

    dest = buffer_get_data(ctx->updates_buf, &dest_count);
    dest_count /= sizeof(*dest);

    exp_ctx = mail_transaction_expunge_traverse_init(ctx->expunges_buf);

    for (i = 0; src != src_end; src++) {
        new_update = *src;

        /* find seq1 */
        new_update.seq1 +=
            mail_transaction_expunge_traverse_to(exp_ctx,
                                 src->seq1);

        /* find seq2 */
        new_update.seq2 +=
            mail_transaction_expunge_traverse_to(exp_ctx,
                                 src->seq2);

        /* insert it into buffer, split it in multiple parts if needed
           to make sure the ordering stays the same */
        for (; i < dest_count; i++) {
            if (dest[i].seq1 <= new_update.seq1)
                continue;

            if (dest[i].seq1 > new_update.seq2)
                break;

            /* partial */
            last = new_update.seq2;
            new_update.seq2 = dest[i].seq1-1;

            buffer_insert(ctx->updates_buf, i * sizeof(new_update),
                      &new_update, sizeof(new_update));
            dest = buffer_get_data(ctx->updates_buf, NULL);
            dest_count++;

            new_update.seq1 = new_update.seq2+1;
            new_update.seq2 = last;
        }

        buffer_insert(ctx->updates_buf, i * sizeof(new_update),
                  &new_update, sizeof(new_update));
        dest = buffer_get_data(ctx->updates_buf, NULL);
        dest_count++;
    }
    mail_transaction_expunge_traverse_deinit(exp_ctx);
}

static void mail_index_sync_sort_transaction(struct mail_index_sync_ctx *ctx)
{
    switch (ctx->hdr->type & MAIL_TRANSACTION_TYPE_MASK) {
    case MAIL_TRANSACTION_EXPUNGE:
        if (buffer_get_used_size(ctx->expunges_buf) == 0) {
            buffer_append(ctx->expunges_buf, ctx->data,
                      ctx->hdr->size);
        } else {
            mail_transaction_log_sort_expunges(ctx->expunges_buf,
                               ctx->data,
                               ctx->hdr->size);
        }
        break;
    case MAIL_TRANSACTION_FLAG_UPDATE:
        if (buffer_get_used_size(ctx->expunges_buf) == 0 &&
            buffer_get_used_size(ctx->updates_buf) == 0) {
            buffer_append(ctx->updates_buf, ctx->data,
                      ctx->hdr->size);
        } else {
            mail_index_sync_sort_flags(ctx);
        }
        break;
    case MAIL_TRANSACTION_APPEND:
        buffer_append(ctx->appends_buf, ctx->data, ctx->hdr->size);
                ctx->sync_appends = TRUE;
        break;
    }
}

static int mail_index_sync_read_and_sort(struct mail_index_sync_ctx *ctx,
                     int external)
{
        enum mail_transaction_type flag;
    size_t size;
    int ret;

    flag = external ? MAIL_TRANSACTION_EXTERNAL : 0;
    while ((ret = mail_transaction_log_view_next(ctx->view->log_view,
                             &ctx->hdr,
                             &ctx->data, NULL)) > 0) {
        if ((ctx->hdr->type & MAIL_TRANSACTION_EXTERNAL) == flag)
            mail_index_sync_sort_transaction(ctx);
    }

    ctx->expunges = buffer_get_data(ctx->expunges_buf, &size);
    ctx->expunges_count = size / sizeof(*ctx->expunges);
    ctx->updates = buffer_get_data(ctx->updates_buf, &size);
    ctx->updates_count = size / sizeof(*ctx->updates);

    return ret;
}

static int mail_index_need_lock(struct mail_index *index,
                uint32_t log_file_seq, uoff_t log_file_offset)
{
    if (index->hdr->log_file_seq > log_file_seq ||
         (index->hdr->log_file_seq == log_file_seq &&
          index->hdr->log_file_offset >= log_file_offset)) {
        /* already synced */
        return 0;
    }

    return 1;
}

int mail_index_sync_begin(struct mail_index *index,
                          struct mail_index_sync_ctx **ctx_r,
              struct mail_index_view **view_r,
              uint32_t log_file_seq, uoff_t log_file_offset)
{
    struct mail_index_sync_ctx *ctx;
    uint32_t seq;
    uoff_t offset;
    unsigned int lock_id;

    if (mail_transaction_log_sync_lock(index->log, &seq, &offset) < 0)
        return -1;

    if (mail_index_lock_shared(index, TRUE, &lock_id) < 0) {
        mail_transaction_log_sync_unlock(index->log);
        return -1;
    }

    if (mail_index_map(index, FALSE) <= 0) {
        mail_transaction_log_sync_unlock(index->log);
        mail_index_unlock(index, lock_id);
        return -1;
    }

    if (!mail_index_need_lock(index, log_file_seq, log_file_offset)) {
        mail_index_unlock(index, lock_id);
        mail_transaction_log_sync_unlock(index->log);
        return 0;
    }

    ctx = i_new(struct mail_index_sync_ctx, 1);
    ctx->index = index;
    ctx->lock_id = lock_id;

    ctx->view = mail_index_view_open(index);
    ctx->view->external = TRUE;

    if (mail_transaction_log_view_set(ctx->view->log_view,
                      index->hdr->log_file_seq,
                      index->hdr->log_file_offset,
                      seq, offset,
                      MAIL_TRANSACTION_TYPE_MASK) < 0) {
                mail_index_sync_end(ctx);
        return -1;
    }

    /* we need to have all the transactions sorted to optimize
       caller's mailbox access patterns */
    ctx->expunges_buf = buffer_create_dynamic(default_pool,
                          1024, (size_t)-1);
    ctx->updates_buf = buffer_create_dynamic(default_pool,
                         1024, (size_t)-1);
    ctx->appends_buf = buffer_create_dynamic(default_pool,
                         1024, (size_t)-1);
    if (mail_index_sync_read_and_sort(ctx, FALSE) < 0) {
                mail_index_sync_end(ctx);
        return -1;
    }

    *ctx_r = ctx;
    *view_r = ctx->view;
    return 1;
}

static void
mail_index_sync_get_expunge(struct mail_index_sync_rec *rec,
                const struct mail_transaction_expunge *exp)
{
    rec->type = MAIL_INDEX_SYNC_TYPE_EXPUNGE;
    rec->seq1 = exp->seq1;
    rec->seq2 = exp->seq2;
}

static void
mail_index_sync_get_update(struct mail_index_sync_rec *rec,
               const struct mail_transaction_flag_update *update)
{
    rec->type = MAIL_INDEX_SYNC_TYPE_FLAGS;
    rec->seq1 = update->seq1;
    rec->seq2 = update->seq2;

    rec->add_flags = update->add_flags;
    memcpy(rec->add_custom_flags, update->add_custom_flags,
           sizeof(rec->add_custom_flags));
    rec->remove_flags = update->remove_flags;
    memcpy(rec->remove_custom_flags, update->remove_custom_flags,
           sizeof(rec->remove_custom_flags));
}

static int mail_index_sync_rec_check(struct mail_index_view *view,
                     struct mail_index_sync_rec *rec)
{
    uint32_t message_count;

    switch (rec->type) {
    case MAIL_INDEX_SYNC_TYPE_EXPUNGE:
    case MAIL_INDEX_SYNC_TYPE_FLAGS:
        if (rec->seq1 > rec->seq2 || rec->seq1 == 0) {
            mail_transaction_log_view_set_corrupted(view->log_view,
                "Broken sequence: %u..%u",
                rec->seq1, rec->seq2);
            return FALSE;
        }

        message_count = mail_index_view_get_message_count(view);
        if (rec->seq2 > message_count) {
            mail_transaction_log_view_set_corrupted(view->log_view,
                "Sequence out of range: %u > %u",
                rec->seq2, message_count);
            return FALSE;
        }
        break;
    case MAIL_INDEX_SYNC_TYPE_APPEND:
        break;
    }
    return TRUE;
}

int mail_index_sync_get_rec(struct mail_index_view *view,
                struct mail_index_sync_rec *rec,
                const struct mail_transaction_header *hdr,
                const void *data, size_t *data_offset)
{
    switch (hdr->type & MAIL_TRANSACTION_TYPE_MASK) {
    case MAIL_TRANSACTION_APPEND: {
        rec->type = MAIL_INDEX_SYNC_TYPE_APPEND;
        rec->seq1 = view->index->map->records_count + 1;
        rec->seq2 = rec->seq1 + hdr->size /
            sizeof(struct mail_index_record) - 1;
        rec->appends = NULL;

        *data_offset += hdr->size;
        break;
    }
    case MAIL_TRANSACTION_EXPUNGE: {
        const struct mail_transaction_expunge *exp =
            CONST_PTR_OFFSET(data, *data_offset);

        *data_offset += sizeof(*exp);
                mail_index_sync_get_expunge(rec, exp);
        break;
    }
    case MAIL_TRANSACTION_FLAG_UPDATE: {
        const struct mail_transaction_flag_update *update =
            CONST_PTR_OFFSET(data, *data_offset);

        *data_offset += sizeof(*update);
                mail_index_sync_get_update(rec, update);
        break;
    }
    default:
        i_unreached();
    }

    return mail_index_sync_rec_check(view, rec);
}

int mail_index_sync_next(struct mail_index_sync_ctx *ctx,
             struct mail_index_sync_rec *sync_rec)
{
    const struct mail_transaction_expunge *next_exp;
    const struct mail_transaction_flag_update *next_update;

    next_exp = ctx->expunge_idx == ctx->expunges_count ? NULL :
        &ctx->expunges[ctx->expunge_idx];
    next_update = ctx->update_idx == ctx->updates_count ? NULL :
        &ctx->updates[ctx->update_idx];

    /* the ugliness here is to avoid returning overlapping expunge
       and update areas. For example:

       updates[] = A { 1, 7 }, B { 1, 3 }
       expunges[] = { 5, 6 }

       will make us return

       update A: 1, 4
       update B: 1, 3
       expunge : 5, 6
       update A: 7, 7
    */
    while (next_update != NULL &&
           (next_exp == NULL || next_update->seq1 < next_exp->seq1)) {
        if (next_update->seq2 >= ctx->next_seq) {
            mail_index_sync_get_update(sync_rec, next_update);
            if (next_exp != NULL &&
                next_exp->seq1 <= next_update->seq2) {
                /* it's overlapping.. */
                sync_rec->seq2 = next_exp->seq1-1;
            }

            if (sync_rec->seq1 < ctx->next_seq)
                sync_rec->seq1 = ctx->next_seq;

            i_assert(sync_rec->seq1 <= sync_rec->seq2);
            ctx->update_idx++;
            return mail_index_sync_rec_check(ctx->view, sync_rec);
        }

        if (++ctx->update_idx == ctx->updates_count)
            break;
        next_update++;
    }

    if (next_exp != NULL) {
        /* a few sanity checks here, we really don't ever want to
           accidentally expunge a message. If sequence and UID matches,
           it's quite unlikely this expunge was caused by some bug. */
        uint32_t uid1, uid2;

        if (next_exp->seq1 > ctx->view->map->records_count ||
            next_exp->seq2 > ctx->view->map->records_count) {
            mail_transaction_log_view_set_corrupted(
                ctx->view->log_view, "Expunge range %u..%u "
                "larger than message count %u",
                next_exp->seq1, next_exp->seq2,
                ctx->view->map->records_count);
            return -1;
        }

        if (mail_index_lookup_uid(ctx->view, next_exp->seq1, &uid1) < 0)
            return -1;
        if (mail_index_lookup_uid(ctx->view, next_exp->seq2, &uid2) < 0)
            return -1;
        if (next_exp->uid1 != uid1 || next_exp->uid2 != uid2) {
            mail_transaction_log_view_set_corrupted(
                ctx->view->log_view, "Expunge range %u..%u: "
                "UIDs %u..%u doesn't match real UIDs %u..%u",
                next_exp->seq1, next_exp->seq2,
                next_exp->uid1, next_exp->uid2, uid1, uid2);
            return -1;
        }

        mail_index_sync_get_expunge(sync_rec, next_exp);
        ctx->expunge_idx++;

        /* scan updates again from the beginning */
        ctx->update_idx = 0;
        ctx->next_seq = next_exp->seq2;
        return mail_index_sync_rec_check(ctx->view, sync_rec);
    }

    if (ctx->sync_appends) {
        ctx->sync_appends = FALSE;
        sync_rec->type = MAIL_INDEX_SYNC_TYPE_APPEND;
        sync_rec->seq1 = ctx->index->map->records_count+1;
        sync_rec->seq2 = sync_rec->seq1-1 +
            buffer_get_used_size(ctx->appends_buf) /
            sizeof(struct mail_index_record);
        sync_rec->appends = buffer_get_data(ctx->appends_buf, NULL);
        return 1;
    }

    return 0;
}

int mail_index_sync_have_more(struct mail_index_sync_ctx *ctx)
{
    return (ctx->update_idx != ctx->updates_count) ||
        (ctx->expunge_idx != ctx->expunges_count) ||
        ctx->sync_appends;
}

int mail_index_sync_end(struct mail_index_sync_ctx *ctx)
{
    uint32_t seq;
    uoff_t offset;
    int ret = 0;

    if (mail_transaction_log_view_is_corrupted(ctx->view->log_view))
        ret = -1;

    mail_transaction_log_get_head(ctx->index->log, &seq, &offset);

    if (mail_transaction_log_view_set(ctx->view->log_view,
                      ctx->index->hdr->log_file_seq,
                      ctx->index->hdr->log_file_offset,
                      seq, offset,
                      MAIL_TRANSACTION_TYPE_MASK) < 0)
        ret = -1;

    if (ret == 0) {
        mail_index_sync_read_and_sort(ctx, TRUE);
        if (mail_index_sync_update_index(ctx) < 0)
            ret = -1;
    }

    mail_index_unlock(ctx->index, ctx->lock_id);
    mail_transaction_log_sync_unlock(ctx->index->log);

    if (ctx->view != NULL)
        mail_index_view_close(ctx->view);
    if (ctx->expunges_buf != NULL)
        buffer_free(ctx->expunges_buf);
    if (ctx->updates_buf != NULL)
        buffer_free(ctx->updates_buf);
    if (ctx->appends_buf != NULL)
        buffer_free(ctx->appends_buf);
    i_free(ctx);
    return ret;
}

void mail_index_sync_flags_apply(const struct mail_index_sync_rec *sync_rec,
                 uint8_t *flags,
                 custom_flags_mask_t custom_flags)
{
    int i;

    i_assert(sync_rec->type == MAIL_INDEX_SYNC_TYPE_FLAGS);

    *flags = (*flags & ~sync_rec->remove_flags) | sync_rec->add_flags;
    for (i = 0; i < INDEX_CUSTOM_FLAGS_BYTE_COUNT; i++) {
        custom_flags[i] =
            (custom_flags[i] & ~sync_rec->remove_custom_flags[i]) |
            sync_rec->add_custom_flags[i];
    }
}