plugins/expire/expire-plugin.c

	expire-plugin.c revision 783278c012551bc2f25f065a8d3ec1a3cfc0d296
/* Copyright (c) 2006-2008 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "ioloop.h"
#include "array.h"
#include "str.h"
#include "dict.h"
#include "mail-namespace.h"
#include "index-mail.h"
#include "index-storage.h"
#include "expire-env.h"
#include "expire-plugin.h"

#include <stdlib.h>

#define EXPIRE_CONTEXT(obj) \
    MODULE_CONTEXT(obj, expire_storage_module)
#define EXPIRE_MAIL_CONTEXT(obj) \
    MODULE_CONTEXT(obj, expire_mail_module)

struct expire {
    struct dict *db;
    struct expire_env *env;

    void (*next_hook_mail_storage_created)(struct mail_storage *storage);
};

struct expire_mailbox {
    union mailbox_module_context module_ctx;
    time_t expire_secs;
    unsigned int altmove:1;
};

struct expire_transaction_context {
    union mailbox_transaction_module_context module_ctx;

    unsigned int saves:1;
    unsigned int first_expunged:1;
};

const char *expire_plugin_version = PACKAGE_VERSION;

static struct expire expire;
static MODULE_CONTEXT_DEFINE_INIT(expire_storage_module,
                  &mail_storage_module_register);
static MODULE_CONTEXT_DEFINE_INIT(expire_mail_module, &mail_module_register);

static struct mailbox_transaction_context *
expire_mailbox_transaction_begin(struct mailbox *box,
                 enum mailbox_transaction_flags flags)
{
    struct expire_mailbox *xpr_box = EXPIRE_CONTEXT(box);
    struct mailbox_transaction_context *t;
    struct expire_transaction_context *xt;

    t = xpr_box->module_ctx.super.transaction_begin(box, flags);
    xt = i_new(struct expire_transaction_context, 1);

    MODULE_CONTEXT_SET(t, expire_storage_module, xt);
    return t;
}

static void first_nonexpunged_timestamp(struct mailbox_transaction_context *_t,
                    time_t *stamp_r)
{
    struct index_transaction_context *t =
        (struct index_transaction_context *)_t;
    struct mail_index_view *view = t->trans_view;
    const struct mail_index_header *hdr;
    struct mail *mail;
    uint32_t seq;

    mail = mail_alloc(_t, 0, NULL);

    /* find the first non-expunged mail. we're here because the first
       mail was expunged, so don't bother checking it. */
    hdr = mail_index_get_header(view);
    for (seq = 2; seq <= hdr->messages_count; seq++) {
        if (!mail_index_is_expunged(view, seq)) {
            mail_set_seq(mail, seq);
            if (mail_get_save_date(mail, stamp_r) == 0)
                break;
        }
    }
    mail_free(&mail);

    if (seq > hdr->messages_count) {
        /* everything expunged */
        *stamp_r = 0;
    }
}

static int
expire_mailbox_transaction_commit(struct mailbox_transaction_context *t,
                  uint32_t *uid_validity_r,
                  uint32_t *first_saved_uid_r,
                  uint32_t *last_saved_uid_r)
{
    struct expire_mailbox *xpr_box = EXPIRE_CONTEXT(t->box);
    struct expire_transaction_context *xt = EXPIRE_CONTEXT(t);
    struct mailbox *box = t->box;
    time_t new_stamp;
    bool update_dict = FALSE;
    int ret;

    if (xpr_box->altmove) {
        /* only moving mails - don't update the move stamps */
    } else if (xt->first_expunged) {
        /* first mail expunged. dict needs updating. */
        first_nonexpunged_timestamp(t, &new_stamp);
        update_dict = TRUE;
    }

    if (xpr_box->module_ctx.super.
            transaction_commit(t, uid_validity_r,
                   first_saved_uid_r, last_saved_uid_r) < 0) {
        i_free(xt);
        return -1;
    }
    /* transaction is freed now */
    t = NULL;

    if (xt->first_expunged || xt->saves) T_BEGIN {
        const char *key, *value;

        key = t_strconcat(DICT_EXPIRE_PREFIX,
                  box->storage->ns->user->username, "/",
                  box->storage->ns->prefix, box->name, NULL);
        if (!xt->first_expunged && xt->saves) {
            /* saved new mails. dict needs to be updated only if
               this is the first mail in the database */
            ret = dict_lookup(expire.db, pool_datastack_create(),
                      key, &value);
            update_dict = ret == 0 ||
                (ret > 0 && strtoul(value, NULL, 10) == 0);
            /* may not be exactly the first message's save time
               but a few second difference doesn't matter */
            new_stamp = ioloop_time;
        }

        if (update_dict) {
            struct dict_transaction_context *dctx;

            dctx = dict_transaction_begin(expire.db);
            if (new_stamp == 0) {
                /* everything expunged */
                dict_unset(dctx, key);
            } else {
                new_stamp += xpr_box->expire_secs;
                dict_set(dctx, key, dec2str(new_stamp));
            }
            dict_transaction_commit(&dctx);
        }
    } T_END;
    i_free(xt);
    return 0;
}

static void
expire_mailbox_transaction_rollback(struct mailbox_transaction_context *t)
{
    struct expire_mailbox *xpr_box = EXPIRE_CONTEXT(t->box);
    struct expire_transaction_context *xt = EXPIRE_CONTEXT(t);

    xpr_box->module_ctx.super.transaction_rollback(t);
    i_free(xt);
}

static void expire_mail_expunge(struct mail *_mail)
{
    struct mail_private *mail = (struct mail_private *)_mail;
    union mail_module_context *xpr_mail = EXPIRE_MAIL_CONTEXT(mail);
    struct expire_transaction_context *xt =
        EXPIRE_CONTEXT(_mail->transaction);

    if (_mail->seq == 1) {
        /* first mail expunged, database needs to be updated */
        xt->first_expunged = TRUE;
    }
    xpr_mail->super.expunge(_mail);
}

static struct mail *
expire_mail_alloc(struct mailbox_transaction_context *t,
          enum mail_fetch_field wanted_fields,
          struct mailbox_header_lookup_ctx *wanted_headers)
{
    struct expire_mailbox *xpr_box = EXPIRE_CONTEXT(t->box);
    union mail_module_context *xpr_mail;
    struct mail *_mail;
    struct mail_private *mail;

    _mail = xpr_box->module_ctx.super.
        mail_alloc(t, wanted_fields, wanted_headers);
    mail = (struct mail_private *)_mail;

    xpr_mail = p_new(mail->pool, union mail_module_context, 1);
    xpr_mail->super = mail->v;

    mail->v.expunge = expire_mail_expunge;
    MODULE_CONTEXT_SET_SELF(mail, expire_mail_module, xpr_mail);
    return _mail;
}

static int expire_save_finish(struct mail_save_context *ctx)
{
    struct expire_transaction_context *xt =
        EXPIRE_CONTEXT(ctx->transaction);
    struct expire_mailbox *xpr_box = EXPIRE_CONTEXT(ctx->transaction->box);

    xt->saves = TRUE;
    return xpr_box->module_ctx.super.save_finish(ctx);
}

static int
expire_copy(struct mailbox_transaction_context *t, struct mail *mail,
        enum mail_flags flags, struct mail_keywords *keywords,
        struct mail *dest_mail)
{
    struct expire_transaction_context *xt = EXPIRE_CONTEXT(t);
    struct expire_mailbox *xpr_box = EXPIRE_CONTEXT(t->box);

    xt->saves = TRUE;
    return xpr_box->module_ctx.super.
        copy(t, mail, flags, keywords, dest_mail);
}

static void
mailbox_expire_hook(struct mailbox *box, time_t expire_secs, bool altmove)
{
    struct expire_mailbox *xpr_box;

    xpr_box = p_new(box->pool, struct expire_mailbox, 1);
    xpr_box->module_ctx.super = box->v;

    box->v.transaction_begin = expire_mailbox_transaction_begin;
    box->v.transaction_commit = expire_mailbox_transaction_commit;
    box->v.transaction_rollback = expire_mailbox_transaction_rollback;
    box->v.mail_alloc = expire_mail_alloc;
    box->v.save_finish = expire_save_finish;
    box->v.copy = expire_copy;

    xpr_box->altmove = altmove;
    xpr_box->expire_secs = expire_secs;

    MODULE_CONTEXT_SET(box, expire_storage_module, xpr_box);
}

static struct mailbox *
expire_mailbox_open(struct mail_storage *storage, const char *name,
            struct istream *input, enum mailbox_open_flags flags)
{
    union mail_storage_module_context *xpr_storage =
        EXPIRE_CONTEXT(storage);
    struct mailbox *box;
    string_t *vname;
    unsigned int secs;
    bool altmove;

    box = xpr_storage->super.mailbox_open(storage, name, input, flags);
    if (box != NULL) {
        vname = t_str_new(128);
        (void)mail_namespace_get_vname(storage->ns, vname, name);

        secs = expire_box_find_min_secs(expire.env, str_c(vname),
                        &altmove);
        if (secs != 0)
            mailbox_expire_hook(box, secs, altmove);
    }
    return box;
}

static void expire_mail_storage_created(struct mail_storage *storage)
{
    union mail_storage_module_context *xpr_storage;

    xpr_storage =
        p_new(storage->pool, union mail_storage_module_context, 1);
    xpr_storage->super = storage->v;
    storage->v.mailbox_open = expire_mailbox_open;

    MODULE_CONTEXT_SET_SELF(storage, expire_storage_module, xpr_storage);

    if (expire.next_hook_mail_storage_created != NULL)
        expire.next_hook_mail_storage_created(storage);
}

void expire_plugin_init(void)
{
    const char *expunge_env, *altmove_env, *dict_uri;

    expunge_env = getenv("EXPIRE");
    altmove_env = getenv("EXPIRE_ALTMOVE");
    if (expunge_env != NULL || altmove_env != NULL) {
        dict_uri = getenv("EXPIRE_DICT");
        if (dict_uri == NULL)
            i_fatal("expire plugin: expire_dict setting missing");

        expire.env = expire_env_init(expunge_env, altmove_env);
        /* we're using only shared dictionary, the username
           doesn't matter. */
        expire.db = dict_init(dict_uri, DICT_DATA_TYPE_UINT32, "");
        if (expire.db == NULL)
            i_fatal("expire plugin: dict_init() failed");

        expire.next_hook_mail_storage_created =
            hook_mail_storage_created;
        hook_mail_storage_created = expire_mail_storage_created;
    } else if (getenv("DEBUG") != NULL) {
        i_info("expire: No expire or expire_altmove settings - "
               "plugin disabled");
    }
}

void expire_plugin_deinit(void)
{
    if (expire.db != NULL) {
        hook_mail_storage_created =
            expire.next_hook_mail_storage_created;

        dict_deinit(&expire.db);
        expire_env_deinit(expire.env);
    }
}