path: root/camel/providers/local/camel-mbox-summary.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8; fill-column: 160 -*-
 *
 *  Copyright (C) 2000 Helix Code Inc.
 *
 *  Authors: Michael Zucchi <notzed@helixcode.com>
 *
 *  This program is free software; you can redistribute it and/or 
 *  modify it under the terms of the GNU General Public License as 
 *  published by the Free Software Foundation; either version 2 of the
 *  License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "camel-mbox-summary.h"
#include "camel/camel-mime-message.h"
#include "camel/camel-operation.h"

#include <sys/stat.h>
#include <sys/uio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>

#include "camel-mbox-summary.h"
#include "camel/camel-file-utils.h"
#include "camel/camel-mime-message.h"
#include "camel/camel-operation.h"

#define io(x)
#define d(x) /*(printf("%s(%d): ", __FILE__, __LINE__),(x))*/

#define CAMEL_MBOX_SUMMARY_VERSION (0x1000)

struct _CamelMboxSummaryPrivate {
};

#define _PRIVATE(o) (((CamelMboxSummary *)(o))->priv)

static int summary_header_load (CamelFolderSummary *, FILE *);
static int summary_header_save (CamelFolderSummary *, FILE *);

static CamelMessageInfo * message_info_new (CamelFolderSummary *, struct _header_raw *);
static CamelMessageInfo * message_info_new_from_parser (CamelFolderSummary *, CamelMimeParser *);
static CamelMessageInfo * message_info_load (CamelFolderSummary *, FILE *);
static int        message_info_save (CamelFolderSummary *, FILE *, CamelMessageInfo *);
/*static void         message_info_free (CamelFolderSummary *, CamelMessageInfo *);*/

static int mbox_summary_check(CamelLocalSummary *cls, CamelFolderChangeInfo *changeinfo, CamelException *ex);
static int mbox_summary_sync(CamelLocalSummary *cls, gboolean expunge, CamelFolderChangeInfo *changeinfo, CamelException *ex);

static void camel_mbox_summary_class_init (CamelMboxSummaryClass *klass);
static void camel_mbox_summary_init       (CamelMboxSummary *obj);
static void camel_mbox_summary_finalise   (CamelObject *obj);

static CamelLocalSummaryClass *camel_mbox_summary_parent;

CamelType
camel_mbox_summary_get_type(void)
{
    static CamelType type = CAMEL_INVALID_TYPE;
    
    if (type == CAMEL_INVALID_TYPE) {
        type = camel_type_register(camel_local_summary_get_type(), "CamelMboxSummary",
                       sizeof (CamelMboxSummary),
                       sizeof (CamelMboxSummaryClass),
                       (CamelObjectClassInitFunc) camel_mbox_summary_class_init,
                       NULL,
                       (CamelObjectInitFunc) camel_mbox_summary_init,
                       (CamelObjectFinalizeFunc) camel_mbox_summary_finalise);
    }
    
    return type;
}

static void
camel_mbox_summary_class_init(CamelMboxSummaryClass *klass)
{
    CamelFolderSummaryClass *sklass = (CamelFolderSummaryClass *)klass;
    CamelLocalSummaryClass *lklass = (CamelLocalSummaryClass *)klass;
    
    camel_mbox_summary_parent = (CamelLocalSummaryClass *)camel_type_get_global_classfuncs(camel_local_summary_get_type());

    sklass->summary_header_load = summary_header_load;
    sklass->summary_header_save = summary_header_save;

    sklass->message_info_new  = message_info_new;
    sklass->message_info_new_from_parser = message_info_new_from_parser;
    sklass->message_info_load = message_info_load;
    sklass->message_info_save = message_info_save;
    /*sklass->message_info_free = message_info_free;*/

    lklass->check = mbox_summary_check;
    lklass->sync = mbox_summary_sync;
}

static void
camel_mbox_summary_init(CamelMboxSummary *obj)
{
    struct _CamelMboxSummaryPrivate *p;
    struct _CamelFolderSummary *s = (CamelFolderSummary *)obj;

    p = _PRIVATE(obj) = g_malloc0(sizeof(*p));

    /* subclasses need to set the right instance data sizes */
    s->message_info_size = sizeof(CamelMboxMessageInfo);
    s->content_info_size = sizeof(CamelMboxMessageContentInfo);

    /* and a unique file version */
    s->version += CAMEL_MBOX_SUMMARY_VERSION;
}

static void
camel_mbox_summary_finalise(CamelObject *obj)
{
    /*CamelMboxSummary *mbs = CAMEL_MBOX_SUMMARY(obj);*/
}

/**
 * camel_mbox_summary_new:
 *
 * Create a new CamelMboxSummary object.
 * 
 * Return value: A new CamelMboxSummary widget.
 **/
CamelMboxSummary *
camel_mbox_summary_new(const char *filename, const char *mbox_name, ibex *index)
{
    CamelMboxSummary *new = (CamelMboxSummary *)camel_object_new(camel_mbox_summary_get_type());

    camel_local_summary_construct((CamelLocalSummary *)new, filename, mbox_name, index);
    return new;
}

static int
summary_header_load(CamelFolderSummary *s, FILE *in)
{
    CamelMboxSummary *mbs = CAMEL_MBOX_SUMMARY(s);

    if (((CamelFolderSummaryClass *)camel_mbox_summary_parent)->summary_header_load(s, in) == -1)
        return -1;

    return camel_file_util_decode_uint32(in, &mbs->folder_size);
}

static int
summary_header_save(CamelFolderSummary *s, FILE *out)
{
    CamelMboxSummary *mbs = CAMEL_MBOX_SUMMARY(s);

    if (((CamelFolderSummaryClass *)camel_mbox_summary_parent)->summary_header_save(s, out) == -1)
        return -1;

    return camel_file_util_encode_uint32(out, mbs->folder_size);
}

static CamelMessageInfo *
message_info_new(CamelFolderSummary *s, struct _header_raw *h)
{
    CamelMessageInfo *mi;

    mi = ((CamelFolderSummaryClass *)camel_mbox_summary_parent)->message_info_new(s, h);
    if (mi) {
        CamelMboxMessageInfo *mbi = (CamelMboxMessageInfo *)mi;

        mbi->frompos = -1;
    }
    
    return mi;
}

static CamelMessageInfo *
message_info_new_from_parser(CamelFolderSummary *s, CamelMimeParser *mp)
{
    CamelMessageInfo *mi;

    mi = ((CamelFolderSummaryClass *)camel_mbox_summary_parent)->message_info_new_from_parser(s, mp);
    if (mi) {
        CamelMboxMessageInfo *mbi = (CamelMboxMessageInfo *)mi;

        mbi->frompos = camel_mime_parser_tell_start_from(mp);
    }
    
    return mi;
}

static CamelMessageInfo *
message_info_load(CamelFolderSummary *s, FILE *in)
{
    CamelMessageInfo *mi;

    io(printf("loading mbox message info\n"));

    mi = ((CamelFolderSummaryClass *)camel_mbox_summary_parent)->message_info_load(s, in);
    if (mi) {
        CamelMboxMessageInfo *mbi = (CamelMboxMessageInfo *)mi;
        
        if (camel_file_util_decode_off_t(in, &mbi->frompos) == -1)
            goto error;
    }
    
    return mi;
error:
    camel_folder_summary_info_free(s, mi);
    return NULL;
}

static int
message_info_save(CamelFolderSummary *s, FILE *out, CamelMessageInfo *mi)
{
    CamelMboxMessageInfo *mbi = (CamelMboxMessageInfo *)mi;

    io(printf("saving mbox message info\n"));

    if (((CamelFolderSummaryClass *)camel_mbox_summary_parent)->message_info_save(s, out, mi) == -1
        || camel_file_util_encode_off_t(out, mbi->frompos) == -1)
        return -1;

    return 0;
}

static int
summary_rebuild(CamelMboxSummary *mbs, off_t offset, CamelException *ex)
{
    CamelLocalSummary *cls = (CamelLocalSummary *)mbs;
    CamelFolderSummary *s = (CamelFolderSummary *)mbs;
    CamelMimeParser *mp;
    int fd;
    int ok = 0;
    struct stat st;
    off_t size = 0;

    /* FIXME: If there is a failure, it shouldn't clear the summary and restart,
       it should try and merge the summary info's.  This is a bit tricky. */

    camel_operation_start(NULL, _("Summarising folder"));

    fd = open(cls->folder_path, O_RDONLY);
    if (fd == -1) {
        printf("%s failed to open: %s", cls->folder_path, strerror(errno));
        camel_exception_setv(ex, 1, _("Could not open folder: %s: summarising from position %ld: %s"),
                     cls->folder_path, offset, strerror(errno));
        camel_operation_end(NULL);
        return -1;
    }
    
    if (fstat(fd, &st) == 0)
        size = st.st_size;

    mp = camel_mime_parser_new();
    camel_mime_parser_init_with_fd(mp, fd);
    camel_mime_parser_scan_from(mp, TRUE);
    camel_mime_parser_seek(mp, offset, SEEK_SET);

    if (offset > 0) {
        if (camel_mime_parser_step(mp, NULL, NULL) == HSCAN_FROM) {
            if (camel_mime_parser_tell_start_from(mp) != offset) {
                g_warning("The next message didn't start where I expected, building summary from start");
                camel_mime_parser_drop_step(mp);
                offset = 0;
                camel_mime_parser_seek(mp, offset, SEEK_SET);
                camel_folder_summary_clear(s);
            } else {
                camel_mime_parser_unstep(mp);
            }
        } else {
            d(printf("mime parser state ran out? state is %d\n", camel_mime_parser_state(mp)));
            camel_object_unref(CAMEL_OBJECT(mp));
            /* end of file - no content? no error either */
            camel_operation_end(NULL);
            return 0;
        }
    }

    while (camel_mime_parser_step(mp, NULL, NULL) == HSCAN_FROM) {
        CamelMessageInfo *info;
        off_t pc = camel_mime_parser_tell_start_from (mp) + 1;
        
        camel_operation_progress (NULL, (int) (((float) pc / size) * 100));
        
        info = camel_folder_summary_add_from_parser(s, mp);
        if (info == NULL) {
            camel_exception_setv(ex, 1, _("Fatal mail parser error near position %ld in folder %s"),
                         camel_mime_parser_tell(mp), cls->folder_path);
            ok = -1;
            break;
        }

        g_assert(camel_mime_parser_step(mp, NULL, NULL) == HSCAN_FROM_END);
    }

    camel_object_unref(CAMEL_OBJECT (mp));
    
    /* update the file size/mtime in the summary */
    if (ok != -1) {
        if (stat(cls->folder_path, &st) == 0) {
            camel_folder_summary_touch(s);
            mbs->folder_size = st.st_size;
            s->time = st.st_mtime;
        }
    }

    camel_operation_end(NULL);

    return ok;
}

/* like summary_rebuild, but also do changeinfo stuff (if supplied) */
static int
summary_update(CamelLocalSummary *cls, off_t offset, CamelFolderChangeInfo *changeinfo, CamelException *ex)
{
    int ret, i, count;
    CamelFolderSummary *s = (CamelFolderSummary *)cls;
    CamelMboxSummary *mbs = (CamelMboxSummary *)cls;

    d(printf("Calling summary update, from pos %d\n", (int)offset));

    if (changeinfo) {
        /* we use the diff function of the change_info to build the update list. */
        for (i = 0; i < camel_folder_summary_count(s); i++) {
            CamelMessageInfo *mi = camel_folder_summary_index(s, i);

            camel_folder_change_info_add_source(changeinfo, camel_message_info_uid(mi));
            camel_folder_summary_info_free(s, mi);
        }
    }

    /* do the actual work */
    cls->index_force = FALSE;
    ret = summary_rebuild(mbs, offset, ex);

    if (changeinfo) {
        count = camel_folder_summary_count(s);
        for (i = 0; i < count; i++) {
            CamelMessageInfo *mi = camel_folder_summary_index(s, i);
            camel_folder_change_info_add_update(changeinfo, camel_message_info_uid(mi));
            camel_folder_summary_info_free(s, mi);
        }
        camel_folder_change_info_build_diff(changeinfo);
    }

    return ret;
}

static int
mbox_summary_check(CamelLocalSummary *cls, CamelFolderChangeInfo *changes, CamelException *ex)
{
    CamelMboxSummary *mbs = (CamelMboxSummary *)cls;
    CamelFolderSummary *s = (CamelFolderSummary *)cls;
    struct stat st;
    int ret = 0;

    d(printf("Checking summary\n"));

    /* check if the summary is up-to-date */
    if (stat(cls->folder_path, &st) == -1) {
        camel_folder_summary_clear(s);
        camel_exception_setv(ex, 1, _("Cannot summarise folder: %s: %s"), cls->folder_path, strerror(errno));
        return -1;
    }

    if (st.st_size == 0) {
        /* empty?  No need to scan at all */
        d(printf("Empty mbox, clearing summary\n"));
        camel_folder_summary_clear(s);
        ret = 0;
    } else if (s->messages->len == 0) {
        /* if we are empty, then we rebuilt from scratch */
        d(printf("Empty summary, rebuilding from start\n"));
        ret = summary_update(cls, 0, changes, ex);
    } else {
        /* is the summary uptodate? */
        if (st.st_size != mbs->folder_size || st.st_mtime != s->time) {
            if (mbs->folder_size < st.st_size) {
                /* this will automatically rescan from 0 if there is a problem */
                d(printf("folder grew, attempting to rebuild from %d\n", mbs->folder_size));
                ret = summary_update(cls, mbs->folder_size, changes, ex);
            } else {
                d(printf("folder shrank!  rebuilding from start\n"));
                camel_folder_summary_clear(s);
                ret = summary_update(cls, 0, changes, ex);
            }
        }
    }

    /* FIXME: move upstream? */

    if (ret != -1) {
        mbs->folder_size = st.st_size;
        s->time = st.st_mtime;
#if 0
        /* this failing is not a fatal event */
        if (camel_folder_summary_save(s) == -1)
            g_warning("Could not save summary: %s", strerror(errno));
        if (cls->index)
            ibex_save(cls->index);
#endif
    }

    return ret;
}

static char *tz_months[] = {
    "Jan", "Feb", "Mar", "Apr", "May", "Jun",
    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};

static char *tz_days[] = {
    "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};

/* tries to build a From line, based on message headers */
char *
camel_mbox_summary_build_from(struct _header_raw *header)
{
    GString *out = g_string_new("From ");
    char *ret;
    const char *tmp;
    time_t thetime;
    int offset;
    struct tm tm;

    tmp = header_raw_find(&header, "Sender", NULL);
    if (tmp == NULL)
        tmp = header_raw_find(&header, "From", NULL);
    if (tmp != NULL) {
        struct _header_address *addr = header_address_decode(tmp);

        tmp = NULL;
        if (addr) {
            if (addr->type == HEADER_ADDRESS_NAME) {
                g_string_append(out, addr->v.addr);
                tmp = "";
            }
            header_address_unref(addr);
        }
    }
    if (tmp == NULL) {
        g_string_append(out, "unknown@nodomain.now.au");
    }

    /* try use the received header to get the date */
    tmp = header_raw_find(&header, "Received", NULL);
    if (tmp) {
        tmp = strrchr(tmp, ';');
        if (tmp)
            tmp++;
    }

    /* if there isn't one, try the Date field */
    if (tmp == NULL)
        tmp = header_raw_find(&header, "Date", NULL);

    thetime = header_decode_date(tmp, &offset);

    thetime += ((offset / 100) * (60 * 60)) + (offset % 100) * 60;

    /* a pseudo, but still bogus attempt at thread safing the function */
    /*memcpy(&tm, gmtime(&thetime), sizeof(tm));*/
    gmtime_r(&thetime, &tm);

    g_string_sprintfa(out, " %s %s %d %02d:%02d:%02d %4d\n",
              tz_days[tm.tm_wday],
              tz_months[tm.tm_mon], tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec, tm.tm_year + 1900);

    ret = out->str;
    g_string_free(out, FALSE);
    return ret;
}

/* perform a full sync */
static int
mbox_summary_sync_full(CamelLocalSummary *cls, gboolean expunge, CamelFolderChangeInfo *changeinfo, CamelException *ex)
{
    CamelMboxSummary *mbs = (CamelMboxSummary *)cls;
    CamelFolderSummary *s = (CamelFolderSummary *)mbs;
    CamelMimeParser *mp = NULL;
    int i, count;
    CamelMboxMessageInfo *info = NULL;
    int fd = -1, fdout = -1;
    char *tmpname = NULL;
    char *buffer, *xevnew = NULL;
    int len;
    const char *fromline;
    int lastdel = FALSE;

    d(printf("performing full summary/sync\n"));

    camel_operation_start(NULL, _("Synchronising folder"));

    fd = open(cls->folder_path, O_RDONLY);
    if (fd == -1) {
        camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Could not open folder to summarise: %s: %s"),
                     cls->folder_path, strerror(errno));
        camel_operation_end(NULL);
        return -1;
    }

    mp = camel_mime_parser_new();
    camel_mime_parser_scan_from(mp, TRUE);
    camel_mime_parser_scan_pre_from(mp, TRUE);
    camel_mime_parser_init_with_fd(mp, fd);

    tmpname = alloca(strlen (cls->folder_path) + 5);
    sprintf(tmpname, "%s.tmp", cls->folder_path);
    d(printf("Writing tmp file to %s\n", tmpname));
    fdout = open(tmpname, O_WRONLY|O_CREAT|O_TRUNC, 0600);
    if (fdout == -1) {
        camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Cannot open temporary mailbox: %s"), strerror(errno));
        goto error;
    }

    count = camel_folder_summary_count(s);
    for (i = 0; i < count; i++) {
        int pc = (i + 1) * 100 / count;

        camel_operation_progress(NULL, pc);

        info = (CamelMboxMessageInfo *)camel_folder_summary_index(s, i);

        g_assert(info);

        d(printf("Looking at message %s\n", info->info.uid));

        /* only need to seek past deleted messages, otherwise we should be at the right spot/state already */
        if (lastdel) {
            d(printf("seeking to %d\n", (int)info->frompos));
            camel_mime_parser_seek(mp, info->frompos, SEEK_SET);
        }

        if (camel_mime_parser_step(mp, &buffer, &len) != HSCAN_FROM) {
            g_warning("Expected a From line here, didn't get it");
            camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                         _("Summary and folder mismatch, even after a sync"));
            goto error;
        }

        if (camel_mime_parser_tell_start_from(mp) != info->frompos) {
            g_warning("Didn't get the next message where I expected (%d) got %d instead",
                  (int)info->frompos, (int)camel_mime_parser_tell_start_from(mp));
            camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                         _("Summary and folder mismatch, even after a sync"));
            goto error;
        }

        lastdel = FALSE;
        if (expunge && info->info.flags & CAMEL_MESSAGE_DELETED) {
            const char *uid = camel_message_info_uid(info);

            d(printf("Deleting %s\n", uid));

            if (cls->index)
                ibex_unindex(cls->index, (char *)uid);

            /* remove it from the change list */
            camel_folder_change_info_remove_uid(changeinfo, uid);
            camel_folder_summary_remove(s, (CamelMessageInfo *)info);
            camel_folder_summary_info_free(s, (CamelMessageInfo *)info);
            count--;
            i--;
            info = NULL;
            lastdel = TRUE;
        } else {
            /* otherwise, the message is staying, copy its From_ line across */
            if (i>0) {
                write(fdout, "\n", 1);
            }
            info->frompos = lseek(fdout, 0, SEEK_CUR);
            fromline = camel_mime_parser_from_line(mp);
            write(fdout, fromline, strlen(fromline));
        }

        if (info && info->info.flags & (CAMEL_MESSAGE_FOLDER_NOXEV | CAMEL_MESSAGE_FOLDER_FLAGGED)) {
            d(printf("Updating header for %s flags = %08x\n", info->info.uid, info->info.flags));

            if (camel_mime_parser_step(mp, &buffer, &len) == HSCAN_FROM_END) {
                g_warning("camel_mime_parser_step failed (2)");
                goto error;
            }

            xevnew = camel_local_summary_encode_x_evolution(cls, (CamelMessageInfo *)info);
            if (camel_local_summary_write_headers(fdout, camel_mime_parser_headers_raw(mp), xevnew) == -1) {
                d(printf("Error writing to tmp mailbox\n"));
                camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                             _("Error writing to temp mailbox: %s"),
                             strerror(errno));
                goto error;
            }
            info->info.flags &= 0xffff;
            g_free(xevnew);
            xevnew = NULL;
            camel_mime_parser_drop_step(mp);
        }

        camel_mime_parser_drop_step(mp);
        if (info) {
            d(printf("looking for message content to copy across from %d\n", (int)camel_mime_parser_tell(mp)));
            while (camel_mime_parser_step(mp, &buffer, &len) == HSCAN_PRE_FROM) {
                d(printf("copying mbox contents to tmp: '%.*s'\n", len, buffer));
                if (write(fdout, buffer, len) != len) {
                    camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                                 _("Writing to tmp mailbox failed: %s: %s"),
                                 cls->folder_path, strerror(errno));
                    goto error;
                }
            }
            d(printf("we are now at %d, from = %d\n", (int)camel_mime_parser_tell(mp),
                 (int)camel_mime_parser_tell_start_from(mp)));
            camel_mime_parser_unstep(mp);
            camel_folder_summary_info_free(s, (CamelMessageInfo *)info);
            info = NULL;
        }
    }

    d(printf("Closing folders\n"));

    if (close(fd) == -1) {
        g_warning("Cannot close source folder: %s", strerror(errno));
        camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Could not close source folder %s: %s"),
                     cls->folder_path, strerror(errno));
        fd = -1;
        goto error;
    }

    if (close(fdout) == -1) {
        g_warning("Cannot close tmp folder: %s", strerror(errno));
        camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Could not close temp folder: %s"),
                     strerror(errno));
        fdout = -1;
        goto error;
    }

    /* this should probably either use unlink/link/unlink, or recopy over
       the original mailbox, for various locking reasons/etc */
    if (rename(tmpname, cls->folder_path) == -1) {
        g_warning("Cannot rename folder: %s", strerror(errno));
        camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Could not rename folder: %s"),
                     strerror(errno));
        goto error;
    }
    tmpname = NULL;

    camel_object_unref((CamelObject *)mp);
    camel_operation_end(NULL);
        
    return 0;
 error:
    if (fd != -1)
        close(fd);
    
    if (fdout != -1)
        close(fdout);
    
    g_free(xevnew);
    
    if (tmpname)
        unlink(tmpname);
    if (mp)
        camel_object_unref((CamelObject *)mp);
    if (info)
        camel_folder_summary_info_free(s, (CamelMessageInfo *)info);

    camel_operation_end(NULL);

    return -1;
}

/* perform a quick sync - only system flags have changed */
static int
mbox_summary_sync_quick(CamelLocalSummary *cls, gboolean expunge, CamelFolderChangeInfo *changeinfo, CamelException *ex)
{
    CamelMboxSummary *mbs = (CamelMboxSummary *)cls;
    CamelFolderSummary *s = (CamelFolderSummary *)mbs;
    CamelMimeParser *mp = NULL;
    int i, count;
    CamelMboxMessageInfo *info = NULL;
    int fd = -1;
    char *xevnew, *xevtmp;
    const char *xev;
    int len;
    off_t lastpos;

    d(printf("Performing quick summary sync\n"));

    camel_operation_start(NULL, _("Synchronising folder"));

    fd = open(cls->folder_path, O_RDWR);
    if (fd == -1) {
        camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Could not open folder to summarise: %s: %s"),
                     cls->folder_path, strerror(errno));

        camel_operation_end(NULL);
        return -1;
    }

    mp = camel_mime_parser_new();
    camel_mime_parser_scan_from(mp, TRUE);
    camel_mime_parser_scan_pre_from(mp, TRUE);
    camel_mime_parser_init_with_fd(mp, fd);

    count = camel_folder_summary_count(s);
    for (i = 0; i < count; i++) {
        int xevoffset;
        int pc = (i+1)*100/count;

        camel_operation_progress(NULL, pc);

        info = (CamelMboxMessageInfo *)camel_folder_summary_index(s, i);

        g_assert(info);

        d(printf("Checking message %s %08x\n", info->info.uid, info->info.flags));

        if ((info->info.flags & CAMEL_MESSAGE_FOLDER_FLAGGED) == 0) {
            camel_folder_summary_info_free(s, (CamelMessageInfo *)info);
            info = NULL;
            continue;
        }

        d(printf("Updating message %s\n", info->info.uid));

        camel_mime_parser_seek(mp, info->frompos, SEEK_SET);

        if (camel_mime_parser_step(mp, 0, 0) != HSCAN_FROM) {
            g_warning("Expected a From line here, didn't get it");
            camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                         _("Summary and folder mismatch, even after a sync"));
            goto error;
        }

        if (camel_mime_parser_tell_start_from(mp) != info->frompos) {
            g_warning("Didn't get the next message where I expected (%d) got %d instead",
                  (int)info->frompos, (int)camel_mime_parser_tell_start_from(mp));
            camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                         _("Summary and folder mismatch, even after a sync"));
            goto error;
        }

        if (camel_mime_parser_step(mp, 0, 0) == HSCAN_FROM_END) {
            g_warning("camel_mime_parser_step failed (2)");
            goto error;
        }

        xev = camel_mime_parser_header(mp, "X-Evolution", &xevoffset);
        if (xev == NULL || camel_local_summary_decode_x_evolution(cls, xev, NULL) == -1) {
            g_warning("We're supposed to have a valid x-ev header, but we dont");
            goto error;
        }
        xevnew = camel_local_summary_encode_x_evolution(cls, (CamelMessageInfo *)info);
        /* SIGH: encode_param_list is about the only function which folds headers by itself.
           This should be fixed somehow differently (either parser doesn't fold headers,
           or param_list doesn't, or something */
        xevtmp = header_unfold(xevnew);
        /* the raw header contains a leading ' ', so (dis)count that too */
        if (strlen(xev)-1 != strlen(xevtmp)) {
            g_free(xevnew);
            g_free(xevtmp);
            g_warning("Hmm, the xev headers shouldn't have changed size, but they did");
            goto error;
        }
        g_free(xevtmp);

        /* we write out the xevnew string, assuming its been folded identically to the original too! */

        lastpos = lseek(fd, 0, SEEK_CUR);
        lseek(fd, xevoffset+strlen("X-Evolution: "), SEEK_SET);
        do {
            len = write(fd, xevnew, strlen(xevnew));
        } while (len == -1 && errno == EINTR);
        lseek(fd, lastpos, SEEK_SET);
        g_free(xevnew);

        camel_mime_parser_drop_step(mp);
        camel_mime_parser_drop_step(mp);

        info->info.flags &= 0xffff;
        camel_folder_summary_info_free(s, (CamelMessageInfo *)info);
    }

    d(printf("Closing folders\n"));

    if (close(fd) == -1) {
        g_warning("Cannot close source folder: %s", strerror(errno));
        camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Could not close source folder %s: %s"),
                     cls->folder_path, strerror(errno));
        fd = -1;
        goto error;
    }

    camel_object_unref((CamelObject *)mp);

    camel_operation_end(NULL);
    
    return 0;
 error:
    if (fd != -1)
        close(fd);
    if (mp)
        camel_object_unref((CamelObject *)mp);
    if (info)
        camel_folder_summary_info_free(s, (CamelMessageInfo *)info);

    camel_operation_end(NULL);

    return -1;
}

static int
mbox_summary_sync(CamelLocalSummary *cls, gboolean expunge, CamelFolderChangeInfo *changeinfo, CamelException *ex)
{
    struct stat st;
    CamelMboxSummary *mbs = (CamelMboxSummary *)cls;
    CamelFolderSummary *s = (CamelFolderSummary *)cls;
    int i, count;
    int quick = TRUE, work=FALSE;
    int ret;

    /* first, sync ourselves up, just to make sure */
    summary_update(cls, mbs->folder_size, changeinfo, ex);
    if (camel_exception_is_set(ex))
        return -1;

    count = camel_folder_summary_count(s);
    if (count == 0)
        return 0;

    /* check what work we have to do, if any */
    for (i=0;quick && i<count; i++) {
        CamelMessageInfo *info = camel_folder_summary_index(s, i);
        g_assert(info);
        if ((expunge && (info->flags & CAMEL_MESSAGE_DELETED)) ||
            (info->flags & (CAMEL_MESSAGE_FOLDER_NOXEV|CAMEL_MESSAGE_FOLDER_XEVCHANGE)))
            quick = FALSE;
        else
            work |= (info->flags & CAMEL_MESSAGE_FOLDER_FLAGGED) != 0;
        camel_folder_summary_info_free(s, info);
    }

    /* yuck i hate this logic, but its to simplify the 'all ok, update summary' and failover cases */
    ret = -1;
    if (quick) {
        if (work) {
            ret = mbox_summary_sync_quick(cls, expunge, changeinfo, ex);
            if (ret == -1) {
                g_warning("failed a quick-sync, trying a full sync");
                camel_exception_clear(ex);
            }
        } else {
            ret = 0;
        }
    }

    if (ret == -1)
        ret = mbox_summary_sync_full(cls, expunge, changeinfo, ex);
    if (ret == -1)
        return -1;

    if (stat(cls->folder_path, &st) == -1) {
        camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM, _("Unknown error: %s"), strerror(errno));
        return -1;
    }

    camel_folder_summary_touch(s);
    s->time = st.st_mtime;
    mbs->folder_size = st.st_size;
    camel_folder_summary_save(s);

    return 0;
}