path: root/mail/em-format.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 *  Authors: Michael Zucchi <notzed@ximian.com>
 *           Jeffrey Stedfast <fejj@ximian.com>
 *
 *  Copyright 2003 Ximian, Inc. (www.ximian.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 Street #330, Boston, MA 02111-1307, USA.
 *
 */

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

#include <stdio.h>
#include <string.h>

#include <libgnomevfs/gnome-vfs-mime.h>
#include <libgnomevfs/gnome-vfs-mime-utils.h>
#include <libgnomevfs/gnome-vfs-mime-handlers.h>
#include <libgnome/gnome-i18n.h>

#include <libedataserver/e-msgport.h>
#include <camel/camel-url.h>
#include <camel/camel-stream.h>
#include <camel/camel-stream-mem.h>
#include <camel/camel-multipart.h>
#include <camel/camel-multipart-encrypted.h>
#include <camel/camel-multipart-signed.h>
#include <camel/camel-medium.h>
#include <camel/camel-mime-message.h>
#include <camel/camel-gpg-context.h>
#include <camel/camel-smime-context.h>
#include <camel/camel-string-utils.h>
#include <camel/camel-stream-filter.h>
#include <camel/camel-stream-null.h>
#include <camel/camel-mime-filter-charset.h>
#include <camel/camel-mime-filter-windows.h>

#include "em-format.h"
#include "em-utils.h"

#define d(x) 

/* Used to cache various data/info for redraws
   The validity stuff could be cached at a higher level but this is easier
   This absolutely relies on the partid being _globally unique_
   This is still kind of yucky, we should maintian a full tree of all this data,
   along with/as part of the puri tree */
struct _EMFormatCache {
    struct _CamelCipherValidity *valid; /* validity copy */
    struct _CamelMimePart *secured; /* encrypted subpart */

    unsigned int state:2;       /* inline state */

    char partid[1];
};

#define INLINE_UNSET (0)
#define INLINE_ON (1)
#define INLINE_OFF (2)

static void emf_builtin_init(EMFormatClass *);

static const EMFormatHandler *emf_find_handler(EMFormat *emf, const char *mime_type);
static void emf_format_clone(EMFormat *emf, CamelFolder *folder, const char *uid, CamelMimeMessage *msg, EMFormat *emfsource);
static void emf_format_secure(EMFormat *emf, CamelStream *stream, CamelMimePart *part, CamelCipherValidity *valid);
static gboolean emf_busy(EMFormat *emf);

enum {
    EMF_COMPLETE,
    EMF_LAST_SIGNAL,
};

static guint emf_signals[EMF_LAST_SIGNAL];
static GObjectClass *emf_parent;

static void
emf_free_cache(void *key, void *val, void *dat)
{
    struct _EMFormatCache *efc = val;

    if (efc->valid)
        camel_cipher_validity_free(efc->valid);
    if (efc->secured)
        camel_object_unref(efc->secured);
    g_free(efc);
}

static struct _EMFormatCache *
emf_insert_cache(EMFormat *emf, const char *partid)
{
    struct _EMFormatCache *new;

    new = g_malloc0(sizeof(*new)+strlen(partid));
    strcpy(new->partid, partid);
    g_hash_table_insert(emf->inline_table, new->partid, new);

    return new;
}

static void
emf_init(GObject *o)
{
    EMFormat *emf = (EMFormat *)o;
    
    emf->inline_table = g_hash_table_new(g_str_hash, g_str_equal);
    e_dlist_init(&emf->header_list);
    em_format_default_headers(emf);
    emf->part_id = g_string_new("");
}

static void
emf_finalise(GObject *o)
{
    EMFormat *emf = (EMFormat *)o;
    
    if (emf->session)
        camel_object_unref(emf->session);

    g_hash_table_foreach(emf->inline_table, emf_free_cache, NULL);
    g_hash_table_destroy(emf->inline_table);

    em_format_clear_headers(emf);
    camel_cipher_validity_free(emf->valid);
    g_free(emf->charset);
    g_free (emf->default_charset);
    g_string_free(emf->part_id, TRUE);

    /* FIXME: check pending jobs */
    
    ((GObjectClass *)emf_parent)->finalize(o);
}

static void
emf_base_init(EMFormatClass *emfklass)
{
    emfklass->type_handlers = g_hash_table_new(g_str_hash, g_str_equal);
    emf_builtin_init(emfklass);
}

static void
emf_class_init(GObjectClass *klass)
{
    ((EMFormatClass *)klass)->type_handlers = g_hash_table_new(g_str_hash, g_str_equal);
    emf_builtin_init((EMFormatClass *)klass);

    klass->finalize = emf_finalise;
    ((EMFormatClass *)klass)->find_handler = emf_find_handler;
    ((EMFormatClass *)klass)->format_clone = emf_format_clone;
    ((EMFormatClass *)klass)->format_secure = emf_format_secure;
    ((EMFormatClass *)klass)->busy = emf_busy;

    emf_signals[EMF_COMPLETE] =
        g_signal_new("complete",
                 G_OBJECT_CLASS_TYPE (klass),
                 G_SIGNAL_RUN_LAST,
                 G_STRUCT_OFFSET (EMFormatClass, complete),
                 NULL, NULL,
                 g_cclosure_marshal_VOID__VOID,
                 G_TYPE_NONE, 0);
}

GType
em_format_get_type(void)
{
    static GType type = 0;

    if (type == 0) {
        static const GTypeInfo info = {
            sizeof(EMFormatClass),
            (GBaseInitFunc)emf_base_init, NULL,
            (GClassInitFunc)emf_class_init,
            NULL, NULL,
            sizeof(EMFormat), 0,
            (GInstanceInitFunc)emf_init
        };
        emf_parent = g_type_class_ref(G_TYPE_OBJECT);
        type = g_type_register_static(G_TYPE_OBJECT, "EMFormat", &info, 0);
    }

    return type;
}

/**
 * em_format_class_add_handler:
 * @emfc: EMFormatClass
 * @info: Callback information.
 * 
 * Add a mime type handler to this class.  This is only used by
 * implementing classes.  The @info.old pointer will automatically be
 * setup to point to the old hanlder if one was already set.  This can
 * be used for overrides a fallback.
 *
 * When a mime type described by @info is encountered, the callback will
 * be invoked.  Note that @info may be extended by sub-classes if
 * they require additional context information.
 *
 * Use a mime type of "foo/ *" to insert a fallback handler for type "foo".
 **/
void
em_format_class_add_handler(EMFormatClass *emfc, EMFormatHandler *info)
{
    d(printf("adding format handler to '%s' '%s'\n",    g_type_name_from_class((GTypeClass *)emfc), info->mime_type));
    info->old = g_hash_table_lookup(emfc->type_handlers, info->mime_type);
    g_hash_table_insert(emfc->type_handlers, info->mime_type, info);
}

/**
 * em_format_class_remove_handler:
 * @emfc: 
 * @info: 
 * 
 * Remove a handler.  @info must be a value which was previously
 * added.
 **/
void
em_format_class_remove_handler(EMFormatClass *emfc, EMFormatHandler *info)
{
    EMFormatHandler *current;

    /* TODO: thread issues? */

    current = g_hash_table_lookup(emfc->type_handlers, info->mime_type);
    if (current == info) {
        current = info->old;
        if (current)
            g_hash_table_insert(emfc->type_handlers, current->mime_type, current);
        else
            g_hash_table_remove(emfc->type_handlers, info->mime_type);
    } else {
        while (current && current->old != info)
            current = current->old;
        g_return_if_fail(current != NULL);
        current->old = info->old;
    }
}

/**
 * em_format_find_handler:
 * @emf: 
 * @mime_type: 
 * 
 * Find a format handler by @mime_type.
 * 
 * Return value: NULL if no handler is available.
 **/
static const EMFormatHandler *
emf_find_handler(EMFormat *emf, const char *mime_type)
{
    EMFormatClass *emfc = (EMFormatClass *)G_OBJECT_GET_CLASS(emf);

    return g_hash_table_lookup(emfc->type_handlers, mime_type);
}

/**
 * em_format_fallback_handler:
 * @emf: 
 * @mime_type: 
 * 
 * Try to find a format handler based on the major type of the @mime_type.
 *
 * The subtype is replaced with "*" and a lookup performed.
 * 
 * Return value: 
 **/
const EMFormatHandler *
em_format_fallback_handler(EMFormat *emf, const char *mime_type)
{
    char *mime, *s;

    s = strchr(mime_type, '/');
    if (s == NULL)
        mime = (char *)mime_type;
    else {
        size_t len = (s-mime_type)+1;

        mime = alloca(len+2);
        strncpy(mime, mime_type, len);
        strcpy(mime+len, "*");
    }

    return em_format_find_handler(emf, mime);
}

/**
 * em_format_add_puri:
 * @emf: 
 * @size: 
 * @cid: Override the autogenerated content id.
 * @part: 
 * @func: 
 * 
 * Add a pending-uri handler.  When formatting parts that reference
 * other parts, a pending-uri (PURI) can be used to track the reference.
 *
 * @size is used to allocate the structure, so that it can be directly
 * subclassed by implementors.
 * 
 * @cid can be used to override the key used to retreive the PURI, if NULL,
 * then the content-location and the content-id of the @part are stored
 * as lookup keys for the part.
 *
 * FIXME: This may need a free callback.
 *
 * Return value: A new PURI, with a referenced copy of @part, and the cid
 * always set.  The uri will be set if one is available.  Clashes
 * are resolved by forgetting the old PURI in the global index.
 **/
EMFormatPURI *
em_format_add_puri(EMFormat *emf, size_t size, const char *cid, CamelMimePart *part, EMFormatPURIFunc func)
{
    EMFormatPURI *puri;
    const char *tmp;

    d(printf("adding puri for part: %s\n", emf->part_id->str));

    g_assert(size >= sizeof(*puri));
    puri = g_malloc0(size);

    puri->format = emf;
    puri->func = func;
    puri->use_count = 0;
    puri->cid = g_strdup(cid);
    puri->part_id = g_strdup(emf->part_id->str);

    if (part) {
        camel_object_ref(part);
        puri->part = part;
    }

    if (part != NULL && cid == NULL) {
        tmp = camel_mime_part_get_content_id(part);
        if (tmp)
            puri->cid = g_strdup_printf("cid:%s", tmp);
        else
            puri->cid = g_strdup_printf("em-no-cid:%s", emf->part_id->str);

        d(printf("built cid '%s'\n", puri->cid));

        /* not quite same as old behaviour, it also put in the relative uri and a fallback for no parent uri */
        tmp = camel_mime_part_get_content_location(part);
        puri->uri = NULL;
        if (tmp == NULL) {
            /* no location, don't set a uri at all, html parts do this themselves */
        } else {
            if (strchr(tmp, ':') == NULL && emf->base != NULL) {
                CamelURL *uri;

                uri = camel_url_new_with_base(emf->base, tmp);
                puri->uri = camel_url_to_string(uri, 0);
                camel_url_free(uri);
            } else {
                puri->uri = g_strdup(tmp);
            }
        }
    }

    g_assert(puri->cid != NULL);
    g_assert(emf->pending_uri_level != NULL);
    g_assert(emf->pending_uri_table != NULL);

    e_dlist_addtail(&emf->pending_uri_level->uri_list, (EDListNode *)puri);

    if (puri->uri)
        g_hash_table_insert(emf->pending_uri_table, puri->uri, puri);
    g_hash_table_insert(emf->pending_uri_table, puri->cid, puri);

    return puri;
}

/**
 * em_format_push_level:
 * @emf: 
 * 
 * This is used to build a heirarchy of visible PURI objects based on
 * the structure of the message.  Used by multipart/alternative formatter.
 *
 * FIXME: This could probably also take a uri so it can automaticall update
 * the base location.
 **/
void
em_format_push_level(EMFormat *emf)
{
    struct _EMFormatPURITree *purilist;

    d(printf("em_format_push_level\n"));
    purilist = g_malloc0(sizeof(*purilist));
    e_dlist_init(&purilist->children);
    e_dlist_init(&purilist->uri_list);
    purilist->parent = emf->pending_uri_level;
    if (emf->pending_uri_tree == NULL) {
        emf->pending_uri_tree = purilist;
    } else {
        e_dlist_addtail(&emf->pending_uri_level->children, (EDListNode *)purilist);
    }
    emf->pending_uri_level = purilist;
}

/**
 * em_format_pull_level:
 * @emf: 
 * 
 * Drop a level of visibility back to the parent.  Note that
 * no PURI values are actually freed.
 **/
void
em_format_pull_level(EMFormat *emf)
{
    d(printf("em_format_pull_level\n"));
    emf->pending_uri_level = emf->pending_uri_level->parent;
}

/**
 * em_format_find_visible_puri:
 * @emf: 
 * @uri: 
 * 
 * Search for a PURI based on the visibility defined by :push_level()
 * and :pull_level().
 * 
 * Return value: 
 **/
EMFormatPURI *
em_format_find_visible_puri(EMFormat *emf, const char *uri)
{
    EMFormatPURI *pw;
    struct _EMFormatPURITree *ptree;

    d(printf("checking for visible uri '%s'\n", uri));

    ptree = emf->pending_uri_level;
    while (ptree) {
        pw = (EMFormatPURI *)ptree->uri_list.head;
        while (pw->next) {
            d(printf(" pw->uri = '%s' pw->cid = '%s\n", pw->uri?pw->uri:"", pw->cid));
            if ((pw->uri && !strcmp(pw->uri, uri)) || !strcmp(pw->cid, uri))
                return pw;
            pw = pw->next;
        }
        ptree = ptree->parent;
    }

    return NULL;
}

/**
 * em_format_find_puri:
 * @emf: 
 * @uri: 
 * 
 * Search for a PURI based on a uri.  Both the content-id
 * and content-location are checked.
 * 
 * Return value: 
 **/
EMFormatPURI *
em_format_find_puri(EMFormat *emf, const char *uri)
{
    return g_hash_table_lookup(emf->pending_uri_table, uri);
}

static void
emf_clear_puri_node(struct _EMFormatPURITree *node)
{
    {
        EMFormatPURI *pw, *pn;

        /* clear puri's at this level */
        pw = (EMFormatPURI *)node->uri_list.head;
        pn = pw->next;
        while (pn) {
            if (pw->free)
                pw->free(pw);
            g_free(pw->uri);
            g_free(pw->cid);
            g_free(pw->part_id);
            if (pw->part)
                camel_object_unref(pw->part);
            g_free(pw);
            pw = pn;
            pn = pn->next;
        }
    }

    {
        struct _EMFormatPURITree *cw, *cn;

        /* clear child nodes */
        cw = (struct _EMFormatPURITree *)node->children.head;
        cn = cw->next;
        while (cn) {
            emf_clear_puri_node(cw);
            cw = cn;
            cn = cn->next;
        }
    }

    g_free(node);
}

/**
 * em_format_clear_puri_tree:
 * @emf: 
 * 
 * For use by implementors to clear out the message structure
 * data.
 **/
void
em_format_clear_puri_tree(EMFormat *emf)
{
    d(printf("clearing pending uri's\n"));

    if (emf->pending_uri_table) {
        g_hash_table_destroy(emf->pending_uri_table);
        emf_clear_puri_node(emf->pending_uri_tree);
        emf->pending_uri_level = NULL;
        emf->pending_uri_tree = NULL;
    }
    emf->pending_uri_table = g_hash_table_new(g_str_hash, g_str_equal);
    em_format_push_level(emf);
}

/* use mime_type == NULL  to force showing as application/octet-stream */
void
em_format_part_as(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const char *mime_type)
{
    const EMFormatHandler *handle = NULL;
    const char *snoop_save = emf->snoop_mime_type, *tmp;
    CamelURL *base_save = emf->base, *base = NULL;
    char *basestr = NULL;

    d(printf("format_part_as()\n"));

    emf->snoop_mime_type = NULL;

    /* RFC 2110, we keep track of content-base, and absolute content-location headers
       This is actually only required for html, but, *shrug* */
    tmp = camel_medium_get_header((CamelMedium *)part, "Content-Base");
    if (tmp == NULL) {
        tmp = camel_mime_part_get_content_location(part);
        if (tmp && strchr(tmp, ':') == NULL)
            tmp = NULL;
    } else {
        tmp = basestr = camel_header_location_decode(tmp);
    }
    d(printf("content-base is '%s'\n", tmp?tmp:"<unset>"));
    if (tmp
        && (base = camel_url_new(tmp, NULL))) {
        emf->base = base;
        d(printf("Setting content base '%s'\n", tmp));
    }
    g_free(basestr);

    if (mime_type != NULL) {
        if (g_ascii_strcasecmp(mime_type, "application/octet-stream") == 0) {
            emf->snoop_mime_type = mime_type = em_utils_snoop_type(part);
            if (mime_type == NULL)
                mime_type = "application/octet-stream";
        }

        handle = em_format_find_handler(emf, mime_type);
        if (handle == NULL)
            handle = em_format_fallback_handler(emf, mime_type);

        if (handle != NULL
            && !em_format_is_attachment(emf, part)) {
            d(printf("running handler for type '%s'\n", mime_type));
            handle->handler(emf, stream, part, handle);
            goto finish;
        }
        d(printf("this type is an attachment? '%s'\n", mime_type));
    } else {
        mime_type = "application/octet-stream";
    }

    ((EMFormatClass *)G_OBJECT_GET_CLASS(emf))->format_attachment(emf, stream, part, mime_type, handle);
finish:
    emf->base = base_save;
    emf->snoop_mime_type = snoop_save;

    if (base)
        camel_url_free(base);
}

void
em_format_part(EMFormat *emf, CamelStream *stream, CamelMimePart *part)
{
    char *mime_type;
    CamelDataWrapper *dw;

    dw = camel_medium_get_content_object((CamelMedium *)part);
    mime_type = camel_data_wrapper_get_mime_type(dw);
    if (mime_type) {
        camel_strdown(mime_type);
        em_format_part_as(emf, stream, part, mime_type);
        g_free(mime_type);
    } else
        em_format_part_as(emf, stream, part, "text/plain");
}

static void
emf_clone_inlines(void *key, void *val, void *data)
{
    struct _EMFormatCache *emfc = val, *new;

    new = emf_insert_cache((EMFormat *)data, emfc->partid);
    new->state = emfc->state;
    if (emfc->valid)
        new->valid = camel_cipher_validity_clone(emfc->valid);
    if (emfc->secured)
        camel_object_ref((new->secured = emfc->secured));
}

static void
emf_format_clone(EMFormat *emf, CamelFolder *folder, const char *uid, CamelMimeMessage *msg, EMFormat *emfsource)
{
    em_format_clear_puri_tree(emf);

    if (emf != emfsource) {
        g_hash_table_foreach(emf->inline_table, emf_free_cache, NULL);
        g_hash_table_destroy(emf->inline_table);
        emf->inline_table = g_hash_table_new(g_str_hash, g_str_equal);
        if (emfsource) {
            struct _EMFormatHeader *h;

            /* We clone the current state here */
            g_hash_table_foreach(emfsource->inline_table, emf_clone_inlines, emf);
            emf->mode = emfsource->mode;
            g_free(emf->charset);
            emf->charset = g_strdup(emfsource->charset);
            g_free (emf->default_charset);
            emf->default_charset = g_strdup (emfsource->default_charset);
            
            em_format_clear_headers(emf);
            for (h = (struct _EMFormatHeader *)emfsource->header_list.head; h->next; h = h->next)
                em_format_add_header(emf, h->name, h->flags);
        }
    }

    /* what a mess */
    if (folder != emf->folder) {
        if (emf->folder)
            camel_object_unref(emf->folder);
        if (folder)
            camel_object_ref(folder);
        emf->folder = folder;
    }

    if (uid != emf->uid) {
        g_free(emf->uid);
        emf->uid = g_strdup(uid);
    }

    if (msg != emf->message) {
        if (emf->message)
            camel_object_unref(emf->message);
        if (msg)
            camel_object_ref(msg);
        emf->message = msg;
    }

    g_string_truncate(emf->part_id, 0);
    if (folder != NULL)
        /* TODO build some string based on the folder name/location? */
        g_string_append_printf(emf->part_id, ".%p", folder);
    if (uid != NULL)
        g_string_append_printf(emf->part_id, ".%s", uid);
}

static void
emf_format_secure(EMFormat *emf, CamelStream *stream, CamelMimePart *part, CamelCipherValidity *valid)
{
    CamelCipherValidity *save = emf->valid_parent;
    int len;

    /* Note that this also requires support from higher up in the class chain
        - validity needs to be cleared when you start output
        - also needs to be cleared (but saved) whenever you start a new message. */

    if (emf->valid == NULL) {
        emf->valid = valid;
    } else {
        e_dlist_addtail(&emf->valid_parent->children, (EDListNode *)valid);
        camel_cipher_validity_envelope(emf->valid_parent, valid);
    }

    emf->valid_parent = valid;

    len = emf->part_id->len;
    g_string_append_printf(emf->part_id, ".secured");
    em_format_part(emf, stream, part);
    g_string_truncate(emf->part_id, len);

    emf->valid_parent = save;
}

static gboolean
emf_busy(EMFormat *emf)
{
    return FALSE;
}

/**
 * em_format_format_clone:
 * @emf: Mail formatter.
 * @folder: Camel Folder.
 * @uid: Uid of message.
 * @msg: Camel Message.
 * @emfsource: Used as a basis for user-altered layout, e.g. inline viewed
 * attachments.
 * 
 * Format a message @msg.  If @emfsource is non NULL, then the status of
 * inlined expansion and so forth is copied direction from @emfsource.
 *
 * By passing the same value for @emf and @emfsource, you can perform
 * a display refresh, or it can be used to generate an identical layout,
 * e.g. to print what the user has shown inline.
 **/
/* e_format_format_clone is a macro */

/**
 * em_format_set_session:
 * @emf: 
 * @s: 
 * 
 * Set the CamelSession to be used for signature verification and decryption
 * purposes.  If this is not set, then signatures cannot be verified or
 * encrypted messages viewed.
 **/
void
em_format_set_session(EMFormat *emf, struct _CamelSession *s)
{
    if (s)
        camel_object_ref(s);
    if (emf->session)
        camel_object_unref(emf->session);
    emf->session = s;
}

/**
 * em_format_set_mode:
 * @emf: 
 * @type: 
 * 
 * Set display mode, EM_FORMAT_SOURCE, EM_FORMAT_ALLHEADERS, or
 * EM_FORMAT_NORMAL.
 **/
void
em_format_set_mode(EMFormat *emf, em_format_mode_t type)
{
    if (emf->mode == type)
        return;

    emf->mode = type;

    /* force redraw if type changed afterwards */
    if (emf->message)
        em_format_redraw(emf);
}

/**
 * em_format_set_charset:
 * @emf: 
 * @charset: 
 * 
 * set override charset on formatter.  message will be redisplayed if
 * required.
 **/
void
em_format_set_charset(EMFormat *emf, const char *charset)
{
    if ((emf->charset && charset && g_ascii_strcasecmp(emf->charset, charset) == 0)
        || (emf->charset == NULL && charset == NULL)
        || (emf->charset == charset))
        return;

    g_free(emf->charset);
    emf->charset = g_strdup(charset);

    if (emf->message)
        em_format_redraw(emf);
}

/**
 * em_format_set_default_charset:
 * @emf: 
 * @charset: 
 * 
 * Set the fallback, default system charset to use when no other charsets
 * are present.  Message will be redisplayed if required (and sometimes redisplayed
 * when it isn't).
 **/
void
em_format_set_default_charset(EMFormat *emf, const char *charset)
{
    if ((emf->default_charset && charset && g_ascii_strcasecmp(emf->default_charset, charset) == 0)
        || (emf->default_charset == NULL && charset == NULL)
        || (emf->default_charset == charset))
        return;

    g_free(emf->default_charset);
    emf->default_charset = g_strdup(charset);

    if (emf->message && emf->charset == NULL)
        em_format_redraw(emf);
}

/**
 * em_format_clear_headers:
 * @emf: 
 * 
 * Clear the list of headers to be displayed.  This will force all headers to
 * be shown.
 **/
void
em_format_clear_headers(EMFormat *emf)
{
    EMFormatHeader *eh;

    while ((eh = (EMFormatHeader *)e_dlist_remhead(&emf->header_list)))
        g_free(eh);
}

/* note: also copied in em-mailer-prefs.c */
static const struct {
    const char *name;
    guint32 flags;
} default_headers[] = {
    { N_("From"), EM_FORMAT_HEADER_BOLD },
    { N_("Reply-To"), EM_FORMAT_HEADER_BOLD },
    { N_("To"), EM_FORMAT_HEADER_BOLD },
    { N_("Cc"), EM_FORMAT_HEADER_BOLD },
    { N_("Bcc"), EM_FORMAT_HEADER_BOLD },
    { N_("Subject"), EM_FORMAT_HEADER_BOLD },
    { N_("Date"), EM_FORMAT_HEADER_BOLD },
    { N_("Newsgroups"), EM_FORMAT_HEADER_BOLD },
};

/**
 * em_format_default_headers:
 * @emf: 
 * 
 * Set the headers to show to the default list.
 *
 * From, Reply-To, To, Cc, Bcc, Subject and Date.
 **/
void
em_format_default_headers(EMFormat *emf)
{
    int i;
    
    em_format_clear_headers(emf);
    for (i=0; i<sizeof(default_headers)/sizeof(default_headers[0]); i++)
        em_format_add_header(emf, default_headers[i].name, default_headers[i].flags);
}

/**
 * em_format_add_header:
 * @emf: 
 * @name: The name of the header, as it will appear during output.
 * @flags: EM_FORMAT_HEAD_* defines to control display attributes.
 * 
 * Add a specific header to show.  If any headers are set, they will
 * be displayed in the order set by this function.  Certain known
 * headers included in this list will be shown using special
 * formatting routines.
 **/
void em_format_add_header(EMFormat *emf, const char *name, guint32 flags)
{
    EMFormatHeader *h;

    h = g_malloc(sizeof(*h) + strlen(name));
    h->flags = flags;
    strcpy(h->name, name);
    e_dlist_addtail(&emf->header_list, (EDListNode *)h);
}

/**
 * em_format_is_attachment:
 * @emf: 
 * @part: Part to check.
 * 
 * Returns true if the part is an attachment.
 *
 * A part is not considered an attachment if it is a
 * multipart, or a text part with no filename.  It is used
 * to determine if an attachment header should be displayed for
 * the part.
 *
 * Content-Disposition is not checked.
 * 
 * Return value: TRUE/FALSE
 **/
int em_format_is_attachment(EMFormat *emf, CamelMimePart *part)
{
    /*CamelContentType *ct = camel_mime_part_get_content_type(part);*/
    CamelDataWrapper *dw = camel_medium_get_content_object((CamelMedium *)part);

    /*printf("checking is attachment %s/%s\n", ct->type, ct->subtype);*/
    return !(camel_content_type_is (dw->mime_type, "multipart", "*")
         || camel_content_type_is(dw->mime_type, "application", "x-pkcs7-mime")
         || camel_content_type_is(dw->mime_type, "application", "pkcs7-mime")
         || camel_content_type_is(dw->mime_type, "application", "x-inlinepgp-signed")
         || camel_content_type_is(dw->mime_type, "application", "x-inlinepgp-encrypted")     
         || (camel_content_type_is (dw->mime_type, "text", "*")
             && camel_mime_part_get_filename(part) == NULL));
}

/**
 * em_format_is_inline:
 * @emf: 
 * @part: 
 * @partid: format->part_id part id of this part.
 * @handle: handler for this part
 * 
 * Returns true if the part should be displayed inline.  Any part with
 * a Content-Disposition of inline, or if the @handle has a default
 * inline set, will be shown inline.
 *
 * :set_inline() called on the same part will override any calculated
 * value.
 * 
 * Return value: 
 **/
int em_format_is_inline(EMFormat *emf, const char *partid, CamelMimePart *part, const EMFormatHandler *handle)
{
    struct _EMFormatCache *emfc;
    const char *tmp;

    if (handle == NULL)
        return FALSE;

    emfc = g_hash_table_lookup(emf->inline_table, partid);
    if (emfc && emfc->state != INLINE_UNSET)
        return emfc->state & 1;

    /* some types need to override the disposition, e.g. application/x-pkcs7-mime */
    if (handle->flags & EM_FORMAT_HANDLER_INLINE_DISPOSITION)
        return TRUE;

    tmp = camel_mime_part_get_disposition(part);
    if (tmp)
        return g_ascii_strcasecmp(tmp, "inline") == 0;

    /* otherwise, use the default for this handler type */
    return (handle->flags & EM_FORMAT_HANDLER_INLINE) != 0;
}

/**
 * em_format_set_inline:
 * @emf: 
 * @partid: id of part
 * @state: 
 * 
 * Force the attachment @part to be expanded or hidden explictly to match
 * @state.  This is used only to record the change for a redraw or
 * cloned layout render and does not force a redraw.
 **/
void em_format_set_inline(EMFormat *emf, const char *partid, int state)
{
    struct _EMFormatCache *emfc;

    emfc = g_hash_table_lookup(emf->inline_table, partid);
    if (emfc == NULL) {
        emfc = emf_insert_cache(emf, partid);
    } else if (emfc->state != INLINE_UNSET && (emfc->state & 1) == state)
        return;

    emfc->state = state?INLINE_ON:INLINE_OFF;

    if (emf->message)
        em_format_redraw(emf);
}

void em_format_format_error(EMFormat *emf, CamelStream *stream, const char *fmt, ...)
{
    va_list ap;
    char *txt;

    va_start(ap, fmt);
    txt = g_strdup_vprintf(fmt, ap);
    ((EMFormatClass *)G_OBJECT_GET_CLASS(emf))->format_error((emf), (stream), (txt));
    g_free(txt);
}

void
em_format_format_secure(EMFormat *emf, struct _CamelStream *stream, struct _CamelMimePart *part, struct _CamelCipherValidity *valid)
{
    ((EMFormatClass *)G_OBJECT_GET_CLASS(emf))->format_secure(emf, stream, part, valid);

    if (emf->valid_parent == NULL && emf->valid != NULL) {
        camel_cipher_validity_free(emf->valid);
        emf->valid = NULL;
    }
}

/* should this be virtual? */
void
em_format_format_content(EMFormat *emf, CamelStream *stream, CamelMimePart *part)
{
    CamelDataWrapper *dw = camel_medium_get_content_object((CamelMedium *)part);

    if (camel_content_type_is (dw->mime_type, "text", "*"))
        em_format_format_text(emf, stream, dw);
    else
        camel_data_wrapper_decode_to_stream(dw, stream);
}

/**
 * em_format_format_content:
 * @emf: 
 * @stream: Where to write the converted text
 * @part: Part whose container is to be formatted
 * 
 * Decode/output a part's content to @stream.
 **/
void
em_format_format_text(EMFormat *emf, CamelStream *stream, CamelDataWrapper *dw)
{
    CamelStreamFilter *filter_stream;
    CamelMimeFilterCharset *filter;
    const char *charset = NULL;
    CamelMimeFilterWindows *windows = NULL;
    
    if (emf->charset) {
        charset = emf->charset;
    } else if (dw->mime_type
           && (charset = camel_content_type_param (dw->mime_type, "charset"))
           && g_ascii_strncasecmp(charset, "iso-8859-", 9) == 0) {
        CamelStream *null;

        /* Since a few Windows mailers like to claim they sent
         * out iso-8859-# encoded text when they really sent
         * out windows-cp125#, do some simple sanity checking
         * before we move on... */

        null = camel_stream_null_new();
        filter_stream = camel_stream_filter_new_with_stream(null);
        camel_object_unref(null);
        
        windows = (CamelMimeFilterWindows *)camel_mime_filter_windows_new(charset);
        camel_stream_filter_add(filter_stream, (CamelMimeFilter *)windows);
        
        camel_data_wrapper_decode_to_stream(dw, (CamelStream *)filter_stream);
        camel_stream_flush((CamelStream *)filter_stream);
        camel_object_unref(filter_stream);
        
        charset = camel_mime_filter_windows_real_charset (windows);
    } else if (charset == NULL) {
        charset = emf->default_charset;
    }
    
    filter_stream = camel_stream_filter_new_with_stream(stream);
    
    if ((filter = camel_mime_filter_charset_new_convert(charset, "UTF-8"))) {
        camel_stream_filter_add(filter_stream, (CamelMimeFilter *) filter);
        camel_object_unref(filter);
    }
    
    camel_data_wrapper_decode_to_stream(dw, (CamelStream *)filter_stream);
    camel_stream_flush((CamelStream *)filter_stream);
    camel_object_unref(filter_stream);

    if (windows)
        camel_object_unref(windows);
}

/**
 * em_format_describe_part:
 * @part: 
 * @mimetype: 
 * 
 * Generate a simple textual description of a part, @mime_type represents the
 * the content.
 * 
 * Return value: 
 **/
char *
em_format_describe_part(CamelMimePart *part, const char *mime_type)
{
    GString *stext;
    const char *text;
    char *out;

    stext = g_string_new("");
    text = gnome_vfs_mime_get_description(mime_type);
    g_string_append_printf(stext, _("%s attachment"), text?text:mime_type);
    if ((text = camel_mime_part_get_filename (part)))
        g_string_append_printf(stext, " (%s)", text);
    if ((text = camel_mime_part_get_description(part)))
        g_string_append_printf(stext, ", \"%s\"", text);

    out = stext->str;
    g_string_free(stext, FALSE);

    return out;
}

/* ********************************************************************** */

#ifdef ENABLE_SMIME
static void
emf_application_xpkcs7mime(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info)
{
    CamelCipherContext *context;
    CamelException *ex;
    extern CamelSession *session;
    CamelMimePart *opart;
    CamelCipherValidity *valid;
    struct _EMFormatCache *emfc;

    /* should this perhaps run off a key of ".secured" ? */
    emfc = g_hash_table_lookup(emf->inline_table, emf->part_id->str);
    if (emfc && emfc->valid) {
        em_format_format_secure(emf, stream, emfc->secured, camel_cipher_validity_clone(emfc->valid));
        return;
    }

    ex = camel_exception_new();

    context = camel_smime_context_new(session);

    opart = camel_mime_part_new();
    valid = camel_cipher_decrypt(context, part, opart, ex);
    if (valid == NULL) {
        em_format_format_error(emf, stream, ex->desc?ex->desc:_("Could not parse S/MIME message: Unknown error"));
        em_format_part_as(emf, stream, part, NULL);
    } else {
        if (emfc == NULL)
            emfc = emf_insert_cache(emf, emf->part_id->str);

        emfc->valid = camel_cipher_validity_clone(valid);
        camel_object_ref((emfc->secured = opart));

        em_format_format_secure(emf, stream, opart, valid);
    }

    camel_object_unref(opart);
    camel_object_unref(context);
    camel_exception_free(ex);
}
#endif

/* RFC 1740 */
static void
emf_multipart_appledouble(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info)
{
    CamelMultipart *mp = (CamelMultipart *)camel_medium_get_content_object((CamelMedium *)part);
    CamelMimePart *mime_part;
    int len;

    if (!CAMEL_IS_MULTIPART(mp)) {
        em_format_format_source(emf, stream, part);
        return;
    }

    mime_part = camel_multipart_get_part(mp, 1);
    if (mime_part) {
        /* try the data fork for something useful, doubtful but who knows */
        len = emf->part_id->len;
        g_string_append_printf(emf->part_id, ".appledouble.1");
        em_format_part(emf, stream, mime_part);
        g_string_truncate(emf->part_id, len);
    } else
        em_format_format_source(emf, stream, part);

}

/* RFC ??? */
static void
emf_multipart_mixed(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info)
{
    CamelMultipart *mp = (CamelMultipart *)camel_medium_get_content_object((CamelMedium *)part);
    int i, nparts, len;

    if (!CAMEL_IS_MULTIPART(mp)) {
        em_format_format_source(emf, stream, part);
        return;
    }

    len = emf->part_id->len;
    nparts = camel_multipart_get_number(mp);    
    for (i = 0; i < nparts; i++) {
        part = camel_multipart_get_part(mp, i);
        g_string_append_printf(emf->part_id, ".mixed.%d", i);
        em_format_part(emf, stream, part);
        g_string_truncate(emf->part_id, len);
    }
}

/* RFC 1740 */
static void
emf_multipart_alternative(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info)
{
    CamelMultipart *mp = (CamelMultipart *)camel_medium_get_content_object((CamelMedium *)part);
    int i, nparts, bestid;
    CamelMimePart *best = NULL;

    if (!CAMEL_IS_MULTIPART(mp)) {
        em_format_format_source(emf, stream, part);
        return;
    }

    /* as per rfc, find the last part we know how to display */
    nparts = camel_multipart_get_number(mp);
    for (i = 0; i < nparts; i++) {
        CamelMimePart *part = camel_multipart_get_part(mp, i);
        CamelContentType *type = camel_mime_part_get_content_type (part);
        char *mime_type = camel_content_type_simple (type);
        
        camel_strdown (mime_type);

        /*if (want_plain && !strcmp (mime_type, "text/plain"))
          return part;*/

        if (em_format_find_handler(emf, mime_type)
            || (best == NULL && em_format_fallback_handler(emf, mime_type))) {
            best = part;
            bestid = i;
        }

        g_free(mime_type);
    }

    if (best) {
        int len = emf->part_id->len;

        g_string_append_printf(emf->part_id, ".alternative.%d", bestid);
        em_format_part(emf, stream, best);
        g_string_truncate(emf->part_id, len);
    } else
        emf_multipart_mixed(emf, stream, part, info);
}

static void
emf_multipart_encrypted(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info)
{
    CamelCipherContext *context;
    CamelException *ex;
    const char *protocol;
    CamelMimePart *opart;
    CamelCipherValidity *valid;
    struct _EMFormatCache *emfc;

    /* should this perhaps run off a key of ".secured" ? */
    emfc = g_hash_table_lookup(emf->inline_table, emf->part_id->str);
    if (emfc && emfc->valid) {
        em_format_format_secure(emf, stream, emfc->secured, camel_cipher_validity_clone(emfc->valid));
        return;
    }

    /* Currently we only handle RFC2015-style PGP encryption. */
    protocol = camel_content_type_param (((CamelDataWrapper *) part)->mime_type, "protocol");
    if (!protocol || g_ascii_strcasecmp (protocol, "application/pgp-encrypted") != 0) {
        em_format_format_error(emf, stream, _("Unsupported encryption type for multipart/encrypted"));
        em_format_part_as(emf, stream, part, "multipart/mixed");
        return;
    }

    ex = camel_exception_new();
    context = camel_gpg_context_new(emf->session);
    opart = camel_mime_part_new();
    valid = camel_cipher_decrypt(context, part, opart, ex);
    if (valid == NULL) {
        em_format_format_error(emf, stream, ex->desc?("Could not parse S/MIME message"):_("Could not parse S/MIME message: Unknown error"));
        if (ex->desc)
            em_format_format_error(emf, stream, ex->desc);
        em_format_part_as(emf, stream, part, "multipart/mixed");
    } else {
        if (emfc == NULL)
            emfc = emf_insert_cache(emf, emf->part_id->str);

        emfc->valid = camel_cipher_validity_clone(valid);
        camel_object_ref((emfc->secured = opart));

        em_format_format_secure(emf, stream, opart, valid);
    }

    /* TODO: Make sure when we finalise this part, it is zero'd out */
    camel_object_unref(opart);
    camel_object_unref(context);
    camel_exception_free(ex);
}

static void
emf_write_related(EMFormat *emf, CamelStream *stream, EMFormatPURI *puri)
{
    em_format_format_content(emf, stream, puri->part);
    camel_stream_close(stream);
}

/* RFC 2387 */
static void
emf_multipart_related(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info)
{
    CamelMultipart *mp = (CamelMultipart *)camel_medium_get_content_object((CamelMedium *)part);
    CamelMimePart *body_part, *display_part = NULL;
    CamelContentType *content_type;
    const char *start;
    int i, nparts, partidlen, displayid = 0;
    char *oldpartid;
    struct _EMFormatPURITree *ptree;
    EMFormatPURI *puri, *purin;

    if (!CAMEL_IS_MULTIPART(mp)) {
        em_format_format_source(emf, stream, part);
        return;
    }

    /* FIXME: put this stuff in a shared function */
    nparts = camel_multipart_get_number(mp);    
    content_type = camel_mime_part_get_content_type(part);
    start = camel_content_type_param (content_type, "start");
    if (start && strlen(start)>2) {
        int len;
        const char *cid;

        /* strip <>'s */
        len = strlen (start) - 2;
        start++;
        
        for (i=0; i<nparts; i++) {
            body_part = camel_multipart_get_part(mp, i);
            cid = camel_mime_part_get_content_id(body_part);
            
            if (cid && !strncmp(cid, start, len) && strlen(cid) == len) {
                display_part = body_part;
                displayid = i;
                break;
            }
        }
    } else {
        display_part = camel_multipart_get_part(mp, 0);
    }
    
    if (display_part == NULL) {
        emf_multipart_mixed(emf, stream, part, info);
        return;
    }
    
    em_format_push_level(emf);

    oldpartid = g_strdup(emf->part_id->str);
    partidlen = emf->part_id->len;

    /* queue up the parts for possible inclusion */
    for (i = 0; i < nparts; i++) {
        body_part = camel_multipart_get_part(mp, i);
        if (body_part != display_part) {
            /* set the partid since add_puri uses it */
            g_string_append_printf(emf->part_id, ".related.%d", i);
            puri = em_format_add_puri(emf, sizeof(EMFormatPURI), NULL, body_part, emf_write_related);
            g_string_truncate(emf->part_id, partidlen);
            d(printf(" part '%s' '%s' added\n", puri->uri?puri->uri:"", puri->cid));
        }
    }
    
    g_string_append_printf(emf->part_id, ".related.%d", displayid);
    em_format_part(emf, stream, display_part);
    g_string_truncate(emf->part_id, partidlen);
    camel_stream_flush(stream);

    ptree = emf->pending_uri_level;
    puri = (EMFormatPURI *)ptree->uri_list.head;
    purin = puri->next;
    while (purin) {
        if (puri->use_count == 0) {
            d(printf("part '%s' '%s' used '%d'\n", puri->uri?puri->uri:"", puri->cid, puri->use_count));
            if (puri->func == emf_write_related) {
                g_string_printf(emf->part_id, "%s", puri->part_id);
                em_format_part(emf, stream, puri->part);
            } else
                d(printf("unreferenced uri generated by format code: %s\n", puri->uri?puri->uri:puri->cid));
        }
        puri = purin;
        purin = purin->next;
    }

    g_string_printf(emf->part_id, "%s", oldpartid);
    g_free(oldpartid);

    em_format_pull_level(emf);
}

static void
emf_multipart_signed(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info)
{
    CamelMimePart *cpart;
    CamelMultipartSigned *mps;
    CamelCipherContext *cipher = NULL;
    struct _EMFormatCache *emfc;

    /* should this perhaps run off a key of ".secured" ? */
    emfc = g_hash_table_lookup(emf->inline_table, emf->part_id->str);
    if (emfc && emfc->valid) {
        em_format_format_secure(emf, stream, emfc->secured, camel_cipher_validity_clone(emfc->valid));
        return;
    }

    mps = (CamelMultipartSigned *)camel_medium_get_content_object((CamelMedium *)part);
    if (!CAMEL_IS_MULTIPART_SIGNED(mps)
        || (cpart = camel_multipart_get_part((CamelMultipart *)mps, CAMEL_MULTIPART_SIGNED_CONTENT)) == NULL) {
        em_format_format_error(emf, stream, _("Could not parse MIME message. Displaying as source."));
        em_format_format_source(emf, stream, part);
        return;
    }

    /* FIXME: Should be done via a plugin interface */
    /* FIXME: duplicated in em-format-html-display.c */
    if (mps->protocol) {
#ifdef ENABLE_SMIME
        if (g_ascii_strcasecmp("application/x-pkcs7-signature", mps->protocol) == 0
            || g_ascii_strcasecmp("application/pkcs7-signature", mps->protocol) == 0)
            cipher = camel_smime_context_new(emf->session);
        else
#endif
            if (g_ascii_strcasecmp("application/pgp-signature", mps->protocol) == 0)
                cipher = camel_gpg_context_new(emf->session);
    }

    if (cipher == NULL) {
        em_format_format_error(emf, stream, _("Unsupported signature format"));
        em_format_part_as(emf, stream, part, "multipart/mixed");
    } else {
        CamelException *ex = camel_exception_new();
        CamelCipherValidity *valid;

        valid = camel_cipher_verify(cipher, part, ex);
        if (valid == NULL) {
            em_format_format_error(emf, stream, ex->desc?_("Error verifying signature"):_("Unknown error verifying signature"));
            if (ex->desc)
                em_format_format_error(emf, stream, ex->desc);
            em_format_part_as(emf, stream, part, "multipart/mixed");
        } else {
            if (emfc == NULL)
                emfc = emf_insert_cache(emf, emf->part_id->str);

            emfc->valid = camel_cipher_validity_clone(valid);
            camel_object_ref((emfc->secured = cpart));

            em_format_format_secure(emf, stream, cpart, valid);
        }

        camel_exception_free(ex);
        camel_object_unref(cipher);
    }
}

static void
emf_message_rfc822(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info)
{
    CamelDataWrapper *dw = camel_medium_get_content_object((CamelMedium *)part);
    const EMFormatHandler *handle;
    int len;

    if (!CAMEL_IS_MIME_MESSAGE(dw)) {
        em_format_format_source(emf, stream, part);
        return;
    }

    len = emf->part_id->len;
    g_string_append_printf(emf->part_id, ".rfc822");

    handle = em_format_find_handler(emf, "x-evolution/message/rfc822");
    if (handle)
        handle->handler(emf, stream, (CamelMimePart *)dw, handle);
    
    g_string_truncate(emf->part_id, len);
}

static void
emf_message_deliverystatus(EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info)
{
    em_format_format_text(emf, stream, camel_medium_get_content_object((CamelMedium *)part));
}

static EMFormatHandler type_builtin_table[] = {
#ifdef ENABLE_SMIME
    { "application/x-pkcs7-mime", (EMFormatFunc)emf_application_xpkcs7mime, EM_FORMAT_HANDLER_INLINE_DISPOSITION },
#endif
    { "multipart/alternative", emf_multipart_alternative },
    { "multipart/appledouble", emf_multipart_appledouble },
    { "multipart/encrypted", emf_multipart_encrypted },
    { "multipart/mixed", emf_multipart_mixed },
    { "multipart/signed", emf_multipart_signed },
    { "multipart/related", emf_multipart_related },
    { "multipart/*", emf_multipart_mixed },
    { "message/rfc822", emf_message_rfc822, EM_FORMAT_HANDLER_INLINE },
    { "message/news", emf_message_rfc822, EM_FORMAT_HANDLER_INLINE },
    { "message/delivery-status", emf_message_deliverystatus },
    { "message/*", emf_message_rfc822, EM_FORMAT_HANDLER_INLINE },

    /* Insert brokenly-named parts here */
#ifdef ENABLE_SMIME
    { "application/pkcs7-mime", (EMFormatFunc)emf_application_xpkcs7mime, EM_FORMAT_HANDLER_INLINE_DISPOSITION },
#endif

};

static void
emf_builtin_init(EMFormatClass *klass)
{
    int i;

    for (i=0;i<sizeof(type_builtin_table)/sizeof(type_builtin_table[0]);i++)
        g_hash_table_insert(klass->type_handlers, type_builtin_table[i].mime_type, &type_builtin_table[i]);
}