sieve-extensions.c

/* Copyright (c) 2002-2018 Pigeonhole authors, see the included COPYING file
 */

#include "lib.h"
#include "str.h"
#include "mempool.h"
#include "hash.h"
#include "array.h"

#include "sieve-common.h"
#include "sieve-error.h"
#include "sieve-settings.h"
#include "sieve-extensions.h"

/*
 * Forward declarations
 */

static void sieve_extension_registry_init(struct sieve_instance *svinst);
static void sieve_extension_registry_deinit(struct sieve_instance *svinst);

static void sieve_capability_registry_init(struct sieve_instance *svinst);
static void sieve_capability_registry_deinit(struct sieve_instance *svinst);

static int
_sieve_extension_register(struct sieve_instance *svinst,
			  const struct sieve_extension_def *extdef,
			  bool load, bool required,
			  struct sieve_extension **ext_r);

/*
 * Instance global context
 */

struct sieve_extension_registry {
	ARRAY(struct sieve_extension *) extensions;
	HASH_TABLE(const char *, struct sieve_extension *) extension_index;
	HASH_TABLE(const char *,
		   struct sieve_capability_registration *) capabilities_index;

	/* Core language 'extensions' */
	const struct sieve_extension *comparator_extension;
	const struct sieve_extension *match_type_extension;
	const struct sieve_extension *address_part_extension;

	/* Preloaded extensions */
	ARRAY(const struct sieve_extension *) preloaded_extensions;
};

/*
 * Pre-loaded 'extensions'
 */

extern const struct sieve_extension_def comparator_extension;
extern const struct sieve_extension_def match_type_extension;
extern const struct sieve_extension_def address_part_extension;

/*
 * Dummy extensions
 */

/* FIXME: This is stupid. Define a comparator-* extension and be done with it */

const struct sieve_extension_def comparator_i_octet_extension = {
	.name = "comparator-i;octet",
};

const struct sieve_extension_def comparator_i_ascii_casemap_extension = {
	.name = "comparator-i;ascii-casemap",
};

/*
 * List of native extensions
 */

/* Dummy extensions */

extern const struct sieve_extension_def comparator_i_octet_extension;
extern const struct sieve_extension_def comparator_i_ascii_casemap_extension;

const struct sieve_extension_def *sieve_dummy_extensions[] = {
	&comparator_i_octet_extension, &comparator_i_ascii_casemap_extension
};

const unsigned int sieve_dummy_extensions_count =
	N_ELEMENTS(sieve_dummy_extensions);

/* Core */

extern const struct sieve_extension_def fileinto_extension;
extern const struct sieve_extension_def reject_extension;
extern const struct sieve_extension_def envelope_extension;
extern const struct sieve_extension_def encoded_character_extension;

extern const struct sieve_extension_def vacation_extension;
extern const struct sieve_extension_def subaddress_extension;
extern const struct sieve_extension_def comparator_i_ascii_numeric_extension;
extern const struct sieve_extension_def relational_extension;
extern const struct sieve_extension_def regex_extension;
extern const struct sieve_extension_def imap4flags_extension;
extern const struct sieve_extension_def copy_extension;
extern const struct sieve_extension_def include_extension;
extern const struct sieve_extension_def body_extension;
extern const struct sieve_extension_def variables_extension;
extern const struct sieve_extension_def enotify_extension;
extern const struct sieve_extension_def environment_extension;
extern const struct sieve_extension_def mailbox_extension;
extern const struct sieve_extension_def date_extension;
extern const struct sieve_extension_def index_extension;
extern const struct sieve_extension_def ihave_extension;
extern const struct sieve_extension_def duplicate_extension;
extern const struct sieve_extension_def mime_extension;
extern const struct sieve_extension_def foreverypart_extension;
extern const struct sieve_extension_def extracttext_extension;
extern const struct sieve_extension_def mboxmetadata_extension;
extern const struct sieve_extension_def servermetadata_extension;

const struct sieve_extension_def *sieve_core_extensions[] = {
	/* Core extensions */
	&fileinto_extension, &reject_extension, &envelope_extension,
	&encoded_character_extension,

	/* 'Plugins' */
	&vacation_extension, &subaddress_extension,
	&comparator_i_ascii_numeric_extension,
	&relational_extension, &regex_extension, &imap4flags_extension,
	&copy_extension, &include_extension, &body_extension,
	&variables_extension, &enotify_extension, &environment_extension,
	&mailbox_extension, &date_extension, &index_extension, &ihave_extension,
	&duplicate_extension, &mime_extension, &foreverypart_extension,
	&extracttext_extension
};

const unsigned int sieve_core_extensions_count =
	N_ELEMENTS(sieve_core_extensions);

/* Extra;
 *   These are not enabled by default, e.g. because explicit configuration is
 *   necessary to make these useful.
 */

extern const struct sieve_extension_def vacation_seconds_extension;
extern const struct sieve_extension_def spamtest_extension;
extern const struct sieve_extension_def spamtestplus_extension;
extern const struct sieve_extension_def virustest_extension;
extern const struct sieve_extension_def editheader_extension;
extern const struct sieve_extension_def special_use_extension;

extern const struct sieve_extension_def vnd_debug_extension;
extern const struct sieve_extension_def vnd_environment_extension;
extern const struct sieve_extension_def vnd_report_extension;

const struct sieve_extension_def *sieve_extra_extensions[] = {
	&vacation_seconds_extension, &spamtest_extension,
	&spamtestplus_extension, &virustest_extension, &editheader_extension,
	&mboxmetadata_extension, &servermetadata_extension,
	&special_use_extension,

	/* vnd.dovecot. */
	&vnd_debug_extension, &vnd_environment_extension, &vnd_report_extension,
};

const unsigned int sieve_extra_extensions_count =
	N_ELEMENTS(sieve_extra_extensions);

/*
 * Unfinished extensions
 */

#ifdef HAVE_SIEVE_UNFINISHED

extern const struct sieve_extension_def ereject_extension;

const struct sieve_extension_def *sieve_unfinished_extensions[] = {
	&ereject_extension
};

const unsigned int sieve_unfinished_extensions_count =
	N_ELEMENTS(sieve_unfinished_extensions);

#endif /* HAVE_SIEVE_UNFINISHED */

/*
 * Extensions init/deinit
 */

int sieve_extensions_init(struct sieve_instance *svinst)
{
	unsigned int i;
	struct sieve_extension_registry *ext_reg =
		p_new(svinst->pool, struct sieve_extension_registry, 1);
	int ret;

	svinst->ext_reg = ext_reg;

	sieve_extension_registry_init(svinst);
	sieve_capability_registry_init(svinst);

	/* Preloaded 'extensions' */
	ret = sieve_extension_register(svinst, &comparator_extension, TRUE,
				       &ext_reg->comparator_extension);
	i_assert(ret == 0);
	ret = sieve_extension_register(svinst, &match_type_extension, TRUE,
				       &ext_reg->match_type_extension);
	i_assert(ret == 0);
	ret = sieve_extension_register(svinst, &address_part_extension, TRUE,
				       &ext_reg->address_part_extension);
	i_assert(ret == 0);

	p_array_init(&ext_reg->preloaded_extensions, svinst->pool, 5);
	array_append(&ext_reg->preloaded_extensions,
		     &ext_reg->comparator_extension, 1);
	array_append(&ext_reg->preloaded_extensions,
		     &ext_reg->match_type_extension, 1);
	array_append(&ext_reg->preloaded_extensions,
		     &ext_reg->address_part_extension, 1);

	/* Pre-load dummy extensions */
	for (i = 0; i < sieve_dummy_extensions_count; i++) {
		struct sieve_extension *ext;

		if (_sieve_extension_register(svinst, sieve_dummy_extensions[i],
					      TRUE, FALSE, &ext) < 0)
			return -1;
		ext->dummy = TRUE;
	}

	/* Pre-load core extensions */
	for (i = 0; i < sieve_core_extensions_count; i++) {
		if (sieve_extension_register(svinst, sieve_core_extensions[i],
					     TRUE, NULL) < 0)
			return -1;
	}

	/* Pre-load extra extensions */
	for (i = 0; i < sieve_extra_extensions_count; i++) {
		if (sieve_extension_register(svinst, sieve_extra_extensions[i],
					     FALSE, NULL) < 0)
			return -1;
	}

#ifdef HAVE_SIEVE_UNFINISHED
	/* Register unfinished extensions */
	for (i = 0; i < sieve_unfinished_extensions_count; i++) {
		if (sieve_extension_register(
			svinst, sieve_unfinished_extensions[i], FALSE,
			NULL) < 0)
			return -1;
	}
#endif

	/* More extensions can be added through plugins */
	return 0;
}

void sieve_extensions_load(struct sieve_instance *svinst)
{
	const char *extensions;

	/* Apply sieve_extensions configuration */
	if ((extensions = sieve_setting_get(
		svinst, "sieve_extensions")) != NULL)
		sieve_extensions_set_string(svinst, extensions, FALSE, FALSE);

	/* Apply sieve_global_extensions configuration */
	if ((extensions = sieve_setting_get(
		svinst, "sieve_global_extensions")) != NULL)
		sieve_extensions_set_string(svinst, extensions, TRUE, FALSE);

	/* Apply sieve_implicit_extensions configuration */
	if ((extensions = sieve_setting_get(
		svinst, "sieve_implicit_extensions")) != NULL)
		sieve_extensions_set_string(svinst, extensions, FALSE, TRUE);
}

void sieve_extensions_deinit(struct sieve_instance *svinst)
{
	sieve_extension_registry_deinit(svinst);
	sieve_capability_registry_deinit(svinst);
}

/*
 * Pre-loaded extensions
 */

const struct sieve_extension *const *
sieve_extensions_get_preloaded(struct sieve_instance *svinst,
			       unsigned int *count_r)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;

	return array_get(&ext_reg->preloaded_extensions, count_r);
}

/*
 * Extension registry
 */

static bool _sieve_extension_load(struct sieve_extension *ext)
{
	/* Call load handler */
	if (ext->def != NULL && ext->def->load != NULL &&
	    !ext->def->load(ext, &ext->context)) {
		e_error(ext->svinst->event,
			"failed to load '%s' extension support.",
			ext->def->name);
		return FALSE;
	}
	return TRUE;
}

static void _sieve_extension_unload(struct sieve_extension *ext)
{
	/* Call unload handler */
	if (ext->def != NULL && ext->def->unload != NULL)
		ext->def->unload(ext);
	ext->context = NULL;
}

static void sieve_extension_registry_init(struct sieve_instance *svinst)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;

	p_array_init(&ext_reg->extensions, svinst->pool, 50);
	hash_table_create(&ext_reg->extension_index, default_pool, 0,
			  str_hash, strcmp);
}

static void sieve_extension_registry_deinit(struct sieve_instance *svinst)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;
	struct sieve_extension *const *exts;
	unsigned int i, ext_count;

	if (!hash_table_is_created(ext_reg->extension_index))
		return;

	exts = array_get_modifiable(&ext_reg->extensions, &ext_count);
	for (i = 0; i < ext_count; i++)
		_sieve_extension_unload(exts[i]);

	hash_table_destroy(&ext_reg->extension_index);
}

bool sieve_extension_reload(const struct sieve_extension *ext)
{
	struct sieve_extension_registry *ext_reg = ext->svinst->ext_reg;
	struct sieve_extension *const *mod_ext;
	int ext_id = ext->id;

	/* Let's not just cast the 'const' away */
	if (ext_id >= 0 && ext_id < (int) array_count(&ext_reg->extensions)) {
		mod_ext = array_idx(&ext_reg->extensions, ext_id);

		return _sieve_extension_load(*mod_ext);
	}
	return FALSE;
}

static struct sieve_extension *
sieve_extension_lookup(struct sieve_instance *svinst, const char *name)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;

	return hash_table_lookup(ext_reg->extension_index, name);
}

static struct sieve_extension *
sieve_extension_alloc(struct sieve_instance *svinst,
		      const struct sieve_extension_def *extdef)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;
	struct sieve_extension *ext, **extr;
	int ext_id;

	ext_id = (int)array_count(&ext_reg->extensions);

	/* Add extension to the registry */
	extr = array_append_space(&ext_reg->extensions);
	*extr = ext = p_new(svinst->pool, struct sieve_extension, 1);
	ext->id = ext_id;
	ext->def = extdef;
	ext->svinst = svinst;
	return ext;
}

static int
_sieve_extension_register(struct sieve_instance *svinst,
			  const struct sieve_extension_def *extdef,
			  bool load, bool required,
			  struct sieve_extension **ext_r)
{
	struct sieve_extension *ext;

	if (ext_r != NULL)
		*ext_r = NULL;
	ext = sieve_extension_lookup(svinst, extdef->name);

	/* Register extension if it is not registered already */
	if (ext == NULL) {
		ext = sieve_extension_alloc(svinst, extdef);
		hash_table_insert(svinst->ext_reg->extension_index,
				  extdef->name, ext);
	} else if (ext->overridden) {
		/* Create a dummy */
		ext = sieve_extension_alloc(svinst, extdef);
	} else {
		/* Re-register it if it were previously unregistered
		 * (not going to happen)
		 */
		i_assert(ext->def == NULL || ext->def == extdef);
		ext->def = extdef;
	}

	/* Enable extension */
	if (load || required) {
		ext->enabled = (ext->enabled || load);

		/* Call load handler if extension was not loaded already */
		if (!ext->loaded) {
			if (!_sieve_extension_load(ext))
				return -1;
		}
		ext->loaded = TRUE;
	}

	ext->required = (ext->required || required);

	if (ext_r != NULL)
		*ext_r = ext;
	return 0;
}

static inline int
_sieve_extension_register_const(struct sieve_instance *svinst,
				const struct sieve_extension_def *extdef,
				bool load, bool required,
				const struct sieve_extension **ext_r)
{
	struct sieve_extension *ext;

	if (_sieve_extension_register(svinst, extdef, load, required,
				      &ext) < 0) {
		if (ext_r != NULL)
			*ext_r = NULL;
		return -1;
	}
	if (ext_r != NULL)
		*ext_r = ext;
	return 0;
}

int sieve_extension_register(struct sieve_instance *svinst,
			     const struct sieve_extension_def *extdef,
			     bool load, const struct sieve_extension **ext_r)
{
	return _sieve_extension_register_const(svinst, extdef, load, FALSE,
					       ext_r);
}

void sieve_extension_unregister(const struct sieve_extension *ext)
{
	if (ext == NULL)
		return;

	struct sieve_extension_registry *ext_reg = ext->svinst->ext_reg;
	struct sieve_extension *const *mod_ext;
	int ext_id = ext->id;

	if (ext_id >= 0 && ext_id < (int) array_count(&ext_reg->extensions)) {
		mod_ext = array_idx(&ext_reg->extensions, ext_id);

		sieve_extension_capabilities_unregister(*mod_ext);
		_sieve_extension_unload(*mod_ext);
		(*mod_ext)->loaded = FALSE;
		(*mod_ext)->enabled = FALSE;
		(*mod_ext)->def = NULL;
	}
}

const struct sieve_extension *
sieve_extension_replace(struct sieve_instance *svinst,
			const struct sieve_extension_def *extdef, bool load)
{
	struct sieve_extension *ext;

	ext = sieve_extension_lookup(svinst, extdef->name);
	if (ext != NULL)
		sieve_extension_unregister(ext);

	const struct sieve_extension *ext_new;

	if (sieve_extension_register(svinst, extdef, load, &ext_new) < 0)
		return NULL;
	return ext_new;
}

const struct sieve_extension *
sieve_extension_require(struct sieve_instance *svinst,
			const struct sieve_extension_def *extdef, bool load)
{
	const struct sieve_extension *ext;

	if (_sieve_extension_register_const(svinst, extdef, load, TRUE,
					    &ext) < 0)
		return NULL;
	return ext;
}

void sieve_extension_override(struct sieve_instance *svinst, const char *name,
			      const struct sieve_extension *ext)
{
	struct sieve_extension_registry *ext_reg = ext->svinst->ext_reg;
	struct sieve_extension *const *mod_ext;
	struct sieve_extension *old_ext;

	old_ext = sieve_extension_lookup(svinst, name);
	if (old_ext == ext)
		return;
	i_assert(old_ext == NULL || !old_ext->overridden);

	i_assert(ext->id >= 0 &&
		 ext->id < (int)array_count(&ext_reg->extensions));
	mod_ext = array_idx(&ext_reg->extensions, ext->id);

	hash_table_update(ext_reg->extension_index, name, *mod_ext);
	if (old_ext != NULL)
		old_ext->overridden = TRUE;
}

unsigned int sieve_extensions_get_count(struct sieve_instance *svinst)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;

	return array_count(&ext_reg->extensions);
}

const struct sieve_extension *const *
sieve_extensions_get_all(struct sieve_instance *svinst, unsigned int *count_r)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;

	return (const struct sieve_extension *const *)
		array_get(&ext_reg->extensions, count_r);
}

const struct sieve_extension *
sieve_extension_get_by_id(struct sieve_instance *svinst, unsigned int ext_id)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;
	struct sieve_extension *const *ext;

	if (ext_id < array_count(&ext_reg->extensions)) {
		ext = array_idx(&ext_reg->extensions, ext_id);

		if ((*ext)->def != NULL &&
		    ((*ext)->enabled || (*ext)->required))
			return *ext;
	}
	return NULL;
}

const struct sieve_extension *
sieve_extension_get_by_name(struct sieve_instance *svinst, const char *name)
{
	const struct sieve_extension *ext;

	if (*name == '@')
		return NULL;
	if (strlen(name) > 128)
		return NULL;

	ext = sieve_extension_lookup(svinst, name);
	if (ext == NULL || ext->def == NULL ||
	    (!ext->enabled && !ext->required))
		return NULL;
	return ext;
}

static inline bool _sieve_extension_listable(const struct sieve_extension *ext)
{
	return (ext->enabled && ext->def != NULL &&
		*(ext->def->name) != '@' && !ext->dummy &&
		!ext->global && !ext->overridden);
}

const char *sieve_extensions_get_string(struct sieve_instance *svinst)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;
	string_t *extstr = t_str_new(256);
	struct sieve_extension *const *exts;
	unsigned int i, ext_count;

	exts = array_get(&ext_reg->extensions, &ext_count);
	if (ext_count > 0) {
		i = 0;

		/* Find first listable extension */
		while (i < ext_count && !_sieve_extension_listable(exts[i]))
			i++;

		if (i < ext_count) {
			/* Add first to string */
			str_append(extstr, exts[i]->def->name);
			i++;

	 		/* Add others */
			for (; i < ext_count; i++) {
				if (_sieve_extension_listable(exts[i])) {
					str_append_c(extstr, ' ');
					str_append(extstr, exts[i]->def->name);
				}
			}
		}
	}
	return str_c(extstr);
}

static void
sieve_extension_set_enabled(struct sieve_extension *ext, bool enabled)
{
	if (enabled) {
		ext->enabled = TRUE;

		if (!ext->loaded)
			(void)_sieve_extension_load(ext);

		ext->loaded = TRUE;
	} else {
		ext->enabled = FALSE;
	}
}

static void
sieve_extension_set_global(struct sieve_extension *ext, bool enabled)
{
	if (enabled) {
		sieve_extension_set_enabled(ext, TRUE);
		ext->global = TRUE;
	} else {
		ext->global = FALSE;
	}
}

static void
sieve_extension_set_implicit(struct sieve_extension *ext, bool enabled)
{
	if (enabled) {
		sieve_extension_set_enabled(ext, TRUE);
		ext->implicit = TRUE;
	} else {
		ext->implicit = FALSE;
	}
}

void sieve_extensions_set_string(struct sieve_instance *svinst,
				 const char *ext_string, bool global,
				 bool implicit)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;
	ARRAY(const struct sieve_extension *) enabled_extensions;
	ARRAY(const struct sieve_extension *) disabled_extensions;
	const struct sieve_extension *const *ext_enabled;
	const struct sieve_extension *const *ext_disabled;
	struct sieve_extension **exts;
	const char **ext_names;
	unsigned int i, ext_count, ena_count, dis_count;
	bool relative = FALSE;

	if (ext_string == NULL) {
		if (global || implicit)
			return;

		/* Enable all */
		exts = array_get_modifiable(&ext_reg->extensions, &ext_count);

		for (i = 0; i < ext_count; i++)
			sieve_extension_set_enabled(exts[i], TRUE);
		return;
	}

	T_BEGIN {
		t_array_init(&enabled_extensions,
			     array_count(&ext_reg->extensions));
		t_array_init(&disabled_extensions,
			     array_count(&ext_reg->extensions));

		ext_names = t_strsplit_spaces(ext_string, " \t");

		while (*ext_names != NULL) {
			const char *name = *ext_names;

			ext_names++;

			if (*name != '\0') {
				const struct sieve_extension *ext;
				char op = '\0'; /* No add/remove operation */

				if (*name == '+' || /* Add to existing config */
				    *name == '-') { /* Remove from existing config */
				 	op = *name++;
				 	relative = TRUE;
				}

				if (*name == '@')
					ext = NULL;
				else {
					ext = hash_table_lookup(ext_reg->extension_index,
								name);
				}

				if (ext == NULL || ext->def == NULL) {
					e_warning(svinst->event,
						  "ignored unknown extension '%s' while configuring "
						  "available extensions", name);
					continue;
				}

				if (op == '-') {
					array_append(&disabled_extensions,
						     &ext, 1);
				} else {
					array_append(&enabled_extensions,
						     &ext, 1);
				}
			}
		}

		exts = array_get_modifiable(&ext_reg->extensions, &ext_count);
		ext_enabled = array_get(&enabled_extensions, &ena_count);
		ext_disabled = array_get(&disabled_extensions, &dis_count);

		/* Set new extension status */

		for (i = 0; i < ext_count; i++) {
			unsigned int j;
			bool enabled = FALSE;

			if (exts[i]->id < 0 || exts[i]->def == NULL ||
			    *(exts[i]->def->name) == '@')
				continue;

			/* If extensions are specified relative to the default
			   set, we first need to check which ones are disabled
			 */
			if (relative) {
				if (global)
					enabled = exts[i]->global;
				else if (implicit)
					enabled = exts[i]->implicit;
				else
					enabled = exts[i]->enabled;

				if (enabled) {
					/* Disable if explicitly disabled */
					for (j = 0; j < dis_count; j++) {
						if (ext_disabled[j]->def == exts[i]->def) {
							enabled = FALSE;
							break;
						}
					}
				}
			}

			/* Enable if listed with '+' or no prefix */
			for (j = 0; j < ena_count; j++) {
				if (ext_enabled[j]->def == exts[i]->def) {
					enabled = TRUE;
					break;
				}
			}

			/* Perform actual activation/deactivation */
			if (global)
				sieve_extension_set_global(exts[i], enabled);
			else if (implicit)
				sieve_extension_set_implicit(exts[i], enabled);
			else
				sieve_extension_set_enabled(exts[i], enabled);
		}
	} T_END;
}

const struct sieve_extension *
sieve_get_match_type_extension(struct sieve_instance *svinst)
{
	return svinst->ext_reg->match_type_extension;
}

const struct sieve_extension *
sieve_get_comparator_extension(struct sieve_instance *svinst)
{
	return svinst->ext_reg->comparator_extension;
}

const struct sieve_extension *
sieve_get_address_part_extension(struct sieve_instance *svinst)
{
	return svinst->ext_reg->address_part_extension;
}

void sieve_enable_debug_extension(struct sieve_instance *svinst)
{
	const struct sieve_extension *ext;
	int ret;

	ret = sieve_extension_register(svinst, &vnd_debug_extension, TRUE,
				       &ext);
	i_assert(ret == 0);
}

/*
 * Extension capabilities
 */

struct sieve_capability_registration {
	const struct sieve_extension *ext;
	const struct sieve_extension_capabilities *capabilities;
};

void sieve_capability_registry_init(struct sieve_instance *svinst)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;

	hash_table_create(&ext_reg->capabilities_index, default_pool, 0,
			  str_hash, strcmp);
}

void sieve_capability_registry_deinit(struct sieve_instance *svinst)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;

	if (!hash_table_is_created(ext_reg->capabilities_index))
		return;

	hash_table_destroy(&svinst->ext_reg->capabilities_index);
}

void sieve_extension_capabilities_register(
	const struct sieve_extension *ext,
	const struct sieve_extension_capabilities *cap)
{
	struct sieve_instance *svinst = ext->svinst;
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;
	struct sieve_capability_registration *reg;

	reg = hash_table_lookup(ext_reg->capabilities_index, cap->name);
	if (reg != NULL) {
		/* Already registered */
		return;
	}

	reg = p_new(svinst->pool, struct sieve_capability_registration, 1);
	reg->ext = ext;
	reg->capabilities = cap;

	hash_table_insert(ext_reg->capabilities_index, cap->name, reg);
}

void sieve_extension_capabilities_unregister(const struct sieve_extension *ext)
{
	struct sieve_extension_registry *ext_reg = ext->svinst->ext_reg;
	struct hash_iterate_context *hictx;
	const char *name;
	struct sieve_capability_registration *reg;

	hictx = hash_table_iterate_init(ext_reg->capabilities_index);
	while (hash_table_iterate(hictx, ext_reg->capabilities_index,
				  &name, &reg)) {
		if (reg->ext == ext)
			hash_table_remove(ext_reg->capabilities_index, name);
	}
	hash_table_iterate_deinit(&hictx);
}

const char *
sieve_extension_capabilities_get_string(struct sieve_instance *svinst,
					const char *cap_name)
{
	struct sieve_extension_registry *ext_reg = svinst->ext_reg;
	const struct sieve_capability_registration *cap_reg =
		hash_table_lookup(ext_reg->capabilities_index, cap_name);
	const struct sieve_extension_capabilities *cap;

	if (cap_reg == NULL || cap_reg->capabilities == NULL)
		return NULL;

	cap = cap_reg->capabilities;
	if (cap->get_string == NULL || !cap_reg->ext->enabled)
		return NULL;

	return cap->get_string(cap_reg->ext);
}