mail-storage-private.h

#ifndef MAIL_STORAGE_PRIVATE_H
#define MAIL_STORAGE_PRIVATE_H

#include "module-context.h"
#include "unichar.h"
#include "file-lock.h"
#include "mail-storage.h"
#include "mail-storage-hooks.h"
#include "mail-storage-settings.h"
#include "mailbox-attribute-private.h"
#include "mail-index-private.h"

/* Default prefix for indexes */
#define MAIL_INDEX_PREFIX "dovecot.index"

/* Block size when read()ing message header. */
#define MAIL_READ_HDR_BLOCK_SIZE (1024*4)
/* Block size when read()ing message (header and) body. */
#define MAIL_READ_FULL_BLOCK_SIZE IO_BLOCK_SIZE

#define MAIL_SHARED_STORAGE_NAME "shared"

struct mail_storage_module_register {
	unsigned int id;
};

struct mail_module_register {
	unsigned int id;
};

struct mail_storage_vfuncs {
	const struct setting_parser_info *(*get_setting_parser_info)(void);

	struct mail_storage *(*alloc)(void);
	int (*create)(struct mail_storage *storage, struct mail_namespace *ns,
		      const char **error_r);
	void (*destroy)(struct mail_storage *storage);
	void (*add_list)(struct mail_storage *storage,
			 struct mailbox_list *list);

	void (*get_list_settings)(const struct mail_namespace *ns,
				  struct mailbox_list_settings *set);
	bool (*autodetect)(const struct mail_namespace *ns,
			   struct mailbox_list_settings *set);

	struct mailbox *(*mailbox_alloc)(struct mail_storage *storage,
					 struct mailbox_list *list,
					 const char *vname,
					 enum mailbox_flags flags);
	int (*purge)(struct mail_storage *storage);
	/* Called when mailbox list index corruption has been detected.
	   The callback should add any missing mailboxes to the list index.
	   Returns 0 on success, -1 on temporary failure that didn't properly
	   fix the index. */
	int (*list_index_corrupted)(struct mail_storage *storage);
};

union mail_storage_module_context {
	struct mail_storage_vfuncs super;
	struct mail_storage_module_register *reg;
};

enum mail_storage_class_flags {
	/* mailboxes are files, not directories */
	MAIL_STORAGE_CLASS_FLAG_MAILBOX_IS_FILE	= 0x01,
	/* root_dir points to a unique directory */
	MAIL_STORAGE_CLASS_FLAG_UNIQUE_ROOT	= 0x02,
	/* mailbox_open_stream() is supported */
	MAIL_STORAGE_CLASS_FLAG_OPEN_STREAMS	= 0x04,
	/* never use quota for this storage (e.g. virtual mailboxes) */
	MAIL_STORAGE_CLASS_FLAG_NOQUOTA		= 0x08,
	/* Storage doesn't need a mail root directory */
	MAIL_STORAGE_CLASS_FLAG_NO_ROOT		= 0x10,
	/* Storage uses one file per message */
	MAIL_STORAGE_CLASS_FLAG_FILE_PER_MSG	= 0x20,
	/* Messages have GUIDs (always set mailbox_status.have_guids=TRUE) */
	MAIL_STORAGE_CLASS_FLAG_HAVE_MAIL_GUIDS	= 0x40,
	/* mailbox_save_set_guid() works (always set
	   mailbox_status.have_save_guids=TRUE) */
	MAIL_STORAGE_CLASS_FLAG_HAVE_MAIL_SAVE_GUIDS	= 0x80,
	/* message content can be unstructured binary data
	   (e.g. zlib plugin is allowed to compress/decompress mails) */
	MAIL_STORAGE_CLASS_FLAG_BINARY_DATA	= 0x100,
	/* Message GUIDs can only be 128bit (always set
	   mailbox_status.have_only_guid128) */
	MAIL_STORAGE_CLASS_FLAG_HAVE_MAIL_GUID128 = 0x200,
	/* Storage deletes all files internally - mailbox list's
	   delete_mailbox() shouldn't delete anything itself. */
	MAIL_STORAGE_CLASS_FLAG_NO_LIST_DELETES	= 0x400,
	/* Storage supports stubs (used for caching purposes). */
	MAIL_STORAGE_CLASS_FLAG_STUBS = 0x800,
};

struct mail_binary_cache {
	struct timeout *to;
	struct mailbox *box;
	uint32_t uid;

	uoff_t orig_physical_pos;
	bool include_hdr;
	struct istream *input;
	uoff_t size;
};

struct mail_storage_error {
	char *error_string;
	enum mail_error error;
	char *last_internal_error;
	bool last_error_is_internal;
};

struct mail_storage {
	const char *name;
	enum mail_storage_class_flags class_flags;
	/* Fields that the storage backend can get by other means than parsing
	   the message header/body. For example the imapc backend can lookup
	   MAIL_FETCH_IMAP_BODYSTRUCTURE from the remote server. Adding fields
	   here avoids adding them to index_mail_data.access_part. */
	enum mail_fetch_field nonbody_access_fields;

        struct mail_storage_vfuncs v, *vlast;

/* private: */
	pool_t pool;
	struct mail_storage *prev, *next;
	/* counting number of times mail_storage_create() has returned this
	   same storage. */
	int refcount;
	/* counting number of objects (e.g. mailbox) that have a pointer
	   to this storage. */
	int obj_refcount;
	/* Linked list of all mailboxes in the storage */
	struct mailbox *mailboxes;
	/* A "root dir" to enable storage sharing.  It is only ever used for
	 * uniqueness checking (via strcmp) and never used as a path. */
	const char *unique_root_dir;

	/* Last error set in mail_storage_set_critical(). */
	char *last_internal_error;

	char *error_string;
	enum mail_error error;
	ARRAY(struct mail_storage_error) error_stack;

        const struct mail_storage *storage_class;
	struct mail_user *user;
	const char *temp_path_prefix;
	const struct mail_storage_settings *set;

	enum mail_storage_flags flags;

	struct mail_storage_callbacks callbacks;
	void *callback_context;

	struct mail_binary_cache binary_cache;
	/* Filled lazily by mailbox_attribute_*() when accessing shared
	   attributes. */
	struct dict *_shared_attr_dict;

	/* Module-specific contexts. See mail_storage_module_id. */
	ARRAY(union mail_storage_module_context *) module_contexts;

	/* Failed to create shared attribute dict, don't try again */
	bool shared_attr_dict_failed:1;
	bool last_error_is_internal:1;
};

struct mail_attachment_part {
	struct message_part *part;
	const char *content_type, *content_disposition;
};

struct virtual_mailbox_vfuncs {
	/* convert backend UIDs to virtual UIDs. if some backend UID doesn't
	   exist in mailbox, it's simply ignored */
	void (*get_virtual_uids)(struct mailbox *box,
				 struct mailbox *backend_mailbox,
				 const ARRAY_TYPE(seq_range) *backend_uids,
				 ARRAY_TYPE(seq_range) *virtual_uids_r);
	/* like get_virtual_uids(), but if a backend UID doesn't exist,
	   convert it to 0. */
	void (*get_virtual_uid_map)(struct mailbox *box,
				    struct mailbox *backend_mailbox,
				    const ARRAY_TYPE(seq_range) *backend_uids,
				    ARRAY_TYPE(uint32_t) *virtual_uids_r);
	void (*get_virtual_backend_boxes)(struct mailbox *box,
					  ARRAY_TYPE(mailboxes) *mailboxes,
					  bool only_with_msgs);
};

struct mailbox_vfuncs {
	bool (*is_readonly)(struct mailbox *box);

	int (*enable)(struct mailbox *box, enum mailbox_feature features);
	int (*exists)(struct mailbox *box, bool auto_boxes,
		      enum mailbox_existence *existence_r);
	int (*open)(struct mailbox *box);
	void (*close)(struct mailbox *box);
	void (*free)(struct mailbox *box);

	int (*create_box)(struct mailbox *box,
			  const struct mailbox_update *update, bool directory);
	int (*update_box)(struct mailbox *box,
			  const struct mailbox_update *update);
	int (*delete_box)(struct mailbox *box);
	int (*rename_box)(struct mailbox *src, struct mailbox *dest);

	int (*get_status)(struct mailbox *box, enum mailbox_status_items items,
			  struct mailbox_status *status_r);
	int (*get_metadata)(struct mailbox *box,
			    enum mailbox_metadata_items items,
			    struct mailbox_metadata *metadata_r);
	int (*set_subscribed)(struct mailbox *box, bool set);

	int (*attribute_set)(struct mailbox_transaction_context *t,
			     enum mail_attribute_type type, const char *key,
			     const struct mail_attribute_value *value);
	int (*attribute_get)(struct mailbox *box,
			     enum mail_attribute_type type, const char *key,
			     struct mail_attribute_value *value_r);
	struct mailbox_attribute_iter *
		(*attribute_iter_init)(struct mailbox *box,
				       enum mail_attribute_type type,
				       const char *prefix);
	const char *(*attribute_iter_next)(struct mailbox_attribute_iter *iter);
	int (*attribute_iter_deinit)(struct mailbox_attribute_iter *iter);

	/* Lookup sync extension record and figure out if it mailbox has
	   changed since. Returns 1 = yes, 0 = no, -1 = error. if quick==TRUE,
	   return 1 if it's too costly to find out exactly. */
	int (*list_index_has_changed)(struct mailbox *box,
				      struct mail_index_view *list_view,
				      uint32_t seq, bool quick);
	/* Update the sync extension record. */
	void (*list_index_update_sync)(struct mailbox *box,
				       struct mail_index_transaction *trans,
				       uint32_t seq);

	struct mailbox_sync_context *
		(*sync_init)(struct mailbox *box,
			     enum mailbox_sync_flags flags);
	bool (*sync_next)(struct mailbox_sync_context *ctx,
			  struct mailbox_sync_rec *sync_rec_r);
	int (*sync_deinit)(struct mailbox_sync_context *ctx,
			   struct mailbox_sync_status *status_r);

	/* Called once for each expunge. Called one or more times for
	   flag/keyword changes. Once the sync is finished, called with
	   uid=0 and sync_type=0. */
	void (*sync_notify)(struct mailbox *box, uint32_t uid,
			    enum mailbox_sync_type sync_type);

	void (*notify_changes)(struct mailbox *box);

	struct mailbox_transaction_context *
		(*transaction_begin)(struct mailbox *box,
				     enum mailbox_transaction_flags flags);
	int (*transaction_commit)(struct mailbox_transaction_context *t,
				  struct mail_transaction_commit_changes *changes_r);
	void (*transaction_rollback)(struct mailbox_transaction_context *t);

	enum mail_flags (*get_private_flags_mask)(struct mailbox *box);

	struct mail *
		(*mail_alloc)(struct mailbox_transaction_context *t,
			      enum mail_fetch_field wanted_fields,
			      struct mailbox_header_lookup_ctx *wanted_headers);

	struct mail_search_context *
	(*search_init)(struct mailbox_transaction_context *t,
		       struct mail_search_args *args,
		       const enum mail_sort_type *sort_program,
		       enum mail_fetch_field wanted_fields,
		       struct mailbox_header_lookup_ctx *wanted_headers);
	int (*search_deinit)(struct mail_search_context *ctx);
	bool (*search_next_nonblock)(struct mail_search_context *ctx,
				     struct mail **mail_r, bool *tryagain_r);
	/* Internal search function which updates ctx->seq */
	bool (*search_next_update_seq)(struct mail_search_context *ctx);

	struct mail_save_context *
		(*save_alloc)(struct mailbox_transaction_context *t);
	int (*save_begin)(struct mail_save_context *ctx, struct istream *input);
	int (*save_continue)(struct mail_save_context *ctx);
	int (*save_finish)(struct mail_save_context *ctx);
	void (*save_cancel)(struct mail_save_context *ctx);
	int (*copy)(struct mail_save_context *ctx, struct mail *mail);

	/* Called during transaction commit/rollback if saving was done */
	int (*transaction_save_commit_pre)(struct mail_save_context *save_ctx);
	void (*transaction_save_commit_post)
		(struct mail_save_context *save_ctx,
		 struct mail_index_transaction_commit_result *result_r);
	void (*transaction_save_rollback)(struct mail_save_context *save_ctx);

	bool (*is_inconsistent)(struct mailbox *box);
};

union mailbox_module_context {
        struct mailbox_vfuncs super;
	struct mail_storage_module_register *reg;
};

struct mail_msgpart_partial_cache {
	uint32_t uid;
	uoff_t physical_start;
	uoff_t physical_pos, virtual_pos;
};

struct mailbox_index_vsize {
	uint64_t vsize;
	uint32_t highest_uid;
	uint32_t message_count;
};

struct mailbox_index_pop3_uidl {
	uint32_t max_uid_with_pop3_uidl;
};

struct mailbox_index_first_saved {
	uint32_t uid;
	uint32_t timestamp;
};

struct mailbox {
	const char *name;
	/* mailbox's virtual name (from mail_namespace_get_vname()) */
	const char *vname;
	struct mail_storage *storage;
	struct mailbox_list *list;

	struct mailbox_vfuncs v, *vlast;
	/* virtual mailboxes: */
	const struct virtual_mailbox_vfuncs *virtual_vfuncs;
/* private: */
	pool_t pool, metadata_pool;
	/* Linked list of all mailboxes in this storage */
	struct mailbox *prev, *next;

	/* these won't be set until mailbox is opened: */
	struct mail_index *index;
	struct mail_index_view *view;
	struct mail_cache *cache;
	/* Private per-user index/view for shared mailboxes. These are synced
	   against the primary index and used to store per-user flags.
	   These are non-NULL only when mailbox has per-user flags. */
	struct mail_index *index_pvt;
	struct mail_index_view *view_pvt;
	/* Filled lazily by mailbox_get_permissions() */
	struct mailbox_permissions _perm;
	/* Filled lazily when mailbox is opened, use mailbox_get_path()
	   to access it */
	const char *_path;
	/* Filled lazily when mailbox is opened, use mailbox_get_index_path()
	   to access it */
	const char *_index_path;
	/* Reason for why mailbox is being accessed or NULL if unknown. */
	const char *reason;

	/* default vfuncs for new struct mails. */
	const struct mail_vfuncs *mail_vfuncs;
	/* Mailbox settings, or NULL if defaults */
	const struct mailbox_settings *set;

	/* If non-zero, fail mailbox_open() with this error. mailbox_alloc()
	   can set this to force open to fail. */
	enum mail_error open_error;

	struct istream *input;
	const char *index_prefix;
	enum mailbox_flags flags;
	unsigned int transaction_count;
	enum mailbox_feature enabled_features;
	struct mail_msgpart_partial_cache partial_cache;
	uint32_t vsize_hdr_ext_id;
	uint32_t pop3_uidl_hdr_ext_id;
	uint32_t box_name_hdr_ext_id;
	uint32_t box_last_rename_stamp_ext_id;
	uint32_t mail_vsize_ext_id;

	/* MAIL_RECENT flags handling */
	ARRAY_TYPE(seq_range) recent_flags;
	uint32_t recent_flags_prev_uid;
	uint32_t recent_flags_count;

	struct mail_index_view *tmp_sync_view;

	/* Mailbox notification settings: */
	mailbox_notify_callback_t *notify_callback;
	void *notify_context;
	struct timeout *to_notify, *to_notify_delay;
	struct mailbox_notify_file *notify_files;

	/* Increased by one for each new struct mailbox. */
	unsigned int generation_sequence;

	/* Saved search results */
	ARRAY(struct mail_search_result *) search_results;

	/* Module-specific contexts. See mail_storage_module_id. */
	ARRAY(union mailbox_module_context *) module_contexts;

	/* When FAST open flag is used, the mailbox isn't actually opened until
	   it's synced for the first time. */
	bool opened:1;
	/* Mailbox was deleted while we had it open. */
	bool mailbox_deleted:1;
	/* Mailbox is being created */
	bool creating:1;
	/* Mailbox is being deleted */
	bool deleting:1;
	/* Mailbox is being undeleted */
	bool mailbox_undeleting:1;
	/* Don't use MAIL_INDEX_SYNC_FLAG_DELETING_INDEX for sync flag */
	bool delete_sync_check:1;
	/* Delete mailbox only if it's empty */
	bool deleting_must_be_empty:1;
	/* The backend wants to skip checking if there are 0 messages before
	   calling mailbox_list.delete_mailbox() */
	bool delete_skip_empty_check:1;
	/* Mailbox was already marked as deleted within this allocation. */
	bool marked_deleted:1;
	/* TRUE if this is an INBOX for this user */
	bool inbox_user:1;
	/* TRUE if this is an INBOX for this namespace (user or shared) */
	bool inbox_any:1;
	/* When copying to this mailbox, require that mailbox_copy() uses
	   mailbox_save_*() to actually save a new physical copy rather than
	   simply incrementing a reference count (e.g. via hard link) */
	bool disable_reflink_copy_to:1;
	/* Don't allow creating any new keywords */
	bool disallow_new_keywords:1;
	/* Mailbox has been synced at least once */
	bool synced:1;
	/* Updating cache file is disabled */
	bool mail_cache_disabled:1;
	/* Update first_saved field to mailbox list index. */
	bool update_first_saved:1;
	/* mailbox_verify_create_name() only checks for mailbox_verify_name() */
	bool skip_create_name_restrictions:1;
	/* Using LAYOUT=index and mailbox is being opened with a corrupted
	   mailbox name. Try to revert to the previously known good name. */
	bool corrupted_mailbox_name:1;
};

struct mail_vfuncs {
	void (*close)(struct mail *mail);
	void (*free)(struct mail *mail);
	void (*set_seq)(struct mail *mail, uint32_t seq, bool saving);
	bool (*set_uid)(struct mail *mail, uint32_t uid);
	void (*set_uid_cache_updates)(struct mail *mail, bool set);
	bool (*prefetch)(struct mail *mail);
	void (*precache)(struct mail *mail);
	void (*add_temp_wanted_fields)(struct mail *mail,
				       enum mail_fetch_field fields,
				       struct mailbox_header_lookup_ctx *headers);

	enum mail_flags (*get_flags)(struct mail *mail);
	const char *const *(*get_keywords)(struct mail *mail);
	const ARRAY_TYPE(keyword_indexes) *
		(*get_keyword_indexes)(struct mail *mail);
	uint64_t (*get_modseq)(struct mail *mail);
	uint64_t (*get_pvt_modseq)(struct mail *mail);

	int (*get_parts)(struct mail *mail,
			 struct message_part **parts_r);
	int (*get_date)(struct mail *mail, time_t *date_r, int *timezone_r);
	int (*get_received_date)(struct mail *mail, time_t *date_r);
	int (*get_save_date)(struct mail *mail, time_t *date_r);
	int (*get_virtual_size)(struct mail *mail, uoff_t *size_r);
	int (*get_physical_size)(struct mail *mail, uoff_t *size_r);

	int (*get_first_header)(struct mail *mail, const char *field,
				bool decode_to_utf8, const char **value_r);
	int (*get_headers)(struct mail *mail, const char *field,
			   bool decode_to_utf8, const char *const **value_r);
	int (*get_header_stream)(struct mail *mail,
				 struct mailbox_header_lookup_ctx *headers,
				 struct istream **stream_r);
	int (*get_stream)(struct mail *mail, bool get_body,
			  struct message_size *hdr_size,
			  struct message_size *body_size,
			  struct istream **stream_r);
	int (*get_binary_stream)(struct mail *mail,
				 const struct message_part *part,
				 bool include_hdr, uoff_t *size_r,
				 unsigned int *lines_r, bool *binary_r,
				 struct istream **stream_r);

	int (*get_special)(struct mail *mail, enum mail_fetch_field field,
			   const char **value_r);
	int (*get_backend_mail)(struct mail *mail, struct mail **real_mail_r);

	void (*update_flags)(struct mail *mail, enum modify_type modify_type,
			     enum mail_flags flags);
	void (*update_keywords)(struct mail *mail, enum modify_type modify_type,
				struct mail_keywords *keywords);
	void (*update_modseq)(struct mail *mail, uint64_t min_modseq);
	void (*update_pvt_modseq)(struct mail *mail, uint64_t min_pvt_modseq);
	void (*update_pop3_uidl)(struct mail *mail, const char *uidl);
	void (*expunge)(struct mail *mail);
	void (*set_cache_corrupted)(struct mail *mail,
				    enum mail_fetch_field field,
				    const char *reason);
	int (*istream_opened)(struct mail *mail, struct istream **input);
};

union mail_module_context {
	struct mail_vfuncs super;
	struct mail_module_register *reg;
};

struct mail_private {
	struct mail mail;
	struct mail_vfuncs v, *vlast;
	/* normally NULL, but in case this is a "backend mail" for a mail
	   created by virtual storage, this points back to the original virtual
	   mail. at least mailbox_copy() bypasses the virtual storage, so this
	   allows mail_log plugin to log the copy operation using the original
	   mailbox name. */
	struct mail *vmail;

	uint32_t seq_pvt;

	/* initial wanted fields/headers, set by mail_alloc(): */
	enum mail_fetch_field wanted_fields;
	struct mailbox_header_lookup_ctx *wanted_headers;

	pool_t pool, data_pool;
	ARRAY(union mail_module_context *) module_contexts;

	const char *get_stream_reason;

	bool autoexpunged:1;
};

struct mailbox_list_context {
	struct mail_storage *storage;
	enum mailbox_list_flags flags;
	bool failed;
};

union mailbox_transaction_module_context {
	struct mail_storage_module_register *reg;
};

struct mailbox_transaction_stats {
	unsigned long open_lookup_count;
	unsigned long stat_lookup_count;
	unsigned long fstat_lookup_count;
	/* number of files we've opened and read */
	unsigned long files_read_count;
	/* number of bytes we've had to read from files */
	unsigned long long files_read_bytes;
	/* number of cache lookup hits */
	unsigned long cache_hit_count;
};

struct mail_save_private_changes {
	/* first saved mail is 0, second is 1, etc. we'll map these to UIDs
	   using struct mail_transaction_commit_changes. */
	unsigned int mailnum;
	enum mail_flags flags;
};

struct mailbox_transaction_context {
	struct mailbox *box;
	enum mailbox_transaction_flags flags;
	char *reason;

	union mail_index_transaction_module_context module_ctx;
	struct mail_index_transaction_vfuncs super;
	int mail_ref_count;

	struct mail_index_transaction *itrans;
	struct dict_transaction_context *attr_pvt_trans, *attr_shared_trans;
	/* view contains all changes done within this transaction */
	struct mail_index_view *view;

	/* for private index updates: */
	struct mail_index_transaction *itrans_pvt;
	struct mail_index_view *view_pvt;

	struct mail_cache_view *cache_view;
	struct mail_cache_transaction_ctx *cache_trans;

	struct mail_transaction_commit_changes *changes;
	ARRAY(union mailbox_transaction_module_context *) module_contexts;

	uint32_t prev_pop3_uidl_tracking_seq;
	uint32_t highest_pop3_uidl_uid;

	struct mail_save_context *save_ctx;
	/* number of mails saved/copied within this transaction. */
	unsigned int save_count;
	/* List of private flags added with save/copy. These are added to the
	   private index after committing the mails to the shared index. */
	ARRAY(struct mail_save_private_changes) pvt_saves;

	/* these statistics are never reset by mail-storage API: */
	struct mailbox_transaction_stats stats;
	/* Set to TRUE to update stats_* fields */
	bool stats_track:1;
	/* We've done some non-transactional (e.g. dovecot-uidlist updates) */
	bool nontransactional_changes:1;
};

union mail_search_module_context {
	struct mail_storage_module_register *reg;
};

struct mail_search_context {
	struct mailbox_transaction_context *transaction;

	struct mail_search_args *args;
	struct mail_search_sort_program *sort_program;
	enum mail_fetch_field wanted_fields;
	struct mailbox_header_lookup_ctx *wanted_headers;
	normalizer_func_t *normalizer;

	/* if non-NULL, specifies that a search resulting is being updated.
	   this can be used as a search optimization: if searched message
	   already exists in search result, it's not necessary to check if
	   static data matches. */
	struct mail_search_result *update_result;
	/* add matches to these search results */
	ARRAY(struct mail_search_result *) results;

	uint32_t seq;
	uint32_t progress_cur, progress_max;

	ARRAY(union mail_search_module_context *) module_contexts;

	bool seen_lost_data:1;
	bool progress_hidden:1;
};

struct mail_save_data {
	enum mail_flags flags;
	enum mail_flags pvt_flags;
	struct mail_keywords *keywords;
	uint64_t min_modseq;

	time_t received_date, save_date;
	int received_tz_offset;

	uint32_t uid, stub_seq;
	char *guid, *pop3_uidl, *from_envelope;
	unsigned int pop3_order;

	struct ostream *output;
	struct mail_save_attachment *attach;
};

struct mail_save_context {
	struct mailbox_transaction_context *transaction;
	struct mail *dest_mail;
	/* Set during mailbox_copy(). This is useful when copying is
	   implemented via save, and the save_*() methods want to access the
	   source mail. */
	struct mail *copy_src_mail;

	/* data that changes for each saved mail */
	struct mail_save_data data;

	/* returns TRUE if message part is an attachment. */
	bool (*part_is_attachment)(struct mail_save_context *ctx,
				   const struct mail_attachment_part *part);

	/* mailbox_save_alloc() called, but finish/cancel not.
	   the same context is usually returned by the backends for reuse. */
	bool unfinished:1;
	/* mailbox_save_finish() or mailbox_copy() is being called. */
	bool finishing:1;
	/* mail was copied or moved using saving (requires:
	   copying_or_moving==TRUE). */
	bool copying_via_save:1;
	/* mail is being saved, not copied. However, this is set also with
	   mailbox_save_using_mail() and then copying_or_moving==TRUE. */
	bool saving:1;
	/* mail is being moved - ignore quota (requires:
	   copying_or_moving==TRUE && saving==FALSE). */
	bool moving:1;
	/* mail is being copied or moved. However, this is set also with
	   mailbox_save_using_mail() and then saving==TRUE. */
	bool copying_or_moving:1;
	/* dest_mail was set via mailbox_save_set_dest_mail() */
	bool dest_mail_external:1;
};

struct mailbox_sync_context {
	struct mailbox *box;
	enum mailbox_sync_flags flags;
	bool open_failed;
};

struct mailbox_header_lookup_ctx {
	struct mailbox *box;
	pool_t pool;
	int refcount;

	unsigned int count;
	const char *const *name;
	unsigned int *idx;
};

/* Modules should use do "my_id = mail_storage_module_id++" and
   use objects' module_contexts[id] for their own purposes. */
extern struct mail_storage_module_register mail_storage_module_register;

/* Storage's module_id for mail_index. */
extern struct mail_module_register mail_module_register;

#define MAIL_STORAGE_CONTEXT(obj) \
	MODULE_CONTEXT(obj, mail_storage_mail_index_module)
extern MODULE_CONTEXT_DEFINE(mail_storage_mail_index_module,
			     &mail_index_module_register);

void mail_storage_obj_ref(struct mail_storage *storage);
void mail_storage_obj_unref(struct mail_storage *storage);

/* Set error message in storage. Critical errors are logged with i_error(),
   but user sees only "internal error" message. */
void mail_storage_clear_error(struct mail_storage *storage);
void mail_storage_set_error(struct mail_storage *storage,
			    enum mail_error error, const char *string);
void mail_storage_set_critical(struct mail_storage *storage,
			       const char *fmt, ...) ATTR_FORMAT(2, 3);
void mail_storage_set_internal_error(struct mail_storage *storage);
void mailbox_set_index_error(struct mailbox *box);
bool mail_storage_set_error_from_errno(struct mail_storage *storage);
void mail_storage_copy_list_error(struct mail_storage *storage,
				  struct mailbox_list *list);
void mail_storage_copy_error(struct mail_storage *dest,
			     struct mail_storage *src);
/* set record in mail cache corrupted */
void mail_set_mail_cache_corrupted(struct mail *mail, const char *fmt, ...)
	ATTR_FORMAT(2, 3);

/* Indicate mail being expunged by autoexpunge */
void mail_autoexpunge(struct mail *mail);

/* Returns TRUE if everything should already be in memory after this call
   or if prefetching is not supported, i.e. the caller shouldn't do more
   prefetching before this message is handled. */
bool mail_prefetch(struct mail *mail);
void mail_set_aborted(struct mail *mail);
void mail_set_expunged(struct mail *mail);
void mail_set_seq_saving(struct mail *mail, uint32_t seq);
void mailbox_set_deleted(struct mailbox *box);
int mailbox_mark_index_deleted(struct mailbox *box, bool del);
/* Easy wrapper for getting mailbox's MAILBOX_LIST_PATH_TYPE_MAILBOX.
   The mailbox must already be opened and the caller must know that the
   storage has mailbox files (i.e. NULL/empty path is never returned). */
const char *mailbox_get_path(struct mailbox *box) ATTR_PURE;
/* Similar to mailbox_get_path() but for MAILBOX_LIST_PATH_TYPE_INDEX. */
const char *mailbox_get_index_path(struct mailbox *box) ATTR_PURE;
/* Wrapper to mailbox_list_get_path() */
int mailbox_get_path_to(struct mailbox *box, enum mailbox_list_path_type type,
			const char **path_r);
/* Get mailbox permissions. */
const struct mailbox_permissions *mailbox_get_permissions(struct mailbox *box);
/* Force permissions to be refreshed on next lookup */
void mailbox_refresh_permissions(struct mailbox *box);

/* Open private index files for mailbox. Returns 1 if opened, 0 if there
   are no private indexes (or flags) in this mailbox, -1 if error. */
int mailbox_open_index_pvt(struct mailbox *box);
/* Create path's directory with proper permissions. The root directory is also
   created if necessary. Returns 1 if created, 0 if it already existed,
   -1 if error. */
int mailbox_mkdir(struct mailbox *box, const char *path,
		  enum mailbox_list_path_type type);
/* Create a non-mailbox type directory for mailbox if it's missing (e.g. index).
   Optimized for case where the directory usually exists. */
int mailbox_create_missing_dir(struct mailbox *box,
			       enum mailbox_list_path_type type);
/* Returns TRUE if mailbox is autocreated. */
bool mailbox_is_autocreated(struct mailbox *box);

/* Returns -1 if error, 0 if failed with EEXIST, 1 if ok */
int mailbox_create_fd(struct mailbox *box, const char *path, int flags,
		      int *fd_r);
/* Create a lock file to the mailbox with the given filename. If it succeeds,
   returns 1 and lock_r, which needs to be freed once finished with the lock.
   If lock_secs is reached, returns 0 and error_r. Returns -1 and sets error_r
   on other errors. */
int mailbox_lock_file_create(struct mailbox *box, const char *lock_fname,
			     unsigned int lock_secs, struct file_lock **lock_r,
			     const char **error_r);
unsigned int mail_storage_get_lock_timeout(struct mail_storage *storage,
					   unsigned int secs);
void mail_storage_free_binary_cache(struct mail_storage *storage);

enum mail_index_open_flags
mail_storage_settings_to_index_flags(const struct mail_storage_settings *set);
void mailbox_save_context_deinit(struct mail_save_context *ctx);

#endif