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#ifndef DBFS_DBFS_H

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#define DBFS_DBFS_H

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#include <sys/stat.h>

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#include <errno.h>

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#include <event2/event.h>

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#include "ops.h"

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#include "../evfuse.h"

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#include "../evsql.h"

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#include "../lib/error.h"

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/*

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 * Structs and functions shared between all dbfs components

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 */

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struct dbfs {

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    struct event_base *ev_base;

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    const char *db_conninfo;

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    struct evsql *db;

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    struct evfuse *ev_fuse;

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};

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// XXX: not sure how this should work

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#define CACHE_TIMEOUT 1.0

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// columns used for stat_info

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#define DBFS_STAT_COLS " inodes.type, inodes.mode, dbfs_size(inodes.type, inodes.data, inodes.link_path), (SELECT COUNT(*) FROM inodes i LEFT JOIN file_tree ft ON (i.ino = ft.ino) WHERE i.ino = inodes.ino) AS nlink"

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/*

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 * Convert the CHAR(4) inodes.type from SQL into a mode_t.

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 *

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 * Returns zero for unknown types.

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 */

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mode_t _dbfs_mode (const char *type);

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/*

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 * Check that the number of rows and columns in the result set matches what we expect.

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 *

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 * If rows is nonzero, there must be exactly that many rows (mostly useful for rows=1).

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 * The number of columns must always be given, and match.

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 *

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 * Returns;

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 *  -1  if the query failed, the columns/rows do not match

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 *  0   the results match

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 *  1   there were no results (zero rows)

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 */

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int _dbfs_check_res (const struct evsql_result_info *res, size_t rows, size_t cols);

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/*

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 * Same as _dbfs_check_res, but returns ENOENT/EIO directly

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 */

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err_t dbfs_check_result (const struct evsql_result_info *res, size_t rows, size_t cols);

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/*

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 * Fill a `struct state` with info retrieved from a SQL query.

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 *

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 * The result must contain four columns, starting at the given offset:

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 *  inodes.type, inodes.mode, inodes.size, count(*) AS nlink

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 *

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 * Note that this does not fill the st_ino field

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 */

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int _dbfs_stat_info (struct stat *st, const struct evsql_result_info *res, size_t row, size_t col_offset);

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/** interrupt.c 

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 *  

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 * Fuse interrupts are handled using fuse_req_interrupt_func. Calling this registers a callback function with the req,

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 * which may or may not be called either by fuse_req_interrupt_func, or later on via evfuse's event handler. It is

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 * assumed that this will never be called after a call to fuse_reply_*.

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 *

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 * Hence, to handle an interrupt, we must first ensure that fuse_reply_* will not be called afterwards (it'll return

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 * an error), and then we must call fuse_reply_err(req, EINTR).

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 *

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 * In the simplest case, we can simply submit a query, and then abort it once the req is interrupted (now or later).

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 * In the more complicated case, we can check if the request was interrupted, if not, do the query and handle

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 * interrupts.

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 */

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/*

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 * Useable as a callback to fuse_req_interrupt_func, will abort the given query and err the req.

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 */

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void dbfs_interrupt_query (struct fuse_req *req, void *query_ptr);

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/*

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 * XXX: More complicated state, is this actually needed?

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 */

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struct dbfs_interrupt_ctx {

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    struct fuse_req *req;

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    struct evsql_query *query;

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    int interrupted : 1;

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};

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/*

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 * Register as a fuse interrupt function for simple requests that only run one query without allocating any resources.

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 *

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 * This will abort the query if the interrupt is run, causing it's callback to not be called.

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 *

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 * Returns nonzero if the request was already interrupted, zero otherwise. Be careful that the interrupt does not get

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 * fired between you checking for it and setting query.

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 */

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int dbfs_interrupt_register (struct fuse_req *req, struct dbfs_interrupt_ctx *ctx);

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#endif /* DBFS_DBFS_H */