X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb2%2Ftdb2.h;h=47661da245352583f5491b440fec2e58b1ff0e68;hp=3374e0cac6ba310883be85c06e600ef822bd0f25;hb=9d9a9897b608af3a6acd623cc09557f9985b03e6;hpb=39b9d9ef8c05224b5f2685003160f4092fbd7045 diff --git a/ccan/tdb2/tdb2.h b/ccan/tdb2/tdb2.h index 3374e0ca..47661da2 100644 --- a/ccan/tdb2/tdb2.h +++ b/ccan/tdb2/tdb2.h @@ -40,6 +40,7 @@ extern "C" { #include #endif #include +#include union tdb_attribute; struct tdb_context; @@ -96,6 +97,25 @@ typedef struct tdb_data { size_t dsize; } TDB_DATA; +/** + * enum TDB_ERROR - error returns for TDB + * + * See Also: + * tdb_errorstr() + */ +enum TDB_ERROR { + TDB_SUCCESS = 0, /* No error. */ + TDB_ERR_CORRUPT = -1, /* We read the db, and it was bogus. */ + TDB_ERR_IO = -2, /* We couldn't read/write the db. */ + TDB_ERR_LOCK = -3, /* Locking failed. */ + TDB_ERR_OOM = -4, /* Out of Memory. */ + TDB_ERR_EXISTS = -5, /* The key already exists. */ + TDB_ERR_NOEXIST = -6, /* The key does not exist. */ + TDB_ERR_EINVAL = -7, /* You're using it wrong. */ + TDB_ERR_RDONLY = -8, /* The database is read-only. */ + TDB_ERR_LAST = TDB_ERR_RDONLY +}; + /** * tdb_store - store a key/value pair in a tdb. * @tdb: the tdb context returned from tdb_open() @@ -105,18 +125,18 @@ typedef struct tdb_data { * * This inserts (or overwrites) a key/value pair in the TDB. If flag * is TDB_REPLACE, it doesn't matter whether the key exists or not; - * TDB_INSERT means it must not exist (TDB_ERR_EXISTS otherwise), - * and TDB_MODIFY means it must exist (TDB_ERR_NOEXIST otherwise). + * TDB_INSERT means it must not exist (returns TDB_ERR_EXISTS otherwise), + * and TDB_MODIFY means it must exist (returns TDB_ERR_NOEXIST otherwise). * - * On success, this returns 0, on failure -1, and sets tdb_error(). + * On success, this returns TDB_SUCCESS. * * See also: * tdb_fetch, tdb_transaction_start, tdb_append, tdb_delete. */ -int tdb_store(struct tdb_context *tdb, - struct tdb_data key, - struct tdb_data dbuf, - int flag); +enum TDB_ERROR tdb_store(struct tdb_context *tdb, + struct tdb_data key, + struct tdb_data dbuf, + int flag); /* flags to tdb_store() */ #define TDB_REPLACE 1 /* A readability place holder */ @@ -127,55 +147,26 @@ int tdb_store(struct tdb_context *tdb, * tdb_fetch - fetch a value from a tdb. * @tdb: the tdb context returned from tdb_open() * @key: the key + * @data: pointer to data. * - * This looks up a key in the database and returns it, or returns tdb_null - * and sets tdb_error() if there's a problem (usually, TDB_ERR_NOEXIST). + * This looks up a key in the database and sets it in @data. * - * It is your responsibility to call free() on the returned structure's - * dptr. - */ -struct tdb_data tdb_fetch(struct tdb_context *tdb, struct tdb_data key); - -/** - * enum TDB_ERROR - error codes for TDB + * If it returns TDB_SUCCESS, the key was found: it is your + * responsibility to call free() on @data->dptr. * - * See Also: - * tdb_error(), tdb_errorstr() + * Otherwise, it returns an error (usually, TDB_ERR_NOEXIST) and @data is + * undefined. */ -enum TDB_ERROR { - TDB_SUCCESS=0, /* No error. */ - TDB_ERR_CORRUPT, /* We read the db, and it was bogus. */ - TDB_ERR_IO, /* We couldn't read/write the db. */ - TDB_ERR_LOCK, /* Locking failed. */ - TDB_ERR_OOM, /* Out of Memory. */ - TDB_ERR_EXISTS, /* The key already exists. */ - TDB_ERR_NOEXIST, /* The key does not exist. */ - TDB_ERR_EINVAL, /* You're using it wrong. */ - TDB_ERR_RDONLY /* The database is read-only. */ -}; - -/** - * tdb_error - fetch the last error value from the tdb. - * @tdb: the tdb context returned from tdb_open() - * - * This returns the last error, or TDB_SUCCESS. It always returns TDB_SUCCESS - * immediately after tdb_open() returns the (non-NULL) tdb context. - * - * See Also: - * tdb_errorstr() - */ -enum TDB_ERROR tdb_error(const struct tdb_context *tdb); +enum TDB_ERROR tdb_fetch(struct tdb_context *tdb, struct tdb_data key, + struct tdb_data *data); /** * tdb_errorstr - map the tdb error onto a constant readable string - * @tdb: the tdb context returned from tdb_open() + * @ecode: the enum TDB_ERROR to map. * - * This is more useful for displaying errors to users than tdb_error. - * - * See Also: - * tdb_error() + * This is useful for displaying errors to users. */ -const char *tdb_errorstr(const struct tdb_context *tdb); +const char *tdb_errorstr(enum TDB_ERROR ecode); /** * tdb_append - append a value to a key/value pair in a tdb. @@ -188,27 +179,23 @@ const char *tdb_errorstr(const struct tdb_context *tdb); * doesn't exist, it's equivalent to tdb_store (with an additional hint that * you expect to expand the record in future). * - * Returns 0 on success, -1 on failure (and sets tdb_error()). - * * See Also: * tdb_fetch(), tdb_store() */ -int tdb_append(struct tdb_context *tdb, - struct tdb_data key, - struct tdb_data dbuf); +enum TDB_ERROR tdb_append(struct tdb_context *tdb, + struct tdb_data key, struct tdb_data dbuf); /** * tdb_delete - delete a key from a tdb. * @tdb: the tdb context returned from tdb_open() * @key: the key to delete. * - * Returns 0 on success, or -1 on error (usually tdb_error() would be - * TDB_ERR_NOEXIST in that case). + * Returns TDB_SUCCESS on success, or an error (usually TDB_ERR_NOEXIST). * * See Also: * tdb_fetch(), tdb_store() */ -int tdb_delete(struct tdb_context *tdb, struct tdb_data key); +enum TDB_ERROR tdb_delete(struct tdb_context *tdb, struct tdb_data key); /** * tdb_transaction_start - start a transaction @@ -218,12 +205,10 @@ int tdb_delete(struct tdb_context *tdb, struct tdb_data key); * to read the tdb, but not alter it (they will block), nor will they see * any changes until tdb_transaction_commit() is called. * - * On failure, returns -1 and sets tdb_error(). - * * See Also: * tdb_transaction_cancel, tdb_transaction_commit. */ -int tdb_transaction_start(struct tdb_context *tdb); +enum TDB_ERROR tdb_transaction_start(struct tdb_context *tdb); /** * tdb_transaction_cancel - abandon a transaction @@ -244,14 +229,13 @@ void tdb_transaction_cancel(struct tdb_context *tdb); * making it robust against machine crashes, but very slow compared to * other TDB operations. * - * Returns 0 on success, or -1 on failure: this can only be caused by - * unexpected errors (eg. I/O or memory); this is no point looping on - * transaction failure. + * A failure can only be caused by unexpected errors (eg. I/O or + * memory); this is no point looping on transaction failure. * * See Also: * tdb_transaction_prepare_commit() */ -int tdb_transaction_commit(struct tdb_context *tdb); +enum TDB_ERROR tdb_transaction_commit(struct tdb_context *tdb); /** * tdb_transaction_prepare_commit - prepare to commit a transaction @@ -261,15 +245,10 @@ int tdb_transaction_commit(struct tdb_context *tdb); * tdb_transaction_commit): if this succeeds then a transaction will only * fail if the write() or fsync() calls fail. * - * Returns 0 on success, or -1 on failure. - * * See Also: * tdb_transaction_commit() */ -int tdb_transaction_prepare_commit(struct tdb_context *tdb); - -/* FIXME: Make typesafe */ -typedef int (*tdb_traverse_func)(struct tdb_context *, TDB_DATA, TDB_DATA, void *); +enum TDB_ERROR tdb_transaction_prepare_commit(struct tdb_context *tdb); /** * tdb_traverse - traverse a TDB @@ -286,31 +265,43 @@ typedef int (*tdb_traverse_func)(struct tdb_context *, TDB_DATA, TDB_DATA, void * current key does not undermine the reliability of the traversal. * * On success, returns the number of keys iterated. On error returns - * -1 and sets tdb_error(). + * a negative enum TDB_ERROR value. */ -int64_t tdb_traverse(struct tdb_context *tdb, tdb_traverse_func fn, void *p); +#define tdb_traverse(tdb, fn, p) \ + tdb_traverse_(tdb, typesafe_cb_preargs(int, (fn), (p), \ + struct tdb_context *, \ + TDB_DATA, TDB_DATA), (p)) + +int64_t tdb_traverse_(struct tdb_context *tdb, + int (*fn)(struct tdb_context *, + TDB_DATA, TDB_DATA, void *), void *p); /** * tdb_firstkey - get the "first" key in a TDB * @tdb: the tdb context returned from tdb_open() + * @key: pointer to key. * * This returns an arbitrary key in the database; with tdb_nextkey() it allows - * open-coded traversal of the database. + * open-coded traversal of the database, though it is slightly less efficient + * than tdb_traverse. + * + * It is your responsibility to free @key->dptr on success. * - * On failure, returns tdb_null and sets tdb_error(). On success, returns - * a key, or tdb_null and set tdb_error() to TDB_SUCCESS for an empty database. + * Returns TDB_ERR_NOEXIST if the database is empty. */ -TDB_DATA tdb_firstkey(struct tdb_context *tdb); +enum TDB_ERROR tdb_firstkey(struct tdb_context *tdb, struct tdb_data *key); /** * tdb_nextkey - get the "next" key in a TDB * @tdb: the tdb context returned from tdb_open() * @key: a key returned by tdb_firstkey() or tdb_nextkey(). * - * This returns another key in the database. On failure or the last key - * it returns tdb_null: tdb_error() will be TDB_SUCCESS if it was the last key. + * This returns another key in the database; it will free @key.dptr for + * your convenience. + * + * Returns TDB_ERR_NOEXIST if there are no more keys. */ -TDB_DATA tdb_nextkey(struct tdb_context *tdb, TDB_DATA key); +enum TDB_ERROR tdb_nextkey(struct tdb_context *tdb, struct tdb_data *key); /** * tdb_chainlock - lock a record in the TDB @@ -328,30 +319,40 @@ TDB_DATA tdb_nextkey(struct tdb_context *tdb, TDB_DATA key); * See Also: * tdb_chainunlock() */ -int tdb_chainlock(struct tdb_context *tdb, TDB_DATA key); +enum TDB_ERROR tdb_chainlock(struct tdb_context *tdb, TDB_DATA key); /** * tdb_chainunlock - unlock a record in the TDB * @tdb: the tdb context returned from tdb_open() * @key: the key to unlock. */ -int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key); +enum TDB_ERROR tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key); /** * tdb_check - check a TDB for consistency * @tdb: the tdb context returned from tdb_open() * @check: function to check each key/data pair (or NULL) - * @private_data: pointer for @check + * @private: argument for @check, must match type. * * This performs a consistency check of the open database, optionally calling * a check() function on each record so you can do your own data consistency - * checks as well. If check() returns non-zero, it is considered a failure. + * checks as well. If check() returns an error, that is returned from + * tdb_check(). * - * Returns 0 on success, or -1 on failure and sets tdb_error(). + * Returns TDB_SUCCESS or an error. */ -int tdb_check(struct tdb_context *tdb, - int (*check)(TDB_DATA key, TDB_DATA data, void *private_data), - void *private_data); +#define tdb_check(tdb, check, private) \ + tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR, \ + (check), (private), \ + struct tdb_data, \ + struct tdb_data), \ + (private)) + +enum TDB_ERROR tdb_check_(struct tdb_context *tdb, + enum TDB_ERROR (*check)(struct tdb_data key, + struct tdb_data data, + void *private), + void *private); /** * enum tdb_summary_flags - flags for tdb_summary. @@ -364,22 +365,50 @@ enum tdb_summary_flags { * tdb_summary - return a string describing the TDB state * @tdb: the tdb context returned from tdb_open() * @flags: flags to control the summary output. + * @summary: pointer to string to allocate. * * This returns a developer-readable string describing the overall * state of the tdb, such as the percentage used and sizes of records. * It is designed to provide information about the tdb at a glance * without displaying any keys or data in the database. * - * On success, returns a nul-terminated multi-line string. On failure, - * returns NULL and sets tdb_error(). + * On success, sets @summary to point to a malloc()'ed nul-terminated + * multi-line string. It is your responsibility to free() it. */ -char *tdb_summary(struct tdb_context *tdb, enum tdb_summary_flags flags); - +enum TDB_ERROR tdb_summary(struct tdb_context *tdb, + enum tdb_summary_flags flags, + char **summary); + +/** + * tdb_get_flags - return the flags for a tdb + * @tdb: the tdb context returned from tdb_open() + * + * This returns the flags on the current tdb. Some of these are caused by + * the flags argument to tdb_open(), others (such as TDB_CONVERT) are + * intuited. + */ +unsigned int tdb_get_flags(struct tdb_context *tdb); -int64_t tdb_traverse_read(struct tdb_context *tdb, - tdb_traverse_func fn, void *p); +/** + * tdb_add_flag - set a flag for a tdb + * @tdb: the tdb context returned from tdb_open() + * @flag: one of TDB_NOLOCK, TDB_NOMMAP or TDB_NOSYNC. + * + * You can use this to set a flag on the TDB. You cannot set these flags + * on a TDB_INTERNAL tdb. + */ +void tdb_add_flag(struct tdb_context *tdb, unsigned flag); +/** + * tdb_remove_flag - unset a flag for a tdb + * @tdb: the tdb context returned from tdb_open() + * @flag: one of TDB_NOLOCK, TDB_NOMMAP or TDB_NOSYNC. + * + * You can use this to clear a flag on the TDB. You cannot clear flags + * on a TDB_INTERNAL tdb. + */ +void tdb_remove_flag(struct tdb_context *tdb, unsigned flag); /** * enum tdb_attribute_type - descriminator for union tdb_attribute.