#include /* * Copyright (C) 2007-2008 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ /** \file osl.h User interface for the object storage layer. */ /** describes an object of the object storage layer (osl) */ struct osl_object { /** Pointer to the data of the object. */ void *data; /** The object's size. */ size_t size; }; /** Flags that change the internal handling of osl tables. */ enum osl_table_flags { /** This table will have many rows. */ OSL_LARGE_TABLE = 1 }; /** The three different types of storage for an osl column */ enum osl_storage_type { /** * All data for this column is stored in one file which gets mmapped by * osl_open_table(). This is suitable for columns that do not hold much * data. */ OSL_MAPPED_STORAGE, /** * Each entry is stored on disk and is loaded on demand by * open_disk_object(). This is the preferable storage type for large * objects that need not be in memory all the time. */ OSL_DISK_STORAGE, /** * Objects for columns of this type are volatile: They are only stored * in memory and are discarded once the table gets closed. */ OSL_NO_STORAGE }; /** * Additional per-column flags */ enum osl_storage_flags { /** * Build an rbtree for this column. This is only possible if the * storage type of the column is either \a OSL_MAPPED_STORAGE or \a * OSL_NO_STORAGE. In order to lookup objects in the table by using \a * osl_get_row(), the lookup column must have an associated rbtree. * * \sa osl_storage_type, osl_get_row() */ OSL_RBTREE = 1, /** The data for this column will have constant size. */ OSL_FIXED_SIZE = 2, /** All values of this column will be different. */ OSL_UNIQUE = 4, /** Do not free the data for this column (\p OSL_NO_STORAGE). */ OSL_DONT_FREE = 8 }; struct osl_table; struct osl_row; /** * In order to build up an rbtree a compare function for the objects must be * specified. Such a function always takes pointers to the two objects to be * compared. It must return -1, zero, or 1, if the first argument is considered * to be respectively less than, equal to, or greater than the second. If two * members compare as equal, their order in the sorted array is undefined. */ typedef int osl_compare_func(const struct osl_object *obj1, const struct osl_object *obj2); typedef int osl_rbtree_loop_func(struct osl_row *row, void *data); osl_compare_func osl_hash_compare, uint32_compare; /** * Describes one column of a osl table. */ struct osl_column_description { /** One of zje tree possible types of storage */ enum osl_storage_type storage_type; /** Specifies further properties of the column */ enum osl_storage_flags storage_flags; /** * The column name determines the name of the directory where all data * for this column will be stored. Its hash is stored in the table * header. This field is ignored if the storage type is \a NO_STORAGE */ char *name; /** * For columns with an associated rbtree, this must point to a function * that compares the values of two objects, either a built-in function * or a function defined by the application may be supplied. This * field is ignored if the column does not have an associated rbtree. * * \sa osl_storage_flags, osl_compare_func */ osl_compare_func *compare_function; /** * If the \a OSL_FIXED_SIZE flag is set for this column, this value * determines the fixed size of all objects of this column. It is * ignored, if \a OSL_FIXED_SIZE is not set. */ uint32_t data_size; }; /** * Describes one osl table. */ struct osl_table_description { /** The directory which contains all files of this table. */ const char *dir; /** * The table name. A subdirectory of \a dir called \a name is created * at table creation time. It must be a valid name for a subdirectory. * In particular, no slashes are allowed for \a name. */ const char *name; /** The number of columns of this table. */ uint16_t num_columns; /** Further table-wide information. */ enum osl_table_flags flags; /** The array describing the individual columns of the table. */ struct osl_column_description *column_descriptions; }; /** Flags to be passed to \a osl_close_table(). */ enum osl_close_flags { /** * The table header contains a "dirty" flag which specifies whether * the table is currently open by another process. This flag specifies * that the dirty flag should be cleared before closing the table. */ OSL_MARK_CLEAN = 1, /** * If the table contains columns of type \a OSL_NO_STORAGE and this * flag is passed to osl_close_table(), free(3) is called for each * object of each column of type \a OSL_NO_STORAGE. */ OSL_FREE_VOLATILE = 2 }; int osl_create_table(const struct osl_table_description *desc); int osl_open_table(const struct osl_table_description *desc, struct osl_table **result); int osl_close_table(struct osl_table *t, enum osl_close_flags flags); int osl_get_row(const struct osl_table *t, unsigned col_num, const struct osl_object *obj, struct osl_row **result); int osl_get_object(const struct osl_table *t, const struct osl_row *row, unsigned col_num, struct osl_object *object); int osl_open_disk_object(const struct osl_table *t, const struct osl_row *r, unsigned col_num, struct osl_object *obj); int osl_close_disk_object(struct osl_object *obj); int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects, struct osl_row **row); int osl_add_row(struct osl_table *t, struct osl_object *objects); int osl_del_row(struct osl_table *t, struct osl_row *row); int osl_rbtree_loop(const struct osl_table *t, unsigned col_num, void *private_data, osl_rbtree_loop_func *func); int osl_rbtree_loop_reverse(const struct osl_table *t, unsigned col_num, void *private_data, osl_rbtree_loop_func *func); int osl_update_object(struct osl_table *t, const struct osl_row *r, unsigned col_num, struct osl_object *obj); int osl_get_num_rows(const struct osl_table *t, unsigned *num_rows); int osl_rbtree_first_row(const struct osl_table *t, unsigned col_num, struct osl_row **result); int osl_rbtree_last_row(const struct osl_table *t, unsigned col_num, struct osl_row **result); int osl_get_nth_row(const struct osl_table *t, unsigned col_num, unsigned n, struct osl_row **result); int osl_get_rank(const struct osl_table *t, struct osl_row *r, unsigned col_num, unsigned *rank); const char *osl_strerror(int nr);