X-Git-Url: http://git.tuebingen.mpg.de/?p=osl.git;a=blobdiff_plain;f=osl.h.in;h=20e930ffae7b567c13ea72975ba1a636e589a290;hp=a586be293ac228382fc7413b508539bc425a2808;hb=41c4262daac7908ad77896e862811c4b34fe0532;hpb=f57b24f2f5b6d8ce5ca0d5ad67b5c086695d8eb2 diff --git a/osl.h.in b/osl.h.in index a586be2..20e930f 100644 --- a/osl.h.in +++ b/osl.h.in @@ -1,4 +1,3 @@ -#include /* * Copyright (C) 2007-2008 Andre Noll * @@ -7,7 +6,12 @@ /** \file osl.h User interface for the object storage layer. */ -/** describes an object of the object storage layer (osl) */ +#include + +/** Export all declarations in this file. */ +#pragma GCC visibility push(default) + +/** Describes an object of the object storage layer (osl) */ struct osl_object { /** Pointer to the data of the object. */ void *data; @@ -63,7 +67,9 @@ enum osl_storage_flags { OSL_DONT_FREE = 8 }; +/** Opaque osl table structure. */ struct osl_table; +/** Opaque osl row structure. */ struct osl_row; /** @@ -75,15 +81,20 @@ struct osl_row; */ 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; +/** + * The osl_rbreee_loop functions take a function pointer of this type. For each + * node in the rbtree, the given function is called. + * + * \sa osl_rbtree_loop(), osl_rbtree_loop_reverse(). + */ +typedef int osl_rbtree_loop_func(struct osl_row *row, void *data); /** * Describes one column of a osl table. */ struct osl_column_description { - /** One of zje tree possible types of storage */ + /** One of the tree possible types of storage */ enum osl_storage_type storage_type; /** Specifies further properties of the column */ enum osl_storage_flags storage_flags; @@ -146,36 +157,348 @@ enum osl_close_flags { OSL_FREE_VOLATILE = 2 }; - - +/** + * Create a new osl table. + * + * \param desc Pointer to the table description. + * + * \return Standard. + */ int osl_create_table(const struct osl_table_description *desc); + +/** + * Open an osl table. + * + * Each osl table must be opened before its data can be accessed. + * + * \param table_desc Describes the table to be opened. + * \param result Contains a pointer to the open table on success. + * + * The table description given by \a desc should coincide with the + * description used at creation time. + * + * \return Standard. + */ int osl_open_table(const struct osl_table_description *desc, struct osl_table **result); + +/** + * Close an osl table. + * + * \param t Pointer to the table to be closed. + * \param flags Options for what should be cleaned up. + * + * If osl_open_table() succeeds, the resulting table pointer must later be + * passed to this function in order to flush all changes to the file system and + * to free the resources that were allocated by osl_open_table(). + * + * \return Standard. + * + * \sa osl_open_table(), unmap_table(). + */ int osl_close_table(struct osl_table *t, enum osl_close_flags flags); + +/** + * Get the row that contains the given object. + * + * \param t Pointer to an open osl table. + * \param col_num The number of the column to be searched. + * \param obj The object to be looked up. + * \param result Points to the row containing \a obj. + * + * Lookup \a obj in \a t and return the row containing \a obj. The column + * specified by \a col_num must have an associated rbtree. + * + * \return Standard. + * + * \sa osl_storage_flags + */ int osl_get_row(const struct osl_table *t, unsigned col_num, const struct osl_object *obj, struct osl_row **result); + +/** + * Retrieve an object identified by row and column + * + * \param t Pointer to an open osl table. + * \param r Pointer to the row. + * \param col_num The column number. + * \param object The result pointer. + * + * The column determined by \a col_num must be of type \p OSL_MAPPED_STORAGE + * or \p OSL_NO_STORAGE, i.e. no disk storage objects may be retrieved by this + * function. + * + * \return Standard. + * + * \sa osl_storage_type, osl_open_disk_object(). + */ int osl_get_object(const struct osl_table *t, const struct osl_row *row, unsigned col_num, struct osl_object *object); + +/** + * Retrieve an object of type \p OSL_DISK_STORAGE by row and column. + * + * \param t Pointer to an open osl table. + * \param r Pointer to the row containing the object. + * \param col_num The column number. + * \param obj Points to the result upon successful return. + * + * For columns of type \p OSL_DISK_STORAGE, this function must be used to + * retrieve one of its containing objects. Afterwards, osl_close_disk_object() + * must be called in order to deallocate the resources. + * + * \return Standard. + * + * \sa osl_get_object(), osl_storage_type, osl_close_disk_object(). + */ int osl_open_disk_object(const struct osl_table *t, const struct osl_row *r, unsigned col_num, struct osl_object *obj); + +/** + * Free resources that were allocated during osl_open_disk_object(). + * + * \param obj Pointer to the object previously returned by open_disk_object(). + * + * \return The return value of the underlying call to para_munmap(). + * + * \sa para_munmap(). + */ int osl_close_disk_object(struct osl_object *obj); + +/** + * Add a new row to an osl table and retrieve this row. + * + * \param t Pointer to an open osl table. + * \param objects Array of objects to be added. + * \param row Result pointer. + * + * The \a objects parameter must point to an array containing one object per + * column. The order of the objects in the array is given by the table + * description of \a table. Several sanity checks are performed during object + * insertion and the function returns without modifying the table if any of + * these tests fail. In fact, it is atomic in the sense that it either + * succeeds or leaves the table unchanged (i.e. either all or none of the + * objects are added to the table). + * + * It is considered an error if an object is added to a column with associated + * rbtree if this object is equal to an object already contained in that column + * (i.e. the compare function for the column's rbtree returns zero). + * + * \return Standard. + * + * \sa struct osl_table_description, osl_compare_func, osl_add_row(). + */ int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects, struct osl_row **row); + + +/** + * Add a new row to an osl table. + * + * \param t Same meaning as osl_add_and_get_row(). + * \param objects Same meaning as osl_add_and_get_row(). + * + * \return The return value of the underlying call to osl_add_and_get_row(). + * + * This is equivalent to osl_add_and_get_row(t, objects, NULL). + */ int osl_add_row(struct osl_table *t, struct osl_object *objects); + +/** + * Delete a row from an osl table. + * + * \param t Pointer to an open osl table. + * \param row Pointer to the row to delete. + * + * This removes all disk storage objects, removes all rbtree nodes, and frees + * all volatile objects belonging to the given row. For mapped columns, the + * data is merely marked invalid and may be pruned from time to time by + * para_fsck. + * + * \return Standard. + */ int osl_del_row(struct osl_table *t, struct osl_row *row); + +/** + * Loop over all nodes in an rbtree. + * + * \param t Pointer to an open osl table. + * \param col_num The column to use for iterating over the elements. + * \param private_data Pointer that gets passed to \a func. + * \param func The function to be called for each node in the rbtree. + * + * This function does an in-order walk of the rbtree associated with \a + * col_num. It is an error if the \p OSL_RBTREE flag is not set for this + * column. For each node in the rbtree, the given function \a func is called + * with two pointers as arguments: The first osl_row* argument points to the + * row that contains the object corresponding to the rbtree node currently + * traversed, and the \a private_data pointer is passed verbatim to \a func as the + * second argument. The loop terminates either if \a func returns a negative + * value, or if all nodes of the tree have been visited. + * + * + * \return Standard. If the termination of the loop was caused by \a func + * returning a negative value, \p -E_OSL_LOOP is returned. + * + * \sa osl_storage_flags, osl_rbtree_loop_reverse(), osl_compare_func. + */ int osl_rbtree_loop(const struct osl_table *t, unsigned col_num, void *private_data, osl_rbtree_loop_func *func); + +/** + * Loop over all nodes in an rbtree in reverse order. + * + * \param t Identical meaning as in \p osl_rbtree_loop(). + * \param col_num Identical meaning as in \p osl_rbtree_loop(). + * \param private_data Identical meaning as in \p osl_rbtree_loop(). + * \param func Identical meaning as in \p osl_rbtree_loop(). + * + * This function is identical to \p osl_rbtree_loop(), the only difference + * is that the tree is walked in reverse order. + * + * \return The same return value as \p osl_rbtree_loop(). + * + * \sa osl_rbtree_loop(). + */ int osl_rbtree_loop_reverse(const struct osl_table *t, unsigned col_num, void *private_data, osl_rbtree_loop_func *func); + +/** + * Change an object in an osl table. + * + * \param t Pointer to an open osl table. + * \param r Pointer to the row containing the object to be updated. + * \param col_num Number of the column containing the object to be updated. + * \param obj Pointer to the replacement object. + * + * This function gets rid of all references to the old object. This includes + * removal of the rbtree node in case there is an rbtree associated with \a + * col_num. It then inserts \a obj into the table and the rbtree if necessary. + * + * If the \p OSL_RBTREE flag is set for \a col_num, you \b MUST call this + * function in order to change the contents of an object, even for volatile or + * mapped columns of constant size (which may be updated directly if \p + * OSL_RBTREE is not set). Otherwise the rbtree might become corrupted. + * + * \return Standard + */ int osl_update_object(struct osl_table *t, const struct osl_row *r, unsigned col_num, struct osl_object *obj); + +/** + * Get the number of rows of the given table. + * + * \param t Pointer to an open osl table. + * \param num_rows Result is returned here. + * + * The number of rows returned via \a num_rows excluding any invalid rows. + * + * \return Positive on success, \p -E_OSL_BAD_TABLE if \a t is \p NULL. + */ int osl_get_num_rows(const struct osl_table *t, unsigned *num_rows); + + +/** + * Get the row corresponding to the smallest rbtree node of a column. + * + * \param t An open rbtree table. + * \param col_num The number of the rbtree column. + * \param result A pointer to the first row is returned here. + * + * The rbtree node of the smallest object (with respect to the corresponding + * compare function) is selected and the row containing this object is + * returned. It is an error if \a col_num refers to a column without an + * associated rbtree. + * + * \return Standard. + * + * \sa osl_get_nth_row(), osl_rbtree_last_row(). + */ int osl_rbtree_first_row(const struct osl_table *t, unsigned col_num, struct osl_row **result); + +/** + * Get the row corresponding to the greatest rbtree node of a column. + * + * \param t The same meaning as in \p osl_rbtree_first_row(). + * \param col_num The same meaning as in \p osl_rbtree_first_row(). + * \param result The same meaning as in \p osl_rbtree_first_row(). + * + * This function works just like osl_rbtree_first_row(), the only difference + * is that the row containing the greatest rather than the smallest object is + * returned. + * + * \return Standard. + * + * \sa osl_get_nth_row(), osl_rbtree_first_row(). + */ int osl_rbtree_last_row(const struct osl_table *t, unsigned col_num, struct osl_row **result); + +/** + * Get the row with n-th greatest value. + * + * \param t Pointer to an open osl table. + * \param col_num The column number. + * \param n The rank of the desired row. + * \param result Row is returned here. + * + * Retrieve the n-th order statistic with respect to the compare function + * of the rbtree column \a col_num. In other words, get that row with + * \a n th greatest value in column \a col_num. It's an error if + * \a col_num is not a rbtree column, or if \a n is larger than the + * number of rows in the table. + * + * \return Standard. + * + * \sa osl_storage_flags, osl_compare_func, osl_get_row(), + * osl_rbtree_last_row(), osl_rbtree_first_row(), osl_get_rank(). + */ int osl_get_nth_row(const struct osl_table *t, unsigned col_num, unsigned n, struct osl_row **result); + +/** + * Get the rank of a row. + * + * \param t An open osl table. + * \param r The row to get the rank of. + * \param col_num The number of an rbtree column. + * \param rank Result pointer. + * + * The rank is, by definition, the position of the row in the linear order + * determined by an in-order tree walk of the rbtree associated with column + * number \a col_num of \a table. + * + * \return Standard. + * + * \sa osl_get_nth_row(). + */ int osl_get_rank(const struct osl_table *t, struct osl_row *r, unsigned col_num, unsigned *rank); -const char *osl_strerror(int nr); + +/** + * Compare two osl objects pointing to hash values. + * + * \param obj1 Pointer to the first hash object. + * \param obj2 Pointer to the second hash object. + * + * \return The values required for an osl compare function. + * + * \sa osl_compare_func, uint32_compare(). + */ +int osl_hash_compare(const struct osl_object *obj1, + const struct osl_object *obj2); + +/** + * Get a string describing the error code passed in the argument. + * + * \param num The error code. + * + * This works just like strerror(3). The given number must be an osl error + * code. The result must not be freed by the caller. + * + * \return The error text corresponding to an osl error code. + */ +const char *osl_strerror(int num); + +#pragma GCC visibility pop