/*
- * Copyright (C) 2007-2008 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2007-2009 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
/** \file osl.h User interface for the object storage layer. */
#include <sys/mman.h>
+#include <inttypes.h>
/** Export all declarations in this file. */
#pragma GCC visibility push(default)
* Describes one column of a osl table.
*/
struct osl_column_description {
- /** 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;
+ /** One of the tree possible types of storage, \sa osl_storage_type. */
+ uint16_t storage_type;
+ /** Specifies further properties of the column, \sa osl_storage_flags. */
+ uint16_t 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
const char *name;
/** The number of columns of this table. */
uint16_t num_columns;
- /** Further table-wide information. */
- enum osl_table_flags flags;
+ /** Further table-wide information, \sa osl_table_flags. */
+ uint8_t flags;
/** The array describing the individual columns of the table. */
struct osl_column_description *column_descriptions;
};
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 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 row 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 munmap().
+ *
+ * \sa munmap(2).
+ */
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
+ * osl_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);
-int osl_hash_compare(const struct osl_object *obj1,
- const struct osl_object *obj2);
-const char *osl_strerror(int nr);
+
+/**
+ * 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
projects / osl.git / blobdiff