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Diffstat (limited to 'libnetdata/dictionary/dictionary.h')
| -rw-r--r-- | libnetdata/dictionary/dictionary.h | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/libnetdata/dictionary/dictionary.h b/libnetdata/dictionary/dictionary.h new file mode 100644 index 00000000..391be4ee --- /dev/null +++ b/libnetdata/dictionary/dictionary.h @@ -0,0 +1,335 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#ifndef NETDATA_DICTIONARY_H +#define NETDATA_DICTIONARY_H 1 + +#include "../libnetdata.h" + + +/* + * Netdata DICTIONARY features: + * + * CLONE or LINK + * Names and Values in the dictionary can be cloned or linked. + * In clone mode, the dictionary does all the memory management. + * The default is clone for both names and values. + * Set DICT_OPTION_NAME_LINK_DONT_CLONE to link names. + * Set DICT_OPTION_VALUE_LINK_DONT_CLONE to link names. + * + * ORDERED + * Items are ordered in the order they are added (new items are appended at the end). + * You may reverse the order by setting the flag DICT_OPTION_ADD_IN_FRONT. + * + * LOOKUP + * The dictionary uses JudyHS to maintain a very fast randomly accessible hash table. + * + * MULTI-THREADED and SINGLE-THREADED + * Each dictionary may be single threaded (no locks), or multi-threaded (multiple readers or one writer). + * The default is multi-threaded. Add the flag DICT_OPTION_SINGLE_THREADED for single-threaded. + * + * WALK-THROUGH and FOREACH traversal + * The dictionary can be traversed on read or write mode, either with a callback (walkthrough) or with + * a loop (foreach). + * + * In write mode traversal, the caller may delete only the current item, but may add as many items as needed. + * + */ + +#ifdef NETDATA_INTERNAL_CHECKS +#define DICT_WITH_STATS 1 +#endif + +#ifdef DICTIONARY_INTERNALS +#define DICTFE_CONST +#define DICT_ITEM_CONST +#else +#define DICTFE_CONST const +#define DICT_ITEM_CONST const +#endif + +typedef struct dictionary DICTIONARY; +typedef struct dictionary_item DICTIONARY_ITEM; + +typedef enum __attribute__((packed)) dictionary_options { + DICT_OPTION_NONE = 0, // the default is the opposite of all below + DICT_OPTION_SINGLE_THREADED = (1 << 0), // don't use any locks (default: use locks) + DICT_OPTION_VALUE_LINK_DONT_CLONE = (1 << 1), // don't copy the value, just point to the one provided (default: copy) + DICT_OPTION_NAME_LINK_DONT_CLONE = (1 << 2), // don't copy the name, just point to the one provided (default: copy) + DICT_OPTION_DONT_OVERWRITE_VALUE = (1 << 3), // don't overwrite values of dictionary items (default: overwrite) + DICT_OPTION_ADD_IN_FRONT = (1 << 4), // add dictionary items at the front of the linked list (default: at the end) + DICT_OPTION_FIXED_SIZE = (1 << 5), // the items of the dictionary have a fixed size +} DICT_OPTIONS; + +struct dictionary_stats { + const char *name; // the name of the category + + struct { + size_t active; // the number of active dictionaries + size_t deleted; // the number of dictionaries queued for destruction + } dictionaries; + + struct { + long entries; // active items in the dictionary + long pending_deletion; // pending deletion items in the dictionary + long referenced; // referenced items in the dictionary + } items; + + struct { + size_t creations; // dictionary creations + size_t destructions; // dictionary destructions + size_t flushes; // dictionary flushes + size_t traversals; // dictionary foreach + size_t walkthroughs; // dictionary walkthrough + size_t garbage_collections; // dictionary garbage collections + size_t searches; // item searches + size_t inserts; // item inserts + size_t resets; // item resets + size_t deletes; // item deletes + } ops; + + struct { + size_t inserts; // number of times the insert callback is called + size_t conflicts; // number of times the conflict callback is called + size_t reacts; // number of times the react callback is called + size_t deletes; // number of times the delete callback is called + } callbacks; + + // memory + struct { + long index; // bytes of keys indexed (indication of the index size) + long values; // bytes of caller structures + long dict; // bytes of the structures dictionary needs + } memory; + + // spin locks + struct { + size_t use_spins; // number of times a reference to item had to spin to acquire it or ignore it + size_t search_spins; // number of times a successful search result had to be thrown away + size_t insert_spins; // number of times an insertion to the hash table had to be repeated + size_t delete_spins; // number of times a deletion had to spin to get a decision + } spin_locks; +}; + +// Create a dictionary +#ifdef NETDATA_INTERNAL_CHECKS +#define dictionary_create(options) dictionary_create_advanced_with_trace(options, NULL, 0, __FUNCTION__, __LINE__, __FILE__) +#define dictionary_create_advanced(options, stats, fixed_size) dictionary_create_advanced_with_trace(options, stats, fixed_size, __FUNCTION__, __LINE__, __FILE__) +DICTIONARY *dictionary_create_advanced_with_trace(DICT_OPTIONS options, struct dictionary_stats *stats, size_t fixed_size, const char *function, size_t line, const char *file); +#else +#define dictionary_create(options) dictionary_create_advanced(options, NULL, 0) +DICTIONARY *dictionary_create_advanced(DICT_OPTIONS options, struct dictionary_stats *stats, size_t fixed_size); +#endif + +// Create a view on a dictionary +#ifdef NETDATA_INTERNAL_CHECKS +#define dictionary_create_view(master) dictionary_create_view_with_trace(master, __FUNCTION__, __LINE__, __FILE__) +DICTIONARY *dictionary_create_view_with_trace(DICTIONARY *master, const char *function, size_t line, const char *file); +#else +DICTIONARY *dictionary_create_view(DICTIONARY *master); +#endif + +// an insert callback to be called just after an item is added to the dictionary +// this callback is called while the dictionary is write locked! +void dictionary_register_insert_callback(DICTIONARY *dict, void (*ins_callback)(const DICTIONARY_ITEM *item, void *value, void *data), void *data); + +// a delete callback to be called just before an item is deleted forever +// this callback is called while the dictionary is write locked! +void dictionary_register_delete_callback(DICTIONARY *dict, void (*del_callback)(const DICTIONARY_ITEM *item, void *value, void *data), void *data); + +// a merge callback to be called when DICT_OPTION_DONT_OVERWRITE_VALUE +// and an item is already found in the dictionary - the dictionary does nothing else in this case +// the old_value will remain in the dictionary - the new_value is ignored +// The callback should return true if the value has been updated (it increases the dictionary version). +void dictionary_register_conflict_callback(DICTIONARY *dict, bool (*conflict_callback)(const DICTIONARY_ITEM *item, void *old_value, void *new_value, void *data), void *data); + +// a reaction callback to be called after every item insertion or conflict +// after the constructors have finished and the items are fully available for use +// and the dictionary is not write locked anymore +void dictionary_register_react_callback(DICTIONARY *dict, void (*react_callback)(const DICTIONARY_ITEM *item, void *value, void *data), void *data); + +// Destroy a dictionary +// Returns the number of bytes freed +// The returned value will not include name/key sizes +// Registered delete callbacks will be run for each item in the dictionary. +size_t dictionary_destroy(DICTIONARY *dict); + +// Empties a dictionary +// Referenced items will survive, but are not offered anymore. +// Registered delete callbacks will be run for each item in the dictionary. +void dictionary_flush(DICTIONARY *dict); + +void dictionary_version_increment(DICTIONARY *dict); + +void dictionary_garbage_collect(DICTIONARY *dict); + +void cleanup_destroyed_dictionaries(void); + +// ---------------------------------------------------------------------------- +// Set an item in the dictionary +// +// - if an item with the same name does not exist, create one +// - if an item with the same name exists, then: +// a) if DICT_OPTION_DONT_OVERWRITE_VALUE is set, just return the existing value (ignore the new value) +// else b) reset the value to the new value passed at the call +// +// When DICT_OPTION_VALUE_LINK_DONT_CLONE is set, the value is linked, otherwise it is copied +// When DICT_OPTION_NAME_LINK_DONT_CLONE is set, the name is linked, otherwise it is copied +// +// When neither DICT_OPTION_VALUE_LINK_DONT_CLONE nor DICT_OPTION_NAME_LINK_DONT_CLONE are set, all the +// memory management for names and values is done by the dictionary. +// +// Passing NULL as value, the dictionary will callocz() the newly allocated value, otherwise it will copy it. +// Passing 0 as value_len, the dictionary will set the value to NULL (no allocations for value will be made). +#define dictionary_set(dict, name, value, value_len) dictionary_set_advanced(dict, name, -1, value, value_len, NULL) +void *dictionary_set_advanced(DICTIONARY *dict, const char *name, ssize_t name_len, void *value, size_t value_len, void *constructor_data); + +#define dictionary_set_and_acquire_item(dict, name, value, value_len) dictionary_set_and_acquire_item_advanced(dict, name, -1, value, value_len, NULL) +DICT_ITEM_CONST DICTIONARY_ITEM *dictionary_set_and_acquire_item_advanced(DICTIONARY *dict, const char *name, ssize_t name_len, void *value, size_t value_len, void *constructor_data); + +// set an item in a dictionary view +#define dictionary_view_set_and_acquire_item(dict, name, master_item) dictionary_view_set_and_acquire_item_advanced(dict, name, -1, master_item) +DICT_ITEM_CONST DICTIONARY_ITEM *dictionary_view_set_and_acquire_item_advanced(DICTIONARY *dict, const char *name, ssize_t name_len, DICTIONARY_ITEM *master_item); +#define dictionary_view_set(dict, name, master_item) dictionary_view_set_advanced(dict, name, -1, master_item) +void *dictionary_view_set_advanced(DICTIONARY *dict, const char *name, ssize_t name_len, DICT_ITEM_CONST DICTIONARY_ITEM *master_item); + +// ---------------------------------------------------------------------------- +// Get an item from the dictionary +// If it returns NULL, the item is not found + +#define dictionary_get(dict, name) dictionary_get_advanced(dict, name, -1) +void *dictionary_get_advanced(DICTIONARY *dict, const char *name, ssize_t name_len); + +#define dictionary_get_and_acquire_item(dict, name) dictionary_get_and_acquire_item_advanced(dict, name, -1) +DICT_ITEM_CONST DICTIONARY_ITEM *dictionary_get_and_acquire_item_advanced(DICTIONARY *dict, const char *name, ssize_t name_len); + + +// ---------------------------------------------------------------------------- +// Delete an item from the dictionary +// returns true if the item was found and has been deleted +// returns false if the item was not found in the index + +#define dictionary_del(dict, name) dictionary_del_advanced(dict, name, -1) +bool dictionary_del_advanced(DICTIONARY *dict, const char *name, ssize_t name_len); + +// ---------------------------------------------------------------------------- +// reference counters management + +void dictionary_acquired_item_release(DICTIONARY *dict, DICT_ITEM_CONST DICTIONARY_ITEM *item); + +DICT_ITEM_CONST DICTIONARY_ITEM *dictionary_acquired_item_dup(DICTIONARY *dict, DICT_ITEM_CONST DICTIONARY_ITEM *item); + +const char *dictionary_acquired_item_name(DICT_ITEM_CONST DICTIONARY_ITEM *item); +void *dictionary_acquired_item_value(DICT_ITEM_CONST DICTIONARY_ITEM *item); + +size_t dictionary_acquired_item_references(DICT_ITEM_CONST DICTIONARY_ITEM *item); + +// ---------------------------------------------------------------------------- +// Traverse (walk through) the items of the dictionary. +// The order of traversal is currently the order of insertion. +// +// The callback function may return a negative number to stop the traversal, +// in which case that negative value is returned to the caller. +// +// If all callback calls return zero or positive numbers, the sum of all of +// them is returned to the caller. +// +// You cannot alter the dictionary from inside a dictionary_walkthrough_read() - deadlock! +// You can only delete the current item from inside a dictionary_walkthrough_write() - you can add as many as you want. +// +#define dictionary_walkthrough_read(dict, callback, data) dictionary_walkthrough_rw(dict, 'r', callback, data) +#define dictionary_walkthrough_write(dict, callback, data) dictionary_walkthrough_rw(dict, 'w', callback, data) +int dictionary_walkthrough_rw(DICTIONARY *dict, char rw, int (*callback)(const DICTIONARY_ITEM *item, void *value, void *data), void *data); + +typedef int (*dictionary_sorted_compar)(const DICTIONARY_ITEM **item1, const DICTIONARY_ITEM **item2); + +#define dictionary_sorted_walkthrough_read(dict, callback, data) dictionary_sorted_walkthrough_rw(dict, 'r', callback, data, NULL) +#define dictionary_sorted_walkthrough_write(dict, callback, data) dictionary_sorted_walkthrough_rw(dict, 'w', callback, data, NULL) +int dictionary_sorted_walkthrough_rw(DICTIONARY *dict, char rw, int (*callback)(const DICTIONARY_ITEM *item, void *entry, void *data), void *data, dictionary_sorted_compar compar); + +// ---------------------------------------------------------------------------- +// Traverse with foreach +// +// Use like this: +// +// DICTFE dfe = {}; +// for(MY_ITEM *item = dfe_start_read(&dfe, dict); item ; item = dfe_next(&dfe)) { +// // do things with the item and its dfe.name +// } +// dfe_done(&dfe); +// +// You cannot alter the dictionary from within a dfe_read_start() - deadlock! +// You can only delete the current item from inside a dfe_start_write() - you can add as many as you want. +// + +#define DICTIONARY_LOCK_READ 'r' +#define DICTIONARY_LOCK_WRITE 'w' +#define DICTIONARY_LOCK_REENTRANT 'z' + +void dictionary_write_lock(DICTIONARY *dict); +void dictionary_write_unlock(DICTIONARY *dict); + +typedef DICTFE_CONST struct dictionary_foreach { + DICTIONARY *dict; // the dictionary upon we work + + DICTIONARY_ITEM *item; // the item we work on, to remember the position we are at + // this can be used with dictionary_acquired_item_dup() to + // acquire the currently working item. + + const char *name; // the dictionary name of the last item used + void *value; // the dictionary value of the last item used + // same as the return value of dictfe_start() and dictfe_next() + + size_t counter; // counts the number of iterations made, starting from zero + + char rw; // the lock mode 'r' or 'w' + bool locked; // true when the dictionary is locked +} DICTFE; + +#define dfe_start_read(dict, value) dfe_start_rw(dict, value, DICTIONARY_LOCK_READ) +#define dfe_start_write(dict, value) dfe_start_rw(dict, value, DICTIONARY_LOCK_WRITE) +#define dfe_start_reentrant(dict, value) dfe_start_rw(dict, value, DICTIONARY_LOCK_REENTRANT) + +#define dfe_start_rw(dict, value, mode) \ + do { \ + DICTFE value ## _dfe = {}; \ + (void)(value); /* needed to avoid warning when looping without using this */ \ + for((value) = dictionary_foreach_start_rw(&value ## _dfe, (dict), (mode)); \ + (value ## _dfe.item) ; \ + (value) = dictionary_foreach_next(&value ## _dfe)) \ + { + +#define dfe_done(value) \ + } \ + dictionary_foreach_done(&value ## _dfe); \ + } while(0) + +#define dfe_unlock(value) dictionary_foreach_unlock(&value ## _dfe); + +void *dictionary_foreach_start_rw(DICTFE *dfe, DICTIONARY *dict, char rw); +void *dictionary_foreach_next(DICTFE *dfe); +void dictionary_foreach_done(DICTFE *dfe); +void dictionary_foreach_unlock(DICTFE *dfe); + +// ---------------------------------------------------------------------------- +// Get statistics about the dictionary + +size_t dictionary_version(DICTIONARY *dict); +size_t dictionary_entries(DICTIONARY *dict); +size_t dictionary_referenced_items(DICTIONARY *dict); + +// for all cases that the caller does not provide a stats structure, this is where they are accumulated. +extern struct dictionary_stats dictionary_stats_category_other; + +int dictionary_unittest(size_t entries); + +// ---------------------------------------------------------------------------- +// THREAD CACHE + +void *thread_cache_entry_get_or_set(void *key, + ssize_t key_length, + void *value, + void *(*transform_the_value_before_insert)(void *key, size_t key_length, void *value)); + +void thread_cache_destroy(void); + +#endif /* NETDATA_DICTIONARY_H */ |