Re: [Libvir] [PATCH 2/6] Inactive domain support: new virHash APIs

The attached patch adds a couple of new APIs to the hash table object to allow various different ways of iterating over the contents of the hash table. The methods are: virHashForEach virHashRemoveSet virHashSearch Docs for these methods are all inline. Compared to previous patch a logic flaw in the virHashRemoveSet method was fixed prevently some severe memory corruption!

Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|

Index: src/hash.c =================================================================== RCS file: /data/cvs/libvirt/src/hash.c,v retrieving revision 1.10 diff -c -r1.10 hash.c *** src/hash.c 21 Sep 2006 15:24:37 -0000 1.10 --- src/hash.c 15 Nov 2006 02:34:00 -0000 *************** *** 473,478 **** --- 473,597 ---- } } + + /** + * virHashForEach + * @table: the hash table to process + * @iter: callback to process each element + * @data: opaque data to pass to the iterator + * + * Iterates over every element in the hash table, invoking the + * 'iter' callback. The callback must not call any other virHash* + * functions, and in particular must not attempt to remove the + * element. + * + * Returns 0 on completion, -1 on failure + */

+ int virHashForEach(virHashTablePtr table, virHashIterator iter, const void *data) { + int i; + + if (table == NULL || iter == NULL) + return (-1); + + for (i = 0 ; i < table->size ; i++) { + virHashEntryPtr entry = table->table + i; + while (entry) { + if (entry->valid) { + iter(entry->payload, entry->name, data); + } + entry = entry->next; + } + } + return 0; + } + + /** + * virHashRemoveSet + * @table: the hash table to process + * @iter: callback to identify elements for removal + * @f: callback to free memory from element payload + * @data: opaque data to pass to the iterator + * + * Iterates over all elements in the hash table, invoking the 'iter' + * callback. If the callback returns a non-zero value, the element + * will be removed from the hash table & its payload passed to the + * callback 'f' for de-allocation. + * + * Returns 0 on success, -1 on failure + */

+ int virHashRemoveSet(virHashTablePtr table, virHashSearcher iter, virHashDeallocator f, const void *data) { + int i; + + if (table == NULL || iter == NULL) + return (-1); + + for (i = 0 ; i < table->size ; i++) { + virHashEntryPtr prev = NULL; + virHashEntryPtr entry = &(table->table[i]); + + while (entry && entry->valid) { + if (iter(entry->payload, entry->name, data)) { + f(entry->payload, entry->name); + if (entry->name) + free(entry->name); + if (prev) { + prev->next = entry->next; + free(entry); + } else { + if (entry->next == NULL) { + entry->valid = 0; + entry->name = NULL; + } else { + entry = entry->next; + memcpy(&(table->table[i]), entry, + sizeof(virHashEntry)); + free(entry); + entry = NULL; + } + } + table->nbElems--; + } + prev = entry; + if (entry) { + entry = entry->next; + } else { + entry = NULL; + } + } + } + return 0; + }

+ /** + * virHashSearch: + * @table: the hash table to search + * @iter: an iterator to identify the desired element + * @data: extra opaque information passed to the iter + * + * Iterates over the hash table calling the 'iter' callback + * for each element. The first element for which the iter + * returns non-zero will be returned by this function. + * The elements are processed in a undefined order + */ + void *virHashSearch(virHashTablePtr table, virHashSearcher iter, const void *data) { + int i; + + if (table == NULL || iter == NULL) + return (NULL); + + for (i = 0 ; i < table->size ; i++) { + virHashEntryPtr entry = table->table + i; + while (entry) { + if (entry->valid) { + if (iter(entry->payload, entry->name, data)) + return entry->payload; + } + entry = entry->next; + } + } + return (NULL); + }

/************************************************************************ * * * Domain and Connections allocations * *************** *** 770,772 **** --- 889,899 ---- xmlMutexUnlock(conn->domains_mux); return(ret); } + /* + * Local variables: + * indent-tabs-mode: nil + * c-indent-level: 4 + * c-basic-offset: 4 + * tab-width: 4 + * End: + */ Index: src/hash.h =================================================================== RCS file: /data/cvs/libvirt/src/hash.h,v retrieving revision 1.5 diff -c -r1.5 hash.h *** src/hash.h 9 Apr 2006 13:11:22 -0000 1.5 --- src/hash.h 15 Nov 2006 02:34:00 -0000 *************** *** 33,39 **** * * Callback to free data from a hash. */ ! typedef void (*virHashDeallocator) (void *payload, char *name); /* * Constructor and destructor. --- 33,41 ---- * * Callback to free data from a hash.

*/ ! typedef void (*virHashDeallocator) (void *payload, const char *name); ! typedef void (*virHashIterator) (const void *payload, const char *name, const void *data); ! typedef int (*virHashSearcher) (const void *payload, const char *name, const void *data); /* * Constructor and destructor. *************** *** 62,67 **** --- 64,75 ---- */ void *virHashLookup(virHashTablePtr table, const char *name);

+ + + int virHashForEach(virHashTablePtr table, virHashIterator iter, const void *data); + int virHashRemoveSet(virHashTablePtr table, virHashSearcher iter, virHashDeallocator f, const void *data); + void *virHashSearch(virHashTablePtr table, virHashSearcher iter, const void *data); + #ifdef __cplusplus } #endif