| 1 | /* |
| 2 | * index.h: Manage indexes for agedu. |
| 3 | */ |
| 4 | |
| 5 | #include <sys/types.h> |
| 6 | |
| 7 | /* |
| 8 | * Given the size of an existing data file and the number of |
| 9 | * entries required in the index, return the file size required to |
| 10 | * store the fixed initial fragment of the index before the |
| 11 | * indexbuild functions are invoked. |
| 12 | */ |
| 13 | off_t index_initial_size(off_t currentsize, int nodecount); |
| 14 | |
| 15 | /* |
| 16 | * Build an index, given the address of a memory-mapped data file |
| 17 | * and the starting offset within it. |
| 18 | * |
| 19 | * trie_file structures passed to tf must of course be within the |
| 20 | * bounds of the memory-mapped file. |
| 21 | * |
| 22 | * The "delta" parameter to indexbuild_new is filled in with the |
| 23 | * maximum size by which the index can ever grow in a single |
| 24 | * indexbuild_add call. This can be used, together with |
| 25 | * indexbuild_realsize, to detect when the index is about to get |
| 26 | * too big for its file and the file needs resizing. |
| 27 | * |
| 28 | * indexbuild_add adds a trie_file structure to the index. |
| 29 | * indexbuild_tag, called after that, causes the current state of |
| 30 | * the index to be preserved so that it can be queried later. It's |
| 31 | * idempotent, and will safely do nothing if called before |
| 32 | * indexbuild_add. |
| 33 | * |
| 34 | * indexbuild_realsize returns the total amount of data _actually_ |
| 35 | * written into the file, to allow it to be truncated afterwards, |
| 36 | * and to allow the caller of the indexbuild functions to know |
| 37 | * when the file is about to need to grow bigger during index |
| 38 | * building. |
| 39 | * |
| 40 | * indexbuild_rebase is used when the file has been |
| 41 | * re-memory-mapped at a different address (because it needs to |
| 42 | * grow). |
| 43 | */ |
| 44 | typedef struct indexbuild indexbuild; |
| 45 | indexbuild *indexbuild_new(void *t, off_t startoff, int nodecount, |
| 46 | size_t *delta); |
| 47 | void indexbuild_add(indexbuild *ib, const struct trie_file *tf); |
| 48 | void indexbuild_tag(indexbuild *ib); |
| 49 | void indexbuild_rebase(indexbuild *ib, void *t); |
| 50 | off_t indexbuild_realsize(indexbuild *ib); |
| 51 | void indexbuild_free(indexbuild *ib); |
| 52 | |
| 53 | /* |
| 54 | * Check to see if a name index has an index tree root available |
| 55 | * (i.e. represents a directory rather than a file). |
| 56 | */ |
| 57 | int index_has_root(const void *t, int n); |
| 58 | |
| 59 | /* |
| 60 | * Query an index to find the total size of records with name |
| 61 | * index strictly less than n, with atime less than at. |
| 62 | */ |
| 63 | unsigned long long index_query(const void *t, int n, unsigned long long at); |
| 64 | |
| 65 | /* |
| 66 | * Retrieve an order statistic from the index: given a fraction f, |
| 67 | * return an atime such that (at most) the requested fraction of |
| 68 | * the total data is older than it. |
| 69 | */ |
| 70 | unsigned long long index_order_stat(const void *t, double f); |