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2020-12-15strmap: make callers of strmap_remove() to call it in void contextJunio C Hamano
Two "static inline" functions, both of which return void, call strmap_remove() and tries to return the value it returns as their return value, which is just bogus, as strmap_remove() returns void itself. Call it in the void context and fall-thru the control to the end instead. Reported-by: Randall S. Becker <rsbecker@nexbridge.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-11strmap: take advantage of FLEXPTR_ALLOC_STR when relevantElijah Newren
By default, we do not use a mempool and strdup_strings is true; in this case, we can avoid both an extra allocation and an extra free by just over-allocating for the strmap_entry leaving enough space at the end to copy the key. FLEXPTR_ALLOC_STR exists for exactly this purpose, so make use of it. Also, adjust the case when we are using a memory pool and strdup_strings is true to just do one allocation from the memory pool instead of two so that the strmap_clear() and strmap_remove() code can just avoid freeing the key in all cases. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-11strmap: enable allocations to come from a mem_poolElijah Newren
For heavy users of strmaps, allowing the keys and entries to be allocated from a memory pool can provide significant overhead savings. Add an option to strmap_init_with_options() to specify a memory pool. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-06strmap: add a strset sub-typeElijah Newren
Similar to adding strintmap for special-casing a string -> int mapping, add a strset type for cases where we really are only interested in using strmap for storing a set rather than a mapping. In this case, we'll always just store NULL for the value but the different struct type makes it clearer than code comments how a variable is intended to be used. The difference in usage also results in some differences in API: a few things that aren't necessary or meaningful are dropped (namely, the free_values argument to *_clear(), and the *_get() function), and strset_add() is chosen as the API instead of strset_put(). Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-05strmap: add functions facilitating use as a string->int mapElijah Newren
Although strmap could be used as a string->int map, one either had to allocate an int for every entry and then deallocate later, or one had to do a bunch of casting between (void*) and (intptr_t). Add some special functions that do the casting. Also, rename put->set for such wrapper functions since 'put' implied there may be some deallocation needed if the string was already found in the map, which isn't the case when we're storing an int value directly in the void* slot instead of using the void* slot as a pointer to data. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-05strmap: enable faster clearing and reusing of strmapsElijah Newren
When strmaps are used heavily, such as is done by my new merge-ort algorithm, and strmaps need to be cleared but then re-used (because of e.g. picking multiple commits to cherry-pick, or due to a recursive merge having several different merges while recursing), free-ing and reallocating map->table repeatedly can add up in time, especially since it will likely be reallocated to a much smaller size but the previous merge provides a good guide to the right size to use for the next merge. Introduce strmap_partial_clear() to take advantage of this type of situation; it will act similar to strmap_clear() except that map->table's entries are zeroed instead of map->table being free'd. Making use of this function reduced the cost of clear_or_reinit_internal_opts() by about 20% in mert-ort, and dropped the overall runtime of my rebase testcase by just under 2%. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-05strmap: add more utility functionsElijah Newren
This adds a number of additional convienence functions I want/need: * strmap_get_size() * strmap_empty() * strmap_remove() * strmap_for_each_entry() * strmap_get_entry() I suspect the first four are self-explanatory. strmap_get_entry() is similar to strmap_get() except that instead of just returning the void* value that the string maps to, it returns the strmap_entry that contains both the string and the void* value (or NULL if the string isn't in the map). This is helpful because it avoids multiple lookups, e.g. in some cases a caller would need to call: * strmap_contains() to check that the map has an entry for the string * strmap_get() to get the void* value * <do some work to update the value> * strmap_put() to update/overwrite the value If the void* pointer returned really is a pointer, then the last step is unnecessary, but if the void* pointer is just cast to an integer then strmap_put() will be needed. In contrast, one can call strmap_get_entry() and then: * check if the string was in the map by whether the pointer is NULL * access the value via entry->value * directly update entry->value meaning that we can replace two or three hash table lookups with one. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-02strmap: new utility functionsElijah Newren
Add strmap as a new struct and associated utility functions, specifically for hashmaps that map strings to some value. The API is taken directly from Peff's proposal at https://lore.kernel.org/git/20180906191203.GA26184@sigill.intra.peff.net/ Note that similar string-list, I have a strdup_strings setting. However, unlike string-list, strmap_init() does not take a parameter for this setting and instead automatically sets it to 1; callers who want to control this detail need to instead call strmap_init_with_options(). (Future patches will add additional parameters to strmap_init_with_options()). Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>