diff options
Diffstat (limited to 'mysys/lf_hash.c')
| -rw-r--r-- | mysys/lf_hash.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/mysys/lf_hash.c b/mysys/lf_hash.c index c197cc99711..008abef0c8b 100644 --- a/mysys/lf_hash.c +++ b/mysys/lf_hash.c @@ -299,11 +299,22 @@ static int initialize_bucket(LF_HASH *, LF_SLIST * volatile*, uint, LF_PINS *); /* Initializes lf_hash, the arguments are compatible with hash_init + + @@note element_size sets both the size of allocated memory block for + lf_alloc and a size of memcpy'ed block size in lf_hash_insert. Typically + they are the same, indeed. But LF_HASH::element_size can be decreased + after lf_hash_init, and then lf_alloc will allocate larger block that + lf_hash_insert will copy over. It is desireable if part of the element + is expensive to initialize - for example if there is a mutex or + DYNAMIC_ARRAY. In this case they should be initialize in the + LF_ALLOCATOR::constructor, and lf_hash_insert should not overwrite them. + See wt_init() for example. */ void lf_hash_init(LF_HASH *hash, uint element_size, uint flags, uint key_offset, uint key_length, hash_get_key get_key, CHARSET_INFO *charset) { + compile_time_assert(sizeof(LF_SLIST) == LF_HASH_OVERHEAD); lf_alloc_init(&hash->alloc, sizeof(LF_SLIST)+element_size, offsetof(LF_SLIST, key)); lf_dynarray_init(&hash->array, sizeof(LF_SLIST *)); @@ -453,7 +464,7 @@ void *lf_hash_search(LF_HASH *hash, LF_PINS *pins, const void *key, uint keylen) return found ? found+1 : 0; } -static const uchar *dummy_key= ""; +static const uchar *dummy_key= (uchar*)""; /* RETURN @@ -473,7 +484,7 @@ static int initialize_bucket(LF_HASH *hash, LF_SLIST * volatile *node, unlikely(initialize_bucket(hash, el, parent, pins))) return -1; dummy->hashnr= my_reverse_bits(bucket) | 0; /* dummy node */ - dummy->key= (char*) dummy_key; + dummy->key= dummy_key; dummy->keylen= 0; if ((cur= linsert(el, hash->charset, dummy, pins, LF_HASH_UNIQUE))) { |