Introduction of a new function in the LRU cache source file.
Purpose of this function is to be used to delete a number of entries in
the cache. 'number' is defined by the caller and the key removed are
taken at the tail of the tree
Commit 7810ad7 ("BUG/MAJOR: lru: fix unconditional call to free due to
unexpected semi-colon") was not enough, it happens that the free() is
not performed at the right place because if the evicted node is recycled,
we must also release its data before it gets overwritten.
No backport is needed.
Dmitry Sivachenko reported the following build warning using Clang, which
is a real bug :
src/lru.c:133:32: warning: if statement has empty body [-Wempty-body]
if (old->data && old->free);
^
It results in calling old->free(old->data) even when old->free is NULL,
hence crashing on cached patterns.
The same bug appears a few lines below in lru64_destroy() :
src/lru.c:195:33: warning: if statement has empty body [-Wempty-body]
if (elem->data && elem->free);
^
Both were introduced in 1.6-dev2 with commit f90ac55 ("MINOR: lru: Add the
possibility to free data when an item is removed"), so no backport is needed.
It lookup a key in a LRU cache for use with specified domain and revision. It
differs from lru64_get as it does not create missing keys. The function returns
NULL if an error or a cache miss occurs.
Now, When a item is committed in an LRU tree, you can define a function to free
data owned by this item. This function will be called when the item is removed
from the LRU tree or when the tree is destroyed..
This will be usable to implement some maps/acl caches for heavy datasets
loaded from files (mostly regex-based but in general anything that cannot
be indexed in a tree).
Baptiste Assmann
Christopher Faulet
Willy Tarreau