This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
This is similar to string_hash_ops but operates one file system paths
specifically. It will ensure that "/foo//bar" and "///foo/bar" are
considered to be the same path for hashmap purposes.
This makes use of the existing path_compare() API, and adds a matching
hashing function for it.
Note that relative and absolute paths will hash to different values,
however whether the path is suffixed with a slash or not is not
detected. This matches the existing path_compare() behaviour, and
follows the logic that on Linux there can't be two different objects at
path /foo/bar and /foo/bar/ either.
gcc5 spits out a warning about test-hashmap.c:
CC src/test/test-hashmap.o
src/test/test-hashmap.c: In function ‘test_string_compare_func’:
src/test/test-hashmap.c:76:79: warning: logical not is only applied to the left hand side of comparison [-Wlogical-not-parentheses]
This patch removes includes that are not used. The removals were found with
include-what-you-use which checks if any of the symbols from a header is
in use.
test-hashmap-ordered.c is generated from test-hashmap-plain.c simply by
substituting "ordered_hashmap" for "hashmap" etc.
In the cases where tests rely on the order of entries, a distinction
between plain and ordered hashmaps is made using the ORDERED macro,
which is defined only for test-hashmap-ordered.c.
The following hashmap_* and set_* functions/macros have never had any
users in systemd's history:
*_iterate_backwards
*_iterate_skip
*_last
*_FOREACH_BACKWARDS
Remove this dead code.
It is redundant to store 'hash' and 'compare' function pointers in
struct Hashmap separately. The functions always comprise a pair.
Store a single pointer to struct hash_ops instead.
systemd keeps hundreds of hashmaps, so this saves a little bit of
memory.
Instead of fixing the hashmap bucket array to 127 entries dynamically
size it, starting with a smaller one of 31. As soon as a fill level of
75% is reached, quadruple the size, and so on.
This should siginficantly optimize the lookup time in large tables
(from O(n) back to O(1)), and save memory on smaller tables (which most
are).
Zbigniew Jędrzejewski-Szmek