This merge request resolves some performance regressions introduced
with the change from isc_symtab_t to isc_hashmap_t.
The key improvements are:
1. Using a faster hash function than both isc_hashmap_t and
isc_symtab_t. The previous implementation used SipHash, but the
hashflood resistance properties of SipHash are unneeded for config
parsing.
2. Shrinking the initial size of the isc_hashmap_t used inside
isc_symtab_t. Symtab is mainly used for config parsing, and the
when used that way it will have between 1 and ~50 keys, but the
previous implementation initialized a map with 128 slots.
By initializing a smaller map, we speed up mallocs and optimize for
the typical case of few config keys.
3. Slight optimization of the string matching in the hashmap, so that
the tail is handled in a single load + comparison, instead of byte
by byte.
Of the three improvements, this is the least important.
This commit does several changes to isc_symtab:
1. Rewrite the isc_symtab to internally use isc_hashmap instead of
hand-stiched hashtable.
2. Create a new isc_symtab_define_and_return() api, which returns
the already defined symvalue on ISC_R_EXISTS; this allows users
of the API to skip the isc_symtab_lookup()+isc_symtab_define()
calls and directly call isc_symtab_define_and_return().
3. Merge isccc_symtab into isc_symtab - the only missing function
was isccc_symtab_foreach() that was merged into isc_symtab API.
4. Add full set of unit tests for the isc_symtab API.
the isc_mem allocation functions can no longer fail; as a result,
ISC_R_NOMEMORY is now rarely used: only when an external library
such as libjson-c or libfstrm could return NULL. (even in
these cases, arguably we should assert rather than returning
ISC_R_NOMEMORY.)
code and comments that mentioned ISC_R_NOMEMORY have been
cleaned up, and the following functions have been changed to
type void, since (in most cases) the only value they could
return was ISC_R_SUCCESS:
- dns_dns64_create()
- dns_dyndb_create()
- dns_ipkeylist_resize()
- dns_kasp_create()
- dns_kasp_key_create()
- dns_keystore_create()
- dns_order_create()
- dns_order_add()
- dns_peerlist_new()
- dns_tkeyctx_create()
- dns_view_create()
- dns_zone_setorigin()
- dns_zone_setfile()
- dns_zone_setstream()
- dns_zone_getdbtype()
- dns_zone_setjournal()
- dns_zone_setkeydirectory()
- isc_lex_openstream()
- isc_portset_create()
- isc_symtab_create()
(the exception is dns_view_create(), which could have returned
other error codes in the event of a crypto library failure when
calling isc_file_sanitize(), but that should be a RUNTIME_CHECK
anyway.)
There were a number of places that had copies of various ASCII
tables (case conversion, hex and decimal conversion) that are intended
to be faster than the ctype.h macros, or avoid locale pollution.
Move them into libisc, and wrap the lookup tables with macros that
avoid the ctype.h gotchas.
Historically, the inline keyword was a strong suggestion to the compiler
that it should inline the function marked inline. As compilers became
better at optimising, this functionality has receded, and using inline
as a suggestion to inline a function is obsolete. The compiler will
happily ignore it and inline something else entirely if it finds that's
a better optimisation.
Therefore, remove all the occurences of the inline keyword with static
functions inside single compilation unit and leave the decision whether
to inline a function or not entirely on the compiler
NOTE: We keep the usage the inline keyword when the purpose is to change
the linkage behaviour.
This commit converts the license handling to adhere to the REUSE
specification. It specifically:
1. Adds used licnses to LICENSES/ directory
2. Add "isc" template for adding the copyright boilerplate
3. Changes all source files to include copyright and SPDX license
header, this includes all the C sources, documentation, zone files,
configuration files. There are notes in the doc/dev/copyrights file
on how to add correct headers to the new files.
4. Handle the rest that can't be modified via .reuse/dep5 file. The
binary (or otherwise unmodifiable) files could have license places
next to them in <foo>.license file, but this would lead to cluttered
repository and most of the files handled in the .reuse/dep5 file are
system test files.
Also disable the semantic patch as the code needs tweaks here and there because
some destroy functions might not destroy the object and return early if the
object is still in use.
Mostly, several functions that take pointers as arguments, almost
always char * pointers, had those pointers qualified with "const".
Those that returned pointers to previously const-qualified arguments
had their return values qualified as const. Some structure members
were qualified as const to retain that attribute from the variables
from which they were assigned.
The macro DE_CONST was added to isc/util.h to deal with a handful of very
special places where something is qualified as const but really needs to have
its const qualifier removed.
Also cleaned up a few places where variable names clashed with reserved
identifiers. (Which mostly works fine, but strictly speaking is undefined
by the standard.)
Minor other ISC style cleanups.
Cleanup of redundant/useless header file inclusion.
ISC style lint, primarily for function declarations and standalone
comments -- ie, those that appear on a line without any code, which
should be written as follows:
/*
* This is a comment.
*/
