Michael Weghorn 9a6e099f43 gdbsupport: allow to specify dependencies between observers ... Previously, the observers attached to an observable were always notified in the order in which they had been attached. That order is not easily controlled, because observers are typically attached in _initialize_* functions, which are called in an undefined order. However, an observer may require that another observer attached only later is called before itself is. Therefore, extend the 'observable' class to allow explicitly specifying dependencies when attaching observers, by adding the possibility to specify tokens for observers that it depends on. To make sure dependencies are notified before observers depending on them, the vector holding the observers is sorted in a way that dependencies come before observers depending on them. The current implementation for sorting uses the depth-first search algorithm for topological sorting as described at [1]. Extend the observable unit tests to cover this case as well. Check that this works for a few different orders in which the observers are attached. This newly introduced mechanism to explicitly specify dependencies will be used in a follow-up commit. [1] https://en.wikipedia.org/wiki/Topological_sorting#Depth-first_search Tested on x86_64-linux (Debian testing). gdb/ChangeLog: * unittests/observable-selftests.c (dependency_test_counters): New. (observer_token0, observer_token1, observer_token2, observer_token3, observer_token4, observer_token5): New. (struct dependency_observer_data): New struct. (observer_dependency_test_callback): New function. (test_observers): New. (run_dependency_test): New function. (test_dependency): New. (_initialize_observer_selftest): Register dependency test. gdbsupport/ChangeLog: * observable.h (class observable): Extend to allow specifying dependencies between observers, keep vector holding observers sorted so that dependencies are notified before observers depending on them. Change-Id: I5399def1eeb69ca99e28c9f1fdf321d78b530bdb		2021-04-27 11:22:32 -04:00
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basic_string_view
optional
array-view-selftests.c
child-path-selftests.c
cli-utils-selftests.c
command-def-selftests.c
common-utils-selftests.c
copy_bitwise-selftests.c
enum-flags-selftests.c
environ-selftests.c
filtered_iterator-selftests.c
format_pieces-selftests.c
function-view-selftests.c
gdb_tilde_expand-selftests.c
gmp-utils-selftests.c
lookup_name_info-selftests.c
main-thread-selftests.c
memory-map-selftests.c
memrange-selftests.c
mkdir-recursive-selftests.c
observable-selftests.c
offset-type-selftests.c
optional-selftests.c
parse-connection-spec-selftests.c
ptid-selftests.c
rsp-low-selftests.c
scoped_fd-selftests.c
scoped_mmap-selftests.c
scoped_restore-selftests.c
search-memory-selftests.c
string_view-selftests.c
style-selftests.c
tracepoint-selftests.c
tui-selftests.c
unpack-selftests.c
utils-selftests.c
vec-utils-selftests.c
xml-utils-selftests.c