This provides a clear and consistent interface for selecting TLS-related
features on both (xmpp and tokio-xmpp) crates. All feature checks have
been revamped. All working combinations have been tested (including a
connectivity test + --all-features docs build) using:
```
set -xeuo pipefail
features=(aws_lc_rs ring ktls,aws_lc_rs ktls,ring aws_lc_rs,ring aws_lc_rs,ring,ktls native-tls rustls-any-backend)
export RUSTFLAGS=" -D warnings"
cargo test --no-default-features
cargo test
for feature in ${features[@]}; do
echo ">>> BUILDING with $feature" 2>&1
# Running code or building examples cannot succeed with rustls-any-backend.
features="starttls,$feature"
if [ "$feature" != 'rustls-any-backend' ]; then
if ! cargo test --no-default-features --features="$features"; then
echo ">>> BUILD FAILED for tls feature set: $features" >&2
exit 1
fi
set +e
timeout -sINT -p -k 2 3 cargo run --no-default-features --features="$features" --example keep_connection -- test@hub.sotecware.net "$(pass xmpp/test@hub.sotecware.net)"
status="$?"
set -e
if [ $status -ne 0 ]; then
echo ">>> keep_connection did not shut down cleanly! (status: $status)" >&2
exit 1
fi
else
if ! cargo build --no-default-features --features="$feature"; then
echo ">>> BUILD FAILED for tls feature set: $features" >&2
exit 1
fi
fi
done
RUSTDOCFLAGS="--cfg docsrs" RUSTFLAGS="--cfg xmpprs_doc_build" cargo +nightly doc -Zrustdoc-map --all-features
```
The user may have to call some global rustls functions depending on the
exact feature set of rustls enabled. Hence, we have to expose it.
Concretely, if the user somehow ends up with more than one rustls
backend, they have to configure one of the backends as default backend
at startup.
If the user enables the tls-rust feature and forgets to disable
default-features (which includes tls-native), tell them and bail out.
The code was made to work anyway when both are enabled, and here it
defaults to tls-native. It does seem better to have one explicitely
choose one though hence the compile_error! message.
Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>
Without it, it seems impossible to start TLS on an XMPPStream object,
preventing any use of that object on its own (not wrapped into
AsyncClient or somesuch).
