Move common code for IMAP and SMTP to login_param.rs

src/login_param.rs

@@ -251,6 +251,29 @@ fn get_readable_flags(flags: i32) -> String {
     res
 }
 
+pub fn dc_build_tls(
+    certificate_checks: CertificateChecks,
+) -> Result<native_tls::TlsConnector, native_tls::Error> {
+    let mut tls_builder = native_tls::TlsConnector::builder();
+    match certificate_checks {
+        CertificateChecks::Automatic => {
+            // Same as AcceptInvalidCertificates for now.
+            // TODO: use provider database when it becomes available
+            tls_builder
+                .danger_accept_invalid_hostnames(true)
+                .danger_accept_invalid_certs(true)
+        }
+        CertificateChecks::Strict => &mut tls_builder,
+        CertificateChecks::AcceptInvalidHostnames => {
+            tls_builder.danger_accept_invalid_hostnames(true)
+        }
+        CertificateChecks::AcceptInvalidCertificates => tls_builder
+            .danger_accept_invalid_hostnames(true)
+            .danger_accept_invalid_certs(true),
+    }
+    .build()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;