Import upstream v0.16.22, stripped

Upstream commit: 474dd0229cb20cf513036619781ed97bd8073c3f
Enterprise-only files removed or emptied: 63
Enterprise-only snippets removed: 117 in 50 files
Dangling module declarations removed: 5
Cargo edits turning enterprise off: 14
Verification: clean
Enterprise feature gates left for rebuilt features: 19 in 18 files

Produced by tools/fork/strip.py. The full report is in docs/fork/strip-reports/ on main.

crates/imap-proto/src/protocol/authenticate.rs

@@ -0,0 +1,53 @@
+/*
+ * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ */
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Arguments {
+    pub tag: String,
+    pub mechanism: Mechanism,
+    pub params: Vec<String>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Mechanism {
+    Plain,
+    CramMd5,
+    DigestMd5,
+    ScramSha1,
+    ScramSha256,
+    Apop,
+    Ntlm,
+    Gssapi,
+    Anonymous,
+    External,
+    OAuthBearer,
+    XOauth2,
+}
+
+impl Mechanism {
+    pub fn serialize(&self, buf: &mut Vec<u8>) {
+        buf.extend_from_slice(match self {
+            Mechanism::Plain => b"PLAIN",
+            Mechanism::CramMd5 => b"CRAM-MD5",
+            Mechanism::DigestMd5 => b"DIGEST-MD5",
+            Mechanism::ScramSha1 => b"SCRAM-SHA-1",
+            Mechanism::ScramSha256 => b"SCRAM-SHA-256",
+            Mechanism::Apop => b"APOP",
+            Mechanism::Ntlm => b"NTLM",
+            Mechanism::Gssapi => b"GSSAPI",
+            Mechanism::Anonymous => b"ANONYMOUS",
+            Mechanism::External => b"EXTERNAL",
+            Mechanism::OAuthBearer => b"OAUTHBEARER",
+            Mechanism::XOauth2 => b"XOAUTH2",
+        });
+    }
+
+    pub fn into_bytes(self) -> Vec<u8> {
+        let mut buf = Vec::with_capacity(10);
+        self.serialize(&mut buf);
+        buf
+    }
+}