LibIMAP: Support for CAPABILITY command & response

This involves parsing messages with untagged responses

Userland/Libraries/LibIMAP/Client.cpp

@@ -112,6 +112,8 @@ static ReadonlyBytes command_byte_buffer(CommandType command)
     switch (command) {
     case CommandType::Noop:
         return "NOOP"sv.bytes();
+    case CommandType::Capability:
+        return "CAPABILITY"sv.bytes();
     }
     VERIFY_NOT_REACHED();
 }

Userland/Libraries/LibIMAP/Objects.h

@@ -17,10 +17,12 @@
 
 namespace IMAP {
 enum class CommandType {
+    Capability,
     Noop,
 };
 
 enum class ResponseType : unsigned {
+    Capability = 1u << 0,
 };
 
 class Parser;
@@ -65,8 +67,22 @@ public:
         m_response_type = m_response_type | static_cast<unsigned>(response_type);
     }
 
+    void add_capabilities(Vector<String>&& capabilities)
+    {
+        m_capabilities = move(capabilities);
+        add_response_type(ResponseType::Capability);
+    }
+
+    Vector<String>& capabilities()
+    {
+        VERIFY(contains_response_type(ResponseType::Capability));
+        return m_capabilities;
+    }
+
 private:
     unsigned m_response_type;
+
+    Vector<String> m_capabilities;
 };
 
 class SolidResponse {

Userland/Libraries/LibIMAP/Parser.cpp

@@ -27,6 +27,10 @@ ParseStatus Parser::parse(ByteBuffer&& buffer, bool expecting_tag)
         return { true, { ContinueRequest { data } } };
     }
 
+    while (try_consume("*")) {
+        parse_untagged();
+    }
+
     if (expecting_tag) {
         if (at_end()) {
             m_incomplete = true;
@@ -117,6 +121,30 @@ unsigned Parser::parse_number()
     return number.value();
 }
 
+void Parser::parse_untagged()
+{
+    consume(" ");
+
+    if (try_consume("CAPABILITY")) {
+        parse_capability_response();
+    } else {
+        auto x = parse_while([](u8 x) { return x != '\r'; });
+        consume("\r\n");
+        dbgln("ignored {}", x);
+    }
+}
+
+void Parser::parse_capability_response()
+{
+    auto capability = AK::Vector<String>();
+    while (!try_consume("\r\n")) {
+        consume(" ");
+        auto x = String(parse_atom());
+        capability.append(x);
+    }
+    m_response.data().add_capabilities(move(capability));
+}
+
 StringView Parser::parse_atom()
 {
     auto is_non_atom_char = [](u8 x) {

Userland/Libraries/LibIMAP/Parser.h

@@ -32,13 +32,22 @@ private:
 
     bool try_consume(StringView);
     bool at_end() { return position >= m_buffer.size(); };
+
     void parse_response_done();
+
     void consume(StringView x);
+
     unsigned parse_number();
     Optional<unsigned> try_parse_number();
+
     void parse_untagged();
+
     StringView parse_atom();
+
     ResponseStatus parse_status();
+
     StringView parse_while(Function<bool(u8)> should_consume);
+
+    void parse_capability_response();
 };
 }