imap: support setting $Forwarded

midb recognized a Forwarded flag (W), but this was never exposed via
midb_agent, and imap_parser.c never did anything with it either.
Implement it.

Fixes: gromox-0~666

Author: jengelh

doc/changelog.rst

@@ -7,6 +7,7 @@ Enhancements:
   (if not running grommunio nginx config in front)
 * oxcical: try to handle ICS files with missing VTIMEZONE blocks
 * oxcical: support YEARLY recurrences with BYDAY without BYSETPOS
+* imap: offer $Forwarded keyword for APPEND/STORE commands
 
 Fixes:
 
@@ -16,6 +17,8 @@ Fixes:
   exported to iCal
 * midb, imap: make EXPUNGE synchronous so that old UIDs don't reappear in
   a subsequent FETCH
+* midb: respect setting \Deleted, \Answered, \Flagged during APPEND
+
 
 
 Gromox 2.46 (2025-05-28)

include/gromox/midb.hpp

@@ -43,6 +43,7 @@ enum {
 };
 
 enum midb_flag : char {
+	/* On-wire text protocol */
 	answered = 'A',
 	deleted = 'D',
 	flagged = 'F',

include/gromox/midb_agent.hpp

@@ -20,6 +20,12 @@ enum {
 	FLAG_DELETED  = 0x8,
 	FLAG_SEEN     = 0x10,
 	FLAG_DRAFT    = 0x20,
+	FLAG_FORWARDED= 0x40,
+
+	/* mnemonics */
+	FLAG_ALL      = 0x4F,
+
+	/* internal */
 	FLAG_LOADED   = 0x80,
 };
 

mra/imap/cmd.cpp

@@ -450,6 +450,8 @@ static std::string icp_convert_flags_string(int flag_bits)
 		out += "\\Seen ";
 	if (flag_bits & FLAG_DRAFT)
 		out += "\\Draft ";
+	if (flag_bits & FLAG_FORWARDED)
+		out += "$Forwarded ";
 	if (out.size() > 1)
 		/* There is more than just the opening parenthesis, so there must be a space */
 		out.back() = ')';
@@ -956,8 +958,7 @@ static void icp_store_flags(const char *cmd, const std::string &mid,
 	if (0 == strcasecmp(cmd, "FLAGS") ||
 		0 == strcasecmp(cmd, "FLAGS.SILENT")) {
 		midb_agent::unset_flags(pcontext->maildir, pcontext->selected_folder,
-			mid, FLAG_ANSWERED | FLAG_FLAGGED | FLAG_DELETED |
-			FLAG_SEEN | FLAG_DRAFT | FLAG_RECENT, nullptr, &errnum);
+			mid, FLAG_ALL, nullptr, &errnum);
 		midb_agent::set_flags(pcontext->maildir, pcontext->selected_folder,
 			mid, flag_bits, nullptr, &errnum);
 		if (0 == strcasecmp(cmd, "FLAGS")) {
@@ -1129,14 +1130,15 @@ static void icp_convert_folderlist(std::vector<enum_folder_t> &pfile) try
 }
 
 static std::string flagbits_to_s(bool seen, bool answ, bool flagged, bool draft,
-    bool del)
+    bool del, bool fwd)
 {
 	std::string s = "(";
 	if (seen)    s += midb_flag::seen;
 	if (answ)    s += midb_flag::answered;
 	if (flagged) s += midb_flag::flagged;
 	if (draft)   s += midb_flag::unsent;
 	if (del)     s += midb_flag::deleted;
+	if (fwd)     s += midb_flag::forwarded;
 	s += ')';
 	return s;
 }
@@ -1513,12 +1515,12 @@ static int icp_selex(int argc, char **argv, imap_context &ctx, bool readonly) tr
 	auto buf = fmt::format(
 		"* {} EXISTS\r\n"
 		"* {} RECENT\r\n"
-		"* FLAGS (\\Answered \\Flagged \\Deleted \\Seen \\Draft)\r\n"
+		"* FLAGS (\\Answered \\Flagged \\Deleted \\Seen \\Draft $Forwarded)\r\n"
 		"* OK {}\r\n",
 		pcontext->contents.n_exists(),
 		pcontext->contents.n_recent, readonly ?
 		"[PERMANENTFLAGS ()] no permanent flags permitted" :
-		"[PERMANENTFLAGS (\\Answered \\Flagged \\Deleted \\Seen \\Draft)] limited");
+		"[PERMANENTFLAGS (\\Answered \\Flagged \\Deleted \\Seen \\Draft $Forwarded)] limited");
 	if (pcontext->contents.firstunseen != 0)
 		buf += fmt::format("* OK [UNSEEN {}] message {} is first unseen\r\n",
 			pcontext->contents.firstunseen,
@@ -2003,7 +2005,9 @@ int icp_append(int argc, char **argv, imap_context &ctx) try
 		            std::any_of(&temp_argv[0], &temp_argv[temp_argc],
 		            [](const char *s) { return strcasecmp(s, "\\Draft") == 0; }),
 		            std::any_of(&temp_argv[0], &temp_argv[temp_argc],
-		            [](const char *s) { return strcasecmp(s, "\\Deleted") == 0; }));
+		            [](const char *s) { return strcasecmp(s, "\\Deleted") == 0; }),
+		            std::any_of(&temp_argv[0], &temp_argv[temp_argc],
+		            [](const char *s) { return strcasecmp(s, "$Forwarded") == 0; }));
 	}
 	std::string mid_string;
 	time_t tmp_time = time(nullptr);
@@ -2066,7 +2070,7 @@ int icp_append(int argc, char **argv, imap_context &ctx) try
 
 static inline bool append_allowed_flag_name(const char *flag)
 {
-	static constexpr const char *names[] = {"\\Answered", "\\Flagged", "\\Seen", "\\Draft", "\\Deleted"};
+	static constexpr const char *names[] = {"\\Answered", "\\Flagged", "\\Seen", "\\Draft", "\\Deleted", "$Forwarded"};
 	for (auto s : names)
 		if (strcasecmp(flag, s) == 0)
 			return true;
@@ -2119,7 +2123,8 @@ static int icp_long_append_begin2(int argc, char **argv, imap_context &ctx) try
 	                    strcasestr(str_flags, "\\Answered") != nullptr,
 	                    strcasestr(str_flags, "\\Flagged") != nullptr,
 	                    strcasestr(str_flags, "\\Draft") != nullptr,
-	                    strcasestr(str_flags, "\\Deleted") != nullptr);
+	                    strcasestr(str_flags, "\\Deleted") != nullptr,
+	                    strcasestr(str_flags, "$Forwarded") != nullptr);
 	if (str_received == nullptr || *str_received == '\0' ||
 	    !icp_convert_imaptime(str_received, &ctx.append_time))
 		ctx.append_time = time(nullptr);
@@ -2498,6 +2503,8 @@ int icp_store(int argc, char **argv, imap_context &ctx)
 			flag_bits |= FLAG_DRAFT;
 		else if (strcasecmp(temp_argv[i], "\\Recent") == 0)
 			flag_bits |= FLAG_RECENT;			
+		else if (strcasecmp(temp_argv[i], "$Forwarded") == 0)
+			flag_bits |= FLAG_FORWARDED;
 		else
 			return 1807;
 	}
@@ -2759,6 +2766,8 @@ int icp_uid_store(int argc, char **argv, imap_context &ctx)
 			flag_bits |= FLAG_DRAFT;
 		else if (strcasecmp(temp_argv[i], "\\Recent") == 0)
 			flag_bits |= FLAG_RECENT;			
+		else if (strcasecmp(temp_argv[i], "$Forwarded") == 0)
+			flag_bits |= FLAG_FORWARDED;
 		else
 			return 1807;
 	}

mra/imap/parser.cpp

@@ -1343,6 +1343,11 @@ void imap_parser_echo_modify(imap_context *pcontext, STREAM *pstream)
 				buff[outlen++] = ' ';
 			outlen += gx_snprintf(&buff[outlen], std::size(buff) - outlen, "\\Draft");
 		}
+		if (flag_bits & FLAG_FORWARDED) {
+			if (b_first)
+				buff[outlen++] = ' ';
+			outlen += gx_snprintf(&buff[outlen], std::size(buff) - outlen, "$Forwarded");
+		}
 		outlen += gx_snprintf(&buff[outlen], std::size(buff) - outlen, "))\r\n");
 		if (pstream == nullptr)
 			pcontext->connection.write(buff, outlen);

mra/midb_agent.cpp

@@ -1091,6 +1091,7 @@ static unsigned int s_to_flagbits(std::string_view s)
 	if (s.find(midb_flag::deleted) != s.npos)  fl |= FLAG_DELETED;
 	if (s.find(midb_flag::seen) != s.npos)     fl |= FLAG_SEEN;
 	if (s.find(midb_flag::recent) != s.npos)   fl |= FLAG_RECENT;
+	if (s.find(midb_flag::forwarded) != s.npos)fl |= FLAG_FORWARDED;
 	return fl;
 }
 
@@ -1103,6 +1104,7 @@ static std::string flagbits_to_s(unsigned int v)
 	if (v & FLAG_DELETED)  s += midb_flag::deleted;
 	if (v & FLAG_SEEN)     s += midb_flag::seen;
 	if (v & FLAG_RECENT)   s += midb_flag::recent;
+	if (v & FLAG_FORWARDED)s += midb_flag::forwarded;
 	return s;
 }
 
@@ -1139,6 +1141,8 @@ static unsigned int di_to_flagbits(const Json::Value &jv)
 		fl |= FLAG_SEEN;
 	if (jv.isMember("recent") && (v = jv["recent"].asUInt()) != 0)
 		fl |= FLAG_RECENT;
+	if (jv.isMember("forwarded") && (v = jv["forwarded"].asUInt()) != 0)
+		fl |= FLAG_FORWARDED;
 	return fl;
 }