Generate message id for gmail.

generate_message_id_gmail.cpp

static std::string _generateMessageID(const char *sender, SIZE_T senderLength) {

	GUID pGuiId;
	WCHAR sGuiId[64] = { 0 };
	WCHAR sTrimId[64] = { 0 };
	std::string messageid;

	int strFromGuiSize = 0;
	char *senderCopy = 0;
	int domainSize = 50;
	char domain[50] = { 0 };
	char *context = 0;
	char *tmp = 0;
	char *sTrimIdA = 0;
	size_t messageIDSize = 0;
	char *messageID;

	//copy sender email
	if ((senderCopy = (char*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, senderLength + 1)) == NULL) {
		return "";
	}

	if (strncpy_s(senderCopy, senderLength + 1, sender, _TRUNCATE) != 0) {
		HeapFree(GetProcessHeap(), 0, senderCopy);
		senderCopy = NULL;
		return "";
	}

	//get first token
	if (helper::next_token(senderCopy, "@", &context) == NULL) {
		HeapFree(GetProcessHeap(), 0, senderCopy);
		senderCopy = NULL;
		return "";
	}

	//Get email domain
	if ((tmp = helper::next_token(NULL, "@", &context)) == NULL) {
		HeapFree(GetProcessHeap(), 0, senderCopy);
		senderCopy = NULL;
		return "";
	}

	if (strncpy_s(domain, domainSize, tmp, _TRUNCATE) != 0) {
		HeapFree(GetProcessHeap(), 0, senderCopy);
		senderCopy = NULL;
		return "";
	}

	HeapFree(GetProcessHeap(), 0, senderCopy);
	senderCopy = NULL;

	//Create a GUID, a unique 128-bit integer.
	if (CoCreateGuid(&pGuiId) != S_OK) {
		return "";
	}

	//Convert a globally unique identifier (GUID) into a string of printable characters.
	if ((strFromGuiSize = StringFromGUID2(pGuiId, sGuiId, _countof(sGuiId))) == 0) {
		return "";
	}

	//Remove { and } from generated GUID
	if (wmemmove_s(sTrimId, 64, sGuiId + 1, strFromGuiSize - 3) != 0) {
		return "";
	}

	sTrimId[strFromGuiSize - 3] = '\0';

	//Convert GUID to ascii
	sTrimIdA = helper::Wchar_To_Char(sTrimId, 64);
	if (sTrimIdA == NULL) {
		return "";
	}

	//messageID will store the final message-id value
	messageIDSize = strlen(sTrimIdA) + 1 + strlen(domain) + 1;

	if ((messageID = (char*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, messageIDSize)) == NULL) {
		HeapFree(GetProcessHeap(), 0, sTrimIdA);
		sTrimIdA = NULL;
		return "";
	}

	//copy trimmed guid to messageid e.g. xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
	if (_snprintf_s(messageID, messageIDSize, _TRUNCATE, "%s", sTrimIdA) == -1) {
		HeapFree(GetProcessHeap(), 0, sTrimIdA);
		sTrimIdA = NULL;
		HeapFree(GetProcessHeap(), 0, messageID);
		messageID = NULL;
		return "";
	}

	//concat @ e.g. xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx@
	if (_snprintf_s(messageID + strlen(sTrimIdA), messageIDSize - strlen(sTrimIdA), _TRUNCATE, "%s", "@") == -1) {
		HeapFree(GetProcessHeap(), 0, sTrimIdA);
		sTrimIdA = NULL;
		HeapFree(GetProcessHeap(), 0, messageID);
		messageID = NULL;
		return "";
	}

	//concat domain e.g. xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx@example.com
	if (_snprintf_s(messageID + strlen(sTrimIdA) + 1, messageIDSize - strlen(sTrimIdA) - 1, _TRUNCATE, "%s", domain) == -1) {
		HeapFree(GetProcessHeap(), 0, sTrimIdA);
		sTrimIdA = NULL;
		HeapFree(GetProcessHeap(), 0, messageID);
		messageID = NULL;
		return "";
	}

	HeapFree(GetProcessHeap(), 0, sTrimIdA);
	sTrimIdA = NULL;

	messageid = std::string(messageID);

	HeapFree(GetProcessHeap(), 0, messageID);
	messageID = NULL;

	return messageid;
}

static std::string _buildMessageID(const char *format, const char *from) {

	size_t _size = 0;
	char *result;
	std::string msgid;

	if ((msgid = _generateMessageID(from, strlen(from))) == "") {
		return "";
	}

	_size = strlen(format) + msgid.length();

	if ((result = (char*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, _size + 1)) == NULL) {
		return "";
	}

	if (_snprintf_s(result, _size + 1, _TRUNCATE, format, msgid.c_str()) == -1) {
		HeapFree(GetProcessHeap(), 0, result);
		result = NULL;
		return "";
	}

	msgid = std::string(result);

	HeapFree(GetProcessHeap(), 0, result);
	result = NULL;

	return msgid;
}