From ebbf753626c9e5dd26743c379741c53f9f11866e Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 14 Sep 2016 13:51:56 +0300
Subject: [PATCH] Support asynchronous name resolution in Http::Client

---
 source/http/client.cpp | 89 +++++++++++++++++++++++++++++++++++-------
 source/http/client.h   | 17 ++++++++
 2 files changed, 92 insertions(+), 14 deletions(-)

diff --git a/source/http/client.cpp b/source/http/client.cpp
index 80815e0..6f22181 100644
--- a/source/http/client.cpp
+++ b/source/http/client.cpp
@@ -13,6 +13,9 @@ namespace Http {
 Client::Client():
 	sock(0),
 	event_disp(0),
+	resolver(0),
+	resolve_listener(0),
+	resolve_tag(0),
 	user_agent("libmsphttp/0.1"),
 	request(0),
 	response(0)
@@ -34,26 +37,26 @@ void Client::use_event_dispatcher(IO::EventDispatcher *ed)
 		event_disp->add(*sock);
 }
 
+void Client::use_resolver(Net::Resolver *r)
+{
+	if(resolver)
+	{
+		delete resolve_listener;
+		resolve_listener = 0;
+	}
+
+	resolver = r;
+	if(resolver)
+		resolve_listener = new ResolveListener(*this);
+}
+
 void Client::start_request(const Request &r)
 {
 	if(request)
 		throw client_busy();
 
-	string host = r.get_header("Host");
-	if(host.find(':')==string::npos)
-		host += ":80";
-	RefPtr<Net::SockAddr> addr = Net::resolve(host);
-
 	delete sock;
-	sock = new Net::StreamSocket(addr->get_family());
-	sock->set_block(false);
-
-	sock->signal_data_available.connect(sigc::mem_fun(this, &Client::data_available));
-	sock->signal_connect_finished.connect(sigc::mem_fun(this, &Client::connect_finished));
-	if(event_disp)
-		event_disp->add(*sock);
-
-	sock->connect(*addr);
+	sock = 0;
 
 	request = new Request(r);
 	if(!user_agent.empty())
@@ -62,6 +65,17 @@ void Client::start_request(const Request &r)
 	delete response;
 	response = 0;
 	in_buf.clear();
+
+	string host = r.get_header("Host");
+	if(host.find(':')==string::npos)
+		host += ":80";
+	if(resolver)
+		resolve_tag = resolver->resolve(host);
+	else
+	{
+		RefPtr<Net::SockAddr> addr = Net::resolve(host);
+		address_resolved(resolve_tag, *addr);
+	}
 }
 
 const Response *Client::get_url(const std::string &url)
@@ -104,6 +118,35 @@ void Client::abort()
 	request = 0;
 }
 
+void Client::address_resolved(unsigned tag, const Net::SockAddr &addr)
+{
+	if(tag!=resolve_tag)
+		return;
+	resolve_tag = 0;
+
+	sock = new Net::StreamSocket(addr.get_family());
+	sock->set_block(false);
+
+	sock->signal_data_available.connect(sigc::mem_fun(this, &Client::data_available));
+	sock->signal_connect_finished.connect(sigc::mem_fun(this, &Client::connect_finished));
+	if(event_disp)
+		event_disp->add(*sock);
+
+	sock->connect(addr);
+}
+
+void Client::resolve_failed(unsigned tag, const exception &err)
+{
+	if(tag!=resolve_tag)
+		return;
+	resolve_tag = 0;
+
+	signal_socket_error.emit(err);
+
+	delete request;
+	request = 0;
+}
+
 void Client::connect_finished(const exception *err)
 {
 	if(err)
@@ -159,5 +202,23 @@ void Client::data_available()
 	}
 }
 
+
+Client::ResolveListener::ResolveListener(Client &c):
+	client(c)
+{
+	client.resolver->signal_address_resolved.connect(sigc::mem_fun(this, &ResolveListener::address_resolved));
+	client.resolver->signal_resolve_failed.connect(sigc::mem_fun(this, &ResolveListener::resolve_failed));
+}
+
+void Client::ResolveListener::address_resolved(unsigned tag, const Net::SockAddr &addr)
+{
+	client.address_resolved(tag, addr);
+}
+
+void Client::ResolveListener::resolve_failed(unsigned tag, const exception &err)
+{
+	client.resolve_failed(tag, err);
+}
+
 } // namespace Http
 } // namespace Msp
diff --git a/source/http/client.h b/source/http/client.h
index 37acf0c..ebb7321 100644
--- a/source/http/client.h
+++ b/source/http/client.h
@@ -4,6 +4,7 @@
 #include <string>
 #include <sigc++/signal.h>
 #include <msp/io/eventdispatcher.h>
+#include <msp/net/resolve.h>
 #include <msp/net/streamsocket.h>
 
 namespace Msp {
@@ -26,8 +27,21 @@ public:
 	sigc::signal<void, const std::exception &> signal_socket_error;
 
 private:
+	struct ResolveListener: public sigc::trackable
+	{
+		Client &client;
+
+		ResolveListener(Client &);
+
+		void address_resolved(unsigned, const Net::SockAddr &);
+		void resolve_failed(unsigned, const std::exception &);
+	};
+
 	Net::StreamSocket *sock;
 	IO::EventDispatcher *event_disp;
+	Net::Resolver *resolver;
+	ResolveListener *resolve_listener;
+	unsigned resolve_tag;
 	std::string user_agent;
 	Request *request;
 	Response *response;
@@ -40,6 +54,7 @@ public:
 	~Client();
 
 	void use_event_dispatcher(IO::EventDispatcher *);
+	void use_resolver(Net::Resolver *);
 	void set_user_agent(const std::string &);
 	void start_request(const Request &);
 	const Response *get_url(const std::string &);
@@ -49,6 +64,8 @@ public:
 	const Request *get_request() const { return request; }
 	const Response *get_response() const { return response; }
 private:
+	void address_resolved(unsigned, const Net::SockAddr &);
+	void resolve_failed(unsigned, const std::exception &);
 	void connect_finished(const std::exception *);
 	void data_available();
 };
-- 
2.45.2