event/MultiSocketMonitor: eliminate virtual method CheckSockets()

Handle timeout internally.

src/event/MultiSocketMonitor.cxx

@@ -42,7 +42,8 @@ static GSourceFuncs multi_socket_monitor_source_funcs = {
 MultiSocketMonitor::MultiSocketMonitor(EventLoop &_loop)
 	:loop(_loop),
 	 source((Source *)g_source_new(&multi_socket_monitor_source_funcs,
-				       sizeof(*source))) {
+				       sizeof(*source))),
+	 absolute_timeout_us(G_MAXINT64) {
 	source->monitor = this;
 
 	g_source_attach(&source->base, loop.GetContext());
@@ -55,10 +56,21 @@ MultiSocketMonitor::~MultiSocketMonitor()
 	source = nullptr;
 }
 
+bool
+MultiSocketMonitor::Prepare(gint *timeout_r)
+{
+	int timeout_ms = *timeout_r = PrepareSockets();
+	absolute_timeout_us = timeout_ms < 0
+		? G_MAXINT64
+		: GetTime() + gint64(timeout_ms) * 1000;
+
+	return false;
+}
+
 bool
 MultiSocketMonitor::Check() const
 {
-	if (CheckSockets())
+	if (GetTime() >= absolute_timeout_us)
 		return true;
 
 	for (const auto &i : fds)

src/event/MultiSocketMonitor.hxx

@@ -52,6 +52,7 @@ class MultiSocketMonitor {
 
 	EventLoop &loop;
 	Source *source;
+	gint64 absolute_timeout_us;
 	std::forward_list<GPollFD> fds;
 
 public:
@@ -105,7 +106,6 @@ protected:
 	 * @return timeout [ms] or -1 for no timeout
 	 */
 	virtual int PrepareSockets() = 0;
-	virtual bool CheckSockets() const { return false; }
 	virtual void DispatchSockets() = 0;
 
 public:
@@ -116,11 +116,7 @@ public:
 				 gpointer user_data);
 
 private:
-	bool Prepare(gint *timeout_r) {
+	bool Prepare(gint *timeout_r);
-		*timeout_r = PrepareSockets();
-		return false;
-	}
-
 	bool Check() const;
 
 	void Dispatch() {

src/input/CurlInputPlugin.cxx

@@ -183,18 +183,6 @@ struct input_curl {
  * This class monitors all CURL file descriptors.
  */
 class CurlSockets final : private MultiSocketMonitor {
-	/**
-	 * Did CURL give us a timeout?  If yes, then we need to call
-	 * curl_multi_perform(), even if there was no event on any
-	 * file descriptor.
-	 */
-	bool have_timeout;
-
-	/**
-	 * The absolute time stamp when the timeout expires.
-	 */
-	gint64 absolute_timeout;
-
 public:
 	CurlSockets(EventLoop &_loop)
 		:MultiSocketMonitor(_loop) {}
@@ -205,7 +193,6 @@ private:
 	void UpdateSockets();
 
 	virtual int PrepareSockets() override;
-	virtual bool CheckSockets() const override;
 	virtual void DispatchSockets() override;
 };
 
@@ -541,14 +528,9 @@ CurlSockets::PrepareSockets()
 {
 	UpdateSockets();
 
-	have_timeout = false;
-
 	long timeout2;
 	CURLMcode mcode = curl_multi_timeout(curl.multi, &timeout2);
 	if (mcode == CURLM_OK) {
-		if (timeout2 >= 0)
-			absolute_timeout = GetTime() + timeout2 * 1000;
-
 		if (timeout2 >= 0 && timeout2 < 10)
 			/* CURL 7.21.1 likes to report "timeout=0",
 			   which means we're running in a busy loop.
@@ -556,7 +538,6 @@ CurlSockets::PrepareSockets()
 			   Let's use a lower limit of 10ms. */
 			timeout2 = 10;
 
-		have_timeout = timeout2 >= 0;
 		return timeout2;
 	} else {
 		g_warning("curl_multi_timeout() failed: %s\n",
@@ -565,15 +546,6 @@ CurlSockets::PrepareSockets()
 	}
 }
 
-bool
-CurlSockets::CheckSockets() const
-{
-	/* when a timeout has expired, we need to call
-	   curl_multi_perform(), even if there was no file descriptor
-	   event */
-	return have_timeout && GetTime() >= absolute_timeout;
-}
-
 void
 CurlSockets::DispatchSockets()
 {