(evcom) Add fix for pausing against big buffers.

discussion:
http://groups.google.com/group/nodejs/browse_thread/thread/11a920da4d0ed21d

deps/evcom/evcom.c

@@ -853,7 +853,7 @@ on_io_event(EV_P_ ev_io *watcher, int revents)
 
   while (have_read_event || have_write_event) {
     /* RECV LOOP - TRY TO CLEAR THE BUFFER */
-    if (stream->read_action == NULL) {
+    if (stream->read_action == NULL || !ev_is_active(&stream->read_watcher)) {
       have_read_event = FALSE;
     } else {
       r = stream->read_action(stream);
@@ -866,7 +866,7 @@ on_io_event(EV_P_ ev_io *watcher, int revents)
     }
 
     /* SEND LOOP - TRY TO CLEAR THE BUFFER */
-    if (stream->write_action == NULL) {
+    if (stream->write_action == NULL || !ev_is_active(&stream->write_watcher)) {
       have_write_event = FALSE;
     } else {
       r = stream->write_action(stream);

test/mjsunit/test-tcp-throttle-kernel-buffer.js

@@ -0,0 +1,57 @@
+include("mjsunit.js");
+PORT = 20444;
+N = 30*1024; // 500kb
+
+puts("build big string");
+var body = "";
+for (var i = 0; i < N; i++) {
+  body += "C";
+}
+
+puts("start server on port " + PORT);
+
+server = node.tcp.createServer(function (connection) {
+  connection.addListener("connect", function () {
+    connection.send(body);
+    connection.fullClose();
+  });
+});
+server.listen(PORT);
+
+
+chars_recved = 0;
+npauses = 0;
+
+
+function onLoad () {
+  var paused = false;
+  client = node.tcp.createConnection(PORT);
+  client.setEncoding("ascii");
+  client.addListener("receive", function (d) {
+    chars_recved += d.length;
+    puts("got " + chars_recved);
+    if (!paused) {
+      client.readPause();
+      npauses += 1;
+      paused = true;
+      puts("pause");
+      x = chars_recved;
+      setTimeout(function () {
+        assertEquals(chars_recved, x);
+        client.readResume();
+        puts("resume");
+        paused = false;
+      }, 100);
+    }
+  });
+
+  client.addListener("eof", function () {
+    server.close();
+    client.close();
+  });
+}
+
+function onExit () {
+  assertEquals(N, chars_recved);
+  assertTrue(npauses > 2);
+}

test/mjsunit/test-tcp-throttle.js

@@ -31,15 +31,31 @@ function onLoad () {
 
   setTimeout(function () {
     chars_recved = recv.length; 
-    puts("chars_recved: " + chars_recved);
+    puts("pause at: " + chars_recved);
     assertTrue(chars_recved > 1);
     client.readPause();
     setTimeout(function () {
-      puts("chars_recved: " + chars_recved);
+      puts("resume at: " + chars_recved);
       assertEquals(chars_recved, recv.length);
       client.readResume();
+
+      setTimeout(function () {
+        chars_recved = recv.length; 
+        puts("pause at: " + chars_recved);
+        client.readPause();
+
+        setTimeout(function () {
+          puts("resume at: " + chars_recved);
+          assertEquals(chars_recved, recv.length);
+          client.readResume();
+
+        }, 500);
+
+      }, 500);
+
     }, 500);
-  }, 100);
+
+  }, 500);
 
   client.addListener("eof", function () {
     server.close();