wsd: support polling on client thread

Previously SocketPoll expected to be
running its own thread for polling.
This is unnecessary when we have a
spare thread (e.g. main) that can
(and should, for efficiency) be used
for polling rather than starting
dedicated thread.

Not starting the SocketPoll's thread
and calling SocketPoll::poll() directly
worked, the warning logs on each activity
notwithstanding.

The warnings aren't just noisy, they are
a performance drain as well, and signal
that something is wrong. The new code
now makes the API cleaner and avoids
unnecessary warning logs, while being
faster.

Change-Id: Ibf9a223c59dae6522a5fc2e5d84a8ef191b577b1

1 files changed, 7 insertions, 1 deletions

diff --git a/net/Socket.cpp b/net/Socket.cpp
index 8acd98ba22..208efc3c9c 100644
--- a/net/Socket.cpp
+++ b/net/Socket.cpp
@@ -66,6 +66,7 @@ SocketPoll::SocketPoll(const std::string& threadName)
       _stop(false),
       _threadStarted(false),
       _threadFinished(false),
+      _runOnClientThread(false),
       _owner(std::this_thread::get_id())
 {
     // Create the wakeup fd.
@@ -109,8 +110,10 @@ SocketPoll::~SocketPoll()
     _wakeup[1] = -1;
 }
 
-void SocketPoll::startThread()
+bool SocketPoll::startThread()
 {
+    assert(!_runOnClientThread);
+
     if (!_threadStarted)
     {
         _threadStarted = true;
@@ -119,6 +122,7 @@ void SocketPoll::startThread()
         try
         {
             _thread = std::thread(&SocketPoll::pollingThreadEntry, this);
+            return true;
         }
         catch (const std::exception& exc)
         {
@@ -126,6 +130,8 @@ void SocketPoll::startThread()
             _threadStarted = false;
         }
     }
+
+    return false;
 }
 
 void SocketPoll::joinThread()