Problem: pollers unnecessarily depend on whole ctx_t, but actually use only start_thread method

Solution: extract thread_ctx_t from ctx_t

src/ctx.cpp

@@ -76,9 +76,7 @@ zmq::ctx_t::ctx_t () :
     max_msgsz (INT_MAX),
     io_thread_count (ZMQ_IO_THREADS_DFLT),
     blocky (true),
-    ipv6 (false),
-    thread_priority (ZMQ_THREAD_PRIORITY_DFLT),
-    thread_sched_policy (ZMQ_THREAD_SCHED_POLICY_DFLT)
+    ipv6 (false)
 {
 #ifdef HAVE_FORK
     pid = getpid ();
@@ -241,29 +239,6 @@ int zmq::ctx_t::set (int option_, int optval_)
     } else if (option_ == ZMQ_IPV6 && optval_ >= 0) {
         scoped_lock_t locker (opt_sync);
         ipv6 = (optval_ != 0);
-    } else if (option_ == ZMQ_THREAD_PRIORITY && optval_ >= 0) {
-        scoped_lock_t locker (opt_sync);
-        thread_priority = optval_;
-    } else if (option_ == ZMQ_THREAD_SCHED_POLICY && optval_ >= 0) {
-        scoped_lock_t locker (opt_sync);
-        thread_sched_policy = optval_;
-    } else if (option_ == ZMQ_THREAD_AFFINITY_CPU_ADD && optval_ >= 0) {
-        scoped_lock_t locker (opt_sync);
-        thread_affinity_cpus.insert (optval_);
-    } else if (option_ == ZMQ_THREAD_AFFINITY_CPU_REMOVE && optval_ >= 0) {
-        scoped_lock_t locker (opt_sync);
-        std::set<int>::iterator it = thread_affinity_cpus.find (optval_);
-        if (it != thread_affinity_cpus.end ()) {
-            thread_affinity_cpus.erase (it);
-        } else {
-            errno = EINVAL;
-            rc = -1;
-        }
-    } else if (option_ == ZMQ_THREAD_NAME_PREFIX && optval_ >= 0) {
-        std::ostringstream s;
-        s << optval_;
-        scoped_lock_t locker (opt_sync);
-        thread_name_prefix = s.str ();
     } else if (option_ == ZMQ_BLOCKY && optval_ >= 0) {
         scoped_lock_t locker (opt_sync);
         blocky = (optval_ != 0);
@@ -271,8 +246,7 @@ int zmq::ctx_t::set (int option_, int optval_)
         scoped_lock_t locker (opt_sync);
         max_msgsz = optval_ < INT_MAX ? optval_ : INT_MAX;
     } else {
-        errno = EINVAL;
-        rc = -1;
+        rc = thread_ctx_t::set (option_, optval_);
     }
     return rc;
 }
@@ -434,9 +408,15 @@ zmq::object_t *zmq::ctx_t::get_reaper ()
     return reaper;
 }
 
-void zmq::ctx_t::start_thread (thread_t &thread_,
-                               thread_fn *tfn_,
-                               void *arg_) const
+zmq::thread_ctx_t::thread_ctx_t () :
+    thread_priority (ZMQ_THREAD_PRIORITY_DFLT),
+    thread_sched_policy (ZMQ_THREAD_SCHED_POLICY_DFLT)
+{
+}
+
+void zmq::thread_ctx_t::start_thread (thread_t &thread_,
+                                      thread_fn *tfn_,
+                                      void *arg_) const
 {
     static unsigned int nthreads_started = 0;
 
@@ -453,6 +433,39 @@ void zmq::ctx_t::start_thread (thread_t &thread_,
     nthreads_started++;
 }
 
+int zmq::thread_ctx_t::set (int option_, int optval_)
+{
+    int rc = 0;
+    if (option_ == ZMQ_THREAD_SCHED_POLICY && optval_ >= 0) {
+        scoped_lock_t locker (opt_sync);
+        thread_sched_policy = optval_;
+    } else if (option_ == ZMQ_THREAD_AFFINITY_CPU_ADD && optval_ >= 0) {
+        scoped_lock_t locker (opt_sync);
+        thread_affinity_cpus.insert (optval_);
+    } else if (option_ == ZMQ_THREAD_AFFINITY_CPU_REMOVE && optval_ >= 0) {
+        scoped_lock_t locker (opt_sync);
+        std::set<int>::iterator it = thread_affinity_cpus.find (optval_);
+        if (it != thread_affinity_cpus.end ()) {
+            thread_affinity_cpus.erase (it);
+        } else {
+            errno = EINVAL;
+            rc = -1;
+        }
+    } else if (option_ == ZMQ_THREAD_NAME_PREFIX && optval_ >= 0) {
+        std::ostringstream s;
+        s << optval_;
+        scoped_lock_t locker (opt_sync);
+        thread_name_prefix = s.str ();
+    } else if (option_ == ZMQ_THREAD_PRIORITY && optval_ >= 0) {
+        scoped_lock_t locker (opt_sync);
+        thread_priority = optval_;
+    } else {
+        errno = EINVAL;
+        rc = -1;
+    }
+    return rc;
+}
+
 void zmq::ctx_t::send_command (uint32_t tid_, const command_t &command_)
 {
     slots[tid_]->send (command_);

src/ctx.hpp

@@ -61,10 +61,32 @@ struct endpoint_t
     options_t options;
 };
 
+class thread_ctx_t
+{
+  public:
+    thread_ctx_t ();
+
+    //  Start a new thread with proper scheduling parameters.
+    void start_thread (thread_t &thread_, thread_fn *tfn_, void *arg_) const;
+
+    int set (int option_, int optval_);
+
+  protected:
+    //  Synchronisation of access to context options.
+    mutex_t opt_sync;
+
+  private:
+    //  Thread parameters.
+    int thread_priority;
+    int thread_sched_policy;
+    std::set<int> thread_affinity_cpus;
+    std::string thread_name_prefix;
+};
+
 //  Context object encapsulates all the global state associated with
 //  the library.
 
-class ctx_t
+class ctx_t : public thread_ctx_t
 {
   public:
     //  Create the context object.
@@ -96,9 +118,6 @@ class ctx_t
     zmq::socket_base_t *create_socket (int type_);
     void destroy_socket (zmq::socket_base_t *socket_);
 
-    //  Start a new thread with proper scheduling parameters.
-    void start_thread (thread_t &thread_, thread_fn *tfn_, void *arg_) const;
-
     //  Send command to the destination thread.
     void send_command (uint32_t tid_, const command_t &command_);
 
@@ -215,15 +234,6 @@ class ctx_t
     //  Is IPv6 enabled on this context?
     bool ipv6;
 
-    //  Thread parameters.
-    int thread_priority;
-    int thread_sched_policy;
-    std::set<int> thread_affinity_cpus;
-    std::string thread_name_prefix;
-
-    //  Synchronisation of access to context options.
-    mutex_t opt_sync;
-
     ctx_t (const ctx_t &);
     const ctx_t &operator= (const ctx_t &);
 

src/devpoll.cpp

@@ -46,7 +46,7 @@
 #include "config.hpp"
 #include "i_poll_events.hpp"
 
-zmq::devpoll_t::devpoll_t (const zmq::ctx_t &ctx_) :
+zmq::devpoll_t::devpoll_t (const zmq::thread_ctx_t &ctx_) :
     ctx (ctx_),
     stopping (false)
 {

src/devpoll.hpp

@@ -52,7 +52,7 @@ class devpoll_t : public poller_base_t
   public:
     typedef fd_t handle_t;
 
-    devpoll_t (const ctx_t &ctx_);
+    devpoll_t (const thread_ctx_t &ctx_);
     ~devpoll_t ();
 
     //  "poller" concept.
@@ -75,7 +75,7 @@ class devpoll_t : public poller_base_t
     void loop ();
 
     // Reference to ZMQ context.
-    const ctx_t &ctx;
+    const thread_ctx_t &ctx;
 
     //  File descriptor referring to "/dev/poll" pseudo-device.
     fd_t devpoll_fd;

src/epoll.cpp

@@ -44,7 +44,9 @@
 #include "config.hpp"
 #include "i_poll_events.hpp"
 
-zmq::epoll_t::epoll_t (const zmq::ctx_t &ctx_) : ctx (ctx_), stopping (false)
+zmq::epoll_t::epoll_t (const zmq::thread_ctx_t &ctx_) :
+    ctx (ctx_),
+    stopping (false)
 {
 #ifdef ZMQ_USE_EPOLL_CLOEXEC
     //  Setting this option result in sane behaviour when exec() functions

src/epoll.hpp

@@ -55,7 +55,7 @@ class epoll_t : public poller_base_t
   public:
     typedef void *handle_t;
 
-    epoll_t (const ctx_t &ctx_);
+    epoll_t (const thread_ctx_t &ctx_);
     ~epoll_t ();
 
     //  "poller" concept.
@@ -78,7 +78,7 @@ class epoll_t : public poller_base_t
     void loop ();
 
     // Reference to ZMQ context.
-    const ctx_t &ctx;
+    const thread_ctx_t &ctx;
 
     //  Main epoll file descriptor
     fd_t epoll_fd;

src/kqueue.cpp

@@ -54,7 +54,9 @@
 #define kevent_udata_t void *
 #endif
 
-zmq::kqueue_t::kqueue_t (const zmq::ctx_t &ctx_) : ctx (ctx_), stopping (false)
+zmq::kqueue_t::kqueue_t (const zmq::thread_ctx_t &ctx_) :
+    ctx (ctx_),
+    stopping (false)
 {
     //  Create event queue
     kqueue_fd = kqueue ();

src/kqueue.hpp

@@ -54,7 +54,7 @@ class kqueue_t : public poller_base_t
   public:
     typedef void *handle_t;
 
-    kqueue_t (const ctx_t &ctx_);
+    kqueue_t (const thread_ctx_t &ctx_);
     ~kqueue_t ();
 
     //  "poller" concept.
@@ -77,7 +77,7 @@ class kqueue_t : public poller_base_t
     void loop ();
 
     // Reference to ZMQ context.
-    const ctx_t &ctx;
+    const thread_ctx_t &ctx;
 
     //  File descriptor referring to the kernel event queue.
     fd_t kqueue_fd;

src/poll.cpp

@@ -43,7 +43,7 @@
 #include "config.hpp"
 #include "i_poll_events.hpp"
 
-zmq::poll_t::poll_t (const zmq::ctx_t &ctx_) :
+zmq::poll_t::poll_t (const zmq::thread_ctx_t &ctx_) :
     ctx (ctx_),
     retired (false),
     stopping (false)

src/poll.hpp

@@ -57,7 +57,7 @@ class poll_t : public poller_base_t
   public:
     typedef fd_t handle_t;
 
-    poll_t (const ctx_t &ctx_);
+    poll_t (const thread_ctx_t &ctx_);
     ~poll_t ();
 
     //  "poller" concept.
@@ -82,7 +82,7 @@ class poll_t : public poller_base_t
     void cleanup_retired();
 
     // Reference to ZMQ context.
-    const ctx_t &ctx;
+    const thread_ctx_t &ctx;
 
     struct fd_entry_t
     {

src/pollset.cpp

@@ -42,7 +42,7 @@
 #include "config.hpp"
 #include "i_poll_events.hpp"
 
-zmq::pollset_t::pollset_t (const zmq::ctx_t &ctx_) :
+zmq::pollset_t::pollset_t (const zmq::thread_ctx_t &ctx_) :
     ctx (ctx_),
     stopping (false)
 {

src/pollset.hpp

@@ -55,7 +55,7 @@ class pollset_t : public poller_base_t
   public:
     typedef void *handle_t;
 
-    pollset_t (const ctx_t &ctx_);
+    pollset_t (const thread_ctx_t &ctx_);
     ~pollset_t ();
 
     //  "poller" concept.
@@ -78,7 +78,7 @@ class pollset_t : public poller_base_t
     void loop ();
 
     // Reference to ZMQ context.
-    const ctx_t &ctx;
+    const thread_ctx_t &ctx;
 
     //  Main pollset file descriptor
     ::pollset_t pollset_fd;

src/select.cpp

@@ -49,7 +49,7 @@
 
 #include <algorithm>
 
-zmq::select_t::select_t (const zmq::ctx_t &ctx_) :
+zmq::select_t::select_t (const zmq::thread_ctx_t &ctx_) :
     ctx (ctx_),
 #if defined ZMQ_HAVE_WINDOWS
     //  Fine as long as map is not cleared.

src/select.hpp

@@ -63,7 +63,7 @@ class select_t : public poller_base_t
   public:
     typedef fd_t handle_t;
 
-    select_t (const ctx_t &ctx_);
+    select_t (const thread_ctx_t &ctx_);
     ~select_t ();
 
     //  "poller" concept.
@@ -86,7 +86,7 @@ class select_t : public poller_base_t
     void loop ();
 
     //  Reference to ZMQ context.
-    const ctx_t &ctx;
+    const thread_ctx_t &ctx;
 
     //  Internal state.
     struct fds_set_t