From 64120be7af8d2ded76cd3a3401fc69cadb96351e Mon Sep 17 00:00:00 2001
From: Pixel <pixel@nobis-crew.org>
Date: Tue, 29 Nov 2011 01:21:48 -0800
Subject: The TaskManager no longer waits on the pop(); instead it waits in the
 libev loop; also the Queue<> template changed for a naive but std-less
 implementation.

---
 includes/TaskMan.h |  2 +-
 includes/Threads.h | 44 +++++++++++++++++++++++++++++++-------------
 src/Socket.cc      |  2 +-
 src/TaskMan.cc     | 18 ++++++++++--------
 4 files changed, 43 insertions(+), 23 deletions(-)

diff --git a/includes/TaskMan.h b/includes/TaskMan.h
index 026ea88..1e7a2f1 100644
--- a/includes/TaskMan.h
+++ b/includes/TaskMan.h
@@ -51,7 +51,7 @@ class TaskMan {
     struct taskHasher { size_t operator()(const Task * t) const { return reinterpret_cast<uintptr_t>(t); } };
     typedef gnu::hash_set<Task *, taskHasher> taskHash_t;
     taskHash_t m_tasks, m_signaledTasks;
-    Queue<Task *> m_pendingAdd;
+    Queue<Task> m_pendingAdd;
     bool m_stopped;
     struct ev_loop * m_loop;
     bool m_allowedToSignal;
diff --git a/includes/Threads.h b/includes/Threads.h
index 256e8e3..ca60627 100644
--- a/includes/Threads.h
+++ b/includes/Threads.h
@@ -1,6 +1,5 @@
 #pragma once
 
-#include <queue>
 #include <pthread.h>
 
 namespace Balau {
@@ -40,33 +39,52 @@ class Thread {
 template<class T>
 class Queue {
   public:
-      Queue() { pthread_cond_init(&m_cond, NULL); }
-      ~Queue() { while (size()) pop(); pthread_cond_destroy(&m_cond); }
-    void push(T & t) {
+      Queue() : m_front(NULL), m_back(NULL) { pthread_cond_init(&m_cond, NULL); }
+      ~Queue() { while (!isEmpty()) pop(); pthread_cond_destroy(&m_cond); }
+    void push(T * t) {
         m_lock.enter();
-        m_queue.push(t);
+        Cell * c = new Cell(t);
+        c->m_prev = m_back;
+        if (m_back)
+            m_back->m_next = c;
+        else
+            m_front = c;
+        m_back = c;
         pthread_cond_signal(&m_cond);
         m_lock.leave();
     }
-    T pop() {
+    T * pop() {
         m_lock.enter();
-        if (m_queue.size() == 0)
+        while (!m_front)
             pthread_cond_wait(&m_cond, &m_lock.m_lock);
-        T t = m_queue.front();
-        m_queue.pop();
+        Cell * c = m_front;
+        m_front = c->m_next;
+        if (m_front)
+            m_front->m_prev = NULL;
+        else
+            m_back = NULL;
+        T * t = c->m_elem;
+        delete c;
         m_lock.leave();
         return t;
     }
-    int size() {
-        int r;
+    bool isEmpty() {
+        bool r;
         m_lock.enter();
-        r = m_queue.size();
+        r = !m_front;
         m_lock.leave();
         return r;
     }
   private:
-    std::queue<T> m_queue;
     Lock m_lock;
+    class Cell {
+      public:
+          Cell(T * elem) : m_next(NULL), m_prev(NULL), m_elem(elem) { }
+        Cell * m_next, * m_prev;
+        T * m_elem;
+    };
+    Cell * volatile m_front;
+    Cell * volatile m_back;
     pthread_cond_t m_cond;
 };
 
diff --git a/src/Socket.cc b/src/Socket.cc
index 3ca5494..af397a6 100644
--- a/src/Socket.cc
+++ b/src/Socket.cc
@@ -183,7 +183,7 @@ class ResolverThread : public Balau::Thread, public Balau::AtStart, public Balau
     virtual void * proc();
     virtual void doStart();
     virtual void doExit();
-    Balau::Queue<DNSRequest *> m_queue;
+    Balau::Queue<DNSRequest> m_queue;
 };
 
 void ResolverThread::doStart() {
diff --git a/src/TaskMan.cc b/src/TaskMan.cc
index 393eb57..28fb0e3 100644
--- a/src/TaskMan.cc
+++ b/src/TaskMan.cc
@@ -34,7 +34,7 @@ class TaskScheduler : public Thread, public AtStart, public AtExit {
     void unregisterTaskMan(TaskMan * t);
     void stopAll();
   private:
-    Queue<Task *> m_queue;
+    Queue<Task> m_queue;
     std::queue<TaskMan *> m_taskManagers;
     Lock m_lock;
     volatile bool m_stopping;
@@ -80,6 +80,7 @@ void Balau::TaskScheduler::stopAll() {
         m_taskManagers.pop();
         altQueue.push(tm);
         tm->addToPending(new Stopper());
+        tm->m_evt.send();
     }
     while (!altQueue.empty()) {
         tm = altQueue.front();
@@ -125,7 +126,9 @@ void Balau::TaskScheduler::doExit() {
     join();
 }
 
-void asyncDummy(ev::async & w, int revents) { }
+void asyncDummy(ev::async & w, int revents) {
+    Balau::Printer::elog(Balau::E_TASK, "TaskMan is getting woken up...");
+}
 
 Balau::TaskMan::TaskMan() : m_stopped(false), m_allowedToSignal(false) {
 #ifndef _WIN32
@@ -217,11 +220,8 @@ void Balau::TaskMan::mainLoop() {
                 noWait = true;
         }
 
-        // probably means we have pending tasks; or none at all, for some reason. Don't wait on it forever.
-        if (m_tasks.size() == 0)
-            noWait = true;
-
-        if (m_pendingAdd.size() != 0)
+        // if we begin that loop with any pending task, just don't loop, so we can add them immediately.
+        if (!m_pendingAdd.isEmpty())
             noWait = true;
 
         // libev's event "loop". We always runs it once though.
@@ -254,8 +254,10 @@ void Balau::TaskMan::mainLoop() {
         m_signaledTasks.clear();
 
         // Adding tasks that were added, maybe from other threads
-        while (((m_pendingAdd.size() != 0) || (m_tasks.size() == 0)) && !m_stopped) {
+        while (!m_pendingAdd.isEmpty()) {
+            Printer::elog(E_TASK, "TaskMan at %p trying to pop a task...", this);
             t = m_pendingAdd.pop();
+            Printer::elog(E_TASK, "TaskMan at %p popped task %p...", this, t);
             Assert(m_tasks.find(t) == m_tasks.end());
             ev_now_update(m_loop);
             t->setup(this, getStack());
-- 
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