core: replace the Condition class with a nicer Queue object that is

implemented using a cond_var on Linux, but will use something else on
Windows.

src/thread/thread.h

@@ -31,10 +31,10 @@ public:
     Mutex() : MutexBase() {}
 };
 
-class Condition : public ConditionBase
+class Queue : public QueueBase
 {
 public:
-    Condition() : ConditionBase() {}
+    Queue() : QueueBase() {}
 };
 
 class Thread : ThreadBase

src/thread/threadbase.h

@@ -17,6 +17,7 @@
 #define __LOL_THREADBASE_H__
 
 #if defined __linux__ || defined __native_client__
+#   include <cstring>
 #   include <pthread.h>
 #elif defined _WIN32
 #   include <windows.h>
@@ -74,18 +75,21 @@ private:
 #endif
 };
 
-class ConditionBase
+class QueueBase
 {
 public:
-    ConditionBase()
+    QueueBase()
     {
 #if defined __linux__ || defined __native_client__
+        memset(m_values, 0, sizeof(m_values));
+        m_waiting = 0;
+        m_size = 0;
         pthread_mutex_init(&m_mutex, NULL);
         pthread_cond_init(&m_cond, NULL);
 #endif
     }
 
-    ~ConditionBase()
+    ~QueueBase()
     {
 #if defined __linux__ || defined __native_client__
         pthread_cond_destroy(&m_cond);
@@ -93,36 +97,43 @@ public:
 #endif
     }
 
-    void Acquire()
+    void Push(int value)
     {
 #if defined __linux__ || defined __native_client__
         pthread_mutex_lock(&m_mutex);
-#endif
-    }
-
-    void Release()
-    {
-#if defined __linux__ || defined __native_client__
+        m_values[m_size] = value;
+        m_size++;
+        if (m_waiting)
+            pthread_cond_signal(&m_cond);
         pthread_mutex_unlock(&m_mutex);
 #endif
     }
 
-    void Wait()
-    {
-#if defined __linux__ || defined __native_client__
-        pthread_cond_wait(&m_cond, &m_mutex);
-#endif
-    }
-
-    void Notify()
+    int Pop()
     {
 #if defined __linux__ || defined __native_client__
-        pthread_cond_signal(&m_cond);
+        pthread_mutex_lock(&m_mutex);
+        /* Loop until there is something in the queue. Be careful, we
+         * could get woken up but another thread may have eaten the
+         * message in the meantime. */
+        while (!m_size)
+        {
+            m_waiting++;
+            pthread_cond_wait(&m_cond, &m_mutex);
+            m_waiting--;
+        }
+        m_size--;
+        int ret = m_values[0];
+        memmove(m_values, m_values + 1, m_size * sizeof(m_values[0]));
+        pthread_mutex_unlock(&m_mutex);
+        return ret;
 #endif
     }
 
 private:
 #if defined __linux__ || defined __native_client__
+    int m_values[100];
+    size_t m_waiting, m_size;
     pthread_mutex_t m_mutex;
     pthread_cond_t m_cond;
 #endif
@@ -134,9 +145,14 @@ public:
     ThreadBase(void *(*fn)(void *), void *data)
     {
 #if defined __linux__ || defined __native_client__
-        pthread_create(&m_thread, NULL, fn, data);
+        /* Set the joinable attribute for systems who don't play nice */
+        pthread_attr_t attr;
+        pthread_attr_init(&attr);
+        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
+        pthread_create(&m_thread, &attr, fn, data);
 #elif defined _WIN32
-        m_thread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)fn, data, 0, &m_tid);
+        m_thread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)fn,
+                                data, 0, &m_tid);
 #endif
     }