8 files changed, 138 insertions, 5 deletions

diff --git a/src/rt/sync/condition_variable.cpp b/src/rt/sync/condition_variable.cpp
index d4032572..c34ab7f4 100644
--- a/src/rt/sync/condition_variable.cpp
+++ b/src/rt/sync/condition_variable.cpp
@@ -9,14 +9,16 @@
 
 // #define TRACE
 
-condition_variable::condition_variable() {
 #if defined(__WIN32__)
+condition_variable::condition_variable() {
     _event = CreateEvent(NULL, FALSE, FALSE, NULL);
+}
 #else
+condition_variable::condition_variable() {
     pthread_cond_init(&_cond, NULL);
     pthread_mutex_init(&_mutex, NULL);
-#endif
 }
+#endif
 
 condition_variable::~condition_variable() {
 #if defined(__WIN32__)
@@ -31,15 +33,31 @@ condition_variable::~condition_variable() {
  * Wait indefinitely until condition is signaled.
  */
 void condition_variable::wait() {
+    timed_wait(0);
+}
+
+void condition_variable::timed_wait(size_t timeout_in_ns) {
 #ifdef TRACE
-    printf("waiting on condition_variable: 0x%" PRIxPTR "\n",
-           (uintptr_t)this);
+    printf("waiting on condition_variable: 0x%" PRIxPTR " for %d ns. \n",
+           (uintptr_t) this, (int) timeout_in_ns);
 #endif
 #if defined(__WIN32__)
     WaitForSingleObject(_event, INFINITE);
 #else
     pthread_mutex_lock(&_mutex);
-    pthread_cond_wait(&_cond, &_mutex);
+    // wait() automatically releases the mutex while it waits, and acquires
+    // it right before exiting. This allows signal() to acquire the mutex
+    // when signaling.)
+    if (timeout_in_ns == 0) {
+        pthread_cond_wait(&_cond, &_mutex);
+    } else {
+        timeval time_val;
+        gettimeofday(&time_val, NULL);
+        timespec time_spec;
+        time_spec.tv_sec = time_val.tv_sec + 0;
+        time_spec.tv_nsec = time_val.tv_usec * 1000 + timeout_in_ns;
+        pthread_cond_timedwait(&_cond, &_mutex, &time_spec);
+    }
     pthread_mutex_unlock(&_mutex);
 #endif
 #ifdef TRACE
diff --git a/src/rt/sync/condition_variable.h b/src/rt/sync/condition_variable.h
index f847ef99..f336a7f2 100644
--- a/src/rt/sync/condition_variable.h
+++ b/src/rt/sync/condition_variable.h
@@ -13,6 +13,7 @@ public:
     virtual ~condition_variable();
 
     void wait();
+    void timed_wait(size_t timeout_in_ns);
     void signal();
 };
 
diff --git a/src/rt/sync/lock_free_queue.cpp b/src/rt/sync/lock_free_queue.cpp
index 69241ece..3f859862 100644
--- a/src/rt/sync/lock_free_queue.cpp
+++ b/src/rt/sync/lock_free_queue.cpp
@@ -18,6 +18,7 @@ lock_free_queue::lock_free_queue() : _tail(this) {
 
 void
 lock_free_queue::enqueue(lock_free_queue_node *item) {
+    lock.lock();
     item->next = (lock_free_queue_node *) NULL;
     lock_free_queue_node *last = _tail;
     _tail = item;
@@ -25,10 +26,12 @@ lock_free_queue::enqueue(lock_free_queue_node *item) {
         last = last->next;
     }
     last->next = item;
+    lock.unlock();
 }
 
 lock_free_queue_node *
 lock_free_queue::dequeue() {
+    lock.lock();
     lock_free_queue_node *item = next;
     if (item && !(next = item->next)) {
         _tail = (lock_free_queue_node *) this;
@@ -41,6 +44,7 @@ lock_free_queue::dequeue() {
             } while ((lost = help) != (lock_free_queue_node *) NULL);
         }
     }
+    lock.unlock();
     return item;
 }
 
diff --git a/src/rt/sync/lock_free_queue.h b/src/rt/sync/lock_free_queue.h
index 1f09ec52..c1a309b8 100644
--- a/src/rt/sync/lock_free_queue.h
+++ b/src/rt/sync/lock_free_queue.h
@@ -1,6 +1,8 @@
 #ifndef LOCK_FREE_QUEUE_H
 #define LOCK_FREE_QUEUE_H
 
+#include "spin_lock.h"
+
 class lock_free_queue_node {
 public:
     lock_free_queue_node *next;
@@ -8,6 +10,7 @@ public:
 };
 
 class lock_free_queue : lock_free_queue_node {
+    spin_lock lock;
     lock_free_queue_node *_tail;
 public:
     lock_free_queue();
diff --git a/src/rt/sync/sync.cpp b/src/rt/sync/sync.cpp
new file mode 100644
index 00000000..09a6f291
--- /dev/null
+++ b/src/rt/sync/sync.cpp
@@ -0,0 +1,12 @@
+#include "../globals.h"
+#include "sync.h"
+
+void sync::yield() {
+#ifdef __APPLE__
+    pthread_yield_np();
+#elif __WIN32__
+    Sleep(1);
+#else
+    pthread_yield();
+#endif
+}
diff --git a/src/rt/sync/sync.h b/src/rt/sync/sync.h
new file mode 100644
index 00000000..902b5661
--- /dev/null
+++ b/src/rt/sync/sync.h
@@ -0,0 +1,9 @@
+#ifndef SYNC_H
+#define SYNC_H
+
+class sync {
+public:
+    static void yield();
+};
+
+#endif /* SYNC_H */
diff --git a/src/rt/sync/timer.cpp b/src/rt/sync/timer.cpp
new file mode 100644
index 00000000..0487b397
--- /dev/null
+++ b/src/rt/sync/timer.cpp
@@ -0,0 +1,61 @@
+#include "../globals.h"
+#include "timer.h"
+
+#if defined(__APPLE__)
+#include <mach/mach_time.h>
+#endif
+
+timer::timer() {
+#if __WIN32__
+    uint64_t ticks_per_second;
+    QueryPerformanceFrequency((LARGE_INTEGER *)&ticks_per_second);
+    _ticks_per_us = ticks_per_second / 1000000;
+#endif
+    reset(0);
+}
+
+void
+timer::reset(uint64_t timeout) {
+    _start = get_time();
+    _timeout = timeout;
+}
+
+uint64_t
+timer::get_elapsed_time() {
+    return get_time() - _start;
+}
+
+int64_t
+timer::get_timeout() {
+    return _timeout - get_elapsed_time();
+}
+
+bool
+timer::has_timed_out() {
+    return get_timeout() <= 0;
+}
+
+uint64_t
+timer::get_time() {
+#ifdef __APPLE__
+    uint64_t time = mach_absolute_time();
+    mach_timebase_info_data_t info = {0, 0};
+    if (info.denom == 0) {
+        mach_timebase_info(&info);
+    }
+    uint64_t time_nano = time * (info.numer / info.denom);
+    return time_nano / 1000;
+#elif __WIN32__
+    uint64_t ticks;
+    QueryPerformanceCounter((LARGE_INTEGER *)&ticks);
+    return ticks / _ticks_per_us;
+#else
+    timespec ts;
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+    return (ts.tv_sec * 1000000000LL + ts.tv_nsec) / 1000;
+#endif
+}
+
+timer::~timer() {
+    // Nop.
+}
diff --git a/src/rt/sync/timer.h b/src/rt/sync/timer.h
new file mode 100644
index 00000000..509fd22c
--- /dev/null
+++ b/src/rt/sync/timer.h
@@ -0,0 +1,25 @@
+/*
+ *  Utility class to measure time in a platform independent way.
+ */
+
+#ifndef TIMER_H
+#define TIMER_H
+
+class timer {
+private:
+    uint64_t _start;
+    uint64_t _timeout;
+    uint64_t get_time();
+#if __WIN32__
+    uint64_t _ticks_per_us;
+#endif
+public:
+    timer();
+    void reset(uint64_t timeout);
+    uint64_t get_elapsed_time();
+    int64_t get_timeout();
+    bool has_timed_out();
+    virtual ~timer();
+};
+
+#endif /* TIMER_H */