From 375a2fdeb4dc162d8bdf7cd1d76d2e34e4c6fde4 Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Tue, 12 Jun 2001 18:58:04 +0000
Subject: [PATCH] fix threading crash in pstats

---
 pandatool/src/gtk-stats/gtkStatsMonitor.cxx |  4 +-
 pandatool/src/pstatserver/pStatReader.cxx   | 62 +++++++++++++++------
 pandatool/src/pstatserver/pStatReader.h     | 16 ++++++
 3 files changed, 61 insertions(+), 21 deletions(-)

diff --git a/pandatool/src/gtk-stats/gtkStatsMonitor.cxx b/pandatool/src/gtk-stats/gtkStatsMonitor.cxx
index e1bed14be3..3b5308d373 100644
--- a/pandatool/src/gtk-stats/gtkStatsMonitor.cxx
+++ b/pandatool/src/gtk-stats/gtkStatsMonitor.cxx
@@ -219,9 +219,7 @@ has_idle() {
 ////////////////////////////////////////////////////////////////////
 bool GtkStatsMonitor::
 is_thread_safe() {
-  // Temporarily set to false to check a possible threading bug.  In
-  // principle, this should work at true.
-  return false;
+  return true;
 }
 
 ////////////////////////////////////////////////////////////////////
diff --git a/pandatool/src/pstatserver/pStatReader.cxx b/pandatool/src/pstatserver/pStatReader.cxx
index fdfb60420f..6efd8a55bc 100644
--- a/pandatool/src/pstatserver/pStatReader.cxx
+++ b/pandatool/src/pstatserver/pStatReader.cxx
@@ -122,6 +122,7 @@ lost_connection() {
 ////////////////////////////////////////////////////////////////////
 void PStatReader::
 idle() {
+  dequeue_frame_data();
   _monitor->idle();
 }
 
@@ -267,24 +268,49 @@ handle_client_udp_data(const Datagram &datagram) {
     nassertv(initial_byte == 0);
   }
 
-  int thread_index = source.get_uint16();
-  int frame_number = source.get_uint32();
-  PStatFrameData *frame_data = new PStatFrameData;
-  frame_data->read_datagram(source, _client_data);
-
-  // Check to see if any new collectors have level data.
-  int num_levels = frame_data->get_num_levels();
-  for (int i = 0; i < num_levels; i++) {
-    int collector_index = frame_data->get_level_collector(i);
-    if (!_client_data->get_collector_has_level(collector_index)) {
-      // This collector is now reporting level data, and it wasn't
-      // before.
-      _client_data->set_collector_has_level(collector_index, true);
-      _monitor->new_collector(collector_index);
-    }
+  if (!_queued_frame_data.full()) {
+    FrameData data;
+    data._thread_index = source.get_uint16();
+    data._frame_number = source.get_uint32();
+    data._frame_data = new PStatFrameData;
+    data._frame_data->read_datagram(source, _client_data);
+    
+    // Queue up the data till we're ready to handle it in a
+    // single-threaded way.
+    _queued_frame_data.push_back(data);
+  }
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: PStatReader::dequeue_frame_data
+//       Access: Private
+//  Description: Called during the idle loop to pull out all the frame
+//               data that we might have read while the threaded
+//               reader was running.
+////////////////////////////////////////////////////////////////////
+void PStatReader::
+dequeue_frame_data() {
+  while (!_queued_frame_data.empty()) {
+    const FrameData &data = _queued_frame_data.front();
+
+    // Check to see if any new collectors have level data.
+    int num_levels = data._frame_data->get_num_levels();
+    for (int i = 0; i < num_levels; i++) {
+      int collector_index = data._frame_data->get_level_collector(i);
+      if (!_client_data->get_collector_has_level(collector_index)) {
+        // This collector is now reporting level data, and it wasn't
+        // before.
+        _client_data->set_collector_has_level(collector_index, true);
+        _monitor->new_collector(collector_index);
+      }
+    }
+
+    _client_data->record_new_frame(data._thread_index, 
+                                   data._frame_number, 
+                                   data._frame_data);
+    _monitor->new_data(data._thread_index, data._frame_number);
+
+    _queued_frame_data.pop_front();
   }
-
-  _client_data->record_new_frame(thread_index, frame_number, frame_data);
-  _monitor->new_data(thread_index, frame_number);
 }
 
diff --git a/pandatool/src/pstatserver/pStatReader.h b/pandatool/src/pstatserver/pStatReader.h
index 48e3a4e86c..3a8da0ae3a 100644
--- a/pandatool/src/pstatserver/pStatReader.h
+++ b/pandatool/src/pstatserver/pStatReader.h
@@ -27,10 +27,16 @@
 #include <connectionReader.h>
 #include <connectionWriter.h>
 #include <referenceCount.h>
+#include <circBuffer.h>
 
 class PStatServer;
 class PStatMonitor;
 class PStatClientControlMessage;
+class PStatFrameData;
+
+// This is the maximum number of frame records that will be queued up
+// from this particular client between processing loops.
+static const int queued_frame_records = 500;
 
 ////////////////////////////////////////////////////////////////////
 //       Class : PStatReader
@@ -58,6 +64,7 @@ private:
 
   void handle_client_control_message(const PStatClientControlMessage &message);
   void handle_client_udp_data(const Datagram &datagram);
+  void dequeue_frame_data();
 
 private:
   PStatServer *_manager;
@@ -71,6 +78,15 @@ private:
   PT(PStatClientData) _client_data;
 
   string _hostname;
+
+  class FrameData {
+  public:
+    int _thread_index;
+    int _frame_number;
+    PStatFrameData *_frame_data;
+  };
+  typedef CircBuffer<FrameData, queued_frame_records> QueuedFrameData;
+  QueuedFrameData _queued_frame_data;
 };
 
 #endif