make the stats code a little more difficult to corrupt

libtransmission/stats.c

@@ -24,7 +24,7 @@
 struct tr_stats_handle
 {
     tr_session_stats single;
-    tr_session_stats cumulative;
+    tr_session_stats old;
     time_t startTime;
 };
 
@@ -115,36 +115,64 @@ void
 tr_statsInit( tr_handle * handle )
 {
     struct tr_stats_handle * stats = tr_new0( struct tr_stats_handle, 1 );
-    loadCumulativeStats( &stats->cumulative );
-    stats->cumulative.sessionCount++;
-    stats->startTime = time(NULL);
+    loadCumulativeStats( &stats->old );
+    stats->single.sessionCount = 1;
+    stats->startTime = time( NULL );
     handle->sessionStats = stats;
 }
 
 void
 tr_statsClose( tr_handle * handle )
 {
-    tr_session_stats tmp;
-    tr_getCumulativeSessionStats( handle, &tmp );
-    saveCumulativeStats( &tmp );
+    tr_session_stats cumulative;
+    tr_getCumulativeSessionStats( handle, &cumulative );
+    saveCumulativeStats( &cumulative );
 
     tr_free( handle->sessionStats );
     handle->sessionStats = NULL;
 }
 
+static struct tr_stats_handle *
+getStats( const tr_handle * handle )
+{
+    static struct tr_stats_handle nullObject;
+
+    return handle && handle->sessionStats
+        ? handle->sessionStats
+        : &nullObject;
+}
+
+/***
+****
+***/
+
 static void
 updateRatio( tr_session_stats * setme )
 {
-    setme->ratio = tr_getRatio( setme->uploadedBytes, setme->downloadedBytes );
+    setme->ratio = tr_getRatio( setme->uploadedBytes,
+                                setme->downloadedBytes );
+}
+
+static void
+addStats( tr_session_stats       * setme,
+          const tr_session_stats * a,
+          const tr_session_stats * b )
+{
+    setme->uploadedBytes   = a->uploadedBytes   + b->uploadedBytes;
+    setme->downloadedBytes = a->downloadedBytes + b->downloadedBytes;
+    setme->filesAdded      = a->filesAdded      + b->filesAdded;
+    setme->sessionCount    = a->sessionCount    + b->sessionCount;
+    setme->secondsActive   = a->secondsActive   + b->secondsActive;
+    updateRatio( setme );
 }
 
 void
 tr_getSessionStats( const tr_handle   * handle,
                     tr_session_stats  * setme )
 {
-    const struct tr_stats_handle * stats = handle->sessionStats;
+    const struct tr_stats_handle * stats = getStats( handle );
     *setme = stats->single;
-    setme->secondsActive += ( time(NULL) - stats->startTime );
+    setme->secondsActive = time( NULL ) - stats->startTime;
     updateRatio( setme );
 }
 
@@ -152,10 +180,9 @@ void
 tr_getCumulativeSessionStats( const tr_handle   * handle,
                               tr_session_stats  * setme )
 {
-    const struct tr_stats_handle * stats = handle->sessionStats;
-    *setme = stats->cumulative;
-    setme->secondsActive += ( time(NULL) - stats->startTime );
-    updateRatio( setme );
+    tr_session_stats current;
+    tr_getSessionStats( handle, &current );
+    addStats( setme, &getStats(handle)->old, &current );
 }
 
 /**
@@ -165,23 +192,17 @@ tr_getCumulativeSessionStats( const tr_handle   * handle,
 void
 tr_statsAddUploaded( tr_handle * handle, uint32_t bytes )
 {
-    struct tr_stats_handle * stats = handle->sessionStats;
-    stats->single.uploadedBytes += bytes;
-    stats->cumulative.uploadedBytes += bytes;
+    getStats(handle)->single.uploadedBytes += bytes;
 }
 
 void
 tr_statsAddDownloaded( tr_handle * handle, uint32_t bytes )
 {
-    struct tr_stats_handle * stats = handle->sessionStats;
-    stats->single.downloadedBytes += bytes;
-    stats->cumulative.downloadedBytes += bytes;
+    getStats(handle)->single.downloadedBytes += bytes;
 }
 
 void
 tr_statsFileCreated( tr_handle * handle )
 {
-    struct tr_stats_handle * stats = handle->sessionStats;
-    ++stats->cumulative.filesAdded;
-    ++stats->single.filesAdded;
+    getStats(handle)->single.filesAdded++;
 }

libtransmission/transmission.c

@@ -393,6 +393,8 @@ tr_close( tr_handle * h )
     const int maxwait_msec = SHUTDOWN_MAX_SECONDS * 1000;
     const uint64_t deadline = tr_date( ) + maxwait_msec;
 
+    tr_statsClose( h );
+
     tr_runInEventThread( h, tr_closeImpl, h );
     while( !h->isClosed && !deadlineReached( deadline ) )
         tr_wait( 100 );
@@ -402,7 +404,6 @@ tr_close( tr_handle * h )
         tr_wait( 100 );
 
     tr_fdClose( );
-    tr_statsClose( h );
     tr_lockFree( h->lock );
     free( h->tag );
     free( h );