Change lambda into IsBufferFull(). (#58)

This is for compatibility with VS2017, which doesn't support
the unary plus trick for lambdas.

Author: g-easy

opencensus/trace/internal/span_exporter_impl.cc

@@ -57,6 +57,11 @@ void SpanExporterImpl::StartExportThread() {
   thread_started_ = true;
 }
 
+bool SpanExporterImpl::IsBufferFull() const {
+  span_mu_.AssertHeld();
+  return spans_.size() >= buffer_size_;
+}
+
 void SpanExporterImpl::RunWorkerLoop() {
   std::vector<opencensus::trace::exporter::SpanData> span_data_;
   std::vector<std::shared_ptr<opencensus::trace::SpanImpl>> spans_copy_;
@@ -67,14 +72,9 @@ void SpanExporterImpl::RunWorkerLoop() {
     {
       absl::MutexLock l(&span_mu_);
       // Wait until batch is full or interval time has been exceeded.
-      span_mu_.AwaitWithDeadline(absl::Condition(
-                                     +[](SpanExporterImpl* ptr) {
-                                       ptr->span_mu_.AssertHeld();
-                                       return ptr->spans_.size() >=
-                                              ptr->buffer_size_;
-                                     },
-                                     this),
-                                 next_forced_export_time);
+      span_mu_.AwaitWithDeadline(
+          absl::Condition(this, &SpanExporterImpl::IsBufferFull),
+          next_forced_export_time);
       next_forced_export_time = absl::Now() + interval_;
       if (spans_.empty()) {
         continue;

opencensus/trace/internal/span_exporter_impl.h

@@ -66,10 +66,15 @@ class SpanExporterImpl {
 
   void StartExportThread() EXCLUSIVE_LOCKS_REQUIRED(handler_mu_);
   void RunWorkerLoop();
+
   // Calls all registered handlers and exports the spans contained in span_data.
   void Export(const std::vector<SpanData>& span_data);
+
   void ExportForTesting();
 
+  // Returns true if the spans_ buffer has filled up.
+  bool IsBufferFull() const;
+
   static SpanExporterImpl* span_exporter_;
   const uint32_t buffer_size_;
   const absl::Duration interval_;