dmazzoni's fixes to ALSA for speech_synthesis

tts_service.cc

Index: tts_service.cc
diff --git a/tts_service.cc b/tts_service.cc
index bcb2c31db31d7b453cf2428e2e52746a8d245be7..9f83a2f3088b4eac1a4668052981d5babf0bb26d 100644
--- a/tts_service.cc
+++ b/tts_service.cc
@@ -192,9 +192,11 @@ void TtsService::Run() {
       continue;
     }
 
-    engine_->SetRate(current_utterance_->options->rate);
-    engine_->SetPitch(current_utterance_->options->pitch);
-    engine_->SetVolume(current_utterance_->options->volume);
+    if (current_utterance_->options) {
+      engine_->SetRate(current_utterance_->options->rate);
+      engine_->SetPitch(current_utterance_->options->pitch);
+      engine_->SetVolume(current_utterance_->options->volume);
+    }
 
     // Synthesize the current utterance.  The TTS engine will call our
     // callback method, Receive, repeatedly while it performs synthesis.
@@ -216,14 +218,18 @@ void TtsService::Run() {
       engine_->SetReceiver(this);
     }
 
+    // Save the utterance text because current_utterance_ is deleted
+    // by the Done() callback before the call to SynthesizeText exits.
+    string utterance_text = current_utterance_->text;
+
     engine_->SynthesizeText(
-        current_utterance_->text.c_str(),
+        utterance_text.c_str(),
         audio_buffer_,
         audio_buffer_size_,
         &samples_output);
 
     // TODO(chaitanyag): Make the completion callback here.
-    LOG(INFO) << "Done: " << current_utterance_->text.c_str();
+    LOG(INFO) << "Done: " << utterance_text.c_str();
 
     mutex_->Lock();
     if (utterance_running_ == false) {
@@ -281,6 +287,7 @@ tts_callback_status TtsService::Receive(int rate,
 
   bool success = ring_buffer_->Write(data, num_samples);
   if (!success) {
+    LOG(INFO) << "Unable to write to ring buffer";
     exit(0);
   }