Bug 838625 - Add hal::ProcessPriorityToString and use it in ProcessPriorityManager logging. r=cjones, a=bajaj

dom/ipc/ProcessPriorityManager.cpp

@@ -394,8 +394,8 @@ ProcessPriorityManager::SetIsForeground()
     runnable->Cancel();
   }
 
-  LOG("Setting priority to FOREGROUND.");
   mProcessPriority = PROCESS_PRIORITY_FOREGROUND;
+  LOG("Setting priority to %s.", ProcessPriorityToString(mProcessPriority));
   hal::SetProcessPriority(getpid(), PROCESS_PRIORITY_FOREGROUND);
 }
 
@@ -408,7 +408,7 @@ ProcessPriorityManager::SetIsBackgroundNow()
   }
 
   mProcessPriority = backgroundPriority;
-  LOG("Setting priority to BACKGROUND (type %d)", mProcessPriority);
+  LOG("Setting priority to %s", ProcessPriorityToString(mProcessPriority));
   hal::SetProcessPriority(getpid(), mProcessPriority);
 
   // We're in the background; dump as much memory as we can.

hal/Hal.cpp

@@ -838,6 +838,27 @@ SetProcessPriority(int aPid, ProcessPriority aPriority)
   PROXY_IF_SANDBOXED(SetProcessPriority(aPid, aPriority));
 }
 
+// From HalTypes.h.
+const char*
+ProcessPriorityToString(ProcessPriority aPriority)
+{
+  switch (aPriority) {
+  case PROCESS_PRIORITY_MASTER:
+    return "MASTER";
+  case PROCESS_PRIORITY_FOREGROUND:
+    return "FOREGROUND";
+  case PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE:
+    return "BACKGROUND_PERCEIVABLE";
+  case PROCESS_PRIORITY_BACKGROUND_HOMESCREEN:
+    return "BACKGROUND_HOMESCREEN";
+  case PROCESS_PRIORITY_BACKGROUND:
+    return "BACKGROUND";
+  default:
+    MOZ_ASSERT(false);
+    return "???";
+  }
+}
+
 static StaticAutoPtr<ObserverList<FMRadioOperationInformation> > sFMRadioObservers;
 
 static void

hal/HalTypes.h

@@ -79,6 +79,14 @@ enum ProcessPriority {
   NUM_PROCESS_PRIORITY
 };
 
+// Convert a ProcessPriority enum value to a string.  The strings returned by
+// this function are statically allocated; do not attempt to free one!
+//
+// If you pass an unknown process priority (or NUM_PROCESS_PRIORITY), we
+// fatally assert in debug builds and otherwise return "???".
+const char*
+ProcessPriorityToString(ProcessPriority aPriority);
+
 /**
  * Used by ModifyWakeLock
  */