Clang: Only get one diagnostic for a time out

Otherwise we can stall the backend process.

Change-Id: I854d117546ad08026be8a42854739cabad8b67fd
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/tools/clangbackend/ipcsource/clangipcserver.cpp

@@ -30,6 +30,7 @@
 
 #include "clangipcserver.h"
 
+#include "clangfilesystemwatcher.h"
 #include "codecompleter.h"
 #include "diagnosticset.h"
 #include "projectpartsdonotexistexception.h"
@@ -64,8 +65,7 @@ ClangIpcServer::ClangIpcServer()
                                                           client()->diagnosticsChanged(message);
                                                       });
 
-    sendDiagnosticsTimer.setInterval(2000);
-    sendDiagnosticsTimer.setSingleShot(true);
+    sendDiagnosticsTimer.setInterval(1000);
     QObject::connect(&sendDiagnosticsTimer,
                      &QTimer::timeout,
                      [this] () { translationUnits.sendChangedDiagnostics(); });

src/tools/clangbackend/ipcsource/translationunits.cpp

@@ -136,8 +136,10 @@ void TranslationUnits::updateTranslationUnitsWithChangedDependencies(const Utf8S
 void TranslationUnits::sendChangedDiagnostics()
 {
     for (const auto &translationUnit : translationUnits_) {
-        if (translationUnit.hasNewDiagnostics())
+        if (translationUnit.hasNewDiagnostics()) {
              sendDiagnosticChangedMessage(translationUnit);
+             break;
+        }
     }
 }