Debugger: Make updateThreads() a setThreads()

(and keep updateThread() for the single-thread case)

All backends create full lists, making that explicit allows to
simplify the interface.

Change-Id: I717cfcf3ec9f8e81df8a5dfc71ae84855bc3beae
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/debugger/cdb/cdbengine.cpp

@@ -1002,7 +1002,7 @@ void CdbEngine::handleThreads(const DebuggerResponse &response)
                qPrintable(DebuggerResponse::stringFromResultClass(response.resultClass)));
     }
     if (response.resultClass == ResultDone) {
-        threadsHandler()->updateThreads(response.data);
+        threadsHandler()->setThreads(response.data);
         // Continue sequence
         reloadFullStack();
     } else {
@@ -1866,7 +1866,7 @@ void CdbEngine::processStop(const GdbMi &stopReason, bool conditionalBreakPointT
         }
         const GdbMi threads = stopReason["threads"];
         if (threads.isValid()) {
-            threadsHandler()->updateThreads(threads);
+            threadsHandler()->setThreads(threads);
             if (forcedThread)
                 threadsHandler()->setCurrentThread(forcedThread);
         } else {

src/plugins/debugger/gdb/gdbengine.cpp

@@ -2983,12 +2983,7 @@ void GdbEngine::handleThreadInfo(const DebuggerResponse &response)
 {
     if (response.resultClass == ResultDone) {
         ThreadsHandler *handler = threadsHandler();
-        handler->updateThreads(response.data);
+        handler->setThreads(response.data);
-        // This is necessary as the current thread might not be in the list.
-        if (!handler->currentThread()) {
-            if (Thread other = handler->threadAt(0))
-                selectThread(other);
-        }
         updateState(false); // Adjust Threads combobox.
         if (boolSetting(ShowThreadNames)) {
             runCommand({"threadnames " + action(MaximalStackDepth)->value().toString(),

src/plugins/debugger/lldb/lldbengine.cpp

@@ -656,7 +656,7 @@ void LldbEngine::updateAll()
 {
     DebuggerCommand cmd("fetchThreads");
     cmd.callback = [this](const DebuggerResponse &response) {
-        threadsHandler()->updateThreads(response.data);
+        threadsHandler()->setThreads(response.data);
         fetchStack(action(MaximalStackDepth)->value().toInt());
         reloadRegisters();
     };

src/plugins/debugger/threadshandler.cpp

@@ -282,12 +282,6 @@ Thread ThreadsHandler::currentThread() const
     return m_currentThread;
 }
 
-Thread ThreadsHandler::threadAt(int index) const
-{
-    QTC_ASSERT(index >= 0 && index < rootItem()->childCount(), return Thread());
-    return rootItem()->childAt(index);
-}
-
 void ThreadsHandler::setCurrentThread(const Thread &thread)
 {
     if (thread == m_currentThread)
@@ -368,8 +362,10 @@ void ThreadsHandler::notifyStopped(const QString &id)
         thread->notifyStopped();
 }
 
-void ThreadsHandler::updateThreads(const GdbMi &data)
+void ThreadsHandler::setThreads(const GdbMi &data)
 {
+    rootItem()->removeChildren();
+
     // ^done,threads=[{id="1",target-id="Thread 0xb7fdc710 (LWP 4264)",
     // frame={level="0",addr="0x080530bf",func="testQString",args=[],
     // file="/.../app.cpp",fullname="/../app.cpp",line="1175"},
@@ -396,6 +392,9 @@ void ThreadsHandler::updateThreads(const GdbMi &data)
 
     const QString &currentId = data["current-thread-id"].data();
     m_currentThread = threadForId(currentId);
+
+    if (!m_currentThread && !items.isEmpty())
+        m_currentThread = rootItem()->childAt(0);
 }
 
 QAbstractItemModel *ThreadsHandler::model()

src/plugins/debugger/threadshandler.h

@@ -79,13 +79,12 @@ public:
 
     int currentThreadIndex() const;
     Thread currentThread() const;
-    Thread threadAt(int index) const;
     Thread threadForId(const QString &id) const;
     void setCurrentThread(const Thread &thread);
     QString pidForGroupId(const QString &groupId) const;
 
     void updateThread(const ThreadData &threadData);
-    void updateThreads(const GdbMi &data);
+    void setThreads(const GdbMi &data);
 
     void removeThread(const QString &id);
     void removeAll();