DAP: Add watcher feature

It is possible currently to add/remove watcher. Also it saves
expanded structure during the debugging process.

Note:
It doesn't work for CMake because of the issue #25282.

Change-Id: Ia0a48ca5cd0062617ae427b56b001ef87d5894ed
Reviewed-by: hjk <hjk@qt.io>

src/plugins/debugger/dap/cmakedapengine.cpp

@@ -147,6 +147,7 @@ bool CMakeDapEngine::hasCapability(unsigned cap) const
     return cap & (ReloadModuleCapability
                   | BreakConditionCapability
                   | ShowModuleSymbolsCapability
+                  /*| AddWatcherCapability*/ // disable while the #25282 bug is not fixed
                   /*| RunToLineCapability*/); // disable while the #25176 bug is not fixed
 }
 

src/plugins/debugger/dap/dapclient.cpp

@@ -114,6 +114,14 @@ void DapClient::sendStepOver(int threadId)
     postRequest("next", QJsonObject{{"threadId", threadId}});
 }
 
+void DapClient::evaluateVariable(const QString &expression, int frameId)
+{
+    postRequest("evaluate",
+                QJsonObject{{"expression", expression},
+                            {"frameId", frameId},
+                            {"context", "variables"}});
+}
+
 void DapClient::stackTrace(int threadId)
 {
     QTC_ASSERT(threadId != -1, return);
@@ -214,6 +222,8 @@ void DapClient::emitSignals(const QJsonDocument &doc)
             type = DapResponseType::DapThreads;
         } else if (command == "pause") {
             type = DapResponseType::Pause;
+        } else if (command == "evaluate") {
+            type = DapResponseType::Evaluate;
         }
         emit responseReady(type, ob);
         return;

src/plugins/debugger/dap/dapclient.h

@@ -51,6 +51,7 @@ enum class DapResponseType
     StepOut,
     StepOver,
     Pause,
+    Evaluate,
     Unknown
 };
 
@@ -93,11 +94,14 @@ public:
     void sendStepOut(int threadId);
     void sendStepOver(int threadId);
 
+    void evaluateVariable(const QString &expression, int frameId);
+
     void stackTrace(int threadId);
     void scopes(int frameId);
     void threads();
     void variables(int variablesReference);
     void setBreakpoints(const QJsonArray &breakpoints, const Utils::FilePath &fileName);
+
     void emitSignals(const QJsonDocument &doc);
 
 signals:

src/plugins/debugger/dap/dapengine.cpp

@@ -63,6 +63,79 @@ using namespace Utils;
 
 namespace Debugger::Internal {
 
+VariablesHandler::VariablesHandler(DapEngine *dapEngine)
+    : m_dapEngine(dapEngine)
+{}
+
+void VariablesHandler::addVariable(const QString &iname, int variablesReference)
+{
+    VariableItem varItem = {iname, variablesReference};
+    bool wasEmpty = m_queue.empty();
+    bool inserted = false;
+
+    for (auto i = m_queue.begin(); i != m_queue.end(); ++i) {
+        if (i->iname > iname) {
+            m_queue.insert(i, varItem);
+            inserted = true;
+            break;
+        }
+    }
+    if (!inserted)
+        m_queue.push_back(varItem);
+
+    if (wasEmpty) {
+        startHandling();
+    }
+}
+
+void VariablesHandler::handleNext()
+{
+    if (m_queue.empty())
+        return;
+
+    m_queue.pop_front();
+    startHandling();
+}
+
+void VariablesHandler::startHandling()
+{
+    if (m_queue.empty())
+        return;
+
+    m_currentVarItem = m_queue.front();
+
+    WatchItem *watchItem = m_dapEngine->watchHandler()->findItem(m_currentVarItem.iname);
+    int variablesReference = m_currentVarItem.variablesReference;
+
+    if (variablesReference == -1 && watchItem && watchItem->iname.startsWith("watch.")
+        && watchItem->iname.split('.').size() == 2) {
+        watchItem->removeChildren();
+        m_dapEngine->dapClient()->evaluateVariable(watchItem->name,
+                                                   m_dapEngine->currentStackFrameId());
+        return;
+    }
+
+    if (variablesReference == -1) {
+        if (watchItem) {
+            variablesReference = watchItem->variablesReference;
+        } else {
+            handleNext();
+            return;
+        }
+    }
+
+    if (variablesReference == 0) {
+        handleNext();
+        return;
+    }
+
+    m_dapEngine->dapClient()->variables(variablesReference);
+}
+
+DapEngine::DapEngine()
+    : m_variablesHandler(std::make_unique<VariablesHandler>(this))
+{}
+
 void DapEngine::executeDebuggerCommand(const QString &/*command*/)
 {
     QTC_ASSERT(state() == InferiorStopOk, qCDebug(logCategory()) << state());
@@ -350,13 +423,6 @@ void DapEngine::refreshModules(const GdbMi &modules)
     handler->endUpdateAll();
 }
 
-void DapEngine::requestModuleSymbols(const Utils::FilePath &/*moduleName*/)
-{
-//    DebuggerCommand cmd("listSymbols");
-//    cmd.arg("module", moduleName);
-//    runCommand(cmd);
-}
-
 void DapEngine::refreshState(const GdbMi &reportedState)
 {
     QString newState = reportedState.data();
@@ -399,50 +465,32 @@ bool DapEngine::canHandleToolTip(const DebuggerToolTipContext &) const
     return state() == InferiorStopOk;
 }
 
-void DapEngine::assignValueInDebugger(WatchItem *, const QString &/*expression*/, const QVariant &/*value*/)
-{
-    //DebuggerCommand cmd("assignValue");
-    //cmd.arg("expression", expression);
-    //cmd.arg("value", value.toString());
-    //runCommand(cmd);
-    //    postDirectCommand("global " + expression + ';' + expression + "=" + value.toString());
-    updateLocals();
-}
-
 void DapEngine::updateItem(const QString &iname)
 {
     WatchItem *item = watchHandler()->findItem(iname);
-    if (item && m_currentWatchItem != item) {
-        m_currentWatchItem = item;
-        m_dapClient->variables(item->variablesReference);
-    }
-}
 
-void DapEngine::getVariableFromQueue()
+    if (item && m_variablesHandler->currentItem().iname != item->iname)
-{
+        m_variablesHandler->addVariable(item->iname, item->variablesReference);
-    WatchItem *item = nullptr;
-    while (!item && !m_variablesReferenceInameQueue.empty()) {
-        item = watchHandler()->findItem(m_variablesReferenceInameQueue.front());
-        m_variablesReferenceInameQueue.pop();
-    }
-
-    if (item) {
-        m_currentWatchItem = item;
-        m_dapClient->variables(item->variablesReference);
-    }
 }
 
 void DapEngine::reexpandItems(const QSet<QString> &inames)
 {
-    QList<QString> inamesVector = inames.values().toVector();
+    QSet<QString> expandedInames = inames;
+    for (auto inames : watchHandler()->watcherNames().keys())
+        expandedInames.insert(watchHandler()->watcherName(inames));
+
+    QList<QString> inamesVector = expandedInames.values().toVector();
     inamesVector.sort();
 
     for (const QString &iname : inamesVector) {
-        if (iname.startsWith("local."))
+        if (iname.startsWith("local.") || iname.startsWith("watch."))
-            m_variablesReferenceInameQueue.push(iname);
+            m_variablesHandler->addVariable(iname, -1);
+    }
 }
 
-    getVariableFromQueue();
+void DapEngine::doUpdateLocals(const UpdateParameters &params)
+{
+    m_variablesHandler->addVariable(params.partialVariable, -1);
 }
 
 QString DapEngine::errorMessage(QProcess::ProcessError error) const
@@ -508,12 +556,6 @@ void DapEngine::handleResponse(DapResponseType type, const QJsonObject &response
 {
     const QString command = response.value("command").toString();
 
-    if (response.contains("success") && !response.value("success").toBool()) {
-        showMessage(QString("DAP COMMAND FAILED: %1").arg(command));
-        qCDebug(logCategory()) << "DAP COMMAND FAILED:" << command;
-        return;
-    }
-
     switch (type) {
     case DapResponseType::Initialize:
         qCDebug(logCategory()) << "initialize success";
@@ -553,9 +595,18 @@ void DapEngine::handleResponse(DapResponseType type, const QJsonObject &response
     case DapResponseType::DapThreads:
         handleThreadsResponse(response);
         break;
+    case DapResponseType::Evaluate:
+        handleEvaluateResponse(response);
+        break;
     default:
         showMessage("UNKNOWN RESPONSE:" + command);
     };
+
+    if (response.contains("success") && !response.value("success").toBool()) {
+        showMessage(QString("DAP COMMAND FAILED: %1").arg(command));
+        qCDebug(logCategory()) << "DAP COMMAND FAILED:" << command;
+        return;
+    }
 }
 
 void DapEngine::handleStackTraceResponse(const QJsonObject &response)
@@ -581,24 +632,17 @@ void DapEngine::handleScopesResponse(const QJsonObject &response)
     if (!response.value("success").toBool())
         return;
 
-    watchHandler()->removeAllData();
     watchHandler()->notifyUpdateStarted();
 
-    m_watchItems.clear();
-
     QJsonArray scopes = response.value("body").toObject().value("scopes").toArray();
     for (const QJsonValueRef &scope : scopes) {
         const QString name = scope.toObject().value("name").toString();
         if (name == "Registers")
             continue;
-        m_variablesReferenceQueue.push(scope.toObject().value("variablesReference").toInt());
+        m_variablesHandler->addVariable("", scope.toObject().value("variablesReference").toInt());
     }
 
-    if (!m_variablesReferenceQueue.empty()) {
+    if (m_variablesHandler->queueSize() == 0) {
-        m_isFirstLayer = true;
-        m_dapClient->variables(m_variablesReferenceQueue.front());
-        m_variablesReferenceQueue.pop();
-    } else {
         watchHandler()->notifyUpdateFinished();
     }
 }
@@ -625,6 +669,28 @@ void DapEngine::handleThreadsResponse(const QJsonObject &response)
     }
 }
 
+void DapEngine::handleEvaluateResponse(const QJsonObject &response)
+{
+    WatchItem *watchItem = watchHandler()->findItem(
+        m_variablesHandler->currentItem().iname);
+    if (watchItem
+        && response.value("body").toObject().contains("variablesReference")) {
+        watchItem->variablesReference
+            = response.value("body").toObject().value("variablesReference").toInt();
+        watchItem->value
+            = response.value("body").toObject().value("result").toString();
+        watchItem->type = response.value("body").toObject().value("type").toString();
+        watchItem->wantsChildren = watchItem->variablesReference > 0;
+
+        watchItem->updateValueCache();
+        watchItem->update();
+
+        m_variablesHandler->addVariable(watchItem->iname,
+                                        watchItem->variablesReference);
+    }
+    m_variablesHandler->handleNext();
+}
+
 void DapEngine::handleEvent(DapEventType type, const QJsonObject &event)
 {
     const QString eventType = event.value("event").toString();
@@ -740,51 +806,42 @@ void DapEngine::handleBreakpointEvent(const QJsonObject &event)
 
 void DapEngine::refreshLocals(const QJsonArray &variables)
 {
+    WatchItem *currentItem = watchHandler()->findItem(m_variablesHandler->currentItem().iname);
+    if (currentItem && currentItem->iname.startsWith("watch"))
+        currentItem->removeChildren();
+
     for (auto variable : variables) {
         WatchItem *item = new WatchItem;
         const QString name = variable.toObject().value("name").toString();
-        if (m_isFirstLayer)
+
-            item->iname = "local." + name;
+        item->iname = (currentItem ? currentItem->iname : "local") + "."
-        else
+                      + name;
-            item->iname = m_currentWatchItem->iname + "." + name;
         item->name = name;
         item->type = variable.toObject().value("type").toString();
         item->value = variable.toObject().value("value").toString();
         item->address = variable.toObject().value("address").toInt();
         item->type = variable.toObject().value("type").toString();
+        item->variablesReference = variable.toObject().value("variablesReference").toInt();
+        item->wantsChildren = item->variablesReference > 0;
 
-        const int variablesReference = variable.toObject().value("variablesReference").toInt();
+        qCDebug(logCategory()) << "variable" << item->iname << item->variablesReference;
-        item->variablesReference = variablesReference;
+        if (currentItem)
-        if (variablesReference > 0)
+            currentItem->appendChild(item);
-            item->wantsChildren = true;
-
-        qCDebug(logCategory()) << "variable" << item->iname << variablesReference;
-        if (m_isFirstLayer)
-            m_watchItems.append(item);
         else
-            m_currentWatchItem->appendChild(item);
-    }
-
-    if (m_isFirstLayer) {
-        if (m_variablesReferenceQueue.empty()) {
-            for (auto item : m_watchItems)
             watchHandler()->insertItem(item);
-            m_isFirstLayer = false;
+    }
+
+    QModelIndex idx = watchHandler()->model()->indexForItem(currentItem);
+    if (currentItem && idx.isValid() && idx.data(LocalsExpandedRole).toBool()) {
+        emit watchHandler()->model()->inameIsExpanded(currentItem->iname);
+        emit watchHandler()->model()->itemIsExpanded(idx);
+    }
+
+    if (m_variablesHandler->queueSize() == 1 && currentItem == nullptr) {
         watchHandler()->notifyUpdateFinished();
-        } else {
-            m_dapClient->variables(m_variablesReferenceQueue.front());
-            m_variablesReferenceQueue.pop();
-        }
-        return;
     }
 
-    if (m_currentWatchItem) {
+    m_variablesHandler->handleNext();
-        emit watchHandler()->model()->inameIsExpanded(m_currentWatchItem->iname);
-        emit watchHandler()->model()->itemIsExpanded(
-            watchHandler()->model()->indexForItem(m_currentWatchItem));
-    }
-
-    getVariableFromQueue();
 }
 
 void DapEngine::refreshStack(const QJsonArray &stackFrames)

src/plugins/debugger/dap/dapengine.h

@@ -20,6 +20,30 @@ class IDataProvider;
 class GdbMi;
 enum class DapResponseType;
 enum class DapEventType;
+class DapEngine;
+
+class VariablesHandler {
+public:
+    VariablesHandler(DapEngine *dapEngine);
+
+    struct VariableItem {
+        QString iname;
+        int variablesReference;
+    };
+
+    void addVariable(const QString &iname, int variablesReference);
+    void handleNext();
+
+    VariableItem currentItem() const { return m_currentVarItem; }
+    int queueSize() const { return m_queue.size(); }
+
+private:
+    void startHandling();
+
+    DapEngine *m_dapEngine;
+    std::list<VariableItem> m_queue;
+    VariableItem m_currentVarItem;
+};
 
 /*
  * A debugger engine for the debugger adapter protocol.
@@ -27,9 +51,12 @@ enum class DapEventType;
 class DapEngine : public DebuggerEngine
 {
 public:
-    DapEngine() = default;
+    DapEngine();
     ~DapEngine() override = default;
 
+    DapClient *dapClient() const { return m_dapClient; }
+    int currentStackFrameId() const { return m_currentStackFrameId; }
+
 protected:
     void executeStepIn(bool) override;
     void executeStepOut() override;
@@ -55,13 +82,10 @@ protected:
     void updateBreakpoint(const Breakpoint &bp) override;
     void removeBreakpoint(const Breakpoint &bp) override;
 
-    void assignValueInDebugger(WatchItem *item,
-        const QString &expr, const QVariant &value) override;
     void executeDebuggerCommand(const QString &command) override;
 
     void loadSymbols(const Utils::FilePath &moduleName) override;
     void loadAllSymbols() override;
-    void requestModuleSymbols(const Utils::FilePath &moduleName) override;
     void reloadModules() override;
     void reloadRegisters() override {}
     void reloadSourceFiles() override {}
@@ -70,6 +94,7 @@ protected:
     bool supportsThreads() const { return true; }
     void updateItem(const QString &iname) override;
     void reexpandItems(const QSet<QString> &inames) override;
+    void doUpdateLocals(const UpdateParameters &params) override;
     void getVariableFromQueue();
 
     void runCommand(const DebuggerCommand &cmd) override;
@@ -102,6 +127,7 @@ protected:
     void handleStackTraceResponse(const QJsonObject &response);
     void handleScopesResponse(const QJsonObject &response);
     void handleThreadsResponse(const QJsonObject &response);
+    void handleEvaluateResponse(const QJsonObject &response);
 
     void handleEvent(DapEventType type, const QJsonObject &event);
     void handleBreakpointEvent(const QJsonObject &event);
@@ -118,11 +144,7 @@ protected:
     int m_currentThreadId = -1;
     int m_currentStackFrameId = -1;
 
-    bool m_isFirstLayer = true;
+    std::unique_ptr<VariablesHandler> m_variablesHandler;
-    std::queue<int> m_variablesReferenceQueue;
-    std::queue<QString> m_variablesReferenceInameQueue;
-    WatchItem *m_currentWatchItem = nullptr;
-    QList<WatchItem *> m_watchItems;
 
     virtual const QLoggingCategory &logCategory()
     {