V4 Debugger: Avoid looking up values in debugger thread

To avoid interaction with the engine from the debugger thread we
move the value lookup functionality into the data collector, and
drop the RefHolder. Also, we define some more debugger jobs to
move the work the request handlers do into the GUI thread.

Task-number: QTBUG-50481
Change-Id: Id93548dc65133246deac71f73188c715e9dc01e4
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

1 files changed, 72 insertions, 105 deletions

diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp b/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp
index 020be688f3..d60db6cf82 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp
@@ -118,8 +118,79 @@ bool JavaScriptJob::hasExeption() const
     return resultIsException;
 }
 
+BacktraceJob::BacktraceJob(QV4DataCollector *collector, int fromFrame, int toFrame) :
+    CollectJob(collector), fromFrame(fromFrame), toFrame(toFrame)
+{
+}
+
+void BacktraceJob::run()
+{
+    QJsonArray frameArray;
+    QVector<QV4::StackFrame> frames = collector->engine()->stackTrace(toFrame);
+    for (int i = fromFrame; i < toFrame && i < frames.size(); ++i)
+        frameArray.push_back(collector->buildFrame(frames[i], i));
+    if (frameArray.isEmpty()) {
+        result.insert(QStringLiteral("totalFrames"), 0);
+    } else {
+        result.insert(QStringLiteral("fromFrame"), fromFrame);
+        result.insert(QStringLiteral("toFrame"), fromFrame + frameArray.size());
+        result.insert(QStringLiteral("frames"), frameArray);
+    }
+    collectedRefs = collector->flushCollectedRefs();
+}
+
+FrameJob::FrameJob(QV4DataCollector *collector, int frameNr) :
+    CollectJob(collector), frameNr(frameNr), success(false)
+{
+}
+
+void FrameJob::run()
+{
+    QVector<QV4::StackFrame> frames = collector->engine()->stackTrace(frameNr + 1);
+    if (frameNr >= frames.length()) {
+        success = false;
+    } else {
+        result = collector->buildFrame(frames[frameNr], frameNr);
+        collectedRefs = collector->flushCollectedRefs();
+        success = true;
+    }
+}
+
+bool FrameJob::wasSuccessful() const
+{
+    return success;
+}
+
+ScopeJob::ScopeJob(QV4DataCollector *collector, int frameNr, int scopeNr) :
+    CollectJob(collector), frameNr(frameNr), scopeNr(scopeNr), success(false)
+{
+}
+
+void ScopeJob::run()
+{
+    QJsonObject object;
+    success = collector->collectScope(&object, frameNr, scopeNr);
+
+    if (success) {
+        QVector<QV4::Heap::ExecutionContext::ContextType> scopeTypes =
+                QV4DataCollector::getScopeTypes(collector->engine(), frameNr);
+        result[QLatin1String("type")] = QV4DataCollector::encodeScopeType(scopeTypes[scopeNr]);
+    } else {
+        result[QLatin1String("type")] = -1;
+    }
+    result[QLatin1String("index")] = scopeNr;
+    result[QLatin1String("frameIndex")] = frameNr;
+    result[QLatin1String("object")] = object;
+    collectedRefs = collector->flushCollectedRefs();
+}
+
+bool ScopeJob::wasSuccessful() const
+{
+    return success;
+}
+
 ValueLookupJob::ValueLookupJob(const QJsonArray &handles, QV4DataCollector *collector) :
-    collector(collector), handles(handles) {}
+    CollectJob(collector), handles(handles) {}
 
 void ValueLookupJob::run()
 {
@@ -152,16 +223,6 @@ const QString &ValueLookupJob::exceptionMessage() const
     return exception;
 }
 
-const QJsonObject &ValueLookupJob::returnValue() const
-{
-    return result;
-}
-
-const QJsonArray &ValueLookupJob::refs() const
-{
-    return collectedRefs;
-}
-
 ExpressionEvalJob::ExpressionEvalJob(QV4::ExecutionEngine *engine, int frameNr,
                                      const QString &expression, QV4DataCollector *collector) :
     JavaScriptJob(engine, frameNr, expression), collector(collector)
@@ -209,100 +270,6 @@ const QStringList &GatherSourcesJob::result() const
     return sources;
 }
 
-ArgumentCollectJob::ArgumentCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
-                                       QStringList *names, int frameNr, int scopeNr)
-    : engine(engine)
-    , collector(collector)
-    , names(names)
-    , frameNr(frameNr)
-    , scopeNr(scopeNr)
-{}
-
-void ArgumentCollectJob::run()
-{
-    if (frameNr < 0)
-        return;
-
-    QV4::Scope scope(engine);
-    QV4::Scoped<QV4::CallContext> ctxt(
-                scope, QV4DataCollector::findScope(QV4DataCollector::findContext(engine, frameNr), scopeNr));
-    if (!ctxt)
-        return;
-
-    QV4::ScopedValue v(scope);
-    int nFormals = ctxt->formalCount();
-    for (unsigned i = 0, ei = nFormals; i != ei; ++i) {
-        QString qName;
-        if (QV4::Identifier *name = ctxt->formals()[nFormals - i - 1])
-            qName = name->string;
-        names->append(qName);
-        v = ctxt->argument(i);
-        collector->collect(v);
-    }
-}
-
-LocalCollectJob::LocalCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
-                                 QStringList *names, int frameNr, int scopeNr)
-    : engine(engine)
-    , collector(collector)
-    , names(names)
-    , frameNr(frameNr)
-    , scopeNr(scopeNr)
-{}
-
-void LocalCollectJob::run()
-{
-    if (frameNr < 0)
-        return;
-
-    QV4::Scope scope(engine);
-    QV4::Scoped<QV4::CallContext> ctxt(
-                scope, QV4DataCollector::findScope(QV4DataCollector::findContext(engine, frameNr), scopeNr));
-    if (!ctxt)
-        return;
-
-    QV4::ScopedValue v(scope);
-    for (unsigned i = 0, ei = ctxt->variableCount(); i != ei; ++i) {
-        QString qName;
-        if (QV4::Identifier *name = ctxt->variables()[i])
-            qName = name->string;
-        names->append(qName);
-        v = ctxt->d()->locals[i];
-        collector->collect(v);
-    }
-}
-
-ThisCollectJob::ThisCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
-                               int frameNr)
-    : engine(engine)
-    , collector(collector)
-    , frameNr(frameNr)
-    , thisRef(QV4DataCollector::s_invalidRef)
-{}
-
-void ThisCollectJob::run()
-{
-    QV4::Scope scope(engine);
-    QV4::ScopedContext ctxt(scope, QV4DataCollector::findContext(engine, frameNr));
-    while (ctxt) {
-        if (QV4::CallContext *cCtxt = ctxt->asCallContext())
-            if (cCtxt->d()->activation)
-                break;
-        ctxt = ctxt->d()->outer;
-    }
-
-    if (!ctxt)
-        return;
-
-    QV4::ScopedValue o(scope, ctxt->asCallContext()->d()->activation);
-    thisRef = collector->collect(o);
-}
-
-QV4DataCollector::Ref ThisCollectJob::foundRef() const
-{
-    return thisRef;
-}
-
 ExceptionCollectJob::ExceptionCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector)
     : engine(engine)
     , collector(collector)