Make canceling of Type Hierarchy evaluation more responsive

On the beginning of the process of evaluating type hierarchy
the evaluating thread may freeze on a first call to
Snapshot::updateDependencyTable() for quite a long time
(e.g. when showing the type hierarchy for IPlugin class
inside Creator project - it may freeze up to about 3 seconds).
So, when we want to cancel the evaluation (e.g. when
we switch from "Type Hierarchy" into another view or when
closing Creator) we may freeze for this period. In order to
fix it we pass a future interface as an additional argument
for Snapshot::updateDependencyTable() and cancel the update
when cancellation of task was requested.

Change-Id: I2147f10a68989587476c30369ec2ac552a57d5ae
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/libs/cplusplus/CppDocument.cpp

@@ -44,11 +44,12 @@
 #include <cplusplus/TypeVisitor.h>
 #include <cplusplus/CoreTypes.h>
 
-#include <QStack>
-#include <QByteArray>
 #include <QBitArray>
-#include <QDir>
+#include <QByteArray>
 #include <QDebug>
+#include <QDir>
+#include <QFutureInterface>
+#include <QStack>
 
 /*!
     \namespace CPlusPlus
@@ -873,9 +874,15 @@ Utils::FilePaths Snapshot::filesDependingOn(const Utils::FilePath &fileName) con
 }
 
 void Snapshot::updateDependencyTable() const
+{
+    QFutureInterfaceBase futureInterface;
+    updateDependencyTable(futureInterface);
+}
+
+void Snapshot::updateDependencyTable(QFutureInterfaceBase &futureInterface) const
 {
     if (m_deps.files.isEmpty())
-        m_deps.build(*this);
+        m_deps.build(futureInterface, *this);
 }
 
 bool Snapshot::operator==(const Snapshot &other) const

src/libs/cplusplus/CppDocument.h

@@ -39,6 +39,10 @@
 #include <QFileInfo>
 #include <QAtomicInt>
 
+QT_BEGIN_NAMESPACE
+class QFutureInterfaceBase;
+QT_END_NAMESPACE
+
 namespace CPlusPlus {
 
 class Macro;
@@ -443,6 +447,7 @@ public:
     Utils::FilePaths filesDependingOn(const QString &fileName) const
     { return filesDependingOn(Utils::FilePath::fromString(fileName)); }
     void updateDependencyTable() const;
+    void updateDependencyTable(QFutureInterfaceBase &futureInterface) const;
 
     bool operator==(const Snapshot &other) const;
 

src/libs/cplusplus/DependencyTable.cpp

@@ -26,6 +26,7 @@
 #include "CppDocument.h"
 
 #include <QDebug>
+#include <QFutureInterface>
 
 using namespace CPlusPlus;
 
@@ -47,13 +48,16 @@ Utils::FilePaths DependencyTable::filesDependingOn(const Utils::FilePath &fileNa
     return deps;
 }
 
-void DependencyTable::build(const Snapshot &snapshot)
+void DependencyTable::build(QFutureInterfaceBase &futureInterface, const Snapshot &snapshot)
 {
     files.clear();
     fileIndex.clear();
     includes.clear();
     includeMap.clear();
 
+    if (futureInterface.isCanceled())
+        return;
+
     const int documentCount = snapshot.size();
     files.resize(documentCount);
     includeMap.resize(documentCount);
@@ -65,6 +69,9 @@ void DependencyTable::build(const Snapshot &snapshot)
         fileIndex[it.key()] = i;
     }
 
+    if (futureInterface.isCanceled())
+        return;
+
     for (int i = 0; i < files.size(); ++i) {
         const Utils::FilePath &fileName = files.at(i);
         if (Document::Ptr doc = snapshot.document(fileName)) {
@@ -81,10 +88,14 @@ void DependencyTable::build(const Snapshot &snapshot)
                     directIncludes.append(index);
 
                 bitmap.setBit(index, true);
+                if (futureInterface.isCanceled())
+                    return;
             }
 
             includeMap[i] = bitmap;
             includes[i] = directIncludes;
+            if (futureInterface.isCanceled())
+                return;
         }
     }
 
@@ -99,12 +110,18 @@ void DependencyTable::build(const Snapshot &snapshot)
 
             foreach (int includedFileIndex, includes.value(i)) {
                 bitmap |= includeMap.value(includedFileIndex);
+                if (futureInterface.isCanceled())
+                    return;
             }
 
             if (bitmap != previousBitmap) {
                 includeMap[i] = bitmap;
                 changed = true;
             }
+            if (futureInterface.isCanceled())
+                return;
         }
+        if (futureInterface.isCanceled())
+            return;
     } while (changed);
 }

src/libs/cplusplus/DependencyTable.h

@@ -35,6 +35,10 @@
 #include <QStringList>
 #include <QVector>
 
+QT_BEGIN_NAMESPACE
+class QFutureInterfaceBase;
+QT_END_NAMESPACE
+
 namespace CPlusPlus {
 
 class Snapshot;
@@ -43,7 +47,7 @@ class CPLUSPLUS_EXPORT DependencyTable
 {
 private:
     friend class Snapshot;
-    void build(const Snapshot &snapshot);
+    void build(QFutureInterfaceBase &futureInterface, const Snapshot &snapshot);
     Utils::FilePaths filesDependingOn(const Utils::FilePath &fileName) const;
 
     QVector<Utils::FilePath> files;

src/plugins/cpptools/cppelementevaluator.cpp

@@ -213,6 +213,7 @@ void CppClass::lookupDerived(QFutureInterfaceBase &futureInterface,
 {
     using Data = QPair<CppClass*, CppTools::TypeHierarchy>;
 
+    snapshot.updateDependencyTable(futureInterface);
     CppTools::TypeHierarchyBuilder builder(declaration, snapshot);
     const CppTools::TypeHierarchy &completeHierarchy = builder.buildDerivedTypeHierarchy(futureInterface);