QbsProjectManager: Build up the project tree in a dedicated thread

... and only switch the root node in the UI thread.
Creating the project tree can take some time for larger projects; no
need to block the UI for that.

Task-number: QTCREATORBUG-18533
Change-Id: I093dc9fb8f3454011a3c64bcc0f785e8b7753b4e
Reviewed-by: hjk <hjk@qt.io>

4 files changed, 81 insertions, 46 deletions

diff --git a/src/plugins/qbsprojectmanager/qbsnodetreebuilder.cpp b/src/plugins/qbsprojectmanager/qbsnodetreebuilder.cpp
index bcf52a96f1f..18a994d3844 100644
--- a/src/plugins/qbsprojectmanager/qbsnodetreebuilder.cpp
+++ b/src/plugins/qbsprojectmanager/qbsnodetreebuilder.cpp
@@ -194,32 +194,32 @@ static QStringList unreferencedBuildSystemFiles(const QJsonObject &project)
     return unreferenced;
 }
 
-std::unique_ptr<QbsProjectNode> QbsNodeTreeBuilder::buildTree(const QbsBuildSystem *buildSystem)
+QbsProjectNode *QbsNodeTreeBuilder::buildTree(const QString &projectName,
+                                              const Utils::FilePath &projectFile,
+                                              const Utils::FilePath &projectDir,
+                                              const QJsonObject &projectData)
 {
-    const Project * const project = buildSystem->project();
-    auto root = std::make_unique<QbsProjectNode>(buildSystem->projectData());
+    auto root = std::make_unique<QbsProjectNode>(projectData);
 
     // If we have no project information at all (i.e. it could not be properly parsed),
     // create the main project file node "manually".
-    if (buildSystem->projectData().isEmpty()) {
-        auto fileNode = std::make_unique<FileNode>(project->projectFilePath(), FileType::Project);
+    if (projectData.isEmpty()) {
+        auto fileNode = std::make_unique<FileNode>(projectFile, FileType::Project);
         root->addNode(std::move(fileNode));
     } else {
         setupProjectNode(root.get());
     }
 
     if (root->displayName().isEmpty())
-        root->setDisplayName(project->displayName());
+        root->setDisplayName(projectName);
     if (root->displayName().isEmpty())
-        root->setDisplayName(project->projectFilePath().toFileInfo().completeBaseName());
+        root->setDisplayName(projectFile.toFileInfo().completeBaseName());
 
-    auto buildSystemFiles = std::make_unique<FolderNode>(project->projectDirectory());
+    auto buildSystemFiles = std::make_unique<FolderNode>(projectDir);
     buildSystemFiles->setDisplayName(QCoreApplication::translate("QbsProjectNode", "Qbs files"));
 
-    const FilePath projectDir = project->projectDirectory();
-    const FilePath buildDir = FilePath::fromString(buildSystem->projectData()
-                                                   .value("build-directory").toString());
-    const QStringList files = unreferencedBuildSystemFiles(buildSystem->projectData());
+    const FilePath buildDir = FilePath::fromString(projectData.value("build-directory").toString());
+    const QStringList files = unreferencedBuildSystemFiles(projectData);
     for (const QString &f : files) {
         const FilePath filePath = FilePath::fromString(f);
         if (filePath.isChildOf(projectDir)) {
@@ -230,7 +230,7 @@ std::unique_ptr<QbsProjectNode> QbsNodeTreeBuilder::buildTree(const QbsBuildSyst
     }
     buildSystemFiles->compress();
     root->addNode(std::move(buildSystemFiles));
-    return root;
+    return root.release();
 }
 
 } // namespace Internal
diff --git a/src/plugins/qbsprojectmanager/qbsnodetreebuilder.h b/src/plugins/qbsprojectmanager/qbsnodetreebuilder.h
index 3c2cd450dc3..7bbff704ac8 100644
--- a/src/plugins/qbsprojectmanager/qbsnodetreebuilder.h
+++ b/src/plugins/qbsprojectmanager/qbsnodetreebuilder.h
@@ -25,18 +25,29 @@
 
 #pragma once
 
+#include <QtGlobal>
+
 #include <memory>
 
+QT_BEGIN_NAMESPACE
+class QJsonObject;
+class QString;
+QT_END_NAMESPACE
+
+namespace Utils { class FilePath; }
+
 namespace QbsProjectManager {
 namespace Internal {
 
-class QbsBuildSystem;
 class QbsProjectNode;
 
 class QbsNodeTreeBuilder
 {
 public:
-    static std::unique_ptr<QbsProjectNode> buildTree(const QbsBuildSystem *buildSystem);
+    static QbsProjectNode *buildTree(const QString &projectName,
+                                     const Utils::FilePath &projectFile,
+                                     const Utils::FilePath &projectDir,
+                                     const QJsonObject &projectData);
 };
 
 } // namespace Internal
diff --git a/src/plugins/qbsprojectmanager/qbsproject.cpp b/src/plugins/qbsprojectmanager/qbsproject.cpp
index dba851338e0..f5b2538dc87 100644
--- a/src/plugins/qbsprojectmanager/qbsproject.cpp
+++ b/src/plugins/qbsprojectmanager/qbsproject.cpp
@@ -67,6 +67,7 @@
 #include <utils/algorithm.h>
 #include <utils/hostosinfo.h>
 #include <utils/qtcassert.h>
+#include <utils/runextensions.h>
 #include <qmljs/qmljsmodelmanagerinterface.h>
 #include <qmljstools/qmljsmodelmanager.h>
 #include <qtsupport/qtcppkitinfo.h>
@@ -214,8 +215,7 @@ QbsBuildSystem::QbsBuildSystem(QbsBuildConfiguration *bc)
     connect(&m_parsingDelay, &QTimer::timeout, this, &QbsBuildSystem::triggerParsing);
 
     connect(bc->project(), &Project::projectFileIsDirty, this, &QbsBuildSystem::delayParsing);
-
-    rebuildProjectTree();
+    updateProjectNodes({});
 }
 
 QbsBuildSystem::~QbsBuildSystem()
@@ -447,6 +447,7 @@ bool QbsBuildSystem::checkCancelStatus()
     qCDebug(qbsPmLog) << "Cancel request while parsing, starting re-parse";
     m_qbsProjectParser->deleteLater();
     m_qbsProjectParser = nullptr;
+    m_treeCreationWatcher = nullptr;
     m_guard = {};
     parseCurrentBuildConfiguration();
     return true;
@@ -456,15 +457,18 @@ void QbsBuildSystem::updateAfterParse()
 {
     qCDebug(qbsPmLog) << "Updating data after parse";
     OpTimer opTimer("updateAfterParse");
-    updateProjectNodes();
-    updateDocuments();
-    updateBuildTargetData();
-    updateCppCodeModel();
-    updateExtraCompilers();
-    updateQmlJsCodeModel();
-    emit project()->fileListChanged();
-    m_envCache.clear();
-    emitBuildSystemUpdated();
+    updateProjectNodes([this] {
+        updateDocuments();
+        updateBuildTargetData();
+        updateCppCodeModel();
+        updateExtraCompilers();
+        updateQmlJsCodeModel();
+        emit project()->fileListChanged();
+        m_envCache.clear();
+        m_guard.markAsSuccess();
+        m_guard = {};
+        emitBuildSystemUpdated();
+    });
 }
 
 void QbsBuildSystem::delayedUpdateAfterParse()
@@ -472,10 +476,32 @@ void QbsBuildSystem::delayedUpdateAfterParse()
     QTimer::singleShot(0, this, &QbsBuildSystem::updateAfterParse);
 }
 
-void QbsBuildSystem::updateProjectNodes()
+void QbsBuildSystem::updateProjectNodes(const std::function<void ()> &continuation)
 {
-    OpTimer opTimer("updateProjectNodes");
-    rebuildProjectTree();
+    m_treeCreationWatcher = new TreeCreationWatcher(this);
+    connect(m_treeCreationWatcher, &TreeCreationWatcher::finished, this,
+            [this, watcher = m_treeCreationWatcher, continuation] {
+        std::unique_ptr<QbsProjectNode> rootNode(m_treeCreationWatcher->result());
+        if (watcher != m_treeCreationWatcher) {
+            watcher->deleteLater();
+            return;
+        }
+        OpTimer("updateProjectNodes continuation");
+        m_treeCreationWatcher->deleteLater();
+        m_treeCreationWatcher = nullptr;
+        if (target() != project()->activeTarget()
+                || target()->activeBuildConfiguration()->buildSystem() != this) {
+            return;
+        }
+        project()->setDisplayName(rootNode->displayName());
+        setRootProjectNode(std::move(rootNode));
+        if (continuation)
+            continuation();
+    });
+    m_treeCreationWatcher->setFuture(runAsync(ProjectExplorerPlugin::sharedThreadPool(),
+            QThread::LowPriority, &QbsNodeTreeBuilder::buildTree,
+            project()->displayName(), project()->projectFilePath(), project()->projectDirectory(),
+            projectData()));
 }
 
 FilePath QbsBuildSystem::installRoot()
@@ -525,8 +551,10 @@ void QbsBuildSystem::handleQbsParsingDone(bool success)
     delete m_qbsUpdateFutureInterface;
     m_qbsUpdateFutureInterface = nullptr;
 
-    if (dataChanged)
+    if (dataChanged) {
         updateAfterParse();
+        return;
+    }
     else if (envChanged)
         updateCppCodeModel();
     if (success)
@@ -539,13 +567,6 @@ void QbsBuildSystem::handleQbsParsingDone(bool success)
     emitBuildSystemUpdated();
 }
 
-void QbsBuildSystem::rebuildProjectTree()
-{
-    std::unique_ptr<QbsProjectNode> newRoot = QbsNodeTreeBuilder::buildTree(this);
-    project()->setDisplayName(newRoot->displayName());
-    setRootProjectNode(std::move(newRoot));
-}
-
 void QbsBuildSystem::changeActiveTarget(Target *t)
 {
     if (t)
@@ -609,6 +630,7 @@ void QbsBuildSystem::parseCurrentBuildConfiguration()
 
     QTC_ASSERT(!m_qbsProjectParser, return);
     m_qbsProjectParser = new QbsProjectParser(this, m_qbsUpdateFutureInterface);
+    m_treeCreationWatcher = nullptr;
     connect(m_qbsProjectParser, &QbsProjectParser::done,
             this, &QbsBuildSystem::handleQbsParsingDone);
 
@@ -636,10 +658,11 @@ void QbsBuildSystem::updateAfterBuild()
     }
     qCDebug(qbsPmLog) << "Updating data after build";
     m_projectData = projectData;
-    updateProjectNodes();
-    updateBuildTargetData();
-    updateExtraCompilers();
-    m_envCache.clear();
+    updateProjectNodes([this] {
+        updateBuildTargetData();
+        updateExtraCompilers();
+        m_envCache.clear();
+    });
 }
 
 void QbsBuildSystem::generateErrors(const ErrorInfo &e)
diff --git a/src/plugins/qbsprojectmanager/qbsproject.h b/src/plugins/qbsprojectmanager/qbsproject.h
index 8f19cc0f036..250d544e3b0 100644
--- a/src/plugins/qbsprojectmanager/qbsproject.h
+++ b/src/plugins/qbsprojectmanager/qbsproject.h
@@ -36,10 +36,13 @@
 
 #include <utils/environment.h>
 
+#include <QFutureWatcher>
 #include <QHash>
 #include <QJsonObject>
 #include <QTimer>
 
+#include <functional>
+
 namespace CppTools { class CppProjectUpdater; }
 
 namespace QbsProjectManager {
@@ -125,11 +128,7 @@ private:
     friend class QbsProject;
 
     void handleQbsParsingDone(bool success);
-
-    void rebuildProjectTree();
-
     void changeActiveTarget(ProjectExplorer::Target *t);
-
     void prepareForParsing();
     void updateDocuments();
     void updateCppCodeModel();
@@ -141,7 +140,7 @@ private:
     bool checkCancelStatus();
     void updateAfterParse();
     void delayedUpdateAfterParse();
-    void updateProjectNodes();
+    void updateProjectNodes(const std::function<void()> &continuation);
     Utils::FilePath installRoot();
 
     static bool ensureWriteableQbsFile(const QString &file);
@@ -153,6 +152,8 @@ private:
     QTimer m_parsingDelay;
     QbsProjectParser *m_qbsProjectParser = nullptr;
     QFutureInterface<bool> *m_qbsUpdateFutureInterface = nullptr;
+    using TreeCreationWatcher = QFutureWatcher<QbsProjectNode *>;
+    TreeCreationWatcher *m_treeCreationWatcher = nullptr;
     Utils::Environment m_lastParseEnv;
     bool m_parsingScheduled = false;