ProjectExplorer: Move BuildSystem owership to BuildConfiguration

... or Target.

This patch moves build system from conceptually "one per project"
to "one per target (i.e. per project-and-kit)" or "per
BuildConfigurations" for targets where the builds differ
significantly.

Building requires usually items from the kit (Qt version, compiler,
...) so a target-agnostic build is practically almost always wrong.

Moving the build system to the target also has the potential
to solve issues caused by switching targets while parsing, that
used Project::activeTarget() regularly, with potentially different
results before and after the switch.

This patch might create performance/size regressions when several
targets are set up per project as the build system implementation's
internal data are duplicated in this case.

The idea is to fix that by sharing per-project pieces again in
the project implementation once these problems occur.

Change-Id: I87f640ce418b93175b5029124eaa55f3b8721dca
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildsystem.h

@@ -25,8 +25,12 @@
 
 #pragma once
 
+#include "builddirmanager.h"
+
 #include <projectexplorer/buildsystem.h>
 
+namespace ProjectExplorer { class ExtraCompiler; }
+
 namespace CppTools {
 class CppProjectUpdater;
 } // namespace CppTools
@@ -37,7 +41,6 @@ class CMakeProject;
 
 namespace Internal {
 class CMakeBuildConfiguration;
-} // namespace Internal
 
 // --------------------------------------------------------------------
 // CMakeBuildSystem:
@@ -48,12 +51,10 @@ class CMakeBuildSystem : public ProjectExplorer::BuildSystem
     Q_OBJECT
 
 public:
-    explicit CMakeBuildSystem(ProjectExplorer::Project *project);
+    explicit CMakeBuildSystem(CMakeBuildConfiguration *bc);
     ~CMakeBuildSystem() final;
 
-protected:
-    bool validateParsingContext(const ParsingContext &ctx) final;
-    void parseProject(ParsingContext &&ctx) final;
+    void triggerParsing() final;
 
     bool supportsAction(ProjectExplorer::Node *context,
                         ProjectExplorer::ProjectAction action,
@@ -62,20 +63,49 @@ protected:
     bool addFiles(ProjectExplorer::Node *context,
                   const QStringList &filePaths, QStringList *) final;
 
-private:
+    QStringList filesGeneratedFrom(const QString &sourceFile) const final;
+
+    void runCMake();
+    void runCMakeAndScanProjectTree();
+
+    // Context menu actions:
+    void buildCMakeTarget(const QString &buildTarget);
     // Treescanner states:
     void handleTreeScanningFinished();
 
+    bool persistCMakeState();
+    void clearCMakeCache();
+
     // Parser states:
-    void handleParsingSuccess(Internal::CMakeBuildConfiguration *bc);
-    void handleParsingError(Internal::CMakeBuildConfiguration *bc);
+    void handleParsingSuccess();
+    void handleParsingError();
+
+    ProjectExplorer::BuildConfiguration *buildConfiguration() const;
+    CMakeBuildConfiguration *cmakeBuildConfiguration() const;
+
+    const QList<ProjectExplorer::BuildTargetInfo> appTargets() const;
+    QStringList buildTargetTitles() const;
+    const QList<CMakeBuildTarget> &buildTargets() const;
+    ProjectExplorer::DeploymentData deploymentData() const;
+
+private:
+    std::unique_ptr<CMakeProjectNode> generateProjectTree(
+            const QList<const ProjectExplorer::FileNode *> &allFiles);
 
     // Combining Treescanner and Parser states:
     void combineScanAndParse();
 
-    void updateProjectData(CMakeProject *p, Internal::CMakeBuildConfiguration *bc);
-    QList<ProjectExplorer::ExtraCompiler *> findExtraCompilers(CMakeProject *p);
-    void updateQmlJSCodeModel(CMakeProject *p, Internal::CMakeBuildConfiguration *bc);
+    void checkAndReportError(QString &errorMessage);
+
+    void updateProjectData();
+    QList<ProjectExplorer::ExtraCompiler *> findExtraCompilers();
+    void updateQmlJSCodeModel();
+
+    void handleParsingSucceeded();
+    void handleParsingFailed(const QString &msg);
+
+    CMakeBuildConfiguration *m_buildConfiguration = nullptr;
+    BuildDirManager m_buildDirManager;
 
     ProjectExplorer::TreeScanner m_treeScanner;
     QHash<QString, bool> m_mimeBinaryCache;
@@ -85,12 +115,12 @@ private:
     bool m_waitingForParse = false;
     bool m_combinedScanAndParseResult = false;
 
-    ParsingContext m_currentContext;
+    ParseGuard m_currentGuard;
 
     CppTools::CppProjectUpdater *m_cppCodeModelUpdater = nullptr;
     QList<ProjectExplorer::ExtraCompiler *> m_extraCompilers;
-
-    friend class Internal::CMakeBuildConfiguration; // For handleParsing* callbacks
+    QList<CMakeBuildTarget> m_buildTargets;
 };
 
+} // namespace Internal
 } // namespace CMakeProjectManager