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#ifndef QBS_BUILDGRAPHEXECUTOR_H
#define QBS_BUILDGRAPHEXECUTOR_H

#include "forward_decls.h"
#include "buildgraphvisitor.h"
#include <buildgraph/artifact.h>
#include <language/forward_decls.h>

#include <logging/logger.h>
#include <tools/buildoptions.h>
#include <tools/error.h>
#include <tools/qttools.h>

#include <QtCore/qobject.h>

#include <queue>
#include <unordered_map>

QT_BEGIN_NAMESPACE
class QTimer;
QT_END_NAMESPACE

namespace qbs {
class ProcessResult;

namespace Internal {
class ExecutorJob;
class FileTime;
class InputArtifactScannerContext;
class ProductInstaller;
class ProgressObserver;
class RuleNode;

class Executor : public QObject, private BuildGraphVisitor
{
    Q_OBJECT

public:
    void build();

    Executor(Logger logger, QObject *parent = nullptr);
    ~Executor() override;

    void setProject(const TopLevelProjectPtr &project);
    void setProducts(const std::vector<ResolvedProductPtr> &productsToBuild);
    void setBuildOptions(const BuildOptions &buildOptions);
    void setProgressObserver(ProgressObserver *observer) { m_progressObserver = observer; }

    ErrorInfo error() const { return m_error; }

signals:
    void reportCommandDescription(const QString &highlight, const QString &message);
    void reportProcessResult(const qbs::ProcessResult &result);

    void finished();

private:
    void onJobFinished(const qbs::ErrorInfo &err);
    void finish();
    void checkForCancellation();

    // BuildGraphVisitor implementation
    bool visit(Artifact *artifact) override;
    bool visit(RuleNode *ruleNode) override;

    enum ExecutorState { ExecutorIdle, ExecutorRunning, ExecutorCanceling };

    struct ComparePriority
    {
        bool operator() (const BuildGraphNode *x, const BuildGraphNode *y) const;
    };

    using Leaves = std::priority_queue<BuildGraphNode *, std::vector<BuildGraphNode *>,
                                       ComparePriority>;

    void doBuild();
    void prepareAllNodes();
    void syncFileDependencies();
    void prepareArtifact(Artifact *artifact);
    void setupForBuildingSelectedFiles(const BuildGraphNode *node);
    void prepareReachableNodes();
    void prepareReachableNodes_impl(BuildGraphNode *node);
    void prepareProducts();
    void setupRootNodes();
    void initLeaves();
    void updateLeaves(const NodeSet &nodes);
    void updateLeaves(BuildGraphNode *node, NodeSet &seenNodes);
    bool scheduleJobs();
    void buildArtifact(Artifact *artifact);
    void executeRuleNode(RuleNode *ruleNode);
    void finishJob(ExecutorJob *job, bool success);
    void finishNode(BuildGraphNode *leaf);
    void finishArtifact(Artifact *artifact);
    void setState(ExecutorState);
    void addExecutorJobs();
    void cancelJobs();
    void setupProgressObserver();
    void doSanityChecks();
    void handleError(const ErrorInfo &error);
    void rescueOldBuildData(Artifact *artifact, bool *childrenAdded);
    bool checkForUnbuiltDependencies(Artifact *artifact);
    void potentiallyRunTransformer(const TransformerPtr &transformer);
    void runTransformer(const TransformerPtr &transformer);
    void finishTransformer(const TransformerPtr &transformer);
    void possiblyInstallArtifact(const Artifact *artifact);
    void checkForUnbuiltProducts();
    bool checkNodeProduct(BuildGraphNode *node);

    bool mustExecuteTransformer(const TransformerPtr &transformer) const;
    bool isUpToDate(Artifact *artifact) const;
    void retrieveSourceFileTimestamp(Artifact *artifact) const;
    FileTime recursiveFileTime(const QString &filePath) const;
    QString configString() const;
    bool transformerHasMatchingOutputTags(const TransformerConstPtr &transformer) const;
    bool artifactHasMatchingOutputTags(const Artifact *artifact) const;
    bool transformerHasMatchingInputFiles(const TransformerConstPtr &transformer) const;

    void setupJobLimits();
    void updateJobCounts(const Transformer *transformer, int diff);
    bool schedulingBlockedByJobLimit(const BuildGraphNode *node);

    using JobMap = QHash<ExecutorJob *, TransformerPtr>;
    JobMap m_processingJobs;

    ProductInstaller *m_productInstaller;
    RulesEvaluationContextPtr m_evalContext;
    BuildOptions m_buildOptions;
    Logger m_logger;
    ProgressObserver *m_progressObserver;
    QList<ExecutorJob*> m_availableJobs;
    ExecutorState m_state;
    TopLevelProjectPtr m_project;
    std::vector<ResolvedProductPtr> m_productsToBuild;
    std::vector<ResolvedProductPtr> m_allProducts;
    std::unordered_map<QString, const ResolvedProduct *> m_productsByName;
    std::unordered_map<QString, const ResolvedProject *> m_projectsByName;
    std::unordered_map<QString, int> m_jobCountPerPool;
    std::unordered_map<const ResolvedProduct *, JobLimits> m_jobLimitsPerProduct;
    std::unordered_map<const Rule *, int> m_pendingTransformersPerRule;
    NodeSet m_roots;
    Leaves m_leaves;
    InputArtifactScannerContext *m_inputArtifactScanContext;
    ErrorInfo m_error;
    bool m_explicitlyCanceled = false;
    FileTags m_activeFileTags;
    FileTags m_tagsOfFilesToConsider;
    FileTags m_tagsNeededForFilesToConsider;
    QList<ResolvedProductPtr> m_productsOfFilesToConsider;
    QTimer * const m_cancelationTimer;
    QStringList m_artifactsRemovedFromDisk;
    bool m_partialBuild = false;
    qint64 m_elapsedTimeRules = 0;
    qint64 m_elapsedTimeScanners = 0;
    qint64 m_elapsedTimeInstalling = 0;
};

} // namespace Internal
} // namespace qbs

#endif // QBS_BUILDGRAPHEXECUTOR_H