| 1 | /* -*- C++ -*- |
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| 2 | This file implements the DependencyPolicy class. |
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| 3 | |
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| 4 | SPDX-FileCopyrightText: 2004-2013 Mirko Boehm <mirko@kde.org> |
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| 5 | |
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| 6 | SPDX-License-Identifier: LGPL-2.0-or-later |
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| 7 | |
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| 8 | $Id: DebuggingAids.cpp 20 2005-08-08 21:02:51Z mirko $ |
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| 9 | */ |
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| 10 | |
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| 11 | #ifndef DEPENDENCYPOLICY_H |
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| 12 | #define DEPENDENCYPOLICY_H |
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| 13 | |
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| 14 | #include <QtGlobal> |
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| 15 | |
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| 16 | // template <typename T> class QList; |
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| 17 | |
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| 18 | #include "queuepolicy.h" |
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| 19 | |
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| 20 | namespace ThreadWeaver |
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| 21 | { |
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| 22 | class JobInterface; |
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| 23 | class Dependency; |
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| 24 | |
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| 25 | /** @brief DependencyPolicy implements execution-time dependencies dependencies between Jobs. |
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| 26 | * |
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| 27 | * To declare that Job B can only be executed when Job A is finished, call addDependency. |
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| 28 | * |
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| 29 | * Be aware of circular dependencies. All dependencies on a Job will be removed if the Job object is destructed. |
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| 30 | * Sequence uses dependencies to implement the ordered execution of the sequence elements. |
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| 31 | */ |
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| 32 | class THREADWEAVER_EXPORT DependencyPolicy : public QueuePolicy |
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| 33 | { |
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| 34 | public: |
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| 35 | /** Destructor. */ |
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| 36 | ~DependencyPolicy() override; |
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| 37 | |
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| 38 | /** @brief Add jobB as a dependency of jobA. |
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| 39 | * jobA will only be executed after jobB has been successfully processed. |
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| 40 | * @param jobA the depending job |
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| 41 | * @param jobB the job jobA depends on |
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| 42 | */ |
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| 43 | void addDependency(JobPointer jobA, JobPointer jobB); |
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| 44 | void addDependency(const Dependency &dep); |
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| 45 | |
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| 46 | /** @brief Remove a dependency. |
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| 47 | * The dependency of jobA on jobB is removed. If no dependencies are left for jobA, canRun will return true. |
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| 48 | * Returns false if the given object is not dependency of this job. |
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| 49 | * @param jobA the depending job |
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| 50 | * @param jobB the job jobA depends on |
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| 51 | * @return true if dependency existed, false otherwise |
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| 52 | */ |
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| 53 | bool removeDependency(JobPointer jobA, JobPointer jobB); |
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| 54 | bool removeDependency(const Dependency &dep); |
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| 55 | |
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| 56 | /** @brief Resolve all dependencies for a job. |
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| 57 | * This method is called after the Job has been finished, or when it is deleted without being executed (performed by the |
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| 58 | * destructor). The method will remove all entries stating that another Job depends on this one. |
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| 59 | */ |
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| 60 | void resolveDependencies(JobPointer); |
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| 61 | |
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| 62 | // FIXME remove |
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| 63 | // /** @brief Retrieve a list of dependencies of this job. */ |
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| 64 | // QList<JobPointer> getDependencies(JobPointer) const; |
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| 65 | |
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| 66 | static DependencyPolicy &instance(); |
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| 67 | |
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| 68 | bool canRun(JobPointer) override; |
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| 69 | |
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| 70 | void free(JobPointer) override; |
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| 71 | |
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| 72 | void release(JobPointer) override; |
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| 73 | |
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| 74 | void destructed(JobInterface *job) override; |
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| 75 | |
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| 76 | bool isEmpty() const; |
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| 77 | |
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| 78 | protected: |
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| 79 | /** @brief Query whether the job has an unresolved dependency. |
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| 80 | * In case it does, the policy will return false from canRun(). |
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| 81 | */ |
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| 82 | bool hasUnresolvedDependencies(JobPointer) const; |
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| 83 | |
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| 84 | private: |
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| 85 | DependencyPolicy(); |
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| 86 | class Private; |
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| 87 | Private *const d; |
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| 88 | }; |
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| 89 | |
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| 90 | } |
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| 91 | |
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| 92 | #endif |
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| 93 | |
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