TaskTree: Add a possibility to setup storage handlers

Storage handlers make it possible to pass initial data
into task tree and make it possible to retrieve the output
data from task tree after the task tree finished.

Change-Id: I0bcc12f5e552f55c1d5d89b81521ae9cb7b8b124
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/libs/utils/tasktree.h

@@ -13,6 +13,8 @@ namespace Utils {
 
 class TaskContainer;
 
+class TaskTreePrivate;
+
 namespace Tasking {
 
 class QTCREATOR_UTILS_EXPORT TaskInterface : public QObject
@@ -59,6 +61,7 @@ private:
     };
     QSharedPointer<StorageData> m_storageData;
     friend TaskContainer;
+    friend TaskTreePrivate;
 };
 
 inline size_t qHash(const TreeStorageBase &storage, uint seed = 0)
@@ -312,10 +315,22 @@ public:
     void start();
     void stop();
     bool isRunning() const;
+
     int taskCount() const;
     int progressMaximum() const { return taskCount(); }
     int progressValue() const; // all finished / skipped / stopped tasks, groups itself excluded
 
+    template <typename StorageStruct, typename StorageHandler>
+    void onStorageSetup(const Tasking::TreeStorage<StorageStruct> &storage,
+                        const StorageHandler &handler) {
+        setupStorageHandler(storage, wrapHandler<StorageStruct>(handler), {});
+    }
+    template <typename StorageStruct, typename StorageHandler>
+    void onStorageDone(const Tasking::TreeStorage<StorageStruct> &storage,
+                       const StorageHandler &handler) {
+        setupStorageHandler(storage, {}, wrapHandler<StorageStruct>(handler));
+    }
+
 signals:
     void started();
     void done();
@@ -323,6 +338,21 @@ signals:
     void progressValueChanged(int value); // updated whenever task finished / skipped / stopped
 
 private:
+    using StorageVoidHandler = std::function<void(void *)>;
+    void setupStorageHandler(const Tasking::TreeStorageBase &storage,
+                             StorageVoidHandler setupHandler,
+                             StorageVoidHandler doneHandler);
+    template <typename StorageStruct>
+    StorageVoidHandler wrapHandler(const std::function<void(StorageStruct *)> &handler) {
+        if (!handler)
+            return {};
+        return [handler](void *voidStruct) {
+            StorageStruct *storageStruct = static_cast<StorageStruct *>(voidStruct);
+            handler(storageStruct);
+        };
+    }
+
+    friend class TaskTreePrivate;
     TaskTreePrivate *d;
 };