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diff --git a/src/async/progress-splitter.h b/src/async/progress-splitter.h
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/** \file Progress-splitter
+ * Dynamically split a Progress into several sub-tasks.
+ */
+#ifndef INKSCAPE_ASYNC_PROGRESS_SPLITTER_H
+#define INKSCAPE_ASYNC_PROGRESS_SPLITTER_H
+
+#include <vector>
+#include <optional>
+#include "progress.h"
+
+namespace Inkscape {
+namespace Async {
+
+/**
+ * A RAII object for splitting a Progress into a dynamically-determined collection of sub-tasks.
+ */
+template <typename T, typename... S>
+class ProgressSplitter
+{
+public:
+    /// Construct a progress splitter for a given task.
+    ProgressSplitter(Progress<T, S...> &parent) : parent(&parent) {}
+
+    /// Add a SubProgress which makes progress \a amount.
+    ProgressSplitter &add(std::optional<SubProgress<T, S...>> &progress, T amount)
+    {
+        entries.push_back({ &progress, amount });
+        return *this;
+    }
+
+    /// Convenience method to enable a "fluent interface". Calls \a add if \a condition is true.
+    ProgressSplitter &add_if(std::optional<SubProgress<T, S...>> &progress, T amount, bool condition)
+    {
+        return condition ? add(progress, amount) : *this;
+    }
+
+    /// Assign to each added SubProgress its portion of the total progress.
+    ~ProgressSplitter() { apportion(); }
+
+private:
+    struct Entry
+    {
+        std::optional<SubProgress<T, S...>> *progress;
+        T amount;
+    };
+
+    Progress<T, S...> *parent;
+    std::vector<Entry> entries;
+
+    void apportion() noexcept
+    {
+        if (entries.empty()) {
+            return;
+        }
+
+        T total = 0;
+        for (auto const &e : entries) {
+            total += e.amount;
+        }
+
+        T from = 0;
+        for (auto &e : entries) {
+            e.progress->emplace(*parent, from / total, e.amount / total);
+            from += e.amount;
+        }
+    }
+};
+
+} // namespace Async
+} // namespace Inkscape
+
+#endif // INKSCAPE_ASYNC_PROGRESS_SPLITTER_H