Added Async::dowhile

2 files changed, 48 insertions, 0 deletions

diff --git a/async/autotests/asynctest.cpp b/async/autotests/asynctest.cpp
index 85f5ea5..a387dd6 100644
--- a/async/autotests/asynctest.cpp
+++ b/async/autotests/asynctest.cpp
@@ -68,6 +68,8 @@ private Q_SLOTS:
     void testLifetimeWithoutHandle();
     void testLifetimeWithHandle();
 
+    void testWhile();
+
     void benchmarkSyncThenExecutor();
 
 private:
@@ -377,6 +379,23 @@ void AsyncTest::testVoidEach()
     QCOMPARE(check, expected);
 }
 
+void AsyncTest::testWhile()
+{
+
+    QList<int> processed;
+    QList<int> list({1, 2, 3, 4});
+    auto it = QSharedPointer<QListIterator<int> >::create(list);
+    Async::dowhile<void>(
+        [it]() -> bool { return it->hasNext(); },
+        [it, &processed](Async::Future<void> future) {
+            auto value = it->next();
+            processed << value;
+            future.setFinished();
+        }
+    ).exec().waitForFinished();
+    QCOMPARE(processed, list);
+}
+
 
 
 
diff --git a/async/src/async.h b/async/src/async.h
index 8f6457b..0d1d81e 100644
--- a/async/src/async.h
+++ b/async/src/async.h
@@ -85,6 +85,7 @@ template<typename Out, typename In>
 using SyncReduceTask = typename detail::identity<std::function<Out(In)>>::type;
 
 using ErrorHandler = std::function<void(int, const QString &)>;
+using Condition = std::function<bool()>;
 
 namespace Private
 {
@@ -226,6 +227,9 @@ template<typename ReturnType, typename KJobType, ReturnType (KJobType::*KJobResu
 Job<ReturnType, Args ...> start();
 #endif
 
+template<typename Out>
+Job<Out> dowhile(Condition condition, ThenTask<void> func);
+
 
 /**
  * A null job.
@@ -507,6 +511,31 @@ Job<ReturnType, Args ...> start()
 }
 #endif
 
+static void asyncWhile(const std::function<void(std::function<void(bool)>)> &body, const std::function<void()> &completionHandler) {
+    body([body, completionHandler](bool complete) {
+        if (complete) {
+            completionHandler();
+        } else {
+            asyncWhile(body, completionHandler);
+        }
+    });
+}
+    }
+template<typename Out>
+Job<Out> dowhile(Condition condition, ThenTask<void> body)
+{
+    return Async::start<void>([body, condition](Async::Future<void> &future) {
+        asyncWhile([condition, body](std::function<void(bool)> whileCallback) {
+            Async::start<void>(body).then<void>([whileCallback, condition]() {
+                whileCallback(!condition());
+            }).exec();
+        },
+        [&future]() { //while complete
+            future.setFinished();
+        });
+    });
+}
+
 template<typename Out>
 Job<Out> null()
 {