Async: initial support for native chaining of KJobs

It is now possible use KJob-derived jobs with libasync without having to write
lambda wrappers.

auto job = Async::start<ReturnType, MyKJob, MyKJob::result, Args ...)
           .then<ReturnType, OtherKJob, OtherKJob::result, PrevKJobReturnType>();

job.exec(arg1, arg2, ...);

The reason for this approach (instead of taking KJob* as an argument is that
we usually want the KJob ctor arguments to depend on result of previous job.
At least in case of Async::start() however it makes sense to support passing
KJob* as an argument (not yet implemented).

In future we should also support custom error handlers.

The KJob integration is build-time optional, but enabled by default (pass
-DWITH_KJOB=FALSE to CMake to disable).

Adds KCoreAddons dependency.

1 files changed, 28 insertions, 0 deletions

diff --git a/async/autotests/testkjob.cpp b/async/autotests/testkjob.cpp
new file mode 100644
index 0000000..b86f913
--- /dev/null
+++ b/async/autotests/testkjob.cpp
@@ -0,0 +1,28 @@
+#include "testkjob.h"
+
+TestKJob::TestKJob(int result)
+    : mResult(result)
+{
+    connect(&mTimer, &QTimer::timeout,
+            this, &TestKJob::onTimeout);
+    mTimer.setSingleShot(true);
+    mTimer.setInterval(200);
+}
+
+TestKJob::~TestKJob()
+{}
+
+void TestKJob::start()
+{
+    mTimer.start();
+}
+
+int TestKJob::result()
+{
+    return mResult;
+}
+
+void TestKJob::onTimeout()
+{
+    emitResult();
+}
\ No newline at end of file