From c55054e899660f2d667af2c2e573a1267d47358e Mon Sep 17 00:00:00 2001
From: Christian Mollekopf <chrigi_1@fastmail.fm>
Date: Mon, 13 Apr 2015 20:15:14 +0200
Subject: Use a queryrunner to execute queries.

The queryrunner is responsible for running queries and keeping them
up to date. This is required for self-updating queries.

To get this to work properly the ResultProvider/emitter had to be fixed.
The emitter now only lives as long as the client holds a reference to
it, allowing the provider to detect when it is no longer necessary to
keep the query alive (because noone is listening).

In the process various lifetime issues have been fixed, that we're
caused by lambdas capturing smartpointers, that then extended the
lifetime of the associated objects unpredictably.
---
 dummyresource/facade.cpp | 44 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 41 insertions(+), 3 deletions(-)

(limited to 'dummyresource/facade.cpp')

diff --git a/dummyresource/facade.cpp b/dummyresource/facade.cpp
index 1477fcf..f603c56 100644
--- a/dummyresource/facade.cpp
+++ b/dummyresource/facade.cpp
@@ -147,15 +147,51 @@ void DummyResourceFacade::readValue(QSharedPointer<Akonadi2::Storage> storage, c
     });
 }
 
-Async::Job<void> DummyResourceFacade::load(const Akonadi2::Query &query, const std::function<void(const Akonadi2::ApplicationDomain::Event::Ptr &)> &resultCallback)
+Async::Job<void> DummyResourceFacade::load(const Akonadi2::Query &query, const QSharedPointer<Akonadi2::ResultProvider<Akonadi2::ApplicationDomain::Event::Ptr> > &resultProvider)
 {
-    return synchronizeResource(query.syncOnDemand, query.processAll).then<void>([=](Async::Future<void> &future) {
+    auto runner = QSharedPointer<QueryRunner>::create(query);
+    //The runner only lives as long as the resultProvider
+    resultProvider->setQueryRunner(runner);
+    runner->setQuery([this, resultProvider, query](qint64 oldRevision, qint64 newRevision) -> Async::Job<qint64> {
+        return Async::start<qint64>([this, resultProvider, query](Async::Future<qint64> &future) {
+            //TODO only emit changes and don't replace everything
+            resultProvider->clear();
+            //rerun query
+            std::function<void(const Akonadi2::ApplicationDomain::Event::Ptr &)> addCallback = std::bind(&Akonadi2::ResultProvider<Akonadi2::ApplicationDomain::Event::Ptr>::add, resultProvider, std::placeholders::_1);
+            load(query, addCallback).then<void, qint64>([resultProvider, &future](qint64 queriedRevision) {
+                //TODO set revision in result provider?
+                //TODO update all existing results with new revision
+                resultProvider->complete();
+                future.setValue(queriedRevision);
+                future.setFinished();
+            }).exec();
+        });
+    });
+
+    auto resourceAccess = mResourceAccess;
+    //TODO we need to somehow disconnect this
+    QObject::connect(resourceAccess.data(), &Akonadi2::ResourceAccess::revisionChanged, [runner](qint64 newRevision) {
+        runner->revisionChanged(newRevision);
+    });
+
+    return Async::start<void>([runner](Async::Future<void> &future) {
+        runner->run().then<void>([&future]() {
+            //TODO if not live query, destroy runner.
+            future.setFinished();
+        }).exec();
+    });
+}
+
+Async::Job<qint64> DummyResourceFacade::load(const Akonadi2::Query &query, const std::function<void(const Akonadi2::ApplicationDomain::Event::Ptr &)> &resultCallback)
+{
+    return synchronizeResource(query.syncOnDemand, query.processAll).then<qint64>([=](Async::Future<qint64> &future) {
         //Now that the sync is complete we can execute the query
         const auto preparedQuery = prepareQuery(query);
 
         auto storage = QSharedPointer<Akonadi2::Storage>::create(Akonadi2::Store::storageLocation(), "org.kde.dummy");
 
-        //TODO use transaction over full query and record store revision. We'll need it to update the query.
+        storage->startTransaction(Akonadi2::Storage::ReadOnly);
+        const qint64 revision = storage->maxRevision();
 
         //Index lookups
         QVector<QByteArray> keys;
@@ -177,6 +213,8 @@ Async::Job<void> DummyResourceFacade::load(const Akonadi2::Query &query, const s
                 readValue(storage, key, resultCallback, preparedQuery);
             }
         }
+        storage->abortTransaction();
+        future.setValue(revision);
         future.setFinished();
     });
 }
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