From 9f3a6ff5d27e4983ee626231e43210d2bbb95dd6 Mon Sep 17 00:00:00 2001
From: Christian Mollekopf <chrigi_1@fastmail.fm>
Date: Fri, 14 Aug 2015 17:11:40 +0200
Subject: Almost working batch dequeues

---
 common/messagequeue.cpp | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

(limited to 'common/messagequeue.cpp')

diff --git a/common/messagequeue.cpp b/common/messagequeue.cpp
index 84385ca..598c63a 100644
--- a/common/messagequeue.cpp
+++ b/common/messagequeue.cpp
@@ -61,6 +61,56 @@ void MessageQueue::dequeue(const std::function<void(void *ptr, int size, std::fu
     }
 }
 
+KAsync::Job<void> MessageQueue::dequeueBatch(int maxBatchSize, const std::function<void(void *ptr, int size, std::function<void(bool success)>)> &resultHandler)
+{
+    auto resultCount = QSharedPointer<int>::create(0);
+    auto keyList = QSharedPointer<QByteArrayList>::create();
+    return KAsync::start<void>([this, maxBatchSize, resultHandler, resultCount, keyList](KAsync::Future<void> &future) {
+        bool readValue = false;
+        int count = 0;
+        mStorage.createTransaction(Akonadi2::Storage::ReadOnly).scan("", [this, resultHandler, &readValue, resultCount, keyList, &count, maxBatchSize](const QByteArray &key, const QByteArray &value) -> bool {
+            if (Akonadi2::Storage::isInternalKey(key)) {
+                return true;
+            }
+            readValue = true;
+            //We need a copy of the key here, otherwise we can't store it in the lambda (the pointers will become invalid)
+            keyList->append(QByteArray(key.constData(), key.size()));
+            resultHandler(const_cast<void*>(static_cast<const void*>(value.data())), value.size(), [this, resultCount, keyList, &count](bool success) {
+                *resultCount += 1;
+                //We're done
+                //FIXME the check below should only be done once we finished reading
+                if (*resultCount >= count) {
+                    //FIXME do this from the caller thread
+                    auto transaction = std::move(mStorage.createTransaction(Akonadi2::Storage::ReadWrite));
+                    for (const auto &key : *keyList) {
+                        transaction.remove(key, [key](const Akonadi2::Storage::Error &error) {
+                            ErrorMsg() << "Error while removing value" << error.message << key;
+                            //Don't call the errorhandler in here, we already called the result handler
+                        });
+                    }
+                    if (isEmpty()) {
+                        emit this->drained();
+                    }
+                }
+            });
+            count++;
+            if (count <= maxBatchSize) {
+                return true;
+            }
+            return false;
+        },
+        [](const Akonadi2::Storage::Error &error) {
+            ErrorMsg() << "Error while retrieving value" << error.message;
+            // errorHandler(Error(error.store, error.code, error.message));
+        }
+        );
+        if (!readValue) {
+            future.setError(-1, "No message found");
+            future.setFinished();
+        }
+    });
+}
+
 bool MessageQueue::isEmpty()
 {
     int count = 0;
-- 
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