Copy the entity when we return it.

Otherwise we easily end up copying it and then have an entity that
points into nowhere. Callback -> no copy, no callback -> copy.

3 files changed, 25 insertions, 4 deletions

diff --git a/common/entitybuffer.h b/common/entitybuffer.h
index 4162605..d73a138 100644
--- a/common/entitybuffer.h
+++ b/common/entitybuffer.h
@@ -12,7 +12,18 @@ struct Entity;
 class SINK_EXPORT EntityBuffer
 {
 public:
+    /**
+     * Creates an entity buffer from @param dataValue.
+     *
+     * Note that @param dataValue will need to remain valid and the data is not copied.
+     */
     EntityBuffer(const void *dataValue, int size);
+
+    /**
+     * Creates an entity buffer from @param data.
+     *
+     * Note that @param data will need to remain valid and the data is not copied.
+     */
     EntityBuffer(const QByteArray &data);
     const uint8_t *resourceBuffer();
     const uint8_t *metadataBuffer();
diff --git a/common/storage/entitystore.cpp b/common/storage/entitystore.cpp
index 638be6e..4560b13 100644
--- a/common/storage/entitystore.cpp
+++ b/common/storage/entitystore.cpp
@@ -249,7 +249,7 @@ bool EntityStore::add(const QByteArray &type, ApplicationDomain::ApplicationDoma
 
 ApplicationDomain::ApplicationDomainType EntityStore::applyDiff(const QByteArray &type, const ApplicationDomain::ApplicationDomainType &current, const ApplicationDomain::ApplicationDomainType &diff, const QByteArrayList &deletions) const
 {
-    auto newEntity = *ApplicationDomain::ApplicationDomainType::getInMemoryRepresentation<ApplicationDomain::ApplicationDomainType>(current, current.availableProperties());
+    auto newEntity = *ApplicationDomainType::getInMemoryRepresentation<ApplicationDomainType>(current, current.availableProperties());
 
     SinkTraceCtx(d->logCtx) << "Modified entity: " << newEntity;
 
@@ -512,7 +512,7 @@ ApplicationDomain::ApplicationDomainType EntityStore::readLatest(const QByteArra
 {
     ApplicationDomain::ApplicationDomainType dt;
     readLatest(type, uid, [&](const ApplicationDomain::ApplicationDomainType &entity) {
-        dt = entity;
+        dt = *ApplicationDomainType::getInMemoryRepresentation<ApplicationDomainType>(entity, entity.availableProperties());
     });
     return dt;
 }
@@ -539,7 +539,7 @@ ApplicationDomain::ApplicationDomainType EntityStore::readEntity(const QByteArra
 {
     ApplicationDomain::ApplicationDomainType dt;
     readEntity(type, uid, [&](const ApplicationDomain::ApplicationDomainType &entity) {
-        dt = entity;
+        dt = *ApplicationDomainType::getInMemoryRepresentation<ApplicationDomainType>(entity, entity.availableProperties());
     });
     return dt;
 }
@@ -601,7 +601,7 @@ ApplicationDomain::ApplicationDomainType EntityStore::readPrevious(const QByteAr
 {
     ApplicationDomain::ApplicationDomainType dt;
     readPrevious(type, uid, revision, [&](const ApplicationDomain::ApplicationDomainType &entity) {
-        dt = entity;
+        dt = *ApplicationDomainType::getInMemoryRepresentation<ApplicationDomainType>(entity, entity.availableProperties());
     });
     return dt;
 }
diff --git a/common/storage/entitystore.h b/common/storage/entitystore.h
index 003a2ca..c89c095 100644
--- a/common/storage/entitystore.h
+++ b/common/storage/entitystore.h
@@ -39,6 +39,8 @@ public:
     EntityStore(const ResourceContext &resourceContext, const Sink::Log::Context &);
     ~EntityStore() = default;
 
+    using ApplicationDomainType = ApplicationDomain::ApplicationDomainType;
+
     void initialize();
 
     //Only the pipeline may call the following functions outside of tests
@@ -63,10 +65,14 @@ public:
         return indexLookup(ApplicationDomain::getTypeName<EntityType>(), PropertyType::name, value, callback);
     }
 
+    ///Returns the uid and buffer. Note that the memory only remains valid until the next operation or transaction end.
     void readLatest(const QByteArray &type, const QByteArray &uid, const std::function<void(const QByteArray &uid, const EntityBuffer &entity)> callback);
+    ///Returns an entity. Note that the memory only remains valid until the next operation or transaction end.
     void readLatest(const QByteArray &type, const QByteArray &uid, const std::function<void(const ApplicationDomain::ApplicationDomainType &entity)> callback);
+    ///Returns an entity and operation. Note that the memory only remains valid until the next operation or transaction end.
     void readLatest(const QByteArray &type, const QByteArray &uid, const std::function<void(const ApplicationDomain::ApplicationDomainType &entity, Sink::Operation)> callback);
 
+    ///Returns a copy
     ApplicationDomain::ApplicationDomainType readLatest(const QByteArray &type, const QByteArray &uid);
 
     template<typename T>
@@ -74,8 +80,11 @@ public:
         return T(readLatest(ApplicationDomain::getTypeName<T>(), uid));
     }
 
+    ///Returns the uid and buffer. Note that the memory only remains valid until the next operation or transaction end.
     void readEntity(const QByteArray &type, const QByteArray &uid, const std::function<void(const QByteArray &uid, const EntityBuffer &entity)> callback);
+    ///Returns an entity. Note that the memory only remains valid until the next operation or transaction end.
     void readEntity(const QByteArray &type, const QByteArray &uid, const std::function<void(const ApplicationDomain::ApplicationDomainType &entity)> callback);
+    ///Returns a copy
     ApplicationDomain::ApplicationDomainType readEntity(const QByteArray &type, const QByteArray &key);
 
     template<typename T>
@@ -86,6 +95,7 @@ public:
 
     void readPrevious(const QByteArray &type, const QByteArray &uid, qint64 revision, const std::function<void(const QByteArray &uid, const EntityBuffer &entity)> callback);
     void readPrevious(const QByteArray &type, const QByteArray &uid, qint64 revision, const std::function<void(const ApplicationDomain::ApplicationDomainType &entity)> callback);
+    ///Returns a copy
     ApplicationDomain::ApplicationDomainType readPrevious(const QByteArray &type, const QByteArray &uid, qint64 revision);
 
     template<typename T>