From 979276a574e615213891463ab23569f7bbaf07b4 Mon Sep 17 00:00:00 2001
From: Christian Mollekopf <chrigi_1@fastmail.fm>
Date: Tue, 17 Jan 2017 20:16:25 +0100
Subject: Handle errors without crashing.

---
 common/synchronizer.cpp      | 35 +++++++++++++++++++++++------------
 common/synchronizerstore.cpp |  9 ++++++++-
 2 files changed, 31 insertions(+), 13 deletions(-)

(limited to 'common')

diff --git a/common/synchronizer.cpp b/common/synchronizer.cpp
index a341f63..cfe1f09 100644
--- a/common/synchronizer.cpp
+++ b/common/synchronizer.cpp
@@ -279,10 +279,11 @@ KAsync::Job<void> Synchronizer::processSyncQueue()
     if (mSyncRequestQueue.isEmpty() || mSyncInProgress) {
         return KAsync::null<void>();
     }
-    mSyncInProgress = true;
-    mMessageQueue->startTransaction();
 
-    auto job = KAsync::null<void>();
+    auto job = KAsync::syncStart<void>([this] {
+        mMessageQueue->startTransaction();
+        mSyncInProgress = true;
+    });
     while (!mSyncRequestQueue.isEmpty()) {
         auto request = mSyncRequestQueue.takeFirst();
         if (request.requestType == Synchronizer::SyncRequest::Synchronization) {
@@ -334,13 +335,17 @@ KAsync::Job<void> Synchronizer::processSyncQueue()
                 Sink::Commands::FinishFlushBuffer(fbb, location);
                 enqueueCommand(Sink::Commands::FlushCommand, BufferUtils::extractBuffer(fbb));
             }
-        } else {
+        } else if (request.requestType == Synchronizer::SyncRequest::ChangeReplay) {
             job = replayNextRevision();
+        } else {
+            SinkWarning() << "Unknown request type: " << request.requestType;
+            return KAsync::error(KAsync::Error{"Unknown request type."});
         }
     }
     return job.then<void>([this](const KAsync::Error &error) {
-        mSyncStore.clear();
+        mSyncTransaction.abort();
         mMessageQueue->commit();
+        mSyncStore.clear();
         mSyncInProgress = false;
         if (allChangesReplayed()) {
             emit changesReplayed();
@@ -399,6 +404,18 @@ KAsync::Job<void> Synchronizer::replay(const QByteArray &type, const QByteArray
     Sink::EntityBuffer buffer(value);
     const Sink::Entity &entity = buffer.entity();
     const auto metadataBuffer = Sink::EntityBuffer::readBuffer<Sink::Metadata>(entity.metadata());
+    if (!metadataBuffer) {
+        SinkError() << "No metadata buffer available.";
+        return KAsync::error("No metadata buffer");
+    }
+    if (mSyncTransaction) {
+        SinkError() << "Leftover sync transaction.";
+        mSyncTransaction.abort();
+    }
+    if (mSyncStore) {
+        SinkError() << "Leftover sync store.";
+        mSyncStore.clear();
+    }
     Q_ASSERT(metadataBuffer);
     Q_ASSERT(!mSyncStore);
     Q_ASSERT(!mSyncTransaction);
@@ -411,13 +428,7 @@ KAsync::Job<void> Synchronizer::replay(const QByteArray &type, const QByteArray
 
     if (operation != Sink::Operation_Creation) {
         oldRemoteId = syncStore().resolveLocalId(type, uid);
-        if (oldRemoteId.isEmpty()) {
-            SinkWarning() << "Couldn't find the remote id for: " << type << uid;
-            mSyncStore.clear();
-            mSyncTransaction.abort();
-            mEntityStore->abortTransaction();
-            return KAsync::error<void>(1, "Couldn't find the remote id.");
-        }
+        //oldRemoteId can be empty if the resource implementation didn't return a remoteid
     }
     SinkTrace() << "Replaying " << key << type << uid << oldRemoteId;
 
diff --git a/common/synchronizerstore.cpp b/common/synchronizerstore.cpp
index a9da2fe..31c1391 100644
--- a/common/synchronizerstore.cpp
+++ b/common/synchronizerstore.cpp
@@ -117,13 +117,20 @@ void SynchronizerStore::writeValue(const QByteArray &prefix, const QByteArray &k
 
 void SynchronizerStore::removeValue(const QByteArray &prefix, const QByteArray &key)
 {
-    mTransaction.openDatabase("values").remove(prefix + key, [&](const Sink::Storage::DataStore::Error &error) {
+    auto assembled = prefix + key;
+    if (assembled.isEmpty()) {
+        return;
+    }
+    mTransaction.openDatabase("values").remove(assembled, [&](const Sink::Storage::DataStore::Error &error) {
         SinkWarning() << "Failed to remove the value: " << prefix + key << error;
     });
 }
 
 void SynchronizerStore::removePrefix(const QByteArray &prefix)
 {
+    if (prefix.isEmpty()) {
+        return;
+    }
     //FIXME remove all values matching prefix
     // mTransaction.openDatabase("values").remove(prefix, [](const Sink::Storage::DataStore::Error &) {
     //     //Ignore errors because we may not find the value
-- 
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