[USS] Implement SharedModelTypeProcessor::GetAllNodes for USS

components/sync/core/shared_model_type_processor.cc

Index: components/sync/core/shared_model_type_processor.cc
diff --git a/components/sync/core/shared_model_type_processor.cc b/components/sync/core/shared_model_type_processor.cc
index 14ca2b6e9825f7b3be65115448e95f92fa4b38eb..65b9df6eb5b411f9ff2c94132c84599409d384dd 100644
--- a/components/sync/core/shared_model_type_processor.cc
+++ b/components/sync/core/shared_model_type_processor.cc
@@ -15,6 +15,7 @@
 #include "components/sync/core/activation_context.h"
 #include "components/sync/core/processor_entity_tracker.h"
 #include "components/sync/engine/commit_queue.h"
+#include "components/sync/protocol/proto_value_conversions.h"
 #include "components/sync/syncable/syncable_util.h"
 
 namespace syncer_v2 {
@@ -191,6 +192,16 @@ bool SharedModelTypeProcessor::IsConnected() const {
   return !!worker_;
 }
 
+void SharedModelTypeProcessor::GetAllNodes(
+    const scoped_refptr<base::TaskRunner>& task_runner,
+    const base::Callback<void(const syncer::ModelType,
+                              std::unique_ptr<base::ListValue>)>& callback) {
+  DCHECK(service_);
+  service_->GetAllData(
+      base::Bind(&SharedModelTypeProcessor::MergeDataWithMetadata,
+                 base::Unretained(this), task_runner, callback));
+}
+
 void SharedModelTypeProcessor::DisableSync() {
   DCHECK(CalledOnValidThread());
   std::unique_ptr<MetadataChangeList> change_list =
@@ -704,4 +715,39 @@ ProcessorEntityTracker* SharedModelTypeProcessor::CreateEntity(
   return CreateEntity(service_->GetStorageKey(data), data);
 }
 
+void SharedModelTypeProcessor::MergeDataWithMetadata(
+    const scoped_refptr<base::TaskRunner>& task_runner,
+    const base::Callback<void(const syncer::ModelType,
+                              std::unique_ptr<base::ListValue>)>& callback,
+    syncer::SyncError error,
+    std::unique_ptr<DataBatch> batch) {
+  std::unique_ptr<base::ListValue> all_nodes(new base::ListValue());
+
+  while (batch->HasNext()) {
+    KeyAndData data = batch->Next();
+    std::unique_ptr<base::DictionaryValue> node =
+        EntityData::ToValue(*data.second);
+    ProcessorEntityTracker* entity = GetEntityForStorageKey(data.first);
+    // entity could be null if there are some unapplied changes.

[skym, 2016/09/12 16:40:39]

Capitalize first letter

[Gang Wu, 2016/09/12 22:38:03]

Done.

+    if (entity != nullptr) {
+      std::unique_ptr<base::DictionaryValue> metadata =
+          syncer::EntityMetadataToValue(entity->metadata());
+      node->MergeDictionary(metadata.get());

[skym, 2016/09/12 16:40:38]

1) Why do we merge these two? Why not use a single copy and ignore the other
one?
2) Who wins conflicts?

[Gang Wu, 2016/09/12 22:38:03]

|node| is real data, |metadata| is metadata, so mergeDictionary at here
shouldn't have any conflicts, hopefully.

[skym, 2016/09/13 16:45:17]

Really? Looking at EntityData::ToDictionaryValue() and EntityMetadataToValue()
they both set client_tag_hash, creation_time, modification_time.

[Gang Wu, 2016/09/13 18:45:02]

Thanks for point that out!
But in here, all the keys in node is uppercase, and all the keys in metadata is
lowercase, so still wont have any conflicts.
That also said, there will have two client_tag_hash, creation_time and
modification_time.
But since this is debug info, I think show both of them is better, what do you
think?

+    }
+    node->SetString("modelType", ModelTypeToString(type_));

[skym, 2016/09/12 16:40:39]

I know this wasn't you, but its really odd how some of these keys are camelCase
and some are SHOUTY_CASE.

[Gang Wu, 2016/09/12 22:38:03]

We can discuss this in USS meeting, since this will involve a lot of keys.

+    all_nodes->Append(std::move(node));
+  }
+
+  // Create a permanent folder for this data type

[skym, 2016/09/12 16:40:39]

Comment sentence should have a period at the end. Also, can you explain why we
do this? From the looks of this, it looks like you you're assuming we're never
going to migrate parent/root folders and that they shouldn't be in our model
representation any longer. Is that correct?

[Gang Wu, 2016/09/12 22:38:03]

yes, that is correct.
Comments added.

+  std::unique_ptr<base::DictionaryValue> rootnode(new base::DictionaryValue());

[skym, 2016/09/12 16:40:39]

MakeUnique?

[Gang Wu, 2016/09/12 22:38:03]

any different?

[skym, 2016/09/13 16:45:17]

https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/iQgMedVA8-k

[Gang Wu, 2016/09/13 18:45:02]

Done.

+  rootnode->SetString("PARENT_ID", "r");

[skym, 2016/09/12 16:40:39]

r?

[Gang Wu, 2016/09/12 22:38:03]

I guess "r" means root, isTypeRootNode in sync_node_browser.js use this to
determinate which node is root folder. I will add more comments for this
section.

+  rootnode->SetBoolean("IS_DIR", true);
+  rootnode->SetString("modelType", ModelTypeToString(type_));
+  rootnode->SetString("NON_UNIQUE_NAME", ModelTypeToString(type_));

[skym, 2016/09/12 16:40:38]

You call ModelTypeToString a lot in this function... Just saying.

[Gang Wu, 2016/09/12 22:38:03]

Done.

+  all_nodes->Append(std::move(rootnode));
+
+  task_runner->PostTask(FROM_HERE,
+                        base::Bind(callback, type_, base::Passed(&all_nodes)));
+}
+
 }  // namespace syncer_v2