[Sync] Initial support for encrypting any datatype (no UI hookup yet).

chrome/browser/sync/syncable/syncable.h

Index: chrome/browser/sync/syncable/syncable.h
diff --git a/chrome/browser/sync/syncable/syncable.h b/chrome/browser/sync/syncable/syncable.h
index ba4611559fc5a6ddc7df6dfb7c81967df855e3cf..90f9def6488acf82f105b47699d38d4b2f421fe5 100644
--- a/chrome/browser/sync/syncable/syncable.h
+++ b/chrome/browser/sync/syncable/syncable.h
@@ -791,6 +791,12 @@ class Directory {
       const std::string& dir_name,
       const FilePath& backing_filepath);
 
+  // Update this directory's set of encrypted datatypes.
+  // Note: |types| should be a complete set of all datatypes that require
+  // encryption, not just a subset. This does not actually perform any
+  // encryption or modify the Nigori node.
+  void SetEncryptedDataTypes(const ModelTypeSet& encrypted_types);
+
  private:
   // These private versions expect the kernel lock to already be held
   // before calling.
@@ -1021,6 +1027,12 @@ class Directory {
     // The next metahandle is protected by kernel mutex.
     int64 next_metahandle;
 
+    // The set of all datatypes that currently require encryption. This is
+    // set when we load the nigori node and modified anytime we either receive
+    // a change to the nigori node or through the local user changing the
+    // encryption status.
+    ModelTypeSet encrypted_datatypes;

[tim (not reviewing), 2011/02/11 06:52:31]

Why do we store this in 3 places again?  The fact that we have to keep 3
replicas in sync freaks me out :(  Can we eliminate at least one of them?
Reading the nigori node is pretty quick...

[Nicolas Zea, 2011/02/14 21:18:41]

Done.

+
     // Keep a history of recently flushed metahandles for debugging
     // purposes.  Protected by the save_changes_mutex.
     DebugQueue<int64, 1000> flushed_metahandles;
@@ -1048,8 +1060,18 @@ class BaseTransaction {
   inline Directory* directory() const { return directory_; }
   inline Id root_id() const { return Id(); }
 
+  inline const ModelTypeSet& GetEncryptedDatatypes() {
+    return dirkernel_->encrypted_datatypes;
+  }
+
   virtual ~BaseTransaction();
 
+  // Update this transaction's directory's set of encrypted datatypes.
+  // Note: |encrypted_types| should be a complete set of all datatypes that
+  // require encryption, not just a subset. This does not actually perform any
+  // encryption or modify the Nigori node.
+  void SetEncryptedDataTypes(const ModelTypeSet& encrypted_types);

[tim (not reviewing), 2011/02/11 06:52:31]

Why have get/set operations on the transaction when you can get the directory,
which is where these forward to?

[Nicolas Zea, 2011/02/14 21:18:41]

Done.

+
  protected:
   BaseTransaction(Directory* directory, const char* name,
                   const char* source_file, int line, WriterTag writer);