Fix transfers (without mixins)

Fix Blockchain::get_tx_outputs_gindexs() to return amount output
indices.

Implement BlockchainLMDB::get_tx_amount_output_indices() and call it
from the function instead of BlockchainLMDB::get_tx_output_indices()

Previously, Blockchain::get_tx_outputs_gindexs() was instead returning
global output indices, which are internal to LMDB databases.

Allows bitmonerod RPC /get_o_indexes.bin to return the amount output
indices as expected.

Allows simplewallet refresh to set correct amount output indices for
incoming transfers. simplewallet can now construct and send valid
transactions (currently only without mixins).

This is a fix that doesn't require altering the structure of the
current LMDB databases.

TODO:

This can be done more efficiently by adding another LMDB database
(key-value table).

It's not used during regular transaction validation by bitmonerod. I
think it's currently used only or mainly by simplewallet for just its
own incoming transactions. So the current behavior is not a primary
bottleneck.

Currently, it's using the "output_amounts" database, walking through a
given amount's list of values, comparing each one to a given global
output index. The iteration number of the match is the desired result:
the amount output index. This is done for each global output index of
the transaction.

A tx's amount output indices can be stored in various other ways
allowing for faster lookup. Since a tx is only written once, there are
no special future write requirements for its list of indices.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/cryptonote_core/blockchain_db.h b/src/cryptonote_core/blockchain_db.h
index a3c7bc26b..b498320ae 100644
--- a/src/cryptonote_core/blockchain_db.h
+++ b/src/cryptonote_core/blockchain_db.h
@@ -452,6 +452,9 @@ public:
   // return a vector of indices corresponding to the global output index for
   // each output in the transaction with hash <h>
   virtual std::vector<uint64_t> get_tx_output_indices(const crypto::hash& h) const = 0;
+  // return a vector of indices corresponding to the amount output index for
+  // each output in the transaction with hash <h>
+  virtual std::vector<uint64_t> get_tx_amount_output_indices(const crypto::hash& h) const = 0;
 
   // returns true if key image <img> is present in spent key images storage
   virtual bool has_key_image(const crypto::key_image& img) const = 0;