add RPC to get a histogram of outputs of a given amount

src/cryptonote_core/blockchain.cpp

@@ -1903,6 +1903,45 @@ void Blockchain::get_output_key_mask_unlocked(const uint64_t& amount, const uint
   unlocked = is_tx_spendtime_unlocked(m_db->get_tx_unlock_time(toi.first));
 }
 //------------------------------------------------------------------
+bool Blockchain::get_output_distribution(uint64_t amount, uint64_t from_height, uint64_t &start_height, std::vector<uint64_t> &distribution, uint64_t &base) const
+{
+  // rct outputs don't exist before v3
+  if (amount == 0)
+  {
+    switch (m_nettype)
+    {
+      case STAGENET: start_height = stagenet_hard_forks[2].height; break;
+      case TESTNET: start_height = testnet_hard_forks[2].height; break;
+      case MAINNET: start_height = mainnet_hard_forks[2].height; break;
+      default: return false;
+    }
+  }
+  else
+    start_height = 0;
+  base = 0;
+
+  const uint64_t real_start_height = start_height;
+  if (from_height > start_height)
+    start_height = from_height;
+
+  distribution.clear();
+  uint64_t db_height = m_db->height();
+  if (start_height >= db_height)
+    return false;
+  distribution.resize(db_height - start_height, 0);
+  bool r = for_all_outputs(amount, [&](uint64_t height) {
+    CHECK_AND_ASSERT_MES(height >= real_start_height && height <= db_height, false, "Height not in expected range");
+    if (height >= start_height)
+      distribution[height - start_height]++;
+    else
+      base++;
+    return true;
+  });
+  if (!r)
+    return false;
+  return true;
+}
+//------------------------------------------------------------------
 // This function takes a list of block hashes from another node
 // on the network to find where the split point is between us and them.
 // This is used to see what to send another node that needs to sync.
@@ -4441,11 +4480,16 @@ bool Blockchain::for_all_transactions(std::function<bool(const crypto::hash&, co
   return m_db->for_all_transactions(f);
 }
 
-bool Blockchain::for_all_outputs(std::function<bool(uint64_t amount, const crypto::hash &tx_hash, size_t tx_idx)> f) const
+bool Blockchain::for_all_outputs(std::function<bool(uint64_t amount, const crypto::hash &tx_hash, uint64_t height, size_t tx_idx)> f) const
 {
   return m_db->for_all_outputs(f);;
 }
 
+bool Blockchain::for_all_outputs(uint64_t amount, std::function<bool(uint64_t height)> f) const
+{
+  return m_db->for_all_outputs(amount, f);;
+}
+
 namespace cryptonote {
 template bool Blockchain::get_transactions(const std::vector<crypto::hash>&, std::list<transaction>&, std::list<crypto::hash>&) const;
 }

src/cryptonote_core/blockchain.h

@@ -523,6 +523,17 @@ namespace cryptonote
      */
     bool get_random_rct_outs(const COMMAND_RPC_GET_RANDOM_RCT_OUTPUTS::request& req, COMMAND_RPC_GET_RANDOM_RCT_OUTPUTS::response& res) const;
 
+    /**
+     * @brief gets per block distribution of outputs of a given amount
+     *
+     * @param amount the amount to get a ditribution for
+     * @param return-by-reference from_height the height before which we do not care about the data
+     * @param return-by-reference start_height the height of the first rct output
+     * @param return-by-reference distribution the start offset of the first rct output in this block (same as previous if none)
+     * @param return-by-reference base how many outputs of that amount are before the stated distribution
+     */
+    bool get_output_distribution(uint64_t amount, uint64_t from_height, uint64_t &start_height, std::vector<uint64_t> &distribution, uint64_t &base) const;
+
     /**
      * @brief gets the global indices for outputs from a given transaction
      *
@@ -857,7 +868,17 @@ namespace cryptonote
      *
      * @return false if any output fails the check, otherwise true
      */
-    bool for_all_outputs(std::function<bool(uint64_t amount, const crypto::hash &tx_hash, size_t tx_idx)>) const;
+    bool for_all_outputs(std::function<bool(uint64_t amount, const crypto::hash &tx_hash, uint64_t height, size_t tx_idx)>) const;
+
+    /**
+     * @brief perform a check on all outputs of a given amount in the blockchain
+     *
+     * @param amount the amount to iterate through
+     * @param std::function the check to perform, pass/fail
+     *
+     * @return false if any output fails the check, otherwise true
+     */
+    bool for_all_outputs(uint64_t amount, std::function<bool(uint64_t height)>) const;
 
     /**
      * @brief get a reference to the BlockchainDB in use by Blockchain

src/cryptonote_core/cryptonote_core.cpp

@@ -1105,6 +1105,11 @@ namespace cryptonote
     return m_blockchain_storage.get_random_rct_outs(req, res);
   }
   //-----------------------------------------------------------------------------------------------
+  bool core::get_output_distribution(uint64_t amount, uint64_t from_height, uint64_t &start_height, std::vector<uint64_t> &distribution, uint64_t &base) const
+  {
+    return m_blockchain_storage.get_output_distribution(amount, from_height, start_height, distribution, base);
+  }
+  //-----------------------------------------------------------------------------------------------
   bool core::get_tx_outputs_gindexs(const crypto::hash& tx_id, std::vector<uint64_t>& indexs) const
   {
     return m_blockchain_storage.get_tx_outputs_gindexs(tx_id, indexs);

src/cryptonote_core/cryptonote_core.h

@@ -571,6 +571,12 @@ namespace cryptonote
       */
      bool get_random_rct_outs(const COMMAND_RPC_GET_RANDOM_RCT_OUTPUTS::request& req, COMMAND_RPC_GET_RANDOM_RCT_OUTPUTS::response& res) const;
 
+     /**
+      * @copydoc Blockchain::get_output_distribution
+      *
+      * @brief get per block distribution of outputs of a given amount
+      */
+     bool get_output_distribution(uint64_t amount, uint64_t from_height, uint64_t &start_height, std::vector<uint64_t> &distribution, uint64_t &base) const;
 
      /**
       * @copydoc miner::pause