1 files changed, 94 insertions, 0 deletions
diff --git a/src/wallet/wallet_rpc_helpers.h b/src/wallet/wallet_rpc_helpers.h
new file mode 100644
index 000000000..91803ff77
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+++ b/src/wallet/wallet_rpc_helpers.h
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+// Copyright (c) 2018-2019, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include <type_traits>
+
+namespace
+{
+  // credits to yrp (https://stackoverflow.com/questions/87372/check-if-a-class-has-a-member-function-of-a-given-signature
+  template <typename T>
+  struct HasCredits
+  {
+    template<typename U, uint64_t (U::*)> struct SFINAE {};
+    template<typename U> static char Test(SFINAE<U, &U::credits>*);
+    template<typename U> static int Test(...);
+    static const bool Has = sizeof(Test<T>(0)) == sizeof(char);
+  };
+}
+
+namespace tools
+{
+  struct rpc_payment_state_t
+  {
+    uint64_t credits;
+    uint64_t expected_spent;
+    uint64_t discrepancy;
+    std::string top_hash;
+    bool stale;
+
+    rpc_payment_state_t(): credits(0), expected_spent(0), discrepancy(0), stale(true) {}
+  };
+
+  static inline void check_rpc_cost(rpc_payment_state_t &rpc_payment_state, const char *call, uint64_t post_call_credits, uint64_t pre_call_credits, double expected_cost)
+  {
+    uint64_t expected_credits = (uint64_t)expected_cost;
+    if (expected_credits == 0)
+      expected_credits = 1;
+
+    rpc_payment_state.credits = post_call_credits;
+    rpc_payment_state.expected_spent += expected_credits;
+
+    if (pre_call_credits < post_call_credits)
+      return;
+
+    uint64_t cost = pre_call_credits - post_call_credits;
+
+    if (cost == expected_credits)
+    {
+      MDEBUG("Call " << call << " cost " << cost << " credits");
+      return;
+    }
+    MWARNING("Call " << call << " cost " << cost << " credits, expected " << expected_credits);
+
+    if (cost > expected_credits)
+    {
+      uint64_t d = cost - expected_credits;
+      if (rpc_payment_state.discrepancy > std::numeric_limits<uint64_t>::max() - d)
+      {
+        MERROR("Integer overflow in credit discrepancy calculation, setting to max");
+        rpc_payment_state.discrepancy = std::numeric_limits<uint64_t>::max();
+      }
+      else
+      {
+        rpc_payment_state.discrepancy += d;
+      }
+    }
+  }
+}