wallet2: do not keep block hashes below last checkpoint

This saves a lot of space and load/save time for wallet caches

tests/unit_tests/CMakeLists.txt

@@ -46,6 +46,7 @@ set(unit_tests_sources
   epee_utils.cpp
   fee.cpp
   get_xtype_from_string.cpp
+  hashchain.cpp
   http.cpp
   main.cpp
   mnemonics.cpp

tests/unit_tests/hashchain.cpp

@@ -0,0 +1,129 @@
+// Copyright (c) 2014-2017, 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.
+
+// FIXME: move this into a full wallet2 unit test suite, if possible
+
+#include "gtest/gtest.h"
+
+#include "wallet/wallet2.h"
+
+static crypto::hash make_hash(uint64_t n)
+{
+  union
+  {
+    crypto::hash hash;
+    uint64_t n;
+  } hash;
+  hash.hash = crypto::null_hash;
+  hash.n = n;
+  return hash.hash;
+}
+
+TEST(hashchain, empty)
+{
+  tools::hashchain hashchain;
+  ASSERT_EQ(hashchain.size(), 0);
+  ASSERT_EQ(hashchain.offset(), 0);
+}
+
+TEST(hashchain, genesis)
+{
+  tools::hashchain hashchain;
+  hashchain.push_back(make_hash(1));
+  ASSERT_EQ(hashchain.size(), 1);
+  ASSERT_EQ(hashchain.genesis(), make_hash(1));
+  hashchain.push_back(make_hash(2));
+  ASSERT_EQ(hashchain.size(), 2);
+  ASSERT_EQ(hashchain.genesis(), make_hash(1));
+}
+
+TEST(hashchain, push_back)
+{
+  tools::hashchain hashchain;
+  hashchain.push_back(make_hash(1));
+  hashchain.push_back(make_hash(2));
+  hashchain.push_back(make_hash(3));
+  ASSERT_EQ(hashchain[0], make_hash(1));
+  ASSERT_EQ(hashchain[1], make_hash(2));
+  ASSERT_EQ(hashchain[2], make_hash(3));
+}
+
+TEST(hashchain, clear_empty)
+{
+  tools::hashchain hashchain;
+  ASSERT_TRUE(hashchain.empty());
+  hashchain.push_back(make_hash(1));
+  ASSERT_FALSE(hashchain.empty());
+  hashchain.push_back(make_hash(2));
+  ASSERT_FALSE(hashchain.empty());
+  hashchain.clear();
+  ASSERT_TRUE(hashchain.empty());
+}
+
+TEST(hashchain, crop)
+{
+  tools::hashchain hashchain;
+  hashchain.push_back(make_hash(1));
+  hashchain.push_back(make_hash(2));
+  hashchain.push_back(make_hash(3));
+  ASSERT_EQ(hashchain.size(), 3);
+  ASSERT_EQ(hashchain[0], make_hash(1));
+  ASSERT_EQ(hashchain[1], make_hash(2));
+  ASSERT_EQ(hashchain[2], make_hash(3));
+  hashchain.crop(3);
+  ASSERT_EQ(hashchain.size(), 3);
+  hashchain.crop(2);
+  ASSERT_EQ(hashchain.size(), 2);
+  ASSERT_EQ(hashchain[0], make_hash(1));
+  ASSERT_EQ(hashchain[1], make_hash(2));
+  ASSERT_EQ(hashchain.genesis(), make_hash(1));
+  hashchain.crop(0);
+  ASSERT_TRUE(hashchain.empty());
+  ASSERT_EQ(hashchain.size(), 0);
+  hashchain.push_back(make_hash(5));
+  ASSERT_EQ(hashchain.genesis(), make_hash(5));
+  ASSERT_EQ(hashchain.size(), 1);
+}
+
+TEST(hashchain, trim)
+{
+  tools::hashchain hashchain;
+  hashchain.push_back(make_hash(1));
+  hashchain.push_back(make_hash(2));
+  hashchain.push_back(make_hash(3));
+  ASSERT_EQ(hashchain.offset(), 0);
+  hashchain.trim(2);
+  ASSERT_EQ(hashchain.offset(), 2);
+  ASSERT_EQ(hashchain.size(), 3);
+  ASSERT_EQ(hashchain[2], make_hash(3));
+  hashchain.trim(3);
+  ASSERT_EQ(hashchain.offset(), 3);
+  ASSERT_EQ(hashchain.size(), 3);
+  ASSERT_FALSE(hashchain.empty());
+  ASSERT_EQ(hashchain.genesis(), make_hash(1));
+}