blockfilter: Additional constructors for BlockFilter.

Author: jimpo

src/blockfilter.cpp

@@ -221,6 +221,17 @@ static GCSFilter::ElementSet BasicFilterElements(const CBlock& block,
     return elements;
 }
 
+BlockFilter::BlockFilter(BlockFilterType filter_type, const uint256& block_hash,
+                         std::vector<unsigned char> filter)
+    : m_filter_type(filter_type), m_block_hash(block_hash)
+{
+    GCSFilter::Params params;
+    if (!BuildParams(params)) {
+        throw std::invalid_argument("unknown filter_type");
+    }
+    m_filter = GCSFilter(params, std::move(filter));
+}
+
 BlockFilter::BlockFilter(BlockFilterType filter_type, const CBlock& block, const CBlockUndo& block_undo)
     : m_filter_type(filter_type), m_block_hash(block.GetHash())
 {

src/blockfilter.h

@@ -103,22 +103,28 @@ class BlockFilter
 
 public:
 
-    // Construct a new BlockFilter of the specified type from a block.
+    BlockFilter() = default;
+
+    //! Reconstruct a BlockFilter from parts.
+    BlockFilter(BlockFilterType filter_type, const uint256& block_hash,
+                std::vector<unsigned char> filter);
+
+    //! Construct a new BlockFilter of the specified type from a block.
     BlockFilter(BlockFilterType filter_type, const CBlock& block, const CBlockUndo& block_undo);
 
     BlockFilterType GetFilterType() const { return m_filter_type; }
-
+    const uint256& GetBlockHash() const { return m_block_hash; }
     const GCSFilter& GetFilter() const { return m_filter; }
 
     const std::vector<unsigned char>& GetEncodedFilter() const
     {
         return m_filter.GetEncoded();
     }
 
-    // Compute the filter hash.
+    //! Compute the filter hash.
     uint256 GetHash() const;
 
-    // Compute the filter header given the previous one.
+    //! Compute the filter header given the previous one.
     uint256 ComputeHeader(const uint256& prev_header) const;
 
     template <typename Stream>

src/test/blockfilter_tests.cpp

@@ -101,6 +101,17 @@ BOOST_AUTO_TEST_CASE(blockfilter_basic_test)
     for (const CScript& script : excluded_scripts) {
         BOOST_CHECK(!filter.Match(GCSFilter::Element(script.begin(), script.end())));
     }
+
+    // Test serialization/unserialization.
+    BlockFilter block_filter2;
+
+    CDataStream stream(SER_NETWORK, PROTOCOL_VERSION);
+    stream << block_filter;
+    stream >> block_filter2;
+
+    BOOST_CHECK_EQUAL(block_filter.GetFilterType(), block_filter2.GetFilterType());
+    BOOST_CHECK_EQUAL(block_filter.GetBlockHash(), block_filter2.GetBlockHash());
+    BOOST_CHECK(block_filter.GetEncodedFilter() == block_filter2.GetEncodedFilter());
 }
 
 BOOST_AUTO_TEST_CASE(blockfilters_json_test)