From accc8b8b1842ed6d522b71a056777bcac8f39e81 Mon Sep 17 00:00:00 2001
From: Jim Posen <jim.posen@gmail.com>
Date: Thu, 30 Aug 2018 08:30:23 -0700
Subject: [PATCH] index: Access functions for global block filter indexes.

---
 src/index/blockfilterindex.cpp       | 33 +++++++++++++++++++++++
 src/index/blockfilterindex.h         | 26 +++++++++++++++++++
 src/test/blockfilter_index_tests.cpp | 39 ++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+)

diff --git a/src/index/blockfilterindex.cpp b/src/index/blockfilterindex.cpp
index a55aeca704..20f33baf2c 100644
--- a/src/index/blockfilterindex.cpp
+++ b/src/index/blockfilterindex.cpp
@@ -94,6 +94,8 @@ struct DBHashKey {
 
 }; // namespace
 
+static std::map<BlockFilterType, BlockFilterIndex> g_filter_indexes;
+
 BlockFilterIndex::BlockFilterIndex(BlockFilterType filter_type,
                                    size_t n_cache_size, bool f_memory, bool f_wipe)
     : m_filter_type(filter_type)
@@ -432,3 +434,34 @@ bool BlockFilterIndex::LookupFilterHashRange(int start_height, const CBlockIndex
     }
     return true;
 }
+
+BlockFilterIndex* GetBlockFilterIndex(BlockFilterType filter_type)
+{
+    auto it = g_filter_indexes.find(filter_type);
+    return it != g_filter_indexes.end() ? &it->second : nullptr;
+}
+
+void ForEachBlockFilterIndex(std::function<void (BlockFilterIndex&)> fn)
+{
+    for (auto& entry : g_filter_indexes) fn(entry.second);
+}
+
+bool InitBlockFilterIndex(BlockFilterType filter_type,
+                          size_t n_cache_size, bool f_memory, bool f_wipe)
+{
+    auto result = g_filter_indexes.emplace(std::piecewise_construct,
+                                           std::forward_as_tuple(filter_type),
+                                           std::forward_as_tuple(filter_type,
+                                                                 n_cache_size, f_memory, f_wipe));
+    return result.second;
+}
+
+bool DestroyBlockFilterIndex(BlockFilterType filter_type)
+{
+    return g_filter_indexes.erase(filter_type);
+}
+
+void DestroyAllBlockFilterIndexes()
+{
+    g_filter_indexes.clear();
+}
diff --git a/src/index/blockfilterindex.h b/src/index/blockfilterindex.h
index a689461800..436d52515f 100644
--- a/src/index/blockfilterindex.h
+++ b/src/index/blockfilterindex.h
@@ -65,4 +65,30 @@ public:
                                std::vector<uint256>& hashes_out) const;
 };
 
+/**
+ * Get a block filter index by type. Returns nullptr if index has not been initialized or was
+ * already destroyed.
+ */
+BlockFilterIndex* GetBlockFilterIndex(BlockFilterType filter_type);
+
+/** Iterate over all running block filter indexes, invoking fn on each. */
+void ForEachBlockFilterIndex(std::function<void (BlockFilterIndex&)> fn);
+
+/**
+ * Initialize a block filter index for the given type if one does not already exist. Returns true if
+ * a new index is created and false if one has already been initialized.
+ */
+bool InitBlockFilterIndex(BlockFilterType filter_type,
+                          size_t n_cache_size, bool f_memory = false, bool f_wipe = false);
+
+/**
+ * Destroy the block filter index with the given type. Returns false if no such index exists. This
+ * just releases the allocated memory and closes the database connection, it does not delete the
+ * index data.
+ */
+bool DestroyBlockFilterIndex(BlockFilterType filter_type);
+
+/** Destroy all open block filter indexes. */
+void DestroyAllBlockFilterIndexes();
+
 #endif // BITCOIN_INDEX_BLOCKFILTERINDEX_H
diff --git a/src/test/blockfilter_index_tests.cpp b/src/test/blockfilter_index_tests.cpp
index 5893030971..f0a24777a6 100644
--- a/src/test/blockfilter_index_tests.cpp
+++ b/src/test/blockfilter_index_tests.cpp
@@ -265,4 +265,43 @@ BOOST_FIXTURE_TEST_CASE(blockfilter_index_initial_sync, TestChain100Setup)
     filter_index.Stop();
 }
 
+BOOST_FIXTURE_TEST_CASE(blockfilter_index_init_destroy, BasicTestingSetup)
+{
+    SetDataDir("tempdir");
+
+    BlockFilterIndex* filter_index;
+
+    filter_index = GetBlockFilterIndex(BlockFilterType::BASIC);
+    BOOST_CHECK(filter_index == nullptr);
+
+    BOOST_CHECK(InitBlockFilterIndex(BlockFilterType::BASIC, 1 << 20, true, false));
+
+    filter_index = GetBlockFilterIndex(BlockFilterType::BASIC);
+    BOOST_CHECK(filter_index != nullptr);
+    BOOST_CHECK(filter_index->GetFilterType() == BlockFilterType::BASIC);
+
+    // Initialize returns false if index already exists.
+    BOOST_CHECK(!InitBlockFilterIndex(BlockFilterType::BASIC, 1 << 20, true, false));
+
+    int iter_count = 0;
+    ForEachBlockFilterIndex([&iter_count](BlockFilterIndex& _index) { iter_count++; });
+    BOOST_CHECK_EQUAL(iter_count, 1);
+
+    BOOST_CHECK(DestroyBlockFilterIndex(BlockFilterType::BASIC));
+
+    // Destroy returns false because index was already destroyed.
+    BOOST_CHECK(!DestroyBlockFilterIndex(BlockFilterType::BASIC));
+
+    filter_index = GetBlockFilterIndex(BlockFilterType::BASIC);
+    BOOST_CHECK(filter_index == nullptr);
+
+    // Reinitialize index.
+    BOOST_CHECK(InitBlockFilterIndex(BlockFilterType::BASIC, 1 << 20, true, false));
+
+    DestroyAllBlockFilterIndexes();
+
+    filter_index = GetBlockFilterIndex(BlockFilterType::BASIC);
+    BOOST_CHECK(filter_index == nullptr);
+}
+
 BOOST_AUTO_TEST_SUITE_END()