From bb485e986a1ca782cfd87b9f6c0f800346c85a30 Mon Sep 17 00:00:00 2001
From: qieqieplus <admin@qieqie.me>
Date: Fri, 9 Jul 2021 15:44:57 -0700
Subject: [PATCH] Add ribbon filter to C API (#8486)

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8486

Reviewed By: jay-zhuang

Differential Revision: D29625501

Pulled By: pdillinger

fbshipit-source-id: e6e2a455ae62a71f3a202278a751b9bba17ad03c
---
 db/c.cc             | 42 ++++++++++++++++++++++++++++++++++++++++++
 db/c_test.c         | 11 ++++++++---
 include/rocksdb/c.h |  2 ++
 3 files changed, 52 insertions(+), 3 deletions(-)

diff --git a/db/c.cc b/db/c.cc
index 3c719e6ff..4e9c6ec22 100644
--- a/db/c.cc
+++ b/db/c.cc
@@ -88,6 +88,7 @@ using ROCKSDB_NAMESPACE::NewBloomFilterPolicy;
 using ROCKSDB_NAMESPACE::NewCompactOnDeletionCollectorFactory;
 using ROCKSDB_NAMESPACE::NewGenericRateLimiter;
 using ROCKSDB_NAMESPACE::NewLRUCache;
+using ROCKSDB_NAMESPACE::NewRibbonFilterPolicy;
 using ROCKSDB_NAMESPACE::OptimisticTransactionDB;
 using ROCKSDB_NAMESPACE::OptimisticTransactionOptions;
 using ROCKSDB_NAMESPACE::Options;
@@ -3882,6 +3883,47 @@ rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_bloom(int bits_per_key) {
   return rocksdb_filterpolicy_create_bloom_format(bits_per_key, true);
 }
 
+rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_ribbon_format(
+    int bloom_equivalent_bits_per_key) {
+  // Make a rocksdb_filterpolicy_t, but override all of its methods so
+  // they delegate to a NewRibbonFilterPolicy() instead of user
+  // supplied C functions.
+  struct Wrapper : public rocksdb_filterpolicy_t {
+    const FilterPolicy* rep_;
+    ~Wrapper() override { delete rep_; }
+    const char* Name() const override { return rep_->Name(); }
+    void CreateFilter(const Slice* keys, int n,
+                      std::string* dst) const override {
+      return rep_->CreateFilter(keys, n, dst);
+    }
+    bool KeyMayMatch(const Slice& key, const Slice& filter) const override {
+      return rep_->KeyMayMatch(key, filter);
+    }
+    ROCKSDB_NAMESPACE::FilterBitsBuilder* GetBuilderWithContext(
+        const ROCKSDB_NAMESPACE::FilterBuildingContext& context)
+        const override {
+      return rep_->GetBuilderWithContext(context);
+    }
+    ROCKSDB_NAMESPACE::FilterBitsReader* GetFilterBitsReader(
+        const Slice& contents) const override {
+      return rep_->GetFilterBitsReader(contents);
+    }
+    static void DoNothing(void*) {}
+  };
+  Wrapper* wrapper = new Wrapper;
+  wrapper->rep_ = NewRibbonFilterPolicy(bloom_equivalent_bits_per_key);
+  wrapper->state_ = nullptr;
+  wrapper->delete_filter_ = nullptr;
+  wrapper->destructor_ = &Wrapper::DoNothing;
+  return wrapper;
+}
+
+rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_ribbon(
+    int bloom_equivalent_bits_per_key) {
+  return rocksdb_filterpolicy_create_ribbon_format(
+      bloom_equivalent_bits_per_key);
+}
+
 rocksdb_mergeoperator_t* rocksdb_mergeoperator_create(
     void* state, void (*destructor)(void*),
     char* (*full_merge)(void*, const char* key, size_t key_length,
diff --git a/db/c_test.c b/db/c_test.c
index 5b7459b06..eb94eb864 100644
--- a/db/c_test.c
+++ b/db/c_test.c
@@ -1043,7 +1043,7 @@ int main(int argc, char** argv) {
   }
 
   StartPhase("filter");
-  for (run = 0; run <= 2; run++) {
+  for (run = 0; run <= 3; run++) {
     // First run uses custom filter
     // Second run uses old block-based bloom filter
     // Third run uses full bloom filter
@@ -1054,8 +1054,10 @@ int main(int argc, char** argv) {
                                            FilterKeyMatch, NULL, FilterName);
     } else if (run == 1) {
       policy = rocksdb_filterpolicy_create_bloom(8);
-    } else {
+    } else if (run == 2) {
       policy = rocksdb_filterpolicy_create_bloom_full(8);
+    } else {
+      policy = rocksdb_filterpolicy_create_ribbon(8);
     }
     rocksdb_block_based_options_set_filter_policy(table_options, policy);
 
@@ -1121,9 +1123,12 @@ int main(int argc, char** argv) {
       } else if (run == 1) {
         // Essentially a fingerprint of the block-based Bloom schema
         CheckCondition(hits == 241);
-      } else {
+      } else if (run == 2) {
         // Essentially a fingerprint of full Bloom schema, format_version=5
         CheckCondition(hits == 188);
+      } else {
+        // Essentially a fingerprint of Ribbon schema
+        CheckCondition(hits == 226);
       }
       CheckCondition(
           (keys_to_query - hits) ==
diff --git a/include/rocksdb/c.h b/include/rocksdb/c.h
index 8280b25a2..51fe928e8 100644
--- a/include/rocksdb/c.h
+++ b/include/rocksdb/c.h
@@ -1602,6 +1602,8 @@ extern ROCKSDB_LIBRARY_API rocksdb_filterpolicy_t*
 rocksdb_filterpolicy_create_bloom(int bits_per_key);
 extern ROCKSDB_LIBRARY_API rocksdb_filterpolicy_t*
 rocksdb_filterpolicy_create_bloom_full(int bits_per_key);
+extern ROCKSDB_LIBRARY_API rocksdb_filterpolicy_t*
+rocksdb_filterpolicy_create_ribbon(int bloom_equivalent_bits_per_key);
 
 /* Merge Operator */