1 files changed, 100 insertions, 0 deletions
diff --git a/src/rocksdb/java/rocksjni/memory_util.cc b/src/rocksdb/java/rocksjni/memory_util.cc
new file mode 100644
index 00000000..04385021
--- /dev/null
+++ b/src/rocksdb/java/rocksjni/memory_util.cc
@@ -0,0 +1,100 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include <jni.h>
+#include <map>
+#include <string>
+#include <unordered_set>
+#include <vector>
+
+#include "include/org_rocksdb_MemoryUtil.h"
+
+#include "rocksjni/portal.h"
+
+#include "rocksdb/utilities/memory_util.h"
+
+
+/*
+ * Class:     org_rocksdb_MemoryUtil
+ * Method:    getApproximateMemoryUsageByType
+ * Signature: ([J[J)Ljava/util/Map;
+ */
+jobject Java_org_rocksdb_MemoryUtil_getApproximateMemoryUsageByType(
+    JNIEnv *env, jclass /*jclazz*/, jlongArray jdb_handles, jlongArray jcache_handles) {
+
+  std::vector<rocksdb::DB*> dbs;
+  jsize db_handle_count = env->GetArrayLength(jdb_handles);
+  if(db_handle_count > 0) {
+    jlong *ptr_jdb_handles = env->GetLongArrayElements(jdb_handles, nullptr);
+    if (ptr_jdb_handles == nullptr) {
+      // exception thrown: OutOfMemoryError
+      return nullptr;
+    }
+    for (jsize i = 0; i < db_handle_count; i++) {
+      dbs.push_back(reinterpret_cast<rocksdb::DB *>(ptr_jdb_handles[i]));
+    }
+    env->ReleaseLongArrayElements(jdb_handles, ptr_jdb_handles, JNI_ABORT);
+  }
+
+  std::unordered_set<const rocksdb::Cache*> cache_set;
+  jsize cache_handle_count = env->GetArrayLength(jcache_handles);
+  if(cache_handle_count > 0) {
+    jlong *ptr_jcache_handles = env->GetLongArrayElements(jcache_handles, nullptr);
+    if (ptr_jcache_handles == nullptr) {
+      // exception thrown: OutOfMemoryError
+      return nullptr;
+    }
+    for (jsize i = 0; i < cache_handle_count; i++) {
+      auto *cache_ptr =
+          reinterpret_cast<std::shared_ptr<rocksdb::Cache> *>(ptr_jcache_handles[i]);
+      cache_set.insert(cache_ptr->get());
+    }
+    env->ReleaseLongArrayElements(jcache_handles, ptr_jcache_handles, JNI_ABORT);
+  }
+
+  std::map<rocksdb::MemoryUtil::UsageType, uint64_t> usage_by_type;
+  if(rocksdb::MemoryUtil::GetApproximateMemoryUsageByType(dbs, cache_set, &usage_by_type) != rocksdb::Status::OK()) {
+    // Non-OK status
+    return nullptr;
+  }
+
+  jobject jusage_by_type = rocksdb::HashMapJni::construct(
+      env, static_cast<uint32_t>(usage_by_type.size()));
+  if (jusage_by_type == nullptr) {
+    // exception occurred
+    return nullptr;
+  }
+  const rocksdb::HashMapJni::FnMapKV<const rocksdb::MemoryUtil::UsageType, const uint64_t, jobject, jobject>
+      fn_map_kv =
+      [env](const std::pair<rocksdb::MemoryUtil::UsageType, uint64_t>& pair) {
+        // Construct key
+        const jobject jusage_type =
+            rocksdb::ByteJni::valueOf(env, rocksdb::MemoryUsageTypeJni::toJavaMemoryUsageType(pair.first));
+        if (jusage_type == nullptr) {
+          // an error occurred
+          return std::unique_ptr<std::pair<jobject, jobject>>(nullptr);
+        }
+        // Construct value
+        const jobject jusage_value =
+            rocksdb::LongJni::valueOf(env, pair.second);
+        if (jusage_value == nullptr) {
+          // an error occurred
+          return std::unique_ptr<std::pair<jobject, jobject>>(nullptr);
+        }
+        // Construct and return pointer to pair of jobjects
+        return std::unique_ptr<std::pair<jobject, jobject>>(
+            new std::pair<jobject, jobject>(jusage_type,
+                                            jusage_value));
+      };
+
+  if (!rocksdb::HashMapJni::putAll(env, jusage_by_type, usage_by_type.begin(),
+                                   usage_by_type.end(), fn_map_kv)) {
+    // exception occcurred
+    jusage_by_type = nullptr;
+  }
+
+  return jusage_by_type;
+
+}