leveldb: Add DBTracker for exposing databases to Chrome's memory-infra.

third_party/leveldatabase/env_chromium_unittest.cc

Index: third_party/leveldatabase/env_chromium_unittest.cc
diff --git a/third_party/leveldatabase/env_chromium_unittest.cc b/third_party/leveldatabase/env_chromium_unittest.cc
index 57bca249af8cdefad5c720aa7b16703dfc18bacc..78cc87013d9457d350546a38b154bd4e92f8812b 100644
--- a/third_party/leveldatabase/env_chromium_unittest.cc
+++ b/third_party/leveldatabase/env_chromium_unittest.cc
@@ -2,15 +2,16 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "third_party/leveldatabase/env_chromium.h"
 #include "base/files/file.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/lazy_instance.h"
+#include "base/macros.h"
 #include "base/test/test_suite.h"
 #include "testing/gtest/include/gtest/gtest.h"
-#include "third_party/leveldatabase/env_chromium.h"
 #include "third_party/leveldatabase/src/include/leveldb/db.h"
 
 #define FPL FILE_PATH_LITERAL
@@ -190,4 +191,98 @@ TEST(ChromiumEnv, TestWriteBufferSize) {
   EXPECT_EQ(size_t(4 * MB), leveldb_env::WriteBufferSize(100 * MB * MB));
 }
 
+TEST(ChromiumEnv, DBRegistryOpen) {
+  base::ScopedTempDir scoped_temp_dir;
+  ASSERT_TRUE(scoped_temp_dir.CreateUniqueTempDir());
+  base::FilePath dir = scoped_temp_dir.GetPath();
+
+  struct KeyValue {
+    const char* key;
+    const char* value;
+  };
+  constexpr KeyValue db_data[] = {
+      {"banana", "yellow"}, {"sky", "blue"}, {"enthusiasm", ""},
+  };
+
+  // Open a new database using DBRegistry::Open, write some data
+  Options options;
+  options.create_if_missing = true;
+  DB* db;
+  Status status =
+      leveldb_env::DBRegistry::Open(options, dir.AsUTF8Unsafe(), &db);
+  ASSERT_TRUE(status.ok()) << status.ToString();
+  for (const auto& kv : db_data) {
+    status = db->Put(WriteOptions(), kv.key, kv.value);
+    ASSERT_TRUE(status.ok()) << status.ToString();
+  }
+
+  // Close the database
+  delete db;
+
+  // Open the database again with DB::Open, and check the data
+  options.create_if_missing = false;
+  status = leveldb::DB::Open(options, dir.AsUTF8Unsafe(), &db);
+  ASSERT_TRUE(status.ok()) << status.ToString();
+  for (const auto& kv : db_data) {
+    std::string value;
+    status = db->Get(ReadOptions(), kv.key, &value);
+    ASSERT_TRUE(status.ok()) << status.ToString();
+    ASSERT_EQ(value, kv.value);
+  }
+  delete db;
+}
+
+TEST(ChromiumEnv, DBRegistryVisitDatabases) {
+  base::ScopedTempDir scoped_temp_dir;
+  ASSERT_TRUE(scoped_temp_dir.CreateUniqueTempDir());
+
+  struct NamedDB {
+    const char* tag;
+    std::string name;
+    std::unique_ptr<DB> db;
+  };
+  NamedDB named_dbs[] = {
+      {"poets"}, {"movies"}, {"recipes"}, {"misconceptions"},
+  };
+
+  // Open databases
+  for (auto& named_db : named_dbs) {
+    Options options;
+    options.create_if_missing = true;
+    std::string name =
+        scoped_temp_dir.GetPath().Append(named_db.tag).AsUTF8Unsafe();
+    DB* db;
+    Status status = leveldb_env::DBRegistry::Open(options, name, &db);
+    ASSERT_TRUE(status.ok()) << status.ToString();
+    named_db.name = name;
+    named_db.db.reset(db);
+  }
+
+  size_t visited_db_count;
+  auto db_visitor = [&](leveldb_env::DBRegistry::DBWrapper* db) {
+    for (const auto& named_db : named_dbs) {
+      if (db->name() == named_db.name) {
+        ASSERT_EQ(named_db.db.get(), db);
+        visited_db_count += 1;
+        return;
+      }
+    }
+    ASSERT_TRUE(false) << "Visited unknown database '" << db->name() << "'";
+  };
+
+  // Check that VisitDatabases() visits all opened databases
+  visited_db_count = 0;
+  leveldb_env::DBRegistry::GetInstance()->VisitDatabases(db_visitor);
+  ASSERT_EQ(visited_db_count, arraysize(named_dbs));
+
+  // Close couple databases
+  named_dbs[0].db.reset();
+  named_dbs[2].db.reset();
+
+  // Check that VisitDatabases() visits only the remaining ones
+  visited_db_count = 0;
+  leveldb_env::DBRegistry::GetInstance()->VisitDatabases(db_visitor);
+  ASSERT_EQ(visited_db_count, arraysize(named_dbs) - 2);
+}
+
 int main(int argc, char** argv) { return base::TestSuite(argc, argv).Run(); }