Add annotation (vesoft-inc#677)

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#### What type of PR is this?
- [ ] bug
- [ ] feature
- [x] enhancement

#### What problem(s) does this PR solve?
Issue(s) number: close vesoft-inc#3309 

Description:
small fix and add annotation.

#### How do you solve it?


  
#### Special notes for your reviewer, ex. impact of this fix, design document, etc:



#### Checklist:
Tests:
- [ ] Unit test(positive and negative cases)
- [ ] Function test
- [ ] Performance test
- [x] N/A

Affects:
- [ ] Documentation affected (Please add the label if documentation needs to be modified.)
- [ ] Incompatibility (If it breaks the compatibility, please describe it and add the label.）
- [ ] If it's needed to cherry-pick (If cherry-pick to some branches is required, please label the destination version(s).)
- [ ] Performance impacted: Consumes more CPU/Memory


#### Release notes:

Please confirm whether to be reflected in release notes and how to describe:
> ex. Fixed the bug .....


Migrated from vesoft-inc#4012

Co-authored-by: jakevin <30525741+jackwener@users.noreply.github.com>

src/common/expression/test/AggregateExpressionBenchmark.cpp

@@ -5,8 +5,6 @@
 
 #include <folly/Benchmark.h>
 
-#include <memory>
-
 #include "common/base/ObjectPool.h"
 #include "common/expression/AggregateExpression.h"
 #include "common/expression/ConstantExpression.h"

src/common/fs/FileUtils.cpp

@@ -92,8 +92,8 @@ StatusOr<std::string> FileUtils::readLink(const char* path) {
 }
 
 StatusOr<std::string> FileUtils::realPath(const char* path) {
- char* buffer = ::realpath(path, NULL);
- if (buffer == NULL) {
+ char* buffer = ::realpath(path, nullptr);
+ if (buffer == nullptr) {
  return Status::Error("realpath %s: %s", path, ::strerror(errno));
  }
  std::string truePath(buffer);

src/common/memory/MemoryUtils.cpp

@@ -5,13 +5,10 @@
 
 #include "common/memory/MemoryUtils.h"
 
-#include <folly/String.h>
 #include <gflags/gflags.h>
 
 #include <algorithm>
-#include <cstdio>
 #include <fstream>
-#include <regex>
 
 #include "common/fs/FileUtils.h"
 
@@ -42,7 +39,7 @@ StatusOr<bool> MemoryUtils::hitsHighWatermark() {
  uint64_t cacheSize = 0;
  for (; iter.valid(); ++iter) {
  auto& sm = iter.matched();
- cacheSize += std::stoul(sm[2].str(), NULL);
+ cacheSize += std::stoul(sm[2].str(), nullptr);
  }
 
  std::string limitPath =
@@ -64,7 +61,7 @@ StatusOr<bool> MemoryUtils::hitsHighWatermark() {
  std::vector<uint64_t> memorySize;
  for (; iter.valid(); ++iter) {
  auto& sm = iter.matched();
- memorySize.emplace_back(std::stoul(sm[2].str(), NULL) << 10);
+ memorySize.emplace_back(std::stoul(sm[2].str(), nullptr) << 10);
  }
  std::sort(memorySize.begin(), memorySize.end());
  if (memorySize.size() >= 2u) {

src/common/network/NetworkUtils.cpp

@@ -112,47 +112,47 @@ std::unordered_set<uint16_t> NetworkUtils::getPortsInUse() {
  fs::FileUtils::FileLineIterator iter("/proc/net/tcp", &regex);
  while (iter.valid()) {
  auto& sm = iter.matched();
- inUse.emplace(std::stoul(sm[1].str(), NULL, 16));
+ inUse.emplace(std::stoul(sm[1].str(), nullptr, 16));
  ++iter;
  }
  }
  {
  fs::FileUtils::FileLineIterator iter("/proc/net/tcp6", &regex);
  while (iter.valid()) {
  auto& sm = iter.matched();
- inUse.emplace(std::stoul(sm[1].str(), NULL, 16));
+ inUse.emplace(std::stoul(sm[1].str(), nullptr, 16));
  ++iter;
  }
  }
  {
  fs::FileUtils::FileLineIterator iter("/proc/net/udp", &regex);
  while (iter.valid()) {
  auto& sm = iter.matched();
- inUse.emplace(std::stoul(sm[1].str(), NULL, 16));
+ inUse.emplace(std::stoul(sm[1].str(), nullptr, 16));
  ++iter;
  }
  }
  {
  fs::FileUtils::FileLineIterator iter("/proc/net/udp6", &regex);
  while (iter.valid()) {
  auto& sm = iter.matched();
- inUse.emplace(std::stoul(sm[1].str(), NULL, 16));
+ inUse.emplace(std::stoul(sm[1].str(), nullptr, 16));
  ++iter;
  }
  }
  {
  fs::FileUtils::FileLineIterator iter("/proc/net/raw", &regex);
  while (iter.valid()) {
  auto& sm = iter.matched();
- inUse.emplace(std::stoul(sm[1].str(), NULL, 16));
+ inUse.emplace(std::stoul(sm[1].str(), nullptr, 16));
  ++iter;
  }
  }
  {
  fs::FileUtils::FileLineIterator iter("/proc/net/raw6", &regex);
  while (iter.valid()) {
  auto& sm = iter.matched();
- inUse.emplace(std::stoul(sm[1].str(), NULL, 16));
+ inUse.emplace(std::stoul(sm[1].str(), nullptr, 16));
  ++iter;
  }
  }
@@ -209,7 +209,7 @@ StatusOr<std::vector<HostAddr>> NetworkUtils::resolveHost(const std::string& hos
  continue;
  }
 
- auto address = ((struct sockaddr_in*)rp->ai_addr)->sin_addr.s_addr;
+ auto address = (reinterpret_cast<struct sockaddr_in*>(rp->ai_addr))->sin_addr.s_addr;
  // We need to match the integer byte order generated by ipv4ToInt,
  // so we need to convert here.
  addrs.emplace_back(intToIPv4(htonl(std::move(address))), port);

src/common/time/test/WallClockBenchmark.cpp

@@ -16,7 +16,7 @@ using nebula::time::WallClock;
 BENCHMARK(gettimeofday_get_msec, iters) {
  for (uint32_t i = 0; i < iters; i++) {
  struct timeval tp;
- gettimeofday(&tp, NULL);
+ gettimeofday(&tp, nullptr);
  auto ts = tp.tv_sec * 1000 + tp.tv_usec / 1000;
  folly::doNotOptimizeAway(ts);
  }
@@ -46,7 +46,7 @@ BENCHMARK_DRAW_LINE();
 BENCHMARK(gettimeofday_get_sec, iters) {
  for (uint32_t i = 0; i < iters; i++) {
  struct timeval tp;
- gettimeofday(&tp, NULL);
+ gettimeofday(&tp, nullptr);
  auto ts = tp.tv_sec;
  folly::doNotOptimizeAway(ts);
  }

src/graph/service/GraphFlags.h

@@ -45,7 +45,7 @@ DECLARE_uint32(failed_login_attempts);
 // The deault value is 0. A value of 0 disables the option.
 DECLARE_uint32(password_lock_time_in_secs);
 
-// optimizer
+// Optimizer
 DECLARE_bool(enable_optimizer);
 
 DECLARE_int64(max_allowed_connections);

src/graph/service/GraphServer.cpp

@@ -40,6 +40,7 @@ bool GraphServer::start() {
  return false;
  }
 
+ // Init worker id for snowflake generating unique id
  nebula::Snowflake::initWorkerId(interface->metaClient_.get());
 
  graphThread_ = std::make_unique<std::thread>([&] {
@@ -90,6 +91,7 @@ void GraphServer::notifyStop() {
  }
 }
 
+// Stop the server.
 void GraphServer::stop() {
  if (serverStatus_.load() == ServiceStatus::STATUS_STOPPED) {
  LOG(INFO) << "The graph server has been stopped";

src/graph/service/GraphServer.h

@@ -24,7 +24,7 @@ class GraphServer {
 
  void stop();
 
- // used for signal handler to set an internal stop flag
+ // Used for signal handler to set an internal stop flag
  void notifyStop();
 
  void waitUntilStop();

src/graph/service/GraphService.cpp

@@ -49,7 +49,7 @@ Status GraphService::init(std::shared_ptr<folly::IOThreadPoolExecutor> ioExecuto
 
  metaClient_ = std::make_unique<meta::MetaClient>(ioExecutor, std::move(addrs.value()), options);
 
- // load data try 3 time
+ // Load data try 3 time
  bool loadDataOk = metaClient_->waitForMetadReady(3);
  if (!loadDataOk) {
  // Resort to retrying in the background

src/graph/service/PermissionCheck.cpp

@@ -28,11 +28,10 @@ namespace graph {
  * Special operation : kShow, kChangePassword
  */
 
-// static
-Status PermissionCheck::permissionCheck(ClientSession *session,
- Sentence *sentence,
- ValidateContext *vctx,
- GraphSpaceID targetSpace) {
+/* static */ Status PermissionCheck::permissionCheck(ClientSession *session,
+ Sentence *sentence,
+ ValidateContext *vctx,
+ GraphSpaceID targetSpace) {
  if (!FLAGS_enable_authorize) {
  return Status::OK();
  }
@@ -177,7 +176,7 @@ Status PermissionCheck::permissionCheck(ClientSession *session,
  case Sentence::Kind::kShowMetaLeader:
  case Sentence::Kind::kShowHosts: {
  /**
- * all roles can be show for above operations.
+ * All roles can be show for above operations.
  */
  return Status::OK();
  }
@@ -218,7 +217,7 @@ Status PermissionCheck::permissionCheck(ClientSession *session,
  return Status::OK();
  }
  case Sentence::Kind::kExplain:
- // everyone could explain
+ // Everyone could explain
  return Status::OK();
  case Sentence::Kind::kSequential: {
  // No permission checking for sequential sentence.

src/graph/service/PermissionManager.cpp

@@ -10,8 +10,7 @@
 namespace nebula {
 namespace graph {
 
-// static
-Status PermissionManager::canReadSpace(ClientSession *session, GraphSpaceID spaceId) {
+/* static */ Status PermissionManager::canReadSpace(ClientSession *session, GraphSpaceID spaceId) {
  if (!FLAGS_enable_authorize) {
  return Status::OK();
  }
@@ -35,8 +34,8 @@ Status PermissionManager::canReadSpace(ClientSession *session, GraphSpaceID spac
  return Status::PermissionError("No permission to read space.");
 }
 
-// static
-Status PermissionManager::canReadSchemaOrData(ClientSession *session, ValidateContext *vctx) {
+/* static */ Status PermissionManager::canReadSchemaOrData(ClientSession *session,
+  ValidateContext *vctx) {
  if (!FLAGS_enable_authorize) {
  return Status::OK();
  }
@@ -60,8 +59,7 @@ Status PermissionManager::canReadSchemaOrData(ClientSession *session, ValidateCo
  return Status::PermissionError("No permission to read schema/data.");
 }
 
-// static
-Status PermissionManager::canWriteSpace(ClientSession *session) {
+/* static */ Status PermissionManager::canWriteSpace(ClientSession *session) {
  if (!FLAGS_enable_authorize) {
  return Status::OK();
  }
@@ -71,8 +69,8 @@ Status PermissionManager::canWriteSpace(ClientSession *session) {
  return Status::PermissionError("No permission to write space.");
 }
 
-// static
-Status PermissionManager::canWriteSchema(ClientSession *session, ValidateContext *vctx) {
+/* static */ Status PermissionManager::canWriteSchema(ClientSession *session,
+  ValidateContext *vctx) {
  if (!FLAGS_enable_authorize) {
  return Status::OK();
  }
@@ -100,8 +98,7 @@ Status PermissionManager::canWriteSchema(ClientSession *session, ValidateContext
  return Status::PermissionError("No permission to write schema.");
 }
 
-// static
-Status PermissionManager::canWriteUser(ClientSession *session) {
+/* static */ Status PermissionManager::canWriteUser(ClientSession *session) {
  if (!FLAGS_enable_authorize) {
  return Status::OK();
  }
@@ -116,8 +113,8 @@ Status PermissionManager::canWriteUser(ClientSession *session) {
  }
 }
 
-// static
-Status PermissionManager::canReadUser(ClientSession *session, const std::string &targetUser) {
+/* static */ Status PermissionManager::canReadUser(ClientSession *session,
+  const std::string &targetUser) {
  if (!FLAGS_enable_authorize) {
  return Status::OK();
  }
@@ -180,10 +177,9 @@ Status PermissionManager::canWriteRole(ClientSession *session,
  targetUser.c_str());
 }
 
-// static
-Status PermissionManager::canWriteData(ClientSession *session,
- ValidateContext *vctx,
- bool isAdminJob) {
+/* static */ Status PermissionManager::canWriteData(ClientSession *session,
+ ValidateContext *vctx,
+ bool isAdminJob) {
  if (!FLAGS_enable_authorize) {
  return Status::OK();
  }

src/graph/service/PermissionManager.h

@@ -16,6 +16,7 @@
 namespace nebula {
 namespace graph {
 
+// This module is responsible for checking the permission of the user
 class PermissionManager final {
  public:
  PermissionManager() = delete;

src/graph/service/QueryEngine.cpp

@@ -34,6 +34,7 @@ Status QueryEngine::init(std::shared_ptr<folly::IOThreadPoolExecutor> ioExecutor
 
  PlannersRegister::registerPlanners();
 
+ // Set default optimizer rules
  std::vector<const opt::RuleSet*> rulesets{&opt::RuleSet::DefaultRules()};
  if (FLAGS_enable_optimizer) {
  rulesets.emplace_back(&opt::RuleSet::QueryRules());
@@ -43,6 +44,7 @@ Status QueryEngine::init(std::shared_ptr<folly::IOThreadPoolExecutor> ioExecutor
  return setupMemoryMonitorThread();
 }
 
+// Create query context and query instance and execute it
 void QueryEngine::execute(RequestContextPtr rctx) {
  auto qctx = std::make_unique<QueryContext>(std::move(rctx),
  schemaManager_.get(),

src/graph/service/QueryInstance.cpp

@@ -44,11 +44,14 @@ void QueryInstance::execute() {
  return;
  }
 
+ // Sentence is explain query, finish
  if (!explainOrContinue()) {
  onFinish();
  return;
  }
 
+ // The execution engine converts the physical execution plan generated by the Planner into a
+ // series of Executors through the Scheduler to drive the execution of the Executors.
  scheduler_->schedule()
  .thenValue([this](Status s) {
  if (s.ok()) {
@@ -67,6 +70,7 @@ Status QueryInstance::validateAndOptimize() {
  auto *rctx = qctx()->rctx();
  auto &spaceName = rctx->session()->space().name;
  VLOG(1) << "Parsing query: " << rctx->query();
+ // Result of parsing, get the parsing tree
  auto result = GQLParser(qctx()).parse(rctx->query());
  NG_RETURN_IF_ERROR(result);
  sentence_ = std::move(result).value();
@@ -85,7 +89,9 @@ Status QueryInstance::validateAndOptimize() {
  }
  }
 
+ // Validate the query, if failed, return
  NG_RETURN_IF_ERROR(Validator::validate(sentence_.get(), qctx()));
+ // Optimize the query, and get the execution plan
  NG_RETURN_IF_ERROR(findBestPlan());
  stats::StatsManager::addValue(kOptimizerLatencyUs, *(qctx_->plan()->optimizeTimeInUs()));
  if (FLAGS_enable_space_level_metrics && spaceName != "") {
@@ -214,6 +220,7 @@ void QueryInstance::addSlowQueryStats(uint64_t latency, const std::string &space
  }
 }
 
+// Get result from query context and fill the response
 void QueryInstance::fillRespData(ExecutionResponse *resp) {
  auto ectx = DCHECK_NOTNULL(qctx_->ectx());
  auto plan = DCHECK_NOTNULL(qctx_->plan());
@@ -223,7 +230,7 @@ void QueryInstance::fillRespData(ExecutionResponse *resp) {
  auto &&value = ectx->moveValue(name);
  if (!value.isDataSet()) return;
 
- // fill dataset
+ // Fill dataset
  auto result = value.moveDataSet();
  if (!result.colNames.empty()) {
  resp->data = std::make_unique<DataSet>(std::move(result));
@@ -234,6 +241,7 @@ void QueryInstance::fillRespData(ExecutionResponse *resp) {
  }
 }
 
+// The entry point of the optimizer
 Status QueryInstance::findBestPlan() {
  auto plan = qctx_->plan();
  SCOPED_TIMER(plan->optimizeTimeInUs());

src/graph/service/QueryInstance.h

@@ -29,6 +29,7 @@ class QueryInstance final : public boost::noncopyable, public cpp::NonMovable {
  QueryInstance(std::unique_ptr<QueryContext> qctx, opt::Optimizer* optimizer);
  ~QueryInstance() = default;
 
+ // Entrance of the Validate, Optimize, Schedule, Execute process
  void execute();
 
  QueryContext* qctx() const {
@@ -51,7 +52,7 @@ class QueryInstance final : public boost::noncopyable, public cpp::NonMovable {
  void onError(Status);
 
  Status validateAndOptimize();
- // return true if continue to execute
+ // Return true if continue to execute
  bool explainOrContinue();
  void addSlowQueryStats(uint64_t latency, const std::string& spaceName) const;
  void fillRespData(ExecutionResponse* resp);