#ifndef SRC_NODE_SQLITE_H_
#define SRC_NODE_SQLITE_H_

#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#include "base_object.h"
#include "lru_cache-inl.h"
#include "node_mem.h"
#include "sqlite3.h"
#include "util.h"

#include <algorithm>
#include <array>
#include <list>
#include <map>
#include <optional>
#include <string_view>
#include <unordered_set>
#include <vector>

namespace node {

namespace diagnostics_channel {
class Channel;
}  // namespace diagnostics_channel

class ExternalReferenceRegistry;

namespace sqlite {

// Mapping from JavaScript property names to SQLite limit constants
struct LimitInfo {
  std::string_view js_name;
  int sqlite_limit_id;
};

inline constexpr std::array<LimitInfo, 11> kLimitMapping = {{
    {"length", SQLITE_LIMIT_LENGTH},
    {"sqlLength", SQLITE_LIMIT_SQL_LENGTH},
    {"column", SQLITE_LIMIT_COLUMN},
    {"exprDepth", SQLITE_LIMIT_EXPR_DEPTH},
    {"compoundSelect", SQLITE_LIMIT_COMPOUND_SELECT},
    {"vdbeOp", SQLITE_LIMIT_VDBE_OP},
    {"functionArg", SQLITE_LIMIT_FUNCTION_ARG},
    {"attach", SQLITE_LIMIT_ATTACHED},
    {"likePatternLength", SQLITE_LIMIT_LIKE_PATTERN_LENGTH},
    {"variableNumber", SQLITE_LIMIT_VARIABLE_NUMBER},
    {"triggerDepth", SQLITE_LIMIT_TRIGGER_DEPTH},
}};

constexpr bool CheckLimitIndices() {
  for (size_t i = 0; i < kLimitMapping.size(); ++i) {
    if (kLimitMapping[i].sqlite_limit_id != static_cast<int>(i)) {
      return false;
    }
  }
  return true;
}
static_assert(
    CheckLimitIndices(),
    "Each kLimitMapping entry's sqlite_limit_id must match its index");

// Mapping from JavaScript counter names to SQLite statement status constants
struct StatusInfo {
  std::string_view js_name;
  int sqlite_status_id;
};

// SQLITE_STMTSTATUS_FILTER_HIT and SQLITE_STMTSTATUS_FILTER_MISS require
// SQLite >= 3.38.0. Older shared-library builds omit the two counters.
#if SQLITE_VERSION_NUMBER >= 3038000
#define NODE_SQLITE_HAS_FILTER_STATUS 1
#endif

inline constexpr auto kStatusMapping = std::to_array<StatusInfo>({
    {"fullscanStep", SQLITE_STMTSTATUS_FULLSCAN_STEP},
    {"sort", SQLITE_STMTSTATUS_SORT},
    {"autoindex", SQLITE_STMTSTATUS_AUTOINDEX},
    {"vmStep", SQLITE_STMTSTATUS_VM_STEP},
    {"reprepare", SQLITE_STMTSTATUS_REPREPARE},
    {"run", SQLITE_STMTSTATUS_RUN},
#ifdef NODE_SQLITE_HAS_FILTER_STATUS
    {"filterMiss", SQLITE_STMTSTATUS_FILTER_MISS},
    {"filterHit", SQLITE_STMTSTATUS_FILTER_HIT},
#endif
    {"memused", SQLITE_STMTSTATUS_MEMUSED},
});

class DatabaseOpenConfiguration {
 public:
  explicit DatabaseOpenConfiguration(std::string&& location)
      : location_(std::move(location)) {}

  inline const std::string& location() const { return location_; }

  inline bool get_read_only() const { return read_only_; }

  inline void set_read_only(bool flag) { read_only_ = flag; }

  inline bool get_enable_foreign_keys() const { return enable_foreign_keys_; }

  inline void set_enable_foreign_keys(bool flag) {
    enable_foreign_keys_ = flag;
  }

  inline bool get_enable_dqs() const { return enable_dqs_; }

  inline void set_enable_dqs(bool flag) { enable_dqs_ = flag; }

  inline void set_timeout(int timeout) { timeout_ = timeout; }

  inline int get_timeout() { return timeout_; }

  inline void set_use_big_ints(bool flag) { use_big_ints_ = flag; }

  inline bool get_use_big_ints() const { return use_big_ints_; }

  inline void set_return_arrays(bool flag) { return_arrays_ = flag; }

  inline bool get_return_arrays() const { return return_arrays_; }

  inline void set_allow_bare_named_params(bool flag) {
    allow_bare_named_params_ = flag;
  }

  inline bool get_allow_bare_named_params() const {
    return allow_bare_named_params_;
  }

  inline void set_allow_unknown_named_params(bool flag) {
    allow_unknown_named_params_ = flag;
  }

  inline bool get_allow_unknown_named_params() const {
    return allow_unknown_named_params_;
  }

  inline void set_enable_defensive(bool flag) { defensive_ = flag; }

  inline bool get_enable_defensive() const { return defensive_; }

  inline void set_limit(int sqlite_limit_id, int value) {
    limits_.at(sqlite_limit_id) = value;
  }

  inline const std::array<std::optional<int>, kLimitMapping.size()>& limits()
      const {
    return limits_;
  }

 private:
  std::string location_;
  bool read_only_ = false;
  bool enable_foreign_keys_ = true;
  bool enable_dqs_ = false;
  int timeout_ = 0;
  bool use_big_ints_ = false;
  bool return_arrays_ = false;
  bool allow_bare_named_params_ = true;
  bool allow_unknown_named_params_ = false;
  bool defensive_ = true;
  std::array<std::optional<int>, kLimitMapping.size()> limits_{};
};

class Database;
class DatabaseLimits;
class StatementIterator;
class Statement;
class BackupJob;
class Session;

inline void FinalizeStatement(sqlite3_stmt* stmt) {
  sqlite3_finalize(stmt);
}

inline void CloseConnection(sqlite3* db) {
  sqlite3_close_v2(db);
}

inline void FinishBackup(sqlite3_backup* backup) {
  sqlite3_backup_finish(backup);
}

using StatementPtr = DeleteFnPtr<sqlite3_stmt, FinalizeStatement>;
using ConnectionPtr = DeleteFnPtr<sqlite3, CloseConnection>;
using BackupPtr = DeleteFnPtr<sqlite3_backup, FinishBackup>;
using SessionPtr = DeleteFnPtr<sqlite3_session, sqlite3session_delete>;

class StatementExecutionHelper {
 public:
  static v8::MaybeLocal<v8::Value> All(Environment* env, Statement* statement);
  static v8::MaybeLocal<v8::Object> Run(Environment* env, Statement* statement);
  static BaseObjectPtr<StatementIterator> Iterate(
      Environment* env, BaseObjectPtr<Statement> stmt);
  static v8::MaybeLocal<v8::Value> ColumnToValue(Environment* env,
                                                 sqlite3_stmt* stmt,
                                                 const int column,
                                                 bool use_big_ints);
  static v8::MaybeLocal<v8::Value> Get(Environment* env, Statement* statement);
};

class Database;

class BindingData : public BaseObject {
 public:
  SET_BINDING_ID(sqlite_binding_data)

  BindingData(Realm* realm, v8::Local<v8::Object> wrap);

  void MemoryInfo(MemoryTracker* tracker) const override;
  SET_MEMORY_INFO_NAME(BindingData)
  SET_SELF_SIZE(BindingData)

  std::unordered_set<Database*> open_databases;

  static void CreatePerContextProperties(v8::Local<v8::Object> target,
                                         v8::Local<v8::Value> unused,
                                         v8::Local<v8::Context> context,
                                         void* priv);
  static void RegisterExternalReferences(ExternalReferenceRegistry* registry);
};

class Database : public BaseObject {
 public:
  enum InternalFields {
    kAuthorizerCallback = BaseObject::kInternalFieldCount,
    kLimitsObject,
    kInternalFieldCount
  };

  Database(Environment* env,
           v8::Local<v8::Object> object,
           DatabaseOpenConfiguration&& open_config,
           bool open,
           bool allow_load_extension);
  void MemoryInfo(MemoryTracker* tracker) const override;
  static void New(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Open(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void IsOpenGetter(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void IsTransactionGetter(
      const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Close(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Dispose(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Prepare(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Exec(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void CreateTagStore(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Location(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void CustomFunction(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void AggregateFunction(
      const v8::FunctionCallbackInfo<v8::Value>& args);
  static void CreateSession(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void ApplyChangeset(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void EnableLoadExtension(
      const v8::FunctionCallbackInfo<v8::Value>& args);
  static void EnableDefensive(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void LimitsGetter(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void LoadExtension(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Serialize(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Deserialize(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void SetAuthorizer(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void CreateModule(const v8::FunctionCallbackInfo<v8::Value>& args);
  static int AuthorizerCallback(void* user_data,
                                int action_code,
                                const char* param1,
                                const char* param2,
                                const char* param3,
                                const char* param4);
  static int TraceCallback(unsigned int type,
                           void* user_data,
                           void* p,
                           void* x);
  void FinalizeStatements();
  void RemoveBackup(BackupJob* backup);
  void AddBackup(BackupJob* backup);
  void FinalizeBackups();
  void TrackStatement(Statement* statement);
  void UntrackStatement(Statement* statement);
  bool IsOpen();
  // SQL functions are one of several paths by which SQLite can invoke JS.
  size_t GetUserDefinedFunctionCount() const {
    return user_defined_functions_.size();
  }
  bool use_big_ints() const { return open_config_.get_use_big_ints(); }
  bool return_arrays() const { return open_config_.get_return_arrays(); }
  bool allow_bare_named_params() const {
    return open_config_.get_allow_bare_named_params();
  }
  bool allow_unknown_named_params() const {
    return open_config_.get_allow_unknown_named_params();
  }
  sqlite3* Connection();
  void SetLimit(int sqlite_limit_id, int value);

  // In some situations, such as when using custom functions, it is possible
  // that SQLite reports an error while JavaScript already has a pending
  // exception. In this case, the SQLite error should be ignored. These methods
  // enable that use case.
  void SetIgnoreNextSQLiteError(bool ignore);
  bool ShouldIgnoreSQLiteError();
  void EnableTracing();
  void DisableTracing();

  void IncrementCallbackDepth() { ++callback_depth_; }
  void DecrementCallbackDepth() { --callback_depth_; }
  bool IsInCallback() const { return callback_depth_ > 0; }

  void IncrementDestructorDepth() { ++destructor_depth_; }
  void DecrementDestructorDepth() { --destructor_depth_; }
  bool IsInDestructor() const { return destructor_depth_ > 0; }

  // SQLite reaches back into JavaScript from inside its pre-update hook, while
  // it is still walking this connection's session list. Session objects are
  // weak, so a garbage collection during such a callback could collect one and
  // free memory SQLite is still using. Returns a strong reference to every
  // attached session so that a callback can hold them for its duration.
  std::vector<BaseObjectPtr<Session>> PinSessions() const;

  // SQLite forbids an authorizer callback from doing anything that modifies
  // the database connection that invoked it, which includes preparing and
  // stepping statements. See https://www.sqlite.org/c3ref/set_authorizer.html.
  void IncrementAuthorizerDepth() { ++authorizer_depth_; }
  void DecrementAuthorizerDepth() { --authorizer_depth_; }
  bool IsInAuthorizerCallback() const { return authorizer_depth_ > 0; }

  // A callback must not finalize the statement being stepped. Other statements
  // are safe unless they are busy during an authorizer callback.
  void PushSteppingStatement(sqlite3_stmt* stmt) {
    stepping_statements_.push_back(stmt);
  }
  void PopSteppingStatement() { stepping_statements_.pop_back(); }
  bool IsSteppingStatement(sqlite3_stmt* stmt) const {
    return std::find(stepping_statements_.begin(),
                     stepping_statements_.end(),
                     stmt) != stepping_statements_.end();
  }

  void IncrementTraceSuppressionDepth() { ++trace_suppression_depth_; }
  void DecrementTraceSuppressionDepth() { --trace_suppression_depth_; }
  bool AreTraceEventsSuppressed() const { return trace_suppression_depth_ > 0; }

  SET_MEMORY_INFO_NAME(Database)
  SET_SELF_SIZE(Database)

 private:
  bool Open();
  void DeleteSessions();

  ~Database() override;
  DatabaseOpenConfiguration open_config_;
  bool allow_load_extension_;
  bool enable_load_extension_;
  ConnectionPtr connection_;
  bool ignore_next_sqlite_error_;
  int callback_depth_ = 0;
  int destructor_depth_ = 0;
  int authorizer_depth_ = 0;
  int trace_suppression_depth_ = 0;
  std::vector<sqlite3_stmt*> stepping_statements_;

  // SQLite owns these scalar and aggregate/window function registrations. Its
  // destroy callbacks untrack replaced functions and failed registrations.
  std::unordered_set<const void*> user_defined_functions_;
  std::set<BackupJob*> backups_;
  std::unordered_set<Session*> sessions_;
  std::unordered_set<Statement*> statements_;
  // Weak ref: BindingData is the sole owner of Channels, so a strong ref here
  // would outlive the binding that backs it during environment cleanup.
  BaseObjectWeakPtr<diagnostics_channel::Channel> trace_channel_;

  friend class UserDefinedFunction;
  friend class CustomAggregate;
  friend class DatabaseLimits;
  friend class Session;
  friend class SQLTagStore;
  friend class StatementExecutionHelper;
  friend class VirtualTableModule;
};

class Statement : public BaseObject {
 public:
  Statement(Environment* env,
            v8::Local<v8::Object> object,
            BaseObjectPtr<Database> db,
            StatementPtr stmt);
  void MemoryInfo(MemoryTracker* tracker) const override;
  static v8::Local<v8::FunctionTemplate> GetConstructorTemplate(
      Environment* env);
  static BaseObjectPtr<Statement> Create(Environment* env,
                                         BaseObjectPtr<Database> db,
                                         StatementPtr stmt);
  static void All(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Iterate(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Get(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Run(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Columns(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void SourceSQLGetter(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void ExpandedSQLGetter(
      const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Stat(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void ResetStats(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void SetAllowBareNamedParameters(
      const v8::FunctionCallbackInfo<v8::Value>& args);
  static void SetAllowUnknownNamedParameters(
      const v8::FunctionCallbackInfo<v8::Value>& args);
  static void SetReadBigInts(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void SetReturnArrays(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Close(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Dispose(const v8::FunctionCallbackInfo<v8::Value>& args);
  v8::MaybeLocal<v8::Value> ColumnToValue(const int column);
  v8::MaybeLocal<v8::Name> ColumnNameToName(const int column);
  // Call after sqlite3_step(), which may re-prepare, and before RowToObject.
  bool UpdateRowCache();
  v8::MaybeLocal<v8::Object> RowToObject(v8::LocalVector<v8::Value>* values);
  void Finalize();
  bool IsFinalized();

  SET_MEMORY_INFO_NAME(Statement)
  SET_SELF_SIZE(Statement)

 private:
  ~Statement() override;
  void Close();
  BaseObjectPtr<Database> db_;
  StatementPtr statement_;
  bool return_arrays_ = false;
  bool use_big_ints_;
  bool allow_bare_named_params_;
  bool allow_unknown_named_params_;
  uint64_t reset_generation_ = 0;
  std::optional<std::map<std::string, std::string>> bare_named_params_;
  inline int ResetStatement();
  std::vector<v8::Global<v8::Name>> cached_column_names_;
  int cached_column_names_reprepare_count_ = -1;
  // Set instead of cached_column_names_ when the names fit a template.
  v8::Global<v8::DictionaryTemplate> cached_row_template_;
  void InvalidateColumnNameCache();
  bool BindParams(const v8::FunctionCallbackInfo<v8::Value>& args);
  bool BindValue(const v8::Local<v8::Value>& value, const int index);

  friend class Database;
  friend class StatementIterator;
  friend class SQLTagStore;
  friend class StatementExecutionHelper;
};

class StatementIterator : public BaseObject {
 public:
  StatementIterator(Environment* env,
                    v8::Local<v8::Object> object,
                    BaseObjectPtr<Statement> stmt);
  void MemoryInfo(MemoryTracker* tracker) const override;
  static v8::Local<v8::FunctionTemplate> GetConstructorTemplate(
      Environment* env);
  static BaseObjectPtr<StatementIterator> Create(Environment* env,
                                                 BaseObjectPtr<Statement> stmt);
  static void Next(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Return(const v8::FunctionCallbackInfo<v8::Value>& args);

  SET_MEMORY_INFO_NAME(StatementIterator)
  SET_SELF_SIZE(StatementIterator)

 private:
  ~StatementIterator() override;
  BaseObjectPtr<Statement> stmt_;
  bool done_;
  uint64_t statement_reset_generation_;
};

using Sqlite3ChangesetGenFunc = int (*)(sqlite3_session*, int*, void**);

class Session : public BaseObject {
 public:
  Session(Environment* env,
          v8::Local<v8::Object> object,
          BaseObjectPtr<Database> database,
          SessionPtr session);
  ~Session() override;
  template <Sqlite3ChangesetGenFunc sqliteChangesetFunc>
  static void Changeset(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Close(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Dispose(const v8::FunctionCallbackInfo<v8::Value>& args);
  static v8::Local<v8::FunctionTemplate> GetConstructorTemplate(
      Environment* env);
  static BaseObjectPtr<Session> Create(Environment* env,
                                       BaseObjectPtr<Database> database,
                                       SessionPtr session);

  void MemoryInfo(MemoryTracker* tracker) const override;
  SET_MEMORY_INFO_NAME(Session)
  SET_SELF_SIZE(Session)

 private:
  void Delete();
  SessionPtr session_;
  BaseObjectPtr<Database> database_;  // The Parent Database
  bool is_generating_changeset_ = false;

  friend class Database;
};

class SQLTagStore : public BaseObject {
 public:
  enum InternalFields {
    kDatabaseObject = BaseObject::kInternalFieldCount,
    kInternalFieldCount
  };

  SQLTagStore(Environment* env,
              v8::Local<v8::Object> object,
              BaseObjectWeakPtr<Database> database,
              int capacity);
  ~SQLTagStore() override;
  static BaseObjectPtr<SQLTagStore> Create(Environment* env,
                                           BaseObjectWeakPtr<Database> database,
                                           int capacity);
  static v8::Local<v8::FunctionTemplate> GetConstructorTemplate(
      Environment* env);
  static void All(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Get(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Iterate(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Run(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Clear(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void CapacityGetter(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void DatabaseGetter(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void SizeGetter(const v8::FunctionCallbackInfo<v8::Value>& args);
  void MemoryInfo(MemoryTracker* tracker) const override;
  SET_MEMORY_INFO_NAME(SQLTagStore)
  SET_SELF_SIZE(SQLTagStore)

 private:
  static BaseObjectPtr<Statement> PrepareStatement(
      const v8::FunctionCallbackInfo<v8::Value>& args);
  static bool ResetAndBindStatement(
      Environment* env,
      Statement* stmt,
      const v8::FunctionCallbackInfo<v8::Value>& args);
  BaseObjectWeakPtr<Database> database_;
  LRUCache<std::string, BaseObjectPtr<Statement>> sql_tags_;
  friend class StatementExecutionHelper;
};

// Guards a window in which SQLite hands control back to JavaScript. Construct
// it before allocating anything on the V8 heap, since the pinned sessions
// below are what keep a garbage collection during that window safe.
class CallbackDepthGuard {
 public:
  explicit CallbackDepthGuard(Database* db)
      : db_(db), pinned_sessions_(db->PinSessions()) {
    db_->IncrementCallbackDepth();
  }
  ~CallbackDepthGuard() { db_->DecrementCallbackDepth(); }
  CallbackDepthGuard(const CallbackDepthGuard&) = delete;
  CallbackDepthGuard& operator=(const CallbackDepthGuard&) = delete;

 private:
  Database* db_;
  std::vector<BaseObjectPtr<Session>> pinned_sessions_;
};

// Marks a window in which SQLite is being torn down from a C++ destructor.
// Those destructors run from V8 garbage collection callbacks, where executing
// JavaScript is forbidden, so callbacks reached through them must not call back
// into JavaScript.
class DestructorScope {
 public:
  explicit DestructorScope(Database* db) : db_(db) {
    db_->IncrementDestructorDepth();
  }
  ~DestructorScope() { db_->DecrementDestructorDepth(); }
  DestructorScope(const DestructorScope&) = delete;
  DestructorScope& operator=(const DestructorScope&) = delete;

 private:
  Database* db_;
};

class TraceEventSuppressionGuard {
 public:
  explicit TraceEventSuppressionGuard(Database* db) : db_(db) {
    db_->IncrementTraceSuppressionDepth();
  }
  ~TraceEventSuppressionGuard() { db_->DecrementTraceSuppressionDepth(); }
  TraceEventSuppressionGuard(const TraceEventSuppressionGuard&) = delete;
  TraceEventSuppressionGuard& operator=(const TraceEventSuppressionGuard&) =
      delete;

 private:
  Database* db_;
};

class SteppingStatementGuard {
 public:
  SteppingStatementGuard(Database* db, sqlite3_stmt* stmt) : db_(db) {
    db_->PushSteppingStatement(stmt);
  }
  ~SteppingStatementGuard() { db_->PopSteppingStatement(); }
  SteppingStatementGuard(const SteppingStatementGuard&) = delete;
  SteppingStatementGuard& operator=(const SteppingStatementGuard&) = delete;

 private:
  Database* db_;
};

class AuthorizerDepthGuard {
 public:
  explicit AuthorizerDepthGuard(Database* db) : db_(db) {
    db_->IncrementAuthorizerDepth();
  }
  ~AuthorizerDepthGuard() { db_->DecrementAuthorizerDepth(); }
  AuthorizerDepthGuard(const AuthorizerDepthGuard&) = delete;
  AuthorizerDepthGuard& operator=(const AuthorizerDepthGuard&) = delete;

 private:
  Database* db_;
};

class UserDefinedFunction {
 public:
  UserDefinedFunction(Environment* env,
                      v8::Local<v8::Function> fn,
                      BaseObjectWeakPtr<Database> db,
                      bool use_bigint_args);
  ~UserDefinedFunction();
  static void xFunc(sqlite3_context* ctx, int argc, sqlite3_value** argv);
  static void xDestroy(void* self);

 private:
  Environment* env_;
  v8::Global<v8::Function> fn_;
  BaseObjectWeakPtr<Database> db_;
  bool use_bigint_args_;
};

class DatabaseLimits : public BaseObject {
 public:
  DatabaseLimits(Environment* env,
                 v8::Local<v8::Object> object,
                 BaseObjectWeakPtr<Database> database);
  ~DatabaseLimits() override;

  void MemoryInfo(MemoryTracker* tracker) const override;
  static v8::Local<v8::ObjectTemplate> GetTemplate(Environment* env);
  static BaseObjectPtr<DatabaseLimits> Create(
      Environment* env, BaseObjectWeakPtr<Database> database);

  static v8::Intercepted LimitsGetter(
      v8::Local<v8::Name> property,
      const v8::PropertyCallbackInfo<v8::Value>& info);
  static v8::Intercepted LimitsSetter(
      v8::Local<v8::Name> property,
      v8::Local<v8::Value> value,
      const v8::PropertyCallbackInfo<v8::Boolean>& info);
  static v8::Intercepted LimitsQuery(
      v8::Local<v8::Name> property,
      const v8::PropertyCallbackInfo<v8::Integer>& info);
  static void LimitsEnumerator(const v8::PropertyCallbackInfo<v8::Array>& info);

  SET_MEMORY_INFO_NAME(DatabaseLimits)
  SET_SELF_SIZE(DatabaseLimits)

 private:
  BaseObjectWeakPtr<Database> database_;
};

struct NodeVTab {
  sqlite3_vtab base;
  class VirtualTableModule* module;
};

struct NodeVTabCursor {
  sqlite3_vtab_cursor base;
  class VirtualTableModule* module;
  v8::Global<v8::Object> iterator;
  v8::Global<v8::Value> current_row;
  // The value each hidden column was constrained to, indexed by schema column
  // index and empty for visible columns. These are owned copies, since the
  // values SQLite passes to xFilter are only valid for that call.
  std::vector<sqlite3_value*> hidden_values;
  sqlite3_int64 rowid;
  bool done;
};

class VirtualTableModule {
 public:
  VirtualTableModule(Environment* env,
                     BaseObjectWeakPtr<Database> db,
                     v8::Local<v8::Function> rows_fn,
                     std::string&& schema_sql,
                     int num_columns,
                     std::vector<int>&& hidden_col_indices,
                     bool use_bigint_args,
                     bool direct_only);
  ~VirtualTableModule();

  static int xCreate(sqlite3* db,
                     void* pAux,
                     int argc,
                     const char* const* argv,
                     sqlite3_vtab** ppVTab,
                     char** pzErr);
  static int xBestIndex(sqlite3_vtab* pVTab, sqlite3_index_info* pInfo);
  static int xDisconnect(sqlite3_vtab* pVTab);
  static int xDestroy(sqlite3_vtab* pVTab);
  static int xOpen(sqlite3_vtab* pVTab, sqlite3_vtab_cursor** ppCursor);
  static int xClose(sqlite3_vtab_cursor* pCursor);
  static int xFilter(sqlite3_vtab_cursor* pCursor,
                     int idxNum,
                     const char* idxStr,
                     int argc,
                     sqlite3_value** argv);
  static int xNext(sqlite3_vtab_cursor* pCursor);
  static int xEof(sqlite3_vtab_cursor* pCursor);
  static int xColumn(sqlite3_vtab_cursor* pCursor, sqlite3_context* ctx, int i);
  static int xRowid(sqlite3_vtab_cursor* pCursor, sqlite3_int64* pRowid);
  static void xDestroyModule(void* pAux);

 private:
  // Suppresses the SQLite error text so the pending JavaScript exception is
  // what surfaces to the caller. Always returns SQLITE_ERROR.
  int PropagateJSError();

  // Reports a violation of the iteration protocol by the `rows` function.
  // Unlike PropagateJSError there is no JavaScript exception to surface, so an
  // error message has to be supplied. Always returns SQLITE_ERROR.
  static int ReportProtocolError(sqlite3_vtab* vtab, const char* message);

  // False while the database is being torn down from a destructor, which runs
  // from a garbage collection callback where JavaScript cannot be executed.
  bool CanCallIntoJS() const;

  // Runs the iterator's return() method so generator `finally` blocks still run
  // when an iterator is abandoned while suspended. Returns true if the return()
  // threw; the exception is re-thrown for the caller to surface.
  bool CloseIterator(NodeVTabCursor* cursor);

  static void ReleaseHiddenValues(NodeVTabCursor* cursor);

  Environment* env_;
  BaseObjectWeakPtr<Database> db_;
  v8::Global<v8::Function> rows_fn_;
  std::string schema_sql_;
  int num_columns_;
  std::vector<int> hidden_col_indices_;
  // Maps schema column index to row array index for visible columns.
  // Hidden columns are mapped to -1.
  std::vector<int> col_index_map_;
  bool use_bigint_args_;
  bool direct_only_;
  sqlite3_module module_def_;

  friend class Database;
};

}  // namespace sqlite
}  // namespace node

#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
#endif  // SRC_NODE_SQLITE_H_