text: // Copyright Joyent, Inc. and other Node contributors.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a
  // copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to permit
  // persons to whom the Software is furnished to do so, subject to the
  // following conditions:
  //
  // The above copyright notice and this permission notice shall be included
  // in all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
  // NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
  // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  // USE OR OTHER DEALINGS IN THE SOFTWARE.
  
  #ifndef SRC_ENV_H_
  #define SRC_ENV_H_
  
  #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
  
  #include "aliased_buffer.h"
  #if HAVE_INSPECTOR
  #include "inspector_agent.h"
  #endif
  #include "handle_wrap.h"
  #include "req_wrap.h"
  #include "util.h"
  #include "uv.h"
  #include "v8.h"
  #include "node.h"
  #include "node_options.h"
  #include "node_http2_state.h"
  
  #include <list>
  #include <stdint.h>
  #include <vector>
  #include <unordered_map>
  #include <unordered_set>
  
  struct nghttp2_rcbuf;
  
  namespace node {
  
  namespace contextify {
  class ContextifyScript;
  }
  
  namespace fs {
  class FileHandleReadWrap;
  }
  
  namespace performance {
  class performance_state;
  }
  
  namespace tracing {
  class AgentWriterHandle;
  }
  
  namespace worker {
  class Worker;
  }
  
  namespace loader {
  class ModuleWrap;
  
  struct PackageConfig {
    enum class Exists { Yes, No };
    enum class IsValid { Yes, No };
    enum class HasMain { Yes, No };
  
    Exists exists;
    IsValid is_valid;
    HasMain has_main;
    std::string main;
  };
  }  // namespace loader
  
  // The number of items passed to push_values_to_array_function has diminishing
  // returns around 8. This should be used at all call sites using said function.
  #ifndef NODE_PUSH_VAL_TO_ARRAY_MAX
  #define NODE_PUSH_VAL_TO_ARRAY_MAX 8
  #endif
  
  // PER_ISOLATE_* macros: We have a lot of per-isolate properties
  // and adding and maintaining their getters and setters by hand would be
  // difficult so let's make the preprocessor generate them for us.
  //
  // In each macro, `V` is expected to be the name of a macro or function which
  // accepts the number of arguments provided in each tuple in the macro body,
  // typically two. The named function will be invoked against each tuple.
  //
  // Make sure that any macro V defined for use with the PER_ISOLATE_* macros is
  // undefined again after use.
  
  // Private symbols are per-isolate primitives but Environment proxies them
  // for the sake of convenience.  Strings should be ASCII-only and have a
  // "node:" prefix to avoid name clashes with third-party code.
  #define PER_ISOLATE_PRIVATE_SYMBOL_PROPERTIES(V)                              \
    V(alpn_buffer_private_symbol, "node:alpnBuffer")                            \
    V(arrow_message_private_symbol, "node:arrowMessage")                        \
    V(contextify_context_private_symbol, "node:contextify:context")             \
    V(contextify_global_private_symbol, "node:contextify:global")               \
    V(decorated_private_symbol, "node:decorated")                               \
    V(napi_env, "node:napi:env")                                                \
    V(napi_wrapper, "node:napi:wrapper")                                        \
    V(sab_lifetimepartner_symbol, "node:sharedArrayBufferLifetimePartner")      \
  
  // Symbols are per-isolate primitives but Environment proxies them
  // for the sake of convenience.
  #define PER_ISOLATE_SYMBOL_PROPERTIES(V)                                      \
    V(handle_onclose_symbol, "handle_onclose")                                  \
    V(oninit_symbol, "oninit")                                                  \
    V(owner_symbol, "owner")                                                    \
  
  // Strings are per-isolate primitives but Environment proxies them
  // for the sake of convenience.  Strings should be ASCII-only.
  #define PER_ISOLATE_STRING_PROPERTIES(V)                                      \
    V(address_string, "address")                                                \
    V(aliases_string, "aliases")                                                \
    V(args_string, "args")                                                      \
    V(async, "async")                                                           \
    V(async_ids_stack_string, "async_ids_stack")                                \
    V(buffer_string, "buffer")                                                  \
    V(bytes_parsed_string, "bytesParsed")                                       \
    V(bytes_read_string, "bytesRead")                                           \
    V(bytes_string, "bytes")                                                    \
    V(bytes_written_string, "bytesWritten")                                     \
    V(cached_data_produced_string, "cachedDataProduced")                        \
    V(cached_data_rejected_string, "cachedDataRejected")                        \
    V(cached_data_string, "cachedData")                                         \
    V(change_string, "change")                                                  \
    V(channel_string, "channel")                                                \
    V(chunks_sent_since_last_write_string, "chunksSentSinceLastWrite")          \
    V(code_string, "code")                                                      \
    V(constants_string, "constants")                                            \
    V(cwd_string, "cwd")                                                        \
    V(dest_string, "dest")                                                      \
    V(destroyed_string, "destroyed")                                            \
    V(detached_string, "detached")                                              \
    V(dns_a_string, "A")                                                        \
    V(dns_aaaa_string, "AAAA")                                                  \
    V(dns_cname_string, "CNAME")                                                \
    V(dns_mx_string, "MX")                                                      \
    V(dns_naptr_string, "NAPTR")                                                \
    V(dns_ns_string, "NS")                                                      \
    V(dns_ptr_string, "PTR")                                                    \
    V(dns_soa_string, "SOA")                                                    \
    V(dns_srv_string, "SRV")                                                    \
    V(dns_txt_string, "TXT")                                                    \
    V(duration_string, "duration")                                              \
    V(emit_warning_string, "emitWarning")                                       \
    V(encoding_string, "encoding")                                              \
    V(entries_string, "entries")                                                \
    V(entry_type_string, "entryType")                                           \
    V(env_pairs_string, "envPairs")                                             \
    V(env_var_settings_string, "envVarSettings")                                \
    V(errno_string, "errno")                                                    \
    V(error_string, "error")                                                    \
    V(exchange_string, "exchange")                                              \
    V(exit_code_string, "exitCode")                                             \
    V(expire_string, "expire")                                                  \
    V(exponent_string, "exponent")                                              \
    V(exports_string, "exports")                                                \
    V(ext_key_usage_string, "ext_key_usage")                                    \
    V(external_stream_string, "_externalStream")                                \
    V(family_string, "family")                                                  \
    V(fatal_exception_string, "_fatalException")                                \
    V(fd_string, "fd")                                                          \
    V(file_string, "file")                                                      \
    V(fingerprint256_string, "fingerprint256")                                  \
    V(fingerprint_string, "fingerprint")                                        \
    V(flags_string, "flags")                                                    \
    V(fragment_string, "fragment")                                              \
    V(get_data_clone_error_string, "_getDataCloneError")                        \
    V(get_shared_array_buffer_id_string, "_getSharedArrayBufferId")             \
    V(gid_string, "gid")                                                        \
    V(handle_string, "handle")                                                  \
    V(help_text_string, "helpText")                                             \
    V(homedir_string, "homedir")                                                \
    V(host_string, "host")                                                      \
    V(hostmaster_string, "hostmaster")                                          \
    V(ignore_string, "ignore")                                                  \
    V(infoaccess_string, "infoAccess")                                          \
    V(inherit_string, "inherit")                                                \
    V(input_string, "input")                                                    \
    V(internal_string, "internal")                                              \
    V(ipv4_string, "IPv4")                                                      \
    V(ipv6_string, "IPv6")                                                      \
    V(isclosing_string, "isClosing")                                            \
    V(issuer_string, "issuer")                                                  \
    V(issuercert_string, "issuerCertificate")                                   \
    V(kill_signal_string, "killSignal")                                         \
    V(kind_string, "kind")                                                      \
    V(mac_string, "mac")                                                        \
    V(main_string, "main")                                                      \
    V(max_buffer_string, "maxBuffer")                                           \
    V(message_port_constructor_string, "MessagePort")                           \
    V(message_port_string, "messagePort")                                       \
    V(message_string, "message")                                                \
    V(minttl_string, "minttl")                                                  \
    V(modulus_string, "modulus")                                                \
    V(name_string, "name")                                                      \
    V(netmask_string, "netmask")                                                \
    V(nsname_string, "nsname")                                                  \
    V(ocsp_request_string, "OCSPRequest")                                       \
    V(onaltsvc_string, "onaltsvc")                                              \
    V(oncertcb_string, "oncertcb")                                              \
    V(onchange_string, "onchange")                                              \
    V(onclienthello_string, "onclienthello")                                    \
    V(oncomplete_string, "oncomplete")                                          \
    V(onconnection_string, "onconnection")                                      \
    V(ondone_string, "ondone")                                                  \
    V(onerror_string, "onerror")                                                \
    V(onexit_string, "onexit")                                                  \
    V(onframeerror_string, "onframeerror")                                      \
    V(ongetpadding_string, "ongetpadding")                                      \
    V(ongoawaydata_string, "ongoawaydata")                                      \
    V(onhandshakedone_string, "onhandshakedone")                                \
    V(onhandshakestart_string, "onhandshakestart")                              \
    V(onheaders_string, "onheaders")                                            \
    V(onmessage_string, "onmessage")                                            \
    V(onnewsession_string, "onnewsession")                                      \
    V(onocspresponse_string, "onocspresponse")                                  \
    V(onorigin_string, "onorigin")                                              \
    V(onping_string, "onping")                                                  \
    V(onpriority_string, "onpriority")                                          \
    V(onread_string, "onread")                                                  \
    V(onreadstart_string, "onreadstart")                                        \
    V(onreadstop_string, "onreadstop")                                          \
    V(onsettings_string, "onsettings")                                          \
    V(onshutdown_string, "onshutdown")                                          \
    V(onsignal_string, "onsignal")                                              \
    V(onstreamclose_string, "onstreamclose")                                    \
    V(ontrailers_string, "ontrailers")                                          \
    V(onunpipe_string, "onunpipe")                                              \
    V(onwrite_string, "onwrite")                                                \
    V(openssl_error_stack, "opensslErrorStack")                                 \
    V(options_string, "options")                                                \
    V(order_string, "order")                                                    \
    V(output_string, "output")                                                  \
    V(parse_error_string, "Parse Error")                                        \
    V(password_string, "password")                                              \
    V(path_string, "path")                                                      \
    V(pending_handle_string, "pendingHandle")                                   \
    V(pid_string, "pid")                                                        \
    V(pipe_source_string, "pipeSource")                                         \
    V(pipe_string, "pipe")                                                      \
    V(pipe_target_string, "pipeTarget")                                         \
    V(port1_string, "port1")                                                    \
    V(port2_string, "port2")                                                    \
    V(port_string, "port")                                                      \
    V(preference_string, "preference")                                          \
    V(priority_string, "priority")                                              \
    V(promise_string, "promise")                                                \
    V(pubkey_string, "pubkey")                                                  \
    V(query_string, "query")                                                    \
    V(raw_string, "raw")                                                        \
    V(read_host_object_string, "_readHostObject")                               \
    V(readable_string, "readable")                                              \
    V(refresh_string, "refresh")                                                \
    V(regexp_string, "regexp")                                                  \
    V(rename_string, "rename")                                                  \
    V(replacement_string, "replacement")                                        \
    V(retry_string, "retry")                                                    \
    V(scheme_string, "scheme")                                                  \
    V(scopeid_string, "scopeid")                                                \
    V(serial_number_string, "serialNumber")                                     \
    V(serial_string, "serial")                                                  \
    V(servername_string, "servername")                                          \
    V(service_string, "service")                                                \
    V(session_id_string, "sessionId")                                           \
    V(shell_string, "shell")                                                    \
    V(signal_string, "signal")                                                  \
    V(sink_string, "sink")                                                      \
    V(size_string, "size")                                                      \
    V(sni_context_err_string, "Invalid SNI context")                            \
    V(sni_context_string, "sni_context")                                        \
    V(source_string, "source")                                                  \
    V(stack_string, "stack")                                                    \
    V(start_time_string, "startTime")                                           \
    V(status_string, "status")                                                  \
    V(stdio_string, "stdio")                                                    \
    V(subject_string, "subject")                                                \
    V(subjectaltname_string, "subjectaltname")                                  \
    V(syscall_string, "syscall")                                                \
    V(thread_id_string, "threadId")                                             \
    V(ticketkeycallback_string, "onticketkeycallback")                          \
    V(timeout_string, "timeout")                                                \
    V(tls_ticket_string, "tlsTicket")                                           \
    V(ttl_string, "ttl")                                                        \
    V(type_string, "type")                                                      \
    V(uid_string, "uid")                                                        \
    V(unknown_string, "<unknown>")                                              \
    V(url_string, "url")                                                        \
    V(username_string, "username")                                              \
    V(valid_from_string, "valid_from")                                          \
    V(valid_to_string, "valid_to")                                              \
    V(value_string, "value")                                                    \
    V(verify_error_string, "verifyError")                                       \
    V(version_string, "version")                                                \
    V(weight_string, "weight")                                                  \
    V(windows_hide_string, "windowsHide")                                       \
    V(windows_verbatim_arguments_string, "windowsVerbatimArguments")            \
    V(wrap_string, "wrap")                                                      \
    V(writable_string, "writable")                                              \
    V(write_host_object_string, "_writeHostObject")                             \
    V(write_queue_size_string, "writeQueueSize")                                \
    V(x_forwarded_string, "x-forwarded-for")                                    \
    V(zero_return_string, "ZERO_RETURN")                                        \
  
  #define ENVIRONMENT_STRONG_PERSISTENT_PROPERTIES(V)                           \
    V(as_external, v8::External)                                                \
    V(async_hooks_after_function, v8::Function)                                 \
    V(async_hooks_before_function, v8::Function)                                \
    V(async_hooks_binding, v8::Object)                                          \
    V(async_hooks_destroy_function, v8::Function)                               \
    V(async_hooks_init_function, v8::Function)                                  \
    V(async_hooks_promise_resolve_function, v8::Function)                       \
    V(async_wrap_ctor_template, v8::FunctionTemplate)                           \
    V(async_wrap_object_ctor_template, v8::FunctionTemplate)                    \
    V(buffer_prototype_object, v8::Object)                                      \
    V(context, v8::Context)                                                     \
    V(domain_callback, v8::Function)                                            \
    V(domexception_function, v8::Function)                                      \
    V(fd_constructor_template, v8::ObjectTemplate)                              \
    V(fdclose_constructor_template, v8::ObjectTemplate)                         \
    V(filehandlereadwrap_template, v8::ObjectTemplate)                          \
    V(fs_use_promises_symbol, v8::Symbol)                                       \
    V(fsreqpromise_constructor_template, v8::ObjectTemplate)                    \
    V(handle_wrap_ctor_template, v8::FunctionTemplate)                          \
    V(host_import_module_dynamically_callback, v8::Function)                    \
    V(host_initialize_import_meta_object_callback, v8::Function)                \
    V(http2ping_constructor_template, v8::ObjectTemplate)                       \
    V(http2settings_constructor_template, v8::ObjectTemplate)                   \
    V(http2stream_constructor_template, v8::ObjectTemplate)                     \
    V(immediate_callback_function, v8::Function)                                \
    V(inspector_console_api_object, v8::Object)                                 \
    V(libuv_stream_wrap_ctor_template, v8::FunctionTemplate)                    \
    V(message_port, v8::Object)                                                 \
    V(message_port_constructor_template, v8::FunctionTemplate)                  \
    V(performance_entry_callback, v8::Function)                                 \
    V(performance_entry_template, v8::Function)                                 \
    V(pipe_constructor_template, v8::FunctionTemplate)                          \
    V(process_object, v8::Object)                                               \
    V(promise_handler_function, v8::Function)                                   \
    V(promise_wrap_template, v8::ObjectTemplate)                                \
    V(push_values_to_array_function, v8::Function)                              \
    V(sab_lifetimepartner_constructor_template, v8::FunctionTemplate)           \
    V(script_context_constructor_template, v8::FunctionTemplate)                \
    V(script_data_constructor_function, v8::Function)                           \
    V(secure_context_constructor_template, v8::FunctionTemplate)                \
    V(shutdown_wrap_template, v8::ObjectTemplate)                               \
    V(tcp_constructor_template, v8::FunctionTemplate)                           \
    V(tick_callback_function, v8::Function)                                     \
    V(timers_callback_function, v8::Function)                                   \
    V(tls_wrap_constructor_function, v8::Function)                              \
    V(tty_constructor_template, v8::FunctionTemplate)                           \
    V(udp_constructor_function, v8::Function)                                   \
    V(url_constructor_function, v8::Function)                                   \
    V(write_wrap_template, v8::ObjectTemplate)                                  \
  
  class Environment;
  
  class IsolateData {
   public:
    IsolateData(v8::Isolate* isolate, uv_loop_t* event_loop,
                MultiIsolatePlatform* platform = nullptr,
                uint32_t* zero_fill_field = nullptr);
    ~IsolateData();
    inline uv_loop_t* event_loop() const;
    inline uint32_t* zero_fill_field() const;
    inline MultiIsolatePlatform* platform() const;
    inline std::shared_ptr<PerIsolateOptions> options();
  
  #define VP(PropertyName, StringValue) V(v8::Private, PropertyName)
  #define VY(PropertyName, StringValue) V(v8::Symbol, PropertyName)
  #define VS(PropertyName, StringValue) V(v8::String, PropertyName)
  #define V(TypeName, PropertyName)                                             \
    inline v8::Local<TypeName> PropertyName(v8::Isolate* isolate) const;
    PER_ISOLATE_PRIVATE_SYMBOL_PROPERTIES(VP)
    PER_ISOLATE_SYMBOL_PROPERTIES(VY)
    PER_ISOLATE_STRING_PROPERTIES(VS)
  #undef V
  #undef VS
  #undef VP
  
    std::unordered_map<nghttp2_rcbuf*, v8::Eternal<v8::String>> http2_static_strs;
    inline v8::Isolate* isolate() const;
  
   private:
  #define VP(PropertyName, StringValue) V(v8::Private, PropertyName)
  #define VY(PropertyName, StringValue) V(v8::Symbol, PropertyName)
  #define VS(PropertyName, StringValue) V(v8::String, PropertyName)
  #define V(TypeName, PropertyName)                                             \
    v8::Eternal<TypeName> PropertyName ## _;
    PER_ISOLATE_PRIVATE_SYMBOL_PROPERTIES(VP)
    PER_ISOLATE_SYMBOL_PROPERTIES(VY)
    PER_ISOLATE_STRING_PROPERTIES(VS)
  #undef V
  #undef VS
  #undef VP
  
    v8::Isolate* const isolate_;
    uv_loop_t* const event_loop_;
    uint32_t* const zero_fill_field_;
    MultiIsolatePlatform* platform_;
    std::shared_ptr<PerIsolateOptions> options_;
  
    DISALLOW_COPY_AND_ASSIGN(IsolateData);
  };
  
  struct ContextInfo {
    explicit ContextInfo(const std::string& name) : name(name) {}
    const std::string name;
    std::string origin;
    bool is_default = false;
  };
  
  // Listing the AsyncWrap provider types first enables us to cast directly
  // from a provider type to a debug category.
  #define DEBUG_CATEGORY_NAMES(V) \
      NODE_ASYNC_PROVIDER_TYPES(V) \
      V(INSPECTOR_SERVER)
  
  enum class DebugCategory {
  #define V(name) name,
    DEBUG_CATEGORY_NAMES(V)
  #undef V
    CATEGORY_COUNT
  };
  
  class Environment {
   public:
    class AsyncHooks {
     public:
      // Reason for both UidFields and Fields are that one is stored as a double*
      // and the other as a uint32_t*.
      enum Fields {
        kInit,
        kBefore,
        kAfter,
        kDestroy,
        kPromiseResolve,
        kTotals,
        kCheck,
        kStackLength,
        kFieldsCount,
      };
  
      enum UidFields {
        kExecutionAsyncId,
        kTriggerAsyncId,
        kAsyncIdCounter,
        kDefaultTriggerAsyncId,
        kUidFieldsCount,
      };
  
      inline AliasedBuffer<uint32_t, v8::Uint32Array>& fields();
      inline AliasedBuffer<double, v8::Float64Array>& async_id_fields();
      inline AliasedBuffer<double, v8::Float64Array>& async_ids_stack();
  
      inline v8::Local<v8::String> provider_string(int idx);
  
      inline void no_force_checks();
      inline Environment* env();
  
      inline void push_async_ids(double async_id, double trigger_async_id);
      inline bool pop_async_id(double async_id);
      inline void clear_async_id_stack();  // Used in fatal exceptions.
  
      // Used to set the kDefaultTriggerAsyncId in a scope. This is instead of
      // passing the trigger_async_id along with other constructor arguments.
      class DefaultTriggerAsyncIdScope {
       public:
        DefaultTriggerAsyncIdScope() = delete;
        explicit DefaultTriggerAsyncIdScope(Environment* env,
                                            double init_trigger_async_id);
        explicit DefaultTriggerAsyncIdScope(AsyncWrap* async_wrap);
        ~DefaultTriggerAsyncIdScope();
  
       private:
        AsyncHooks* async_hooks_;
        double old_default_trigger_async_id_;
  
        DISALLOW_COPY_AND_ASSIGN(DefaultTriggerAsyncIdScope);
      };
  
  
     private:
      friend class Environment;  // So we can call the constructor.
      inline AsyncHooks();
      // Keep a list of all Persistent strings used for Provider types.
      v8::Eternal<v8::String> providers_[AsyncWrap::PROVIDERS_LENGTH];
      // Keep track of the environment copy itself.
      Environment* env_;
      // Stores the ids of the current execution context stack.
      AliasedBuffer<double, v8::Float64Array> async_ids_stack_;
      // Attached to a Uint32Array that tracks the number of active hooks for
      // each type.
      AliasedBuffer<uint32_t, v8::Uint32Array> fields_;
      // Attached to a Float64Array that tracks the state of async resources.
      AliasedBuffer<double, v8::Float64Array> async_id_fields_;
  
      void grow_async_ids_stack();
  
      DISALLOW_COPY_AND_ASSIGN(AsyncHooks);
    };
  
    class AsyncCallbackScope {
     public:
      AsyncCallbackScope() = delete;
      explicit AsyncCallbackScope(Environment* env);
      ~AsyncCallbackScope();
  
     private:
      Environment* env_;
  
      DISALLOW_COPY_AND_ASSIGN(AsyncCallbackScope);
    };
  
    inline size_t makecallback_depth() const;
  
    class ImmediateInfo {
     public:
      inline AliasedBuffer<uint32_t, v8::Uint32Array>& fields();
      inline uint32_t count() const;
      inline uint32_t ref_count() const;
      inline bool has_outstanding() const;
  
      inline void count_inc(uint32_t increment);
      inline void count_dec(uint32_t decrement);
  
      inline void ref_count_inc(uint32_t increment);
      inline void ref_count_dec(uint32_t decrement);
  
     private:
      friend class Environment;  // So we can call the constructor.
      inline explicit ImmediateInfo(v8::Isolate* isolate);
  
      enum Fields {
        kCount,
        kRefCount,
        kHasOutstanding,
        kFieldsCount
      };
  
      AliasedBuffer<uint32_t, v8::Uint32Array> fields_;
  
      DISALLOW_COPY_AND_ASSIGN(ImmediateInfo);
    };
  
    class TickInfo {
     public:
      inline AliasedBuffer<uint8_t, v8::Uint8Array>& fields();
      inline bool has_scheduled() const;
      inline bool has_promise_rejections() const;
      inline bool has_thrown() const;
  
      inline void promise_rejections_toggle_on();
      inline void set_has_thrown(bool state);
  
     private:
      friend class Environment;  // So we can call the constructor.
      inline explicit TickInfo(v8::Isolate* isolate);
  
      enum Fields {
        kHasScheduled,
        kHasPromiseRejections,
        kHasThrown,
        kFieldsCount
      };
  
      AliasedBuffer<uint8_t, v8::Uint8Array> fields_;
  
      DISALLOW_COPY_AND_ASSIGN(TickInfo);
    };
  
    static inline Environment* GetCurrent(v8::Isolate* isolate);
    static inline Environment* GetCurrent(v8::Local<v8::Context> context);
    static inline Environment* GetCurrent(
        const v8::FunctionCallbackInfo<v8::Value>& info);
  
    template <typename T>
    static inline Environment* GetCurrent(
        const v8::PropertyCallbackInfo<T>& info);
  
    static uv_key_t thread_local_env;
    static inline Environment* GetThreadLocalEnv();
  
    Environment(IsolateData* isolate_data,
                v8::Local<v8::Context> context,
                tracing::AgentWriterHandle* tracing_agent_writer);
    ~Environment();
  
    void Start(const std::vector<std::string>& args,
               const std::vector<std::string>& exec_args,
               bool start_profiler_idle_notifier);
  
    typedef void (*HandleCleanupCb)(Environment* env,
                                    uv_handle_t* handle,
                                    void* arg);
    struct HandleCleanup {
      uv_handle_t* handle_;
      HandleCleanupCb cb_;
      void* arg_;
    };
  
    void RegisterHandleCleanups();
    void CleanupHandles();
    void Exit(int code);
  
    // Register clean-up cb to be called on environment destruction.
    inline void RegisterHandleCleanup(uv_handle_t* handle,
                                      HandleCleanupCb cb,
                                      void* arg);
  
    template <typename T, typename OnCloseCallback>
    inline void CloseHandle(T* handle, OnCloseCallback callback);
  
    inline void AssignToContext(v8::Local<v8::Context> context,
                                const ContextInfo& info);
  
    void StartProfilerIdleNotifier();
    void StopProfilerIdleNotifier();
    inline bool profiler_idle_notifier_started() const;
  
    inline v8::Isolate* isolate() const;
    inline tracing::AgentWriterHandle* tracing_agent_writer() const;
    inline uv_loop_t* event_loop() const;
    inline uint32_t watched_providers() const;
  
    static inline Environment* from_immediate_check_handle(uv_check_t* handle);
    inline uv_check_t* immediate_check_handle();
    inline uv_idle_t* immediate_idle_handle();
  
    inline void IncreaseWaitingRequestCounter();
    inline void DecreaseWaitingRequestCounter();
  
    inline AsyncHooks* async_hooks();
    inline ImmediateInfo* immediate_info();
    inline TickInfo* tick_info();
    inline uint64_t timer_base() const;
  
    inline IsolateData* isolate_data() const;
  
    inline bool printed_error() const;
    inline void set_printed_error(bool value);
  
    void PrintSyncTrace() const;
    inline void set_trace_sync_io(bool value);
  
    // This stores whether the --abort-on-uncaught-exception flag was passed
    // to Node.
    inline bool abort_on_uncaught_exception() const;
    inline void set_abort_on_uncaught_exception(bool value);
    // This is a pseudo-boolean that keeps track of whether an uncaught exception
    // should abort the process or not if --abort-on-uncaught-exception was
    // passed to Node. If the flag was not passed, it is ignored.
    inline AliasedBuffer<uint32_t, v8::Uint32Array>&
    should_abort_on_uncaught_toggle();
  
    // The necessary API for async_hooks.
    inline double new_async_id();
    inline double execution_async_id();
    inline double trigger_async_id();
    inline double get_default_trigger_async_id();
  
    // List of id's that have been destroyed and need the destroy() cb called.
    inline std::vector<double>* destroy_async_id_list();
  
    std::unordered_multimap<int, loader::ModuleWrap*> hash_to_module_map;
    std::unordered_map<uint32_t, loader::ModuleWrap*> id_to_module_map;
    std::unordered_map<uint32_t, contextify::ContextifyScript*>
        id_to_script_map;
  
    inline uint32_t get_next_module_id();
    inline uint32_t get_next_script_id();
  
    std::unordered_map<std::string, const loader::PackageConfig>
        package_json_cache;
  
    inline double* heap_statistics_buffer() const;
    inline void set_heap_statistics_buffer(double* pointer);
  
    inline double* heap_space_statistics_buffer() const;
    inline void set_heap_space_statistics_buffer(double* pointer);
  
    inline char* http_parser_buffer() const;
    inline void set_http_parser_buffer(char* buffer);
    inline bool http_parser_buffer_in_use() const;
    inline void set_http_parser_buffer_in_use(bool in_use);
  
    inline http2::Http2State* http2_state() const;
    inline void set_http2_state(std::unique_ptr<http2::Http2State> state);
  
    inline bool debug_enabled(DebugCategory category) const;
    inline void set_debug_enabled(DebugCategory category, bool enabled);
    void set_debug_categories(const std::string& cats, bool enabled);
  
    inline AliasedBuffer<double, v8::Float64Array>* fs_stats_field_array();
    inline AliasedBuffer<uint64_t, v8::BigUint64Array>*
        fs_stats_field_bigint_array();
  
    // stat fields contains twice the number of entries because `fs.StatWatcher`
    // needs room to store data for *two* `fs.Stats` instances.
    static const int kFsStatsFieldsLength = 14;
  
    inline std::vector<std::unique_ptr<fs::FileHandleReadWrap>>&
        file_handle_read_wrap_freelist();
  
    inline performance::performance_state* performance_state();
    inline std::unordered_map<std::string, uint64_t>* performance_marks();
  
    void CollectExceptionInfo(v8::Local<v8::Value> context,
                              int errorno,
                              const char* syscall = nullptr,
                              const char* message = nullptr,
                              const char* path = nullptr);
  
    void CollectUVExceptionInfo(v8::Local<v8::Value> context,
                                int errorno,
                                const char* syscall = nullptr,
                                const char* message = nullptr,
                                const char* path = nullptr,
                                const char* dest = nullptr);
  
    // If this flag is set, calls into JS (if they would be observable
    // from userland) must be avoided.  This flag does not indicate whether
    // calling into JS is allowed from a VM perspective at this point.
    inline bool can_call_into_js() const;
    inline void set_can_call_into_js(bool can_call_into_js);
  
    inline bool is_main_thread() const;
    inline uint64_t thread_id() const;
    inline void set_thread_id(uint64_t id);
    inline worker::Worker* worker_context() const;
    inline void set_worker_context(worker::Worker* context);
    inline void add_sub_worker_context(worker::Worker* context);
    inline void remove_sub_worker_context(worker::Worker* context);
    void stop_sub_worker_contexts();
    inline bool is_stopping_worker() const;
  
    inline void ThrowError(const char* errmsg);
    inline void ThrowTypeError(const char* errmsg);
    inline void ThrowRangeError(const char* errmsg);
    inline void ThrowErrnoException(int errorno,
                                    const char* syscall = nullptr,
                                    const char* message = nullptr,
                                    const char* path = nullptr);
    inline void ThrowUVException(int errorno,
                                 const char* syscall = nullptr,
                                 const char* message = nullptr,
                                 const char* path = nullptr,
                                 const char* dest = nullptr);
  
    inline v8::Local<v8::FunctionTemplate>
        NewFunctionTemplate(v8::FunctionCallback callback,
                            v8::Local<v8::Signature> signature =
                                v8::Local<v8::Signature>(),
                            v8::ConstructorBehavior behavior =
                                v8::ConstructorBehavior::kAllow,
                            v8::SideEffectType side_effect =
                                v8::SideEffectType::kHasSideEffect);
  
    // Convenience methods for NewFunctionTemplate().
    inline void SetMethod(v8::Local<v8::Object> that,
                          const char* name,
                          v8::FunctionCallback callback);
  
    inline void SetProtoMethod(v8::Local<v8::FunctionTemplate> that,
                               const char* name,
                               v8::FunctionCallback callback);
    inline void SetTemplateMethod(v8::Local<v8::FunctionTemplate> that,
                                  const char* name,
                                  v8::FunctionCallback callback);
  
    // Safe variants denote the function has no side effects.
    inline void SetMethodNoSideEffect(v8::Local<v8::Object> that,
                                      const char* name,
                                      v8::FunctionCallback callback);
    inline void SetProtoMethodNoSideEffect(v8::Local<v8::FunctionTemplate> that,
                                           const char* name,
                                           v8::FunctionCallback callback);
    inline void SetTemplateMethodNoSideEffect(
        v8::Local<v8::FunctionTemplate> that,
        const char* name,
        v8::FunctionCallback callback);
  
    void BeforeExit(void (*cb)(void* arg), void* arg);
    void RunBeforeExitCallbacks();
    void AtExit(void (*cb)(void* arg), void* arg);
    void RunAtExitCallbacks();
  
    // Strings and private symbols are shared across shared contexts
    // The getters simply proxy to the per-isolate primitive.
  #define VP(PropertyName, StringValue) V(v8::Private, PropertyName)
  #define VY(PropertyName, StringValue) V(v8::Symbol, PropertyName)
  #define VS(PropertyName, StringValue) V(v8::String, PropertyName)
  #define V(TypeName, PropertyName)                                             \
    inline v8::Local<TypeName> PropertyName() const;
    PER_ISOLATE_PRIVATE_SYMBOL_PROPERTIES(VP)
    PER_ISOLATE_SYMBOL_PROPERTIES(VY)
    PER_ISOLATE_STRING_PROPERTIES(VS)
  #undef V
  #undef VS
  #undef VY
  #undef VP
  
  #define V(PropertyName, TypeName)                                             \
    inline v8::Local<TypeName> PropertyName() const;                            \
    inline void set_ ## PropertyName(v8::Local<TypeName> value);
    ENVIRONMENT_STRONG_PERSISTENT_PROPERTIES(V)
  #undef V
  
  #if HAVE_INSPECTOR
    inline inspector::Agent* inspector_agent() const {
      return inspector_agent_.get();
    }
  #endif
  
    typedef ListHead<HandleWrap, &HandleWrap::handle_wrap_queue_> HandleWrapQueue;
    typedef ListHead<ReqWrap<uv_req_t>, &ReqWrap<uv_req_t>::req_wrap_queue_>
            ReqWrapQueue;
  
    inline HandleWrapQueue* handle_wrap_queue() { return &handle_wrap_queue_; }
    inline ReqWrapQueue* req_wrap_queue() { return &req_wrap_queue_; }
  
    void AddPromiseHook(promise_hook_func fn, void* arg);
    bool RemovePromiseHook(promise_hook_func fn, void* arg);
    inline bool EmitProcessEnvWarning() {
      bool current_value = emit_env_nonstring_warning_;
      emit_env_nonstring_warning_ = false;
      return current_value;
    }
  
    typedef void (*native_immediate_callback)(Environment* env, void* data);
    // cb will be called as cb(env, data) on the next event loop iteration.
    // obj will be kept alive between now and after the callback has run.
    inline void SetImmediate(native_immediate_callback cb,
                             void* data,
                             v8::Local<v8::Object> obj = v8::Local<v8::Object>());
    inline void SetUnrefImmediate(native_immediate_callback cb,
                                  void* data,
                                  v8::Local<v8::Object> obj =
                                      v8::Local<v8::Object>());
    // This needs to be available for the JS-land setImmediate().
    void ToggleImmediateRef(bool ref);
  
    class ShouldNotAbortOnUncaughtScope {
     public:
      explicit inline ShouldNotAbortOnUncaughtScope(Environment* env);
      inline void Close();
      inline ~ShouldNotAbortOnUncaughtScope();
  
     private:
      Environment* env_;
    };
  
    inline bool inside_should_not_abort_on_uncaught_scope() const;
  
    static inline Environment* ForAsyncHooks(AsyncHooks* hooks);
  
    v8::Local<v8::Value> GetNow();
  
    inline void AddCleanupHook(void (*fn)(void*), void* arg);
    inline void RemoveCleanupHook(void (*fn)(void*), void* arg);
    void RunCleanup();
  
    static void BuildEmbedderGraph(v8::Isolate* isolate,
                                   v8::EmbedderGraph* graph,
                                   void* data);
  
    inline std::shared_ptr<EnvironmentOptions> options();
  
   private:
    inline void CreateImmediate(native_immediate_callback cb,
                                void* data,
                                v8::Local<v8::Object> obj,
                                bool ref);
  
    inline void ThrowError(v8::Local<v8::Value> (*fun)(v8::Local<v8::String>),
                           const char* errmsg);
  
    v8::Isolate* const isolate_;
    IsolateData* const isolate_data_;
    tracing::AgentWriterHandle* const tracing_agent_writer_;
    uv_check_t immediate_check_handle_;
    uv_idle_t immediate_idle_handle_;
    uv_prepare_t idle_prepare_handle_;
    uv_check_t idle_check_handle_;
    bool profiler_idle_notifier_started_ = false;
  
    AsyncHooks async_hooks_;
    ImmediateInfo immediate_info_;
    TickInfo tick_info_;
    const uint64_t timer_base_;
    bool printed_error_;
    bool abort_on_uncaught_exception_;
    bool emit_env_nonstring_warning_;
    size_t makecallback_cntr_;
    std::vector<double> destroy_async_id_list_;
  
    std::shared_ptr<EnvironmentOptions> options_;
  
    uint32_t module_id_counter_ = 0;
    uint32_t script_id_counter_ = 0;
  
    AliasedBuffer<uint32_t, v8::Uint32Array> should_abort_on_uncaught_toggle_;
    int should_not_abort_scope_counter_ = 0;
  
    std::unique_ptr<performance::performance_state> performance_state_;
    std::unordered_map<std::string, uint64_t> performance_marks_;
  
    bool can_call_into_js_ = true;
    uint64_t thread_id_ = 0;
    std::unordered_set<worker::Worker*> sub_worker_contexts_;
  
    static void* kNodeContextTagPtr;
    static int const kNodeContextTag;
  
  #if HAVE_INSPECTOR
    std::unique_ptr<inspector::Agent> inspector_agent_;
  #endif
  
    // handle_wrap_queue_ and req_wrap_queue_ needs to be at a fixed offset from
    // the start of the class because it is used by
    // src/node_postmortem_metadata.cc to calculate offsets and generate debug
    // symbols for Environment, which assumes that the position of members in
    // memory are predictable. For more information please refer to
    // `doc/guides/node-postmortem-support.md`
    friend int GenDebugSymbols();
    HandleWrapQueue handle_wrap_queue_;
    ReqWrapQueue req_wrap_queue_;
    std::list<HandleCleanup> handle_cleanup_queue_;
    int handle_cleanup_waiting_ = 0;
    int request_waiting_ = 0;
  
    double* heap_statistics_buffer_ = nullptr;
    double* heap_space_statistics_buffer_ = nullptr;
  
    char* http_parser_buffer_;
    bool http_parser_buffer_in_use_ = false;
    std::unique_ptr<http2::Http2State> http2_state_;
  
    bool debug_enabled_[static_cast<int>(DebugCategory::CATEGORY_COUNT)] = {0};
  
    AliasedBuffer<double, v8::Float64Array> fs_stats_field_array_;
    AliasedBuffer<uint64_t, v8::BigUint64Array> fs_stats_field_bigint_array_;
  
    std::vector<std::unique_ptr<fs::FileHandleReadWrap>>
        file_handle_read_wrap_freelist_;
  
    worker::Worker* worker_context_ = nullptr;
  
    struct ExitCallback {
      void (*cb_)(void* arg);
      void* arg_;
    };
    std::list<ExitCallback> before_exit_functions_;
  
    std::list<ExitCallback> at_exit_functions_;
  
    struct PromiseHookCallback {
      promise_hook_func cb_;
      void* arg_;
      size_t enable_count_;
    };
    std::vector<PromiseHookCallback> promise_hooks_;
  
    struct NativeImmediateCallback {
      native_immediate_callback cb_;
      void* data_;
      std::unique_ptr<Persistent<v8::Object>> keep_alive_;
      bool refed_;
    };
    std::vector<NativeImmediateCallback> native_immediate_callbacks_;
    void RunAndClearNativeImmediates();
    static void CheckImmediate(uv_check_t* handle);
  
    struct CleanupHookCallback {
      void (*fn_)(void*);
      void* arg_;
  
      // We keep track of the insertion order for these objects, so that we can
      // call the callbacks in reverse order when we are cleaning up.
      uint64_t insertion_order_counter_;
  
      // Only hashes `arg_`, since that is usually enough to identify the hook.
      struct Hash {
        inline size_t operator()(const CleanupHookCallback& cb) const;
      };
  
      // Compares by `fn_` and `arg_` being equal.
      struct Equal {
        inline bool operator()(const CleanupHookCallback& a,
                               const CleanupHookCallback& b) const;
      };
  
      inline BaseObject* GetBaseObject() const;
    };
  
    // Use an unordered_set, so that we have efficient insertion and removal.
    std::unordered_set<CleanupHookCallback,
                       CleanupHookCallback::Hash,
                       CleanupHookCallback::Equal> cleanup_hooks_;
    uint64_t cleanup_hook_counter_ = 0;
  
    static void EnvPromiseHook(v8::PromiseHookType type,
                               v8::Local<v8::Promise> promise,
                               v8::Local<v8::Value> parent);
  
    template <typename T>
    void ForEachBaseObject(T&& iterator);
  
  #define V(PropertyName, TypeName) Persistent<TypeName> PropertyName ## _;
    ENVIRONMENT_STRONG_PERSISTENT_PROPERTIES(V)
  #undef V
  
    DISALLOW_COPY_AND_ASSIGN(Environment);
  };
  
  }  // namespace node
  
  #endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
  
  #endif  // SRC_ENV_H_
  