Chromium 中js navigator对象c++实现分析

一、Navigator 对象

Navigator 对象包含有关浏览器的信息。

前端测试例子：

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>接口测试</title>
</head>
<body>
	
<div id="example"></div>
<script>
txt = "<p>浏览器代号: " + navigator.appCodeName + "</p>";
txt+= "<p>浏览器名称: " + navigator.appName + "</p>";
txt+= "<p>浏览器版本: " + navigator.appVersion + "</p>";
txt+= "<p>启用Cookies: " + navigator.cookieEnabled + "</p>";
txt+= "<p>硬件平台: " + navigator.platform + "</p>";
txt+= "<p>用户代理: " + navigator.userAgent + "</p>";
txt+= "<p>用户代理语言: " + navigator.language + "</p>";
document.getElementById("example").innerHTML=txt;
</script>

</body>
</html>

二、Navigator对象c++代码实现如下：

1）、Navigator接口定义third_party\blink\renderer\core\frame\navigator.idl


// https://html.spec.whatwg.org/C/#the-navigator-object

[
    Exposed=Window
] interface Navigator {
    // objects implementing this interface also implement the interfaces given below

    // TODO(foolip): vendorSub should be on NavigatorID.
    [HighEntropy=Direct, MeasureAs=NavigatorVendorSub] readonly attribute DOMString vendorSub;

    // TODO(foolip): productSub and vendor are not yet in the spec:
    // https://www.w3.org/Bugs/Public/show_bug.cgi?id=27954
    [HighEntropy=Direct, MeasureAs=NavigatorProductSub] readonly attribute DOMString productSub;
    // https://www.w3.org/Bugs/Public/show_bug.cgi?id=27786
    [HighEntropy=Direct, MeasureAs=NavigatorVendor] readonly attribute DOMString vendor;
};

Navigator includes NavigatorConcurrentHardware;
Navigator includes NavigatorCookies;
Navigator includes NavigatorDeviceMemory;
Navigator includes NavigatorID;
Navigator includes NavigatorLanguage;
Navigator includes NavigatorOnLine;
Navigator includes NavigatorAutomationInformation;
Navigator includes NavigatorUA;

1.1）、third_party\blink\renderer\core\frame\navigator_id.idl



// https://html.spec.whatwg.org/C/#client-identification

interface mixin NavigatorID {
    readonly attribute DOMString appCodeName; // constant "Mozilla"
    readonly attribute DOMString appName; // constant "Netscape"
    [HighEntropy=Direct, MeasureAs=NavigatorAppVersion] readonly attribute DOMString appVersion;
    [HighEntropy=Direct, MeasureAs=NavigatorPlatform] readonly attribute DOMString platform;
    readonly attribute DOMString product; // constant "Gecko"
    // https://www.w3.org/Bugs/Public/show_bug.cgi?id=22555
    // boolean taintEnabled(); // constant false
    [HighEntropy=Direct, MeasureAs=NavigatorUserAgent] readonly attribute DOMString userAgent;
};

2）、Navigator接口c++实现文件：

2.1）、third_party\blink\renderer\core\frame\navigator.h

third_party\blink\renderer\core\frame\navigator.cc


#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_NAVIGATOR_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_NAVIGATOR_H_

#include "third_party/blink/public/common/user_agent/user_agent_metadata.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/execution_context/navigator_base.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/supplementable.h"
#include "third_party/blink/renderer/platform/wtf/forward.h"

namespace blink {

class CORE_EXPORT Navigator final : public NavigatorBase,
                                    public Supplementable<Navigator> {
  DEFINE_WRAPPERTYPEINFO();

 public:
  explicit Navigator(ExecutionContext*);

  // NavigatorCookies
  bool cookieEnabled() const;

  bool webdriver() const;

  String productSub() const;
  String vendor() const;
  String vendorSub() const;

  String platform() const override;

  String GetAcceptLanguages() override;
  void SetUserAgentMetadataForTesting(UserAgentMetadata);

  void Trace(Visitor*) const override;

 private:
  UserAgentMetadata metadata_;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_NAVIGATOR_H_

2.2）、

third_party\blink\renderer\core\frame\navigator_id.h

third_party\blink\renderer\core\frame\navigator_id.cc


#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_NAVIGATOR_ID_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_NAVIGATOR_ID_H_

#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"

namespace blink {

class CORE_EXPORT NavigatorID {
 public:
  String appCodeName();
  String appName();
  String appVersion();
  virtual String platform() const;
  String product();
  virtual String userAgent() const = 0;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_NAVIGATOR_ID_H_

3)、v8_navigator接口注册实现文件：

out\Debug\gen\third_party\blink\renderer\bindings\modules\v8\v8_navigator.cc

out\Debug\gen\third_party\blink\renderer\bindings\modules\v8\v8_navigator.h

摘取其中navigator注册以及回调函数定义：

v8::Local<v8::FunctionTemplate> interface_function_template = interface_template.As<v8::FunctionTemplate>();
v8::Local<v8::Signature> signature = v8::Signature::New(isolate, interface_function_template);
{
  static const IDLMemberInstaller::AttributeConfig kAttributeTable[] = {
{"vendorSub", VendorSubAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"productSub", ProductSubAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"vendor", VendorAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"maxTouchPoints", MaxTouchPointsAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"scheduling", SchedulingAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"userActivation", UserActivationAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"doNotTrack", DoNotTrackAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"geolocation", GeolocationAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"connection", ConnectionAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"plugins", PluginsAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"mimeTypes", MimeTypesAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"pdfViewerEnabled", PdfViewerEnabledAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"webkitTemporaryStorage", WebkitTemporaryStorageAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"webkitPersistentStorage", WebkitPersistentStorageAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"hardwareConcurrency", HardwareConcurrencyAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"cookieEnabled", CookieEnabledAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"appCodeName", AppCodeNameAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"appName", AppNameAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"appVersion", AppVersionAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"platform", PlatformAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"product", ProductAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"userAgent", UserAgentAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"language", LanguageAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"languages", LanguagesAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"onLine", OnLineAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
{"webdriver", WebdriverAttributeGetCallback, nullptr, unsigned(v8::None), unsigned(IDLMemberInstaller::FlagLocation::kPrototype), unsigned(IDLMemberInstaller::FlagWorld::kAllWorlds), unsigned(IDLMemberInstaller::FlagReceiverCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(IDLMemberInstaller::FlagCrossOriginCheck::kCheck), unsigned(v8::SideEffectType::kHasNoSideEffect), unsigned(V8PrivateProperty::CachedAccessor::kNone)},
};
IDLMemberInstaller::InstallAttributes(isolate, world, instance_template, prototype_template, interface_template, signature, kAttributeTable);
}

里面其他接口定义，可以自行根据属性值搜索idl文件。