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03-UnrealEngine/Gameplay/UObject/UnrealSpecifiers/Meta/UHT/ModuleRelativePath.md

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+# ModuleRelativePath
+
+- **功能描述：** 记录类型定义的的头文件路径，为其处于模块的内部相对路径。
+- **使用位置：** Any
+- **引擎模块：** UHT
+- **元数据类型：** string="abc"
+- **常用程度：** 0
+
+记录当前元类型定义的的头文件路径，为相对模块的相对路径。
+
+对于开发者来说一般不用管，但是引擎编辑器会用它来定位某个类型是在哪个.h里定义的，从而在你双击类型的时候，可以为你在VS里打开相应的头文件。具体的逻辑可以去FSourceCodeNavigation里查看。
+
+和IncludePath的区别是，ModuleRelativePath 在各种类型信息上都有，而IncludePath只用于UCLASS上。另外ModuleRelativePath 的值可以包含“Classes/Public/Internal/Private”这4个以开头，我们一般也确实会建议把.h.cpp划分到这4个文件夹里。而IncludeFilePath 的值就会去掉这个头。
+
+## 测试代码：
+
+```cpp
+UCLASS(BlueprintType)
+class INSIDER_API UMyProperty_Template :public UObject
+{
+	GENERATED_BODY()
+public:
+	UFUNCTION(BlueprintCallable)
+	int32 MyFunc(FString str){return 0;}
+	UPROPERTY(EditAnywhere, BlueprintReadWrite)
+	int32 MyProperty = 123;
+};
+```
+
+## 其元类型信息打印：
+
+可以发现ModuleRelativePath 在类，属性和函数上都有该信息。
+
+而IncludePath只有在UCLASS上才有。
+
+```cpp
+[class MyProperty_Template	Class->Struct->Field->Object	/Script/Insider.MyProperty_Template]
+(BlueprintType = true, IncludePath = Property/MyProperty_Template.h, ModuleRelativePath = Property/MyProperty_Template.h)
+	ObjectFlags:	RF_Public | RF_Standalone | RF_Transient 
+	Outer:	Package /Script/Insider
+	ClassHierarchy:	MyProperty_Template:Object
+	ClassFlags:	CLASS_MatchedSerializers | CLASS_Native | CLASS_RequiredAPI | CLASS_TokenStreamAssembled | CLASS_Intrinsic | CLASS_Constructed 
+	Size:	56
+	Within:	Object
+	ClassConfigName:	Engine
+{
+	(Category = MyProperty_Template, ModuleRelativePath = Property/MyProperty_Template.h)
+	48-[4] int32 MyProperty;
+		PropertyFlags:	CPF_Edit | CPF_BlueprintVisible | CPF_ZeroConstructor | CPF_IsPlainOldData | CPF_NoDestructor | CPF_HasGetValueTypeHash | CPF_NativeAccessSpecifierPublic 
+		ObjectFlags:	RF_Public | RF_MarkAsNative | RF_Transient 
+		Outer:	Class /Script/Insider.MyProperty_Template
+		Path:	IntProperty /Script/Insider.MyProperty_Template:MyProperty
+	[func MyFunc	Function->Struct->Field->Object	/Script/Insider.MyProperty_Template:MyFunc]
+	(ModuleRelativePath = Property/MyProperty_Template.h)
+		ObjectFlags:	RF_Public | RF_Transient 
+		Outer:	Class /Script/Insider.MyProperty_Template
+		FunctionFlags:	FUNC_Final | FUNC_Native | FUNC_Public | FUNC_BlueprintCallable 
+		NumParms:	2
+		ParmsSize:	20
+		ReturnValueOffset:	16
+		RPCId:	0
+		RPCResponseId:	0
+		public int32 MyFunc(FString str)final;
+	{
+		0-[16] FString str;
+			PropertyFlags:	CPF_Parm | CPF_ZeroConstructor | CPF_HasGetValueTypeHash | CPF_NativeAccessSpecifierPublic 
+			ObjectFlags:	RF_Public | RF_MarkAsNative | RF_Transient 
+			Outer:	Function /Script/Insider.MyProperty_Template:MyFunc
+			Path:	StrProperty /Script/Insider.MyProperty_Template:MyFunc:str
+		16-[4] int32 ReturnValue;
+			PropertyFlags:	CPF_Parm | CPF_OutParm | CPF_ZeroConstructor | CPF_ReturnParm | CPF_IsPlainOldData | CPF_NoDestructor | CPF_HasGetValueTypeHash | CPF_NativeAccessSpecifierPublic 
+			ObjectFlags:	RF_Public | RF_MarkAsNative | RF_Transient 
+			Outer:	Function /Script/Insider.MyProperty_Template:MyFunc
+			Path:	IntProperty /Script/Insider.MyProperty_Template:MyFunc:ReturnValue
+	};
+};
+
+```
+
+## 原理：
+
+在UHT分析的时候，自动的为类型加上头文件的路径信息。
+
+从源码逻辑可以看出，ModuleRelativePath 的值可以包含“Classes/Public/Internal/Private”这4个以开头，我们一般也确实会建议把.h.cpp划分到这4个文件夹里。而IncludeFilePath 的值就会去掉这个头。
+
+```cpp
+
+public enum UhtHeaderFileType
+{
+
+	/// <summary>
+	/// Classes folder
+	/// </summary>
+	Classes,
+
+	/// <summary>
+	/// Public folder
+	/// </summary>
+	Public,
+
+	/// <summary>
+	/// Internal folder
+	/// </summary>
+	Internal,
+
+	/// <summary>
+	/// Private folder
+	/// </summary>
+	Private,
+}
+
+public static void AddModuleRelativePathToMetaData(UhtMetaData metaData, UhtHeaderFile headerFile)
+{
+	metaData.Add(UhtNames.ModuleRelativePath, headerFile.ModuleRelativeFilePath);
+}
+
+//分析文件路径
+private void StepPrepareHeaders(UhtPackage package, IEnumerable<string> headerFiles, UhtHeaderFileType headerFileType)
+{
+	string typeDirectory = headerFileType.ToString() + '/';
+	
+	headerFile.ModuleRelativeFilePath = normalizedFullFilePath[stripLength..];
+	if (normalizedFullFilePath[stripLength..].StartsWith(typeDirectory, true, null))
+	{
+					stripLength += typeDirectory.Length;
+	}
+	headerFile.IncludeFilePath = normalizedFullFilePath[stripLength..];
+}	
+
+```