Changes between Version 2 and Version 3 of AnalyzingBuildPerformance

Timestamp:

Oct 7, 2021 12:24:32 PM (3 years ago)

Author:

jer.noble@apple.com

Comment:

--

AnalyzingBuildPerformance

@@ -56 +56 @@
 C++ class members must be fully defined, so e.g. consider using `UniqueRef<MyClass>`, and forward-declaring `MyClass`, instead of including `MyClass.h`.
 
-C++ function parameters and return values do not need to be fully defined, and can be forward-declared. So e.g. if `MyClass` function parameter or return value, consider forward-declaring `MyClass`, instead of including `MyClass.h`.
+C++ function parameters and return values do not need to be fully defined, and can be forward-declared. So e.g. if a method in your class uses `MyClass` as function parameter or return value, consider forward-declaring `MyClass`, instead of including `MyClass.h`.
 
 C++ virtual functions are rarely able to be inlined, even if decorated with `inline`, so avoid inline definitions of virtual functions. So e.g. if defining a virtual base class method that returns a `Ref<MyClass>`, put the default implementation inside the class implementation file.
+
+Bad:
+{{{
+#!c++
+// MyClass.h
+#include "YourClass.h"
+class MyClass {
+public:
+    void passByValue(YourClass);
+    void passByReference(const YourClass&);
+    YourClass getByValue();
+    virtual std::unique_ptr<YourClass> createUnique() { return nullptr; }
+};
+}}}
+
+Good:
+{{{
+#!c++
+// MyClass.h
+class YourClass;
+
+class MyClass {
+public:
+    void passByValue(YourClass);
+    void passByReference(const YourClass&);
+    YourClass getByValue();
+    virtual std::unique_ptr<YourClass> createUnique();
+};
+
+// MyClass.cpp
+#include "YourClass.h"
+std::unique_ptr<YourClass> MyClass::createUnique()
+{
+    return nullptr;
+}
+}}}
+
 
 ==== Avoid class-scoped enums ====
@@ -115 +152 @@
 class MyClass {
 public:
-    YourClass& yourClassGetFoo() { return YourClass::foo(); }
+    YourClass getFoo() { return YourClass::foo(); }
 };
 }}}
@@ -123 +160 @@
 #!c++
 // MyClass.h
+class YourClass;
+
 class MyClass {
 public:
-    inline YourClass& yourClassGetFoo();
+    inline YourClass getFoo();
 };
 
 // MyClassInlines.h
-inline YourClass& MyClass::yourClassGetFoo() { return YourClass::foo(); }
+#include "YourClass.h"
+inline YourClass& MyClass::getFoo() { return YourClass::foo(); }
 }}}