C++: Respond to review comments.

Author: MathiasVP

cpp/ql/src/semmle/code/cpp/exprs/Call.qll

@@ -300,6 +300,14 @@ class FunctionCall extends Call, @funbindexpr {
   }
 }
 
+/** A _user-defined_ unary `operator*` function. */
+class OverloadedPointerDereferenceFunction extends Function {
+  OverloadedPointerDereferenceFunction() {
+    this.hasName("operator*") and
+    this.getEffectiveNumberOfParameters() = 1
+  }
+}
+
 /**
  * An instance of a _user-defined_ unary `operator*` applied to its argument.
  * ```
@@ -309,8 +317,7 @@ class FunctionCall extends Call, @funbindexpr {
  */
 class OverloadedPointerDereferenceExpr extends FunctionCall {
   OverloadedPointerDereferenceExpr() {
-    getTarget().hasName("operator*") and
-    getTarget().getEffectiveNumberOfParameters() = 1
+    this.getTarget() instanceof OverloadedPointerDereferenceFunction
   }
 
   override string getAPrimaryQlClass() { result = "OverloadedPointerDereferenceExpr" }
@@ -350,53 +357,6 @@ class OverloadedPointerDereferenceExpr extends FunctionCall {
   }
 }
 
-/**
- * An instance of a call to a _user-defined_ `operator->`.
- * ```
- * struct T2 { T1 b; };
- * struct T3 { T2* operator->(); };
- * T3 a;
- * T1 x = a->b;
- * ```
- */
-class OverloadedArrowExpr extends FunctionCall {
-  OverloadedArrowExpr() { getTarget().hasName("operator->") }
-
-  override string getAPrimaryQlClass() { result = "OverloadedArrowExpr" }
-
-  /** Gets the expression this `operator->` applies to. */
-  Expr getExpr() { result = this.getQualifier() }
-
-  /** Gets the field accessed by this call to `operator->`, if any. */
-  FieldAccess getFieldAccess() { result.getQualifier() = this }
-
-  override predicate mayBeImpure() {
-    FunctionCall.super.mayBeImpure() and
-    (
-      this.getExpr().mayBeImpure()
-      or
-      not exists(Class declaring |
-        this.getTarget().getDeclaringType().isConstructedFrom*(declaring)
-      |
-        declaring.getNamespace() instanceof StdNamespace
-      )
-    )
-  }
-
-  override predicate mayBeGloballyImpure() {
-    FunctionCall.super.mayBeGloballyImpure() and
-    (
-      this.getExpr().mayBeGloballyImpure()
-      or
-      not exists(Class declaring |
-        this.getTarget().getDeclaringType().isConstructedFrom*(declaring)
-      |
-        declaring.getNamespace() instanceof StdNamespace
-      )
-    )
-  }
-}
-
 /**
  * An instance of a _user-defined_ binary `operator[]` applied to its arguments.
  * ```

cpp/ql/src/semmle/code/cpp/models/Models.qll

@@ -33,4 +33,3 @@ private import implementations.Recv
 private import implementations.Accept
 private import implementations.Poll
 private import implementations.Select
-private import implementations.PointerWrapper

cpp/ql/src/semmle/code/cpp/models/implementations/PointerWrapper.qll

@@ -1,10 +1,20 @@
 import semmle.code.cpp.models.interfaces.Taint
+import semmle.code.cpp.models.interfaces.PointerWrapper
 
 /**
  * The `std::shared_ptr` and `std::unique_ptr` template classes.
  */
-private class UniqueOrSharedPtr extends Class {
+private class UniqueOrSharedPtr extends Class, PointerWrapper {
   UniqueOrSharedPtr() { this.hasQualifiedName(["std", "bsl"], ["shared_ptr", "unique_ptr"]) }
+
+  override MemberFunction getADereferenceFunction() {
+    result.(OverloadedPointerDereferenceFunction).getDeclaringType() = this
+  }
+
+  override MemberFunction getAnUnwrapperFunction() {
+    result.getDeclaringType() = this and
+    result.hasName(["operator->", "get"])
+  }
 }
 
 /**

cpp/ql/src/semmle/code/cpp/models/implementations/SmartPointer.qll

@@ -0,0 +1,12 @@
+/** Provides classes for modeling pointer wrapper types and expressions. */
+
+private import cpp
+
+/** A class that wraps a pointer type. For example, `std::unique_ptr` and `std::shared_ptr`. */
+abstract class PointerWrapper extends Class {
+  /** Gets a member fucntion of this class that dereferences wrapped pointer, if any. */
+  abstract MemberFunction getADereferenceFunction();
+
+  /** Gets a member fucntion of this class that returns the wrapped pointer, if any. */
+  abstract MemberFunction getAnUnwrapperFunction();
+}