Adds support for patching value struct (#5)

* adds support for patching value struct

* add go versions to the matrix

Author: tonyredondo

.github/workflows/go.yml

@@ -5,7 +5,7 @@ jobs:
     name: Test
     strategy:
       matrix:
-        go_version: [1.12, 1.13]
+        go_version: [1.11, 1.12, 1.13, 1.14]
         os: [ubuntu-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     steps:

patcher.go

@@ -42,10 +42,11 @@ func PatchMethod(target, redirection interface{}) (*Patch, error) {
 	return patch, nil
 }
 func PatchInstanceMethodByName(target reflect.Type, methodName string, redirection interface{}) (*Patch, error) {
-	if target.Kind() == reflect.Struct {
+	method, ok := target.MethodByName(methodName)
+	if !ok && target.Kind() == reflect.Struct {
 		target = reflect.PtrTo(target)
+		method, ok = target.MethodByName(methodName)
 	}
-	method, ok := target.MethodByName(methodName)
 	if !ok {
 		return nil, errors.New(fmt.Sprintf("Method '%v' not found", methodName))
 	}

patcher_test.go

@@ -19,6 +19,11 @@ func (s *myStruct) Method() int {
 	return 1
 }
 
+//go:noinline
+func (s myStruct) ValueMethod() int {
+	return 1
+}
+
 func TestPatcher(t *testing.T) {
 	patch, err := PatchMethod(methodA, methodB)
 	if err != nil {
@@ -62,3 +67,29 @@ func TestInstancePatcher(t *testing.T) {
 		t.Fatal("The unpatch did not work")
 	}
 }
+
+func TestInstanceValuePatcher(t *testing.T) {
+	mStruct := myStruct{}
+
+	var patch *Patch
+	var err error
+	patch, err = PatchInstanceMethodByName(reflect.TypeOf(mStruct), "ValueMethod", func(m myStruct) int {
+		patch.Unpatch()
+		defer patch.Patch()
+		return 41 + m.Method()
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if mStruct.ValueMethod() != 42 {
+		t.Fatal("The patch did not work")
+	}
+	err = patch.Unpatch()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if mStruct.ValueMethod() != 1 {
+		t.Fatal("The unpatch did not work")
+	}
+}

patcher_unsupported.go

@@ -12,4 +12,4 @@ import (
 // Gets the jump function rewrite bytes
 func getJumpFuncBytes(to uintptr) ([]byte, error) {
 	return nil, errors.New(fmt.Sprintf("Unsupported architecture: %s", runtime.GOARCH))
-}
+}