feat(fields): read/set all the fields from the given struct

fields/any.go

@@ -0,0 +1,23 @@
+// Copyright (c) 2023–present Bartłomiej Krukowski
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is furnished
+// to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package fields
+
+type any = interface{} //nolint

fields/any_test.go

@@ -0,0 +1,23 @@
+// Copyright (c) 2023–present Bartłomiej Krukowski
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is furnished
+// to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package fields_test
+
+type any = interface{} //nolint

fields/examples_test.go

@@ -0,0 +1,270 @@
+// Copyright (c) 2023–present Bartłomiej Krukowski
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is furnished
+// to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package fields_test
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/davecgh/go-spew/spew"
+	"github.com/gontainer/reflectpro/copier"
+	"github.com/gontainer/reflectpro/fields"
+)
+
+type Exercise struct {
+	Name string
+}
+
+type TrainingPlanMeta struct {
+	Name string
+}
+
+type TrainingPlan struct {
+	TrainingPlanMeta
+
+	Monday  Exercise
+	Tuesday Exercise
+}
+
+func ExampleIterate_set() {
+	p := TrainingPlan{}
+
+	_ = fields.Iterate(
+		&p,
+		fields.Setter(func(path fields.Path, _ any) (_ any, set bool) {
+			switch {
+			case path.EqualNames("TrainingPlanMeta", "Name"):
+				return "My training plan", true
+			case path.EqualNames("Monday", "Name"):
+				return "pushups", true
+			case path.EqualNames("Tuesday", "name"):
+				return "pullups", true
+			}
+
+			return nil, false
+		}),
+		fields.Recursive(true),
+	)
+
+	spew.Dump(p)
+
+	// Output:
+	// (fields_test.TrainingPlan) {
+	//  TrainingPlanMeta: (fields_test.TrainingPlanMeta) {
+	//   Name: (string) (len=16) "My training plan"
+	//  },
+	//  Monday: (fields_test.Exercise) {
+	//   Name: (string) (len=7) "pushups"
+	//  },
+	//  Tuesday: (fields_test.Exercise) {
+	//   Name: (string) ""
+	//  }
+	// }
+}
+
+type Phone struct {
+	os string
+}
+
+func ExampleIterate_setUnexported() {
+	p := Phone{}
+	_ = fields.Iterate(
+		&p,
+		fields.Setter(func(path fields.Path, _ any) (_ any, set bool) {
+			if path.EqualNames("os") {
+				return "Android", true
+			}
+
+			return nil, false
+		}),
+	)
+
+	fmt.Println(p.os)
+
+	// Output:
+	// Android
+}
+
+type MyCache struct {
+	TTL time.Duration
+}
+
+type MyConfig struct {
+	MyCache *MyCache
+}
+
+func ExamplePrefillNilStructs() {
+	cfg := MyConfig{}
+
+	/*
+		`cfg.MyCache` equals nil, but the line `fields.PrefillNilStructs(true)` instructs the library
+		to inject a pointer to the zero-value automatically, so we don't need to execute the following line manually:
+
+		cfg.MyCache = &MyCache{}
+	*/
+
+	_ = fields.Iterate(
+		&cfg,
+		fields.Setter(func(path fields.Path, _ any) (_ any, set bool) {
+			if path.EqualNames("MyCache", "TTL") {
+				return time.Minute, true
+			}
+
+			return nil, false
+		}),
+		fields.PrefillNilStructs(true),
+		fields.Recursive(true),
+	)
+
+	fmt.Println(cfg.MyCache.TTL)
+
+	// Output:
+	// 1m0s
+}
+
+type CTO struct {
+	Salary int
+}
+
+type Company struct {
+	CTO CTO
+}
+
+func ExampleIterate_get() {
+	c := Company{
+		CTO: CTO{
+			Salary: 1000000,
+		},
+	}
+
+	var salary int
+
+	_ = fields.Iterate(
+		c,
+		fields.Getter(func(p fields.Path, value any) {
+			if p.EqualNames("CTO", "Salary") {
+				_ = copier.Copy(value, &salary, false)
+			}
+		}),
+		fields.Recursive(true),
+	)
+
+	fmt.Println(salary)
+
+	// Output:
+	// 1000000
+}
+
+func ExampleConvertToPointers() {
+	var cfg struct {
+		TTL *time.Duration // expect a pointer
+	}
+
+	_ = fields.Iterate(
+		&cfg,
+		fields.Setter(func(path fields.Path, _ any) (_ any, set bool) {
+			if path.EqualNames("TTL") {
+				return time.Minute, true // return a value
+			}
+
+			return nil, false
+		}),
+		fields.ConvertToPointers(true), // this line will instruct the library to convert values to pointers
+	)
+
+	fmt.Println(*cfg.TTL)
+
+	// Output:
+	// 1m0s
+}
+
+func ExampleReadJSON() {
+	var person struct {
+		Firstname string `json:"firstname"`
+		Lastname  string `json:"lastname"`
+		Age       uint   `json:"age"`
+		Bio       string `json:"-"`
+	}
+
+	// read data from JSON...
+	js := `
+{
+	"firstname": "Jane",
+	"lastname": "Doe",
+	"age": 30,
+	"bio": "bio..."
+}`
+	var data map[string]any
+	_ = json.Unmarshal([]byte(js), &data)
+
+	// populate the data from JSON to the `person` variable,
+	// use struct tags, to determine the correct relations
+	_ = fields.Iterate(
+		&person,
+		fields.Setter(func(p fields.Path, _ any) (_ any, set bool) {
+			tag, ok := p[len(p)-1].Tag.Lookup("json")
+			if !ok {
+				return nil, false
+			}
+
+			name := strings.Split(tag, ",")[0]
+			if name == "-" {
+				return nil, false
+			}
+
+			if fromJSON, ok := data[name]; ok {
+				return fromJSON, true
+			}
+
+			return nil, false
+		}),
+		fields.ConvertTypes(true),
+	)
+
+	fmt.Printf("%+v\n", person)
+
+	// Output:
+	// {Firstname:Jane Lastname:Doe Age:30 Bio:}
+}
+
+func ExampleIterate_blank() {
+	var data struct {
+		_ int // fields.Iterate can access blank identifier
+	}
+
+	fmt.Println(data)
+
+	_ = fields.Iterate(&data, fields.Setter(func(path fields.Path, value any) (_ any, set bool) {
+		if path.EqualNames("_") {
+			return 10, true
+		}
+
+		return nil, false
+	}))
+
+	fmt.Println(data)
+
+	// Output:
+	// {0}
+	// {10}
+}