3P updates

02-code-project-organization/1-variable-shadowing/main.go

@@ -64,6 +64,22 @@ func listing3() error {
 	return nil
 }
 
+func listing4() error {
+	var client *http.Client
+	var err error
+	if tracing {
+		client, err = createClientWithTracing()
+	} else {
+		client, err = createDefaultClient()
+	}
+	if err != nil {
+		return err
+	}
+
+	_ = client
+	return nil
+}
+
 var tracing bool
 
 func createClientWithTracing() (*http.Client, error) {

02-code-project-organization/3-init-functions/db/main.go

@@ -20,3 +20,14 @@ func init() {
 	}
 	db = d
 }
+
+func createClient(dataSourceName string) (*sql.DB, error) {
+	db, err := sql.Open("mysql", dataSourceName)
+	if err != nil {
+		return nil, err
+	}
+	if err = db.Ping(); err != nil {
+		return nil, err
+	}
+	return db, nil
+}

02-code-project-organization/5-interface-pollution/restricting-behavior/main.go

@@ -0,0 +1,35 @@
+package main
+
+type IntConfig struct {
+	value int
+}
+
+func (c *IntConfig) Get() int {
+	return c.value
+}
+
+func (c *IntConfig) Set(value int) {
+	c.value = value
+}
+
+type intConfigGetter interface {
+	Get() int
+}
+
+type Foo struct {
+	threshold intConfigGetter
+}
+
+func NewFoo(threshold intConfigGetter) Foo {
+	return Foo{threshold: threshold}
+}
+
+func (f Foo) Bar() {
+	threshold := f.threshold.Get()
+	_ = threshold
+}
+
+func main() {
+	foo := NewFoo(&IntConfig{value: 42})
+	foo.Bar()
+}

02-code-project-organization/6-interface-producer/client/client.go

@@ -0,0 +1,7 @@
+package client
+
+import "github.com/teivah/100-go-mistakes/02-code-project-organization/6-interface-producer/store"
+
+type customersGetter interface {
+	GetAllCustomers() ([]store.Customer, error)
+}

02-code-project-organization/6-interface-producer/store/store.go

@@ -0,0 +1,12 @@
+package store
+
+type Storer interface {
+	StoreCustomer(customer Customer) error
+	GetCustomer(id string) (Customer, error)
+	UpdateCustomer(customer Customer) error
+	GetAllCustomers() ([]Customer, error)
+	GetCustomersWithoutContract() ([]Customer, error)
+	GetCustomersWithNegativeBalance() ([]Customer, error)
+}
+
+type Customer struct{}

02-code-project-organization/9-generics/main.go

@@ -1,6 +1,9 @@
 package main
 
-import "fmt"
+import (
+	"fmt"
+	"sort"
+)
 
 func getKeys(m any) ([]any, error) {
 	switch t := m.(type) {
@@ -44,11 +47,22 @@ func (n *Node[T]) Add(next *Node[T]) {
 	n.next = next
 }
 
-type sliceFn[T any] struct {
-	s       []T
-	compare func(T, T) bool
+type SliceFn[T any] struct {
+	S       []T
+	Compare func(T, T) bool
 }
 
-func (s sliceFn[T]) Len() int           { return len(s.s) }
-func (s sliceFn[T]) Less(i, j int) bool { return s.compare(s.s[i], s.s[j]) }
-func (s sliceFn[T]) Swap(i, j int)      { s.s[i], s.s[j] = s.s[j], s.s[i] }
+func (s SliceFn[T]) Len() int           { return len(s.S) }
+func (s SliceFn[T]) Less(i, j int) bool { return s.Compare(s.S[i], s.S[j]) }
+func (s SliceFn[T]) Swap(i, j int)      { s.S[i], s.S[j] = s.S[j], s.S[i] }
+
+func main() {
+	s := SliceFn[int]{
+		S: []int{3, 2, 1},
+		Compare: func(a, b int) bool {
+			return a < b
+		},
+	}
+	sort.Sort(s)
+	fmt.Println(s.S)
+}

05-strings/39-string-concat/main.go

@@ -2,32 +2,32 @@ package main
 
 import "strings"
 
-func concat1(ids []string) string {
+func concat1(values []string) string {
 	s := ""
-	for _, id := range ids {
-		s += id
+	for _, value := range values {
+		s += value
 	}
 	return s
 }
 
-func concat2(ids []string) string {
+func concat2(values []string) string {
 	sb := strings.Builder{}
-	for _, id := range ids {
-		_, _ = sb.WriteString(id)
+	for _, value := range values {
+		_, _ = sb.WriteString(value)
 	}
 	return sb.String()
 }
 
-func concat3(ids []string) string {
+func concat3(values []string) string {
 	total := 0
-	for i := 0; i < len(ids); i++ {
-		total += len(ids[i])
+	for i := 0; i < len(values); i++ {
+		total += len(values[i])
 	}
 
 	sb := strings.Builder{}
 	sb.Grow(total)
-	for _, id := range ids {
-		_, _ = sb.WriteString(id)
+	for _, value := range values {
+		_, _ = sb.WriteString(value)
 	}
 	return sb.String()
 }

05-strings/41-substring-memory-leak/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"errors"
 	"fmt"
+	"strings"
 )
 
 func main() {
@@ -37,6 +38,16 @@ func (s store) handleLog2(log string) error {
 	return nil
 }
 
+func (s store) handleLog3(log string) error {
+	if len(log) < 36 {
+		return errors.New("log is not correctly formatted")
+	}
+	uuid := string(strings.Clone(log[:36]))
+	s.store(uuid)
+	// Do something
+	return nil
+}
+
 func (s store) store(uuid string) {
 	// ...
 }