Merge pull request #933 from devlights/add-cmdexec-ospipe

Author: devlights

examples/basic/cmdexec/examples.go

@@ -22,4 +22,5 @@ func (r *register) Regist(m mapping.ExampleMapping) {
 	m["cmdexec_env"] = WithEnv
 	m["cmdexec_dir"] = WithDir
 	m["cmdexec_slice"] = WithSlice
+	m["cmdexec_ospipe"] = OsPipe
 }

examples/basic/cmdexec/ospipe.go

@@ -0,0 +1,68 @@
+package cmdexec
+
+import (
+	"bufio"
+	"log"
+	"os"
+	"os/exec"
+)
+
+// OsPipe は、(*Cmd).Stdout に os.Pipe の io.Writer を接続して処理するサンプルです.
+//
+// # REFERENCES
+//   - https://pkg.go.dev/os@go1.24.4#Pipe
+func OsPipe() error {
+	var (
+		pr  *os.File
+		pw  *os.File
+		err error
+	)
+	pr, pw, err = os.Pipe()
+	if err != nil {
+		return err
+	}
+	defer pr.Close()
+
+	var (
+		name = "git"
+		args = []string{"--no-pager", "log", "-m", "-r", "--name-only", "--pretty=raw", "-z"}
+		cmd  = exec.Command(name, args...)
+	)
+	cmd.Stdout = pw
+	if err = cmd.Start(); err != nil {
+		pw.Close()
+		return err
+	}
+
+	// 終了待機
+	var (
+		done = make(chan error, 1)
+	)
+	go func() {
+		defer pw.Close()
+		done <- cmd.Wait()
+	}()
+
+	const (
+		MaxTokenSize = 1024 * 1024
+	)
+	var (
+		scanner = bufio.NewScanner(pr)
+		buf     = make([]byte, MaxTokenSize)
+	)
+	scanner.Buffer(buf, MaxTokenSize)
+
+	for scanner.Scan() {
+		log.Println(scanner.Text())
+	}
+
+	if err = scanner.Err(); err != nil {
+		return err
+	}
+
+	if err = <-done; err != nil {
+		return err
+	}
+
+	return nil
+}