Add DebugMutator

internal/chezmoi/debugmutator.go

@@ -0,0 +1,118 @@
+package chezmoi
+
+import (
+	"log"
+	"os"
+	"os/exec"
+	"time"
+)
+
+// A DebugMutator wraps a Mutator and logs all of the actions it executes.
+type DebugMutator struct {
+	m Mutator
+}
+
+// NewDebugMutator returns a new DebugMutator.
+func NewDebugMutator(m Mutator) *DebugMutator {
+	return &DebugMutator{
+		m: m,
+	}
+}
+
+// Chmod implements Mutator.Chmod.
+func (m *DebugMutator) Chmod(name string, mode os.FileMode) error {
+	return Debugf("Chmod(%q, 0%o)", []interface{}{name, mode}, func() error {
+		return m.m.Chmod(name, mode)
+	})
+}
+
+// IdempotentCmdOutput implements Mutator.IdempotentCmdOutput.
+func (m *DebugMutator) IdempotentCmdOutput(cmd *exec.Cmd) ([]byte, error) {
+	var output []byte
+	err := Debugf("IdempotentCmdOutput(%v)", []interface{}{cmd}, func() error {
+		var err error
+		output, err = m.m.IdempotentCmdOutput(cmd)
+		return err
+	})
+	return output, err
+}
+
+// Mkdir implements Mutator.Mkdir.
+func (m *DebugMutator) Mkdir(name string, perm os.FileMode) error {
+	return Debugf("Mkdir(%q, 0%o)", []interface{}{name, perm}, func() error {
+		return m.m.Mkdir(name, perm)
+	})
+}
+
+// RemoveAll implements Mutator.RemoveAll.
+func (m *DebugMutator) RemoveAll(name string) error {
+	return Debugf("RemoveAll(%q)", []interface{}{name}, func() error {
+		return m.m.RemoveAll(name)
+	})
+}
+
+// Rename implements Mutator.Rename.
+func (m *DebugMutator) Rename(oldpath, newpath string) error {
+	return Debugf("Rename(%q, %q)", []interface{}{oldpath, newpath}, func() error {
+		return m.Rename(oldpath, newpath)
+	})
+}
+
+// RunCmd implements Mutator.RunCmd.
+func (m *DebugMutator) RunCmd(cmd *exec.Cmd) error {
+	return Debugf("Run(%v)", []interface{}{cmd}, func() error {
+		return m.m.RunCmd(cmd)
+	})
+}
+
+// Stat implements Mutator.Stat.
+func (m *DebugMutator) Stat(name string) (os.FileInfo, error) {
+	var fi os.FileInfo
+	var err error
+	Debugf("Stat(%q)", []interface{}{name}, func() error {
+		fi, err = m.m.Stat(name)
+		return err
+	})
+	return fi, err
+}
+
+// WriteFile implements Mutator.WriteFile.
+func (m *DebugMutator) WriteFile(name string, data []byte, perm os.FileMode, currData []byte) error {
+	return Debugf("WriteFile(%q, _, 0%o, _)", []interface{}{name, perm}, func() error {
+		return m.m.WriteFile(name, data, perm, currData)
+	})
+}
+
+// WriteSymlink implements Mutator.WriteSymlink.
+func (m *DebugMutator) WriteSymlink(oldname, newname string) error {
+	return Debugf("WriteSymlink(%q, %q)", []interface{}{oldname, newname}, func() error {
+		return m.m.WriteSymlink(oldname, newname)
+	})
+}
+
+// Debugf logs debugging information about calling f.
+func Debugf(format string, args []interface{}, f func() error) error {
+	errChan := make(chan error)
+	start := time.Now()
+	go func(errChan chan<- error) {
+		errChan <- f()
+	}(errChan)
+	select {
+	case err := <-errChan:
+		if err == nil {
+			log.Printf(format+" (%s)", append(args, time.Since(start))...)
+		} else {
+			log.Printf(format+" == %v (%s)", append(args, err, time.Since(start)))
+		}
+		return err
+	case <-time.After(1 * time.Second):
+		log.Printf(format, args...)
+		err := <-errChan
+		if err == nil {
+			log.Printf(format+" (%s)", append(args, time.Since(start))...)
+		} else {
+			log.Printf(format+" == %v (%s)", append(args, err, time.Since(start)))
+		}
+		return err
+	}
+}