os: remove document duplication in error predicate functions

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5783092

src/pkg/os/error.go

@@ -42,3 +42,21 @@ func NewSyscallError(syscall string, err error) error {
 	}
 	return &SyscallError{syscall, err}
 }
+
+// IsExist returns whether the error is known to report that a file already exists.
+// It is satisfied by ErrExist as well as some syscall errors.
+func IsExist(err error) bool {
+	return isExist(err)
+}
+
+// IsNotExist returns whether the error is known to report that a file does not exist.
+// It is satisfied by ErrNotExist as well as some syscall errors.
+func IsNotExist(err error) bool {
+	return isNotExist(err)
+}
+
+// IsPermission returns whether the error is known to report that permission is denied.
+// It is satisfied by ErrPermission as well as some syscall errors.
+func IsPermission(err error) bool {
+	return isPermission(err)
+}

src/pkg/os/error_plan9.go

@@ -4,24 +4,21 @@
 
 package os
 
-// IsExist returns whether the error is known to report that a file already exists.
-func IsExist(err error) bool {
+func isExist(err error) bool {
 	if pe, ok := err.(*PathError); ok {
 		err = pe.Err
 	}
 	return contains(err.Error(), " exists")
 }
 
-// IsNotExist returns whether the error is known to report that a file does not exist.
-func IsNotExist(err error) bool {
+func isNotExist(err error) bool {
 	if pe, ok := err.(*PathError); ok {
 		err = pe.Err
 	}
 	return contains(err.Error(), "does not exist")
 }
 
-// IsPermission returns whether the error is known to report that permission is denied.
-func IsPermission(err error) bool {
+func isPermission(err error) bool {
 	if pe, ok := err.(*PathError); ok {
 		err = pe.Err
 	}

src/pkg/os/error_posix.go

@@ -8,27 +8,21 @@ package os
 
 import "syscall"
 
-// IsExist returns whether the error is known to report that a file already exists.
-// It is satisfied by ErrExist as well as some syscall errors.
-func IsExist(err error) bool {
+func isExist(err error) bool {
 	if pe, ok := err.(*PathError); ok {
 		err = pe.Err
 	}
 	return err == syscall.EEXIST || err == ErrExist
 }
 
-// IsNotExist returns whether the error is known to report that a file does not exist.
-// It is satisfied by ErrNotExist as well as some syscall errors.
-func IsNotExist(err error) bool {
+func isNotExist(err error) bool {
 	if pe, ok := err.(*PathError); ok {
 		err = pe.Err
 	}
 	return err == syscall.ENOENT || err == ErrNotExist
 }
 
-// IsPermission returns whether the error is known to report that permission is denied.
-// It is satisfied by ErrPermission as well as some syscall errors.
-func IsPermission(err error) bool {
+func isPermission(err error) bool {
 	if pe, ok := err.(*PathError); ok {
 		err = pe.Err
 	}

src/pkg/os/error_windows.go

@@ -6,9 +6,7 @@ package os
 
 import "syscall"
 
-// IsExist returns whether the error is known to report that a file already exists.
-// It is satisfied by ErrExist as well as some syscall errors.
-func IsExist(err error) bool {
+func isExist(err error) bool {
 	if pe, ok := err.(*PathError); ok {
 		err = pe.Err
 	}
@@ -16,18 +14,14 @@ func IsExist(err error) bool {
 		err == syscall.ERROR_FILE_EXISTS || err == ErrExist
 }
 
-// IsNotExist returns whether the error is known to report that a file does not exist.
-// It is satisfied by ErrNotExist as well as some syscall errors.
-func IsNotExist(err error) bool {
+func isNotExist(err error) bool {
 	if pe, ok := err.(*PathError); ok {
 		err = pe.Err
 	}
 	return err == syscall.ENOENT || err == ErrNotExist
 }
 
-// IsPermission returns whether the error is known to report that permission is denied.
-// It is satisfied by ErrPermission as well as some syscall errors.
-func IsPermission(err error) bool {
+func isPermission(err error) bool {
 	if pe, ok := err.(*PathError); ok {
 		err = pe.Err
 	}