Add pathutil

internal/util/pathutil/pathutil.go

@@ -0,0 +1,82 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// This package contains some path-relevant utilities.
+package pathutil
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// Rel, like path.Rel, converts a path into a relative path to directory with the knowledge of cwd.
+// Cwd, which should be an absolute path, will be used if either base or path is a relative paths.
+func Rel(base string, path string, cwd string) (relativePath string, err error) {
+	relativePath, err = filepath.Rel(base, path)
+
+	if err != nil {
+		// Rel returns an error if CWD is necessary to compute it. Here is a fix.
+		if !filepath.IsAbs(path) {
+			path = filepath.Join(cwd, path)
+		}
+
+		if !filepath.IsAbs(base) {
+			base = filepath.Join(cwd, base)
+		}
+
+		relativePath, err = filepath.Rel(base, path)
+	}
+
+	return
+}
+
+// Exists returns true only if path exists and is accessible.
+func Exists(path string) bool {
+	_, err := os.Stat(path)
+
+	return !os.IsNotExist(err)
+}
+
+// IsInsideDir checks if path is within directory.
+// Both path and directory have to be absolute paths.
+func IsInsideDir(path string, directory string) (isInside bool, err error) {
+	if !filepath.IsAbs(path) {
+		err = fmt.Errorf(
+			"argument `path` (%s) is not an absolute path",
+			path,
+		)
+		return
+	}
+	if !filepath.IsAbs(directory) {
+		err = fmt.Errorf(
+			"argument `directory` (%s) is not an absolute path",
+			directory,
+		)
+		return
+	}
+
+	separator := string(os.PathSeparator)
+	// Trim the ending separator if any
+	directory = strings.TrimRight(directory, separator)
+	directoryWithSeparator := fmt.Sprintf("%s%s", directory, separator)
+
+	isInside = path == directory || strings.HasPrefix(
+		path,
+		directoryWithSeparator,
+	)
+
+	return
+}

internal/util/pathutil/pathutil_test.go

@@ -0,0 +1,105 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pathutil
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"testing"
+
+	"github.com/GoogleContainerTools/kpt/internal/testutil"
+	"gotest.tools/assert"
+)
+
+func TestRel(t *testing.T) {
+	base := path.Join(os.TempDir(), "kpt-path-test")
+	cwd := base
+
+	actual, err := Rel(base, "resources", cwd)
+	expected := "resources"
+	testutil.AssertNoError(t, err)
+	assert.Equal(t, expected, actual)
+
+	actual, err = Rel(base, path.Join(base, "resources"), cwd)
+	expected = "resources"
+	testutil.AssertNoError(t, err)
+	assert.Equal(t, expected, actual)
+
+	actual, err = Rel(base, "./config", cwd)
+	expected = "config"
+	testutil.AssertNoError(t, err)
+	assert.Equal(t, expected, actual)
+
+	actual, err = Rel(base, "../some-dir", cwd)
+	expected = "../some-dir"
+	testutil.AssertNoError(t, err)
+	assert.Equal(t, expected, actual)
+
+	actual, err = Rel(base, os.TempDir(), cwd)
+	expected = ".."
+	testutil.AssertNoError(t, err)
+	assert.Equal(t, expected, actual)
+
+	actual, err = Rel(base, "kpt-path-test", os.TempDir())
+	expected = "."
+	testutil.AssertNoError(t, err)
+	assert.Equal(t, expected, actual)
+}
+
+func TestExists(t *testing.T) {
+	base, err := ioutil.TempDir("", "kpt-path-test")
+	testutil.AssertNoError(t, err)
+	defer os.RemoveAll(base)
+
+	assert.Equal(t, Exists(base), true)
+	assert.Equal(t, Exists(path.Join(base, "some-random-dir")), false)
+}
+
+func TestIsInsideDirectory(t *testing.T) {
+	base := path.Join(os.TempDir(), "kpt-path-test")
+	file := path.Join(base, "temp-file")
+	dirWithSamePrefix := fmt.Sprintf("%s-surfix", base)
+	baseWithSeparator := fmt.Sprintf(
+		"%s%s",
+		base,
+		string(os.PathSeparator),
+	)
+
+	_, err := IsInsideDir("resources", ".")
+	assert.Error(t, err, "argument `path` (resources) is not an absolute path")
+	_, err = IsInsideDir("/resources", ".")
+	assert.Error(t, err, "argument `directory` (.) is not an absolute path")
+
+	result, err := IsInsideDir(path.Join(base, "."), base)
+	assert.NilError(t, err)
+	assert.Equal(t, result, true)
+	result, err = IsInsideDir(path.Join(base, "."), baseWithSeparator)
+	assert.NilError(t, err)
+	assert.Equal(t, result, true)
+	result, err = IsInsideDir(file, base)
+	assert.NilError(t, err)
+	assert.Equal(t, result, true)
+	result, err = IsInsideDir(path.Join(base, file), baseWithSeparator)
+	assert.NilError(t, err)
+	assert.Equal(t, result, true)
+	result, err = IsInsideDir(path.Join(base, ".."), base)
+	assert.NilError(t, err)
+	assert.Equal(t, result, false)
+	result, err = IsInsideDir(dirWithSamePrefix, base)
+	assert.NilError(t, err)
+	assert.Equal(t, result, false)
+}