vendor: vendor fscrypt integration dependencies

Signed-off-by: Marcel Lauhoff <marcel.lauhoff@suse.com>

vendor/github.com/google/fscrypt/util/errors.go

@@ -0,0 +1,135 @@
+/*
+ * errors.go - Custom errors and error functions used by fscrypt
+ *
+ * Copyright 2017 Google Inc.
+ * Author: Joe Richey (joerichey@google.com)
+ *
+ * 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 util
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+
+	"github.com/pkg/errors"
+)
+
+// ErrReader wraps an io.Reader, passing along calls to Read() until a read
+// fails. Then, the error is stored, and all subsequent calls to Read() do
+// nothing. This allows you to write code which has many subsequent reads and
+// do all of the error checking at the end. For example:
+//
+//	r := NewErrReader(reader)
+//	r.Read(foo)
+//	r.Read(bar)
+//	r.Read(baz)
+//	if r.Err() != nil {
+//		// Handle error
+//	}
+//
+// Taken from https://blog.golang.org/errors-are-values by Rob Pike.
+type ErrReader struct {
+	r   io.Reader
+	err error
+}
+
+// NewErrReader creates an ErrReader which wraps the provided reader.
+func NewErrReader(reader io.Reader) *ErrReader {
+	return &ErrReader{r: reader, err: nil}
+}
+
+// Read runs ReadFull on the wrapped reader if no errors have occurred.
+// Otherwise, the previous error is just returned and no reads are attempted.
+func (e *ErrReader) Read(p []byte) (n int, err error) {
+	if e.err == nil {
+		n, e.err = io.ReadFull(e.r, p)
+	}
+	return n, e.err
+}
+
+// Err returns the first encountered err (or nil if no errors occurred).
+func (e *ErrReader) Err() error {
+	return e.err
+}
+
+// ErrWriter works exactly like ErrReader, except with io.Writer.
+type ErrWriter struct {
+	w   io.Writer
+	err error
+}
+
+// NewErrWriter creates an ErrWriter which wraps the provided writer.
+func NewErrWriter(writer io.Writer) *ErrWriter {
+	return &ErrWriter{w: writer, err: nil}
+}
+
+// Write runs the wrapped writer's Write if no errors have occurred. Otherwise,
+// the previous error is just returned and no writes are attempted.
+func (e *ErrWriter) Write(p []byte) (n int, err error) {
+	if e.err == nil {
+		n, e.err = e.w.Write(p)
+	}
+	return n, e.err
+}
+
+// Err returns the first encountered err (or nil if no errors occurred).
+func (e *ErrWriter) Err() error {
+	return e.err
+}
+
+// CheckValidLength returns an invalid length error if expected != actual
+func CheckValidLength(expected, actual int) error {
+	if expected == actual {
+		return nil
+	}
+	return fmt.Errorf("expected length of %d, got %d", expected, actual)
+}
+
+// SystemError is an error that should indicate something has gone wrong in the
+// underlying system (syscall failure, bad ioctl, etc...).
+type SystemError string
+
+func (s SystemError) Error() string {
+	return "system error: " + string(s)
+}
+
+// NeverError panics if a non-nil error is passed in. It should be used to check
+// for logic errors, not to handle recoverable errors.
+func NeverError(err error) {
+	if err != nil {
+		log.Panicf("NeverError() check failed: %v", err)
+	}
+}
+
+var (
+	// testEnvVarName is the name of an environment variable that should be
+	// set to an empty mountpoint. This is only used for integration tests.
+	// If not set, integration tests are skipped.
+	testEnvVarName = "TEST_FILESYSTEM_ROOT"
+	// ErrSkipIntegration indicates integration tests shouldn't be run.
+	ErrSkipIntegration = errors.New("skipping integration test")
+)
+
+// TestRoot returns a the root of a filesystem specified by testEnvVarName. This
+// function is only used for integration tests.
+func TestRoot() (string, error) {
+	path := os.Getenv(testEnvVarName)
+	if path == "" {
+		return "", ErrSkipIntegration
+	}
+	return path, nil
+}