/
io.go
84 lines (74 loc) · 1.87 KB
/
io.go
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/*-
* Copyright 2019 Square Inc.
*
* 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 main
import (
"fmt"
"io"
"os"
)
// Read input from file or stdin
func readInput(path string) ([]byte, error) {
var bytes []byte
var err error
if path != "" {
bytes, err = os.ReadFile(path)
} else {
bytes, err = io.ReadAll(os.Stdin)
}
if err != nil {
return nil, fmt.Errorf("unable to read input: %w", err)
}
return bytes, nil
}
// Write output to file or stdin
func writeOutput(path string, data []byte) error {
var err error
if path != "" {
err = os.WriteFile(path, data, 0644)
} else {
_, err = os.Stdout.Write(data)
}
if err != nil {
return fmt.Errorf("unable to write output: %w", err)
}
return nil
}
// Byte contents of key file
func keyBytes() ([]byte, error) {
if *keyFile == "" {
return nil, fmt.Errorf("no key file provided. See -h for usage")
}
keyBytes, err := os.ReadFile(*keyFile)
if err != nil {
return nil, fmt.Errorf("unable to read key file: %w", err)
}
return keyBytes, nil
}
// Write new file to current dir
func writeNewFile(filename string, data []byte, perm os.FileMode) error {
f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm)
if err != nil {
return err
}
n, err := f.Write(data)
if err == nil && n < len(data) {
err = io.ErrShortWrite
}
if err1 := f.Close(); err == nil {
err = err1
}
return err
}