blob: 384484449eabf82a771b92036b5860c40167f4b6 [file] [log] [blame]
// Copyright 2019 CUE Authors
//
// 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 source contains utility functions that standardize reading source
// bytes across cue packages.
package source
import (
"bytes"
"fmt"
"io"
"io/ioutil"
)
// Read loads the source bytes for the given arguments. If src != nil,
// Read converts src to a []byte if possible; otherwise it returns an
// error. If src == nil, readSource returns the result of reading the file
// specified by filename.
//
func Read(filename string, src interface{}) ([]byte, error) {
if src != nil {
switch s := src.(type) {
case string:
return []byte(s), nil
case []byte:
return s, nil
case *bytes.Buffer:
// is io.Reader, but src is already available in []byte form
if s != nil {
return s.Bytes(), nil
}
case io.Reader:
var buf bytes.Buffer
if _, err := io.Copy(&buf, s); err != nil {
return nil, err
}
return buf.Bytes(), nil
}
return nil, fmt.Errorf("invalid source type %T", src)
}
return ioutil.ReadFile(filename)
}