Isolated content of pkg/loader

pkg/loader/fileloader.go

@@ -0,0 +1,81 @@
+/*
+Copyright 2018 The Kubernetes 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 loader
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"k8s.io/kubectl/pkg/kustomize/util/fs"
+)
+
+const currentDir = "."
+
+// Internal implementation of SchemeLoader interface.
+type fileLoader struct {
+	fs fs.FileSystem
+}
+
+// NewFileLoader returns a SchemeLoader to handle a file system.
+func NewFileLoader(fs fs.FileSystem) SchemeLoader {
+	return &fileLoader{fs: fs}
+}
+
+// Is the location calculated with the root and location params a full file path.
+func (l *fileLoader) IsScheme(root string, location string) bool {
+	fullFilePath, err := l.FullLocation(root, location)
+	if err != nil {
+		return false
+	}
+	return filepath.IsAbs(fullFilePath)
+}
+
+// If location is a full file path, then ignore root. If location is relative, then
+// join the root path with the location path. Either root or location can be empty,
+// but not both. Special case for ".": Expands to current working directory.
+// Example: "/home/seans/project", "subdir/bar" -> "/home/seans/project/subdir/bar".
+func (l *fileLoader) FullLocation(root string, location string) (string, error) {
+	// First, validate the parameters
+	if len(root) == 0 && len(location) == 0 {
+		return "", fmt.Errorf("Unable to calculate full location: root and location empty")
+	}
+	// Special case current directory, expanding to full file path.
+	if location == currentDir {
+		currentDir, err := os.Getwd()
+		if err != nil {
+			return "", err
+		}
+		location = currentDir
+	}
+	// Assume the location is a full file path. If not, then join root with location.
+	fullLocation := location
+	if !filepath.IsAbs(location) {
+		fullLocation = filepath.Join(root, location)
+	}
+	return fullLocation, nil
+}
+
+// Load returns the bytes from reading a file at fullFilePath.
+// Implements the Loader interface.
+func (l *fileLoader) Load(fullFilePath string) ([]byte, error) {
+	// Validate path to load from is a full file path.
+	if !filepath.IsAbs(fullFilePath) {
+		return nil, fmt.Errorf("Attempting to load file without full file path: %s\n", fullFilePath)
+	}
+	return l.fs.ReadFile(fullFilePath)
+}