Wip: Remove allowNested, add FileUtil

sop-java-picocli/src/main/java/sop/cli/picocli/FileUtil.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2021 Paul Schaub.
+ *
+ * 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 sop.cli.picocli;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+
+import sop.exception.SOPGPException;
+
+public class FileUtil {
+
+    private static final String ERROR_AMBIGUOUS = "File name '%s' is ambiguous. File with the same name exists on the filesystem.";
+    private static final String ERROR_ENV_FOUND = "Environment variable '%s' not set.";
+    private static final String ERROR_OUTPUT_EXISTS = "Output file '%s' already exists.";
+    private static final String ERROR_INPUT_NOT_EXIST = "File '%s' does not exist.";
+    private static final String ERROR_CANNOT_CREATE_FILE = "Output file '%s' cannot be created: %s";
+
+    public static final String PRFX_ENV = "@ENV:";
+    public static final String PRFX_FD = "@FD:";
+
+    public static File getFile(String fileName) {
+        if (fileName == null) {
+            throw new NullPointerException("File name cannot be null.");
+        }
+
+        if (fileName.startsWith(PRFX_ENV)) {
+
+            if (new File(fileName).exists()) {
+                throw new SOPGPException.AmbiguousInput(String.format(ERROR_AMBIGUOUS, fileName));
+            }
+
+            String envName = fileName.substring(PRFX_ENV.length());
+            String envValue = System.getenv(envName);
+            if (envValue == null) {
+                throw new IllegalArgumentException(String.format(ERROR_ENV_FOUND, envName));
+            }
+            return new File(envValue);
+        } else if (fileName.startsWith(PRFX_FD)) {
+
+            if (new File(fileName).exists()) {
+                throw new SOPGPException.AmbiguousInput(String.format(ERROR_AMBIGUOUS, fileName));
+            }
+
+            throw new IllegalArgumentException("File descriptors not supported.");
+        }
+
+        return new File(fileName);
+    }
+
+    public static FileInputStream getFileInputStream(String fileName) {
+        File file = getFile(fileName);
+        try {
+            FileInputStream inputStream = new FileInputStream(file);
+            return inputStream;
+        } catch (FileNotFoundException e) {
+            throw new SOPGPException.MissingInput(String.format(ERROR_INPUT_NOT_EXIST, fileName), e);
+        }
+    }
+
+    public static File createNewFileOrThrow(File file) throws IOException {
+        if (file == null) {
+            throw new NullPointerException("File cannot be null.");
+        }
+
+        try {
+            if (!file.createNewFile()) {
+                throw new SOPGPException.OutputExists(String.format(ERROR_OUTPUT_EXISTS, file.getAbsolutePath()));
+            }
+        } catch (IOException e) {
+            throw new IOException(String.format(ERROR_CANNOT_CREATE_FILE, file.getAbsolutePath(), e.getMessage()));
+        }
+        return file;
+    }
+}