Implement new file device interface

This is a complete redesign of the file device. The most notable
addition is the ability to ascend and descend the file tree.

1 files changed, 43 insertions, 0 deletions

diff --git a/src/devices/file/operations.rs b/src/devices/file/operations.rs
new file mode 100644
index 0000000..f33509b
--- /dev/null
+++ b/src/devices/file/operations.rs
@@ -0,0 +1,43 @@
+use std::io::ErrorKind;
+use std::path::Path;
+
+pub fn entry_exists(source: &Path) -> bool {
+    std::fs::metadata(source).is_ok()
+}
+
+// Delete a file or folder, returning true if successful.
+pub fn delete_entry(source: &Path) -> bool {
+    match std::fs::remove_file(source) {
+        Ok(_) => true,
+        Err(e) => match e.kind() {
+            ErrorKind::NotFound => true,
+            ErrorKind::IsADirectory => match std::fs::remove_dir_all(source) {
+                Ok(_) => true,
+                Err(e) => match e.kind() {
+                    ErrorKind::NotFound => true,
+                    _ => false,
+                }
+            }
+            _ => false,
+        }
+    }
+}
+
+pub fn move_entry(source: &Path, destination: &Path) -> bool {
+    if !entry_exists(source) || entry_exists(destination) {
+        return false;
+    }
+    std::fs::rename(source, destination).is_ok()
+}
+
+pub fn create_file(destination: &Path) -> bool {
+    if entry_exists(destination) {
+        false
+    } else {
+        if let Some(parent_path) = destination.parent() {
+            let _ = std::fs::create_dir_all(parent_path);
+        }
+        std::fs::OpenOptions::new().write(true).create_new(true)
+            .open(destination).is_ok()
+    }
+}