From b3508f5dc3680a77e1535890fbe22446fcebe626 Mon Sep 17 00:00:00 2001
From: Matthias Beyer <mail@beyermatthias.de>
Date: Sun, 18 Oct 2015 21:59:17 +0200
Subject: [PATCH] Add trait Storage

---
 src/main.rs    |  1 +
 src/storage.rs | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)
 create mode 100644 src/storage.rs

diff --git a/src/main.rs b/src/main.rs
index aa577cdb..b508b7f8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,6 +8,7 @@ mod cli;
 mod error;
 mod runtime;
 mod module;
+mod storage;
 
 fn main() {
     let mut config = Config::new();
diff --git a/src/storage.rs b/src/storage.rs
new file mode 100644
index 00000000..12d743ca
--- /dev/null
+++ b/src/storage.rs
@@ -0,0 +1,69 @@
+pub use std::path::Path;
+pub use std::fs::File;
+
+pub use runtime::Runtime;
+pub use error::ImagError;
+pub use error::ImagErrorBase;
+
+pub struct StorageError {
+    base : ImagErrorBase,
+    backendname : String,
+}
+
+impl StorageError {
+
+    pub fn new<T : StorageBackend>(backend : &T, short: String, long: String) -> StorageError {
+        StorageError {
+            base: ImagErrorBase {
+                shortdesc: short,
+                longdesc: long,
+            },
+            backendname: backend.name()
+        }
+    }
+
+}
+
+impl<'a> ImagError<'a> for StorageError {
+
+    fn print(&self, rt: &Runtime) {
+        if self.base.longdesc.is_empty() {
+            let s = format!("Backend {}: {}\n\n{}\n\n",
+                            self.backendname,
+                            self.base.shortdesc,
+                            self.base.longdesc);
+            rt.print(&s)
+        } else {
+            let s = format!("Backend {}: {}\n",
+                            self.backendname,
+                            self.base.shortdesc);
+            rt.print(&s)
+        }
+    }
+
+    fn print_short(&self, rt : &Runtime) {
+        let s = format!("Backend {}: {}\n",
+                        self.backendname,
+                        self.base.shortdesc);
+        rt.print(&s)
+    }
+
+    fn print_long(&self, rt : &Runtime) {
+        let s = format!("Backend {}: {}\n\n{}\n\n",
+                        self.backendname,
+                        self.base.shortdesc,
+                        self.base.longdesc);
+        rt.print(&s)
+    }
+}
+
+pub trait StorageBackend {
+
+    fn name(&self) -> String;
+
+    fn create(&self, file : File)   -> Option<StorageError>;
+    fn read(&self, path: Path)      -> Result<File, StorageError>;
+    fn update(&self, file : File)   -> Option<StorageError>;
+    fn destroy(&self, path: Path)   -> Option<StorageError>;
+
+}