make Backend::get_mboxes return struct instead of trait (#340)

This step was necessary to move logic from CLI to lib. Indeed, the
trait returned by get_mboxes needed to implement Table, which is
related to the CLI module only.

lib/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2021"
 imap-backend = ["imap", "imap-proto"]
 maildir-backend = ["maildir", "md5"]
 notmuch-backend = ["notmuch", "maildir-backend"]
-default = ["imap-backend", "maildir-backend"]
+default = ["imap-backend", "maildir-backend", "notmuch-backend"]
 
 [dependencies]
 lettre = { version = "0.10.0-rc.1", features = ["serde"] }

lib/src/lib.rs

@@ -1,2 +1,4 @@
-pub mod account;
 mod process;
+
+pub mod account;
+pub mod mbox;

lib/src/mbox/mbox.rs

@@ -0,0 +1,19 @@
+use serde::Serialize;
+use std::fmt;
+
+/// Represents the mailbox.
+#[derive(Debug, Default, PartialEq, Eq, Serialize)]
+pub struct Mbox {
+    /// Represents the mailbox hierarchie delimiter.
+    pub delim: String,
+    /// Represents the mailbox name.
+    pub name: String,
+    /// Represents the mailbox description.
+    pub desc: String,
+}
+
+impl fmt::Display for Mbox {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.name)
+    }
+}

lib/src/mbox/mboxes.rs

@@ -0,0 +1,25 @@
+use serde::Serialize;
+use std::ops::{Deref, DerefMut};
+
+use super::Mbox;
+
+/// Represents the list of mailboxes.
+#[derive(Debug, Default, Serialize)]
+pub struct Mboxes {
+    #[serde(rename = "response")]
+    pub mboxes: Vec<Mbox>,
+}
+
+impl Deref for Mboxes {
+    type Target = Vec<Mbox>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.mboxes
+    }
+}
+
+impl DerefMut for Mboxes {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.mboxes
+    }
+}

lib/src/mbox/mod.rs

@@ -0,0 +1,5 @@
+mod mbox;
+pub use mbox::*;
+
+mod mboxes;
+pub use mboxes::*;