Add `ToStr` and `ToStaticStr` traits.

Allow easy mapping of borrowed C strings to borrowed strings with
appropriate lifetimes.

I have some doubts about this, as I'm not 100% on how lifetimes interact
with the notmuch-provided strings yet.

2 files changed, 32 insertions, 1 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 0f88f60..f490df7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,4 @@
-#![feature(libc)]
+#![feature(core, libc)]
 extern crate libc;
 
 #[macro_use]
diff --git a/src/utils.rs b/src/utils.rs
index 77e6e5e..ad8bcac 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -1,6 +1,37 @@
+use std::{
+    ffi,
+    str,
+};
+
+use libc;
+
 pub trait NotmuchEnum {
     type NotmuchT;
 
     fn from_notmuch_t(notmuch_t: Self::NotmuchT) -> Self;
     fn to_notmuch_t(self) -> Self::NotmuchT;
 }
+
+pub trait ToStr {
+    fn to_str(&self) -> Result<&str, str::Utf8Error>;
+}
+
+impl ToStr for *const libc::c_char {
+    fn to_str(&self) -> Result<&str, str::Utf8Error> {
+        str::from_utf8(unsafe {
+            ffi::CStr::from_ptr(*self)
+        }.to_bytes())
+    }
+}
+
+pub trait ToStaticStr {
+    fn to_static_str(&self) -> Result<&'static str, str::Utf8Error>;
+}
+
+impl ToStaticStr for *const libc::c_char {
+    fn to_static_str(&self) -> Result<&'static str, str::Utf8Error> {
+        str::from_utf8(unsafe {
+            ffi::CStr::from_ptr(*self)
+        }.to_bytes())
+    }
+}