1 files changed, 54 insertions, 0 deletions
diff --git a/cli/src/chain.rs b/cli/src/chain.rs
new file mode 100644
index 0000000..a8014b8
--- /dev/null
+++ b/cli/src/chain.rs
@@ -0,0 +1,54 @@
+use std::io::{Read, Result, Write};
+
+pub struct Chain<T> {
+    elem: Vec<T>,
+    index: usize,
+}
+
+impl<T: Read> Read for Chain<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        loop {
+            match self.elem.get_mut(self.index) {
+                Some(ref mut r) => {
+                    match try!(r.read(buf)) {
+                        0 => self.index += 1,
+                        n => return Ok(n),
+                    }
+                }
+                None => return Ok(0),
+            }
+        }
+    }
+}
+
+impl<T: Write> Write for Chain<T> {
+    fn write(&mut self, buf: &[u8]) -> Result<usize> {
+        loop {
+            match self.elem.get_mut(self.index) {
+                Some(ref mut r) => {
+                    match try!(r.write(buf)) {
+                        0 => self.index += 1,
+                        n => return Ok(n),
+                    }
+                }
+                None => return Ok(0),
+            }
+        }
+    }
+
+    fn flush(&mut self) -> Result<()> {
+        match self.elem.get_mut(self.index) {
+            Some(ref mut r) => r.flush(),
+            None => Ok(()),
+        }
+    }
+}
+
+impl<T> Chain<T> {
+    pub fn new(elem: Vec<T>) -> Chain<T> {
+        Chain {
+            index: 0,
+            elem: elem,
+        }
+    }
+}