Remove `push` from `Storage`

Since every line is allocated at startup anyways, the `push` method on
`Storage` has been removed and instead of pushing to the vector the
initialization has been moved to the `with_capacity` method.

This has the advantage that we don't need to keep track of the `len` in
push (like adding one), but we just need to worry about
growing/shrinking the visible area.

src/grid/mod.rs

@@ -118,17 +118,7 @@ pub enum Scroll {
 
 impl<T: Copy + Clone> Grid<T> {
     pub fn new(lines: index::Line, cols: index::Column, scrollback: usize, template: T) -> Grid<T> {
-        let mut raw = Storage::with_capacity(*lines + scrollback, lines);
-
-        // Allocate all lines in the buffer, including scrollback history
-        //
-        // TODO (jwilm) Allocating each line at this point is expensive and
-        // delays startup. A nice solution might be having `Row` delay
-        // allocation until it's actually used.
-        for _ in 0..raw.len() {
-            raw.push(Row::new(cols, &template));
-        }
-
+        let raw = Storage::with_capacity(*lines + scrollback, lines, Row::new(cols, &template));
         Grid {
             raw,
             cols,

src/grid/storage.rs

@@ -67,9 +67,18 @@ impl<T: PartialEq> ::std::cmp::PartialEq for Storage<T> {
 
 impl<T> Storage<T> {
     #[inline]
-    pub fn with_capacity(cap: usize, lines: Line) -> Storage<T> {
+    pub fn with_capacity(cap: usize, lines: Line, template: T) -> Storage<T>
+    where
+        T: Clone,
+    {
+        // Allocate all lines in the buffer, including scrollback history
+        //
+        // TODO (jwilm) Allocating each line at this point is expensive and
+        // delays startup. A nice solution might be having `Row` delay
+        // allocation until it's actually used.
+        let inner = vec![template; cap];
         Storage {
-            inner: Vec::with_capacity(cap),
+            inner,
             zero: 0,
             visible_lines: lines - 1,
             len: cap,
@@ -120,11 +129,6 @@ impl<T> Storage<T> {
         self.visible_lines = next - 1;
     }
 
-    #[inline]
-    pub fn push(&mut self, item: T) {
-        self.inner.push(item)
-    }
-
     #[inline]
     pub fn len(&self) -> usize {
         self.len