Fix issue with the git log

The old code was assuming that the buffer was not going to change, this is not
true with the current impl though where the list is shifted and ybase and ydisp
need to be compensated for that.

src/utils/CircularList.ts

@@ -84,12 +84,16 @@ export class CircularList<T> {
     this._array[this._getCyclicIndex(this._length)] = value;
     if (this._length === this.maxLength) {
       this._startIndex++;
+      if (this._startIndex === this.maxLength) {
+        this._startIndex = 0;
+      }
     } else {
       this._length++;
     }
   }
 
   public pop(): T {
+    // TODO: This isn't popping from the array, only returning
     return this._array[this._getCyclicIndex(this._length-- - 1)];
   }
 
@@ -118,6 +122,13 @@ export class CircularList<T> {
     }
   }
 
+  public trimStart(count: number): void {
+    // TODO: Error handling
+    // TODO: Testing (if we need this)
+    this._startIndex += count;
+    this._length--;
+  }
+
   private _getCyclicIndex(index: number): number {
     return (this._startIndex + index) % this.maxLength;
   }

src/xterm.js

@@ -1238,6 +1238,7 @@ Terminal.prototype.scroll = function() {
     this.ybase++;
   }
 
+  // TODO: Why is this done twice?
   if (!this.userScrolling) {
     this.ydisp = this.ybase;
   }
@@ -3164,21 +3165,30 @@ Terminal.prototype.index = function() {
 
 /**
  * ESC M Reverse Index (RI is 0x8d).
+ *
+ * Move the cursor up one row, inserting a new blank line if necessary.
  */
 Terminal.prototype.reverseIndex = function() {
   var j;
-  this.y--;
-  if (this.y < this.scrollTop) {
-    this.y++;
+  if (this.y === this.scrollTop) {
     // possibly move the code below to term.reverseScroll();
     // test: echo -ne '\e[1;1H\e[44m\eM\e[0m'
     // blankLine(true) is xterm/linux behavior
+    if (this.lines.length === this.lines.maxLength) {
+      // Trim the start of lines to make room for the new temporary row
+      // TODO: This section could be optimized by introducing a CircularList function that inserts,
+      //       deletes and shifts elements to accomplish this task.
+      this.lines.trimStart(1);
+      this.ybase -= 1;
+      this.ydisp -= 1;
+    }
     this.lines.splice(this.y + this.ybase, 0, this.blankLine(true));
     j = this.rows - 1 - this.scrollBottom;
     this.lines.splice(this.rows - 1 + this.ybase - j + 1, 1);
-    // this.maxRange();
     this.updateRange(this.scrollTop);
     this.updateRange(this.scrollBottom);
+  } else {
+    this.y--;
   }
   this.state = normal;
 };
@@ -3695,6 +3705,14 @@ Terminal.prototype.insertLines = function(params) {
   j = this.rows - 1 + this.ybase - j + 1;
 
   while (param--) {
+    if (this.lines.length === this.lines.maxLength) {
+      // Trim the start of lines to make room for the new temporary row
+      // TODO: This section could be optimized by introducing a CircularList function that inserts,
+      //       deletes and shifts elements to accomplish this task.
+      this.lines.trimStart(1);
+      this.ybase -= 1;
+      this.ydisp -= 1;
+    }
     // test: echo -e '\e[44m\e[1L\e[0m'
     // blankLine(true) - xterm/linux behavior
     this.lines.splice(row, 0, this.blankLine(true));
@@ -3722,6 +3740,14 @@ Terminal.prototype.deleteLines = function(params) {
   j = this.rows - 1 + this.ybase - j;
 
   while (param--) {
+    if (this.lines.length === this.lines.maxLength) {
+      // Trim the start of lines to make room for the new temporary row
+      // TODO: This section could be optimized by introducing a CircularList function that inserts,
+      //       deletes and shifts elements to accomplish this task.
+      this.lines.trimStart(1);
+      this.ybase -= 1;
+      this.ydisp -= 1;
+    }
     // test: echo -e '\e[44m\e[1M\e[0m'
     // blankLine(true) - xterm/linux behavior
     this.lines.splice(j + 1, 0, this.blankLine(true));
@@ -3748,8 +3774,8 @@ Terminal.prototype.deleteChars = function(params) {
   ch = [this.eraseAttr(), ' ', 1]; // xterm
 
   while (param--) {
-    this.lines[row].splice(this.x, 1);
-    this.lines[row].push(ch);
+    this.lines.get(row).splice(this.x, 1);
+    this.lines.get(row).push(ch);
   }
 };
 
@@ -4774,8 +4800,8 @@ Terminal.prototype.insertColumns = function() {
 
   while (param--) {
     for (i = this.ybase; i < l; i++) {
-      this.lines[i].splice(this.x + 1, 0, ch);
-      this.lines[i].pop();
+      this.lines.get(i).splice(this.x + 1, 0, ch);
+      this.lines.get(i).pop();
     }
   }
 
@@ -4796,8 +4822,8 @@ Terminal.prototype.deleteColumns = function() {
 
   while (param--) {
     for (i = this.ybase; i < l; i++) {
-      this.lines[i].splice(this.x, 1);
-      this.lines[i].push(ch);
+      this.lines.get(i).splice(this.x, 1);
+      this.lines.get(i).push(ch);
     }
   }