add CodeMirror's merge.js addon + modify imported diff code for compatibility

src/lib/codemirror/addon/merge/merge.css

@@ -0,0 +1,113 @@
+.CodeMirror-merge {
+  position: relative;
+  border: 1px solid #ddd;
+  white-space: pre;
+}
+
+.CodeMirror-merge, .CodeMirror-merge .CodeMirror {
+  height: 350px;
+}
+
+.CodeMirror-merge-2pane .CodeMirror-merge-pane { width: 47%; }
+.CodeMirror-merge-2pane .CodeMirror-merge-gap { width: 6%; }
+.CodeMirror-merge-3pane .CodeMirror-merge-pane { width: 31%; }
+.CodeMirror-merge-3pane .CodeMirror-merge-gap { width: 3.5%; }
+
+.CodeMirror-merge-pane {
+  display: inline-block;
+  white-space: normal;
+  vertical-align: top;
+}
+.CodeMirror-merge-pane-rightmost {
+  position: absolute;
+  right: 0px;
+  z-index: 1;
+}
+
+.CodeMirror-merge-gap {
+  z-index: 2;
+  display: inline-block;
+  height: 100%;
+  -moz-box-sizing: border-box;
+  box-sizing: border-box;
+  overflow: hidden;
+  border-left: 1px solid #ddd;
+  border-right: 1px solid #ddd;
+  position: relative;
+  background: #f8f8f8;
+}
+
+.CodeMirror-merge-scrolllock-wrap {
+  position: absolute;
+  bottom: 0; left: 50%;
+}
+.CodeMirror-merge-scrolllock {
+  position: relative;
+  left: -50%;
+  cursor: pointer;
+  color: #555;
+  line-height: 1;
+}
+
+.CodeMirror-merge-copybuttons-left, .CodeMirror-merge-copybuttons-right {
+  position: absolute;
+  left: 0; top: 0;
+  right: 0; bottom: 0;
+  line-height: 1;
+}
+
+.CodeMirror-merge-copy {
+  position: absolute;
+  cursor: pointer;
+  color: #44c;
+  z-index: 3;
+}
+
+.CodeMirror-merge-copy-reverse {
+  position: absolute;
+  cursor: pointer;
+  color: #44c;
+}
+
+.CodeMirror-merge-copybuttons-left .CodeMirror-merge-copy { left: 2px; }
+.CodeMirror-merge-copybuttons-right .CodeMirror-merge-copy { right: 2px; }
+
+.CodeMirror-merge-r-inserted, .CodeMirror-merge-l-inserted {
+  background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAMAAAACCAYAAACddGYaAAAAGUlEQVQI12MwuCXy3+CWyH8GBgYGJgYkAABZbAQ9ELXurwAAAABJRU5ErkJggg==);
+  background-position: bottom left;
+  background-repeat: repeat-x;
+}
+
+.CodeMirror-merge-r-deleted, .CodeMirror-merge-l-deleted {
+  background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAMAAAACCAYAAACddGYaAAAAGUlEQVQI12M4Kyb2/6yY2H8GBgYGJgYkAABURgPz6Ks7wQAAAABJRU5ErkJggg==);
+  background-position: bottom left;
+  background-repeat: repeat-x;
+}
+
+.CodeMirror-merge-r-chunk { background: #ffffe0; }
+.CodeMirror-merge-r-chunk-start { border-top: 1px solid #ee8; }
+.CodeMirror-merge-r-chunk-end { border-bottom: 1px solid #ee8; }
+.CodeMirror-merge-r-connect { fill: #ffffe0; stroke: #ee8; stroke-width: 1px; }
+
+.CodeMirror-merge-l-chunk { background: #eef; }
+.CodeMirror-merge-l-chunk-start { border-top: 1px solid #88e; }
+.CodeMirror-merge-l-chunk-end { border-bottom: 1px solid #88e; }
+.CodeMirror-merge-l-connect { fill: #eef; stroke: #88e; stroke-width: 1px; }
+
+.CodeMirror-merge-l-chunk.CodeMirror-merge-r-chunk { background: #dfd; }
+.CodeMirror-merge-l-chunk-start.CodeMirror-merge-r-chunk-start { border-top: 1px solid #4e4; }
+.CodeMirror-merge-l-chunk-end.CodeMirror-merge-r-chunk-end { border-bottom: 1px solid #4e4; }
+
+.CodeMirror-merge-collapsed-widget:before {
+  content: "(...)";
+}
+.CodeMirror-merge-collapsed-widget {
+  cursor: pointer;
+  color: #88b;
+  background: #eef;
+  border: 1px solid #ddf;
+  font-size: 90%;
+  padding: 0 3px;
+  border-radius: 4px;
+}
+.CodeMirror-merge-collapsed-line .CodeMirror-gutter-elt { display: none; }

src/lib/diff/swatinem_diff.js

@@ -1,17 +1,53 @@
-/* vim: set shiftwidth=2 tabstop=2 noexpandtab textwidth=80 wrap : */
+/*******************************************************************************
-"use strict";
 
-module.exports = diff;
+  Key portions of code below was borrowed from:
+    https://github.com/Swatinem/diff
 
-function diff(a, b, eql) {
+  License is LGPL3 (thanks!) as per:
-    if (!eql)
+    https://github.com/Swatinem/diff/blob/b58391504759/README.md
-        eql = function (a, b) { return a === b; };
 
-    var d = new Diff(a, b, eql);
+  I chose to pick this implementation over
+  https://github.com/google/diff-match-patch as suggested by CodeMirror
+  because:
+
+  - Code is clean and simple to read -- useful when unfamiliar with the diff
+    algorithm, this makes changing the code easier if/when needed.
+
+  - Smaller -- diff_match_patch comes with an extended API most of which is
+    of no use to the current project.
+    - diff_match_patch uncompressed: 74.7 KB
+    - Swatinem's diff uncompressed: 3.66 KB
+
+  - I can easily adapt Swatinem's diff to deal with arrays of strings, which
+    is best suited for the current project -- it natively work with arrays.
+
+  I removed portions of code which are of no use for the current project.
+
+  I modified the diff script generator (Diff.prototype.editscript) since I
+  need to generate a script which is compatible with the output of the
+  diff_match_patch, as expected by CodeMirror.
+
+**/
+
+'use strict';
+
+(function(context) {
+
+    // CodeMirror expect these globals:
+    context.DIFF_INSERT = 1;
+    context.DIFF_DELETE = -1;
+    context.DIFF_EQUAL = 0;
+    context.diff_match_patch = function(){};
+
+    context.diff_match_patch.prototype.diff_main = function(a, b) {
+        if ( a === b ) { return [ [ 0, a ] ]; }
+        var aa = a.match(/\n|[^\n]+\n?/g) || [];
+        var bb = b.match(/\n|[^\n]+\n?/g) || [];
+        var d = new Diff(aa, bb, eqlDefault);
         return d.editscript();
-}
+    };
 
-diff.Diff = Diff;
+    function eqlDefault(a, b) { return a === b; }
 
     function Diff(a, b, eql) {
         this.a = a;
@@ -28,11 +64,6 @@ function Diff(a, b, eql) {
         this.lcs(0, a.length, 0, b.length);
     }
 
-Diff.NOOP    = 'nop';
-Diff.DELETE  = 'del';
-Diff.INSERT  = 'ins';
-Diff.REPLACE = 'rep';
-
     Diff.prototype.editscript = function Diff_editscript() {
         var moda = this.moda, modb = this.modb;
         var astart = 0, aend = moda.length;
@@ -41,21 +72,22 @@ Diff.prototype.editscript = function Diff_editscript() {
         while (astart < aend || bstart < bend) {
             if (astart < aend && bstart < bend) {
                 if (!moda[astart] && !modb[bstart]) {
-                result.push(Diff.NOOP);
+                    result.push([ 0, this.a[astart] ]);
                     astart++; bstart++;
                     continue;
                 } else if (moda[astart] && modb[bstart]) {
-                result.push(Diff.REPLACE);
+                    result.push([ -1, this.a[astart] ]);
+                    result.push([ 1, this.b[bstart] ]);
                     astart++; bstart++;
                     continue;
                 }
             }
             if (astart < aend && (bstart >= bend || moda[astart])) {
-            result.push(Diff.DELETE);
+                result.push([ -1, this.a[astart] ]);
                 astart++;
             }
             if (bstart < bend && (astart >= aend || modb[bstart])) {
-            result.push(Diff.INSERT);
+                result.push([ 1, this.b[bstart] ]);
                 bstart++;
             }
         }
@@ -171,3 +203,5 @@ Diff.prototype.snake = function Diff_snake(astart, aend, bstart, bend) {
         }
     };
 
+    return Diff;
+})(self);