Improve select-to-comment behavior in Firefox and on unified diffs

Summary:
Ref T13513.

  - Firefox represents multiple selected rows as a discontinuous range. Accommodate this.
  - Unified diffs don't have a "copy" marker. Do something sort-of-reasonable for them.

Test Plan:
  - Selected multiple lines of content in Firefox, got an option to add a comment.
  - Selected content in unified mode, got an option to add a comment.

Maniphest Tasks: T13513

Differential Revision: https://secure.phabricator.com/D21249

resources/celerity/map.php

@@ -13,7 +13,7 @@ return array(
     'core.pkg.js' => '0efaf0ac',
     'dark-console.pkg.js' => '187792c2',
     'differential.pkg.css' => 'd71d4531',
-    'differential.pkg.js' => '06a7949c',
+    'differential.pkg.js' => 'ac6914bb',
     'diffusion.pkg.css' => '42c75c37',
     'diffusion.pkg.js' => 'a98c0bf7',
     'maniphest.pkg.css' => '35995d6d',
@@ -380,7 +380,7 @@ return array(
     'rsrc/js/application/dashboard/behavior-dashboard-query-panel-select.js' => '1e413dc9',
     'rsrc/js/application/dashboard/behavior-dashboard-tab-panel.js' => '0116d3e8',
     'rsrc/js/application/diff/DiffChangeset.js' => '20715b98',
-    'rsrc/js/application/diff/DiffChangesetList.js' => '4a3639a1',
+    'rsrc/js/application/diff/DiffChangesetList.js' => '9d5b137e',
     'rsrc/js/application/diff/DiffInline.js' => '6227a0e3',
     'rsrc/js/application/diff/DiffPathView.js' => '8207abf9',
     'rsrc/js/application/diff/DiffTreeView.js' => '5d83623b',
@@ -775,7 +775,7 @@ return array(
     'phabricator-darkmessage' => '26cd4b73',
     'phabricator-dashboard-css' => '5a205b9d',
     'phabricator-diff-changeset' => '20715b98',
-    'phabricator-diff-changeset-list' => '4a3639a1',
+    'phabricator-diff-changeset-list' => '9d5b137e',
     'phabricator-diff-inline' => '6227a0e3',
     'phabricator-diff-path-view' => '8207abf9',
     'phabricator-diff-tree-view' => '5d83623b',
@@ -1327,11 +1327,6 @@ return array(
     '490e2e2e' => array(
       'phui-oi-list-view-css',
     ),
-    '4a3639a1' => array(
-      'javelin-install',
-      'phuix-button-view',
-      'phabricator-diff-tree-view',
-    ),
     '4a7fb02b' => array(
       'javelin-behavior',
       'javelin-dom',
@@ -1821,6 +1816,11 @@ return array(
       'javelin-uri',
       'phabricator-textareautils',
     ),
+    '9d5b137e' => array(
+      'javelin-install',
+      'phuix-button-view',
+      'phabricator-diff-tree-view',
+    ),
     '9f081f05' => array(
       'javelin-behavior',
       'javelin-dom',

webroot/rsrc/js/application/diff/DiffChangesetList.js

@@ -2232,34 +2232,36 @@ JX.install('DiffChangesetList', {
     _updateSourceSelection: function() {
       var ranges = this._getSelectedRanges();
 
-      // If we have zero or more than one range, don't do anything.
+      // In Firefox, selecting multiple rows gives us multiple ranges. In
-      if (ranges.length === 1) {
+      // Safari and Chrome, we get a single range.
-        for (var ii = 0; ii < ranges.length; ii++) {
+      if (!ranges.length) {
-          var range = ranges[ii];
+        this._setSourceSelection(null, null);
+        return;
+      }
 
-          var head = range.startContainer;
+      var min = 0;
-          var last = range.endContainer;
+      var max = ranges.length - 1;
+
+      var head = ranges[min].startContainer;
+      var last = ranges[max].endContainer;
 
       var head_loc = this._getFragmentLocation(head);
       var last_loc = this._getFragmentLocation(last);
 
       if (head_loc === null || last_loc === null) {
-            break;
+        this._setSourceSelection(null, null);
+        return;
       }
 
       if (head_loc.changesetID !== last_loc.changesetID) {
-            break;
+        this._setSourceSelection(null, null);
-          }
-
-          head_loc.offset += range.startOffset;
-          last_loc.offset += range.endOffset;
-
-          this._setSourceSelection(head_loc, last_loc);
         return;
       }
-      }
 
-      this._setSourceSelection(null, null);
+      head_loc.offset += ranges[min].startOffset;
+      last_loc.offset += ranges[max].endOffset;
+
+      this._setSourceSelection(head_loc, last_loc);
     },
 
     _setSourceSelection: function(start, end) {
@@ -2382,6 +2384,8 @@ JX.install('DiffChangesetList', {
       // Find the line number and display column for the fragment.
       var line = null;
       var column_count = -1;
+      var has_new = false;
+      var has_old = false;
       var offset = null;
       var target_node = null;
       var td;
@@ -2415,6 +2419,18 @@ JX.install('DiffChangesetList', {
         while (cursor) {
           if (cursor.getAttribute('data-copy-mode')) {
             column_count++;
+          } else {
+            // In unified mode, the content column isn't currently marked
+            // with an attribute, and we can't count content columns anyway.
+            // Keep track of whether or not we see a "NL" (New Line) column
+            // and/or an "OL" (Old Line) column to try to puzzle out which
+            // side of the display change we're on.
+
+            if (cursor.id.match(/NL/)) {
+              has_new = true;
+            } else if (cursor.id.match(/OL/)) {
+              has_old = true;
+            }
           }
 
           var n = parseInt(cursor.getAttribute('data-n'));
@@ -2434,8 +2450,16 @@ JX.install('DiffChangesetList', {
         }
 
         if (column_count < 0) {
+          if (has_new || has_old) {
+            if (has_new) {
+              column_count = 1;
+            } else {
+              column_count = 0;
+            }
+          } else {
             return null;
           }
+        }
 
         var seen = 0;
         for (var ii = 0; ii < td.childNodes.length; ii++) {