Bug 998941 - part 1-7: Make HTMLEditor set InputEvent.data to serialized color value when InputEvent.inputType is "formatBackColor" or "formatForeColor" r=smaug,m_kato,emilio

Although neither Chrome nor Safari does not set InputEvent.data when the event
is caused by `document.execCommand()` with `backColor`, `foreColor` nor
`hiliteColor`, Safari supports styling color with touchbar and in that case,
Safari sets it (*1).

Additionally, currently Safari uses `rgb()` to represents a color value and
using same rule to serializing color value for CSS OM matches Safari's behavior
and can represent any valid color values.

This patch makes given color value parsed and then serialized with same code
in style system.  If the value is `currentcolor`, `inherit`, `initial` or `reset`, sets
the value as-is for now.  Additionally, when given value is invalid, sets the value
as-is for forward compatibility.

Note that automated tests will be added into input-events-exec-command.html
by the last patch.

1. https://github.com/w3c/input-events/issues/94#issuecomment-461061517

Differential Revision: https://phabricator.services.mozilla.com/D19295

--HG--
extra : moz-landing-system : lando

editor/libeditor/EditorBase.cpp

@@ -44,6 +44,7 @@
 #include "mozilla/RangeBoundary.h"      // for RawRangeBoundary, RangeBoundary
 #include "mozilla/dom/Selection.h"      // for Selection, etc.
 #include "mozilla/Services.h"           // for GetObserverService
+#include "mozilla/ServoCSSParser.h"     // for ServoCSSParser
 #include "mozilla/TextComposition.h"    // for TextComposition
 #include "mozilla/TextInputListener.h"  // for TextInputListener
 #include "mozilla/TextServicesDocument.h"  // for TextServicesDocument
@@ -103,6 +104,7 @@
 #include "nsStyleConsts.h"     // for NS_STYLE_DIRECTION_RTL, etc.
 #include "nsStyleStruct.h"     // for nsStyleDisplay, nsStyleText, etc.
 #include "nsStyleStructFwd.h"  // for nsIFrame::StyleUIReset, etc.
+#include "nsStyleUtil.h"       // for nsStyleUtil
 #include "nsTextNode.h"        // for nsTextNode
 #include "nsThreadUtils.h"     // for nsRunnable
 #include "prtime.h"            // for PR_Now
@@ -4867,4 +4869,38 @@ EditorBase::AutoEditActionDataSetter::~AutoEditActionDataSetter() {
   mEditorBase.mEditActionData = mParentData;
 }
 
+void EditorBase::AutoEditActionDataSetter::SetColorData(
+    const nsAString& aData) {
+  if (aData.IsEmpty()) {
+    // When removing color/background-color, let's use empty string.
+    MOZ_ASSERT(!EmptyString().IsVoid());
+    mData = EmptyString();
+    return;
+  }
+
+  bool wasCurrentColor = false;
+  nscolor color = NS_RGB(0, 0, 0);
+  if (!ServoCSSParser::ComputeColor(nullptr, NS_RGB(0, 0, 0), aData, &color,
+                                    &wasCurrentColor)) {
+    // If we cannot parse aData, let's set original value as-is.  It could be
+    // new format defined by newer spec.
+    MOZ_ASSERT(!aData.IsVoid());
+    mData = aData;
+    return;
+  }
+
+  // If it's current color, we cannot resolve actual current color here.
+  // So, let's return "currentcolor" keyword, but let's use it as-is because
+  // there is no agreement between browser vendors.
+  if (wasCurrentColor) {
+    MOZ_ASSERT(!aData.IsVoid());
+    mData = aData;
+    return;
+  }
+
+  // Get serialized color value (i.e., "rgb()" or "rgba()").
+  nsStyleUtil::GetSerializedColorValue(color, mData);
+  MOZ_ASSERT(!mData.IsVoid());
+}
+
 }  // namespace mozilla

editor/libeditor/EditorBase.h

@@ -652,6 +652,8 @@ class EditorBase : public nsIEditor,
     void SetData(const nsAString& aData) { mData = aData; }
     const nsString& GetData() const { return mData; }
 
+    void SetColorData(const nsAString& aData);
+
     void SetTopLevelEditSubAction(EditSubAction aEditSubAction,
                                   EDirection aDirection = eNone) {
       mTopLevelEditSubAction = aEditSubAction;

editor/libeditor/HTMLStyleEditor.cpp

@@ -73,6 +73,10 @@ nsresult HTMLEditor::SetInlinePropertyAsAction(nsAtom& aProperty,
       // XXX Should we trim unnecessary whitespaces?
       editActionData.SetData(aValue);
       break;
+    case EditAction::eSetColorProperty:
+    case EditAction::eSetBackgroundColorPropertyInline:
+      editActionData.SetColorData(aValue);
+      break;
     default:
       break;
   }
@@ -120,6 +124,10 @@ HTMLEditor::SetInlineProperty(const nsAString& aProperty,
       // XXX Should we trim unnecessary whitespaces?
       editActionData.SetData(aValue);
       break;
+    case EditAction::eSetColorProperty:
+    case EditAction::eSetBackgroundColorPropertyInline:
+      editActionData.SetColorData(aValue);
+      break;
     default:
       break;
   }
@@ -1246,6 +1254,10 @@ nsresult HTMLEditor::RemoveInlinePropertyAsAction(nsAtom& aProperty,
       MOZ_ASSERT(!EmptyString().IsVoid());
       editActionData.SetData(EmptyString());
       break;
+    case EditAction::eRemoveColorProperty:
+    case EditAction::eRemoveBackgroundColorPropertyInline:
+      editActionData.SetColorData(EmptyString());
+      break;
     default:
       break;
   }
@@ -1273,6 +1285,10 @@ HTMLEditor::RemoveInlineProperty(const nsAString& aProperty,
       MOZ_ASSERT(!EmptyString().IsVoid());
       editActionData.SetData(EmptyString());
       break;
+    case EditAction::eRemoveColorProperty:
+    case EditAction::eRemoveBackgroundColorPropertyInline:
+      editActionData.SetColorData(EmptyString());
+      break;
     default:
       break;
   }

layout/style/nsComputedDOMStyle.cpp

@@ -1021,23 +1021,7 @@ already_AddRefed<CSSValue> nsComputedDOMStyle::DoGetBottom() {
 /* static */ void nsComputedDOMStyle::SetToRGBAColor(
     nsROCSSPrimitiveValue* aValue, nscolor aColor) {
   nsAutoString string;
-  const bool hasAlpha = NS_GET_A(aColor) != 255;
-  if (hasAlpha) {
-    string.AppendLiteral("rgba(");
-  } else {
-    string.AppendLiteral("rgb(");
-  }
-  string.AppendInt(NS_GET_R(aColor));
-  string.AppendLiteral(", ");
-  string.AppendInt(NS_GET_G(aColor));
-  string.AppendLiteral(", ");
-  string.AppendInt(NS_GET_B(aColor));
-  if (hasAlpha) {
-    string.AppendLiteral(", ");
-    float alpha = nsStyleUtil::ColorComponentToFloat(NS_GET_A(aColor));
-    nsStyleUtil::AppendCSSNumber(alpha, string);
-  }
-  string.AppendLiteral(")");
+  nsStyleUtil::GetSerializedColorValue(aColor, string);
   aValue->SetString(string);
 }
 

layout/style/nsStyleUtil.cpp

@@ -269,6 +269,29 @@ void nsStyleUtil::AppendEscapedCSSString(const nsAString& aString,
   return rounded;
 }
 
+/* static */ void nsStyleUtil::GetSerializedColorValue(
+    nscolor aColor, nsAString& aSerializedColor) {
+  MOZ_ASSERT(aSerializedColor.IsEmpty());
+
+  const bool hasAlpha = NS_GET_A(aColor) != 255;
+  if (hasAlpha) {
+    aSerializedColor.AppendLiteral("rgba(");
+  } else {
+    aSerializedColor.AppendLiteral("rgb(");
+  }
+  aSerializedColor.AppendInt(NS_GET_R(aColor));
+  aSerializedColor.AppendLiteral(", ");
+  aSerializedColor.AppendInt(NS_GET_G(aColor));
+  aSerializedColor.AppendLiteral(", ");
+  aSerializedColor.AppendInt(NS_GET_B(aColor));
+  if (hasAlpha) {
+    aSerializedColor.AppendLiteral(", ");
+    float alpha = nsStyleUtil::ColorComponentToFloat(NS_GET_A(aColor));
+    nsStyleUtil::AppendCSSNumber(alpha, aSerializedColor);
+  }
+  aSerializedColor.AppendLiteral(")");
+}
+
 /* static */ bool nsStyleUtil::IsSignificantChild(
     nsIContent* aChild, bool aWhitespaceIsSignificant) {
   bool isText = aChild->IsText();

layout/style/nsStyleUtil.h

@@ -90,6 +90,14 @@ class nsStyleUtil {
    */
   static float ColorComponentToFloat(uint8_t aAlpha);
 
+  /**
+   * GetSerializedColorValue() computes serialized color value of aColor and
+   * returns it with aSerializedColor.
+   * https://drafts.csswg.org/cssom/#serialize-a-css-component-value
+   */
+  static void GetSerializedColorValue(nscolor aColor,
+                                      nsAString& aSerializedColor);
+
   /*
    * Does this child count as significant for selector matching?
    */

widget/EventForwards.h

@@ -164,6 +164,8 @@ inline bool IsDataAvailableOnHTMLEditor(EditorInputType aInputType) {
     case EditorInputType::eFormatSetBlockTextDirection:
     case EditorInputType::eFormatSetInlineTextDirection:
     case EditorInputType::eInsertLink:
+    case EditorInputType::eFormatBackColor:
+    case EditorInputType::eFormatFontColor:
     case EditorInputType::eFormatFontName:
       return true;
     default: