Added CSSPropertyBackgroundComponentUtils which holds background component parsing methods.

third_party/WebKit/Source/core/css/properties/CSSPropertyBackgroundComponentUtils.cpp

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/css/properties/CSSPropertyBackgroundComponentUtils.h"
+
+#include "core/css/CSSValueList.h"
+#include "core/css/CSSValuePair.h"
+#include "core/css/parser/CSSPropertyParserHelpers.h"
+#include "core/css/properties/CSSPropertyPositionUtils.h"
+#include "platform/RuntimeEnabledFeatures.h"
+
+namespace blink {
+
+namespace {
+
+static CSSValue* consumeBackgroundBlendMode(CSSParserTokenRange& range) {
+  CSSValueID id = range.peek().id();
+  if (id == CSSValueNormal || id == CSSValueOverlay ||
+      (id >= CSSValueMultiply && id <= CSSValueLuminosity))
+    return CSSPropertyParserHelpers::consumeIdent(range);
+  return nullptr;
+}
+
+CSSValue* consumeBackgroundAttachment(CSSParserTokenRange& range) {
+  return CSSPropertyParserHelpers::consumeIdent<CSSValueScroll, CSSValueFixed,
+                                                CSSValueLocal>(range);
+}
+
+CSSValue* consumeBackgroundBox(CSSParserTokenRange& range) {
+  return CSSPropertyParserHelpers::consumeIdent<
+      CSSValueBorderBox, CSSValuePaddingBox, CSSValueContentBox>(range);
+}
+
+CSSValue* consumeBackgroundComposite(CSSParserTokenRange& range) {
+  return CSSPropertyParserHelpers::consumeIdentRange(range, CSSValueClear,
+                                                     CSSValuePlusLighter);
+}
+
+CSSValue* consumeMaskSourceType(CSSParserTokenRange& range) {
+  DCHECK(RuntimeEnabledFeatures::cssMaskSourceTypeEnabled());
+  return CSSPropertyParserHelpers::consumeIdent<CSSValueAuto, CSSValueAlpha,
+                                                CSSValueLuminance>(range);
+}
+
+CSSValue* consumePrefixedBackgroundBox(CSSPropertyID property,
+                                       CSSParserTokenRange& range,
+                                       const CSSParserContext* context) {
+  // The values 'border', 'padding' and 'content' are deprecated and do not
+  // apply to the version of the property that has the -webkit- prefix removed.
+  if (CSSValue* value = CSSPropertyParserHelpers::consumeIdentRange(
+          range, CSSValueBorder, CSSValuePaddingBox))
+    return value;
+  if ((property == CSSPropertyWebkitBackgroundClip ||
+       property == CSSPropertyWebkitMaskClip) &&
+      range.peek().id() == CSSValueText)
+    return CSSPropertyParserHelpers::consumeIdent(range);
+  return nullptr;
+}
+
+}  // namespace
+
+CSSValue* CSSPropertyBackgroundComponentUtils::consumeBackgroundSize(
+    CSSPropertyID unresolvedProperty,
+    CSSParserTokenRange& range,
+    CSSParserMode cssParserMode) {
+  if (CSSPropertyParserHelpers::identMatches<CSSValueContain, CSSValueCover>(
+          range.peek().id()))
+    return CSSPropertyParserHelpers::consumeIdent(range);
+
+  CSSValue* horizontal =
+      CSSPropertyParserHelpers::consumeIdent<CSSValueAuto>(range);
+  if (!horizontal) {
+    horizontal = CSSPropertyParserHelpers::consumeLengthOrPercent(
+        range, cssParserMode, ValueRangeAll,
+        CSSPropertyParserHelpers::UnitlessQuirk::Forbid);
+  }
+
+  CSSValue* vertical = nullptr;
+  if (!range.atEnd()) {
+    if (range.peek().id() == CSSValueAuto) {
+      // `auto' is the default
+      range.consumeIncludingWhitespace();
+    } else {
+      vertical = CSSPropertyParserHelpers::consumeLengthOrPercent(
+          range, cssParserMode, ValueRangeAll,
+          CSSPropertyParserHelpers::UnitlessQuirk::Forbid);
+    }
+  } else if (unresolvedProperty == CSSPropertyAliasWebkitBackgroundSize) {
+    // Legacy syntax: "-webkit-background-size: 10px" is equivalent to
+    // "background-size: 10px 10px".
+    vertical = horizontal;
+  }
+  if (!vertical)
+    return horizontal;
+  return CSSValuePair::create(horizontal, vertical,
+                              CSSValuePair::KeepIdenticalValues);
+}
+
+void CSSPropertyBackgroundComponentUtils::addBackgroundValue(CSSValue*& list,
+                                                             CSSValue* value) {
+  if (list) {
+    if (!list->isBaseValueList()) {
+      CSSValue* firstValue = list;
+      list = CSSValueList::createCommaSeparated();
+      toCSSValueList(list)->append(*firstValue);
+    }
+    toCSSValueList(list)->append(*value);
+  } else {
+    // To conserve memory we don't actually wrap a single value in a list.
+    list = value;
+  }
+}
+
+CSSValue* CSSPropertyBackgroundComponentUtils::consumeBackgroundComponent(
+    CSSPropertyID unresolvedProperty,
+    CSSParserTokenRange& range,
+    const CSSParserContext* context) {
+  switch (unresolvedProperty) {
+    case CSSPropertyBackgroundClip:
+      return consumeBackgroundBox(range);
+    case CSSPropertyBackgroundBlendMode:
+      return consumeBackgroundBlendMode(range);
+    case CSSPropertyBackgroundAttachment:
+      return consumeBackgroundAttachment(range);
+    case CSSPropertyBackgroundOrigin:
+      return consumeBackgroundBox(range);
+    case CSSPropertyWebkitMaskComposite:
+      return consumeBackgroundComposite(range);
+    case CSSPropertyMaskSourceType:
+      return consumeMaskSourceType(range);
+    case CSSPropertyWebkitBackgroundClip:
+    case CSSPropertyWebkitBackgroundOrigin:
+    case CSSPropertyWebkitMaskClip:
+    case CSSPropertyWebkitMaskOrigin:
+      return consumePrefixedBackgroundBox(unresolvedProperty, range, context);
+    case CSSPropertyBackgroundImage:
+    case CSSPropertyWebkitMaskImage:
+      return CSSPropertyParserHelpers::consumeImageOrNone(range, context);
+    case CSSPropertyBackgroundPositionX:
+    case CSSPropertyWebkitMaskPositionX:
+      return CSSPropertyPositionUtils::consumePositionLonghand<CSSValueLeft,
+                                                               CSSValueRight>(
+          range, context->mode());
+    case CSSPropertyBackgroundPositionY:
+    case CSSPropertyWebkitMaskPositionY:
+      return CSSPropertyPositionUtils::consumePositionLonghand<CSSValueTop,
+                                                               CSSValueBottom>(
+          range, context->mode());
+    case CSSPropertyBackgroundSize:
+    case CSSPropertyAliasWebkitBackgroundSize:
+    case CSSPropertyWebkitMaskSize:
+      return consumeBackgroundSize(unresolvedProperty, range, context->mode());
+    case CSSPropertyBackgroundColor:
+      return CSSPropertyParserHelpers::consumeColor(range, context->mode());
+    default:
+      break;
+  };
+  return nullptr;
+}
+
+}  // namespace blink