| /* |
| * Copyright (C) 2013 Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "config.h" |
| #include "core/html/parser/HTMLSrcsetParser.h" |
| |
| #include "core/html/parser/HTMLParserIdioms.h" |
| #include "core/platform/ParsingUtilities.h" |
| |
| namespace WebCore { |
| |
| static bool compareByScaleFactor(const ImageCandidate& first, const ImageCandidate& second) |
| { |
| return first.scaleFactor() < second.scaleFactor(); |
| } |
| |
| template<typename CharType> |
| inline bool isComma(CharType character) |
| { |
| return character == ','; |
| } |
| |
| template<typename CharType> |
| static bool parseDescriptors(const CharType* descriptorsStart, const CharType* descriptorsEnd, float& imgScaleFactor) |
| { |
| const CharType* position = descriptorsStart; |
| bool isValid = true; |
| bool isScaleFactorFound = false; |
| while (position < descriptorsEnd) { |
| // 13.1. Let descriptor list be the result of splitting unparsed descriptors on spaces. |
| skipWhile<CharType, isHTMLSpace<CharType> >(position, descriptorsEnd); |
| const CharType* currentDescriptorStart = position; |
| skipWhile<CharType, isNotHTMLSpace<CharType> >(position, descriptorsEnd); |
| const CharType* currentDescriptorEnd = position; |
| |
| ++position; |
| ASSERT(currentDescriptorEnd > currentDescriptorStart); |
| --currentDescriptorEnd; |
| unsigned descriptorLength = currentDescriptorEnd - currentDescriptorStart; |
| if (*currentDescriptorEnd == 'x') { |
| if (isScaleFactorFound) |
| return false; |
| imgScaleFactor = charactersToFloat(currentDescriptorStart, descriptorLength, &isValid); |
| isScaleFactorFound = true; |
| } else { |
| continue; |
| } |
| } |
| return isValid; |
| } |
| |
| // http://www.whatwg.org/specs/web-apps/current-work/multipage/embedded-content-1.html#processing-the-image-candidates |
| template<typename CharType> |
| static void parseImageCandidatesFromSrcsetAttribute(const String& attribute, const CharType* attributeStart, unsigned length, Vector<ImageCandidate>& imageCandidates) |
| { |
| const CharType* position = attributeStart; |
| const CharType* attributeEnd = position + length; |
| |
| while (position < attributeEnd) { |
| float imgScaleFactor = 1.0; |
| |
| // 4. Splitting loop: Skip whitespace. |
| skipWhile<CharType, isHTMLSpace<CharType> >(position, attributeEnd); |
| if (position == attributeEnd) |
| break; |
| const CharType* imageURLStart = position; |
| |
| // If The current candidate is either totally empty or only contains space, skipping. |
| if (*position == ',') { |
| ++position; |
| continue; |
| } |
| |
| // 5. Collect a sequence of characters that are not space characters, and let that be url. |
| skipUntil<CharType, isHTMLSpace<CharType> >(position, attributeEnd); |
| const CharType* imageURLEnd = position; |
| |
| if (position != attributeEnd && *(position - 1) == ',') { |
| --imageURLEnd; |
| } else { |
| // 7. Collect a sequence of characters that are not "," (U+002C) characters, and let that be descriptors. |
| skipWhile<CharType, isHTMLSpace<CharType> >(position, attributeEnd); |
| const CharType* descriptorsStart = position; |
| skipUntil<CharType, isComma<CharType> >(position, attributeEnd); |
| const CharType* descriptorsEnd = position; |
| if (!parseDescriptors(descriptorsStart, descriptorsEnd, imgScaleFactor)) |
| continue; |
| } |
| |
| imageCandidates.append(ImageCandidate(attribute, imageURLStart - attributeStart, imageURLEnd - imageURLStart, imgScaleFactor)); |
| // 11. Return to the step labeled splitting loop. |
| } |
| } |
| |
| static void parseImageCandidatesFromSrcsetAttribute(const String& attribute, Vector<ImageCandidate>& imageCandidates) |
| { |
| if (attribute.isNull()) |
| return; |
| |
| if (attribute.is8Bit()) |
| parseImageCandidatesFromSrcsetAttribute<LChar>(attribute, attribute.characters8(), attribute.length(), imageCandidates); |
| else |
| parseImageCandidatesFromSrcsetAttribute<UChar>(attribute, attribute.characters16(), attribute.length(), imageCandidates); |
| } |
| |
| static ImageCandidate pickBestImageCandidate(float deviceScaleFactor, Vector<ImageCandidate>& imageCandidates) |
| { |
| if (imageCandidates.isEmpty()) |
| return ImageCandidate(); |
| |
| std::stable_sort(imageCandidates.begin(), imageCandidates.end(), compareByScaleFactor); |
| |
| unsigned i; |
| for (i = 0; i < imageCandidates.size() - 1; ++i) { |
| if (imageCandidates[i].scaleFactor() >= deviceScaleFactor) |
| break; |
| } |
| return imageCandidates[i]; |
| } |
| |
| ImageCandidate bestFitSourceForSrcsetAttribute(float deviceScaleFactor, const String& srcsetAttribute) |
| { |
| Vector<ImageCandidate> imageCandidates; |
| |
| parseImageCandidatesFromSrcsetAttribute(srcsetAttribute, imageCandidates); |
| |
| return pickBestImageCandidate(deviceScaleFactor, imageCandidates); |
| } |
| |
| ImageCandidate bestFitSourceForImageAttributes(float deviceScaleFactor, const String& srcAttribute, const String& srcsetAttribute) |
| { |
| if (srcsetAttribute.isNull()) { |
| if (srcAttribute.isNull()) |
| return ImageCandidate(); |
| return ImageCandidate(srcAttribute, 0, srcAttribute.length(), 1); |
| } |
| |
| Vector<ImageCandidate> imageCandidates; |
| |
| parseImageCandidatesFromSrcsetAttribute(srcsetAttribute, imageCandidates); |
| |
| if (!srcAttribute.isEmpty()) |
| imageCandidates.append(ImageCandidate(srcAttribute, 0, srcAttribute.length(), 1.0)); |
| |
| return pickBestImageCandidate(deviceScaleFactor, imageCandidates); |
| } |
| |
| String bestFitSourceForImageAttributes(float deviceScaleFactor, const String& srcAttribute, ImageCandidate& srcsetImageCandidate) |
| { |
| if (srcsetImageCandidate.isEmpty()) |
| return srcAttribute; |
| |
| Vector<ImageCandidate> imageCandidates; |
| imageCandidates.append(srcsetImageCandidate); |
| |
| if (!srcAttribute.isEmpty()) |
| imageCandidates.append(ImageCandidate(srcAttribute, 0, srcAttribute.length(), 1.0)); |
| |
| return pickBestImageCandidate(deviceScaleFactor, imageCandidates).toString(); |
| } |
| |
| } |