/*
* Copyright 2014 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.resources.gss;
import static com.google.gwt.thirdparty.common.css.compiler.passes.PassUtil.ALTERNATE;
import com.google.gwt.core.ext.typeinfo.JClassType;
import com.google.gwt.core.ext.typeinfo.JMethod;
import com.google.gwt.core.ext.typeinfo.JType;
import com.google.gwt.core.ext.typeinfo.NotFoundException;
import com.google.gwt.resources.client.ImageResource;
import com.google.gwt.resources.client.ImageResource.ImageOptions;
import com.google.gwt.resources.client.ImageResource.RepeatStyle;
import com.google.gwt.resources.ext.ResourceContext;
import com.google.gwt.resources.ext.ResourceGeneratorUtil;
import com.google.gwt.resources.gss.ast.CssDotPathNode;
import com.google.gwt.thirdparty.common.css.SourceCodeLocation;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssCommentNode;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssCompilerPass;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssDeclarationNode;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssFunctionArgumentsNode;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssFunctionNode;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssFunctionNode.Function;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssLiteralNode;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssPropertyNode;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssPropertyValueNode;
import com.google.gwt.thirdparty.common.css.compiler.ast.CssValueNode;
import com.google.gwt.thirdparty.common.css.compiler.ast.DefaultTreeVisitor;
import com.google.gwt.thirdparty.common.css.compiler.ast.ErrorManager;
import com.google.gwt.thirdparty.common.css.compiler.ast.GssError;
import com.google.gwt.thirdparty.common.css.compiler.ast.MutatingVisitController;
import com.google.gwt.thirdparty.guava.common.annotations.VisibleForTesting;
import com.google.gwt.thirdparty.guava.common.collect.ImmutableList;
import com.google.gwt.thirdparty.guava.common.collect.ImmutableList.Builder;
import com.google.gwt.thirdparty.guava.common.collect.Lists;
import java.util.List;
/**
* Visitor that detects sprite definitions and replace them by several css rules in order to create
* the corresponding sprited image.
* <p>This visitor will replace the following gss:
* {@code
* .foo {
* padding: 5px;
* gwt-sprite: imageResource;
* width: 150px;
* }
* }
* to the corresponding gss:
* {@code
* .foo {
* padding: 5px;
* /* @alternate */ width: eval("imageResource.getWidth", "px");
* /* @alternate */ height: eval("imageResource.getHeight", "px");
* /* @alternate */ overflow: hidden;
* /* @alternate */ background: resourceUrl("imageResource") eval("imageResource.getLeft",
* "px") eval("imageResource.getTop", "px") no-repeat;
* width: 150px;
* }
* }
* <p>This visitor will also check the presence of the {@link ImageOptions} annotation on the
* image resource in order to support correctly horizontal or vertical repetition.
*/
public class ImageSpriteCreator extends DefaultTreeVisitor implements CssCompilerPass {
@VisibleForTesting
interface MethodByPathHelper {
JMethod getMethodByPath(ResourceContext context, List<String> pathElements,
JType expectedReturnType) throws NotFoundException;
}
private static class MethodByPathHelperImpl implements MethodByPathHelper {
@Override
public JMethod getMethodByPath(ResourceContext context, List<String> pathElements,
JType expectedReturnType) throws NotFoundException {
return ResourceGeneratorUtil.getMethodByPath(context.getClientBundleType(),
pathElements, expectedReturnType);
}
}
private static final String SPRITE_PROPERTY_NAME = "gwt-sprite";
private final MutatingVisitController visitController;
private final ErrorManager errorManager;
private final ResourceContext context;
private final ImageSpriteCreator.MethodByPathHelper methodByPathHelper;
private final JClassType imageResourceType;
private final String resourceThisPrefix;
public ImageSpriteCreator(MutatingVisitController visitController, ResourceContext context,
ErrorManager errorManager) {
this(visitController, context, errorManager, new MethodByPathHelperImpl());
}
@VisibleForTesting
ImageSpriteCreator(MutatingVisitController visitController, ResourceContext context,
ErrorManager errorManager, MethodByPathHelper methodByPathHelper) {
this.visitController = visitController;
this.errorManager = errorManager;
this.context = context;
this.methodByPathHelper = methodByPathHelper;
this.imageResourceType = context.getGeneratorContext().getTypeOracle().findType(
ImageResource.class.getName());
this.resourceThisPrefix = context.getImplementationSimpleSourceName() + ".this";
}
@Override
public boolean enterDeclaration(CssDeclarationNode declaration) {
String propertyName = declaration.getPropertyName().getPropertyName();
if (SPRITE_PROPERTY_NAME.equals(propertyName)) {
createSprite(declaration);
return true;
}
return super.enterDeclaration(declaration);
}
private void createSprite(CssDeclarationNode declaration) {
List<CssValueNode> valuesNodes = declaration.getPropertyValue().getChildren();
if (valuesNodes.size() != 1) {
errorManager.report(new GssError(SPRITE_PROPERTY_NAME + " must have exactly one value",
declaration.getSourceCodeLocation()));
return;
}
String imageResource = valuesNodes.get(0).getValue();
JMethod imageMethod;
try {
imageMethod = methodByPathHelper.getMethodByPath(context, getPathElement(imageResource),
imageResourceType);
} catch (NotFoundException e) {
errorManager.report(new GssError("Unable to find ImageResource method "
+ imageResource + " in " + context.getClientBundleType().getQualifiedSourceName() + " : "
+ e.getMessage(), declaration.getSourceCodeLocation()));
return;
}
ImageOptions options = imageMethod.getAnnotation(ImageOptions.class);
RepeatStyle repeatStyle = options != null ? options.repeatStyle() : RepeatStyle.None;
Builder<CssDeclarationNode> listBuilder = ImmutableList.builder();
SourceCodeLocation sourceCodeLocation = declaration.getSourceCodeLocation();
String repeatText;
switch (repeatStyle) {
case None:
repeatText = " no-repeat";
listBuilder.add(buildHeightDeclaration(imageResource, sourceCodeLocation));
listBuilder.add(buildWidthDeclaration(imageResource, sourceCodeLocation));
break;
case Horizontal:
repeatText = " repeat-x";
listBuilder.add(buildHeightDeclaration(imageResource, sourceCodeLocation));
break;
case Vertical:
repeatText = " repeat-y";
listBuilder.add(buildWidthDeclaration(imageResource, sourceCodeLocation));
break;
case Both:
repeatText = " repeat";
break;
default:
errorManager.report(new GssError("Unknown repeatStyle " + repeatStyle,
sourceCodeLocation));
return;
}
listBuilder.add(buildOverflowDeclaration(sourceCodeLocation));
listBuilder.add(buildBackgroundDeclaration(imageResource, repeatText, sourceCodeLocation));
visitController.replaceCurrentBlockChildWith(listBuilder.build(), false);
}
private CssDeclarationNode buildBackgroundDeclaration(String imageResource, String repeatText,
SourceCodeLocation location) {
// build the url function
CssFunctionNode urlFunction = new CssFunctionNode(Function.byName("url"), location);
CssDotPathNode imageUrl = new CssDotPathNode(resourceThisPrefix, imageResource + ".getSafeUri" +
".asString", null, null, location);
CssFunctionArgumentsNode urlFunctionArguments = new CssFunctionArgumentsNode();
urlFunctionArguments.addChildToBack(imageUrl);
urlFunction.setArguments(urlFunctionArguments);
// build left offset
CssDotPathNode left = new CssDotPathNode(resourceThisPrefix, imageResource + ".getLeft", "-",
"px", location);
// build top offset
CssDotPathNode top = new CssDotPathNode(resourceThisPrefix, imageResource + ".getTop",
"-", "px", location);
// build repeat
CssLiteralNode repeat = new CssLiteralNode(repeatText, location);
CssPropertyNode propertyNode = new CssPropertyNode("background", location);
CssPropertyValueNode propertyValueNode = new CssPropertyValueNode(ImmutableList.of(urlFunction,
left, top, repeat));
propertyValueNode.setSourceCodeLocation(location);
return createDeclarationNode(propertyNode, propertyValueNode, location, true);
}
private CssDeclarationNode buildHeightDeclaration(String imageResource,
SourceCodeLocation location) {
CssPropertyNode propertyNode = new CssPropertyNode("height", location);
CssValueNode valueNode = new CssDotPathNode(resourceThisPrefix, imageResource + ".getHeight",
null, "px", location);
CssPropertyValueNode propertyValueNode = new CssPropertyValueNode(ImmutableList.of(valueNode));
return createDeclarationNode(propertyNode, propertyValueNode, location, true);
}
private CssDeclarationNode buildOverflowDeclaration(SourceCodeLocation location) {
CssPropertyNode propertyNode = new CssPropertyNode("overflow", location);
CssValueNode valueNode = new CssLiteralNode("hidden", location);
CssPropertyValueNode propertyValueNode = new CssPropertyValueNode(ImmutableList.of(valueNode));
return createDeclarationNode(propertyNode, propertyValueNode, location, true);
}
private CssDeclarationNode buildWidthDeclaration(String imageResource,
SourceCodeLocation location) {
CssPropertyNode propertyNode = new CssPropertyNode("width", location);
CssValueNode valueNode = new CssDotPathNode(resourceThisPrefix, imageResource + ".getWidth",
null, "px", location);
CssPropertyValueNode propertyValueNode = new CssPropertyValueNode(ImmutableList.of(valueNode));
return createDeclarationNode(propertyNode, propertyValueNode, location, true);
}
private List<String> getPathElement(String imageResourcePath) {
return Lists.newArrayList(imageResourcePath.split("\\."));
}
private CssDeclarationNode createDeclarationNode(CssPropertyNode propertyNode,
CssPropertyValueNode propertyValueNode, SourceCodeLocation location, boolean useAlternate) {
CssDeclarationNode replaceNode = new CssDeclarationNode(propertyNode, propertyValueNode);
replaceNode.setSourceCodeLocation(location);
if (useAlternate) {
replaceNode.setComments(ImmutableList.of(new CssCommentNode(ALTERNATE, location)));
}
return replaceNode;
}
@Override
public void runPass() {
visitController.startVisit(this);
}
}