com.google.common.css.compiler.passes.CreateStandardAtRuleNodes Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of closure-stylesheets Show documentation
Show all versions of closure-stylesheets Show documentation
Closure Stylesheets is an extension to CSS that adds variables,
functions,
conditionals, and mixins to standard CSS. The tool also supports
minification, linting, RTL flipping, and CSS class renaming.
The newest version!
/*
* Copyright 2009 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.common.css.compiler.passes;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.google.common.css.compiler.ast.CssAtRuleNode;
import com.google.common.css.compiler.ast.CssAtRuleNode.Type;
import com.google.common.css.compiler.ast.CssBlockNode;
import com.google.common.css.compiler.ast.CssBooleanExpressionNode;
import com.google.common.css.compiler.ast.CssCompilerPass;
import com.google.common.css.compiler.ast.CssCompositeValueNode;
import com.google.common.css.compiler.ast.CssConditionalBlockNode;
import com.google.common.css.compiler.ast.CssDeclarationBlockNode;
import com.google.common.css.compiler.ast.CssFontFaceNode;
import com.google.common.css.compiler.ast.CssFunctionNode;
import com.google.common.css.compiler.ast.CssImportBlockNode;
import com.google.common.css.compiler.ast.CssImportRuleNode;
import com.google.common.css.compiler.ast.CssLiteralNode;
import com.google.common.css.compiler.ast.CssMediaRuleNode;
import com.google.common.css.compiler.ast.CssNode;
import com.google.common.css.compiler.ast.CssPageRuleNode;
import com.google.common.css.compiler.ast.CssPageSelectorNode;
import com.google.common.css.compiler.ast.CssRootNode;
import com.google.common.css.compiler.ast.CssRulesetNode;
import com.google.common.css.compiler.ast.CssStringNode;
import com.google.common.css.compiler.ast.CssUnknownAtRuleNode;
import com.google.common.css.compiler.ast.CssValueNode;
import com.google.common.css.compiler.ast.ErrorManager;
import com.google.common.css.compiler.ast.GssError;
import com.google.common.css.compiler.ast.MutatingVisitController;
import java.util.List;
import java.util.Set;
/**
* A compiler pass that transforms standard {@link CssUnknownAtRuleNode} instances
* to more specific at-rule nodes, or deletes them.
*
*/
public class CreateStandardAtRuleNodes extends UniformVisitor implements CssCompilerPass {
@VisibleForTesting
static final String NO_BLOCK_ERROR_MESSAGE =
"This @-rule has to have a block";
@VisibleForTesting
static final String BLOCK_ERROR_MESSAGE =
"This @-rule is not allowed to have a block";
@VisibleForTesting
static final String ONLY_DECLARATION_BLOCK_ERROR_MESSAGE =
"Only declaration blocks are allowed for this @-rule";
@VisibleForTesting
static final String INVALID_PARAMETERS_ERROR_MESSAGE =
"This @-rule has invalid parameters";
@VisibleForTesting
static final String MEDIA_INVALID_CHILD_ERROR_MESSAGE =
"This is not valid inside an @media block";
@VisibleForTesting
static final String MEDIA_WITHOUT_PARAMETERS_ERROR_MESSAGE =
"@media without parameters";
@VisibleForTesting
static final String PAGE_SELECTOR_PARAMETERS_ERROR_MESSAGE =
"Page selectors are not allowed to have parameters";
@VisibleForTesting
static final String FONT_FACE_PARAMETERS_ERROR_MESSAGE =
"@font-face is not allowed to have parameters";
@VisibleForTesting
static final String IGNORED_IMPORT_WARNING_MESSAGE =
"@import rules should occur outside blocks and can only be preceded "
+ "by @charset and other @import rules.";
@VisibleForTesting
static final String IGNORE_IMPORT_WARNING_MESSAGE =
"A node after which all @import rule nodes are ignored is here.";
private static final List PAGE_SELECTORS =
ImmutableList.of(Type.TOP_LEFT_CORNER,
Type.TOP_LEFT, Type.TOP_CENTER, Type.TOP_RIGHT, Type.TOP_RIGHT_CORNER,
Type.LEFT_TOP, Type.LEFT_MIDDLE, Type.LEFT_BOTTOM, Type.RIGHT_TOP,
Type.RIGHT_MIDDLE, Type.RIGHT_BOTTOM, Type.BOTTOM_LEFT_CORNER,
Type.BOTTOM_LEFT, Type.BOTTOM_CENTER, Type.BOTTOM_RIGHT,
Type.BOTTOM_RIGHT_CORNER);
private static final Set PSEUDO_PAGES = ImmutableSet.of(
":left", ":right", ":first");
// The @-rules are restricted because it only makes sense for them to be used
// inside an @media block. Especially @def should never be allowed because it
// can be misleading; @def rules are processed by the compiler but @media
// rules are handled by the browser.
private static final Set ALLOWED_AT_RULES_IN_MEDIA = ImmutableSet.of(
"page", "if", "elseif", "else", "for");
private final MutatingVisitController visitController;
private final ErrorManager errorManager;
private final List nonIgnoredImportRules =
Lists.newArrayList();
private CssRootNode root;
/**
* The first node after which import rules will be ignored, or null if
* no such nodes have been discovered.
*/
private CssNode noMoreImportRules;
public CreateStandardAtRuleNodes(MutatingVisitController visitController,
ErrorManager errorManager) {
this.visitController = visitController;
this.errorManager = errorManager;
}
@Override
public boolean enterTree(CssRootNode root) {
this.root = root;
noMoreImportRules = null;
return true;
}
@Override
public void leave(CssNode node) {
if (node instanceof CssImportRuleNode
|| node instanceof CssImportBlockNode
|| node == root.getCharsetRule()) {
return;
}
noMoreImportRules = node;
}
@Override
public boolean enterUnknownAtRule(CssUnknownAtRuleNode node) {
String charsetName = CssAtRuleNode.Type.CHARSET.getCanonicalName();
String importName = CssAtRuleNode.Type.IMPORT.getCanonicalName();
String mediaName = CssAtRuleNode.Type.MEDIA.getCanonicalName();
String pageName = CssAtRuleNode.Type.PAGE.getCanonicalName();
String fontFaceName = CssAtRuleNode.Type.FONT_FACE.getCanonicalName();
List params = node.getParameters();
if (node.getName().getValue().equals(charsetName)) {
// We don't have a specific node class for this, should be handled at the parser level.
// TODO(user): Give a warning instead that the node has been removed without processing. (?)
reportError("@" + charsetName + " removed", node);
return false;
} else if (node.getName().getValue().equals(importName)) {
if (params.isEmpty()) {
reportError("@" + importName + " without a following string or uri", node);
return false;
}
if (params.size() > 2) {
reportError("@" + importName + " with too many parameters", node);
return false;
}
CssValueNode param = params.get(0);
if (!((param instanceof CssStringNode) || checkIfUri(param))) {
reportError("@" + importName + "'s first parameter has to be a string or an url", node);
return false;
}
List paramlist = Lists.newArrayList(param);
if (params.size() == 2) {
CssValueNode param2 = params.get(1);
if (param2 instanceof CssCompositeValueNode || param2 instanceof CssLiteralNode) {
paramlist.add(param2);
} else {
reportError("@" + importName + " has illegal parameter", node);
return false;
}
}
CssImportRuleNode importRule = new CssImportRuleNode(node.getComments());
importRule.setParameters(paramlist);
importRule.setSourceCodeLocation(node.getSourceCodeLocation());
if (noMoreImportRules != null) {
visitController.replaceCurrentBlockChildWith(
Lists.newArrayList((CssNode) importRule),
false /* visitTheReplacementNodes */);
reportWarning(IGNORED_IMPORT_WARNING_MESSAGE, node);
reportWarning(IGNORE_IMPORT_WARNING_MESSAGE, noMoreImportRules);
} else {
visitController.removeCurrentNode();
nonIgnoredImportRules.add(importRule);
}
return false;
} else if (node.getName().getValue().equals(mediaName)) {
createMediaRule(node);
} else if (node.getName().getValue().equals(pageName)) {
createPageRule(node);
} else if (node.getName().getValue().equals(fontFaceName)) {
createFontFaceRule(node);
} else {
for (Type type : PAGE_SELECTORS) {
if (node.getName().getValue().equals(type.getCanonicalName())) {
createPageSelector(type, node);
break;
}
}
}
return true;
}
@Override
public void leaveTree(CssRootNode root) {
for (CssImportRuleNode importRule : nonIgnoredImportRules) {
root.getImportRules().addChildToBack(importRule);
}
}
/**
* See the
* CSS 2.1 syntax
* , and
* CSS 3 syntax
* for more information.
*/
private void createMediaRule(CssUnknownAtRuleNode node) {
if (node.getBlock() == null) {
reportError(NO_BLOCK_ERROR_MESSAGE, node);
return;
}
if (!(node.getBlock() instanceof CssBlockNode)) {
reportError(ONLY_DECLARATION_BLOCK_ERROR_MESSAGE, node);
return;
}
CssBlockNode block = (CssBlockNode) node.getBlock();
for (CssNode part : block.childIterable()) {
if (!isValidInMediaRule(part)) {
reportError(MEDIA_INVALID_CHILD_ERROR_MESSAGE, part);
return;
}
}
List params = node.getParameters();
if (params.isEmpty()) {
reportError(MEDIA_WITHOUT_PARAMETERS_ERROR_MESSAGE, node);
return;
}
// TODO(fbenz): Perform this check depending on the CSS version set in the
// options
if (!checkMediaParameter(params)) {
reportError(INVALID_PARAMETERS_ERROR_MESSAGE, node);
return;
}
CssMediaRuleNode mediaRule = new CssMediaRuleNode(node.getComments(),
block);
mediaRule.setParameters(params);
mediaRule.setSourceCodeLocation(node.getSourceCodeLocation());
visitController.replaceCurrentBlockChildWith(
Lists.newArrayList(mediaRule), true /* visitTheReplacementNodes */);
}
/**
* Checks whether the parameters of a @media rule match the grammar of the
* CSS 3 draft.
*/
private boolean checkMediaParameter(List params) {
if (params.get(0) instanceof CssCompositeValueNode) {
return checkMediaCompositeExpression(params, 0);
} else if (params.get(0) instanceof CssBooleanExpressionNode) {
// shorthand syntax: implicit "all and..."
return checkMediaExpression(params, 0);
} else if (!(params.get(0) instanceof CssLiteralNode)) {
// nodes like the function node are invalid
CssValueNode node = params.get(0);
reportWarning(
String.format(
"Expected CssLiteralNode but found %s",
node.getClass().getName()),
node);
return false;
}
int numberOfStartingLiterals = 1;
String firstValue = params.get(0).getValue();
if (firstValue.equals("only") || firstValue.equals("not")) {
numberOfStartingLiterals = 2;
}
if (params.size() < numberOfStartingLiterals) {
// only 'only' or 'not'
reportWarning(
"Expected CssLiteralNode after 'only' or 'not'.",
params.get(params.size() - 1));
return false;
}
if (params.size() - numberOfStartingLiterals > 0) {
return checkAndMediaExpression(params, numberOfStartingLiterals);
}
return true;
}
/**
* Checks for [ AND S* expression ]* where expression is some value.
*/
private boolean checkAndMediaExpression(
List params, int start) {
if (params.size() - start < 2) {
// at least two more: 'and X'
return false;
}
if (!params.get(start).getValue().equals("and")) {
// expected 'and'
return false;
}
return checkMediaExpression(params, start + 1);
}
/**
* Checks for S* expression | S* expression [ AND S* expression ]*
* where expression is some value.
*/
private boolean checkMediaExpression(
List params, int start) {
if (params.size() - start < 1) {
// at least one
return false;
}
if (params.get(start) instanceof CssCompositeValueNode) {
return checkMediaCompositeExpression(params, start);
} else if (params.size() > start + 1) {
return checkAndMediaExpression(params, start + 1);
}
return true;
}
/**
* Splits up a composite value so that it can be checked. Two values with
* a comma in between are combined to a composite value.
* For example:
* {@code screen and (device-width:800px), print}
* turns into this list of values:
* {@code screen}, {@code and}, {@code (device-width:800px), print}
* where the last value is a composite value that consists of two values.
*/
private boolean checkMediaCompositeExpression(List params,
int start) {
CssCompositeValueNode comp = (CssCompositeValueNode) params.get(start);
CssValueNode startValue;
if (comp.getValues().size() == 2) {
startValue = comp.getValues().get(1);
} else {
List newChildren = Lists.newArrayList(comp.getValues());
newChildren.remove(0);
startValue = new CssCompositeValueNode(newChildren,
comp.getOperator(), comp.getSourceCodeLocation());
}
List newParams = Lists.newArrayList(startValue);
for (int i = 0; i < params.size(); i++) {
if (i > start) {
newParams.add(params.get(i));
}
}
return checkMediaParameter(newParams);
}
private boolean isValidInMediaRule(CssNode node) {
if (node instanceof CssRulesetNode) {
// rulesets like .CLASS { ... }
return true;
}
if (node instanceof CssAtRuleNode && ALLOWED_AT_RULES_IN_MEDIA.contains(
((CssAtRuleNode) node).getName().getValue())) {
// like @page or @if, but not @def
return true;
}
if (node instanceof CssConditionalBlockNode) {
// @if, @elseif, @else after processing because then they are not @-rules
// anymore
return true;
}
return false;
}
/**
* See the
*
* Page selector grammar for more information.
*/
private void createPageRule(CssUnknownAtRuleNode node) {
if (node.getBlock() == null) {
reportError(NO_BLOCK_ERROR_MESSAGE, node);
return;
}
if (!(node.getBlock() instanceof CssDeclarationBlockNode)) {
reportError(ONLY_DECLARATION_BLOCK_ERROR_MESSAGE, node);
return;
}
List params = node.getParameters();
int numParams = params.size();
if (numParams > 2) {
reportError(INVALID_PARAMETERS_ERROR_MESSAGE, node);
return;
} else if (numParams == 2
&& !PSEUDO_PAGES.contains(params.get(1).getValue())) {
reportError(INVALID_PARAMETERS_ERROR_MESSAGE, node);
return;
} else if (numParams == 1) {
if (params.get(0).getValue().startsWith(":")
&& !PSEUDO_PAGES.contains(params.get(0).getValue())) {
reportError(INVALID_PARAMETERS_ERROR_MESSAGE, node);
return;
}
}
CssDeclarationBlockNode block = (CssDeclarationBlockNode) node.getBlock();
CssPageRuleNode pageRule = new CssPageRuleNode(node.getComments(),
block);
pageRule.setParameters(params);
pageRule.setSourceCodeLocation(node.getSourceCodeLocation());
visitController.replaceCurrentBlockChildWith(
Lists.newArrayList(pageRule), true /* visitTheReplacementNodes */);
}
private void createPageSelector(Type type, CssUnknownAtRuleNode node) {
if (node.getBlock() == null) {
reportError(NO_BLOCK_ERROR_MESSAGE, node);
return;
}
if (!(node.getBlock() instanceof CssDeclarationBlockNode)) {
reportError(ONLY_DECLARATION_BLOCK_ERROR_MESSAGE, node);
return;
}
if (!node.getParameters().isEmpty()) {
reportError(PAGE_SELECTOR_PARAMETERS_ERROR_MESSAGE, node);
return;
}
CssDeclarationBlockNode block = (CssDeclarationBlockNode) node.getBlock();
CssPageSelectorNode pageSelector = new CssPageSelectorNode(type,
node.getComments(), block);
pageSelector.setSourceCodeLocation(node.getSourceCodeLocation());
visitController.replaceCurrentBlockChildWith(
Lists.newArrayList(pageSelector), true /* visitTheReplacementNodes */);
}
/**
* See the
*
* font-face grammar for more information.
*/
private void createFontFaceRule(CssUnknownAtRuleNode node) {
if (node.getBlock() == null) {
reportError(NO_BLOCK_ERROR_MESSAGE, node);
return;
}
if (!(node.getBlock() instanceof CssDeclarationBlockNode)) {
reportError(ONLY_DECLARATION_BLOCK_ERROR_MESSAGE, node);
return;
}
if (!node.getParameters().isEmpty()) {
reportError(FONT_FACE_PARAMETERS_ERROR_MESSAGE, node);
return;
}
// TODO(bolinfest): Verify that all declarations in the block are valid
// font-descriptions: font-family, src, font-style, etc. See
// http://www.w3.org/TR/css3-fonts/#font-resources for a complete list.
CssDeclarationBlockNode block = (CssDeclarationBlockNode) node.getBlock();
CssFontFaceNode fontFace = new CssFontFaceNode(node.getComments(), block);
fontFace.setSourceCodeLocation(node.getSourceCodeLocation());
visitController.replaceCurrentBlockChildWith(
Lists.newArrayList(fontFace), true /* visitTheReplacementNodes */);
}
private boolean checkIfUri(CssValueNode node) {
if (!(node instanceof CssFunctionNode)) {
return false;
}
CssFunctionNode function = (CssFunctionNode) node;
if (function.getFunctionName().toLowerCase().equals("url")) {
return true;
}
return false;
}
private void reportError(String message, CssNode node) {
errorManager.report(new GssError(message, node.getSourceCodeLocation()));
visitController.removeCurrentNode();
}
private void reportWarning(String message, CssNode node) {
errorManager.reportWarning(
new GssError(message, node.getSourceCodeLocation()));
}
@Override
public void runPass() {
visitController.startVisit(this);
}
}