com.google.common.css.compiler.passes.ResolveCustomFunctionNodes Maven / Gradle / Ivy
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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.
/*
* 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.base.Preconditions;
import com.google.common.base.Throwables;
import com.google.common.collect.ImmutableSet;
import com.google.common.css.compiler.ast.*;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* This compiler pass replaces {@link CssCustomFunctionNode} instances with the
* list of nodes returned by the GssFunction.
*/
public class ResolveCustomFunctionNodes extends DefaultTreeVisitor
implements CssCompilerPass {
private final MutatingVisitController visitController;
protected final Map functionMap;
private final ErrorManager errorManager;
private final boolean allowUnknownFunctions;
private final Set allowedNonStandardFunctions;
/**
* Constructs the pass.
*
* @param visitController The visit controller
* @param errorManager The error manager
* @param functionMap The map from function names to resolve to GSS functions
*/
public ResolveCustomFunctionNodes(MutatingVisitController visitController,
ErrorManager errorManager,
Map functionMap) {
this(visitController, errorManager, functionMap,
false /* allowUnknownFunctions */);
}
/**
* Constructs the pass.
*
* @param visitController The visit controller
* @param errorManager The error manager
* @param functionMap The map from function names to resolve to GSS functions
* @param allowUnknownFunctions Whether to allow unknown function calls,
* leaving them as is, instead of reporting an error
*/
public ResolveCustomFunctionNodes(MutatingVisitController visitController,
ErrorManager errorManager,
Map functionMap,
boolean allowUnknownFunctions) {
this(visitController, errorManager, functionMap, allowUnknownFunctions,
ImmutableSet.of() /* allowedNonStandardFunctions */);
}
/**
* Constructs the pass.
*
* @param visitController The visit controller
* @param errorManager The error manager
* @param functionMap The map from function names to resolve to GSS functions
* @param allowUnknownFunctions Whether to allow unknown function calls,
* leaving them as is, instead of reporting an error
* @param allowedNonStandardFunctions functions that should not yield a
* warning if they appear in a stylesheet
*/
public ResolveCustomFunctionNodes(MutatingVisitController visitController,
ErrorManager errorManager,
Map functionMap,
boolean allowUnknownFunctions,
Set allowedNonStandardFunctions) {
Preconditions.checkNotNull(functionMap);
this.visitController = visitController;
this.errorManager = errorManager;
this.functionMap = functionMap;
this.allowUnknownFunctions = allowUnknownFunctions;
this.allowedNonStandardFunctions = ImmutableSet.copyOf(
allowedNonStandardFunctions);
}
@Override
public void leaveFunctionNode(CssFunctionNode functionNode) {
if (!(functionNode instanceof Proxiable)) {
return;
}
CssCustomFunctionNode node = (CssCustomFunctionNode) functionNode;
List functionResult = node.getResult();
if (functionResult == null) {
// Look up the function's name in the map.
String functionName = node.getFunctionName();
GssFunction function = functionMap.get(functionName);
if (function == null) {
if (!allowUnknownFunctions && !allowedNonStandardFunctions.contains(
functionName)) {
errorManager.report(new GssError(
String.format("Unknown function \"%s\"", functionName),
node.getSourceCodeLocation()));
visitController.removeCurrentNode();
}
return;
}
List arguments =
CssCustomFunctionNode.fixupFunctionArguments(node.getArguments().childIterable());
Integer expArgNumber = function.getNumExpectedArguments();
int argNumber = arguments.size();
if (expArgNumber != null && expArgNumber != argNumber) {
errorManager.report(new GssError("Function expects " + expArgNumber
+ " arguments but has " + argNumber,
node.getSourceCodeLocation()));
visitController.removeCurrentNode();
return;
}
try {
functionResult = evaluateFunction(node, function, arguments, errorManager);
} catch (GssFunctionException e) {
visitController.removeCurrentNode();
return;
} catch (RuntimeException e) {
errorManager.report(
new GssError(
Throwables.getStackTraceAsString(e),
node.getSourceCodeLocation()));
visitController.removeCurrentNode();
return;
}
}
visitController.replaceCurrentBlockChildWith(functionResult, false);
}
/**
* Evaluates the given function node.
*
* Subclasses may sublcass this method to change the evaluation
* process in some circumstances.
*
* @param node the function node to evaluate
* @param function the GSS function matching this node
* @param arguments the arguments of this node
* @param errorManager the error manager passed into the GSS function call
* @return the result of the evaluation as a list of value nodes
* @throws GssFunctionException if the function call is invalid
* @throws RuntimeException if the function call fails to complete
*/
protected List evaluateFunction(
CssCustomFunctionNode node,
GssFunction function,
List arguments,
ErrorManager errorManager) throws GssFunctionException {
List functionResult =
function.getCallResultNodes(arguments, errorManager);
node.setResult(functionResult);
return functionResult;
}
@Override
public void runPass() {
visitController.startVisit(this);
}
}