| // Copyright 2016 The Bazel Authors. All rights reserved. |
| // |
| // 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.devtools.build.lib.packages; |
| |
| import com.google.devtools.build.lib.events.Location; |
| import com.google.devtools.build.lib.syntax.EvalException; |
| |
| /** |
| * An enum that represents different types of rule attributes, based on where their values come |
| * from. |
| */ |
| public enum AttributeValueSource { |
| COMPUTED_DEFAULT("$", true), |
| LATE_BOUND(":", true), |
| DIRECT("$", false); |
| |
| private static final String SKYLARK_PREFIX = "_"; |
| |
| private final String nativePrefix; |
| private final boolean mustHaveSkylarkPrefix; |
| |
| /** |
| * Creates a new instance and defines the prefixes for both Skylark and native. |
| * |
| * @param nativePrefix The prefix when converted to a native attribute name. |
| * @param mustHaveSkylarkPrefix Whether the Skylark name must start with {@link |
| * AttributeValueSource#SKYLARK_PREFIX}. |
| */ |
| AttributeValueSource(String nativePrefix, boolean mustHaveSkylarkPrefix) { |
| this.nativePrefix = nativePrefix; |
| this.mustHaveSkylarkPrefix = mustHaveSkylarkPrefix; |
| } |
| |
| /** |
| * Throws an {@link EvalException} if the given Skylark name is not valid for this type. |
| */ |
| public void validateSkylarkName(String attrSkylarkName, Location location) throws EvalException { |
| if (attrSkylarkName.isEmpty()) { |
| throw new EvalException(location, "Attribute name must not be empty."); |
| } |
| |
| if (mustHaveSkylarkPrefix && !attrSkylarkName.startsWith(SKYLARK_PREFIX)) { |
| throw new EvalException( |
| location, |
| String.format( |
| "When an attribute value is a function, the attribute must be private " |
| + "(i.e. start with '%s'). Found '%s'", |
| SKYLARK_PREFIX, attrSkylarkName)); |
| } |
| } |
| |
| /** |
| * Converts the given Skylark attribute name to a native attribute name for this type, or throws |
| * an {@link EvalException} if the given Skylark name is not valid for this type. |
| */ |
| public String convertToNativeName(String attrSkylarkName, Location location) |
| throws EvalException { |
| validateSkylarkName(attrSkylarkName, location); |
| // No need to check for mustHaveSkylarkPrefix since this was already done in |
| // validateSkylarkName(). |
| return attrSkylarkName.startsWith(SKYLARK_PREFIX) |
| ? nativePrefix + attrSkylarkName.substring(SKYLARK_PREFIX.length()) |
| : attrSkylarkName; |
| } |
| } |