blob: 683e02cc1e38af40f41873cb0e5f2d8c2b713037 [file] [log] [blame]
// 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 net.starlark.java.eval.EvalException;
import net.starlark.java.eval.Starlark;
/**
* An enum that represents different types of rule attributes, based on where their values come
* from.
*/
public enum AttributeValueSource {
NATIVE_COMPUTED_DEFAULT("$", false),
COMPUTED_DEFAULT("$", true),
LATE_BOUND(":", true),
DIRECT("$", false);
private static final String STARLARK_PREFIX = "_";
private final String nativePrefix;
private final boolean mustHaveStarlarkPrefix;
/**
* Creates a new instance and defines the prefixes for both Starlark and native.
*
* @param nativePrefix The prefix when converted to a native attribute name.
* @param mustHaveStarlarkPrefix Whether the Starlark name must start with {@link
* AttributeValueSource#STARLARK_PREFIX}.
*/
AttributeValueSource(String nativePrefix, boolean mustHaveStarlarkPrefix) {
this.nativePrefix = nativePrefix;
this.mustHaveStarlarkPrefix = mustHaveStarlarkPrefix;
}
/** Throws an {@link EvalException} if the given Starlark name is not valid for this type. */
public void validateStarlarkName(String attrStarlarkName) throws EvalException {
if (attrStarlarkName.isEmpty()) {
throw new EvalException("Attribute name must not be empty.");
}
if (mustHaveStarlarkPrefix && !attrStarlarkName.startsWith(STARLARK_PREFIX)) {
throw Starlark.errorf(
"When an attribute value is a function, the attribute must be private "
+ "(i.e. start with '%s'). Found '%s'",
STARLARK_PREFIX, attrStarlarkName);
}
}
/**
* Converts the given Starlark attribute name to a native attribute name for this type, or throws
* an {@link EvalException} if the given Starlark name is not valid for this type.
*/
public String convertToNativeName(String attrStarlarkName) throws EvalException {
validateStarlarkName(attrStarlarkName);
// No need to check for mustHaveStarlarkPrefix since this was already done in
// validateStarlarkName().
return attrStarlarkName.startsWith(STARLARK_PREFIX)
? nativePrefix + attrStarlarkName.substring(STARLARK_PREFIX.length())
: attrStarlarkName;
}
}