diff options
author | Han-Wen Nienhuys <hanwen@google.com> | 2015-02-25 16:45:20 +0100 |
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committer | Han-Wen Nienhuys <hanwen@google.com> | 2015-02-25 16:45:20 +0100 |
commit | d08b27fa9701fecfdb69e1b0d1ac2459efc2129b (patch) | |
tree | 5d50963026239ca5aebfb47ea5b8db7e814e57c8 /src/main/java/com/google/devtools/build/lib/packages/NonconfigurableAttributeMapper.java |
Update from Google.
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MOE_MIGRATED_REVID=85702957
Diffstat (limited to 'src/main/java/com/google/devtools/build/lib/packages/NonconfigurableAttributeMapper.java')
-rw-r--r-- | src/main/java/com/google/devtools/build/lib/packages/NonconfigurableAttributeMapper.java | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/packages/NonconfigurableAttributeMapper.java b/src/main/java/com/google/devtools/build/lib/packages/NonconfigurableAttributeMapper.java new file mode 100644 index 0000000000..d54c847318 --- /dev/null +++ b/src/main/java/com/google/devtools/build/lib/packages/NonconfigurableAttributeMapper.java @@ -0,0 +1,56 @@ +// Copyright 2014 Google Inc. 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.common.base.Preconditions; +import com.google.common.collect.ImmutableList; + +/** + * {@link AttributeMap} implementation that triggers an {@link IllegalStateException} if called + * on any attribute that supports configurable values, as determined by + * {@link Attribute#isConfigurable()}. + * + * <p>This is particularly useful for logic that doesn't have access to configurations - it + * protects against undefined behavior in response to unexpected configuration-dependent inputs. + */ +public class NonconfigurableAttributeMapper extends AbstractAttributeMapper { + private NonconfigurableAttributeMapper(Rule rule) { + super(rule.getPackage(), rule.getRuleClassObject(), rule.getLabel(), + rule.getAttributeContainer()); + } + + /** + * Example usage: + * + * <pre> + * Label fooLabel = NonconfigurableAttributeMapper.of(rule).get("foo", Type.LABEL); + * </pre> + */ + public static NonconfigurableAttributeMapper of (Rule rule) { + return new NonconfigurableAttributeMapper(rule); + } + + @Override + public <T> T get(String attributeName, Type<T> type) { + Preconditions.checkState(!getAttributeDefinition(attributeName).isConfigurable(), + "Attribute '" + attributeName + "' is potentially configurable - not allowed here"); + return super.get(attributeName, type); + } + + @Override + protected <T> Iterable<T> visitAttribute(String attributeName, Type<T> type) { + T value = get(attributeName, type); + return value == null ? ImmutableList.<T>of() : ImmutableList.of(value); + } +} |