| // Copyright 2017 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.rules.python; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.devtools.build.lib.analysis.config.BuildOptions; |
| import com.google.devtools.build.lib.analysis.config.transitions.PatchTransition; |
| import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec; |
| |
| /** A configuration transition that sets the Python version. */ |
| @AutoCodec |
| public class PythonVersionTransition implements PatchTransition { |
| |
| private final PythonVersion version; |
| |
| /** |
| * Creates a new transition that sets the version to the given value, if transitioning is allowed. |
| * |
| * <p>See {@link PythonOptions#canTransitionPythonVersion} for information on when transitioning |
| * is allowed. |
| * |
| * <p>{@code version} must be a target version (either {@code PY2} or {@code PY3}), or else null, |
| * which means use the default value ({@link PythonVersion#DEFAULT_TARGET_VALUE}). |
| * |
| * @throws IllegalArgumentException if {@code version} is non-null and not {@code PY2} or {@code |
| * PY3} |
| */ |
| PythonVersionTransition(PythonVersion version) { |
| if (version == null) { |
| version = PythonVersion.DEFAULT_TARGET_VALUE; |
| } |
| Preconditions.checkArgument(version.isTargetValue()); |
| this.version = version; |
| } |
| |
| @Override |
| public BuildOptions patch(BuildOptions options) { |
| PythonOptions opts = options.get(PythonOptions.class); |
| if (!opts.canTransitionPythonVersion(version)) { |
| return options; |
| } |
| BuildOptions newOptions = options.clone(); |
| PythonOptions newOpts = newOptions.get(PythonOptions.class); |
| newOpts.setPythonVersion(version); |
| return newOptions; |
| } |
| } |