// 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.analysis; import com.google.common.base.Supplier; import com.google.common.base.Suppliers; import com.google.common.collect.ImmutableCollection; import com.google.common.collect.ImmutableMap; import com.google.devtools.build.lib.actions.Artifact; import com.google.devtools.build.lib.analysis.stringtemplate.ExpansionException; import com.google.devtools.build.lib.analysis.stringtemplate.TemplateContext; import com.google.devtools.build.lib.cmdline.Label; import java.util.Collection; import java.util.Map; import java.util.function.Function; import javax.annotation.Nullable; /** * Expands $(location) and $(locations) tags inside target attributes. You can specify something * like this in the BUILD file: * *
 * somerule(name='some name',
 *          someopt = [ '$(location //mypackage:myhelper)' ],
 *          ...)
 * 
* * and location will be substituted with //mypackage:myhelper executable output. * *

Note that this expander will always expand labels in srcs, deps, and tools attributes, with * data being optional. * *

DO NOT USE DIRECTLY! Use RuleContext.getExpander() instead. */ final class LocationTemplateContext implements TemplateContext { private final TemplateContext delegate; private final ImmutableMap> functions; private LocationTemplateContext( TemplateContext delegate, Label root, Supplier>> locationMap, boolean execPaths) { this.delegate = delegate; this.functions = LocationExpander.allLocationFunctions(root, locationMap, execPaths); } public LocationTemplateContext( TemplateContext delegate, RuleContext ruleContext, @Nullable ImmutableMap> labelMap, boolean execPaths, boolean allowData) { this( delegate, ruleContext.getLabel(), // Use a memoizing supplier to avoid eagerly building the location map. Suppliers.memoize( () -> LocationExpander.buildLocationMap(ruleContext, labelMap, allowData)), execPaths); } @Override public String lookupVariable(String name) throws ExpansionException { return delegate.lookupVariable(name); } @Override public String lookupFunction(String name, String param) throws ExpansionException { try { Function f = functions.get(name); if (f != null) { return f.apply(param); } } catch (IllegalStateException e) { throw new ExpansionException(e.getMessage(), e); } return delegate.lookupFunction(name, param); } }