| // Copyright 2018 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.concurrent.ThreadSafety.Immutable; |
| import com.google.devtools.build.lib.events.Location; |
| import com.google.devtools.build.lib.syntax.BaseFunction; |
| import com.google.devtools.build.lib.syntax.Environment; |
| import com.google.devtools.build.lib.syntax.EvalException; |
| import com.google.devtools.build.lib.syntax.FuncallExpression; |
| import com.google.devtools.build.lib.syntax.FunctionSignature; |
| import com.google.devtools.build.lib.syntax.SkylarkType; |
| import javax.annotation.Nullable; |
| |
| /** |
| * Implementation of {@link Provider} that is represented by a {@link BaseFunction}, and thus |
| * callable from Skylark. |
| */ |
| @Immutable |
| abstract class ProviderFromFunction extends BaseFunction implements Provider { |
| |
| /** |
| * Constructs a provider. |
| * |
| * @param name provider name; should be null iff the subclass overrides {@link #getName} |
| * @param signature the signature for calling this provider as a Skylark function (to construct an |
| * instance of the provider) |
| * @param location the location of this provider's Skylark definition. Use {@link |
| * Location#BUILTIN} if it is a native provider. |
| */ |
| protected ProviderFromFunction( |
| @Nullable String name, |
| FunctionSignature.WithValues<Object, SkylarkType> signature, |
| Location location) { |
| super(name, signature, location); |
| } |
| |
| public SkylarkProviderIdentifier id() { |
| return SkylarkProviderIdentifier.forKey(getKey()); |
| } |
| |
| @Override |
| protected Object call(Object[] args, @Nullable FuncallExpression ast, Environment env) |
| throws EvalException, InterruptedException { |
| Location loc = ast != null ? ast.getLocation() : Location.BUILTIN; |
| return createInstanceFromSkylark(args, env, loc); |
| } |
| |
| /** |
| * Override this method to provide logic that is used to instantiate a declared provider from |
| * Skylark. |
| * |
| * <p>This is a method that is called when a constructor {@code c} is invoked as<br> |
| * {@code c(arg1 = val1, arg2 = val2, ...)}. |
| * |
| * @param args an array of argument values sorted as per the signature ({@see BaseFunction#call}) |
| */ |
| protected abstract InfoInterface createInstanceFromSkylark( |
| Object[] args, Environment env, Location loc) throws EvalException; |
| } |