Java tutorial
// 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 com.google.common.base.Preconditions; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableMap; import com.google.devtools.build.lib.cmdline.Label; import com.google.devtools.build.lib.events.Location; import com.google.devtools.build.lib.skylarkinterface.SkylarkPrinter; import com.google.devtools.build.lib.syntax.EvalException; import com.google.devtools.build.lib.syntax.FunctionSignature; import com.google.devtools.build.lib.syntax.SkylarkType; import java.util.Map; import java.util.Objects; import javax.annotation.Nullable; /** * Declared provider defined in Skylark. * * <p>This is a result of calling {@code provider()} function from Skylark ({@link * com.google.devtools.build.lib.analysis.skylark.SkylarkRuleClassFunctions#provider}). */ public class SkylarkProvider extends Provider implements SkylarkExportable { private static final FunctionSignature.WithValues<Object, SkylarkType> SIGNATURE = FunctionSignature.WithValues .create(FunctionSignature.KWARGS); @Nullable private SkylarkKey key; @Nullable private String errorMessageFormatForInstances; private static final String DEFAULT_ERROR_MESSAFE = "Object has no '%s' attribute."; /** * Creates a Skylark-defined Declared Provider ({@link Info} constructor). * * <p>Needs to be exported later. */ public SkylarkProvider(String name, @Nullable Iterable<String> fields, Location location) { this(name, buildSignature(fields), location); } private SkylarkProvider(String name, FunctionSignature.WithValues<Object, SkylarkType> signature, Location location) { super(name, signature, location); this.errorMessageFormatForInstances = DEFAULT_ERROR_MESSAFE; } private static FunctionSignature.WithValues<Object, SkylarkType> buildSignature( @Nullable Iterable<String> fields) { if (fields == null) { return SIGNATURE; } return FunctionSignature.WithValues .create(FunctionSignature.namedOnly(0, ImmutableList.copyOf(fields).toArray(new String[0]))); } @Override protected Info createInstanceFromSkylark(Object[] args, Location loc) throws EvalException { if (signature.getSignature().getShape().hasKwArg()) { @SuppressWarnings("unchecked") Map<String, Object> kwargs = (Map<String, Object>) args[0]; return new SkylarkInfo(this, kwargs, loc); } else { // todo(dslomov): implement shape sharing. ImmutableList<String> names = signature.getSignature().getNames(); Preconditions.checkState(names.size() == args.length); ImmutableMap.Builder<String, Object> fields = ImmutableMap.builder(); for (int i = 0; i < args.length; i++) { if (args[i] != null) { fields.put(names.get(i), args[i]); } } return new SkylarkInfo(this, fields.build(), loc); } } @Override public boolean isExported() { return key != null; } @Override public SkylarkKey getKey() { Preconditions.checkState(isExported()); return key; } @Override public String getName() { return key != null ? key.getExportedName() : "<no name>"; } @Override public String getPrintableName() { return getName(); } @Override public String getErrorMessageFormatForInstances() { return errorMessageFormatForInstances; } @Override public void export(Label extensionLabel, String exportedName) { Preconditions.checkState(!isExported()); this.key = new SkylarkKey(extensionLabel, exportedName); this.errorMessageFormatForInstances = String.format("'%s' object has no attribute '%%s'", exportedName); } @Override public int hashCode() { if (isExported()) { return getKey().hashCode(); } return System.identityHashCode(this); } @Override public boolean equals(@Nullable Object otherObject) { if (!(otherObject instanceof SkylarkProvider)) { return false; } SkylarkProvider other = (SkylarkProvider) otherObject; if (this.isExported() && other.isExported()) { return this.getKey().equals(other.getKey()); } else { return this == other; } } @Override public boolean isImmutable() { // Hash code for non exported constructors may be changed return isExported(); } @Override public void repr(SkylarkPrinter printer) { printer.append("<provider>"); } /** * A serializable representation of Skylark-defined {@link SkylarkProvider} that uniquely * identifies all {@link SkylarkProvider}s that are exposed to SkyFrame. */ public static class SkylarkKey extends Key { private final Label extensionLabel; private final String exportedName; public SkylarkKey(Label extensionLabel, String exportedName) { this.extensionLabel = Preconditions.checkNotNull(extensionLabel); this.exportedName = Preconditions.checkNotNull(exportedName); } public Label getExtensionLabel() { return extensionLabel; } public String getExportedName() { return exportedName; } @Override public String toString() { return exportedName; } @Override public int hashCode() { return Objects.hash(extensionLabel, exportedName); } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (!(obj instanceof SkylarkKey)) { return false; } SkylarkKey other = (SkylarkKey) obj; return Objects.equals(this.extensionLabel, other.extensionLabel) && Objects.equals(this.exportedName, other.exportedName); } } }