| // 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.Joiner; |
| import com.google.common.base.Objects; |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.ImmutableCollection; |
| import com.google.common.collect.ImmutableMap; |
| import com.google.common.collect.Ordering; |
| import com.google.devtools.build.lib.events.Location; |
| import com.google.devtools.build.lib.skylarkinterface.SkylarkModule; |
| import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory; |
| import com.google.devtools.build.lib.skylarkinterface.SkylarkPrinter; |
| import com.google.devtools.build.lib.skylarkinterface.SkylarkValue; |
| import com.google.devtools.build.lib.syntax.ClassObject; |
| import com.google.devtools.build.lib.syntax.Environment; |
| import com.google.devtools.build.lib.syntax.EvalException; |
| import com.google.devtools.build.lib.syntax.Printer; |
| import com.google.devtools.build.lib.syntax.SkylarkType; |
| import java.io.Serializable; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Map; |
| import javax.annotation.Nullable; |
| |
| /** An instance (in the Skylark sense, not Java) of a {@link Provider}. */ |
| @SkylarkModule( |
| name = "struct", |
| category = SkylarkModuleCategory.BUILTIN, |
| doc = |
| "A generic object with fields. See the global <a href=\"globals.html#struct\"><code>struct" |
| + "</code></a> function for more details." |
| + "<p>Structs fields cannot be reassigned once the struct is created. Two structs are " |
| + "equal if they have the same fields and if corresponding field values are equal." |
| ) |
| public abstract class Info implements ClassObject, SkylarkValue, Serializable { |
| |
| /** The {@link Provider} that describes the type of this instance. */ |
| private final Provider provider; |
| |
| /** |
| * The Skylark location where this provider instance was created. |
| * |
| * <p>Built-in provider instances may use {@link Location#BUILTIN}. |
| */ |
| private final Location location; |
| |
| /** |
| * Constructs an {@link Info}. |
| * |
| * @param provider the provider describing the type of this instance |
| * @param location the Skylark location where this instance is created. If null, defaults to |
| * {@link Location#BUILTIN}. |
| */ |
| protected Info(Provider provider, @Nullable Location location) { |
| this.provider = Preconditions.checkNotNull(provider); |
| this.location = location == null ? Location.BUILTIN : location; |
| } |
| |
| /** |
| * Preprocesses a map of field values to convert the field names and field values to |
| * Skylark-acceptable names and types. |
| * |
| * <p>This preserves the order of the map entries. |
| */ |
| protected static ImmutableMap<String, Object> copyValues(Map<String, Object> values) { |
| Preconditions.checkNotNull(values); |
| ImmutableMap.Builder<String, Object> builder = ImmutableMap.builder(); |
| for (Map.Entry<String, Object> e : values.entrySet()) { |
| builder.put( |
| Attribute.getSkylarkName(e.getKey()), |
| SkylarkType.convertToSkylark(e.getValue(), (Environment) null)); |
| } |
| return builder.build(); |
| } |
| |
| /** |
| * Returns the Skylark location where this provider instance was created. |
| * |
| * <p>Builtin provider instances may return {@link Location#BUILTIN}. |
| */ |
| public Location getCreationLoc() { |
| return location; |
| } |
| |
| public Provider getProvider() { |
| return provider; |
| } |
| |
| /** |
| * Returns whether the given field name exists. |
| * |
| * <p>This conceptually extends the API for {@link ClassObject}. |
| */ |
| public abstract boolean hasField(String name); |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>Overrides {@link ClassObject#getValue(String)}, but does not allow {@link EvalException} to |
| * be thrown. |
| */ |
| @Nullable |
| @Override |
| public abstract Object getValue(String name); |
| |
| /** |
| * Returns the result of {@link #getValue(String)}, cast as the given type, throwing {@link |
| * EvalException} if the cast fails. |
| */ |
| public <T> T getValue(String key, Class<T> type) throws EvalException { |
| Object obj = getValue(key); |
| if (obj == null) { |
| return null; |
| } |
| SkylarkType.checkType(obj, type, key); |
| return type.cast(obj); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>Overrides {@link ClassObject#getFieldNames()}, but does not allow {@link EvalException} to |
| * be thrown. |
| */ |
| @Override |
| public abstract ImmutableCollection<String> getFieldNames(); |
| |
| /** |
| * Returns the error message format to use for unknown fields. |
| * |
| * <p>By default, it is the one specified by the provider. |
| */ |
| protected String getErrorMessageFormatForUnknownField() { |
| return provider.getErrorMessageFormatForUnknownField(); |
| } |
| |
| @Override |
| public String getErrorMessageForUnknownField(String name) { |
| String suffix = "Available attributes: " |
| + Joiner.on(", ").join(Ordering.natural().sortedCopy(getFieldNames())); |
| return String.format(getErrorMessageFormatForUnknownField(), name) + "\n" + suffix; |
| } |
| |
| @Override |
| public boolean equals(Object otherObject) { |
| if (!(otherObject instanceof Info)) { |
| return false; |
| } |
| Info other = (Info) otherObject; |
| if (this == other) { |
| return true; |
| } |
| if (!this.provider.equals(other.provider)) { |
| return false; |
| } |
| // Compare objects' fields and their values |
| if (!this.getFieldNames().equals(other.getFieldNames())) { |
| return false; |
| } |
| for (String field : getFieldNames()) { |
| if (!this.getValue(field).equals(other.getValue(field))) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public int hashCode() { |
| List<String> fields = new ArrayList<>(getFieldNames()); |
| Collections.sort(fields); |
| List<Object> objectsToHash = new ArrayList<>(); |
| objectsToHash.add(provider); |
| for (String field : fields) { |
| objectsToHash.add(field); |
| objectsToHash.add(getValue(field)); |
| } |
| return Objects.hashCode(objectsToHash.toArray()); |
| } |
| |
| /** |
| * Convert the object to string using Skylark syntax. The output tries to be reversible (but there |
| * is no guarantee, it depends on the actual values). |
| */ |
| @Override |
| public void repr(SkylarkPrinter printer) { |
| boolean first = true; |
| printer.append("struct("); |
| // Sort by key to ensure deterministic output. |
| for (String fieldName : Ordering.natural().sortedCopy(getFieldNames())) { |
| if (!first) { |
| printer.append(", "); |
| } |
| first = false; |
| printer.append(fieldName); |
| printer.append(" = "); |
| printer.repr(getValue(fieldName)); |
| } |
| printer.append(")"); |
| } |
| |
| @Override |
| public String toString() { |
| return Printer.repr(this); |
| } |
| } |