| // Copyright 2014 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.syntax; |
| |
| import static com.google.devtools.build.lib.syntax.compiler.ByteCodeUtils.append; |
| |
| import com.google.common.collect.ImmutableList; |
| import com.google.devtools.build.lib.events.Location; |
| import com.google.devtools.build.lib.syntax.SkylarkList.MutableList; |
| import com.google.devtools.build.lib.syntax.SkylarkList.Tuple; |
| import com.google.devtools.build.lib.syntax.compiler.ByteCodeMethodCalls; |
| import com.google.devtools.build.lib.syntax.compiler.ByteCodeUtils; |
| import com.google.devtools.build.lib.syntax.compiler.DebugInfo; |
| import com.google.devtools.build.lib.syntax.compiler.DebugInfo.AstAccessors; |
| import com.google.devtools.build.lib.syntax.compiler.NewObject; |
| import com.google.devtools.build.lib.syntax.compiler.VariableScope; |
| import com.google.devtools.build.lib.util.Preconditions; |
| |
| import net.bytebuddy.implementation.bytecode.ByteCodeAppender; |
| import net.bytebuddy.implementation.bytecode.Duplication; |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.List; |
| |
| /** |
| * Syntax node for list and tuple literals. |
| * |
| * <p>(Note that during evaluation, both list and tuple values are represented by |
| * java.util.List objects, the only difference between them being whether or not |
| * they are mutable.) |
| */ |
| public final class ListLiteral extends Expression { |
| |
| /** |
| * Types of the ListLiteral. |
| */ |
| public static enum Kind {LIST, TUPLE} |
| |
| private final Kind kind; |
| |
| private final List<Expression> exprs; |
| |
| private ListLiteral(Kind kind, List<Expression> exprs) { |
| this.kind = kind; |
| this.exprs = exprs; |
| } |
| |
| public static ListLiteral makeList(List<Expression> exprs) { |
| return new ListLiteral(Kind.LIST, exprs); |
| } |
| |
| public static ListLiteral makeTuple(List<Expression> exprs) { |
| return new ListLiteral(Kind.TUPLE, exprs); |
| } |
| |
| /** A new literal for an empty list, onto which a new location can be specified */ |
| public static ListLiteral emptyList() { |
| return makeList(Collections.<Expression>emptyList()); |
| } |
| |
| /** |
| * Returns the list of expressions for each element of the tuple. |
| */ |
| public List<Expression> getElements() { |
| return exprs; |
| } |
| |
| /** |
| * Returns true if this list is a tuple (a hash table, immutable list). |
| */ |
| public boolean isTuple() { |
| return kind == Kind.TUPLE; |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder sb = new StringBuilder(); |
| Printer.printList(sb, exprs, isTuple(), '"', Printer.SUGGESTED_CRITICAL_LIST_ELEMENTS_COUNT, |
| Printer.SUGGESTED_CRITICAL_LIST_ELEMENTS_STRING_LENGTH); |
| return sb.toString(); |
| } |
| |
| @Override |
| Object doEval(Environment env) throws EvalException, InterruptedException { |
| List<Object> result = new ArrayList<>(); |
| for (Expression expr : exprs) { |
| // Convert NPEs to EvalExceptions. |
| if (expr == null) { |
| throw new EvalException(getLocation(), "null expression in " + this); |
| } |
| result.add(expr.eval(env)); |
| } |
| return isTuple() ? Tuple.copyOf(result) : new MutableList(result, env); |
| } |
| |
| @Override |
| public void accept(SyntaxTreeVisitor visitor) { |
| visitor.visit(this); |
| } |
| |
| @Override |
| void validate(ValidationEnvironment env) throws EvalException { |
| for (Expression expr : exprs) { |
| expr.validate(env); |
| } |
| } |
| |
| @Override |
| ByteCodeAppender compile(VariableScope scope, DebugInfo debugInfo) throws EvalException { |
| AstAccessors debugAccessors = debugInfo.add(this); |
| List<ByteCodeAppender> listConstruction = new ArrayList<>(); |
| if (isTuple()) { |
| append(listConstruction, ByteCodeMethodCalls.BCImmutableList.builder); |
| } else { |
| append( |
| listConstruction, |
| // create a new MutableList object |
| NewObject.fromConstructor(MutableList.class, Mutability.class) |
| .arguments( |
| scope.loadEnvironment(), ByteCodeUtils.invoke(Environment.class, "mutability"))); |
| } |
| |
| for (Expression expression : exprs) { |
| Preconditions.checkNotNull( |
| expression, "List literal at %s contains null expression", getLocation()); |
| ByteCodeAppender compiledValue = expression.compile(scope, debugInfo); |
| if (isTuple()) { |
| listConstruction.add(compiledValue); |
| append( |
| listConstruction, |
| // this re-adds the builder to the stack and we reuse it in the next iteration/after |
| ByteCodeMethodCalls.BCImmutableList.Builder.add); |
| } else { |
| // duplicate the list reference on the stack for reuse in the next iteration/after |
| append(listConstruction, Duplication.SINGLE); |
| listConstruction.add(compiledValue); |
| append( |
| listConstruction, |
| debugAccessors.loadLocation, |
| scope.loadEnvironment(), |
| ByteCodeUtils.cleanInvoke( |
| MutableList.class, "add", Object.class, Location.class, Environment.class)); |
| } |
| } |
| if (isTuple()) { |
| append( |
| listConstruction, |
| ByteCodeMethodCalls.BCImmutableList.Builder.build, |
| ByteCodeUtils.invoke(Tuple.class, "create", ImmutableList.class)); |
| } |
| return ByteCodeUtils.compoundAppender(listConstruction); |
| } |
| } |