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// 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 com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import java.util.List;
// TODO(bazel-team): maybe we should get rid of the ConditionalStatements and
// create a chain of if-else statements for elif-s.
/**
* Syntax node for an if/else statement.
*/
public final class IfStatement extends Statement {
/**
* Syntax node for an [el]if statement.
*/
static final class ConditionalStatements extends Statement {
private final Expression condition;
private final ImmutableList<Statement> stmts;
public ConditionalStatements(Expression condition, List<Statement> stmts) {
this.condition = Preconditions.checkNotNull(condition);
this.stmts = ImmutableList.copyOf(stmts);
}
@Override
void doExec(Environment env) throws EvalException, InterruptedException {
for (Statement stmt : stmts) {
stmt.exec(env);
}
}
@Override
public String toString() {
// TODO(bazel-team): see TODO in the outer class
return "[el]if " + condition + ": " + stmts + "\n";
}
@Override
public void accept(SyntaxTreeVisitor visitor) {
visitor.visit(this);
}
Expression getCondition() {
return condition;
}
ImmutableList<Statement> getStmts() {
return stmts;
}
@Override
void validate(ValidationEnvironment env) throws EvalException {
// EvalUtils.toBoolean() evaluates everything so we don't need type check here.
condition.validate(env);
validateStmts(env, stmts);
}
}
private final ImmutableList<ConditionalStatements> thenBlocks;
private final ImmutableList<Statement> elseBlock;
/**
* Constructs a if-elif-else statement. The else part is mandatory, but the list may be empty.
* ThenBlocks has to have at least one element.
*/
IfStatement(List<ConditionalStatements> thenBlocks, List<Statement> elseBlock) {
Preconditions.checkArgument(!thenBlocks.isEmpty());
this.thenBlocks = ImmutableList.copyOf(thenBlocks);
this.elseBlock = ImmutableList.copyOf(elseBlock);
}
public ImmutableList<ConditionalStatements> getThenBlocks() {
return thenBlocks;
}
public ImmutableList<Statement> getElseBlock() {
return elseBlock;
}
@Override
public String toString() {
// TODO(bazel-team): if we want to print the complete statement, the function
// needs an extra argument to specify indentation level.
// As guaranteed by the constructor, there must be at least one element in thenBlocks.
return String.format("if %s:\n", thenBlocks.get(0).getCondition());
}
@Override
void doExec(Environment env) throws EvalException, InterruptedException {
for (ConditionalStatements stmt : thenBlocks) {
if (EvalUtils.toBoolean(stmt.getCondition().eval(env))) {
stmt.exec(env);
return;
}
}
for (Statement stmt : elseBlock) {
stmt.exec(env);
}
}
@Override
public void accept(SyntaxTreeVisitor visitor) {
visitor.visit(this);
}
@Override
void validate(ValidationEnvironment env) throws EvalException {
env.startTemporarilyDisableReadonlyCheckSession();
for (ConditionalStatements stmts : thenBlocks) {
stmts.validate(env);
}
validateStmts(env, elseBlock);
env.finishTemporarilyDisableReadonlyCheckSession();
}
private static void validateStmts(ValidationEnvironment env, List<Statement> stmts)
throws EvalException {
for (Statement stmt : stmts) {
stmt.validate(env);
}
env.finishTemporarilyDisableReadonlyCheckBranch();
}
}
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