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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.collect.ImmutableList;
import com.google.devtools.build.lib.util.Preconditions;
import java.io.IOException;
import java.util.List;
/**
* Syntax node for an if/else statement.
*/
public final class IfStatement extends Statement {
/**
* Syntax node for an [el]if statement.
*
* <p>This extends Statement because it implements {@code doExec} and {@code validate}, but it
* is not actually an independent statement in the grammar.
*/
public static final class ConditionalStatements extends Statement {
private final Expression condition;
private final ImmutableList<Statement> statements;
public ConditionalStatements(Expression condition, List<Statement> statements) {
this.condition = Preconditions.checkNotNull(condition);
this.statements = ImmutableList.copyOf(statements);
}
@Override
void doExec(Environment env) throws EvalException, InterruptedException {
for (Statement stmt : statements) {
stmt.exec(env);
}
}
// No prettyPrint function; handled directly by IfStatement#prettyPrint.
@Override
public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
throw new UnsupportedOperationException("Cannot pretty print ConditionalStatements node");
}
@Override
public String toString() {
return "[el]if " + condition + ": " + statements + "\n";
}
@Override
public void accept(SyntaxTreeVisitor visitor) {
visitor.visit(this);
}
public Expression getCondition() {
return condition;
}
public ImmutableList<Statement> getStatements() {
return statements;
}
@Override
void validate(ValidationEnvironment env) throws EvalException {
condition.validate(env);
validateStmts(env, statements);
}
}
/** "if" or "elif" clauses. Must be non-empty. */
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.
*/
public 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 void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
String clauseWord = "if ";
for (ConditionalStatements condStmt : thenBlocks) {
printIndent(buffer, indentLevel);
buffer.append(clauseWord);
condStmt.getCondition().prettyPrint(buffer);
buffer.append(":\n");
printSuite(buffer, condStmt.getStatements(), indentLevel);
clauseWord = "elif ";
}
if (!elseBlock.isEmpty()) {
printIndent(buffer, indentLevel);
buffer.append("else:\n");
printSuite(buffer, elseBlock, indentLevel);
}
}
@Override
public String toString() {
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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