/*
* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.nashorn.internal.ir;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import jdk.nashorn.internal.ir.annotations.Immutable;
import jdk.nashorn.internal.ir.visitor.NodeVisitor;
/**
* IR representation of a TRY statement.
*/
@Immutable
public final class TryNode extends LexicalContextStatement implements JoinPredecessor {
private static final long serialVersionUID = 1L;
/** Try statements. */
private final Block body;
/** List of catch clauses. */
private final List<Block> catchBlocks;
/** Finally clause. */
private final Block finallyBody;
/**
* List of inlined finally blocks. The structure of every inlined finally is:
* Block(LabelNode(label, Block(finally-statements, (JumpStatement|ReturnNode)?))).
* That is, the block has a single LabelNode statement with the label and a block containing the
* statements of the inlined finally block with the jump or return statement appended (if the finally
* block was not terminal; the original jump/return is simply ignored if the finally block itself
* terminates). The reason for this somewhat strange arrangement is that we didn't want to create a
* separate class for the (label, BlockStatement pair) but rather reused the already available LabelNode.
* However, if we simply used List<LabelNode> without wrapping the label nodes in an additional Block,
* that would've thrown off visitors relying on BlockLexicalContext -- same reason why we never use
* Statement as the type of bodies of e.g. IfNode, WhileNode etc. but rather blockify them even when they're
* single statements.
*/
private final List<Block> inlinedFinallies;
/** Exception symbol. */
private final Symbol exception;
private final LocalVariableConversion conversion;
/**
* Constructor
*
* @param lineNumber lineNumber
* @param token token
* @param finish finish
* @param body try node body
* @param catchBlocks list of catch blocks in order
* @param finallyBody body of finally block or null if none
*/
public TryNode(final int lineNumber, final long token, final int finish, final Block body, final List<Block> catchBlocks, final Block finallyBody) {
super(lineNumber, token, finish);
this.body = body;
this.catchBlocks = catchBlocks;
this.finallyBody = finallyBody;
this.conversion = null;
this.inlinedFinallies = Collections.emptyList();
this.exception = null;
}
private TryNode(final TryNode tryNode, final Block body, final List<Block> catchBlocks, final Block finallyBody, final LocalVariableConversion conversion, final List<Block> inlinedFinallies, final Symbol exception) {
super(tryNode);
this.body = body;
this.catchBlocks = catchBlocks;
this.finallyBody = finallyBody;
this.conversion = conversion;
this.inlinedFinallies = inlinedFinallies;
this.exception = exception;
}
@Override
public Node ensureUniqueLabels(final LexicalContext lc) {
//try nodes are never in lex context
return new TryNode(this, body, catchBlocks, finallyBody, conversion, inlinedFinallies, exception);
}
@Override
public boolean isTerminal() {
if (body.isTerminal()) {
for (final Block catchBlock : getCatchBlocks()) {
if (!catchBlock.isTerminal()) {
return false;
}
}
return true;
}
return false;
}
/**
* Assist in IR navigation.
* @param visitor IR navigating visitor.
*/
@Override
public Node accept(final LexicalContext lc, final NodeVisitor<? extends LexicalContext> visitor) {
if (visitor.enterTryNode(this)) {
// Need to do finallybody first for termination analysis. TODO still necessary?
final Block newFinallyBody = finallyBody == null ? null : (Block)finallyBody.accept(visitor);
final Block newBody = (Block)body.accept(visitor);
return visitor.leaveTryNode(
setBody(lc, newBody).
setFinallyBody(lc, newFinallyBody).
setCatchBlocks(lc, Node.accept(visitor, catchBlocks)).
setInlinedFinallies(lc, Node.accept(visitor, inlinedFinallies)));
}
return this;
}
@Override
public void toString(final StringBuilder sb, final boolean printType) {
sb.append("try ");
}
/**
* Get the body for this try block
* @return body
*/
public Block getBody() {
return body;
}
/**
* Reset the body of this try block
* @param lc current lexical context
* @param body new body
* @return new TryNode or same if unchanged
*/
public TryNode setBody(final LexicalContext lc, final Block body) {
if (this.body == body) {
return this;
}
return Node.replaceInLexicalContext(lc, this, new TryNode(this, body, catchBlocks, finallyBody, conversion, inlinedFinallies, exception));
}
/**
* Get the catches for this try block
* @return a list of catch nodes
*/
public List<CatchNode> getCatches() {
final List<CatchNode> catches = new ArrayList<>(catchBlocks.size());
for (final Block catchBlock : catchBlocks) {
catches.add(getCatchNodeFromBlock(catchBlock));
}
return Collections.unmodifiableList(catches);
}
private static CatchNode getCatchNodeFromBlock(final Block catchBlock) {
return (CatchNode)catchBlock.getStatements().get(0);
}
/**
* Get the catch blocks for this try block
* @return a list of blocks
*/
public List<Block> getCatchBlocks() {
return Collections.unmodifiableList(catchBlocks);
}
/**
* Set the catch blocks of this try
* @param lc current lexical context
* @param catchBlocks list of catch blocks
* @return new TryNode or same if unchanged
*/
public TryNode setCatchBlocks(final LexicalContext lc, final List<Block> catchBlocks) {
if (this.catchBlocks == catchBlocks) {
return this;
}
return Node.replaceInLexicalContext(lc, this, new TryNode(this, body, catchBlocks, finallyBody, conversion, inlinedFinallies, exception));
}
/**
* Get the exception symbol for this try block
* @return a symbol for the compiler to store the exception in
*/
public Symbol getException() {
return exception;
}
/**
* Set the exception symbol for this try block
* @param lc lexical context
* @param exception a symbol for the compiler to store the exception in
* @return new TryNode or same if unchanged
*/
public TryNode setException(final LexicalContext lc, final Symbol exception) {
if (this.exception == exception) {
return this;
}
return Node.replaceInLexicalContext(lc, this, new TryNode(this, body, catchBlocks, finallyBody, conversion, inlinedFinallies, exception));
}
/**
* Get the body of the finally clause for this try
* @return finally body, or null if no finally
*/
public Block getFinallyBody() {
return finallyBody;
}
/**
* Get the inlined finally block with the given label name. This returns the actual finally block in the
* {@link LabelNode}, not the outer wrapper block for the {@link LabelNode}.
* @param labelName the name of the inlined finally's label
* @return the requested finally block, or null if no finally block's label matches the name.
*/
public Block getInlinedFinally(final String labelName) {
for(final Block inlinedFinally: inlinedFinallies) {
final LabelNode labelNode = getInlinedFinallyLabelNode(inlinedFinally);
if (labelNode.getLabelName().equals(labelName)) {
return labelNode.getBody();
}
}
return null;
}
private static LabelNode getInlinedFinallyLabelNode(final Block inlinedFinally) {
return (LabelNode)inlinedFinally.getStatements().get(0);
}
/**
* Given an outer wrapper block for the {@link LabelNode} as returned by {@link #getInlinedFinallies()},
* returns its actual inlined finally block.
* @param inlinedFinally the outer block for inlined finally, as returned as an element of
* {@link #getInlinedFinallies()}.
* @return the block contained in the {@link LabelNode} contained in the passed block.
*/
public static Block getLabelledInlinedFinallyBlock(final Block inlinedFinally) {
return getInlinedFinallyLabelNode(inlinedFinally).getBody();
}
/**
* Returns a list of inlined finally blocks. Note that this returns a list of {@link Block}s such that each one of
* them has a single {@link LabelNode}, which in turn contains the label name for the finally block and the
* actual finally block. To safely extract the actual finally block, use
* {@link #getLabelledInlinedFinallyBlock(Block)}.
* @return a list of inlined finally blocks.
*/
public List<Block> getInlinedFinallies() {
return Collections.unmodifiableList(inlinedFinallies);
}
/**
* Set the finally body of this try
* @param lc current lexical context
* @param finallyBody new finally body
* @return new TryNode or same if unchanged
*/
public TryNode setFinallyBody(final LexicalContext lc, final Block finallyBody) {
if (this.finallyBody == finallyBody) {
return this;
}
return Node.replaceInLexicalContext(lc, this, new TryNode(this, body, catchBlocks, finallyBody, conversion, inlinedFinallies, exception));
}
/**
* Set the inlined finally blocks of this try. Each element should be a block with a single statement that is a
* {@link LabelNode} with a unique label, and the block within the label node should contain the actual inlined
* finally block.
* @param lc current lexical context
* @param inlinedFinallies list of inlined finally blocks
* @return new TryNode or same if unchanged
*/
public TryNode setInlinedFinallies(final LexicalContext lc, final List<Block> inlinedFinallies) {
if (this.inlinedFinallies == inlinedFinallies) {
return this;
}
assert checkInlinedFinallies(inlinedFinallies);
return Node.replaceInLexicalContext(lc, this, new TryNode(this, body, catchBlocks, finallyBody, conversion, inlinedFinallies, exception));
}
private static boolean checkInlinedFinallies(final List<Block> inlinedFinallies) {
if (!inlinedFinallies.isEmpty()) {
final Set<String> labels = new HashSet<>();
for (final Block inlinedFinally : inlinedFinallies) {
final List<Statement> stmts = inlinedFinally.getStatements();
assert stmts.size() == 1;
final LabelNode ln = getInlinedFinallyLabelNode(inlinedFinally);
assert labels.add(ln.getLabelName()); // unique label
}
}
return true;
}
@Override
public JoinPredecessor setLocalVariableConversion(final LexicalContext lc, final LocalVariableConversion conversion) {
if(this.conversion == conversion) {
return this;
}
return new TryNode(this, body, catchBlocks, finallyBody, conversion, inlinedFinallies, exception);
}
@Override
public LocalVariableConversion getLocalVariableConversion() {
return conversion;
}
}