Copyright (c) 2000, 2014 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
    Stephan Herrmann - Contributions for
							bug 349326 - [1.7] new warning for missing try-with-resources
							bug 368546 - [compiler][resource] Avoid remaining false positives found when compiling the Eclipse SDK
							bug 345305 - [compiler][null] Compiler misidentifies a case of "variable can only be null"
							bug 383368 - [compiler][null] syntactic null analysis for field references
							bug 402993 - [null] Follow up of bug 401088: Missing warning about redundant null check
							Bug 440282 - [resource] Resource leak detection false negative with empty finally block
/*******************************************************************************
 * Copyright (c) 2000, 2014 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Stephan Herrmann - Contributions for
 *								bug 349326 - [1.7] new warning for missing try-with-resources
 *								bug 368546 - [compiler][resource] Avoid remaining false positives found when compiling the Eclipse SDK
 *								bug 345305 - [compiler][null] Compiler misidentifies a case of "variable can only be null"
 *								bug 383368 - [compiler][null] syntactic null analysis for field references
 *								bug 402993 - [null] Follow up of bug 401088: Missing warning about redundant null check
 *								Bug 440282 - [resource] Resource leak detection false negative with empty finally block
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;

import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.codegen.*;
import org.eclipse.jdt.internal.compiler.flow.*;
import org.eclipse.jdt.internal.compiler.lookup.*;

public class Block extends Statement {

	public Statement[] statements;
	public int explicitDeclarations;
	// the number of explicit declaration , used to create scope
	public BlockScope scope;

public Block(int explicitDeclarations) {
	this.explicitDeclarations = explicitDeclarations;
}

@Override
public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
	// empty block
	if (this.statements == null)	return flowInfo;
	int complaintLevel = (flowInfo.reachMode() & FlowInfo.UNREACHABLE) != 0 ? Statement.COMPLAINED_FAKE_REACHABLE : Statement.NOT_COMPLAINED;
	boolean enableSyntacticNullAnalysisForFields = currentScope.compilerOptions().enableSyntacticNullAnalysisForFields;
	for (int i = 0, max = this.statements.length; i < max; i++) {
		Statement stat = this.statements[i];
		if ((complaintLevel = stat.complainIfUnreachable(flowInfo, this.scope, complaintLevel, true)) < Statement.COMPLAINED_UNREACHABLE) {
			flowInfo = stat.analyseCode(this.scope, flowContext, flowInfo);
		}
		// record the effect of stat on the finally block of an enclosing try-finally, if any:
		flowContext.mergeFinallyNullInfo(flowInfo);
		if (enableSyntacticNullAnalysisForFields) {
			flowContext.expireNullCheckedFieldInfo();
		}
	}
	if (this.scope != currentScope) {
		// if block is tracking any resources other than the enclosing 'currentScope', analyse them now:
		this.scope.checkUnclosedCloseables(flowInfo, flowContext, null, null);
	}
	if (this.explicitDeclarations > 0) {
		// cleanup assignment info for locals that are scoped to this block:
		LocalVariableBinding[] locals = this.scope.locals;
		if (locals != null) {
			int numLocals = this.scope.localIndex;
			for (int i = 0; i < numLocals; i++) {
				flowInfo.resetAssignmentInfo(locals[i]);
			}
		}
	}
	return flowInfo;
}
Code generation for a block
/**
 * Code generation for a block
 */
@Override
public void generateCode(BlockScope currentScope, CodeStream codeStream) {
	if ((this.bits & IsReachable) == 0) {
		return;
	}
	int pc = codeStream.position;
	if (this.statements != null) {
		for (int i = 0, max = this.statements.length; i < max; i++) {
			this.statements[i].generateCode(this.scope, codeStream);
		}
	} // for local variable debug attributes
	if (this.scope != currentScope) { // was really associated with its own scope
		codeStream.exitUserScope(this.scope);
	}
	codeStream.recordPositionsFrom(pc, this.sourceStart);
}

@Override
public boolean isEmptyBlock() {
	return this.statements == null;
}

public StringBuffer printBody(int indent, StringBuffer output) {
	if (this.statements == null) return output;
	for (int i = 0; i < this.statements.length; i++) {
		this.statements[i].printStatement(indent + 1, output);
		output.append('\n');
	}
	return output;
}

@Override
public StringBuffer printStatement(int indent, StringBuffer output) {
	printIndent(indent, output);
	output.append("{\n"); //$NON-NLS-1$
	printBody(indent, output);
	return printIndent(indent, output).append('}');
}

@Override
public void resolve(BlockScope upperScope) {
	if ((this.bits & UndocumentedEmptyBlock) != 0) {
		upperScope.problemReporter().undocumentedEmptyBlock(this.sourceStart, this.sourceEnd);
	}
	if (this.statements != null) {
		this.scope =
			this.explicitDeclarations == 0
				? upperScope
				: new BlockScope(upperScope, this.explicitDeclarations);
		for (int i = 0, length = this.statements.length; i < length; i++) {
			this.statements[i].resolve(this.scope);
		}
	}
}

public void resolveUsing(BlockScope givenScope) {
	if ((this.bits & UndocumentedEmptyBlock) != 0) {
		givenScope.problemReporter().undocumentedEmptyBlock(this.sourceStart, this.sourceEnd);
	}
	// this optimized resolve(...) is sent only on none empty blocks
	this.scope = givenScope;
	if (this.statements != null) {
		for (int i = 0, length = this.statements.length; i < length; i++) {
			this.statements[i].resolve(this.scope);
		}
	}
}

@Override
public void traverse(ASTVisitor visitor, BlockScope blockScope) {
	if (visitor.visit(this, blockScope)) {
		if (this.statements != null) {
			for (int i = 0, length = this.statements.length; i < length; i++)
				this.statements[i].traverse(visitor, this.scope);
		}
	}
	visitor.endVisit(this, blockScope);
}

Dispatch the call on its last statement.
/**
 * Dispatch the call on its last statement.
 */
@Override
public void branchChainTo(BranchLabel label) {
	if (this.statements != null) {
		this.statements[this.statements.length - 1].branchChainTo(label);
	}
}

// A block does not complete normally if the last statement which we presume is reachable does not complete normally.
@Override
public boolean doesNotCompleteNormally() {
	int length = this.statements == null ? 0 : this.statements.length;
	return length > 0 && this.statements[length - 1].doesNotCompleteNormally();
}

@Override
public boolean completesByContinue() {
	int length = this.statements == null ? 0 : this.statements.length;
	return length > 0 && this.statements[length - 1].completesByContinue();
}
}