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/*
 * Copyright 2011 The Closure Compiler Authors.
 *
 * 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.javascript.jscomp;

import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
import com.google.javascript.rhino.Node;

/**
 * {@link CheckDebuggerStatement} checks for the presence of the "debugger" statement in JavaScript
 * code. It is appropriate to use this statement while developing JavaScript; however, it is
 * generally undesirable to include it in production code.
 */
class CheckDebuggerStatement extends AbstractPostOrderCallback implements CompilerPass {

  static final DiagnosticType DEBUGGER_STATEMENT_PRESENT =
      DiagnosticType.disabled(
          "JSC_DEBUGGER_STATEMENT_PRESENT",
          "Using the debugger statement can halt your application if the user has a JavaScript"
              + " debugger running.\n"
              + "To disable this check when you want to do debugging, you can suppress this message"
              + " like this:\n"
              // NOTE: Single quotes around curly braces are necessary to prevent them being
              // interpreted as a placeholder for replacement. See MessageFormat javadoc.
              + "  /** @suppress '{'checkDebuggerStatement'}' */\n"
              + "  debugger;");

  private final AbstractCompiler compiler;

  public CheckDebuggerStatement(AbstractCompiler compiler) {
    this.compiler = compiler;
  }

  @Override
  public void process(Node externs, Node root) {
    NodeTraversal.traverse(compiler, root, this);
  }

  @Override
  public void visit(NodeTraversal t, Node n, Node parent) {
    if (n.isDebugger()) {
      t.report(n, DEBUGGER_STATEMENT_PRESENT);
    }
  }
}