1 /*
   2  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 package jdk.internal.jshell.debug;
  25 
  26 import java.io.PrintStream;
  27 import java.util.HashMap;
  28 import java.util.Map;
  29 import jdk.jshell.JShell;
  30 
  31 /**
  32 /**
  33  * This class is used to externally control output messages for debugging the
  34  * implementation of the JShell API.
  35  * <p>
  36  * This is not part of the SPI, not API.
  37  */
  38 public class InternalDebugControl {
  39 
  40     /**
  41      * This is a static only class; The constructor should never be called.
  42      */
  43     private InternalDebugControl() {
  44     }
  45 
  46     /**
  47      * General debugging.
  48      */
  49     public static final int DBG_GEN = 0b0000001;
  50 
  51     /**
  52      * File manager debuging.
  53      */
  54     public static final int DBG_FMGR = 0b0000010;
  55 
  56     /**
  57      * Completion analysis debugging.
  58      */
  59     public static final int DBG_COMPA = 0b0000100;
  60 
  61     /**
  62      * Dependency debugging.
  63      */
  64     public static final int DBG_DEP = 0b0001000;
  65 
  66     /**
  67      * Execution control channel debugging.
  68      */
  69     public static final int DBG_EC  = 0b0010000;
  70 
  71     /**
  72      * Event debugging.
  73      */
  74     public static final int DBG_EVNT = 0b0010000;
  75 
  76     private static Map<JShell, Integer> debugMap = null;
  77 
  78     /**
  79      * Sets which debug flags are enabled for a given JShell instance. The flags
  80      * are or'ed bits as defined in {@code DBG_*}.
  81      *
  82      * @param state the JShell instance
  83      * @param flags the or'ed debug bits
  84      */
  85     public static void setDebugFlags(JShell state, int flags) {
  86         if (debugMap == null) {
  87             debugMap = new HashMap<>();
  88         }
  89         debugMap.put(state, flags);
  90     }
  91 
  92     /**
  93      * Tests if any of the specified debug flags are enabled.
  94      *
  95      * @param state the JShell instance
  96      * @param flag the {@code DBG_*} bits to check
  97      * @return true if any of the flags are enabled
  98      */
  99     public static boolean isDebugEnabled(JShell state, int flag) {
 100         if (debugMap == null) {
 101             return false;
 102         }
 103         Integer flags = debugMap.get(state);
 104         if (flags == null) {
 105             return false;
 106         }
 107         return (flags & flag) != 0;
 108     }
 109 
 110     /**
 111      * Displays debug info if the specified debug flags are enabled.
 112      *
 113      * @param state the current JShell instance
 114      * @param err the {@code PrintStream} to report on
 115      * @param flags {@code DBG_*} flag bits to check
 116      * @param format format string for the output
 117      * @param args args for the format string
 118      */
 119     public static void debug(JShell state, PrintStream err, int flags, String format, Object... args) {
 120         if (isDebugEnabled(state, flags)) {
 121             err.printf(format, args);
 122         }
 123     }
 124 
 125     /**
 126      * Displays a fatal exception as debug info.
 127      *
 128      * @param state the current JShell instance
 129      * @param err the {@code PrintStream} to report on
 130      * @param ex the fatal Exception
 131      * @param where additional context
 132      */
 133     public static void debug(JShell state, PrintStream err, Throwable ex, String where) {
 134         if (isDebugEnabled(state, 0xFFFFFFFF)) {
 135             err.printf("Fatal error: %s: %s\n", where, ex.getMessage());
 136             ex.printStackTrace(err);
 137         }
 138     }
 139 }