1 /*
 2  * Copyright (c) 1999, 2019, 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
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23  */
24 
25 #ifndef SHARE_PRIMS_JVMTIUTIL_HPP
26 #define SHARE_PRIMS_JVMTIUTIL_HPP
27 
28 #include "jvmtifiles/jvmti.h"
29 #include "memory/resourceArea.hpp"
30 #include "prims/jvmtiEventController.hpp"
31 
32 ///////////////////////////////////////////////////////////////
33 //
34 // class JvmtiUtil
35 //
36 // class for miscellaneous jvmti utility static methods
37 //
38 
39 class JvmtiUtil : AllStatic {
40 
41   static ResourceArea* _single_threaded_resource_area;
42 
43   static const char* _error_names[];
44   static const bool  _event_threaded[];
45 
46 public:
47 
48   static ResourceArea* single_threaded_resource_area();
49 
50   static const char* error_name(int num)    { return _error_names[num]; }    // To Do: add range checking
51 
52   static const bool has_event_capability(jvmtiEvent event_type, const jvmtiCapabilities* capabilities_ptr);
53 
54   static const bool  event_threaded(int num) {
55     if (num >= JVMTI_MIN_EVENT_TYPE_VAL && num <= JVMTI_MAX_EVENT_TYPE_VAL) {
56       return _event_threaded[num];
57     }
58     if (num >= EXT_MIN_EVENT_TYPE_VAL && num <= EXT_MAX_EVENT_TYPE_VAL) {
59       return false;
60     }
61     ShouldNotReachHere();
62     return false;
63   }
64 };
65 
66 
67 ///////////////////////////////////////////////////////////////
68 //
69 // class SafeResourceMark
70 //
71 // ResourceMarks that work before threads exist
72 //
73 
74 class SafeResourceMark : public ResourceMark {
75 
76   ResourceArea* safe_resource_area() {
77     Thread* thread;
78 
79     if (Threads::number_of_threads() == 0) {
80       return JvmtiUtil::single_threaded_resource_area();
81     }
82     thread = Thread::current_or_null();
83     if (thread == NULL) {
84       return JvmtiUtil::single_threaded_resource_area();
85     }
86     return thread->resource_area();
87   }
88 
89  public:
90 
91   SafeResourceMark() : ResourceMark(safe_resource_area()) {}
92 
93 };
94 
95 #endif // SHARE_PRIMS_JVMTIUTIL_HPP