1 /*
2  * Copyright 2016-2018 Max Kellermann <max.kellermann@gmail.com>
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * - Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  *
11  * - Redistributions in binary form must reproduce the above copyright
12  * notice, this list of conditions and the following disclaimer in the
13  * documentation and/or other materials provided with the
14  * distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
19  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
20  * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
25  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
27  * OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include "Exception.hxx"
31 
32 #include <utility>
33 
34 template<typename T>
35 static void
AppendNestedMessage(std::string & result,T && e,const char * fallback,const char * separator)36 AppendNestedMessage(std::string &result, T &&e,
37 		    const char *fallback, const char *separator) noexcept
38 {
39 	try {
40 		std::rethrow_if_nested(std::forward<T>(e));
41 	} catch (const std::exception &nested) {
42 		result += separator;
43 		result += nested.what();
44 		AppendNestedMessage(result, nested, fallback, separator);
45 	} catch (const std::nested_exception &ne) {
46 		AppendNestedMessage(result, ne, fallback, separator);
47 	} catch (const char *s) {
48 		result += separator;
49 		result += s;
50 	} catch (...) {
51 		result += separator;
52 		result += fallback;
53 	}
54 }
55 
56 std::string
GetFullMessage(const std::exception & e,const char * fallback,const char * separator)57 GetFullMessage(const std::exception &e,
58 	       const char *fallback, const char *separator) noexcept
59 {
60 	std::string result = e.what();
61 	AppendNestedMessage(result, e, fallback, separator);
62 	return result;
63 }
64 
65 std::string
GetFullMessage(std::exception_ptr ep,const char * fallback,const char * separator)66 GetFullMessage(std::exception_ptr ep,
67 	       const char *fallback, const char *separator) noexcept
68 {
69 	try {
70 		std::rethrow_exception(std::move(ep));
71 	} catch (const std::exception &e) {
72 		return GetFullMessage(e, fallback, separator);
73 	} catch (const std::nested_exception &ne) {
74 		return GetFullMessage(ne.nested_ptr(), fallback, separator);
75 	} catch (const char *s) {
76 		return s;
77 	} catch (...) {
78 		return fallback;
79 	}
80 }
81