1/*
2 * Copyright 2013-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <folly/experimental/exception_tracer/StackTrace.h>
18
19#include <cassert>
20#include <cstdlib>
21#include <new>
22
23#include <folly/experimental/symbolizer/StackTrace.h>
24
25namespace folly {
26namespace exception_tracer {
27
28class StackTraceStack::Node : public StackTrace {
29 public:
30 static Node* allocate();
31 void deallocate();
32
33 Node* next;
34
35 private:
36 Node() : next(nullptr) {}
37 ~Node() {}
38};
39
40auto StackTraceStack::Node::allocate() -> Node* {
41 // Null pointer on error, please.
42 return new (std::nothrow) Node();
43}
44
45void StackTraceStack::Node::deallocate() {
46 delete this;
47}
48
49bool StackTraceStack::pushCurrent() {
50 checkGuard();
51 auto node = Node::allocate();
52 if (!node) {
53 // cannot allocate memory
54 return false;
55 }
56
57 ssize_t n = folly::symbolizer::getStackTrace(node->addresses, kMaxFrames);
58 if (n == -1) {
59 node->deallocate();
60 return false;
61 }
62 node->frameCount = n;
63
64 node->next = top_;
65 top_ = node;
66 return true;
67}
68
69bool StackTraceStack::pop() {
70 checkGuard();
71 if (!top_) {
72 return false;
73 }
74
75 auto node = top_;
76 top_ = node->next;
77 node->deallocate();
78 return true;
79}
80
81bool StackTraceStack::moveTopFrom(StackTraceStack& other) {
82 checkGuard();
83 if (!other.top_) {
84 return false;
85 }
86
87 auto node = other.top_;
88 other.top_ = node->next;
89 node->next = top_;
90 top_ = node;
91 return true;
92}
93
94void StackTraceStack::clear() {
95 checkGuard();
96 while (top_) {
97 pop();
98 }
99}
100
101StackTrace* StackTraceStack::top() {
102 checkGuard();
103 return top_;
104}
105
106StackTrace* StackTraceStack::next(StackTrace* p) {
107 checkGuard();
108 assert(p);
109 return static_cast<Node*>(p)->next;
110}
111} // namespace exception_tracer
112} // namespace folly
113