GCC Code Coverage Report

Directory: cvmfs/
File: cvmfs/shortstring.h
Date: 2026-04-26 02:35:59
Exec Total Coverage
Lines: 91 108 84.3%
Branches: 34 50 68.0%
Line Branch Exec Source
1 /**
2 * This file is part of the CernVM File System.
3 *
4 * Implements a string class that stores short strings on the stack and
5 * malloc's a std::string on the heap on overflow. Used for file names and
6 * path names that are usually small.
7 */
8
9 #ifndef CVMFS_SHORTSTRING_H_
10 #define CVMFS_SHORTSTRING_H_
11
12 #include <algorithm>
13 #include <cstring>
14 #include <string>
15
16 #include "util/atomic.h"
17
18 #ifdef CVMFS_NAMESPACE_GUARD
19 namespace CVMFS_NAMESPACE_GUARD {
20 #endif
21
22 const unsigned char kDefaultMaxName = 25;
23 const unsigned char kDefaultMaxLink = 25;
24 const unsigned char kDefaultMaxPath = 200;
25
26 template<unsigned char StackSize, char Type>
27 class ShortString {
28 public:
29 179981202 ShortString() : long_string_(NULL), length_(0) {
30 #ifdef DEBUGMSG
31 179981202 atomic_inc64(&num_instances_);
32 #endif
33 179981202 }
34 75034178 ShortString(const ShortString &other) : long_string_(NULL) {
35 #ifdef DEBUGMSG
36 150068356 atomic_inc64(&num_instances_);
37 #endif
38 150115546 Assign(other);
39 150043708 }
40 132337 ShortString(const char *chars, const unsigned length) : long_string_(NULL) {
41 #ifdef DEBUGMSG
42 132337 atomic_inc64(&num_instances_);
43 #endif
44 132529 Assign(chars, length);
45 132413 }
46 60464504 explicit ShortString(const std::string &std_string) : long_string_(NULL) {
47 #ifdef DEBUGMSG
48 60464504 atomic_inc64(&num_instances_);
49 #endif
50 60623264 Assign(std_string.data(), std_string.length());
51 60567384 }
52
53 31870314 ShortString &operator=(const ShortString &other) {
54
1/2
✓ Branch 0 taken 15936981 times.
✗ Branch 1 not taken.
 31870314 if (this != &other)
55 31873962 Assign(other);
56 31815090 return *this;
57 }
58
59
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 181124706 times.
 362249412 ~ShortString() { delete long_string_; }
60
61 242757306 void Assign(const char *chars, const unsigned length) {
62
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 121378653 times.
 242757306 delete long_string_;
63 242714868 long_string_ = NULL;
64 242714868 this->length_ = length;
65
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 121357434 times.
 242714868 if (length > StackSize) {
66 #ifdef DEBUGMSG
67 ✗ atomic_inc64(&num_overflows_);
68 #endif
69 ✗ long_string_ = new std::string(chars, length);
70 } else {
71
2/2
✓ Branch 0 taken 121096380 times.
✓ Branch 1 taken 261054 times.
 242714868 if (length)
72 242192760 memcpy(stack_, chars, length);
73 }
74 242714868 }
75
76 181939902 void Assign(const ShortString &other) {
77 181939902 Assign(other.GetChars(), other.GetLength());
78 181863840 }
79
80 103569 void Append(const char *chars, const unsigned length) {
81
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 103569 times.
 103569 if (long_string_) {
82 ✗ long_string_->append(chars, length);
83 ✗ return;
84 }
85
86 103569 const unsigned new_length = this->length_ + length;
87
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 103569 times.
 103569 if (new_length > StackSize) {
88 #ifdef DEBUGMSG
89 ✗ atomic_inc64(&num_overflows_);
90 #endif
91 ✗ long_string_ = new std::string();
92 ✗ long_string_->reserve(new_length);
93 ✗ long_string_->assign(stack_, length_);
94 ✗ long_string_->append(chars, length);
95 ✗ return;
96 }
97
2/2
✓ Branch 0 taken 101617 times.
✓ Branch 1 taken 1952 times.
 103569 if (length > 0)
98 101617 memcpy(&stack_[this->length_], chars, length);
99 103569 this->length_ = new_length;
100 }
101
102 /**
103 * Truncates the current string to be of size smaller or equal to current size
104 *
105 * Note: Can lead to a heap allocated string that is shorter than
106 * the reserved stack space.
107 */
108 2646 void Truncate(unsigned new_length) {
109
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 2646 times.
 2646 assert(new_length <= this->GetLength());
110
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 2646 times.
 2646 if (long_string_) {
111 ✗ long_string_->erase(new_length);
112 ✗ return;
113 }
114 2646 this->length_ = new_length;
115 }
116
117 void Clear() {
118 delete long_string_;
119 long_string_ = NULL;
120 length_ = 0;
121 }
122
123 243230974 const char *GetChars() const {
124
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 121615487 times.
 243230974 if (long_string_) {
125 ✗ return long_string_->data();
126 } else {
127 243230974 return stack_;
128 }
129 }
130
131 243832608 unsigned GetLength() const {
132
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 121916304 times.
 243832608 if (long_string_)
133 ✗ return long_string_->length();
134 243832608 return length_;
135 }
136
137 42146 bool IsEmpty() const { return GetLength() == 0; }
138
139 30292855 std::string ToString() const {
140
1/2
✓ Branch 4 taken 30291173 times.
✗ Branch 5 not taken.
 30292855 return std::string(this->GetChars(), this->GetLength());
141 }
142
143 122104 const char *c_str() const {
144
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 77062 times.
 122104 if (long_string_)
145 ✗ return long_string_->c_str();
146
147 122104 char *c = const_cast<char *>(stack_) + length_;
148 122104 *c = '\0';
149 122104 return stack_;
150 }
151
152 30881 bool operator==(const ShortString &other) const {
153 30881 const unsigned this_length = this->GetLength();
154 30881 const unsigned other_length = other.GetLength();
155
2/2
✓ Branch 0 taken 16731 times.
✓ Branch 1 taken 11258 times.
 30881 if (this_length != other_length)
156 17068 return false;
157
2/2
✓ Branch 0 taken 6703 times.
✓ Branch 1 taken 4555 times.
 13813 if (this_length == 0)
158 8538 return true;
159
160 5275 return memcmp(this->GetChars(), other.GetChars(), this_length) == 0;
161 }
162
163 18720 bool operator!=(const ShortString &other) const { return !(*this == other); }
164
165 24989 bool operator<(const ShortString &other) const {
166 24989 const unsigned this_length = this->GetLength();
167 24989 const unsigned other_length = other.GetLength();
168
169
2/2
✓ Branch 0 taken 6650 times.
✓ Branch 1 taken 18339 times.
 24989 if (this_length < other_length)
170 6650 return true;
171
2/2
✓ Branch 0 taken 3134 times.
✓ Branch 1 taken 15205 times.
 18339 if (this_length > other_length)
172 3134 return false;
173
174 15205 const char *this_chars = this->GetChars();
175 15205 const char *other_chars = other.GetChars();
176
2/2
✓ Branch 0 taken 112173 times.
✓ Branch 1 taken 14008 times.
 126181 for (unsigned i = 0; i < this_length; ++i) {
177
2/2
✓ Branch 0 taken 900 times.
✓ Branch 1 taken 111273 times.
 112173 if (this_chars[i] < other_chars[i])
178 900 return true;
179
2/2
✓ Branch 0 taken 297 times.
✓ Branch 1 taken 110976 times.
 111273 if (this_chars[i] > other_chars[i])
180 297 return false;
181 }
182 14008 return false;
183 }
184
185 26628 bool StartsWith(const ShortString &other) const {
186 26628 const unsigned this_length = this->GetLength();
187 26628 const unsigned other_length = other.GetLength();
188
2/2
✓ Branch 0 taken 1080 times.
✓ Branch 1 taken 25548 times.
 26628 if (this_length < other_length)
189 1080 return false;
190
191 25548 return memcmp(this->GetChars(), other.GetChars(), other_length) == 0;
192 }
193
194 10299 ShortString Suffix(const unsigned start_at) const {
195 10299 const unsigned length = this->GetLength();
196
2/2
✓ Branch 0 taken 188 times.
✓ Branch 1 taken 10111 times.
 10299 if (start_at >= length)
197 188 return ShortString("", 0);
198
199 10111 return ShortString(this->GetChars() + start_at, length - start_at);
200 }
201
202 ✗ static uint64_t num_instances() { return atomic_read64(&num_instances_); }
203 ✗ static uint64_t num_overflows() { return atomic_read64(&num_overflows_); }
204
205 private:
206 std::string *long_string_;
207 char stack_[StackSize + 1]; // +1 to add a final '\0' if necessary
208 unsigned char length_;
209 static atomic_int64 num_overflows_;
210 static atomic_int64 num_instances_;
211 }; // class ShortString
212
213 typedef ShortString<kDefaultMaxPath, 0> PathString;
214 typedef ShortString<kDefaultMaxName, 1> NameString;
215 typedef ShortString<kDefaultMaxLink, 2> LinkString;
216
217 template<unsigned char StackSize, char Type>
218 atomic_int64 ShortString<StackSize, Type>::num_overflows_ = 0;
219 template<unsigned char StackSize, char Type>
220 atomic_int64 ShortString<StackSize, Type>::num_instances_ = 0;
221
222 // See posix.cc for the std::string counterparts
223 PathString GetParentPath(const PathString &path);
224 NameString GetFileName(const PathString &path);
225
226 bool IsSubPath(const PathString &parent, const PathString &path);
227
228
229 #ifdef CVMFS_NAMESPACE_GUARD
230 } // namespace CVMFS_NAMESPACE_GUARD
231 #endif
232
233 #endif // CVMFS_SHORTSTRING_H_
234