GCC Code Coverage Report

Directory: cvmfs/
File: cvmfs/bigqueue.h
Date: 2025-07-27 02:42:09
Exec Total Coverage
Lines: 76 77 98.7%
Branches: 23 32 71.9%
Line Branch Exec Source
1 /**
2 * This file is part of the CernVM File System.
3 *
4 * Similar to bigvector, but queue semantics. Used by the negative entry
5 * tracker. Allocates with mmap in order to avoid memory fragmentation.
6 */
7
8 #ifndef CVMFS_BIGQUEUE_H_
9 #define CVMFS_BIGQUEUE_H_
10
11 #include <algorithm>
12 #include <cassert>
13 #include <cstdlib>
14 #include <new>
15
16 #include "util/smalloc.h"
17
18 template<class Item>
19 class BigQueue {
20 public:
21 220 BigQueue() {
22 220 Alloc(kNumInit);
23 220 size_ = 0;
24 220 }
25
26 explicit BigQueue(const size_t num_items) {
27 const size_t min_items = kNumInit;
28 Alloc(std::max(num_items, min_items));
29 size_ = 0;
30 }
31
32 1 BigQueue(const BigQueue<Item> &other) { CopyFrom(other); }
33
34 43 BigQueue<Item> &operator=(const BigQueue<Item> &other) {
35
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 43 if (&other == this)
36 ✗ return *this;
37
38 43 Dealloc();
39 43 CopyFrom(other);
40 43 return *this;
41 }
42
43 181 ~BigQueue() { Dealloc(); }
44
45 20004212 void PushBack(const Item &item) {
46
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 20004212 if (GetAvailableSpace() == 0) {
47 58 Migrate(1.9 * static_cast<float>(capacity_));
48
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 58 assert(GetAvailableSpace() > 0);
49 }
50
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 20004212 new (head_ + size_) Item(item);
51 20004212 size_++;
52 20004212 }
53
54 20001624 void PopFront() {
55
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 20001624 assert(!IsEmpty());
56 20001624 head_++;
57 20001624 size_--;
58
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 20001624 if ((size_ > kCompactThreshold) && (size_ < (capacity_ / 2)))
59 51 Migrate(static_cast<int>(static_cast<float>(capacity_ * 0.6)));
60 20001624 }
61
62 20004335 bool Peek(Item **item) {
63
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 20004335 if (IsEmpty())
64 373 return false;
65 20003962 *item = head_;
66 20003962 return true;
67 }
68
69 40005959 bool IsEmpty() const { return size_ == 0; }
70
71 43 void Clear() {
72 43 Dealloc();
73 43 Alloc(kNumInit);
74 43 }
75
76 1553 size_t size() const { return size_; }
77 10 size_t capacity() const { return capacity_; }
78
79 private:
80 static const size_t kNumInit = 64;
81 static const size_t kCompactThreshold = 64;
82
83 25006734 size_t GetHeadOffset() const { return head_ - buffer_; }
84 20004270 size_t GetAvailableSpace() const {
85 20004270 return capacity_ - (size_ + GetHeadOffset());
86 }
87
88 416 void Alloc(const size_t num_elements) {
89 416 size_t num_bytes = sizeof(Item) * num_elements;
90 416 buffer_ = static_cast<Item *>(smmap(num_bytes));
91 416 capacity_ = num_elements;
92 416 head_ = buffer_;
93 416 }
94
95 267 void Dealloc() {
96 267 FreeBuffer(buffer_, GetHeadOffset() + size_);
97 267 buffer_ = NULL;
98 267 head_ = NULL;
99 267 capacity_ = 0;
100 267 size_ = 0;
101 267 }
102
103 109 void Migrate(size_t new_capacity) {
104
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 109 assert(new_capacity > 0);
105
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 109 assert(new_capacity >= size_);
106
107 109 size_t head_offset = GetHeadOffset();
108 109 Item *old_buffer = buffer_;
109
110 109 Alloc(new_capacity);
111
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 56041012 for (size_t i = 0; i < size_; ++i)
112
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 56040903 new (buffer_ + i) Item(old_buffer[head_offset + i]);
113
114 109 FreeBuffer(old_buffer, head_offset + size_);
115 109 }
116
117 376 void FreeBuffer(Item *buf, const size_t nitems) {
118
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 81047539 for (size_t i = 0; i < nitems; ++i)
119 81047163 buf[i].~Item();
120
121
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 376 if (buf)
122 376 smunmap(buf);
123 376 }
124
125 44 void CopyFrom(const BigQueue<Item> &other) {
126 44 size_t min_items = kNumInit;
127 44 Alloc(std::max(other.size_, min_items));
128
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 5002132 for (size_t i = 0; i < other.size_; ++i) {
129
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 5002088 new (buffer_ + i) Item(*(other.buffer_ + other.GetHeadOffset() + i));
130 }
131 44 size_ = other.size_;
132 44 }
133
134 Item *buffer_;
135 Item *head_;
136 size_t size_;
137 size_t capacity_;
138 };
139
140 #endif // CVMFS_BIGQUEUE_H_
141