Here.cc
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1/*
2 * Copyright (C) 1996-2022 The Squid Software Foundation and contributors
3 *
4 * Squid software is distributed under GPLv2+ license and includes
5 * contributions from numerous individuals and organizations.
6 * Please see the COPYING and CONTRIBUTORS files for details.
7 */
8
9#include "squid.h"
10#include "base/Here.h"
11
12#include <iostream>
13
14/* File name hashing helpers */
15
16// Build prefix is the file system path leading to Squid src/ source directory.
17// It is "." for in-tree builds but may be lengthy and sensitive otherwise.
18
20static size_t
22{
23 // The hard-coded tail must be kept in sync with this file actual name!
24 const char *tail = "src/base/Here.cc";
25 const char *full = __FILE__;
26
27 // Disable heuristic if it does not work.
28 if (strstr(full, tail) == nullptr)
29 return 0;
30
31 return strlen(full) - strlen(tail);
32}
33
35static const char *
36SkipBuildPrefix(const char* path)
37{
38 static const size_t ToSkip = BuildPrefixLength();
39 return path + ToSkip;
40}
41
44FileNameHash(const char *path)
45{
46 // Keep in sync with FileNameHash() in scripts/calc-must-ids.pl!
47
48 const char *name = strrchr(path, '/');
49 if (name)
50 ++name; // skip '/'
51 else
52 name = path;
53
54 uint32_t hash = 0;
55 uint32_t iterations = 0;
56 while (*name) {
57 ++iterations;
58 hash ^= 271 * static_cast<uint32_t>(*name);
59 ++name;
60 }
61 return hash ^ (iterations * 271);
62}
63
64/* SourceLocation */
65
68{
69 const auto fnameHashFull = fileNameHashCacher(fileName, &FileNameHash);
70 // 32 bits = 18 bits for the filename hash + 14 bits for the line number.
71 // Keep in sync with ComputeMustIds() in scripts/calc-must-ids.pl.
72 const auto fnameHash = fnameHashFull % 0x3FFFF;
73 return (fnameHash << 14) | (lineNo & 0x3FFF);
74}
75
76std::ostream &
77SourceLocation::print(std::ostream &os) const
78{
79 if (fileName) {
81
82 // TODO: Use more common and search-friendlier fileName:lineNo: format.
83 if (lineNo > 0)
84 os << '(' << lineNo << ')';
85 }
86 if (context) {
87 if (fileName)
88 os << ' ';
89 os << context;
90 }
91 return os;
92}
93
static const char * SkipBuildPrefix(const char *path)
Definition: Here.cc:36
static size_t BuildPrefixLength()
Definition: Here.cc:21
static SourceLocationId FileNameHash(const char *path)
quickly computes a (weak) hash of a file name
Definition: Here.cc:44
uint32_t SourceLocationId
semi-uniquely identifies a source code location; stable across Squid runs
Definition: Here.h:18
const char * fileName
source file name, often relative to build path
Definition: Here.h:46
SourceLocationId id() const
Definition: Here.cc:67
int lineNo
line number inside the source file name (if positive)
Definition: Here.h:47
std::ostream & print(std::ostream &os) const
describes location using a compact but human-friendly format
Definition: Here.cc:77
const char * context
line-independent location description
Definition: Here.h:45
FileNameHashCacher * fileNameHashCacher
Definition: Here.h:51
static hash_table * hash
Definition: text_backend.cc:41

 

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