Here.h

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/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
#ifndef SQUID_BASE_HERE_H
#define SQUID_BASE_HERE_H
 
#include <iosfwd>
 
#define Here() SourceLocation(__FUNCTION__, __FILE__, __LINE__)
 
typedef uint32_t SourceLocationId;
 
typedef SourceLocationId FileNameHasher(const char *fileName);
 
typedef SourceLocationId FileNameHashCacher(const char *fileName, FileNameHasher hasher);
 
static FileNameHashCacher UnitFileNameHashCacher;
 
class SourceLocation
{
public:
    SourceLocation(const char *aContext, const char *aFileName, const int aLineNo):
        context(aContext),
        fileName(aFileName),
        lineNo(aLineNo),
        fileNameHashCacher(&UnitFileNameHashCacher)
    {}
 
    SourceLocationId id() const;
 
    std::ostream &print(std::ostream &os) const;
 
    const char *context; 
    const char *fileName; 
    int lineNo; 
 
private:
    SourceLocationId calculateId(FileNameHasher) const;
    FileNameHashCacher *fileNameHashCacher;
};
 
inline std::ostream &
operator <<(std::ostream &os, const SourceLocation &location)
{
    return location.print(os);
}
 
static SourceLocationId
UnitFileNameHashCacher(const char *fileName, FileNameHasher hasher)
{
    static SourceLocationId cachedHash = 0;
    static const char *hashedFilename = nullptr;
    // Each file #included in a translation unit has its own __FILE__ value.
    // Keep the cache fresh (and the result correct).
    if (hashedFilename != fileName) { // cheap pointer comparison
        hashedFilename = fileName;
        cachedHash = hasher(fileName);
    }
    return cachedHash;
}
 
#endif