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//
// Copyright (c) 2009-2011 Artyom Beilis (Tonkikh)
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
#define BOOST_LOCALE_SOURCE
#include "time_zone.hpp"
//
// Bug - when ICU tries to find a file that is equivalent to /etc/localtime it finds /usr/share/zoneinfo/localtime
// that is just a symbolic link to /etc/localtime.
//
// It started in 4.0 and was fixed in version 4.6, also the fix was backported to the 4.4 branch so it should be
// available from 4.4.3... So we test if the workaround is required
//
// It is also relevant only for Linux, BSD and Apple (as I see in ICU code)
//
#if U_ICU_VERSION_MAJOR_NUM == 4 && (U_ICU_VERSION_MINOR_NUM * 100 + U_ICU_VERSION_PATCHLEVEL_NUM) <= 402
# if defined(__linux) || defined(__FreeBSD__) || defined(__APPLE__)
# define BOOST_LOCALE_WORKAROUND_ICU_BUG
# endif
#endif
#ifdef BOOST_LOCALE_WORKAROUND_ICU_BUG
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fstream>
#include <pthread.h>
#include <string.h>
#include <memory>
#endif
#include <boost/locale/hold_ptr.hpp>
namespace boost {
namespace locale {
namespace impl_icu {
#ifndef BOOST_LOCALE_WORKAROUND_ICU_BUG
// This is normal behavior
icu::TimeZone *get_time_zone(std::string const &time_zone)
{
if(time_zone.empty()) {
return icu::TimeZone::createDefault();
}
else {
return icu::TimeZone::createTimeZone(time_zone.c_str());
}
}
#else
//
// This is a workaround for an ICU timezone detection bug.
// It is \b very ICU specific and should not be used
// in general. It is also designed to work only on
// specific patforms: Linux, BSD and Apple, where this bug may actually
// occur
//
namespace {
// Under BSD, Linux and Mac OS X dirent has normal size
// so no issues with readdir_r
class directory {
public:
directory(char const *name) : d(0),read_result(0)
{
d=opendir(name);
if(!d)
return;
}
~directory()
{
if(d)
closedir(d);
}
bool is_open()
{
return d;
}
char const *next()
{
if(d && readdir_r(d,&de,&read_result)==0 && read_result!=0)
return de.d_name;
return 0;
}
private:
DIR *d;
struct dirent de;
struct dirent *read_result;
};
bool files_equal(std::string const &left,std::string const &right)
{
char l[256],r[256];
std::ifstream ls(left.c_str());
if(!ls)
return false;
std::ifstream rs(right.c_str());
if(!rs)
return false;
do {
ls.read(l,sizeof(l));
rs.read(r,sizeof(r));
size_t n;
if((n=ls.gcount())!=size_t(rs.gcount()))
return false;
if(memcmp(l,r,n)!=0)
return false;
}while(!ls.eof() || !rs.eof());
if(bool(ls.eof())!=bool(rs.eof()))
return false;
return true;
}
std::string find_file_in(std::string const &ref,size_t size,std::string const &dir)
{
directory d(dir.c_str());
if(!d.is_open())
return std::string();
char const *name=0;
while((name=d.next())!=0) {
std::string file_name = name;
if( file_name == "."
|| file_name ==".."
|| file_name=="posixrules"
|| file_name=="localtime")
{
continue;
}
struct stat st;
std::string path = dir+"/"+file_name;
if(stat(path.c_str(),&st)==0) {
if(S_ISDIR(st.st_mode)) {
std::string res = find_file_in(ref,size,path);
if(!res.empty())
return file_name + "/" + res;
}
else {
if(size_t(st.st_size) == size && files_equal(path,ref)) {
return file_name;
}
}
}
}
return std::string();
}
// This actually emulates ICU's search
// algorithm... just it ignores localtime
std::string detect_correct_time_zone()
{
char const *tz_dir = "/usr/share/zoneinfo";
char const *tz_file = "/etc/localtime";
struct stat st;
if(::stat(tz_file,&st)!=0)
return std::string();
size_t size = st.st_size;
std::string r = find_file_in(tz_file,size,tz_dir);
if(r.empty())
return r;
if(r.compare(0,6,"posix/")==0 || r.compare(0,6,"right/",6)==0)
return r.substr(6);
return r;
}
//
// Using pthread as:
// - This bug is relevant for only Linux, BSD, Mac OS X and
// pthreads are native threading API
// - The dependency on boost.thread may be removed when using
// more recent ICU versions (so TLS would not be needed)
//
// This the dependency on Boost.Thread is eliminated
//
pthread_once_t init_tz = PTHREAD_ONCE_INIT;
std::string default_time_zone_name;
extern "C" {
static void init_tz_proc()
{
try {
default_time_zone_name = detect_correct_time_zone();
}
catch(...){}
}
}
std::string get_time_zone_name()
{
pthread_once(&init_tz,init_tz_proc);
return default_time_zone_name;
}
} // namespace
icu::TimeZone *get_time_zone(std::string const &time_zone)
{
if(!time_zone.empty()) {
return icu::TimeZone::createTimeZone(time_zone.c_str());
}
hold_ptr<icu::TimeZone> tz(icu::TimeZone::createDefault());
icu::UnicodeString id;
tz->getID(id);
// Check if there is a bug?
if(id != icu::UnicodeString("localtime"))
return tz.release();
// Now let's deal with the bug and run the fixed
// search loop as that of ICU
std::string real_id = get_time_zone_name();
if(real_id.empty()) {
// if we failed fallback to ICU's time zone
return tz.release();
}
return icu::TimeZone::createTimeZone(real_id.c_str());
}
#endif // bug workaround
}
}
}
// vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
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