src/filesys.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "filesys.h"
  21 #include "util/string.h"
  22 #include <iostream>
  23 #include <cstdio>
  24 #include <cstring>
  25 #include <cerrno>
  26 #include <fstream>
  27 #include "log.h"
  28 #include "config.h"
  29 #include "porting.h"
  30 #ifdef __ANDROID__
  31 #include "settings.h" // For g_settings
  32 #endif
  33
  34 namespace fs
  35 {
  36
  37 #ifdef _WIN32 // WINDOWS
  38
  39 #define _WIN32_WINNT 0x0501
  40 #include <windows.h>
  41 #include <shlwapi.h>
  42
  43 std::vector<DirListNode> GetDirListing(const std::string &pathstring)
  44 {
  45         std::vector<DirListNode> listing;
  46
  47         WIN32_FIND_DATA FindFileData;
  48         HANDLE hFind = INVALID_HANDLE_VALUE;
  49         DWORD dwError;
  50
  51         std::string dirSpec = pathstring + "\\*";
  52
  53         // Find the first file in the directory.
  54         hFind = FindFirstFile(dirSpec.c_str(), &FindFileData);
  55
  56         if (hFind == INVALID_HANDLE_VALUE) {
  57                 dwError = GetLastError();
  58                 if (dwError != ERROR_FILE_NOT_FOUND && dwError != ERROR_PATH_NOT_FOUND) {
  59                         errorstream << "GetDirListing: FindFirstFile error."
  60                                         << " Error is " << dwError << std::endl;
  61                 }
  62         } else {
  63                 // NOTE:
  64                 // Be very sure to not include '..' in the results, it will
  65                 // result in an epic failure when deleting stuff.
  66
  67                 DirListNode node;
  68                 node.name = FindFileData.cFileName;
  69                 node.dir = FindFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
  70                 if (node.name != "." && node.name != "..")
  71                         listing.push_back(node);
  72
  73                 // List all the other files in the directory.
  74                 while (FindNextFile(hFind, &FindFileData) != 0) {
  75                         DirListNode node;
  76                         node.name = FindFileData.cFileName;
  77                         node.dir = FindFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
  78                         if(node.name != "." && node.name != "..")
  79                                 listing.push_back(node);
  80                 }
  81
  82                 dwError = GetLastError();
  83                 FindClose(hFind);
  84                 if (dwError != ERROR_NO_MORE_FILES) {
  85                         errorstream << "GetDirListing: FindNextFile error."
  86                                         << " Error is " << dwError << std::endl;
  87                         listing.clear();
  88                         return listing;
  89                 }
  90         }
  91         return listing;
  92 }
  93
  94 bool CreateDir(const std::string &path)
  95 {
  96         bool r = CreateDirectory(path.c_str(), NULL);
  97         if(r == true)
  98                 return true;
  99         if(GetLastError() == ERROR_ALREADY_EXISTS)
 100                 return true;
 101         return false;
 102 }
 103
 104 bool PathExists(const std::string &path)
 105 {
 106         return (GetFileAttributes(path.c_str()) != INVALID_FILE_ATTRIBUTES);
 107 }
 108
 109 bool IsPathAbsolute(const std::string &path)
 110 {
 111         return !PathIsRelative(path.c_str());
 112 }
 113
 114 bool IsDir(const std::string &path)
 115 {
 116         DWORD attr = GetFileAttributes(path.c_str());
 117         return (attr != INVALID_FILE_ATTRIBUTES &&
 118                         (attr & FILE_ATTRIBUTE_DIRECTORY));
 119 }
 120
 121 bool IsDirDelimiter(char c)
 122 {
 123         return c == '/' || c == '\\';
 124 }
 125
 126 bool RecursiveDelete(const std::string &path)
 127 {
 128         infostream << "Recursively deleting \"" << path << "\"" << std::endl;
 129         if (!IsDir(path)) {
 130                 infostream << "RecursiveDelete: Deleting file  " << path << std::endl;
 131                 if (!DeleteFile(path.c_str())) {
 132                         errorstream << "RecursiveDelete: Failed to delete file "
 133                                         << path << std::endl;
 134                         return false;
 135                 }
 136                 return true;
 137         }
 138         infostream << "RecursiveDelete: Deleting content of directory "
 139                         << path << std::endl;
 140         std::vector<DirListNode> content = GetDirListing(path);
 141         for (const DirListNode &n: content) {
 142                 std::string fullpath = path + DIR_DELIM + n.name;
 143                 if (!RecursiveDelete(fullpath)) {
 144                         errorstream << "RecursiveDelete: Failed to recurse to "
 145                                         << fullpath << std::endl;
 146                         return false;
 147                 }
 148         }
 149         infostream << "RecursiveDelete: Deleting directory " << path << std::endl;
 150         if (!RemoveDirectory(path.c_str())) {
 151                 errorstream << "Failed to recursively delete directory "
 152                                 << path << std::endl;
 153                 return false;
 154         }
 155         return true;
 156 }
 157
 158 bool DeleteSingleFileOrEmptyDirectory(const std::string &path)
 159 {
 160         DWORD attr = GetFileAttributes(path.c_str());
 161         bool is_directory = (attr != INVALID_FILE_ATTRIBUTES &&
 162                         (attr & FILE_ATTRIBUTE_DIRECTORY));
 163         if(!is_directory)
 164         {
 165                 bool did = DeleteFile(path.c_str());
 166                 return did;
 167         }
 168         else
 169         {
 170                 bool did = RemoveDirectory(path.c_str());
 171                 return did;
 172         }
 173 }
 174
 175 std::string TempPath()
 176 {
 177         DWORD bufsize = GetTempPath(0, NULL);
 178         if(bufsize == 0){
 179                 errorstream<<"GetTempPath failed, error = "<<GetLastError()<<std::endl;
 180                 return "";
 181         }
 182         std::vector<char> buf(bufsize);
 183         DWORD len = GetTempPath(bufsize, &buf[0]);
 184         if(len == 0 || len > bufsize){
 185                 errorstream<<"GetTempPath failed, error = "<<GetLastError()<<std::endl;
 186                 return "";
 187         }
 188         return std::string(buf.begin(), buf.begin() + len);
 189 }
 190
 191 #else // POSIX
 192
 193 #include <sys/types.h>
 194 #include <dirent.h>
 195 #include <sys/stat.h>
 196 #include <sys/wait.h>
 197 #include <unistd.h>
 198
 199 std::vector<DirListNode> GetDirListing(const std::string &pathstring)
 200 {
 201         std::vector<DirListNode> listing;
 202
 203         DIR *dp;
 204         struct dirent *dirp;
 205         if((dp = opendir(pathstring.c_str())) == NULL) {
 206                 //infostream<<"Error("<<errno<<") opening "<<pathstring<<std::endl;
 207                 return listing;
 208         }
 209
 210         while ((dirp = readdir(dp)) != NULL) {
 211                 // NOTE:
 212                 // Be very sure to not include '..' in the results, it will
 213                 // result in an epic failure when deleting stuff.
 214                 if(strcmp(dirp->d_name, ".") == 0 || strcmp(dirp->d_name, "..") == 0)
 215                         continue;
 216
 217                 DirListNode node;
 218                 node.name = dirp->d_name;
 219
 220                 int isdir = -1; // -1 means unknown
 221
 222                 /*
 223                         POSIX doesn't define d_type member of struct dirent and
 224                         certain filesystems on glibc/Linux will only return
 225                         DT_UNKNOWN for the d_type member.
 226
 227                         Also we don't know whether symlinks are directories or not.
 228                 */
 229 #ifdef _DIRENT_HAVE_D_TYPE
 230                 if(dirp->d_type != DT_UNKNOWN && dirp->d_type != DT_LNK)
 231                         isdir = (dirp->d_type == DT_DIR);
 232 #endif /* _DIRENT_HAVE_D_TYPE */
 233
 234                 /*
 235                         Was d_type DT_UNKNOWN, DT_LNK or nonexistent?
 236                         If so, try stat().
 237                 */
 238                 if(isdir == -1) {
 239                         struct stat statbuf{};
 240                         if (stat((pathstring + "/" + node.name).c_str(), &statbuf))
 241                                 continue;
 242                         isdir = ((statbuf.st_mode & S_IFDIR) == S_IFDIR);
 243                 }
 244                 node.dir = isdir;
 245                 listing.push_back(node);
 246         }
 247         closedir(dp);
 248
 249         return listing;
 250 }
 251
 252 bool CreateDir(const std::string &path)
 253 {
 254         int r = mkdir(path.c_str(), S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
 255         if (r == 0) {
 256                 return true;
 257         }
 258
 259         // If already exists, return true
 260         if (errno == EEXIST)
 261                 return true;
 262         return false;
 263
 264 }
 265
 266 bool PathExists(const std::string &path)
 267 {
 268         struct stat st{};
 269         return (stat(path.c_str(),&st) == 0);
 270 }
 271
 272 bool IsPathAbsolute(const std::string &path)
 273 {
 274         return path[0] == '/';
 275 }
 276
 277 bool IsDir(const std::string &path)
 278 {
 279         struct stat statbuf{};
 280         if(stat(path.c_str(), &statbuf))
 281                 return false; // Actually error; but certainly not a directory
 282         return ((statbuf.st_mode & S_IFDIR) == S_IFDIR);
 283 }
 284
 285 bool IsDirDelimiter(char c)
 286 {
 287         return c == '/';
 288 }
 289
 290 bool RecursiveDelete(const std::string &path)
 291 {
 292         /*
 293                 Execute the 'rm' command directly, by fork() and execve()
 294         */
 295
 296         infostream<<"Removing \""<<path<<"\""<<std::endl;
 297
 298         //return false;
 299
 300         pid_t child_pid = fork();
 301
 302         if(child_pid == 0)
 303         {
 304                 // Child
 305                 char argv_data[3][10000];
 306 #ifdef __ANDROID__
 307                 strcpy(argv_data[0], "/system/bin/rm");
 308 #else
 309                 strcpy(argv_data[0], "/bin/rm");
 310 #endif
 311                 strcpy(argv_data[1], "-rf");
 312                 strncpy(argv_data[2], path.c_str(), 10000);
 313                 char *argv[4];
 314                 argv[0] = argv_data[0];
 315                 argv[1] = argv_data[1];
 316                 argv[2] = argv_data[2];
 317                 argv[3] = NULL;
 318
 319                 verbosestream<<"Executing '"<<argv[0]<<"' '"<<argv[1]<<"' '"
 320                                 <<argv[2]<<"'"<<std::endl;
 321
 322                 execv(argv[0], argv);
 323
 324                 // Execv shouldn't return. Failed.
 325                 _exit(1);
 326         }
 327         else
 328         {
 329                 // Parent
 330                 int child_status;
 331                 pid_t tpid;
 332                 do{
 333                         tpid = wait(&child_status);
 334                         //if(tpid != child_pid) process_terminated(tpid);
 335                 }while(tpid != child_pid);
 336                 return (child_status == 0);
 337         }
 338 }
 339
 340 bool DeleteSingleFileOrEmptyDirectory(const std::string &path)
 341 {
 342         if (IsDir(path)) {
 343                 bool did = (rmdir(path.c_str()) == 0);
 344                 if (!did)
 345                         errorstream << "rmdir errno: " << errno << ": " << strerror(errno)
 346                                         << std::endl;
 347                 return did;
 348         }
 349
 350         bool did = (unlink(path.c_str()) == 0);
 351         if (!did)
 352                 errorstream << "unlink errno: " << errno << ": " << strerror(errno)
 353                                 << std::endl;
 354         return did;
 355 }
 356
 357 std::string TempPath()
 358 {
 359         /*
 360                 Should the environment variables TMPDIR, TMP and TEMP
 361                 and the macro P_tmpdir (if defined by stdio.h) be checked
 362                 before falling back on /tmp?
 363
 364                 Probably not, because this function is intended to be
 365                 compatible with lua's os.tmpname which under the default
 366                 configuration hardcodes mkstemp("/tmp/lua_XXXXXX").
 367         */
 368 #ifdef __ANDROID__
 369         return g_settings->get("TMPFolder");
 370 #else
 371         return DIR_DELIM "tmp";
 372 #endif
 373 }
 374
 375 #endif
 376
 377 void GetRecursiveDirs(std::vector<std::string> &dirs, const std::string &dir)
 378 {
 379         static const std::set<char> chars_to_ignore = { '_', '.' };
 380         if (dir.empty() || !IsDir(dir))
 381                 return;
 382         dirs.push_back(dir);
 383         fs::GetRecursiveSubPaths(dir, dirs, false, chars_to_ignore);
 384 }
 385
 386 std::vector<std::string> GetRecursiveDirs(const std::string &dir)
 387 {
 388         std::vector<std::string> result;
 389         GetRecursiveDirs(result, dir);
 390         return result;
 391 }
 392
 393 void GetRecursiveSubPaths(const std::string &path,
 394                   std::vector<std::string> &dst,
 395                   bool list_files,
 396                   const std::set<char> &ignore)
 397 {
 398         std::vector<DirListNode> content = GetDirListing(path);
 399         for (const auto &n : content) {
 400                 std::string fullpath = path + DIR_DELIM + n.name;
 401                 if (ignore.count(n.name[0]))
 402                         continue;
 403                 if (list_files || n.dir)
 404                         dst.push_back(fullpath);
 405                 if (n.dir)
 406                         GetRecursiveSubPaths(fullpath, dst, list_files, ignore);
 407         }
 408 }
 409
 410 bool DeletePaths(const std::vector<std::string> &paths)
 411 {
 412         bool success = true;
 413         // Go backwards to succesfully delete the output of GetRecursiveSubPaths
 414         for(int i=paths.size()-1; i>=0; i--){
 415                 const std::string &path = paths[i];
 416                 bool did = DeleteSingleFileOrEmptyDirectory(path);
 417                 if(!did){
 418                         errorstream<<"Failed to delete "<<path<<std::endl;
 419                         success = false;
 420                 }
 421         }
 422         return success;
 423 }
 424
 425 bool RecursiveDeleteContent(const std::string &path)
 426 {
 427         infostream<<"Removing content of \""<<path<<"\""<<std::endl;
 428         std::vector<DirListNode> list = GetDirListing(path);
 429         for (const DirListNode &dln : list) {
 430                 if(trim(dln.name) == "." || trim(dln.name) == "..")
 431                         continue;
 432                 std::string childpath = path + DIR_DELIM + dln.name;
 433                 bool r = RecursiveDelete(childpath);
 434                 if(!r) {
 435                         errorstream << "Removing \"" << childpath << "\" failed" << std::endl;
 436                         return false;
 437                 }
 438         }
 439         return true;
 440 }
 441
 442 bool CreateAllDirs(const std::string &path)
 443 {
 444
 445         std::vector<std::string> tocreate;
 446         std::string basepath = path;
 447         while(!PathExists(basepath))
 448         {
 449                 tocreate.push_back(basepath);
 450                 basepath = RemoveLastPathComponent(basepath);
 451                 if(basepath.empty())
 452                         break;
 453         }
 454         for(int i=tocreate.size()-1;i>=0;i--)
 455                 if(!CreateDir(tocreate[i]))
 456                         return false;
 457         return true;
 458 }
 459
 460 bool CopyFileContents(const std::string &source, const std::string &target)
 461 {
 462         FILE *sourcefile = fopen(source.c_str(), "rb");
 463         if(sourcefile == NULL){
 464                 errorstream<<source<<": can't open for reading: "
 465                         <<strerror(errno)<<std::endl;
 466                 return false;
 467         }
 468
 469         FILE *targetfile = fopen(target.c_str(), "wb");
 470         if(targetfile == NULL){
 471                 errorstream<<target<<": can't open for writing: "
 472                         <<strerror(errno)<<std::endl;
 473                 fclose(sourcefile);
 474                 return false;
 475         }
 476
 477         size_t total = 0;
 478         bool retval = true;
 479         bool done = false;
 480         char readbuffer[BUFSIZ];
 481         while(!done){
 482                 size_t readbytes = fread(readbuffer, 1,
 483                                 sizeof(readbuffer), sourcefile);
 484                 total += readbytes;
 485                 if(ferror(sourcefile)){
 486                         errorstream<<source<<": IO error: "
 487                                 <<strerror(errno)<<std::endl;
 488                         retval = false;
 489                         done = true;
 490                 }
 491                 if(readbytes > 0){
 492                         fwrite(readbuffer, 1, readbytes, targetfile);
 493                 }
 494                 if(feof(sourcefile) || ferror(sourcefile)){
 495                         // flush destination file to catch write errors
 496                         // (e.g. disk full)
 497                         fflush(targetfile);
 498                         done = true;
 499                 }
 500                 if(ferror(targetfile)){
 501                         errorstream<<target<<": IO error: "
 502                                         <<strerror(errno)<<std::endl;
 503                         retval = false;
 504                         done = true;
 505                 }
 506         }
 507         infostream<<"copied "<<total<<" bytes from "
 508                 <<source<<" to "<<target<<std::endl;
 509         fclose(sourcefile);
 510         fclose(targetfile);
 511         return retval;
 512 }
 513
 514 bool CopyDir(const std::string &source, const std::string &target)
 515 {
 516         if(PathExists(source)){
 517                 if(!PathExists(target)){
 518                         fs::CreateAllDirs(target);
 519                 }
 520                 bool retval = true;
 521                 std::vector<DirListNode> content = fs::GetDirListing(source);
 522
 523                 for (const auto &dln : content) {
 524                         std::string sourcechild = source + DIR_DELIM + dln.name;
 525                         std::string targetchild = target + DIR_DELIM + dln.name;
 526                         if(dln.dir){
 527                                 if(!fs::CopyDir(sourcechild, targetchild)){
 528                                         retval = false;
 529                                 }
 530                         }
 531                         else {
 532                                 if(!fs::CopyFileContents(sourcechild, targetchild)){
 533                                         retval = false;
 534                                 }
 535                         }
 536                 }
 537                 return retval;
 538         }
 539
 540         return false;
 541 }
 542
 543 bool PathStartsWith(const std::string &path, const std::string &prefix)
 544 {
 545         size_t pathsize = path.size();
 546         size_t pathpos = 0;
 547         size_t prefixsize = prefix.size();
 548         size_t prefixpos = 0;
 549         for(;;){
 550                 bool delim1 = pathpos == pathsize
 551                         || IsDirDelimiter(path[pathpos]);
 552                 bool delim2 = prefixpos == prefixsize
 553                         || IsDirDelimiter(prefix[prefixpos]);
 554
 555                 if(delim1 != delim2)
 556                         return false;
 557
 558                 if(delim1){
 559                         while(pathpos < pathsize &&
 560                                         IsDirDelimiter(path[pathpos]))
 561                                 ++pathpos;
 562                         while(prefixpos < prefixsize &&
 563                                         IsDirDelimiter(prefix[prefixpos]))
 564                                 ++prefixpos;
 565                         if(prefixpos == prefixsize)
 566                                 return true;
 567                         if(pathpos == pathsize)
 568                                 return false;
 569                 }
 570                 else{
 571                         size_t len = 0;
 572                         do{
 573                                 char pathchar = path[pathpos+len];
 574                                 char prefixchar = prefix[prefixpos+len];
 575                                 if(FILESYS_CASE_INSENSITIVE){
 576                                         pathchar = tolower(pathchar);
 577                                         prefixchar = tolower(prefixchar);
 578                                 }
 579                                 if(pathchar != prefixchar)
 580                                         return false;
 581                                 ++len;
 582                         } while(pathpos+len < pathsize
 583                                         && !IsDirDelimiter(path[pathpos+len])
 584                                         && prefixpos+len < prefixsize
 585                                         && !IsDirDelimiter(
 586                                                 prefix[prefixpos+len]));
 587                         pathpos += len;
 588                         prefixpos += len;
 589                 }
 590         }
 591 }
 592
 593 std::string RemoveLastPathComponent(const std::string &path,
 594                 std::string *removed, int count)
 595 {
 596         if(removed)
 597                 *removed = "";
 598
 599         size_t remaining = path.size();
 600
 601         for(int i = 0; i < count; ++i){
 602                 // strip a dir delimiter
 603                 while(remaining != 0 && IsDirDelimiter(path[remaining-1]))
 604                         remaining--;
 605                 // strip a path component
 606                 size_t component_end = remaining;
 607                 while(remaining != 0 && !IsDirDelimiter(path[remaining-1]))
 608                         remaining--;
 609                 size_t component_start = remaining;
 610                 // strip a dir delimiter
 611                 while(remaining != 0 && IsDirDelimiter(path[remaining-1]))
 612                         remaining--;
 613                 if(removed){
 614                         std::string component = path.substr(component_start,
 615                                         component_end - component_start);
 616                         if(i)
 617                                 *removed = component + DIR_DELIM + *removed;
 618                         else
 619                                 *removed = component;
 620                 }
 621         }
 622         return path.substr(0, remaining);
 623 }
 624
 625 std::string RemoveRelativePathComponents(std::string path)
 626 {
 627         size_t pos = path.size();
 628         size_t dotdot_count = 0;
 629         while (pos != 0) {
 630                 size_t component_with_delim_end = pos;
 631                 // skip a dir delimiter
 632                 while (pos != 0 && IsDirDelimiter(path[pos-1]))
 633                         pos--;
 634                 // strip a path component
 635                 size_t component_end = pos;
 636                 while (pos != 0 && !IsDirDelimiter(path[pos-1]))
 637                         pos--;
 638                 size_t component_start = pos;
 639
 640                 std::string component = path.substr(component_start,
 641                                 component_end - component_start);
 642                 bool remove_this_component = false;
 643                 if (component == ".") {
 644                         remove_this_component = true;
 645                 } else if (component == "..") {
 646                         remove_this_component = true;
 647                         dotdot_count += 1;
 648                 } else if (dotdot_count != 0) {
 649                         remove_this_component = true;
 650                         dotdot_count -= 1;
 651                 }
 652
 653                 if (remove_this_component) {
 654                         while (pos != 0 && IsDirDelimiter(path[pos-1]))
 655                                 pos--;
 656                         if (component_start == 0) {
 657                                 // We need to remove the delemiter too
 658                                 path = path.substr(component_with_delim_end, std::string::npos);
 659                         } else {
 660                                 path = path.substr(0, pos) + DIR_DELIM +
 661                                         path.substr(component_with_delim_end, std::string::npos);
 662                         }
 663                         if (pos > 0)
 664                                 pos++;
 665                 }
 666         }
 667
 668         if (dotdot_count > 0)
 669                 return "";
 670
 671         // remove trailing dir delimiters
 672         pos = path.size();
 673         while (pos != 0 && IsDirDelimiter(path[pos-1]))
 674                 pos--;
 675         return path.substr(0, pos);
 676 }
 677
 678 std::string AbsolutePath(const std::string &path)
 679 {
 680 #ifdef _WIN32
 681         char *abs_path = _fullpath(NULL, path.c_str(), MAX_PATH);
 682 #else
 683         char *abs_path = realpath(path.c_str(), NULL);
 684 #endif
 685         if (!abs_path) return "";
 686         std::string abs_path_str(abs_path);
 687         free(abs_path);
 688         return abs_path_str;
 689 }
 690
 691 const char *GetFilenameFromPath(const char *path)
 692 {
 693         const char *filename = strrchr(path, DIR_DELIM_CHAR);
 694         return filename ? filename + 1 : path;
 695 }
 696
 697 bool safeWriteToFile(const std::string &path, const std::string &content)
 698 {
 699         std::string tmp_file = path + ".~mt";
 700
 701         // Write to a tmp file
 702         std::ofstream os(tmp_file.c_str(), std::ios::binary);
 703         if (!os.good())
 704                 return false;
 705         os << content;
 706         os.flush();
 707         os.close();
 708         if (os.fail()) {
 709                 // Remove the temporary file because writing it failed and it's useless.
 710                 remove(tmp_file.c_str());
 711                 return false;
 712         }
 713
 714         bool rename_success = false;
 715
 716         // Move the finished temporary file over the real file
 717 #ifdef _WIN32
 718         // When creating the file, it can cause Windows Search indexer, virus scanners and other apps
 719         // to query the file. This can make the move file call below fail.
 720         // We retry up to 5 times, with a 1ms sleep between, before we consider the whole operation failed
 721         int number_attempts = 0;
 722         while (number_attempts < 5) {
 723                 rename_success = MoveFileEx(tmp_file.c_str(), path.c_str(),
 724                                 MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH);
 725                 if (rename_success)
 726                         break;
 727                 sleep_ms(1);
 728                 ++number_attempts;
 729         }
 730 #else
 731         // On POSIX compliant systems rename() is specified to be able to swap the
 732         // file in place of the destination file, making this a truly error-proof
 733         // transaction.
 734         rename_success = rename(tmp_file.c_str(), path.c_str()) == 0;
 735 #endif
 736         if (!rename_success) {
 737                 warningstream << "Failed to write to file: " << path.c_str() << std::endl;
 738                 // Remove the temporary file because moving it over the target file
 739                 // failed.
 740                 remove(tmp_file.c_str());
 741                 return false;
 742         }
 743
 744         return true;
 745 }
 746
 747 bool Rename(const std::string &from, const std::string &to)
 748 {
 749         return rename(from.c_str(), to.c_str()) == 0;
 750 }
 751
 752 } // namespace fs
 753