FileSystem Class Reference

Utility functions related to filename validation and filesystem access. More...

#include <FileSystem.h>

Classes
class	Lock
	Helper class for locking a file. More...
class	TemporaryFile
	Helper file to create a temporary file and ensure deletion if object goes out of scope. More...

Static Public Member Functions
static std::string	findFile (const std::string &path, bool silent=false)
	Search for given file or directory in local or central release directory, and return absolute path if found.
static std::string	findFile (const std::string &path, const std::string &dataType, bool silent=false)
	Search for given file or directory in the directory given by the environment variable BELLE2_<DATATYPE>_DATA_DIR or local/central release directory and return absolute path if found.
static bool	fileExists (const std::string &filename)
	Check if the file with given filename exists.
static bool	fileDirExists (const std::string &filename)
	Check if the dir containing the filename exists.
static bool	isFile (const std::string &filename)
	Check if filename points to an existing file.
static bool	isDir (const std::string &filename)
	Check if filename points to an existing directory.
static bool	isSymLink (const std::string &filename)
	Check if filename points to an existing symbolic link.
static std::string	calculateMD5 (const std::string &filename)
	Calculate the MD5 checksum of a given file.
static std::string	calculateAdler32 (const std::string &filename)
	Calculate the Adler-32 checksum of a given file.
static bool	loadLibrary (std::string library, bool fullname=true)
	Load a shared library.

Private Member Functions
	FileSystem ()=delete
	no instances.

Static Private Member Functions
static std::string	findFile (const std::string &path, const std::vector< std::string > &dirs, bool silent)
	Search for given file or directory in list of directories or working directory.

Detailed Description

Utility functions related to filename validation and filesystem access.

Definition at line 20 of file FileSystem.h.

Member Function Documentation

calculateAdler32()

std::string calculateAdler32 ( const std::string & filename )

static

Calculate the Adler-32 checksum of a given file.

Definition at line 86 of file FileSystem.cc.

{
  string chksum;
  if (not isFile(filename)) return "";
  fs::path fullPath = fs::absolute(filename);
  FILE* fp = fopen(fullPath.c_str(), "rb");
  if (fp) {
    uLong i, sum = adler32(0, 0, 0);
    char hexdigest[9];
    const size_t bufsize = 1024 * 1024 * sizeof(Bytef);
    Bytef* buf = (Bytef*) malloc(bufsize);
    if (!buf) {
      fclose(fp);
      return "";
    }
    while (true) {
      i = fread((void*) buf, 1, bufsize, fp);
      if (ferror(fp)) {
        free(buf);
        fclose(fp);
        return "";
      }
      if (i > 0) sum = adler32(sum, buf, i);
      if (feof(fp)) break;
    }
    fclose(fp);
    free(buf);
    // Adler32 checksums hex digests ARE zero padded although
    // HLT legacy presentation may differ.
    sprintf(hexdigest, "%08lx", sum);
    chksum = hexdigest;
  } else {
    chksum = "";
  }
  return chksum;
}

calculateMD5()

std::string calculateMD5 ( const std::string & filename )

static

Calculate the MD5 checksum of a given file.

Definition at line 78 of file FileSystem.cc.

{
  if (not isFile(filename)) return "";
  fs::path fullPath = fs::absolute(filename);
  std::unique_ptr<TMD5> md5(TMD5::FileChecksum(fullPath.c_str()));
  return md5->AsString();
}

fileDirExists()

bool fileDirExists ( const std::string & filename )

static

Check if the dir containing the filename exists.

Definition at line 38 of file FileSystem.cc.

{
  fs::path fullPath = fs::absolute(filename);
  fullPath.remove_filename();
  return fs::exists(fullPath);
}

fileExists()

bool fileExists ( const std::string & filename )

static

Check if the file with given filename exists.

Definition at line 32 of file FileSystem.cc.

{
  fs::path fullPath = fs::absolute(filename);
  return fs::exists(fullPath);
}

findFile() [1/3]

std::string findFile ( const std::string & path, bool silent = false )

static

Search for given file or directory in local or central release directory, and return absolute path if found.

If the file isn't found in either of these, absolute paths and paths relative to the current working directory are also accepted.

It is recommended to replace any relative paths you have with the return value of this function during initialization.

Parameters

path	path to file/directory, assuming it's installed locally (e.g. /data/geometry/Belle2.xml). Leading slash is not strictly required.
silent	If true, no error message is printed when file could not be found.

Returns

absolute path to file in local directory, if it exists, otherwise abs. path to file in central release directory, or empty string if file wasn't found.

Definition at line 159 of file FileSystem.cc.

{
  std::vector<std::string> dirs;
  if (getenv("BELLE2_LOCAL_DIR")) {
    dirs.emplace_back(getenv("BELLE2_LOCAL_DIR"));
  }
  if (getenv("BELLE2_RELEASE_DIR")) {
    dirs.emplace_back(getenv("BELLE2_RELEASE_DIR"));
  }
  return findFile(path, dirs, silent);
}

findFile() [2/3]

std::string findFile ( const std::string & path, const std::string & dataType, bool silent = false )

static

Search for given file or directory in the directory given by the environment variable BELLE2_<DATATYPE>_DATA_DIR or local/central release directory and return absolute path if found.

If the file isn't found in either of these, absolute paths and paths relative to the current working directory are also accepted.

It is recommended to replace any relative paths you have with the return value of this function during initialization.

Parameters

path	path to file/directory, assuming it's installed locally (e.g. /data/geometry/Belle2.xml). Leading slash is not strictly required.
dataType	type of data, like "examples", "validation" or "starterkit".
silent	If true, no error message is printed when file could not be found.

Returns

absolute path to file in local directory, if it exists, otherwise abs. path to file in central release directory, or empty string if file wasn't found.

Definition at line 171 of file FileSystem.cc.

{
  std::vector<std::string> dirs;
  std::string envVar = "BELLE2_" + boost::to_upper_copy(dataType) + "_DATA_DIR";
  if (getenv(envVar.c_str())) {
    dirs.emplace_back(getenv(envVar.c_str()));
  }
  std::string result = findFile(path, dirs, true);
  if (result.empty() && !silent)
    B2ERROR("findFile(): Could not find data file. You may want to use the 'b2install-data' tool to get the file."
            << LogVar("path", path) << LogVar("data type", dataType));
  return result;
}

findFile() [3/3]

std::string findFile ( const std::string & path, const std::vector< std::string > & dirs, bool silent )

staticprivate

Search for given file or directory in list of directories or working directory.

Definition at line 123 of file FileSystem.cc.

{
  // check given directories
  string fullpath;
  for (auto dir : dirs) {
    if (dir.empty())
      continue;
    fs::path dir_path = dir;
    if (fs::path(path).is_absolute())
      dir_path += path;
    else
      dir_path /= path;
    fullpath = dir_path.string();
    if (fileExists(fullpath)) {
      if (isSymLink(fullpath) or isSymLink(dir))
        return fullpath;
      else
        return fs::canonical(fullpath).string();
    }
  }
 
  // check local directory
  fullpath = fs::absolute(path).string();
  if (fileExists(fullpath)) {
    if (isSymLink(fullpath))
      return fullpath;
    else
      return fs::canonical(fullpath).string();
  }
 
  // nothing found
  if (!silent)
    B2ERROR("findFile(): Could not find file." << LogVar("path", path));
  return string("");
}

isDir()

bool isDir ( const std::string & filename )

static

Check if filename points to an existing directory.

Definition at line 51 of file FileSystem.cc.

{
  fs::path fullPath = fs::absolute(filename);
  return (fs::exists(fullPath)) && (fs::is_directory(fullPath));
}

isFile()

bool isFile ( const std::string & filename )

static

Check if filename points to an existing file.

Definition at line 45 of file FileSystem.cc.

{
  fs::path fullPath = fs::absolute(filename);
  return (fs::exists(fullPath)) && (fs::is_regular_file(fullPath));
}

isSymLink()

bool isSymLink ( const std::string & filename )

static

Check if filename points to an existing symbolic link.

Definition at line 57 of file FileSystem.cc.

{
  fs::path fullPath = fs::absolute(filename);
  return (fs::exists(fullPath)) && (fs::is_symlink(fullPath));
}

loadLibrary()

bool loadLibrary ( std::string library, bool fullname = true )

static

Load a shared library.

Symbols are resolved only when used, slightly reducing loading time (RTLD_LAZY, see dlopen(3))

Parameters

library	Name of the library
fullname	If false, the Library name is interpreted as short name like given to the compiler with -l. It will be expanded to lib<library>.so

Definition at line 63 of file FileSystem.cc.

{
  if (!fullname) library = "lib" + library + ".so";
 
  B2DEBUG(100, "Loading shared library " << library);
  void* libPointer = dlopen(library.c_str(), RTLD_LAZY | RTLD_GLOBAL);
 
  if (libPointer == nullptr) {
    B2ERROR("Could not open shared library file (error in dlopen) : " << dlerror());
    return false;
  }
 
  return true;
}

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The documentation for this class was generated from the following files:

• framework/utilities/include/FileSystem.h
• framework/utilities/src/FileSystem.cc