gflags.cc

  string msg;
  vector<string> filename_list;
  ParseFlagList(flagval.c_str(), &filename_list);  // take a list of filenames
  for (int i = 0; i < filename_list.size(); ++i) {
    const char* file = filename_list[i].c_str();
    msg += ProcessOptionsFromStringLocked(ReadFileIntoString(file), set_mode);
  }
  return msg;
}

string CommandLineFlagParser::ProcessFromenvLocked(const string& flagval,
                                                   FlagSettingMode set_mode,
                                                   bool errors_are_fatal) {
  if (flagval.empty())
    return "";

  string msg;
  vector<string> flaglist;
  ParseFlagList(flagval.c_str(), &flaglist);

  for (int i = 0; i < flaglist.size(); ++i) {
    const char* flagname = flaglist[i].c_str();
    CommandLineFlag* flag = registry_->FindFlagLocked(flagname);
    if (flag == NULL) {
      error_flags_[flagname] = (string(kError) + "unknown command line flag"
                                + " '" + flagname + "'"
                                + " (via --fromenv or --tryfromenv)\n");
      undefined_names_[flagname] = "";
      continue;
    }

    const string envname = string("FLAGS_") + string(flagname);
    const char* envval = getenv(envname.c_str());
    if (!envval) {
      if (errors_are_fatal) {
        error_flags_[flagname] = (string(kError) + envname +
                                  " not found in environment\n");
      }
      continue;
    }

    // Avoid infinite recursion.
    if ((strcmp(envval, "fromenv") == 0) ||
        (strcmp(envval, "tryfromenv") == 0)) {
      error_flags_[flagname] = (string(kError) + "infinite recursion on " +
                                "environment flag '" + envval + "'\n");
      continue;
    }

    msg += ProcessSingleOptionLocked(flag, envval, set_mode);
  }
  return msg;
}

string CommandLineFlagParser::ProcessSingleOptionLocked(
    CommandLineFlag* flag, const char* value, FlagSettingMode set_mode) {
  string msg;
  if (value && !registry_->SetFlagLocked(flag, value, set_mode, &msg)) {
    error_flags_[flag->name()] = msg;
    return "";
  }

  // The recursive flags, --flagfile and --fromenv and --tryfromenv,
  // must be dealt with as soon as they're seen.  They will emit
  // messages of their own.
  if (strcmp(flag->name(), "flagfile") == 0) {
    msg += ProcessFlagfileLocked(FLAGS_flagfile, set_mode);

  } else if (strcmp(flag->name(), "fromenv") == 0) {
    // last arg indicates envval-not-found is fatal (unlike in --tryfromenv)
    msg += ProcessFromenvLocked(FLAGS_fromenv, set_mode, true);

  } else if (strcmp(flag->name(), "tryfromenv") == 0) {
    msg += ProcessFromenvLocked(FLAGS_tryfromenv, set_mode, false);

  }

  return msg;
}

bool CommandLineFlagParser::ReportErrors() {
  // error_flags_ indicates errors we saw while parsing.
  // But we ignore undefined-names if ok'ed by --undef_ok
  if (!FLAGS_undefok.empty()) {
    vector<string> flaglist;
    ParseFlagList(FLAGS_undefok.c_str(), &flaglist);
    for (int i = 0; i < flaglist.size(); ++i)
      if (undefined_names_.find(flaglist[i]) != undefined_names_.end()) {
        error_flags_[flaglist[i]] = "";    // clear the error message
      }
  }
  // Likewise, if they decided to allow reparsing, all undefined-names
  // are ok; we just silently ignore them now, and hope that a future
  // parse will pick them up somehow.
  if (allow_command_line_reparsing) {
    for (map<string,string>::const_iterator it = undefined_names_.begin();
         it != undefined_names_.end();  ++it)
      error_flags_[it->first] = "";      // clear the error message
  }

  bool found_error = false;
  for (map<string,string>::const_iterator it = error_flags_.begin();
       it != error_flags_.end(); ++it) {
    if (!it->second.empty()) {
      fprintf(stderr, "%s", it->second.c_str());
      found_error = true;
    }
  }
  return found_error;
}

string CommandLineFlagParser::ProcessOptionsFromStringLocked(
    const string& contentdata, FlagSettingMode set_mode) {
  string retval;
  const char* flagfile_contents = contentdata.c_str();
  bool flags_are_relevant = true;   // set to false when filenames don't match
  bool in_filename_section = false;

  const char* line_end = flagfile_contents;
  // We read this file a line at a time.
  for (; line_end; flagfile_contents = line_end + 1) {
    while (*flagfile_contents && isspace(*flagfile_contents))
      ++flagfile_contents;
    line_end = strchr(flagfile_contents, '\n');
    int len = line_end ? line_end-flagfile_contents : strlen(flagfile_contents);
    string line(flagfile_contents, len);

    // Each line can be one of four things:
    // 1) A comment line -- we skip it
    // 2) An empty line -- we skip it
    // 3) A list of filenames -- starts a new filenames+flags section
    // 4) A --flag=value line -- apply if previous filenames match
    if (line.empty() || line[0] == '#') {
      // comment or empty line; just ignore

    } else if (line[0] == '-') {    // flag
      in_filename_section = false;  // instead, it was a flag-line
      if (!flags_are_relevant)      // skip this flag; applies to someone else
        continue;

      const char* name_and_val = line.c_str() + 1;    // skip the leading -
      if (*name_and_val == '-')
        name_and_val++;                               // skip second - too
      string key;
      const char* value;
      CommandLineFlag* flag = registry_->SplitArgumentLocked(name_and_val,
                                                             &key, &value);
      // By API, errors parsing flagfile lines are silently ignored.
      if (flag == NULL) {
        // "WARNING: flagname '" + key + "' not found\n"
      } else if (value == NULL) {
        // "WARNING: flagname '" + key + "' missing a value\n"
      } else {
        retval += ProcessSingleOptionLocked(flag, value, set_mode);
      }

    } else {                        // a filename!
      if (!in_filename_section) {   // start over: assume filenames don't match
        in_filename_section = true;
        flags_are_relevant = false;
      }

      // Split the line up at spaces into glob-patterns
      const char* space = line.c_str();   // just has to be non-NULL
      for (const char* word = line.c_str(); *space; word = space+1) {
        if (flags_are_relevant)     // we can stop as soon as we match
          break;
        space = strchr(word, ' ');
        if (space == NULL)
          space = word + strlen(word);
        const string glob(word, space - word);
        // We try matching both against the full argv0 and basename(argv0)
        if (fnmatch(glob.c_str(), ProgramInvocationName(), FNM_PATHNAME) == 0 ||
            fnmatch(glob.c_str(), ProgramInvocationShortName(), FNM_PATHNAME) == 0) {
          flags_are_relevant = true;
        }
      }
    }
  }
  return retval;
}


// --------------------------------------------------------------------
// GetCommandLineOption()
// GetCommandLineFlagInfo()
// GetCommandLineFlagInfoOrDie()
// SetCommandLineOption()
// SetCommandLineOptionWithMode()
//    The programmatic way to set a flag's value, using a string
//    for its name rather than the variable itself (that is,
//    SetCommandLineOption("foo", x) rather than FLAGS_foo = x).
//    There's also a bit more flexibility here due to the various
//    set-modes, but typically these are used when you only have
//    that flag's name as a string, perhaps at runtime.
//    All of these work on the default, global registry.
//       For GetCommandLineOption, return false if no such flag
//    is known, true otherwise.  We clear "value" if a suitable
//    flag is found.
// --------------------------------------------------------------------


bool GetCommandLineOption(const char* name, string* value) {
  if (NULL == name)
    return false;
  assert(value);

  FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
  registry->Lock();
  CommandLineFlag* flag = registry->FindFlagLocked(name);
  if (flag == NULL) {
    registry->Unlock();
    return false;
  } else {
    *value = flag->current_value();
    registry->Unlock();
    return true;
  }
}

bool GetCommandLineFlagInfo(const char* name, CommandLineFlagInfo* OUTPUT) {
  if (NULL == name) return false;
  FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
  registry->Lock();
  CommandLineFlag* flag = registry->FindFlagLocked(name);
  if (flag == NULL) {
    registry->Unlock();
    return false;
  } else {
    assert(OUTPUT);
    flag->FillCommandLineFlagInfo(OUTPUT);
    registry->Unlock();
    return true;
  }
}

CommandLineFlagInfo GetCommandLineFlagInfoOrDie(const char* name) {
  CommandLineFlagInfo info;
  if (!GetCommandLineFlagInfo(name, &info)) {
    fprintf(stderr, "FATAL ERROR: flag name '%s' doesn't exit", name);
    commandlineflags_exitfunc(1);    // almost certainly exit()
  }
  return info;
}

string SetCommandLineOptionWithMode(const char* name, const char* value,
                                    FlagSettingMode set_mode) {
  string result;
  FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
  registry->Lock();
  CommandLineFlag* flag = registry->FindFlagLocked(name);
  if (flag) {
    CommandLineFlagParser parser(registry);
    result = parser.ProcessSingleOptionLocked(flag, value, set_mode);
    if (!result.empty()) {   // in the error case, we've already logged
      // You could consider logging this change, if you wanted to know it:
      //fprintf(stderr, "%sFLAGS_%s\n",
      //        (set_mode == SET_FLAGS_DEFAULT ? "default value of " : ""),
      //        result);
    }
  }
  registry->Unlock();
  // The API of this function is that we return empty string on error
  return result;
}

string SetCommandLineOption(const char* name, const char* value) {
  return SetCommandLineOptionWithMode(name, value, SET_FLAGS_VALUE);
}


// --------------------------------------------------------------------
// FlagSaver
// FlagSaverImpl
//    This class stores the states of all flags at construct time,
//    and restores all flags to that state at destruct time.
//    Its major implementation challenge is that it never modifies
//    pointers in the 'main' registry, so global FLAG_* vars always
//    point to the right place.
// --------------------------------------------------------------------

class FlagSaverImpl {
 public:
  // Constructs an empty FlagSaverImpl object.
  explicit FlagSaverImpl(FlagRegistry* main_registry)
      : main_registry_(main_registry) { }
  ~FlagSaverImpl() {
    // reclaim memory from each of our CommandLineFlags
    vector<CommandLineFlag*>::const_iterator it;
    for (it = backup_registry_.begin(); it != backup_registry_.end(); ++it)
      delete *it;
  }

  // Saves the flag states from the flag registry into this object.
  // It's an error to call this more than once.
  // Must be called when the registry mutex is not held.
  void SaveFromRegistry() {
    main_registry_->Lock();
    assert(backup_registry_.empty());   // call only once!
    for (FlagRegistry::FlagConstIterator it = main_registry_->flags_.begin();
         it != main_registry_->flags_.end();
         ++it) {
      const CommandLineFlag* main = it->second;
      // Sets up all the const variables in backup correctly
      CommandLineFlag* backup = new CommandLineFlag(
          main->name(), main->help(), main->filename(),
          main->current_->New(), main->defvalue_->New());
      // Sets up all the non-const variables in backup correctly
      backup->CopyFrom(*main);
      backup_registry_.push_back(backup);   // add it to a convenient list
    }
    main_registry_->Unlock();
  }

  // Restores the saved flag states into the flag registry.  We
  // assume no flags were added or deleted from the registry since
  // the SaveFromRegistry; if they were, that's trouble!  Must be
  // called when the registry mutex is not held.
  void RestoreToRegistry() {
    main_registry_->Lock();
    vector<CommandLineFlag*>::const_iterator it;
    for (it = backup_registry_.begin(); it != backup_registry_.end(); ++it) {
      CommandLineFlag* main = main_registry_->FindFlagLocked((*it)->name());
      if (main != NULL) {       // if NULL, flag got deleted from registry(!)
        main->CopyFrom(**it);
      }
    }
    main_registry_->Unlock();
  }

 private:
  FlagRegistry* const main_registry_;
  vector<CommandLineFlag*> backup_registry_;

  FlagSaverImpl(const FlagSaverImpl&);  // no copying!
  void operator=(const FlagSaverImpl&);
};

FlagSaver::FlagSaver() : impl_(new FlagSaverImpl(FlagRegistry::GlobalRegistry())) {
  impl_->SaveFromRegistry();
}

FlagSaver::~FlagSaver() {
  impl_->RestoreToRegistry();
  delete impl_;
}


// --------------------------------------------------------------------
// CommandlineFlagsIntoString()
// ReadFlagsFromString()
// AppendFlagsIntoFile()
// ReadFromFlagsFile()
//    These are mostly-deprecated routines that stick the
//    commandline flags into a file/string and read them back
//    out again.  I can see a use for CommandlineFlagsIntoString,
//    for creating a flagfile, but the rest don't seem that useful
//    -- some, I think, are a poor-man's attempt at FlagSaver --
//    and are included only until we can delete them from callers.
//    Note they don't save --flagfile flags (though they do save
//    the result of having called the flagfile, of course).
// --------------------------------------------------------------------

static string TheseCommandlineFlagsIntoString(
    const vector<CommandLineFlagInfo>& flags) {
  vector<CommandLineFlagInfo>::const_iterator i;

  int retval_space = 0;
  for (i = flags.begin(); i != flags.end(); ++i) {
    // An (over)estimate of how much space it will take to print this flag
    retval_space += i->name.length() + i->current_value.length() + 5;
  }

  string retval;
  retval.reserve(retval_space);
  for (i = flags.begin(); i != flags.end(); ++i) {
    retval += "--";
    retval += i->name;
    retval += "=";
    retval += i->current_value;
    retval += "\n";
  }
  return retval;
}

string CommandlineFlagsIntoString() {
  vector<CommandLineFlagInfo> sorted_flags;
  GetAllFlags(&sorted_flags);
  return TheseCommandlineFlagsIntoString(sorted_flags);
}

bool ReadFlagsFromString(const string& flagfilecontents,
                         const char* prog_name,   // TODO(csilvers): nix this
                         bool errors_are_fatal) {
  FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
  FlagSaverImpl saved_states(registry);
  saved_states.SaveFromRegistry();

  CommandLineFlagParser parser(registry);
  registry->Lock();
  parser.ProcessOptionsFromStringLocked(flagfilecontents, SET_FLAGS_VALUE);
  registry->Unlock();
  // Should we handle --help and such when reading flags from a string?  Sure.
  HandleCommandLineHelpFlags();
  if (parser.ReportErrors()) {
    // Error.  Restore all global flags to their previous values.
    if (errors_are_fatal)
      commandlineflags_exitfunc(1);    // almost certainly exit()
    saved_states.RestoreToRegistry();
    return false;
  }
  return true;
}

// TODO(csilvers): nix prog_name in favor of ProgramInvocationShortName()
bool AppendFlagsIntoFile(const string& filename, const char *prog_name) {
  FILE *fp = fopen(filename.c_str(), "a");
  if (!fp) {
    return false;
  }

  if (prog_name)
    fprintf(fp, "%s\n", prog_name);

  vector<CommandLineFlagInfo> flags;
  GetAllFlags(&flags);
  // But we don't want --flagfile, which leads to weird recursion issues
  vector<CommandLineFlagInfo>::iterator i;
  for (i = flags.begin(); i != flags.end(); ++i) {
    if (strcmp(i->name.c_str(), "flagfile") == 0) {
      flags.erase(i);
      break;
    }
  }
  fprintf(fp, "%s", TheseCommandlineFlagsIntoString(flags).c_str());

  fclose(fp);
  return true;
}

bool ReadFromFlagsFile(const string& filename, const char* prog_name,
                       bool errors_are_fatal) {
  return ReadFlagsFromString(ReadFileIntoString(filename.c_str()),
                             prog_name, errors_are_fatal);
}


// --------------------------------------------------------------------
// BoolFromEnv()
// Int32FromEnv()
// Int64FromEnv()
// Uint64FromEnv()
// DoubleFromEnv()
// StringFromEnv()
//    Reads the value from the environment and returns it.
//    We use an FlagValue to make the parsing easy.
//    Example usage:
//       DEFINE_bool(myflag, BoolFromEnv("MYFLAG_DEFAULT", false), "whatever");
// --------------------------------------------------------------------

template<typename T>
T GetFromEnv(const char *varname, const char* type, T dflt) {
  const char* const valstr = getenv(varname);
  if (!valstr)
    return dflt;
  FlagValue ifv(new T, type);
  if (!ifv.ParseFrom(valstr)) {
    fprintf(stderr, "ERROR: error parsing env variable '%s' with value '%s'\n",
            varname, valstr);
    commandlineflags_exitfunc(1);   // almost certainly exit()
  }
  return OTHER_VALUE_AS(ifv, T);
}

bool BoolFromEnv(const char *v, bool dflt) {
  return GetFromEnv(v, "bool", dflt);
}
int32 Int32FromEnv(const char *v, int32 dflt) {
  return GetFromEnv(v, "int32", dflt);
}
int64 Int64FromEnv(const char *v, int64 dflt)    {
  return GetFromEnv(v, "int64", dflt);
}
uint64 Uint64FromEnv(const char *v, uint64 dflt) {
  return GetFromEnv(v, "uint64", dflt);
}
double DoubleFromEnv(const char *v, double dflt) {
  return GetFromEnv(v, "double", dflt);
}
const char *StringFromEnv(const char *varname, const char *dflt) {
  const char* const val = getenv(varname);
  return val ? val : dflt;
}


// --------------------------------------------------------------------
// ParseCommandLineFlags()
// ParseCommandLineNonHelpFlags()
// HandleCommandLineHelpFlags()
//    This is the main function called from main(), to actually
//    parse the commandline.  It modifies argc and argv as described
//    at the top of commandlineflags.h.  You can also divide this
//    function into two parts, if you want to do work between
//    the parsing of the flags and the printing of any help output.
// --------------------------------------------------------------------

static uint32 ParseCommandLineFlagsInternal(int* argc, char*** argv,
                                            bool remove_flags, bool do_report) {
  SetArgv(*argc, const_cast<const char**>(*argv));    // save it for later

  FlagRegistry* const registry = FlagRegistry::GlobalRegistry();
  CommandLineFlagParser parser(registry);

  // When we parse the commandline flags, we'll handle --flagfile,
  // --tryfromenv, etc. as we see them (since flag-evaluation order
  // may be important).  But sometimes apps set FLAGS_tryfromenv/etc.
  // manually before calling ParseCommandLineFlags.  We want to evaluate
  // those too, as if they were the first flags on the commandline.
  registry->Lock();
  parser.ProcessFlagfileLocked(FLAGS_flagfile, SET_FLAGS_VALUE);
  // Last arg here indicates whether flag-not-found is a fatal error or not
  parser.ProcessFromenvLocked(FLAGS_fromenv, SET_FLAGS_VALUE, true);
  parser.ProcessFromenvLocked(FLAGS_tryfromenv, SET_FLAGS_VALUE, false);
  registry->Unlock();

  // Now get the flags specified on the commandline
  const int r = parser.ParseNewCommandLineFlags(argc, argv, remove_flags);

  if (do_report)
    HandleCommandLineHelpFlags();   // may cause us to exit on --help, etc.
  if (parser.ReportErrors())        // may cause us to exit on illegal flags
    commandlineflags_exitfunc(1);   // almost certainly exit()
  return r;
}

uint32 ParseCommandLineFlags(int* argc, char*** argv, bool remove_flags) {
  return ParseCommandLineFlagsInternal(argc, argv, remove_flags, true);
}

uint32 ParseCommandLineNonHelpFlags(int* argc, char*** argv,
                                    bool remove_flags) {
  return ParseCommandLineFlagsInternal(argc, argv, remove_flags, false);
}

// --------------------------------------------------------------------
// AllowCommandLineReparsing()
// ReparseCommandLineNonHelpFlags()
//    This is most useful for shared libraries.  The idea is if
//    a flag is defined in a shared library that is dlopen'ed
//    sometime after main(), you can ParseCommandLineFlags before
//    the dlopen, then ReparseCommandLineNonHelpFlags() after the
//    dlopen, to get the new flags.  But you have to explicitly
//    Allow() it; otherwise, you get the normal default behavior
//    of unrecognized flags calling a fatal error.
//    TODO(csilvers): this isn't used.  Just delete it?
// --------------------------------------------------------------------

void AllowCommandLineReparsing() {
  allow_command_line_reparsing = true;
}

uint32 ReparseCommandLineNonHelpFlags() {
  // We make a copy of argc and argv to pass in
  const vector<string>& argvs = GetArgvs();
  int tmp_argc = argvs.size();
  char** tmp_argv = new char* [tmp_argc + 1];
  for (int i = 0; i < tmp_argc; ++i)
    tmp_argv[i] = strdup(argvs[i].c_str());   // TODO(csilvers): don't dup

  const int retval = ParseCommandLineNonHelpFlags(&tmp_argc, &tmp_argv, false);

  for (int i = 0; i < tmp_argc; ++i)
    free(tmp_argv[i]);
  delete[] tmp_argv;

  return retval;
}

_END_GOOGLE_NAMESPACE_