github.com/amazechain/amc@v0.1.3/common/paths/paths.go (about)

     1  // Copyright 2023 The AmazeChain Authors
     2  // This file is part of the AmazeChain library.
     3  //
     4  // The AmazeChain library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The AmazeChain library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the AmazeChain library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package paths
    18  
    19  import (
    20  	"os"
    21  	"os/user"
    22  	"path/filepath"
    23  	"runtime"
    24  	"strings"
    25  )
    26  
    27  const dirname = "Amc"
    28  
    29  // DefaultDataDir is the default data directory to use for the databases and other
    30  // persistence requirements.
    31  func DefaultDataDir() string {
    32  	// Try to place the data folder in the user's home dir
    33  	home := homeDir()
    34  	if home != "" {
    35  		switch runtime.GOOS {
    36  		case "darwin":
    37  			return filepath.Join(home, "Library", dirname)
    38  		case "windows":
    39  			// We used to put everything in %HOME%\AppData\Roaming, but this caused
    40  			// problems with non-typical setups. If this fallback location exists and
    41  			// is non-empty, use it, otherwise DTRT and check %LOCALAPPDATA%.
    42  			fallback := filepath.Join(home, "AppData", "Roaming", dirname)
    43  			appdata := windowsAppData()
    44  			if appdata == "" || isNonEmptyDir(fallback) {
    45  				return fallback
    46  			}
    47  			return filepath.Join(appdata, dirname)
    48  		default:
    49  			if xdgDataDir := os.Getenv("XDG_DATA_HOME"); xdgDataDir != "" {
    50  				return filepath.Join(xdgDataDir, strings.ToLower(dirname))
    51  			}
    52  			return filepath.Join(home, ".local/share", strings.ToLower(dirname))
    53  		}
    54  	}
    55  	// As we cannot guess a stable location, return empty and handle later
    56  	return ""
    57  }
    58  
    59  func windowsAppData() string {
    60  	v := os.Getenv("LOCALAPPDATA")
    61  	if v == "" {
    62  		// Windows XP and below don't have LocalAppData. Crash here because
    63  		// we don't support Windows XP and undefining the variable will cause
    64  		// other issues.
    65  		panic("environment variable LocalAppData is undefined")
    66  	}
    67  	return v
    68  }
    69  
    70  func isNonEmptyDir(dir string) bool {
    71  	f, err := os.Open(dir)
    72  	if err != nil {
    73  		return false
    74  	}
    75  	names, _ := f.Readdir(1)
    76  	f.Close()
    77  	return len(names) > 0
    78  }
    79  
    80  func homeDir() string {
    81  	if home := os.Getenv("HOME"); home != "" {
    82  		return home
    83  	}
    84  	if usr, err := user.Current(); err == nil {
    85  		return usr.HomeDir
    86  	}
    87  	return ""
    88  }