github.com/nalekseevs/itns-golangci-lint@v1.0.2/internal/cache/default.go (about)

     1  // Copyright 2017 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package cache
     6  
     7  import (
     8  	"fmt"
     9  	"log"
    10  	"os"
    11  	"path/filepath"
    12  	"sync"
    13  )
    14  
    15  const envGolangciLintCache = "GOLANGCI_LINT_CACHE"
    16  
    17  // Default returns the default cache to use.
    18  func Default() (*Cache, error) {
    19  	defaultOnce.Do(initDefaultCache)
    20  	return defaultCache, defaultDirErr
    21  }
    22  
    23  var (
    24  	defaultOnce  sync.Once
    25  	defaultCache *Cache
    26  )
    27  
    28  // cacheREADME is a message stored in a README in the cache directory.
    29  // Because the cache lives outside the normal Go trees, we leave the
    30  // README as a courtesy to explain where it came from.
    31  const cacheREADME = `This directory holds cached build artifacts from golangci-lint.
    32  `
    33  
    34  // initDefaultCache does the work of finding the default cache
    35  // the first time Default is called.
    36  func initDefaultCache() {
    37  	dir := DefaultDir()
    38  	if err := os.MkdirAll(dir, 0744); err != nil {
    39  		log.Fatalf("failed to initialize build cache at %s: %s\n", dir, err)
    40  	}
    41  	if _, err := os.Stat(filepath.Join(dir, "README")); err != nil {
    42  		// Best effort.
    43  		if wErr := os.WriteFile(filepath.Join(dir, "README"), []byte(cacheREADME), 0666); wErr != nil {
    44  			log.Fatalf("Failed to write README file to cache dir %s: %s", dir, err)
    45  		}
    46  	}
    47  
    48  	c, err := Open(dir)
    49  	if err != nil {
    50  		log.Fatalf("failed to initialize build cache at %s: %s\n", dir, err)
    51  	}
    52  	defaultCache = c
    53  }
    54  
    55  var (
    56  	defaultDirOnce sync.Once
    57  	defaultDir     string
    58  	defaultDirErr  error
    59  )
    60  
    61  // DefaultDir returns the effective GOLANGCI_LINT_CACHE setting.
    62  func DefaultDir() string {
    63  	// Save the result of the first call to DefaultDir for later use in
    64  	// initDefaultCache. cmd/go/main.go explicitly sets GOCACHE so that
    65  	// subprocesses will inherit it, but that means initDefaultCache can't
    66  	// otherwise distinguish between an explicit "off" and a UserCacheDir error.
    67  
    68  	defaultDirOnce.Do(func() {
    69  		defaultDir = os.Getenv(envGolangciLintCache)
    70  		if filepath.IsAbs(defaultDir) {
    71  			return
    72  		}
    73  		if defaultDir != "" {
    74  			defaultDirErr = fmt.Errorf("%s is not an absolute path", envGolangciLintCache)
    75  			return
    76  		}
    77  
    78  		// Compute default location.
    79  		dir, err := os.UserCacheDir()
    80  		if err != nil {
    81  			defaultDirErr = fmt.Errorf("%s is not defined and %w", envGolangciLintCache, err)
    82  			return
    83  		}
    84  		defaultDir = filepath.Join(dir, "golangci-lint")
    85  	})
    86  
    87  	return defaultDir
    88  }