gopkg.in/alecthomas/gometalinter.v3@v3.0.0/_linters/src/golang.org/x/tools/go/buildutil/fakecontext.go (about)

     1  package buildutil
     2  
     3  import (
     4  	"fmt"
     5  	"go/build"
     6  	"io"
     7  	"io/ioutil"
     8  	"os"
     9  	"path"
    10  	"path/filepath"
    11  	"sort"
    12  	"strings"
    13  	"time"
    14  )
    15  
    16  // FakeContext returns a build.Context for the fake file tree specified
    17  // by pkgs, which maps package import paths to a mapping from file base
    18  // names to contents.
    19  //
    20  // The fake Context has a GOROOT of "/go" and no GOPATH, and overrides
    21  // the necessary file access methods to read from memory instead of the
    22  // real file system.
    23  //
    24  // Unlike a real file tree, the fake one has only two levels---packages
    25  // and files---so ReadDir("/go/src/") returns all packages under
    26  // /go/src/ including, for instance, "math" and "math/big".
    27  // ReadDir("/go/src/math/big") would return all the files in the
    28  // "math/big" package.
    29  //
    30  func FakeContext(pkgs map[string]map[string]string) *build.Context {
    31  	clean := func(filename string) string {
    32  		f := path.Clean(filepath.ToSlash(filename))
    33  		// Removing "/go/src" while respecting segment
    34  		// boundaries has this unfortunate corner case:
    35  		if f == "/go/src" {
    36  			return ""
    37  		}
    38  		return strings.TrimPrefix(f, "/go/src/")
    39  	}
    40  
    41  	ctxt := build.Default // copy
    42  	ctxt.GOROOT = "/go"
    43  	ctxt.GOPATH = ""
    44  	ctxt.IsDir = func(dir string) bool {
    45  		dir = clean(dir)
    46  		if dir == "" {
    47  			return true // needed by (*build.Context).SrcDirs
    48  		}
    49  		return pkgs[dir] != nil
    50  	}
    51  	ctxt.ReadDir = func(dir string) ([]os.FileInfo, error) {
    52  		dir = clean(dir)
    53  		var fis []os.FileInfo
    54  		if dir == "" {
    55  			// enumerate packages
    56  			for importPath := range pkgs {
    57  				fis = append(fis, fakeDirInfo(importPath))
    58  			}
    59  		} else {
    60  			// enumerate files of package
    61  			for basename := range pkgs[dir] {
    62  				fis = append(fis, fakeFileInfo(basename))
    63  			}
    64  		}
    65  		sort.Sort(byName(fis))
    66  		return fis, nil
    67  	}
    68  	ctxt.OpenFile = func(filename string) (io.ReadCloser, error) {
    69  		filename = clean(filename)
    70  		dir, base := path.Split(filename)
    71  		content, ok := pkgs[path.Clean(dir)][base]
    72  		if !ok {
    73  			return nil, fmt.Errorf("file not found: %s", filename)
    74  		}
    75  		return ioutil.NopCloser(strings.NewReader(content)), nil
    76  	}
    77  	ctxt.IsAbsPath = func(path string) bool {
    78  		path = filepath.ToSlash(path)
    79  		// Don't rely on the default (filepath.Path) since on
    80  		// Windows, it reports virtual paths as non-absolute.
    81  		return strings.HasPrefix(path, "/")
    82  	}
    83  	return &ctxt
    84  }
    85  
    86  type byName []os.FileInfo
    87  
    88  func (s byName) Len() int           { return len(s) }
    89  func (s byName) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
    90  func (s byName) Less(i, j int) bool { return s[i].Name() < s[j].Name() }
    91  
    92  type fakeFileInfo string
    93  
    94  func (fi fakeFileInfo) Name() string    { return string(fi) }
    95  func (fakeFileInfo) Sys() interface{}   { return nil }
    96  func (fakeFileInfo) ModTime() time.Time { return time.Time{} }
    97  func (fakeFileInfo) IsDir() bool        { return false }
    98  func (fakeFileInfo) Size() int64        { return 0 }
    99  func (fakeFileInfo) Mode() os.FileMode  { return 0644 }
   100  
   101  type fakeDirInfo string
   102  
   103  func (fd fakeDirInfo) Name() string    { return string(fd) }
   104  func (fakeDirInfo) Sys() interface{}   { return nil }
   105  func (fakeDirInfo) ModTime() time.Time { return time.Time{} }
   106  func (fakeDirInfo) IsDir() bool        { return true }
   107  func (fakeDirInfo) Size() int64        { return 0 }
   108  func (fakeDirInfo) Mode() os.FileMode  { return 0755 }