func checkZip()

in zip/zip.go [386:474]
83 lines of code
24 McCabe index (conditional complexity)

func checkZip(m module.Version, f *os.File) (*zip.Reader, CheckedFiles, error) {
	// Make sure the module path and version are valid.
	if vers := module.CanonicalVersion(m.Version); vers != m.Version {
		return nil, CheckedFiles{}, fmt.Errorf("version %q is not canonical (should be %q)", m.Version, vers)
	}
	if err := module.Check(m.Path, m.Version); err != nil {
		return nil, CheckedFiles{}, err
	}

	// Check the total file size.
	info, err := f.Stat()
	if err != nil {
		return nil, CheckedFiles{}, err
	}
	zipSize := info.Size()
	if zipSize > MaxZipFile {
		cf := CheckedFiles{SizeError: fmt.Errorf("module zip file is too large (%d bytes; limit is %d bytes)", zipSize, MaxZipFile)}
		return nil, cf, cf.Err()
	}

	// Check for valid file names, collisions.
	var cf CheckedFiles
	addError := func(zf *zip.File, err error) {
		cf.Invalid = append(cf.Invalid, FileError{Path: zf.Name, Err: err})
	}
	z, err := zip.NewReader(f, zipSize)
	if err != nil {
		return nil, CheckedFiles{}, err
	}
	prefix := fmt.Sprintf("%s@%s/", m.Path, m.Version)
	collisions := make(collisionChecker)
	var size int64
	for _, zf := range z.File {
		if !strings.HasPrefix(zf.Name, prefix) {
			addError(zf, fmt.Errorf("path does not have prefix %q", prefix))
			continue
		}
		name := zf.Name[len(prefix):]
		if name == "" {
			continue
		}
		isDir := strings.HasSuffix(name, "/")
		if isDir {
			name = name[:len(name)-1]
		}
		if path.Clean(name) != name {
			addError(zf, errPathNotClean)
			continue
		}
		if err := module.CheckFilePath(name); err != nil {
			addError(zf, err)
			continue
		}
		if err := collisions.check(name, isDir); err != nil {
			addError(zf, err)
			continue
		}
		if isDir {
			continue
		}
		if base := path.Base(name); strings.EqualFold(base, "go.mod") {
			if base != name {
				addError(zf, fmt.Errorf("go.mod file not in module root directory"))
				continue
			}
			if name != "go.mod" {
				addError(zf, errGoModCase)
				continue
			}
		}
		sz := int64(zf.UncompressedSize64)
		if sz >= 0 && MaxZipFile-size >= sz {
			size += sz
		} else if cf.SizeError == nil {
			cf.SizeError = fmt.Errorf("total uncompressed size of module contents too large (max size is %d bytes)", MaxZipFile)
		}
		if name == "go.mod" && sz > MaxGoMod {
			addError(zf, fmt.Errorf("go.mod file too large (max size is %d bytes)", MaxGoMod))
			continue
		}
		if name == "LICENSE" && sz > MaxLICENSE {
			addError(zf, fmt.Errorf("LICENSE file too large (max size is %d bytes)", MaxLICENSE))
			continue
		}
		cf.Valid = append(cf.Valid, zf.Name)
	}

	return z, cf, cf.Err()
}