go/src/cmd/go/internal/modfetch/sumdb.go

// useSumDB reports whether to use the Go checksum database for the given module.
func useSumDB(mod module.Version) bool { … }

// lookupSumDB returns the Go checksum database's go.sum lines for the given module,
// along with the name of the database.
func lookupSumDB(mod module.Version) (dbname string, lines []string, err error) { … }

var dbOnce …

var dbName …

var db …

var dbErr …

func dbDial() (dbName string, db *sumdb.Client, err error) { … }

type dbClient …

func (c *dbClient) ReadRemote(path string) ([]byte, error) { … }

// initBase determines the base URL for connecting to the database.
// Determining the URL requires sending network traffic to proxies,
// so this work is delayed until we need to download something from
// the database. If everything we need is in the local cache and
// c.ReadRemote is never called, we will never do this work.
func (c *dbClient) initBase() { … }

// ReadConfig reads the key from c.key
// and otherwise reads the config (a latest tree head) from GOPATH/pkg/sumdb/<file>.
func (c *dbClient) ReadConfig(file string) (data []byte, err error) { … }

// WriteConfig rewrites the latest tree head.
func (*dbClient) WriteConfig(file string, old, new []byte) error { … }

// ReadCache reads cached lookups or tiles from
// GOPATH/pkg/mod/cache/download/sumdb,
// which will be deleted by "go clean -modcache".
func (*dbClient) ReadCache(file string) ([]byte, error) { … }

// WriteCache updates cached lookups or tiles.
func (*dbClient) WriteCache(file string, data []byte) { … }

func (*dbClient) Log(msg string) { … }

func (*dbClient) SecurityError(msg string) { … }