Update to last common bleve (#3986)

vendor/github.com/tinylib/msgp/msgp/file.go

@@ -0,0 +1,92 @@
+// +build linux darwin dragonfly freebsd netbsd openbsd
+// +build !appengine
+
+package msgp
+
+import (
+	"os"
+	"syscall"
+)
+
+// ReadFile reads a file into 'dst' using
+// a read-only memory mapping. Consequently,
+// the file must be mmap-able, and the
+// Unmarshaler should never write to
+// the source memory. (Methods generated
+// by the msgp tool obey that constraint, but
+// user-defined implementations may not.)
+//
+// Reading and writing through file mappings
+// is only efficient for large files; small
+// files are best read and written using
+// the ordinary streaming interfaces.
+//
+func ReadFile(dst Unmarshaler, file *os.File) error {
+	stat, err := file.Stat()
+	if err != nil {
+		return err
+	}
+	data, err := syscall.Mmap(int(file.Fd()), 0, int(stat.Size()), syscall.PROT_READ, syscall.MAP_SHARED)
+	if err != nil {
+		return err
+	}
+	adviseRead(data)
+	_, err = dst.UnmarshalMsg(data)
+	uerr := syscall.Munmap(data)
+	if err == nil {
+		err = uerr
+	}
+	return err
+}
+
+// MarshalSizer is the combination
+// of the Marshaler and Sizer
+// interfaces.
+type MarshalSizer interface {
+	Marshaler
+	Sizer
+}
+
+// WriteFile writes a file from 'src' using
+// memory mapping. It overwrites the entire
+// contents of the previous file.
+// The mapping size is calculated
+// using the `Msgsize()` method
+// of 'src', so it must produce a result
+// equal to or greater than the actual encoded
+// size of the object. Otherwise,
+// a fault (SIGBUS) will occur.
+//
+// Reading and writing through file mappings
+// is only efficient for large files; small
+// files are best read and written using
+// the ordinary streaming interfaces.
+//
+// NOTE: The performance of this call
+// is highly OS- and filesystem-dependent.
+// Users should take care to test that this
+// performs as expected in a production environment.
+// (Linux users should run a kernel and filesystem
+// that support fallocate(2) for the best results.)
+func WriteFile(src MarshalSizer, file *os.File) error {
+	sz := src.Msgsize()
+	err := fallocate(file, int64(sz))
+	if err != nil {
+		return err
+	}
+	data, err := syscall.Mmap(int(file.Fd()), 0, sz, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
+	if err != nil {
+		return err
+	}
+	adviseWrite(data)
+	chunk := data[:0]
+	chunk, err = src.MarshalMsg(chunk)
+	if err != nil {
+		return err
+	}
+	uerr := syscall.Munmap(data)
+	if uerr != nil {
+		return uerr
+	}
+	return file.Truncate(int64(len(chunk)))
+}