feat: Reader support open db from embed.fs

reader.go

@@ -3,6 +3,7 @@ package maxminddb
 
 import (
 	"bytes"
+	"embed"
 	"errors"
 	"fmt"
 	"io"
@@ -48,6 +49,23 @@ type Metadata struct {
 	RecordSize               uint              `maxminddb:"record_size"`
 }
 
+func OpenWithEmbedFS(f embed.FS, path string) (*Reader, error) {
+	data, err := f.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	reader, err := FromBytes(data)
+	if err != nil {
+		_ = munmap(data)
+		return nil, err
+	}
+
+	reader.hasMappedFile = true
+	runtime.SetFinalizer(reader, (*Reader).Close)
+	return reader, nil
+}
+
 // Open takes a string path to a MaxMind DB file and returns a Reader
 // structure or an error. The database file is opened using a memory map
 // on supported platforms. On platforms without memory map support, such

reader_test.go

@@ -1,6 +1,7 @@
 package maxminddb
 
 import (
+	"embed"
 	"errors"
 	"fmt"
 	"math/big"
@@ -16,6 +17,9 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+//go:embed test-data/test-data/*
+var f embed.FS
+
 func TestReader(t *testing.T) {
 	for _, recordSize := range []uint{24, 28, 32} {
 		for _, ipVersion := range []uint{4, 6} {
@@ -24,7 +28,10 @@ func TestReader(t *testing.T) {
 				ipVersion,
 				recordSize,
 			)
+			// log.Printf("Checking %s", fileName)
+
 			t.Run(fileName, func(t *testing.T) {
+				// reader, err := Open(testFile(fileName))
 				reader, err := Open(testFile(fileName))
 				require.NoError(t, err, "unexpected error while opening database: %v", err)
 				checkMetadata(t, reader, ipVersion, recordSize)
@@ -35,6 +42,18 @@ func TestReader(t *testing.T) {
 					checkIpv6(t, reader)
 				}
 			})
+
+			t.Run(fileName, func(t *testing.T) {
+				reader, err := OpenWithEmbedFS(f, testFile(fileName))
+				require.NoError(t, err, "unexpected error while opening database: %v", err)
+				checkMetadata(t, reader, ipVersion, recordSize)
+
+				if ipVersion == 4 {
+					checkIpv4(t, reader)
+				} else {
+					checkIpv6(t, reader)
+				}
+			})
 		}
 	}
 }