Refactor module-detection to use go/build instead of static file

v2/common/testing_common.go

@@ -1,9 +1,10 @@
 package exifcommon
 
 import (
-	"os"
 	"path"
 
+	"go/build"
+
 	"encoding/binary"
 	"io/ioutil"
 
@@ -23,63 +24,32 @@ var (
 	TestDefaultByteOrder = binary.BigEndian
 )
 
+// GetModuleRootPath returns our source-path when running from source during
+// tests.
 func GetModuleRootPath() string {
-	if moduleRootPath != "" {
-		return moduleRootPath
-	}
+	p, err := build.Default.Import(
+		"github.com/dsoprea/go-exif/v2",
+		build.Default.GOPATH,
+		build.FindOnly)
 
-	moduleRootPath := os.Getenv("EXIF_MODULE_ROOT_PATH")
-	if moduleRootPath != "" {
-		return moduleRootPath
-	}
-
-	currentWd, err := os.Getwd()
 	log.PanicIf(err)
 
-	currentPath := currentWd
-	visited := make([]string, 0)
-
-	for {
-		tryStampFilepath := path.Join(currentPath, ".MODULE_ROOT")
-
-		_, err := os.Stat(tryStampFilepath)
-		if err != nil && os.IsNotExist(err) != true {
-			log.Panic(err)
-		} else if err == nil {
-			break
-		}
-
-		visited = append(visited, tryStampFilepath)
-
-		currentPath = path.Dir(currentPath)
-		if currentPath == "/" {
-			log.Panicf("could not find module-root: %v", visited)
-		}
-	}
-
-	return currentPath
+	packagePath := p.Dir
+	return packagePath
 }
 
 func getTestAssetsPath() string {
-	if assetsPath == "" {
-		moduleRootPath := GetModuleRootPath()
-		assetsPath = path.Join(moduleRootPath, "assets")
-	}
+	moduleRootPath := GetModuleRootPath()
+	assetsPath := path.Join(moduleRootPath, "assets")
 
 	return assetsPath
 }
 
 func getTestImageFilepath() string {
-	if testImageFilepath == "" {
-		assetsPath := getTestAssetsPath()
-		testImageFilepath = path.Join(assetsPath, "NDM_8901.jpg")
-	}
-
-	return testImageFilepath
+	return path.Join(assetsPath, "NDM_8901.jpg")
 }
 
 func getTestExifData() []byte {
-	assetsPath := getTestAssetsPath()
 	filepath := path.Join(assetsPath, "NDM_8901.jpg.exif")
 
 	var err error
@@ -89,3 +59,7 @@ func getTestExifData() []byte {
 
 	return testExifData
 }
+
+func init() {
+	assetsPath = getTestAssetsPath()
+}

v2/exif.go

@@ -173,7 +173,7 @@ func ParseExifHeader(data []byte) (eh ExifHeader, err error) {
 	//      CIPA DC-008-2016; JEITA CP-3451D
 	//      -> http://www.cipa.jp/std/documents/e/DC-008-Translation-2016-E.pdf
 
-	if len(data) < 8 {
+	if len(data) < ExifSignatureLength {
 		exifLogger.Warningf(nil, "Not enough data for EXIF header: (%d)", len(data))
 		return eh, ErrNoExif
 	}

v2/testing_common.go

@@ -13,10 +13,7 @@ import (
 )
 
 var (
-	assetsPath           = ""
-	testImageFilepath    = ""
-	testGpsImageFilepath = ""
-
+	assetsPath   = ""
 	testExifData = make([]byte, 0)
 )
 
@@ -160,25 +157,18 @@ func validateExifSimpleTestIb(exifData []byte, t *testing.T) {
 }
 
 func getTestAssetsPath() string {
-	if assetsPath == "" {
-		moduleRootPath := exifcommon.GetModuleRootPath()
-		assetsPath = path.Join(moduleRootPath, "assets")
-	}
+	moduleRootPath := exifcommon.GetModuleRootPath()
+	assetsPath := path.Join(moduleRootPath, "assets")
 
 	return assetsPath
 }
 
 func getTestImageFilepath() string {
-	if testImageFilepath == "" {
-		assetsPath := getTestAssetsPath()
-		testImageFilepath = path.Join(assetsPath, "NDM_8901.jpg")
-	}
-
+	testImageFilepath := path.Join(assetsPath, "NDM_8901.jpg")
 	return testImageFilepath
 }
 
 func getTestExifData() []byte {
-	assetsPath := getTestAssetsPath()
 	filepath := path.Join(assetsPath, "NDM_8901.jpg.exif")
 
 	var err error
@@ -190,10 +180,10 @@ func getTestExifData() []byte {
 }
 
 func getTestGpsImageFilepath() string {
-	if testGpsImageFilepath == "" {
-		assetsPath := getTestAssetsPath()
-		testGpsImageFilepath = path.Join(assetsPath, "gps.jpg")
-	}
-
+	testGpsImageFilepath := path.Join(assetsPath, "gps.jpg")
 	return testGpsImageFilepath
 }
+
+func init() {
+	assetsPath = getTestAssetsPath()
+}