Merge pull request #127 from kvii/pr_nil_bytes

Add check for passing empty bytes

Author: gen2brain

fitz.go

@@ -12,6 +12,7 @@ var (
 	ErrNoSuchFile      = errors.New("fitz: no such file")
 	ErrCreateContext   = errors.New("fitz: cannot create context")
 	ErrOpenDocument    = errors.New("fitz: cannot open document")
+	ErrEmptyBytes      = errors.New("fitz: cannot send empty bytes")
 	ErrOpenMemory      = errors.New("fitz: cannot open memory")
 	ErrLoadPage        = errors.New("fitz: cannot load page")
 	ErrRunPageContents = errors.New("fitz: cannot run page contents")

fitz_cgo.go

@@ -125,6 +125,9 @@ func New(filename string) (f *Document, err error) {
 
 // NewFromMemory returns new fitz document from byte slice.
 func NewFromMemory(b []byte) (f *Document, err error) {
+	if len(b) == 0 {
+		return nil, ErrEmptyBytes
+	}
 	f = &Document{}
 
 	f.ctx = (*C.struct_fz_context)(unsafe.Pointer(C.fz_new_context_imp(nil, nil, C.store(MaxStore), C.fz_version)))

fitz_nocgo.go

@@ -64,6 +64,9 @@ func New(filename string) (f *Document, err error) {
 
 // NewFromMemory returns new fitz document from byte slice.
 func NewFromMemory(b []byte) (f *Document, err error) {
+	if len(b) = 0 {
+		return nil, ErrEmptyBytes
+	}
 	f = &Document{}
 
 	f.ctx = fzNewContextImp(nil, nil, uint64(MaxStore), FzVersion)

fitz_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"image"
 	"image/jpeg"
+	"io"
 	"os"
 	"path/filepath"
 	"testing"
@@ -293,3 +294,26 @@ func TestBound(t *testing.T) {
 		t.Error(fmt.Errorf("ErrPageMissing not returned got %v", err))
 	}
 }
+
+func TestEmptyBytes(t *testing.T) {
+	var err error
+	// empty reader
+	_, err = fitz.NewFromReader(emptyReader{})
+	if !errors.Is(err, fitz.ErrEmptyBytes) {
+		t.Errorf("Expected ErrEmptyBytes, got %v", err)
+	}
+	// nil slice
+	_, err = fitz.NewFromMemory(nil)
+	if !errors.Is(err, fitz.ErrEmptyBytes) {
+		t.Errorf("Expected ErrEmptyBytes, got %v", err)
+	}
+	// empty slice
+	_, err = fitz.NewFromMemory(make([]byte, 0))
+	if !errors.Is(err, fitz.ErrEmptyBytes) {
+		t.Errorf("Expected ErrEmptyBytes, got %v", err)
+	}
+}
+
+type emptyReader struct{}
+
+func (emptyReader) Read([]byte) (int, error) { return 0, io.EOF }