Generate "code generated" comment. Closes #47

gojson/gojson.go

@@ -63,6 +63,7 @@ var (
 	tags        = flag.String("tags", "fmt", "comma seperated list of the tags to put on the struct, default is the same as fmt")
 	forceFloats = flag.Bool("forcefloats", false, "[experimental] force float64 type for integral values")
 	subStruct   = flag.Bool("subStruct", false, "create types for sub-structs (default is false)")
+	comment     = flag.Bool("comment", true, "generate comment indicating generated code")
 )
 
 func main() {
@@ -108,7 +109,7 @@ func main() {
 		parser = ParseYaml
 	}
 
-	if output, err := Generate(input, parser, *name, *pkg, tagList, *subStruct, convertFloats); err != nil {
+	if output, err := Generate(input, parser, *name, *pkg, tagList, *subStruct, convertFloats, *comment); err != nil {
 		fmt.Fprintln(os.Stderr, "error parsing", err)
 		os.Exit(1)
 	} else {

json-to-array_test.go

@@ -26,7 +26,7 @@ func TestExampleArray(t *testing.T) {
 		t.Fatalf("error reading example_array.go: %s", err)
 	}
 
-	actual, err := Generate(i, ParseJson, "Users", "gojson", []string{"json"}, false, true)
+	actual, err := Generate(i, ParseJson, "Users", "gojson", []string{"json"}, false, true, false)
 	if err != nil {
 		t.Fatal(err)
 	}

json-to-struct.go

@@ -114,6 +114,8 @@ import (
 
 var ForceFloats bool
 
+const codeGeneratedComment = "// Code generated by gojson. DO NOT EDIT.\n\n"
+
 // commonInitialisms is a set of common initialisms.
 // Only add entries that are highly unlikely to be non-initialisms.
 // For instance, "ID" is fine (Freudian code is rare), but "AND" is not.
@@ -198,7 +200,7 @@ func readFile(input io.Reader) ([]byte, error) {
 }
 
 // Generate a struct definition given a JSON string representation of an object and a name structName.
-func Generate(input io.Reader, parser Parser, structName, pkgName string, tags []string, subStruct bool, convertFloats bool) ([]byte, error) {
+func Generate(input io.Reader, parser Parser, structName, pkgName string, tags []string, subStruct, convertFloats, comment bool) ([]byte, error) {
 	var subStructMap map[string]string = nil
 	if subStruct {
 		subStructMap = make(map[string]string)
@@ -246,6 +248,10 @@ func Generate(input io.Reader, parser Parser, structName, pkgName string, tags [
 		src = fmt.Sprintf("%v\n\ntype %v %v", src, subStructMap[k], k)
 	}
 
+	if comment {
+		src = codeGeneratedComment + src
+	}
+
 	formatted, err := format.Source([]byte(src))
 	if err != nil {
 		err = fmt.Errorf("error formatting: %s, was formatting\n%s", err, src)

json-to-struct_test.go

@@ -1,6 +1,7 @@
 package gojson
 
 import (
+	"bytes"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -12,31 +13,31 @@ import (
 // It does not (yet) test for correctness of the end result
 func TestSimpleJson(t *testing.T) {
 	i := strings.NewReader(`{"foo" : "bar"}`)
-	if _, err := Generate(i, ParseJson, "TestStruct", "gojson", []string{"json"}, false, true); err != nil {
+	if _, err := Generate(i, ParseJson, "TestStruct", "gojson", []string{"json"}, false, true, false); err != nil {
 		t.Error("Generate() error:", err)
 	}
 }
 
 // TestNullableJson tests that a null JSON value is handled properly
 func TestNullableJson(t *testing.T) {
 	i := strings.NewReader(`{"foo" : "bar", "baz" : null}`)
-	if _, err := Generate(i, ParseJson, "TestStruct", "gojson", []string{"json"}, false, true); err != nil {
+	if _, err := Generate(i, ParseJson, "TestStruct", "gojson", []string{"json"}, false, true, false); err != nil {
 		t.Error("Generate() error:", err)
 	}
 }
 
 // TestSimpleArray tests that an array without conflicting types is handled correctly
 func TestSimpleArray(t *testing.T) {
 	i := strings.NewReader(`{"foo" : [{"bar": 24}, {"bar" : 42}]}`)
-	if _, err := Generate(i, ParseJson, "TestStruct", "gojson", []string{"json"}, false, true); err != nil {
+	if _, err := Generate(i, ParseJson, "TestStruct", "gojson", []string{"json"}, false, true, false); err != nil {
 		t.Error("Generate() error:", err)
 	}
 }
 
 // TestInvalidFieldChars tests that a document with invalid field chars is handled correctly
 func TestInvalidFieldChars(t *testing.T) {
 	i := strings.NewReader(`{"f.o-o" : 42}`)
-	if _, err := Generate(i, ParseJson, "TestStruct", "gojson", []string{"json"}, false, true); err != nil {
+	if _, err := Generate(i, ParseJson, "TestStruct", "gojson", []string{"json"}, false, true, false); err != nil {
 		t.Error("Generate() error:", err)
 	}
 }
@@ -80,7 +81,7 @@ func TestInferFloatInt(t *testing.T) {
 		t.Fatalf("error reading expected_floats.go.out: %s", err)
 	}
 
-	actual, err := Generate(f, ParseJson, "Stats", "gojson", []string{"json"}, false, true)
+	actual, err := Generate(f, ParseJson, "Stats", "gojson", []string{"json"}, false, true, false)
 	if err != nil {
 		t.Error(err)
 	}
@@ -104,7 +105,7 @@ func TestYamlNumbers(t *testing.T) {
 		t.Fatalf("error reading expected_numbers.go.out: %s", err)
 	}
 
-	actual, err := Generate(f, ParseYaml, "Stats", "gojson", []string{"yaml"}, false, false)
+	actual, err := Generate(f, ParseYaml, "Stats", "gojson", []string{"yaml"}, false, false, false)
 	if err != nil {
 		t.Error(err)
 	}
@@ -126,7 +127,7 @@ func TestExample(t *testing.T) {
 		t.Error("error reading expected_output_test.go", err)
 	}
 
-	actual, err := Generate(i, ParseJson, "User", "gojson", []string{"json"}, false, true)
+	actual, err := Generate(i, ParseJson, "User", "gojson", []string{"json"}, false, true, false)
 	if err != nil {
 		t.Error(err)
 	}
@@ -159,3 +160,12 @@ func TestFmtFieldName(t *testing.T) {
 		}
 	}
 }
+
+func TestCodeGeneratedComment(t *testing.T) {
+	i := strings.NewReader(`{"foo" : "bar"}`)
+	if generated, err := Generate(i, ParseJson, "TestStruct", "gojson", []string{"json"}, false, true, true); err != nil {
+		t.Error("Generate() error:", err)
+	} else if !bytes.HasPrefix(generated, []byte(codeGeneratedComment)) {
+		t.Errorf("error generated code should contain comment indicationg code was generated")
+	}
+}