Fixed ParseBytes and ParseFile by adding agclearerrors in C

cgraph/cgraph.go

@@ -101,6 +101,7 @@ func toEdge(e *ccall.Agedge) *Edge {
 }
 
 func ParseBytes(bytes []byte) (*Graph, error) {
+	ccall.Agclearerrors()
 	graph, err := ccall.Agmemread(string(bytes))
 	if err != nil {
 		return nil, err
@@ -113,6 +114,7 @@ func ParseFile(path string) (*Graph, error) {
 	if err != nil {
 		return nil, err
 	}
+	ccall.Agclearerrors()
 	graph, err := ccall.Agmemread(string(file))
 	if err != nil {
 		return nil, err

graphviz_test.go

@@ -2,6 +2,8 @@ package graphviz_test
 
 import (
 	"bytes"
+	"io/ioutil"
+	"os"
 	"testing"
 
 	"github.com/goccy/go-graphviz"
@@ -80,3 +82,70 @@ func TestGraphviz_Image(t *testing.T) {
 		})
 	})
 }
+
+func TestParseBytes(t *testing.T) {
+	type test struct {
+		input          string
+		expected_valid bool
+	}
+
+	tests := []test{
+		{input: "graph test { a -- b }", expected_valid: true},
+		{input: "graph test { a -- b", expected_valid: false},
+		{input: "graph test { a -- b }", expected_valid: true},
+		{input: "graph test { a -- }", expected_valid: false},
+		{input: "graph test { a -- c }", expected_valid: true},
+		{input: "graph test { a - b }", expected_valid: false},
+		{input: "graph test { d -- e }", expected_valid: true},
+	}
+
+	for i, test := range tests {
+		_, err := graphviz.ParseBytes([]byte(test.input))
+		actual_valid := err == nil
+		if actual_valid != test.expected_valid {
+			t.Errorf("Test %d of TestParseBytes failed. Parsing error: %+v", i+1, err)
+		}
+	}
+}
+
+func TestParseFile(t *testing.T) {
+	type test struct {
+		input          string
+		expected_valid bool
+	}
+
+	tests := []test{
+		{input: "graph test { a -- b }", expected_valid: true},
+		{input: "graph test { a -- b", expected_valid: false},
+		{input: "graph test { a -- b }", expected_valid: true},
+		{input: "graph test { a -- }", expected_valid: false},
+		{input: "graph test { a -- c }", expected_valid: true},
+		{input: "graph test { a - b }", expected_valid: false},
+		{input: "graph test { d -- e }", expected_valid: true},
+	}
+
+	createTempFile := func(t *testing.T, content string) *os.File {
+		file, err := ioutil.TempFile("", "*")
+		if err != nil {
+			t.Fatalf("There was an error creating a temporary file. Error: %+v", err)
+			return nil
+		}
+		_, err = file.WriteString(content)
+		if err != nil {
+			t.Fatalf("There was an error writing '%s' to a temporary file. Error: %+v", content, err)
+			return nil
+		}
+		return file
+	}
+
+	for i, test := range tests {
+		tmpfile := createTempFile(t, test.input)
+		defer os.Remove(tmpfile.Name())
+
+		_, err := graphviz.ParseFile(tmpfile.Name())
+		actual_valid := err == nil
+		if actual_valid != test.expected_valid {
+			t.Errorf("Test %d of TestParseFile failed. Parsing error: %+v", i+1, err)
+		}
+	}
+}

internal/ccall/cgraph.go

@@ -1182,6 +1182,10 @@ func Agerr(msg string) {
 	C.free(unsafe.Pointer(s))
 }
 
+func Agclearerrors() {
+	C.agclearerrors()
+}
+
 func init() {
 	C.agseterr(C.AGMAX)
 }

internal/ccall/cgraph/agerror.c

@@ -2,7 +2,7 @@
 /* vim:set shiftwidth=4 ts=8: */
 
 /*************************************************************************
- * Copyright (c) 2011 AT&T Intellectual Property 
+ * Copyright (c) 2011 AT&T Intellectual Property
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -59,7 +59,7 @@ char *aglasterr()
 }
 
 /* userout:
- * Report messages using a user-supplied write function 
+ * Report messages using a user-supplied write function
  */
 static void
 userout (agerrlevel_t level, const char *fmt, va_list args)
@@ -169,10 +169,17 @@ void agwarningf(const char *fmt, ...)
 
 int agerrors() { return agmaxerr; }
 
-int agreseterrors() 
-{ 
+int agreseterrors()
+{
     int rc = agmaxerr;
     agmaxerr = 0;
-    return rc; 
+    return rc;
 }
 
+void agclearerrors()
+{
+    if (agerrout)
+        fclose(agerrout);
+    agerrout = NULL;
+    aglast = 0;
+}

internal/ccall/cgraph/cgraph.h

@@ -2,7 +2,7 @@
 /* vim:set shiftwidth=4 ts=8: */
 
 /*************************************************************************
- * Copyright (c) 2011 AT&T Intellectual Property 
+ * Copyright (c) 2011 AT&T Intellectual Property
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -388,6 +388,7 @@ extern void agerrorf(const char *fmt, ...);
 extern void agwarningf(const char *fmt, ...);
 extern int agerrors(void);
 extern int agreseterrors(void);
+extern void agclearerrors(void);
 extern agusererrf agseterrf(agusererrf);
 
 /* data access macros */