implement nginx/encoder + decode->encode test

internal/cnf/parser/nginx/decoder.go

@@ -2,29 +2,11 @@ package nginx
 
 import (
 	"bufio"
-	"fmt"
 	"io"
 	"regexp"
 	"strings"
 )
 
-// ErrNullReceiver is raised when a null receiver is provided
-var ErrNullReceiver = fmt.Errorf("receiver must not be null")
-
-// ErrInvalidReceiver is raised when an invalid receiver is provided
-var ErrInvalidReceiver = fmt.Errorf("receiver must be compatible with *[]*Line")
-
-// ErrUnexpectedSectionClose is raised when reading a section close '}' without an
-// open section
-var ErrUnexpectedSectionClose = fmt.Errorf("unexpected section close")
-
-// ErrUnclosedSection is raised when there is unclosed sections reaching the end
-// of the file
-var ErrUnclosedSection = fmt.Errorf("unclosed section")
-
-// ErrInvalidSyntax is raised when a line cannot be understood
-var ErrInvalidSyntax = fmt.Errorf("invalid syntax")
-
 // decoder implements parser.Decoder
 type decoder struct{ reader io.Reader }
 

internal/cnf/parser/nginx/decoder_test.go

@@ -54,8 +54,7 @@ func TestEachLineType(t *testing.T) {
 	for i, test := range tests {
 
 		// 1. create reader
-		parser := new(nginx)
-		decoder := parser.NewDecoder(strings.NewReader(test.Raw))
+		decoder := NewDecoder(strings.NewReader(test.Raw))
 
 		// 2. Decode
 		receiver := new(nginx)
@@ -114,8 +113,7 @@ func TestNestedSections(t *testing.T) {
 	for i, test := range tests {
 
 		// 1. create reader
-		parser := new(nginx)
-		decoder := parser.NewDecoder(strings.NewReader(test.Raw))
+		decoder := NewDecoder(strings.NewReader(test.Raw))
 
 		// 2. Decode
 		receiver := new(nginx)

internal/cnf/parser/nginx/encoder.go

@@ -1,6 +1,7 @@
 package nginx
 
 import (
+	"fmt"
 	"io"
 )
 
@@ -22,5 +23,91 @@ func (e *encoder) SetIndent(prefix, indent string) {
 }
 
 func (e *encoder) Encode(v interface{}) error {
+	// check 'v'
+	vcast, ok := v.(*nginx)
+	if !ok {
+		return ErrInvalidReceiver
+	}
+
+	// empty config
+	if len(vcast.Lines) < 1 {
+		return nil
+	}
+
+	// actual indentation level
+	indent := 0
+
+	// actual lines to write
+	stack := make([]*Line, 0)
+
+	// push nginx.Lines in reverse order
+	for l := len(vcast.Lines) - 1; l >= 0; l-- {
+		stack = append(stack, vcast.Lines[l])
+	}
+
+	for len(stack) > 0 {
+
+		// pop stack
+		line := stack[len(stack)-1]
+		stack = stack[:len(stack)-1]
+
+		// line representation
+		repr := make([]byte, 0)
+
+		if line == nil { // section end
+			indent--
+		}
+
+		// 1. add indentation
+		repr = append(repr, []byte(e.prefix)...)
+		for i := 0; i < indent; i++ {
+			repr = append(repr, []byte(e.indent)...)
+		}
+
+		// 2. section end
+		if line == nil {
+			repr = append(repr, []byte("}\n\n")...)
+			// Note: new line after section for readability
+			indent--
+
+			// 3. comments
+		} else if line.Type == COMMENT {
+
+			repr = append(repr, []byte(fmt.Sprintf("#%s\n", line.Components[0]))...)
+		} else if line.Type == COLONCOMMENT {
+			repr = append(repr, []byte(fmt.Sprintf(";%s\n", line.Components[0]))...)
+
+			// 4.assignments
+		} else if line.Type == ASSIGNMENT {
+			repr = append(repr, []byte(fmt.Sprintf("%s %s;\n", line.Components[0], line.Components[1]))...)
+
+			// 5. include
+		} else if line.Type == INCLUDE {
+			repr = append(repr, []byte(fmt.Sprintf("include %s;\n", line.Components[0]))...)
+
+			// 6. section
+		} else {
+			// push to stack
+			stack = append(stack, nil)
+
+			// push children lines in reverse order
+			if len(line.Lines) > 0 {
+				for l := len(line.Lines); l > 0; l-- {
+					stack = append(stack, line.Lines[l])
+				}
+			}
+
+			repr = append(repr, []byte(fmt.Sprintf("%s {\n", line.Components[0]))...)
+			indent++
+
+		}
+
+		_, err := e.writer.Write(repr)
+		if err != nil {
+			return err
+		}
+
+	}
+
 	return nil
 }

internal/cnf/parser/nginx/encoder_test.go

@@ -0,0 +1,102 @@
+package nginx
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestDecodeEncode(t *testing.T) {
+	tests := []struct {
+		Input  string
+		Output string
+	}{
+		{"key value;\n", "key value;\n"},
+		{"key    value;\n", "key value;\n"},
+		{"key  \t  value;\n", "key value;\n"},
+		{"key\tvalue;\n", "key value;\n"},
+		{"ke-y value;\n", "ke-y value;\n"},
+		{"ke_y value;\n", "ke_y value;\n"},
+		{"key value;  \n", "key value;\n"},
+		{"key value;\t\n", "key value;\n"},
+		{"\tkey value;\n", "key value;\n"},
+		{"  \t  key value;\n", "key value;\n"},
+
+		{"include ./file/*.conf;\n", "include ./file/*.conf;\n"},
+		{"include ./file/*.conf;  \n", "include ./file/*.conf;\n"},
+		{"include ./file/*.conf;\t\n", "include ./file/*.conf;\n"},
+		{"\tinclude ./file/*.conf;\n", "include ./file/*.conf;\n"},
+		{"  \t  include ./file/*.conf;\n", "include ./file/*.conf;\n"},
+
+		{"sectionname {\n}\n", "sectionname {\n}\n\n"},
+		{"section-name {\n}\n", "section-name {\n}\n\n"},
+		{"section_name {\n}\n", "section_name {\n}\n\n"},
+		{"sectionname {  \n}\n", "sectionname {\n}\n\n"},
+		{"sectionname {\t\n}\n", "sectionname {\n}\n\n"},
+		{"\tsectionname {\n}\n", "sectionname {\n}\n\n"},
+		{"  \t  sectionname {\n}\n", "sectionname {\n}\n\n"},
+
+		{"#some comment\n", "#some comment\n"},
+		{"#some\tcomment\n", "#some\tcomment\n"},
+		{"# some  comment  \n", "# some  comment\n"},
+		{"# some comment \t\n", "# some comment\n"},
+		{"\t# some comment {\n", "# some comment {\n"},
+
+		{";some comment\n", ";some comment\n"},
+		{"; some\tcomment\n", "; some\tcomment\n"},
+		{"; some   comment\n", "; some   comment\n"},
+		{"; some comment  \n", "; some comment\n"},
+		{"; some comment \t\n", "; some comment\n"},
+		{"\t; some comment {\n", "; some comment {\n"},
+	}
+
+	for i, test := range tests {
+
+		// create reader/writer
+		r, w := strings.NewReader(test.Input), &bytes.Buffer{}
+
+		// parse input
+		receiver := new(nginx)
+		decoder := NewDecoder(r)
+		if err := decoder.Decode(receiver); err != nil {
+			t.Errorf("[%d] unexpected error <%s>", i, err)
+			continue
+		}
+
+		// encode back to writer
+		encoder := NewEncoder(w)
+		encoder.SetIndent("", "\t")
+		if err := encoder.Encode(receiver); err != nil {
+			t.Errorf("[%d] unexpected error <%s>", i, err)
+			continue
+		}
+
+		// check equality
+		if w.String() != test.Output {
+			t.Errorf("[%d] expected '%s', got '%s'", i, escape(test.Output), escape(w.String()))
+		}
+
+	}
+}
+
+func escape(raw string) string {
+
+	escaped := make([]rune, 0)
+
+	for _, char := range raw {
+		if char == '\n' {
+			escaped = append(escaped, []rune("\\n")...)
+		} else if char == '\t' {
+			escaped = append(escaped, []rune("\\t")...)
+		} else if char == '\r' {
+			escaped = append(escaped, []rune("\\r")...)
+
+		} else {
+			escaped = append(escaped, char)
+		}
+
+	}
+
+	return string(escaped)
+
+}

internal/cnf/parser/nginx/errors.go

@@ -5,6 +5,23 @@ import (
 	"git.xdrm.io/go/nix-amer/internal/clifmt"
 )
 
+// ErrNullReceiver is raised when a null receiver is provided
+var ErrNullReceiver = fmt.Errorf("receiver must not be null")
+
+// ErrInvalidReceiver is raised when an invalid receiver is provided
+var ErrInvalidReceiver = fmt.Errorf("receiver must be compatible with *[]*Line")
+
+// ErrUnexpectedSectionClose is raised when reading a section close '}' without an
+// open section
+var ErrUnexpectedSectionClose = fmt.Errorf("unexpected section close")
+
+// ErrUnclosedSection is raised when there is unclosed sections reaching the end
+// of the file
+var ErrUnclosedSection = fmt.Errorf("unclosed section")
+
+// ErrInvalidSyntax is raised when a line cannot be understood
+var ErrInvalidSyntax = fmt.Errorf("invalid syntax")
+
 // LineError wraps errors with a line index
 type LineError struct {
 	Line int

internal/cnf/parser/nginx/nginx.go

@@ -9,10 +9,15 @@ type nginx struct {
 }
 
 // NewDecoder implements parser.T
-func (n *nginx) NewDecoder(r io.Reader) *decoder {
+func NewDecoder(r io.Reader) *decoder {
 	return &decoder{reader: r}
 }
 
+// NewEncoder implements parser.T
+func NewEncoder(w io.Writer) *encoder {
+	return &encoder{writer: w}
+}
+
 // Section returns the section with a given name at the root level
 // nil is returned if no match found
 func (l *nginx) Section(name string) *Line {