cmd/godb/main.go

@@ -9,23 +9,29 @@ import (
 )
 
 type metaCommandResults int
-type prepareResults int
-type statementType int
 
 const (
 	metaCommandSuccess metaCommandResults = iota
 	metaCommandUnrecognised
+)
+
+type prepareResults int
+
+const (
 	prepareSuccess prepareResults = iota
 	prepareUnrecognised
 	prepareSyntaxError
+)
+
+type statementType int
+
+const (
 	statementSelect statementType = iota
 	statementInsert
 )
 
 type inputBuffer struct {
 	buffer string
-	bufferLength int
-	inputLength  int
 }
 
 type row struct {
@@ -39,7 +45,7 @@ type statement struct {
 	row   row
 }
 
-func doMetaCommands(inputBuffer inputBuffer) metaCommandResults {
+func doMetaCommands(inputBuffer *inputBuffer) metaCommandResults {
 	metacommand := metaCommandUnrecognised
 	if inputBuffer.buffer == ".exit" {
 		fmt.Println("bye!")
@@ -50,9 +56,9 @@ func doMetaCommands(inputBuffer inputBuffer) metaCommandResults {
 	return metacommand
 }
 
-func prepareStatements(inputBuffer inputBuffer, statement *statement) prepareResults {
-	if strings.Split(inputBuffer.buffer, " ")[0] == "insert" {
-		argsAssigned, err := fmt.Sscanf(inputBuffer.buffer, "insert %v %s %s", &statement.row.id, &statement.row.username, &statement.row.email)
+func prepareStatements(inputBuffer *inputBuffer, statement *statement) prepareResults {
+	if strings.HasPrefix(inputBuffer.buffer, "insert") {
+		argsAssigned, err := fmt.Sscanf(inputBuffer.buffer, "insert %d %s %s", &statement.row.id, &statement.row.username, &statement.row.email)
 		if err != nil {
 			fmt.Println("error parsing insert statement")
 			fmt.Println(err.Error())
@@ -63,7 +69,7 @@ func prepareStatements(inputBuffer inputBuffer, statement *statement) prepareRes
 		statement.stype = statementInsert
 		return prepareSuccess
 	}
-	if strings.Split(inputBuffer.buffer, " ")[0] == "select" {
+	if strings.HasPrefix(inputBuffer.buffer, "select") {
 		statement.stype = statementSelect
 		return prepareSuccess
 	}
@@ -74,57 +80,37 @@ func executeStatement(statement *statement) {
 	switch statement.stype {
 	case statementInsert:
 		fmt.Println("This is where the logic of insert statement should go")
-		break
 	case statementSelect:
 		fmt.Println("This is where the logic of select statement should go")
-		break
 	}
 }
 
-func createInputBuffer() inputBuffer {
-	newInputBuffer := inputBuffer{"", 0, 0}
-	return newInputBuffer
+func createInputBuffer() *inputBuffer {
+	return &inputBuffer{""}
 }
 
 func printConsole() {
 	fmt.Print("godb > ")
 }
 
-func readConsole(inputBuffer inputBuffer) inputBuffer {
-	var stdin *bufio.Reader
-	var line []rune
-	stdin = bufio.NewReader(os.Stdin)
-	for {
-		c, _, err := stdin.ReadRune()
-		if err == io.EOF || c == '\n' {
-			break
-		}
-		if err != nil {
-			fmt.Println("Error reading input")
+func readConsole(inputBuffer *inputBuffer, stdin *bufio.Reader) *inputBuffer {
+	line, err := stdin.ReadString('\n')
+	if err != nil && err != io.EOF {
+		fmt.Println("Error reading input", err)
 		os.Exit(1)
 	}
-		line = append(line, c)
-	}
-	inputBuffer.buffer = string(line)
-	bytesRead := len(inputBuffer.buffer)
-	if bytesRead <= 0 {
-		fmt.Println("Error reading input")
-		os.Exit(1)
-	}
-	inputBuffer.bufferLength = len(inputBuffer.buffer)
-	inputBuffer.inputLength = bytesRead - 1
-
+	inputBuffer.buffer = strings.TrimSpace(line)
 	return inputBuffer
 }
 
 func main() {
+	var stdin = bufio.NewReader(os.Stdin)
 	inputBuffer := createInputBuffer()
 	statement := statement{0, row{0, "", ""}}
-	condition := true
-	for condition {
+	for {
 		printConsole()
-		inputBuffer = readConsole(inputBuffer)
-		if strings.Split(inputBuffer.buffer, "")[0] == "." {
+		inputBuffer = readConsole(inputBuffer, stdin)
+		if strings.HasPrefix(inputBuffer.buffer, ".") {
 			switch doMetaCommands(inputBuffer) {
 			case metaCommandSuccess:
 				continue
@@ -136,7 +122,7 @@ func main() {
 
 		switch prepareStatements(inputBuffer, &statement) {
 		case prepareSuccess:
-			break
+			//todo
 		case prepareUnrecognised:
 			fmt.Printf("Unrecognised keyword at the start of '%s'.\n", inputBuffer.buffer)
 			continue