autogenpb/protoParse.go

package main

// auto run protoc with the correct args

import (
	"bufio"
	"fmt"
	"os"
	"strings"

	"go.wit.com/log"
	"golang.org/x/text/cases"
	"golang.org/x/text/language"
)

// this parses the .proto file and handles anything with `autogenpb: `

// does the fruit.proto file have "message Fruits"
func (pb *Files) hasPluralMessage(f *File) error {
	file, err := os.Open(f.Filename)
	if err != nil {
		return err
	}
	defer file.Close()
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()

		base := cases.Title(language.English, cases.NoLower).String(f.Filebase)
		prefix := "message " + base + "s {" // to conform, it must have an added 's'
		if !strings.HasPrefix(line, prefix) {
			// log.Info("nope", prefix, "line", line)
			// nope, not this line
			continue
		}
		// found the matching message
		f.Bases = f.parseForMessage(line)

		line = scanner.Text()
		fields := strings.Fields(line)
		if fields[0] == "string" && fields[1] != "uuid" {
			return fmt.Errorf("proto file does not have a UUID")
		}
		// ok, uuid is here
		f.Uuid = line
		log.Info("found UUID:", line)

		line = scanner.Text()
		fields = strings.Fields(line)
		if fields[0] == "string" && fields[1] != "version" {
			return fmt.Errorf("proto file does not have a version")
		}
		// found "version", the .proto file conforms
		f.Version = line
		log.Info("found Version:", line)
		return nil
	}
	return fmt.Errorf("proto file error %s", f.Filename)
}

func (pb *Files) protoParse(f *File) error {
	// does the file conform to the standard? (also reads in UUID & Version)
	if err := pb.hasPluralMessage(f); err != nil {
		return err
	}
	log.Info(f.Filename, "is valid so far")

	// read in the .proto file
	data, err := os.ReadFile(f.Filename)
	if err != nil {
		return err
	}

	var curmsg *MsgName

	// parse the proto file for message struct names
	for _, line := range strings.Split(string(data), "\n") {
		base := cases.Title(language.English, cases.NoLower).String(f.Filebase)
		if strings.HasPrefix(line, "message ") {
			curmsg = f.parseForMessage(line)
			prefix := "message " + base + " {" // only look for this for now
			if strings.HasPrefix(line, prefix) {
				f.Base = curmsg
				f.MsgNames = append(f.MsgNames, curmsg)
			} else {
				f.MsgNames = append(f.MsgNames, curmsg)
			}
		}
		if strings.HasPrefix(line, "}") {
			curmsg = nil
		}
		if curmsg == nil {
			// can't contiue on nil below here
			continue
		}

		parts := strings.Fields(line)
		msgvar := parseMsgVar(line)
		if msgvar == nil {
			// log.Info("Junk in .proto file? line did not contain a message var:", line)
			continue
		}

		if strings.Contains(line, "autogenpb:sort") {
			newS := cases.Title(language.English, cases.NoLower).String(parts[1])
			log.Info("Addded Sort:", newS, "in struct", curmsg.Name)
			curmsg.Sort = append(curmsg.Sort, newS)
			msgvar.HasSort = true
		}

		if strings.Contains(line, "autogenpb:unique") {
			newU := parts[1]
			newU = cases.Title(language.English, cases.NoLower).String(newU)
			log.Info("Added Unique:", newU, "in struct", curmsg.Name)
			curmsg.Unique = append(curmsg.Unique, newU)
			msgvar.HasUnique = true
		}
		curmsg.Vars = append(curmsg.Vars, msgvar)
	}
	return nil
}

func parseMsgVar(line string) *MsgVar {
	if strings.Contains(line, "//") {
		parts := strings.Split(line, "//")
		if len(parts) == 0 {
			// log.Info("parseMsgVar() nothing line", line)
			return nil
		}
		line = parts[0]
	}
	parts := strings.Fields(line)
	if len(parts) < 3 {
		// log.Info("parseMsgVar() len < 3", parts)
		return nil
	}
	if parts[0] == "message" {
		// this is the struct
		return nil
	}
	v := new(MsgVar)
	if parts[0] == "repeated" {
		v.IsRepeated = true
		v.VarType = parts[1]
		v.VarName = parts[2]
		return v
	}
	v.VarType = parts[0]
	v.VarName = parts[1]
	return v
}

// looks for mutex and marshal entries
func (f *File) parseForMessage(line string) *MsgName {
	fields := strings.Fields(line)
	if fields[0] != "message" {
		return nil
	}
	msgName := cases.Title(language.English, cases.NoLower).String(fields[1])
	log.Info("found messge:", msgName)
	msg := new(MsgName)
	msg.Name = msgName
	msg.Lockname = f.Filebase + "Mu" // this should be lowercase. do not export the Mutex

	if strings.Contains(line, "`autogenpb:mutex`") {
		msg.DoMutex = true
		log.Info("Added Mutex=true:", msg.Name)
	}
	if strings.Contains(line, "`autogenpb:marshal`") {
		msg.DoMarshal = true
		log.Info("Added Marshal=true:", msg.Name)
	}
	return msg
}