autogenpb/main.go

package main

import (
	"fmt"
	"io"
	"os"
)

var names map[string]string

func main() {
	f, _ := os.OpenFile("test.sort.pb.go", os.O_WRONLY|os.O_CREATE, 0600)
	names = make(map[string]string)
	names["package"] = "testautogen"
	names["lock"] = "gitTagslock"
	names["Base"] = "GitTag"
	names["Bases"] = "GitTags"

	names["base"] = "gitTag"
	names["sortBy"] = "ByPath"
	names["sortKey"] = "Refname"

	header(f, "testautogen")
	syncLock(f, "gitTagslock")
	iterTop(f, "GitTag")
	iterNext(f)
	iterSort(f)
	iterAppend(f)
	iterEnd(f)
}

func header(w io.Writer, name string) {
	fmt.Fprintln(w, "package "+name)
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "// this is becoming a standard format")
	fmt.Fprintln(w, "// todo: autogenerate this from the .proto file?")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "import (")
	fmt.Fprintln(w, "	\"fmt\"")
	fmt.Fprintln(w, "	\"os\"")
	fmt.Fprintln(w, "	\"sort\"")
	fmt.Fprintln(w, "	\"sync\"")
	fmt.Fprintln(w, ")")
	fmt.Fprintln(w, "")
}

func syncLock(w io.Writer, name string) {
	fmt.Fprintln(w, "// bad global lock until I figure out some other plan")
	fmt.Fprintln(w, "var "+name+" sync.RWMutex")
	fmt.Fprintln(w, "")
}

func iterTop(w io.Writer, name string) {
	fmt.Fprintln(w, "type "+name+"Iterator struct {")
	fmt.Fprintln(w, "	sync.RWMutex")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "	packs []*"+name)
	fmt.Fprintln(w, "	index int")
	fmt.Fprintln(w, "}")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "// New"+name+"Iterator initializes a new iterator.")
	fmt.Fprintln(w, "func New"+name+"Iterator(packs []*"+name+") *"+name+"Iterator {")
	fmt.Fprintln(w, "	return &"+name+"Iterator{packs: packs}")
	fmt.Fprintln(w, "}")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "// Scan moves to the next element and returns false if there are no more packs.")
	fmt.Fprintln(w, "// Use Scan() in a loop, similar to a while loop")
	fmt.Fprintln(w, "//")
	fmt.Fprintln(w, "//	for iterator.Scan() ")
	fmt.Fprintln(w, "//		d := iterator.Next(")
	fmt.Fprintln(w, "//		fmt.Println(\"found UUID:\", d.Uuid")
	fmt.Fprintln(w, "//	}")
	fmt.Fprintln(w, "func (it *"+name+"Iterator) Scan() bool {")
	fmt.Fprintln(w, "	if it.index >= len(it.packs) {")
	fmt.Fprintln(w, "		return false")
	fmt.Fprintln(w, "	}")
	fmt.Fprintln(w, "	it.index++")
	fmt.Fprintln(w, "	return true")
	fmt.Fprintln(w, "}")
	fmt.Fprintln(w, "")
}

func iterNext(w io.Writer) {
	fmt.Fprintln(w, "// Next() returns the next thing in the array")
	fmt.Fprintln(w, "func (it *" + names["Base"] + "Iterator) Next() *" + names["Base"] + " {")
	fmt.Fprintln(w, "	if it.packs[it.index-1] == nil {")
	fmt.Fprintln(w, "		for i, d := range it.packs {")
	fmt.Fprintln(w, "			fmt.Println(\"i =\", i, d)")
	fmt.Fprintln(w, "		}")
	fmt.Fprintln(w, "		fmt.Println(\"protobuf autogenpb sort error len =\", len(it.packs))")
	fmt.Fprintln(w, "		fmt.Println(\"protobuf autogenpb sort error next == nil\", it.index, it.index-1)")
	fmt.Fprintln(w, "		os.Exit(-1)")
	fmt.Fprintln(w, "	}")
	fmt.Fprintln(w, "	return it.packs[it.index-1]")
	fmt.Fprintln(w, "}")
	fmt.Fprintln(w, "")
}


func iterSort(w io.Writer) {
	fmt.Fprintln(w, "func (all *" + names["Bases"] + ") All() *" + names["Base"] + "Iterator {")
	fmt.Fprintln(w, "	" + names["base"] + "Pointers := all.selectAll" + names["Base"] + "()")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "	iterator := New" + names["Base"] + "Iterator(" + names["base"] + "Pointers)")
	fmt.Fprintln(w, "	return iterator")
	fmt.Fprintln(w, "}")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "func (all *" + names["Bases"] + ") Sort" + names["sortBy"] + "() *" + names["Base"] + "Iterator {")
	fmt.Fprintln(w, "	packs := all.selectAll" + names["Base"] + "()")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "	sort.Sort(" + names["Base"] + "" + names["sortBy"] + "(packs))")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "	iterator := New" + names["Base"] + "Iterator(packs)")
	fmt.Fprintln(w, "	return iterator")
	fmt.Fprintln(w, "}")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "func (all *" + names["Bases"] + ") Len() int {")
	fmt.Fprintln(w, "	" + names["lock"] + ".RLock()")
	fmt.Fprintln(w, "	defer " + names["lock"] + ".RUnlock()")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "	return len(all." + names["Bases"] + ")")
	fmt.Fprintln(w, "}")
	fmt.Fprintln(w, "")
}

func iterEnd(w io.Writer) {
	fmt.Fprintln(w, "type " + names["Base"] + "" + names["sortBy"] + " []*" + names["Base"] + "")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "func (a " + names["Base"] + "" + names["sortBy"] + ") Len() int           { return len(a) }")
	fmt.Fprintln(w, "func (a " + names["Base"] + "" + names["sortBy"] + ") Less(i, j int) bool { return a[i]." + names["sortKey"] + " < a[j]." + names["sortKey"] + " }")
	fmt.Fprintln(w, "func (a " + names["Base"] + "" + names["sortBy"] + ") Swap(i, j int)      { a[i], a[j] = a[j], a[i] }")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "// safely returns a slice of pointers to the " + names["Base"] + " protobufs")
	fmt.Fprintln(w, "func (all *" + names["Bases"] + ") selectAll" + names["Base"] + "() []*" + names["Base"] + " {")
	fmt.Fprintln(w, "	" + names["lock"] + ".RLock()")
	fmt.Fprintln(w, "	defer " + names["lock"] + ".RUnlock()")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "	// Create a new slice to hold pointers to each " + names["Base"] + "")
	fmt.Fprintln(w, "	var aStuff []*" + names["Base"] + "")
	fmt.Fprintln(w, "	aStuff = make([]*" + names["Base"] + ", len(all." + names["Bases"] + "))")
	fmt.Fprintln(w, "	for i, p := range all." + names["Bases"] + " {")
	fmt.Fprintln(w, "		aStuff[i] = p // Copy pointers for safe iteration")
	fmt.Fprintln(w, "	}")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "	return aStuff")
	fmt.Fprintln(w, "}")
	fmt.Fprintln(w, "")
}

func iterAppend(w io.Writer) {
	fmt.Fprintln(w, "// enforces no duplicate Refname names")
	fmt.Fprintln(w, "func (all *" + names["Bases"] + ") Append(newP *" + names["Base"] + ") bool {")
	fmt.Fprintln(w, "	" + names["lock"] + ".Lock()")
	fmt.Fprintln(w, "	defer " + names["lock"] + ".Unlock()")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "	for _, p := range all." + names["Bases"] + " {")
	fmt.Fprintln(w, "		if p.Refname == newP.Refname {")
	fmt.Fprintln(w, "			return false")
	fmt.Fprintln(w, "		}")
	fmt.Fprintln(w, "	}")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "	all." + names["Bases"] + " = append(all." + names["Bases"] + ", newP)")
	fmt.Fprintln(w, "	return true")
	fmt.Fprintln(w, "}")
	fmt.Fprintln(w, "")
}