// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package ld

import (
	"cmd/link/internal/loader"
	"cmd/link/internal/sym"
	"encoding/binary"
	"fmt"
	"os"
)

var atExitFuncs []func()

func AtExit(f func()) {
	atExitFuncs = append(atExitFuncs, f)
}

// runAtExitFuncs runs the queued set of AtExit functions.
func runAtExitFuncs() {
	for i := len(atExitFuncs) - 1; i >= 0; i-- {
		atExitFuncs[i]()
	}
	atExitFuncs = nil
}

// Exit exits with code after executing all atExitFuncs.
func Exit(code int) {
	runAtExitFuncs()
	os.Exit(code)
}

// Exitf logs an error message then calls Exit(2).
func Exitf(format string, a ...interface{}) {
	fmt.Fprintf(os.Stderr, os.Args[0]+": "+format+"\n", a...)
	nerrors++
	Exit(2)
}

// afterErrorAction updates 'nerrors' on error and invokes exit or
// panics in the proper circumstances.
func afterErrorAction() {
	nerrors++
	if *flagH {
		panic("error")
	}
	if nerrors > 20 {
		Exitf("too many errors")
	}
}

// Errorf logs an error message.
//
// If more than 20 errors have been printed, exit with an error.
//
// Logging an error means that on exit cmd/link will delete any
// output file and return a non-zero error code.
func Errorf(s *sym.Symbol, format string, args ...interface{}) {
	if s != nil {
		format = s.Name + ": " + format
	}
	format += "\n"
	fmt.Fprintf(os.Stderr, format, args...)
	afterErrorAction()
}

// Errorf method logs an error message.
//
// If more than 20 errors have been printed, exit with an error.
//
// Logging an error means that on exit cmd/link will delete any
// output file and return a non-zero error code.
func (ctxt *Link) Errorf(s loader.Sym, format string, args ...interface{}) {
	if ctxt.loader != nil {
		ctxt.loader.Errorf(s, format, args...)
		return
	}
	// Note: this is not expected to happen very often.
	format = fmt.Sprintf("sym %d: %s", s, format)
	format += "\n"
	fmt.Fprintf(os.Stderr, format, args...)
	afterErrorAction()
}

func artrim(x []byte) string {
	i := 0
	j := len(x)
	for i < len(x) && x[i] == ' ' {
		i++
	}
	for j > i && x[j-1] == ' ' {
		j--
	}
	return string(x[i:j])
}

func stringtouint32(x []uint32, s string) {
	for i := 0; len(s) > 0; i++ {
		var buf [4]byte
		s = s[copy(buf[:], s):]
		x[i] = binary.LittleEndian.Uint32(buf[:])
	}
}

// contains reports whether v is in s.
func contains(s []string, v string) bool {
	for _, x := range s {
		if x == v {
			return true
		}
	}
	return false
}

// implements sort.Interface, for sorting symbols by name.
type byName []*sym.Symbol

func (s byName) Len() int           { return len(s) }
func (s byName) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
func (s byName) Less(i, j int) bool { return s[i].Name < s[j].Name }