From 7f4e5c0ef13b961f5ce5b60d09fac466c3ef7926 Mon Sep 17 00:00:00 2001
From: sawka <mike.sawka@gmail.com>
Date: Wed, 16 Nov 2022 22:17:38 -0800
Subject: [PATCH] checkpoint, starting extend

---
 pkg/shparse/extend.go  | 152 +++++++++++++++++++++++++++++++++++++++++
 pkg/shparse/shparse.go |  14 ++--
 pkg/utilfn/utilfn.go   |   2 +
 3 files changed, 161 insertions(+), 7 deletions(-)
 create mode 100644 pkg/shparse/extend.go

diff --git a/pkg/shparse/extend.go b/pkg/shparse/extend.go
new file mode 100644
index 000000000..457a454dd
--- /dev/null
+++ b/pkg/shparse/extend.go
@@ -0,0 +1,152 @@
+package shparse
+
+import (
+	"bytes"
+	"fmt"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/scripthaus-dev/sh2-server/pkg/utilfn"
+)
+
+var noEscChars []bool
+var specialEsc []string
+
+func init() {
+	noEscChars = make([]bool, 256)
+	for ch := 0; ch < 256; ch++ {
+		if (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') ||
+			ch == '-' || ch == '.' || ch == '/' || ch == ':' || ch == '=' {
+			noEscChars[byte(ch)] = true
+		}
+	}
+	specialEsc = make([]string, 256)
+	specialEsc[0x7] = "\\a"
+	specialEsc[0x8] = "\\b"
+	specialEsc[0x9] = "\\t"
+	specialEsc[0xa] = "\\n"
+	specialEsc[0xb] = "\\v"
+	specialEsc[0xc] = "\\f"
+	specialEsc[0xd] = "\\r"
+	specialEsc[0x1b] = "\\E"
+}
+
+func getUtf8Literal(ch rune) string {
+	var buf bytes.Buffer
+	var runeArr [utf8.UTFMax]byte
+	barr := runeArr[:]
+	byteLen := utf8.EncodeRune(barr, ch)
+	for i := 0; i < byteLen; i++ {
+		buf.WriteString("\\x")
+		buf.WriteByte(utilfn.HexDigits[barr[i]/16])
+		buf.WriteByte(utilfn.HexDigits[barr[i]%16])
+	}
+	return buf.String()
+}
+
+func (w *wordType) writeString(s string) {
+	for _, ch := range s {
+		w.writeRune(ch)
+	}
+}
+
+func (w *wordType) writeRune(ch rune) {
+	if w.Type == WordTypeLit {
+		w.Raw = append(w.Raw, ch)
+		return
+	}
+	if w.Type == WordTypeDQ || w.Type == WordTypeDDQ || w.Type == WordTypeSimpleVar || w.Type == WordTypeVarBrace || w.Type == WordTypeSQ || w.Type == WordTypeDSQ {
+		w.Raw = append(w.Raw[0:len(w.Raw)-1], ch, w.Raw[len(w.Raw)-1])
+		return
+	}
+	panic(fmt.Sprintf("cannot extend type %q", w.Type))
+}
+
+func (w *wordType) cloneRaw() {
+	if len(w.Raw) == 0 {
+		return
+	}
+	buf := make([]rune, 0, len(w.Raw))
+	w.Raw = append(buf, w.Raw...)
+}
+
+type extendContext struct {
+	QC        quoteContext
+	Rtn       []*wordType
+	CurWord   *wordType
+	Intention string
+}
+
+func makeExtendContext(qc quoteContext, w *wordType, intention string) *extendContext {
+	rtn := &extendContext{QC: qc, Intention: intention}
+	if w != nil {
+		w.cloneRaw()
+		rtn.Rtn = []*wordType{w}
+		rtn.CurWord = w
+	}
+	return rtn
+}
+
+func (ec *extendContext) appendWord(w *wordType) {
+	ec.Rtn = append(ec.Rtn, w)
+	ec.CurWord = w
+}
+
+func (ec *extendContext) extend(ch rune) {
+	if ch == 0 {
+		return
+	}
+	if ec.CurWord == nil {
+		ec.CurWord = &wordType{Type: WordTypeLit, QC: ec.QC}
+		ec.Rtn = append(ec.Rtn, ec.CurWord)
+	}
+	switch ec.CurWord.Type {
+	case WordTypeSimpleVar:
+
+	case WordTypeDQ, WordTypeDDQ:
+
+	case WordTypeVarBrace:
+
+	case WordTypeSQ:
+		ec.extendSQ(ch)
+
+	case WordTypeDSQ:
+
+	case WordTypeLit:
+
+	default:
+
+	}
+}
+
+func getSpecialEscape(ch rune) string {
+	if ch > unicode.MaxASCII {
+		return ""
+	}
+	return specialEsc[byte(ch)]
+}
+
+func (ec *extendContext) extendSQ(ch rune) {
+	if ch == 0 {
+		return
+	}
+	if ch == '\'' {
+		litWord := &wordType{Type: WordTypeLit, QC: ec.QC}
+		litWord.Raw = []rune{'\\', '\''}
+		ec.appendWord(litWord)
+	}
+	if ch > unicode.MaxASCII || !unicode.IsPrint(ch) {
+		dsqWord := &wordType{Type: WordTypeDSQ, QC: ec.QC}
+		dsqWord.Raw = []rune{'$', '\'', '\''}
+		ec.appendWord(dsqWord)
+		sesc := getSpecialEscape(ch)
+		if sesc != "" {
+			dsqWord.writeString(sesc)
+			return
+		} else {
+			utf8Lit := getUtf8Literal(ch)
+			dsqWord.writeString(utf8Lit)
+		}
+	}
+	ec.CurWord.writeRune(ch)
+}
diff --git a/pkg/shparse/shparse.go b/pkg/shparse/shparse.go
index 0f55bab8a..2e71fc072 100644
--- a/pkg/shparse/shparse.go
+++ b/pkg/shparse/shparse.go
@@ -77,20 +77,20 @@ import (
 
 const (
 	WordTypeRaw       = "raw"
-	WordTypeLit       = "lit"
+	WordTypeLit       = "lit"  // (can-extend)
 	WordTypeOp        = "op"   // single: & ; | ( ) < > \n  multi(2): && || ;; << >> <& >& <> >| ((  multi(3): <<-    ('((' requires special processing)
 	WordTypeKey       = "key"  // if then else elif fi do done case esac while until for in { } ! (( [[
-	WordTypeSimpleVar = "svar" // simplevar $
 	WordTypeGroup     = "grp"  // contains other words e.g. "hello"foo'bar'$x
+	WordTypeSimpleVar = "svar" // simplevar $ (can-extend)
 
-	WordTypeDQ       = "dq"   // "    (quote-context)
-	WordTypeDDQ      = "ddq"  // $"   (quote-context)
-	WordTypeVarBrace = "varb" // ${   (quote-context)
+	WordTypeDQ       = "dq"   // "    (quote-context) (can-extend)
+	WordTypeDDQ      = "ddq"  // $"   (quote-context) (can-extend)
+	WordTypeVarBrace = "varb" // ${   (quote-context) (can-extend)
 	WordTypeDP       = "dp"   // $(   (quote-context)
 	WordTypeBQ       = "bq"   // `    (quote-context)
 
-	WordTypeSQ  = "sq"  // '
-	WordTypeDSQ = "dsq" // $'
+	WordTypeSQ  = "sq"  // '     (can-extend)
+	WordTypeDSQ = "dsq" // $'    (can-extend)
 	WordTypeDPP = "dpp" // $((   (internals not parsed)
 	WordTypePP  = "pp"  // ((    (internals not parsed)
 	WordTypeDB  = "db"  // $[    (internals not parsed)
diff --git a/pkg/utilfn/utilfn.go b/pkg/utilfn/utilfn.go
index 35db1c4df..fcce5845d 100644
--- a/pkg/utilfn/utilfn.go
+++ b/pkg/utilfn/utilfn.go
@@ -5,6 +5,8 @@ import (
 	"strings"
 )
 
+var HexDigits = []byte{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}
+
 func GetStrArr(v interface{}, field string) []string {
 	if v == nil {
 		return nil