From d8f64f516b2dde32a8816abd54b1936db9155bae Mon Sep 17 00:00:00 2001
From: pancake <pancake@nowsecure.com>
Date: Wed, 18 Nov 2020 18:23:44 +0100
Subject: [PATCH] js: fix codegen for multiline strings (#6791)

---
 vlib/v/gen/js/js.v  |   3 +-
 vlib/v/gen/str.v    | 104 +++-----------------------------------------
 vlib/v/util/quote.v |  97 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 104 insertions(+), 100 deletions(-)
 create mode 100644 vlib/v/util/quote.v

diff --git a/vlib/v/gen/js/js.v b/vlib/v/gen/js/js.v
index 1d6f765cd3..cfb5bd7978 100644
--- a/vlib/v/gen/js/js.v
+++ b/vlib/v/gen/js/js.v
@@ -642,7 +642,8 @@ fn (mut g JsGen) expr(node ast.Expr) {
 			g.gen_string_inter_literal(node)
 		}
 		ast.StringLiteral {
-			g.write('"$node.val"')
+			text := node.val.replace('`', '\\`')
+			g.write('`$text`')
 		}
 		ast.StructInit {
 			// `user := User{name: 'Bob'}`
diff --git a/vlib/v/gen/str.v b/vlib/v/gen/str.v
index b72185bbfd..8036b5682d 100644
--- a/vlib/v/gen/str.v
+++ b/vlib/v/gen/str.v
@@ -3,102 +3,8 @@
 module gen
 
 import v.ast
+import v.util
 import v.table
-import strings
-
-const (
-	invalid_escapes = ['(', '{', '$', '`', '.']
-)
-
-fn smart_quote(str string, raw bool) string {
-	len := str.len
-	if len == 0 {
-		return str
-	}
-	mut result := strings.new_builder(0)
-	mut pos := -1
-	mut last := ''
-	// TODO: This should be a single char?
-	mut next := ''
-	mut skip_next := false
-	for {
-		pos = pos + 1
-		if skip_next {
-			skip_next = false
-			pos = pos + 1
-		}
-		if pos >= len {
-			break
-		}
-		if pos + 1 < len {
-			unsafe {
-				next = str.str[pos + 1].str()
-			}
-		}
-		mut current := str
-		mut toadd := str
-		if len > 1 {
-			unsafe {
-				current = str.str[pos].str()
-			}
-			toadd = current
-		}
-		// double quote
-		if current == '"' {
-			toadd = '\\"'
-			current = ''
-		}
-		if current == '\\' {
-			if raw {
-				toadd = '\\\\'
-			} else {
-				// escaped backslash - keep as is
-				if next == '\\' {
-					toadd = '\\\\'
-					skip_next = true
-				} else if next != '' {
-					if raw {
-						toadd = '\\\\' + next
-						skip_next = true
-					}
-					// keep all valid escape sequences
-					else if next !in invalid_escapes {
-						toadd = '\\' + next
-						skip_next = true
-					} else {
-						toadd = next
-						skip_next = true
-					}
-				}
-			}
-		}
-		// keep newlines in string
-		if current == '\n' {
-			toadd = '\\n'
-			current = ''
-		} else if current == '\r' && next == '\n' {
-			toadd = '\r\n'
-			current = ''
-			skip_next = true
-		}
-		// Dolar sign
-		if !raw && current == '$' {
-			if last == '\\' {
-				toadd = r'\$'
-			}
-		}
-		// Windows style new line \r\n
-		if !raw && current == '\r' {
-			if next == '\n' {
-				skip_next = true
-				toadd = '\\n'
-			}
-		}
-		result.write(toadd)
-		last = current
-	}
-	return result.str()
-}
 
 fn (mut g Gen) write_str_fn_definitions() {
 	// _STR function can't be defined in vlib
@@ -213,11 +119,11 @@ string _STR_TMP(const char *fmt, ...) {
 
 fn (mut g Gen) string_literal(node ast.StringLiteral) {
 	if node.is_raw {
-		escaped_val := smart_quote(node.val, true)
+		escaped_val := util.smart_quote(node.val, true)
 		g.write('tos_lit("$escaped_val")')
 		return
 	}
-	escaped_val := smart_quote(node.val, false)
+	escaped_val := util.smart_quote(node.val, false)
 	if g.is_c_call || node.language == .c {
 		// In C calls we have to generate C strings
 		// `C.printf("hi")` => `printf("hi");`
@@ -244,7 +150,7 @@ fn (mut g Gen) string_inter_literal_sb_optimized(call_expr ast.CallExpr) {
 	is_nl := call_expr.name == 'writeln'
 	// println('optimize sb $call_expr.name')
 	for i, val in node.vals {
-		escaped_val := smart_quote(val, false)
+		escaped_val := util.smart_quote(val, false)
 		// if val == '' {
 		// break
 		// continue
@@ -309,7 +215,7 @@ fn (mut g Gen) string_inter_literal(node ast.StringInterLiteral) {
 	mut end_string := false
 	for i, val in node.vals {
 		mut escaped_val := val.replace_each(['%', '%%'])
-		escaped_val = smart_quote(escaped_val, false)
+		escaped_val = util.smart_quote(escaped_val, false)
 		if i >= node.exprs.len {
 			if escaped_val.len > 0 {
 				end_string = true
diff --git a/vlib/v/util/quote.v b/vlib/v/util/quote.v
new file mode 100644
index 0000000000..03439a1159
--- /dev/null
+++ b/vlib/v/util/quote.v
@@ -0,0 +1,97 @@
+module util
+
+import strings
+
+const (
+	invalid_escapes = ['(', '{', '$', '`', '.']
+)
+
+pub fn smart_quote(str string, raw bool) string {
+	len := str.len
+	if len == 0 {
+		return str
+	}
+	mut result := strings.new_builder(0)
+	mut pos := -1
+	mut last := ''
+	// TODO: This should be a single char?
+	mut next := ''
+	mut skip_next := false
+	for {
+		pos = pos + 1
+		if skip_next {
+			skip_next = false
+			pos = pos + 1
+		}
+		if pos >= len {
+			break
+		}
+		if pos + 1 < len {
+			unsafe {
+				next = str.str[pos + 1].str()
+			}
+		}
+		mut current := str
+		mut toadd := str
+		if len > 1 {
+			unsafe {
+				current = str.str[pos].str()
+			}
+			toadd = current
+		}
+		// double quote
+		if current == '"' {
+			toadd = '\\"'
+			current = ''
+		}
+		if current == '\\' {
+			if raw {
+				toadd = '\\\\'
+			} else {
+				// escaped backslash - keep as is
+				if next == '\\' {
+					toadd = '\\\\'
+					skip_next = true
+				} else if next != '' {
+					if raw {
+						toadd = '\\\\' + next
+						skip_next = true
+					}
+					// keep all valid escape sequences
+					else if next !in invalid_escapes {
+						toadd = '\\' + next
+						skip_next = true
+					} else {
+						toadd = next
+						skip_next = true
+					}
+				}
+			}
+		}
+		// keep newlines in string
+		if current == '\n' {
+			toadd = '\\n'
+			current = ''
+		} else if current == '\r' && next == '\n' {
+			toadd = '\r\n'
+			current = ''
+			skip_next = true
+		}
+		// Dolar sign
+		if !raw && current == '$' {
+			if last == '\\' {
+				toadd = r'\$'
+			}
+		}
+		// Windows style new line \r\n
+		if !raw && current == '\r' {
+			if next == '\n' {
+				skip_next = true
+				toadd = '\\n'
+			}
+		}
+		result.write(toadd)
+		last = current
+	}
+	return result.str()
+}