Re: [PATCH v2 2/2] mailinfo: unescape quoted-pair in header fields

Kevin Daudt [off-list ref] writes:

+static void unquote_quoted_string(struct strbuf *line)
+{
+	const char *in = strbuf_detach(line, NULL);
+	int c, take_next_literally = 0;
+	int found_error = 0;
+
+	/*
+	 * Stores the character that started the escape mode so that we know what
+	 * character will stop it
+	 */
+	char escape_context = 0;
+
+	while ((c = *in++) != 0) {
+		if (take_next_literally) {
+			take_next_literally = 0;
+		} else {
+			switch (c) {
+			case '"':
+				if (!escape_context)
+					escape_context = '"';
+				else if (escape_context == '"')
+					escape_context = 0;
+				continue;
+			case '\\':
+				if (escape_context) {
+					take_next_literally = 1;
+					continue;
+				}
+				break;
+			case '(':
+				if (!escape_context)
+					escape_context = '(';
+				break;
+			case ')':
+				if (escape_context == '(')
+					escape_context = 0;
+				break;
+			}
+		}
+
+		strbuf_addch(line, c);
+	}
+}

The additional comment makes it very clear what is going on.

Is it an event unusual enough that is worth warning() about if we
have either take_next_literally or escape_context set to non-NUL
upon leaving the loop, I wonder?

Will queue.  Thanks.