unget doesn't respect binary/text mode

doc/cqueues.tex

@@ -695,8 +695,9 @@ \subsubsection{\routine{cqueues.COMMIT}}
 \subsubsection[\fn{socket:fill}]{\fn{socket:fill(size[, timeout])}}
 Fills the input buffer with `size' bytes. Returns true on success, false and an error code on failure.
 
-\subsubsection[{\fn{socket:unget}}]{\fn{socket:unget(string)}}
+\subsubsection[{\fn{socket:unget}}]{\fn{socket:unget(string [, mode])}}
 Writes `string' to the head of the socket input buffer.
+$mode$ should be in the format described at \method{socket:setmode}
 
 \subsubsection[{\fn{socket:pending}}]{\fn{socket:pending()}}
 Returns two numbers---the counts of buffered bytes in the input and output streams. This does not include the bytes in the kernel's buffer.

regress/90-unget-textmode.lua

@@ -0,0 +1,28 @@
+#!/bin/sh
+_=[[
+	. "${0%%/*}/regress.sh"
+	exec runlua "$0" "$@"
+]]
+require"regress".export".*"
+
+local function test_with_mode(str, mode)
+	local c, s = socket.pair()
+	check(s:xwrite(str, "bn"))
+	local foo = c:xread(-99999, mode)
+	check(c:unget(foo, mode))
+	local bar = c:xread(-99999, mode)
+	check(foo == bar, "unget + read does not round trip")
+end
+local function test(str)
+	info("testing: %q", str)
+	test_with_mode(str, "t")
+	test_with_mode(str, "b")
+end
+
+test'test'
+test'test\n'
+test'hi\r\nthere\nworld\r'
+test'\n\n'
+test'foo\r\r\n'
+
+say("OK")

src/socket.c

@@ -26,7 +26,7 @@
 #include <stddef.h>	/* NULL offsetof size_t */
 #include <stdarg.h>	/* va_list va_start va_arg va_end */
 #include <stdlib.h>	/* strtol(3) */
-#include <string.h>	/* memset(3) memchr(3) memcpy(3) memmem(3) */
+#include <string.h>	/* memset(3) memchr(3) memcpy(3) memmem(3) memrchr(3) */
 #include <math.h>	/* NAN */
 #include <errno.h>	/* EBADF ENOTSOCK EOPNOTSUPP EOVERFLOW EPIPE */
 
@@ -2137,12 +2137,30 @@ static lso_nargs_t lso_recv3(lua_State *L) {
 
 static lso_nargs_t lso_unget2(lua_State *L) {
 	struct luasocket *S = lso_checkself(L, 1);
-	const void *src;
-	size_t len;
+	const char *src, *new_base;
+	size_t len, found;
 	struct iovec iov;
-	int error;
+	int mode, error;
 
 	src = luaL_checklstring(L, 2, &len);
+	mode = lso_imode(luaL_optstring(L, 3, ""), S->ibuf.mode);
+
+	if (mode & LSO_TEXT) {
+		/* insert \r before each \n */
+		while ((new_base = memrchr(src, '\n', len))) {
+			found = len - (new_base - src); /* number of bytes found including \n */
+
+			if ((error = fifo_grow(&S->ibuf.fifo, found+1)))
+				goto error;
+
+			fifo_rewind(&S->ibuf.fifo, found+1);
+			fifo_slice(&S->ibuf.fifo, &iov, 0, found+1);
+			memcpy(iov.iov_base+1, new_base, found);
+			((char*)iov.iov_base)[0] = '\r';
+
+			len = new_base - src;
+		}
+	}
 
 	if ((error = fifo_grow(&S->ibuf.fifo, len)))
 		goto error;