shared: refactor nm_utils_parse_next_line() and add tests

- add unit test for nm_utils_parse_next_line()

- as line delimiter also accept "\r\n" and "\r" (beside "\n", "\0" and
  EOF).

- fix returning lines with embedded "\0" characters. The line ends
  on the first "\n" or "\0", whatever comes first. The code before
  didn't ensure that with:

     line_end = memchr (line_start, '\n', *inout_len);
     if (!line_end)
         line_end = memchr (line_start, '\0', *inout_len);

2 files changed, 143 insertions, 25 deletions

diff --git a/shared/nm-glib-aux/nm-shared-utils.c b/shared/nm-glib-aux/nm-shared-utils.c
index 1569662f8c..9fc4e510ac 100644
--- a/shared/nm-glib-aux/nm-shared-utils.c
+++ b/shared/nm-glib-aux/nm-shared-utils.c
@@ -1080,39 +1080,53 @@ nm_utils_parse_next_line (const char **inout_ptr,
                           const char **out_line,
                           gsize *out_line_len)
 {
+	gboolean eol_is_carriage_return;
 	const char *line_start;
-	const char *line_end;
+	gsize line_len;
 
-	g_return_val_if_fail (inout_ptr, FALSE);
-	g_return_val_if_fail (inout_len, FALSE);
-	g_return_val_if_fail (out_line, FALSE);
+	nm_assert (inout_ptr);
+	nm_assert (inout_len);
+	nm_assert (*inout_len == 0 || *inout_ptr);
+	nm_assert (out_line);
+	nm_assert (out_line_len);
 
-	if (*inout_len <= 0)
-		goto error;
+	if (G_UNLIKELY (*inout_len == 0))
+		return FALSE;
 
 	line_start = *inout_ptr;
-	line_end = memchr (line_start, '\n', *inout_len);
-	if (!line_end)
-		line_end = memchr (line_start, '\0', *inout_len);
-	if (!line_end) {
-		line_end = line_start + *inout_len;
-		NM_SET_OUT (inout_len, 0);
-	} else
-		NM_SET_OUT (inout_len, *inout_len - (line_end - line_start) - 1);
 
-	NM_SET_OUT (out_line, line_start);
-	NM_SET_OUT (out_line_len, (gsize) (line_end - line_start));
+	eol_is_carriage_return = FALSE;
+	for (line_len = 0; ; line_len++) {
+		if (line_len >= *inout_len) {
+			/* if we consumed the entire line, we place the pointer at
+			 * one character after the end. */
+			*inout_ptr = &line_start[line_len];
+			*inout_len = 0;
+			goto done;
+		}
+		switch (line_start[line_len]) {
+		case '\r':
+			eol_is_carriage_return = TRUE;
+			/* fall-through*/
+		case '\0':
+		case '\n':
+			*inout_ptr = &line_start[line_len + 1];
+			*inout_len = *inout_len - line_len - 1u;
+			if (   eol_is_carriage_return
+			    && *inout_len > 0
+			    && (*inout_ptr)[0] == '\n') {
+				/* also consume "\r\n" as one. */
+				(*inout_len)--;
+				(*inout_ptr)++;
+			}
+			goto done;
+		}
+	}
 
-	if (*inout_len > 0)
-		NM_SET_OUT (inout_ptr, line_end + 1);
-	else
-		NM_SET_OUT (inout_ptr, NULL);
+done:
+	*out_line = line_start;
+	*out_line_len = line_len;
 	return TRUE;
-
-error:
-	NM_SET_OUT (out_line, NULL);
-	NM_SET_OUT (out_line_len, 0);
-	return FALSE;
 }
 
 /*****************************************************************************/
diff --git a/shared/nm-glib-aux/tests/test-shared-general.c b/shared/nm-glib-aux/tests/test-shared-general.c
index a435e28195..f389770a7a 100644
--- a/shared/nm-glib-aux/tests/test-shared-general.c
+++ b/shared/nm-glib-aux/tests/test-shared-general.c
@@ -773,6 +773,109 @@ test_nm_str_buf (void)
 
 /*****************************************************************************/
 
+static void
+test_nm_utils_parse_next_line (void)
+{
+	const char *data;
+	const char *data0;
+	gsize data_len;
+	const char *line_start;
+	gsize line_len;
+	int i_run;
+	gsize j, k;
+
+	data = NULL;
+	data_len = 0;
+	g_assert (!nm_utils_parse_next_line (&data, &data_len, &line_start, &line_len));
+
+	for (i_run = 0; i_run < 1000; i_run++) {
+		gs_unref_ptrarray GPtrArray *strv = g_ptr_array_new_with_free_func (g_free);
+		gs_unref_ptrarray GPtrArray *strv2 = g_ptr_array_new_with_free_func (g_free);
+		gsize strv_len = nmtst_get_rand_word_length (NULL);
+		nm_auto_str_buf NMStrBuf strbuf = NM_STR_BUF_INIT (0, nmtst_get_rand_bool ());
+
+		/* create a list of random words. */
+		for (j = 0; j < strv_len; j++) {
+			gsize w_len = nmtst_get_rand_word_length (NULL);
+			NMStrBuf w_buf = NM_STR_BUF_INIT (nmtst_get_rand_uint32 () % (w_len + 1), nmtst_get_rand_bool ());
+
+			for (k = 0; k < w_len; k++)
+				nm_str_buf_append_c (&w_buf, '0' + (k % 10));
+			nm_str_buf_maybe_expand (&w_buf, 1, TRUE);
+			g_ptr_array_add (strv, nm_str_buf_finalize (&w_buf, NULL));
+		}
+
+		/* join the list of random words with (random) line delimiters
+		 * ("\0", "\n", "\r" or EOF). */
+		for (j = 0; j < strv_len; j++) {
+			nm_str_buf_append (&strbuf, strv->pdata[j]);
+again:
+			switch (nmtst_get_rand_uint32 () % 5) {
+			case 0:
+				nm_str_buf_append_c (&strbuf, '\0');
+				break;
+			case 1:
+				if (   strbuf.len > 0
+				    && (nm_str_buf_get_str_unsafe (&strbuf))[strbuf.len - 1] == '\r') {
+					/* the previous line was empty and terminated by "\r". We
+					 * must not join with "\n". Retry. */
+					goto again;
+				}
+				nm_str_buf_append_c (&strbuf, '\n');
+				break;
+			case 2:
+				nm_str_buf_append_c (&strbuf, '\r');
+				break;
+			case 3:
+				nm_str_buf_append (&strbuf, "\r\n");
+				break;
+			case 4:
+				/* the last word randomly is delimited or not, but not if the last
+				 * word is "". */
+				if (j + 1 < strv_len) {
+					/* it's not the last word. Retry. */
+					goto again;
+				}
+				g_assert (j == strv_len - 1);
+				if (((const char *) strv->pdata[j])[0] == '\0') {
+					/* if the last word was "", we need a delimiter (to parse it back).
+					 * Retry. */
+					goto again;
+				}
+				/* The final delimiter gets omitted. It's EOF. */
+				break;
+			}
+		}
+
+		data0 = nm_str_buf_get_str_unsafe (&strbuf);
+		if (   !data0
+		    && nmtst_get_rand_bool ()) {
+			nm_str_buf_maybe_expand (&strbuf, 1, TRUE);
+			data0 = nm_str_buf_get_str_unsafe (&strbuf);
+			g_assert (data0);
+		}
+		data_len = strbuf.len;
+		g_assert ((data_len > 0 && data0) || data_len == 0);
+		data = data0;
+		while (nm_utils_parse_next_line (&data, &data_len, &line_start, &line_len)) {
+			g_assert (line_start);
+			g_assert (line_start >= data0);
+			g_assert (line_start < &data0[strbuf.len]);
+			g_assert (!memchr (line_start, '\0', line_len));
+			g_ptr_array_add (strv2, g_strndup (line_start, line_len));
+		}
+		g_assert (data_len == 0);
+		if (data0)
+			g_assert (data == &data0[strbuf.len]);
+		else
+			g_assert (!data);
+
+		g_assert (_nm_utils_strv_cmp_n ((const char *const*) strv->pdata, strv->len, (const char *const*) strv2->pdata, strv2->len) == 0);
+	}
+}
+
+/*****************************************************************************/
+
 NMTST_DEFINE ();
 
 int main (int argc, char **argv)
@@ -794,6 +897,7 @@ int main (int argc, char **argv)
 	g_test_add_func ("/general/test_string_table_lookup", test_string_table_lookup);
 	g_test_add_func ("/general/test_nm_utils_get_next_realloc_size", test_nm_utils_get_next_realloc_size);
 	g_test_add_func ("/general/test_nm_str_buf", test_nm_str_buf);
+	g_test_add_func ("/general/test_nm_utils_parse_next_line", test_nm_utils_parse_next_line);
 
 	return g_test_run ();
 }