xargs: fix -I SUBSTR behaviour

function                                             old     new   delta
process_stdin_with_replace                           165     204     +39

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 24 insertions, 5 deletions

diff --git a/findutils/xargs.c b/findutils/xargs.c
index ff04bfe7c..e2b3527f3 100644
--- a/findutils/xargs.c
+++ b/findutils/xargs.c
@@ -80,9 +80,11 @@
 /* This is a NOEXEC applet. Be very careful! */
 
 
-//#define dbg_msg(...) bb_error_msg(__VA_ARGS__)
-#define dbg_msg(...) ((void)0)
-
+#if 0
+# define dbg_msg(...) bb_error_msg(__VA_ARGS__)
+#else
+# define dbg_msg(...) ((void)0)
+#endif
 
 #ifdef TEST
 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
@@ -466,9 +468,18 @@ static char* FAST_FUNC process_stdin_with_replace(int n_max_chars, int n_max_arg
 
         while (1) {
                 int c = getchar();
+                if (p == buf) {
+                        if (c == EOF)
+                                goto ret; /* last line is empty, return "" */
+                        if (c == G.eol_ch)
+                                continue; /* empty line, ignore */
+                        /* Skip leading whitespace of each line: try
+                         * echo -e ' \t\v1 2 3 ' | xargs -I% echo '[%]'
+                         */
+                        if (ISSPACE(c))
+                                continue;
+                }
                 if (c == EOF || c == G.eol_ch) {
-                        if (p == buf)
-                                goto ret; /* empty line */
                         c = '\0';
                 }
                 *p++ = c;
diff --git a/testsuite/xargs.tests b/testsuite/xargs.tests
index 159f1ff69..e7c7c4b3d 100755
--- a/testsuite/xargs.tests
+++ b/testsuite/xargs.tests
@@ -61,4 +61,12 @@ testing "xargs -n2" \
 
 SKIP=
 
+optional FEATURE_XARGS_SUPPORT_QUOTES
+testing "xargs -I skips empty lines and leading whitespace" \
+        "xargs -I% echo '[%]'" \
+        "[2]\n[4]\n[6 6 ]\n[7]\n" \
+        "" " \n2\n\n4\n\n 6 6 \n \v \t 7\n\t\n\v\n"
+
+SKIP=
+
 exit $FAILCOUNT