Add LF-to-CRLF streaming conversion

If we do not have to guess or validate by scanning the input, we can
just stream this through.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/convert.c b/convert.c
index 4951372db821f02db512445602055c68a7c9309b..c352d66342a2e1f43e52f74582c62c5c3056e45b 100644 (file)
--- a/convert.c
+++ b/convert.c
@@ -872,6 +872,43 @@ int is_null_stream_filter(struct stream_filter *filter)
        return filter == &null_filter_singleton;
 }
 
+static int lf_to_crlf_filter_fn(struct stream_filter *filter,
+                               const char *input, size_t *isize_p,
+                               char *output, size_t *osize_p)
+{
+       size_t count;
+
+       if (!input)
+               return 0; /* we do not keep any states */
+       count = *isize_p;
+       if (count) {
+               size_t i, o;
+               for (i = o = 0; o < *osize_p && i < count; i++) {
+                       char ch = input[i];
+                       if (ch == '\n') {
+                               if (o + 1 < *osize_p)
+                                       output[o++] = '\r';
+                               else
+                                       break;
+                       }
+                       output[o++] = ch;
+               }
+
+               *osize_p -= o;
+               *isize_p -= i;
+       }
+       return 0;
+}
+
+static struct stream_filter_vtbl lf_to_crlf_vtbl = {
+       lf_to_crlf_filter_fn,
+       null_free_fn,
+};
+
+static struct stream_filter lf_to_crlf_filter_singleton = {
+       &lf_to_crlf_vtbl,
+};
+
 /*
  * Return an appropriately constructed filter for the path, or NULL if
  * the contents cannot be filtered without reading the whole thing
@@ -896,6 +933,10 @@ struct stream_filter *get_stream_filter(const char *path, const unsigned char *s
            (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE))
                return &null_filter_singleton;
 
+       if (output_eol(crlf_action) == EOL_CRLF &&
+           !(crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS))
+               return &lf_to_crlf_filter_singleton;
+
        return NULL;
 }