textconv: refactor calls to run_textconv

This patch adds a fill_textconv wrapper, which centralizes
some minor logic like error checking and handling the case
of no-textconv.

In addition to dropping the number of lines, this will make
it easier in future patches to handle multiple types of
textconv.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff.c b/diff.c
index db2cd5d35f9de3e7ce74ae36a64f495c82dc836a..9665d6d41fbbe4d610a54c76655a58d251db0291 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -43,7 +43,8 @@ static char diff_colors[][COLOR_MAXLEN] = {
 };
 
 static void diff_filespec_load_driver(struct diff_filespec *one);
-static char *run_textconv(const char *, struct diff_filespec *, size_t *);
+static size_t fill_textconv(const char *cmd,
+                           struct diff_filespec *df, char **outbuf);
 
 static int parse_diff_color_slot(const char *var, int ofs)
 {
@@ -477,7 +478,7 @@ static void emit_rewrite_diff(const char *name_a,
        const char *reset = diff_get_color(color_diff, DIFF_RESET);
        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
        const char *a_prefix, *b_prefix;
-       const char *data_one, *data_two;
+       char *data_one, *data_two;
        size_t size_one, size_two;
        struct emit_callback ecbdata;
 
@@ -499,26 +500,8 @@ static void emit_rewrite_diff(const char *name_a,
        quote_two_c_style(&a_name, a_prefix, name_a, 0);
        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 
-       diff_populate_filespec(one, 0);
-       diff_populate_filespec(two, 0);
-       if (textconv_one) {
-               data_one = run_textconv(textconv_one, one, &size_one);
-               if (!data_one)
-                       die("unable to read files to diff");
-       }
-       else {
-               data_one = one->data;
-               size_one = one->size;
-       }
-       if (textconv_two) {
-               data_two = run_textconv(textconv_two, two, &size_two);
-               if (!data_two)
-                       die("unable to read files to diff");
-       }
-       else {
-               data_two = two->data;
-               size_two = two->size;
-       }
+       size_one = fill_textconv(textconv_one, one, &data_one);
+       size_two = fill_textconv(textconv_two, two, &data_two);
 
        memset(&ecbdata, 0, sizeof(ecbdata));
        ecbdata.color_diff = color_diff;
@@ -1717,20 +1700,8 @@ static void builtin_diff(const char *name_a,
                        strbuf_reset(&header);
                }
 
-               if (textconv_one) {
-                       size_t size;
-                       mf1.ptr = run_textconv(textconv_one, one, &size);
-                       if (!mf1.ptr)
-                               die("unable to read files to diff");
-                       mf1.size = size;
-               }
-               if (textconv_two) {
-                       size_t size;
-                       mf2.ptr = run_textconv(textconv_two, two, &size);
-                       if (!mf2.ptr)
-                               die("unable to read files to diff");
-                       mf2.size = size;
-               }
+               mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
+               mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
 
                pe = diff_funcname_pattern(one);
                if (!pe)
@@ -3916,3 +3887,26 @@ static char *run_textconv(const char *pgm, struct diff_filespec *spec,
 
        return strbuf_detach(&buf, outsize);
 }
+
+static size_t fill_textconv(const char *cmd,
+                           struct diff_filespec *df,
+                           char **outbuf)
+{
+       size_t size;
+
+       if (!cmd) {
+               if (!DIFF_FILE_VALID(df)) {
+                       *outbuf = "";
+                       return 0;
+               }
+               if (diff_populate_filespec(df, 0))
+                       die("unable to read files to diff");
+               *outbuf = df->data;
+               return df->size;
+       }
+
+       *outbuf = run_textconv(cmd, df, &size);
+       if (!*outbuf)
+               die("unable to read files to diff");
+       return size;
+}