diff: do not use null sha1 as a sentinel value

diff --git a/diff.c b/diff.c
index 84780fd5e641d9f1042f82863d1290f7ad8d92b5..8933dd19969124e33a6433aaa54d3ea54e573a33 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -1276,13 +1276,15 @@ const char mime_boundary_leader[] = "------------";
 
 static int scale_linear(int it, int width, int max_change)
 {
+       if (!it)
+               return 0;
        /*
-        * make sure that at least one '-' is printed if there were deletions,
-        * and likewise for '+'.
+        * make sure that at least one '-' or '+' is printed if
+        * there is any change to this path. The easiest way is to
+        * scale linearly as if the alloted width is one column shorter
+        * than it is, and then add 1 to the result.
         */
-       if (max_change < 2)
-               return it;
-       return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
+       return 1 + (it * (width - 1) / max_change);
 }
 
 static void show_name(FILE *file,
@@ -1498,8 +1500,19 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
                dels += del;
 
                if (width <= max_change) {
-                       add = scale_linear(add, width, max_change);
-                       del = scale_linear(del, width, max_change);
+                       int total = add + del;
+
+                       total = scale_linear(add + del, width, max_change);
+                       if (total < 2 && add && del)
+                               /* width >= 2 due to the sanity check */
+                               total = 2;
+                       if (add < del) {
+                               add = scale_linear(add, width, max_change);
+                               del = total - add;
+                       } else {
+                               del = scale_linear(del, width, max_change);
+                               add = total - del;
+                       }
                }
                fprintf(options->file, "%s", line_prefix);
                show_name(options->file, prefix, name, len);
@@ -2197,7 +2210,7 @@ static void builtin_diff(const char *name_a,
                struct emit_callback ecbdata;
                const struct userdiff_funcname *pe;
 
-               if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS) || must_show_header) {
+               if (must_show_header) {
                        fprintf(o->file, "%s", header.buf);
                        strbuf_reset(&header);
                }
@@ -2430,12 +2443,12 @@ void free_filespec(struct diff_filespec *spec)
 }
 
 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
-                  unsigned short mode)
+                  int sha1_valid, unsigned short mode)
 {
        if (mode) {
                spec->mode = canon_mode(mode);
                hashcpy(spec->sha1, sha1);
-               spec->sha1_valid = !is_null_sha1(sha1);
+               spec->sha1_valid = sha1_valid;
        }
 }
 
@@ -4576,6 +4589,7 @@ static int is_submodule_ignored(const char *path, struct diff_options *options)
 void diff_addremove(struct diff_options *options,
                    int addremove, unsigned mode,
                    const unsigned char *sha1,
+                   int sha1_valid,
                    const char *concatpath, unsigned dirty_submodule)
 {
        struct diff_filespec *one, *two;
@@ -4607,9 +4621,9 @@ void diff_addremove(struct diff_options *options,
        two = alloc_filespec(concatpath);
 
        if (addremove != '+')
-               fill_filespec(one, sha1, mode);
+               fill_filespec(one, sha1, sha1_valid, mode);
        if (addremove != '-') {
-               fill_filespec(two, sha1, mode);
+               fill_filespec(two, sha1, sha1_valid, mode);
                two->dirty_submodule = dirty_submodule;
        }
 
@@ -4622,6 +4636,7 @@ void diff_change(struct diff_options *options,
                 unsigned old_mode, unsigned new_mode,
                 const unsigned char *old_sha1,
                 const unsigned char *new_sha1,
+                int old_sha1_valid, int new_sha1_valid,
                 const char *concatpath,
                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
 {
@@ -4636,6 +4651,8 @@ void diff_change(struct diff_options *options,
                const unsigned char *tmp_c;
                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
+               tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
+                       new_sha1_valid = tmp;
                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
                        new_dirty_submodule = tmp;
        }
@@ -4646,8 +4663,8 @@ void diff_change(struct diff_options *options,
 
        one = alloc_filespec(concatpath);
        two = alloc_filespec(concatpath);
-       fill_filespec(one, old_sha1, old_mode);
-       fill_filespec(two, new_sha1, new_mode);
+       fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
+       fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
        one->dirty_submodule = old_dirty_submodule;
        two->dirty_submodule = new_dirty_submodule;