[PATCH V2/RFC][GSoC] diff-no-index: transform "$directory $file" args to "$directory/$file $file"

[Yurii Shevtsov <ungetch@xxxxxxxxx>]

git diff --no-index refuses to compare if args are directory and file,
instead of usual diff.

Now git diff --no-index modifies args, if they're directory and file,
and diffs files, as usual diff does.

Changes are done in diff_no_index().

Helped-by: Junio C Hamano <gitster@xxxxxxxxx>
Signed-off-by: Yurii Shevtsov <ungetch@xxxxxxxxx>
---
 diff-no-index.c |   31 +++++++++++++++++++++++++++++--
 1 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/diff-no-index.c b/diff-no-index.c
index 265709b..ecff15e 100644
--- a/diff-no-index.c
+++ b/diff-no-index.c
@@ -186,7 +186,7 @@ void diff_no_index(struct rev_info *revs,
            int argc, const char **argv,
            const char *prefix)
 {
-    int i, prefixlen;
+    int i, prefixlen, mode1 = 0, mode2 = 0;
     const char *paths[2];

     diff_setup(&revs->diffopt);
@@ -229,8 +229,35 @@ void diff_no_index(struct rev_info *revs,
     setup_diff_pager(&revs->diffopt);
     DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);

-    if (queue_diff(&revs->diffopt, paths[0], paths[1]))
+    if (get_mode(paths[0], &mode1) || get_mode(paths[1], &mode2))
+        exit(2);
+
+    if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2)) {
+        struct strbuf pathtofile;
+        const char *dir, *file;
+        char *filename;
+        int ret;
+
+        dir = S_ISDIR(mode1) ? paths[0] : paths[1];
+        file = (dir == paths[0]) ? paths[1] : paths[0];
+        strbuf_init(&pathtofile, strlen(paths[0]) + strlen(paths[1]) + 1);
+        strbuf_addstr(&pathtofile, dir);
+        if (pathtofile.len && pathtofile.buf[pathtofile.len - 1] != '/')
+               strbuf_addch(&pathtofile, '/');
+        filename = strrchr(file, '/');
+        strbuf_addstr(&pathtofile, filename ? (filename + 1) : file);
+
+        if (file == paths[0])
+            ret = queue_diff(&revs->diffopt, file, pathtofile.buf);
+        else
+            ret = queue_diff(&revs->diffopt, pathtofile.buf, file);
+        strbuf_release(&pathtofile);
+        if (ret)
+            exit(1);
+    }
+    else if (queue_diff(&revs->diffopt, paths[0], paths[1]))
         exit(1);
+
     diff_set_mnemonic_prefix(&revs->diffopt, "1/", "2/");
     diffcore_std(&revs->diffopt);
     diff_flush(&revs->diffopt);
-- 

Attached patch file because gmail always replaces tabs with spaces and
refuses to authorize 'git send-email'

Attachment: 0001-git-diff-no-index-refuses-to-compare-if-args-are-dir.patch
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