xdiff-interface: replace discard_hunk_line() with a flag

Remove the dummy discard_hunk_line() function added in
3b40a090fd4 (diff: avoid generating unused hunk header lines,
2018-11-02) in favor of having a new XDL_EMIT_NO_HUNK_HDR flag, for
use along with the two existing and similar XDL_EMIT_* flags.

Unlike the recently amended xdiff_emit_line_fn interface which'll be
called in a loop in xdl_emit_diff(), the hunk header is only emitted
once.

It makes more sense to pass this as a flag than provide a dummy
callback because that function may be able to skip doing certain work
if it knows the caller is doing nothing with the hunk header.

It would be possible to do so in the case of -U0 now, but the benefit
of doing so is so small that I haven't bothered. But this leaves the
door open to that, and more importantly makes the API use more
intuitive.

The reason we're putting a flag in the gap between 1<<0 and 1<<2 is
that the old 1<<1 flag was removed in 907681e940d (xdiff: drop
XDL_EMIT_COMMON, 2016-02-23) without re-ordering the remaining flags.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff.c b/diff.c
index 7a03c581c7938fd9fe2794af0775ae24707d8f58..fe3abac79feb46c255aafb25bab97aeaea583859 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -3725,7 +3725,8 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
                xpp.anchors_nr = o->anchors_nr;
                xecfg.ctxlen = o->context;
                xecfg.interhunkctxlen = o->interhunkcontext;
-               if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
+               xecfg.flags = XDL_EMIT_NO_HUNK_HDR;
+               if (xdi_diff_outf(&mf1, &mf2, NULL,
                                  diffstat_consume, diffstat, &xpp, &xecfg))
                        die("unable to generate diffstat for %s", one->path);
 
@@ -6233,8 +6234,8 @@ static int diff_get_patch_id(struct diff_options *options, struct object_id *oid
 
                xpp.flags = 0;
                xecfg.ctxlen = 3;
-               xecfg.flags = 0;
-               if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
+               xecfg.flags = XDL_EMIT_NO_HUNK_HDR;
+               if (xdi_diff_outf(&mf1, &mf2, NULL,
                                  patch_id_consume, &data, &xpp, &xecfg))
                        return error("unable to generate patch-id diff for %s",
                                     p->one->path);

diff --git a/diffcore-pickaxe.c b/diffcore-pickaxe.c
index 96183f4cfabaee9cfee29276d7067e86e36a662f..c88e50c632952afbf46eb859e93470fc207c54f0 100644 (file)
--- a/diffcore-pickaxe.c
+++ b/diffcore-pickaxe.c
@@ -53,6 +53,7 @@ static int diff_grep(mmfile_t *one, mmfile_t *two,
        memset(&xecfg, 0, sizeof(xecfg));
        ecbdata.regexp = regexp;
        ecbdata.hit = 0;
+       xecfg.flags = XDL_EMIT_NO_HUNK_HDR;
        xecfg.ctxlen = o->context;
        xecfg.interhunkctxlen = o->interhunkcontext;
 
@@ -60,7 +61,7 @@ static int diff_grep(mmfile_t *one, mmfile_t *two,
         * An xdiff error might be our "data->hit" from above. See the
         * comment for xdiff_emit_line_fn in xdiff-interface.h
         */
-       ret = xdi_diff_outf(one, two, discard_hunk_line, diffgrep_consume,
+       ret = xdi_diff_outf(one, two, NULL, diffgrep_consume,
                            &ecbdata, &xpp, &xecfg);
        if (ecbdata.hit)
                return 1;

diff --git a/xdiff-interface.c b/xdiff-interface.c
index 50c0ef759dd9e08acbc80e152555ed03609b8374..95f13a93ff9aef0833fb22faf87f791d2a1f49f9 100644 (file)
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -126,12 +126,6 @@ int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t co
        return xdl_diff(&a, &b, xpp, xecfg, xecb);
 }
 
-void discard_hunk_line(void *priv,
-                      long ob, long on, long nb, long nn,
-                      const char *func, long funclen)
-{
-}
-
 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
                  xdiff_emit_hunk_fn hunk_fn,
                  xdiff_emit_line_fn line_fn,

diff --git a/xdiff-interface.h b/xdiff-interface.h
index 3b6819586da6d9e93af0116cd7069532c26cccb2..4301a7eef274bb7796ad758d686f61b7c5b35395 100644 (file)
--- a/xdiff-interface.h
+++ b/xdiff-interface.h
@@ -53,14 +53,6 @@ void xdiff_clear_find_func(xdemitconf_t *xecfg);
 int git_xmerge_config(const char *var, const char *value, void *cb);
 extern int git_xmerge_style;
 
-/*
- * Can be used as a no-op hunk_fn for xdi_diff_outf(), since a NULL
- * one just sends the hunk line to the line_fn callback).
- */
-void discard_hunk_line(void *priv,
-                      long ob, long on, long nb, long nn,
-                      const char *func, long funclen);
-
 /*
  * Compare the strings l1 with l2 which are of size s1 and s2 respectively.
  * Returns 1 if the strings are deemed equal, 0 otherwise.

diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index 7a046051468f9e7e804d9eb7f0bd7eeeba6727db..b29deca5de84babed44bce2ff4934745c90ffc70 100644 (file)
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -50,6 +50,7 @@ extern "C" {
 
 /* xdemitconf_t.flags */
 #define XDL_EMIT_FUNCNAMES (1 << 0)
+#define XDL_EMIT_NO_HUNK_HDR (1 << 1)
 #define XDL_EMIT_FUNCCONTEXT (1 << 2)
 
 /* merge simplification levels */

diff --git a/xdiff/xemit.c b/xdiff/xemit.c
index 9d7d6c5087498a0a9079775cb3b744db69fe807e..1cbf2b9829e759dd20f5e714d1390b26fe8cdd3d 100644 (file)
--- a/xdiff/xemit.c
+++ b/xdiff/xemit.c
@@ -278,7 +278,8 @@ pre_context_calculation:
                                      s1 - 1, funclineprev);
                        funclineprev = s1 - 1;
                }
-               if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
+               if (!(xecfg->flags & XDL_EMIT_NO_HUNK_HDR) &&
+                   xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
                                      func_line.buf, func_line.len, ecb) < 0)
                        return -1;