blame: use xdi_diff_hunks(), get rid of struct patch

Based on a patch by Brian Downing, this replaces the struct patch based
code for blame passing with calls to xdi_diff_hunks().  This way we
avoid generating and then parsing patches; we only let the interesting
infos be passed to our callbacks instead.  This makes blame a bit faster:

   $ blame="./git blame -M -C -C -p --incremental v1.6.0"

   # master
   $ /usr/bin/time $blame Makefile >/dev/null
   1.38user 0.14system 0:01.52elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k
   0inputs+0outputs (0major+12226minor)pagefaults 0swaps
   $ /usr/bin/time $blame cache.h >/dev/null
   1.66user 0.13system 0:01.80elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
   0inputs+0outputs (0major+12262minor)pagefaults 0swaps

   # this patch series
   $ /usr/bin/time $blame Makefile >/dev/null
   1.27user 0.12system 0:01.40elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
   0inputs+0outputs (0major+11836minor)pagefaults 0swaps
   $ /usr/bin/time $blame cache.h >/dev/null
   1.52user 0.12system 0:01.70elapsed 97%CPU (0avgtext+0avgdata 0maxresident)k
   0inputs+0outputs (0major+12052minor)pagefaults 0swaps

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-blame.c b/builtin-blame.c
index 5ca7065171b4a531b6133f4ab1aa36392d72d0c3..b6bc5cf6a91a587d2fab979010e958f66b2db346 100644 (file)
--- a/builtin-blame.c
+++ b/builtin-blame.c
@@ -442,113 +442,6 @@ static struct origin *find_rename(struct scoreboard *sb,
        return porigin;
 }
 
-/*
- * Parsing of patch chunks...
- */
-struct chunk {
-       /* line number in postimage; up to but not including this
-        * line is the same as preimage
-        */
-       int same;
-
-       /* preimage line number after this chunk */
-       int p_next;
-
-       /* postimage line number after this chunk */
-       int t_next;
-};
-
-struct patch {
-       struct chunk *chunks;
-       int num;
-};
-
-struct blame_diff_state {
-       struct patch *ret;
-       unsigned hunk_post_context;
-       unsigned hunk_in_pre_context : 1;
-};
-
-static void process_u_diff(void *state_, char *line, unsigned long len)
-{
-       struct blame_diff_state *state = state_;
-       struct chunk *chunk;
-       int off1, off2, len1, len2, num;
-
-       num = state->ret->num;
-       if (len < 4 || line[0] != '@' || line[1] != '@') {
-               if (state->hunk_in_pre_context && line[0] == ' ')
-                       state->ret->chunks[num - 1].same++;
-               else {
-                       state->hunk_in_pre_context = 0;
-                       if (line[0] == ' ')
-                               state->hunk_post_context++;
-                       else
-                               state->hunk_post_context = 0;
-               }
-               return;
-       }
-
-       if (num && state->hunk_post_context) {
-               chunk = &state->ret->chunks[num - 1];
-               chunk->p_next -= state->hunk_post_context;
-               chunk->t_next -= state->hunk_post_context;
-       }
-       state->ret->num = ++num;
-       state->ret->chunks = xrealloc(state->ret->chunks,
-                                     sizeof(struct chunk) * num);
-       chunk = &state->ret->chunks[num - 1];
-       if (parse_hunk_header(line, len, &off1, &len1, &off2, &len2)) {
-               state->ret->num--;
-               return;
-       }
-
-       /* Line numbers in patch output are one based. */
-       off1--;
-       off2--;
-
-       chunk->same = len2 ? off2 : (off2 + 1);
-
-       chunk->p_next = off1 + (len1 ? len1 : 1);
-       chunk->t_next = chunk->same + len2;
-       state->hunk_in_pre_context = 1;
-       state->hunk_post_context = 0;
-}
-
-static struct patch *compare_buffer(mmfile_t *file_p, mmfile_t *file_o,
-                                   int context)
-{
-       struct blame_diff_state state;
-       xpparam_t xpp;
-       xdemitconf_t xecfg;
-       xdemitcb_t ecb;
-
-       memset(&xpp, 0, sizeof(xpp));
-       xpp.flags = xdl_opts;
-       memset(&xecfg, 0, sizeof(xecfg));
-       xecfg.ctxlen = context;
-       memset(&state, 0, sizeof(state));
-       state.ret = xmalloc(sizeof(struct patch));
-       state.ret->chunks = NULL;
-       state.ret->num = 0;
-
-       xdi_diff_outf(file_p, file_o, process_u_diff, &state, &xpp, &xecfg, &ecb);
-
-       if (state.ret->num) {
-               struct chunk *chunk;
-               chunk = &state.ret->chunks[state.ret->num - 1];
-               chunk->p_next -= state.hunk_post_context;
-               chunk->t_next -= state.hunk_post_context;
-       }
-       return state.ret;
-}
-
-static void free_patch(struct patch *p)
-{
-       free(p->chunks);
-       free(p);
-}
-
 /*
  * Link in a new blame entry to the scoreboard.  Entries that cover the
  * same line range have been removed from the scoreboard previously.
@@ -795,6 +688,22 @@ static void blame_chunk(struct scoreboard *sb,
        }
 }
 
+struct blame_chunk_cb_data {
+       struct scoreboard *sb;
+       struct origin *target;
+       struct origin *parent;
+       long plno;
+       long tlno;
+};
+
+static void blame_chunk_cb(void *data, long same, long p_next, long t_next)
+{
+       struct blame_chunk_cb_data *d = data;
+       blame_chunk(d->sb, d->tlno, d->plno, same, d->target, d->parent);
+       d->plno = p_next;
+       d->tlno = t_next;
+}
+
 /*
  * We are looking at the origin 'target' and aiming to pass blame
  * for the lines it is suspected to its parent.  Run diff to find
@@ -804,36 +713,28 @@ static int pass_blame_to_parent(struct scoreboard *sb,
                                struct origin *target,
                                struct origin *parent)
 {
-       int i, last_in_target, plno, tlno;
-       struct patch *patch;
+       int last_in_target;
        mmfile_t file_p, file_o;
+       struct blame_chunk_cb_data d = { sb, target, parent, 0, 0 };
+       xpparam_t xpp;
+       xdemitconf_t xecfg;
 
        last_in_target = find_last_in_target(sb, target);
        if (last_in_target < 0)
                return 1; /* nothing remains for this target */
 
-       /*
-        * Run diff between two origins and grab the patch output, so that
-        * we can pass blame for lines origin is currently suspected for
-        * to its parent.
-        */
        fill_origin_blob(parent, &file_p);
        fill_origin_blob(target, &file_o);
-       patch = compare_buffer(&file_p, &file_o, 0);
        num_get_patch++;
 
-       plno = tlno = 0;
-       for (i = 0; i < patch->num; i++) {
-               struct chunk *chunk = &patch->chunks[i];
-
-               blame_chunk(sb, tlno, plno, chunk->same, target, parent);
-               plno = chunk->p_next;
-               tlno = chunk->t_next;
-       }
+       memset(&xpp, 0, sizeof(xpp));
+       xpp.flags = xdl_opts;
+       memset(&xecfg, 0, sizeof(xecfg));
+       xecfg.ctxlen = 0;
+       xdi_diff_hunks(&file_p, &file_o, blame_chunk_cb, &d, &xpp, &xecfg);
        /* The rest (i.e. anything after tlno) are the same as the parent */
-       blame_chunk(sb, tlno, plno, last_in_target, target, parent);
+       blame_chunk(sb, d.tlno, d.plno, last_in_target, target, parent);
 
-       free_patch(patch);
        return 0;
 }
 
@@ -925,6 +826,23 @@ static void handle_split(struct scoreboard *sb,
        }
 }
 
+struct handle_split_cb_data {
+       struct scoreboard *sb;
+       struct blame_entry *ent;
+       struct origin *parent;
+       struct blame_entry *split;
+       long plno;
+       long tlno;
+};
+
+static void handle_split_cb(void *data, long same, long p_next, long t_next)
+{
+       struct handle_split_cb_data *d = data;
+       handle_split(d->sb, d->ent, d->tlno, d->plno, same, d->parent, d->split);
+       d->plno = p_next;
+       d->tlno = t_next;
+}
+
 /*
  * Find the lines from parent that are the same as ent so that
  * we can pass blames to it.  file_p has the blob contents for
@@ -939,8 +857,9 @@ static void find_copy_in_blob(struct scoreboard *sb,
        const char *cp;
        int cnt;
        mmfile_t file_o;
-       struct patch *patch;
-       int i, plno, tlno;
+       struct handle_split_cb_data d = { sb, ent, parent, split, 0, 0 };
+       xpparam_t xpp;
+       xdemitconf_t xecfg;
 
        /*
         * Prepare mmfile that contains only the lines in ent.
@@ -955,24 +874,18 @@ static void find_copy_in_blob(struct scoreboard *sb,
        }
        file_o.size = cp - file_o.ptr;
 
-       patch = compare_buffer(file_p, &file_o, 1);
-
        /*
         * file_o is a part of final image we are annotating.
         * file_p partially may match that image.
         */
+       memset(&xpp, 0, sizeof(xpp));
+       xpp.flags = xdl_opts;
+       memset(&xecfg, 0, sizeof(xecfg));
+       xecfg.ctxlen = 1;
        memset(split, 0, sizeof(struct blame_entry [3]));
-       plno = tlno = 0;
-       for (i = 0; i < patch->num; i++) {
-               struct chunk *chunk = &patch->chunks[i];
-
-               handle_split(sb, ent, tlno, plno, chunk->same, parent, split);
-               plno = chunk->p_next;
-               tlno = chunk->t_next;
-       }
+       xdi_diff_hunks(file_p, &file_o, handle_split_cb, &d, &xpp, &xecfg);
        /* remainder, if any, all match the preimage */
-       handle_split(sb, ent, tlno, plno, ent->num_lines, parent, split);
-       free_patch(patch);
+       handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
 }
 
 /*