Merge branch 'by/diff-graph'
authorJunio C Hamano <gitster@pobox.com>
Fri, 18 Jun 2010 18:16:57 +0000 (11:16 -0700)
committerJunio C Hamano <gitster@pobox.com>
Fri, 18 Jun 2010 18:16:57 +0000 (11:16 -0700)
* by/diff-graph:
Make --color-words work well with --graph
graph.c: register a callback for graph output
Emit a whole line in one go
diff.c: Output the text graph padding before each diff line
Output the graph columns at the end of the commit message
Add a prefix output callback to diff output

Conflicts:
diff.c

1  2 
diff.c
diff --combined diff.c
index b53b6ec8e2ced8c94c0353dddf07ca5c1dd79978,974b6a997a8ee506a0fec05e513374085c85aec6..c6b5fb376ac5ca165cb5441d2b17a6be5432f0f6
--- 1/diff.c
--- 2/diff.c
+++ b/diff.c
@@@ -30,7 -30,6 +30,7 @@@ static const char *diff_word_regex_cfg
  static const char *external_diff_cmd_cfg;
  int diff_auto_refresh_index = 1;
  static int diff_mnemonic_prefix;
 +static int diff_no_prefix;
  
  static char diff_colors[][COLOR_MAXLEN] = {
        GIT_COLOR_RESET,
@@@ -102,10 -101,6 +102,10 @@@ int git_diff_ui_config(const char *var
                diff_mnemonic_prefix = git_config_bool(var, value);
                return 0;
        }
 +      if (!strcmp(var, "diff.noprefix")) {
 +              diff_no_prefix = git_config_bool(var, value);
 +              return 0;
 +      }
        if (!strcmp(var, "diff.external"))
                return git_config_string(&external_diff_cmd_cfg, var, value);
        if (!strcmp(var, "diff.wordregex"))
@@@ -199,8 -194,8 +199,8 @@@ struct emit_callback 
        sane_truncate_fn truncate;
        const char **label_path;
        struct diff_words_data *diff_words;
+       struct diff_options *opt;
        int *found_changesp;
-       FILE *file;
        struct strbuf *header;
  };
  
@@@ -287,11 -282,19 +287,19 @@@ static void check_blank_at_eof(mmfile_
        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
  }
  
- static void emit_line_0(FILE *file, const char *set, const char *reset,
+ static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
                        int first, const char *line, int len)
  {
        int has_trailing_newline, has_trailing_carriage_return;
        int nofirst;
+       FILE *file = o->file;
+       if (o->output_prefix) {
+               struct strbuf *msg = NULL;
+               msg = o->output_prefix(o, o->output_prefix_data);
+               assert(msg);
+               fwrite(msg->buf, msg->len, 1, file);
+       }
  
        if (len == 0) {
                has_trailing_newline = (first == '\n');
                fputc('\n', file);
  }
  
- static void emit_line(FILE *file, const char *set, const char *reset,
+ static void emit_line(struct diff_options *o, const char *set, const char *reset,
                      const char *line, int len)
  {
-       emit_line_0(file, set, reset, line[0], line+1, len-1);
+       emit_line_0(o, set, reset, line[0], line+1, len-1);
  }
  
  static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
@@@ -346,15 -349,15 +354,15 @@@ static void emit_add_line(const char *r
        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
  
        if (!*ws)
-               emit_line_0(ecbdata->file, set, reset, '+', line, len);
+               emit_line_0(ecbdata->opt, set, reset, '+', line, len);
        else if (new_blank_line_at_eof(ecbdata, line, len))
                /* Blank line at EOF - paint '+' as well */
-               emit_line_0(ecbdata->file, ws, reset, '+', line, len);
+               emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
        else {
                /* Emit just the prefix, then the rest. */
-               emit_line_0(ecbdata->file, set, reset, '+', "", 0);
+               emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
                ws_check_emit(line, len, ecbdata->ws_rule,
-                             ecbdata->file, set, reset, ws);
+                             ecbdata->opt->file, set, reset, ws);
        }
  }
  
@@@ -367,6 -370,9 +375,9 @@@ static void emit_hunk_header(struct emi
        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
        static const char atat[2] = { '@', '@' };
        const char *cp, *ep;
+       struct strbuf msgbuf = STRBUF_INIT;
+       int org_len = len;
+       int i = 1;
  
        /*
         * As a hunk header must begin with "@@ -<old>, +<new> @@",
        if (len < 10 ||
            memcmp(line, atat, 2) ||
            !(ep = memmem(line + 2, len - 2, atat, 2))) {
-               emit_line(ecbdata->file, plain, reset, line, len);
+               emit_line(ecbdata->opt, plain, reset, line, len);
                return;
        }
        ep += 2; /* skip over @@ */
  
        /* The hunk header in fraginfo color */
-       emit_line(ecbdata->file, frag, reset, line, ep - line);
+       strbuf_add(&msgbuf, frag, strlen(frag));
+       strbuf_add(&msgbuf, line, ep - line);
+       strbuf_add(&msgbuf, reset, strlen(reset));
+       /*
+        * trailing "\r\n"
+        */
+       for ( ; i < 3; i++)
+               if (line[len - i] == '\r' || line[len - i] == '\n')
+                       len--;
  
        /* blank before the func header */
        for (cp = ep; ep - line < len; ep++)
                if (*ep != ' ' && *ep != '\t')
                        break;
-       if (ep != cp)
-               emit_line(ecbdata->file, plain, reset, cp, ep - cp);
+       if (ep != cp) {
+               strbuf_add(&msgbuf, plain, strlen(plain));
+               strbuf_add(&msgbuf, cp, ep - cp);
+               strbuf_add(&msgbuf, reset, strlen(reset));
+       }
+       if (ep < line + len) {
+               strbuf_add(&msgbuf, func, strlen(func));
+               strbuf_add(&msgbuf, ep, line + len - ep);
+               strbuf_add(&msgbuf, reset, strlen(reset));
+       }
  
-       if (ep < line + len)
-               emit_line(ecbdata->file, func, reset, ep, line + len - ep);
+       strbuf_add(&msgbuf, line + len, org_len - len);
+       emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
+       strbuf_release(&msgbuf);
  }
  
  static struct diff_tempfile *claim_diff_tempfile(void) {
@@@ -451,7 -476,7 +481,7 @@@ static void emit_rewrite_lines(struct e
                len = endp ? (endp - data + 1) : size;
                if (prefix != '+') {
                        ecb->lno_in_preimage++;
-                       emit_line_0(ecb->file, old, reset, '-',
+                       emit_line_0(ecb->opt, old, reset, '-',
                                    data, len);
                } else {
                        ecb->lno_in_postimage++;
        if (!endp) {
                const char *plain = diff_get_color(ecb->color_diff,
                                                   DIFF_PLAIN);
-               emit_line_0(ecb->file, plain, reset, '\\',
+               emit_line_0(ecb->opt, plain, reset, '\\',
                            nneof, strlen(nneof));
        }
  }
@@@ -487,6 -512,13 +517,13 @@@ static void emit_rewrite_diff(const cha
        char *data_one, *data_two;
        size_t size_one, size_two;
        struct emit_callback ecbdata;
+       char *line_prefix = "";
+       struct strbuf *msgbuf;
+       if (o && o->output_prefix) {
+               msgbuf = o->output_prefix(o, o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
  
        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
                a_prefix = o->b_prefix;
        ecbdata.color_diff = color_diff;
        ecbdata.found_changesp = &o->found_changes;
        ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
-       ecbdata.file = o->file;
+       ecbdata.opt = o;
        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
                mmfile_t mf1, mf2;
                mf1.ptr = (char *)data_one;
        lc_a = count_lines(data_one, size_one);
        lc_b = count_lines(data_two, size_two);
        fprintf(o->file,
-               "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
-               metainfo, a_name.buf, name_a_tab, reset,
-               metainfo, b_name.buf, name_b_tab, reset, fraginfo);
+               "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
+               line_prefix, metainfo, a_name.buf, name_a_tab, reset,
+               line_prefix, metainfo, b_name.buf, name_b_tab, reset,
+               line_prefix, fraginfo);
        print_line_count(o->file, lc_a);
        fprintf(o->file, " +");
        print_line_count(o->file, lc_b);
@@@ -589,7 -622,8 +627,8 @@@ struct diff_words_style diff_words_styl
  struct diff_words_data {
        struct diff_words_buffer minus, plus;
        const char *current_plus;
-       FILE *file;
+       int last_minus;
+       struct diff_options *opt;
        regex_t *word_regex;
        enum diff_words_type type;
        struct diff_words_style *style;
  static int fn_out_diff_words_write_helper(FILE *fp,
                                          struct diff_words_style_elem *st_el,
                                          const char *newline,
-                                         size_t count, const char *buf)
+                                         size_t count, const char *buf,
+                                         const char *line_prefix)
  {
+       int print = 0;
        while (count) {
                char *p = memchr(buf, '\n', count);
+               if (print)
+                       fputs(line_prefix, fp);
                if (p != buf) {
                        if (st_el->color && fputs(st_el->color, fp) < 0)
                                return -1;
                        return -1;
                count -= p + 1 - buf;
                buf = p + 1;
+               print = 1;
        }
        return 0;
  }
  
+ /*
+  * '--color-words' algorithm can be described as:
+  *
+  *   1. collect a the minus/plus lines of a diff hunk, divided into
+  *      minus-lines and plus-lines;
+  *
+  *   2. break both minus-lines and plus-lines into words and
+  *      place them into two mmfile_t with one word for each line;
+  *
+  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
+  *
+  * And for the common parts of the both file, we output the plus side text.
+  * diff_words->current_plus is used to trace the current position of the plus file
+  * which printed. diff_words->last_minus is used to trace the last minus word
+  * printed.
+  *
+  * For '--graph' to work with '--color-words', we need to output the graph prefix
+  * on each line of color words output. Generally, there are two conditions on
+  * which we should output the prefix.
+  *
+  *   1. diff_words->last_minus == 0 &&
+  *      diff_words->current_plus == diff_words->plus.text.ptr
+  *
+  *      that is: the plus text must start as a new line, and if there is no minus
+  *      word printed, a graph prefix must be printed.
+  *
+  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
+  *      *(diff_words->current_plus - 1) == '\n'
+  *
+  *      that is: a graph prefix must be printed following a '\n'
+  */
+ static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
+ {
+       if ((diff_words->last_minus == 0 &&
+               diff_words->current_plus == diff_words->plus.text.ptr) ||
+               (diff_words->current_plus > diff_words->plus.text.ptr &&
+               *(diff_words->current_plus - 1) == '\n')) {
+               return 1;
+       } else {
+               return 0;
+       }
+ }
  static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
  {
        struct diff_words_data *diff_words = priv;
        struct diff_words_style *style = diff_words->style;
        int minus_first, minus_len, plus_first, plus_len;
        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
+       struct diff_options *opt = diff_words->opt;
+       struct strbuf *msgbuf;
+       char *line_prefix = "";
  
        if (line[0] != '@' || parse_hunk_header(line, len,
                        &minus_first, &minus_len, &plus_first, &plus_len))
                return;
  
+       assert(opt);
+       if (opt->output_prefix) {
+               msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
        /* POSIX requires that first be decremented by one if len == 0... */
        if (minus_len) {
                minus_begin = diff_words->minus.orig[minus_first].begin;
        } else
                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
  
-       if (diff_words->current_plus != plus_begin)
-               fn_out_diff_words_write_helper(diff_words->file,
+       if (color_words_output_graph_prefix(diff_words)) {
+               fputs(line_prefix, diff_words->opt->file);
+       }
+       if (diff_words->current_plus != plus_begin) {
+               fn_out_diff_words_write_helper(diff_words->opt->file,
                                &style->ctx, style->newline,
                                plus_begin - diff_words->current_plus,
-                               diff_words->current_plus);
-       if (minus_begin != minus_end)
-               fn_out_diff_words_write_helper(diff_words->file,
+                               diff_words->current_plus, line_prefix);
+               if (*(plus_begin - 1) == '\n')
+                       fputs(line_prefix, diff_words->opt->file);
+       }
+       if (minus_begin != minus_end) {
+               fn_out_diff_words_write_helper(diff_words->opt->file,
                                &style->old, style->newline,
-                               minus_end - minus_begin, minus_begin);
-       if (plus_begin != plus_end)
-               fn_out_diff_words_write_helper(diff_words->file,
+                               minus_end - minus_begin, minus_begin,
+                               line_prefix);
+       }
+       if (plus_begin != plus_end) {
+               fn_out_diff_words_write_helper(diff_words->opt->file,
                                &style->new, style->newline,
-                               plus_end - plus_begin, plus_begin);
+                               plus_end - plus_begin, plus_begin,
+                               line_prefix);
+       }
  
        diff_words->current_plus = plus_end;
+       diff_words->last_minus = minus_first;
  }
  
  /* This function starts looking at *begin, and returns 0 iff a word was found. */
@@@ -744,22 -847,35 +852,35 @@@ static void diff_words_show(struct diff
        mmfile_t minus, plus;
        struct diff_words_style *style = diff_words->style;
  
+       struct diff_options *opt = diff_words->opt;
+       struct strbuf *msgbuf;
+       char *line_prefix = "";
+       assert(opt);
+       if (opt->output_prefix) {
+               msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
        /* special case: only removal */
        if (!diff_words->plus.text.size) {
-               fn_out_diff_words_write_helper(diff_words->file,
+               fputs(line_prefix, diff_words->opt->file);
+               fn_out_diff_words_write_helper(diff_words->opt->file,
                        &style->old, style->newline,
-                       diff_words->minus.text.size, diff_words->minus.text.ptr);
+                       diff_words->minus.text.size,
+                       diff_words->minus.text.ptr, line_prefix);
                diff_words->minus.text.size = 0;
                return;
        }
  
        diff_words->current_plus = diff_words->plus.text.ptr;
+       diff_words->last_minus = 0;
  
        memset(&xpp, 0, sizeof(xpp));
        memset(&xecfg, 0, sizeof(xecfg));
        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 -      xpp.flags = XDF_NEED_MINIMAL;
 +      xpp.flags = 0;
        /* as only the hunk header will be parsed, we need a 0-context */
        xecfg.ctxlen = 0;
        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
        free(minus.ptr);
        free(plus.ptr);
        if (diff_words->current_plus != diff_words->plus.text.ptr +
-                       diff_words->plus.text.size)
-               fn_out_diff_words_write_helper(diff_words->file,
+                       diff_words->plus.text.size) {
+               if (color_words_output_graph_prefix(diff_words))
+                       fputs(line_prefix, diff_words->opt->file);
+               fn_out_diff_words_write_helper(diff_words->opt->file,
                        &style->ctx, style->newline,
                        diff_words->plus.text.ptr + diff_words->plus.text.size
-                       - diff_words->current_plus, diff_words->current_plus);
+                       - diff_words->current_plus, diff_words->current_plus,
+                       line_prefix);
+       }
        diff_words->minus.text.size = diff_words->plus.text.size = 0;
  }
  
@@@ -843,9 -963,17 +968,17 @@@ static void fn_out_consume(void *priv, 
        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
+       struct diff_options *o = ecbdata->opt;
+       char *line_prefix = "";
+       struct strbuf *msgbuf;
+       if (o && o->output_prefix) {
+               msgbuf = o->output_prefix(o, o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
  
        if (ecbdata->header) {
-               fprintf(ecbdata->file, "%s", ecbdata->header->buf);
+               fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
                strbuf_reset(ecbdata->header);
                ecbdata->header = NULL;
        }
                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
  
-               fprintf(ecbdata->file, "%s--- %s%s%s\n",
-                       meta, ecbdata->label_path[0], reset, name_a_tab);
-               fprintf(ecbdata->file, "%s+++ %s%s%s\n",
-                       meta, ecbdata->label_path[1], reset, name_b_tab);
+               fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
+                       line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
+               fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
+                       line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
        }
  
                find_lno(line, ecbdata);
                emit_hunk_header(ecbdata, line, len);
                if (line[len-1] != '\n')
-                       putc('\n', ecbdata->file);
+                       putc('\n', ecbdata->opt->file);
                return;
        }
  
        if (len < 1) {
-               emit_line(ecbdata->file, reset, reset, line, len);
+               emit_line(ecbdata->opt, reset, reset, line, len);
                if (ecbdata->diff_words
                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
-                       fputs("~\n", ecbdata->file);
+                       fputs("~\n", ecbdata->opt->file);
                return;
        }
  
                }
                diff_words_flush(ecbdata);
                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
-                       emit_line(ecbdata->file, plain, reset, line, len);
-                       fputs("~\n", ecbdata->file);
+                       emit_line(ecbdata->opt, plain, reset, line, len);
+                       fputs("~\n", ecbdata->opt->file);
                } else {
                        /* don't print the prefix character */
-                       emit_line(ecbdata->file, plain, reset, line+1, len-1);
+                       emit_line(ecbdata->opt, plain, reset, line+1, len-1);
                }
                return;
        }
                ecbdata->lno_in_preimage++;
                if (line[0] == ' ')
                        ecbdata->lno_in_postimage++;
-               emit_line(ecbdata->file, color, reset, line, len);
+               emit_line(ecbdata->opt, color, reset, line, len);
        } else {
                ecbdata->lno_in_postimage++;
                emit_add_line(reset, ecbdata, line + 1, len - 1);
@@@ -1097,10 -1225,17 +1230,17 @@@ static void show_stats(struct diffstat_
        int total_files = data->nr;
        int width, name_width;
        const char *reset, *set, *add_c, *del_c;
+       const char *line_prefix = "";
+       struct strbuf *msg = NULL;
  
        if (data->nr == 0)
                return;
  
+       if (options->output_prefix) {
+               msg = options->output_prefix(options, options->output_prefix_data);
+               line_prefix = msg->buf;
+       }
        width = options->stat_width ? options->stat_width : 80;
        name_width = options->stat_name_width ? options->stat_name_width : 50;
  
                }
  
                if (data->files[i]->is_binary) {
+                       fprintf(options->file, "%s", line_prefix);
                        show_name(options->file, prefix, name, len);
                        fprintf(options->file, "  Bin ");
                        fprintf(options->file, "%s%"PRIuMAX"%s",
                        continue;
                }
                else if (data->files[i]->is_unmerged) {
+                       fprintf(options->file, "%s", line_prefix);
                        show_name(options->file, prefix, name, len);
                        fprintf(options->file, "  Unmerged\n");
                        continue;
                        add = scale_linear(add, width, max_change);
                        del = scale_linear(del, width, max_change);
                }
+               fprintf(options->file, "%s", line_prefix);
                show_name(options->file, prefix, name, len);
                fprintf(options->file, "%5"PRIuMAX"%s", added + deleted,
                                added + deleted ? " " : "");
                show_graph(options->file, '-', del, del_c, reset);
                fprintf(options->file, "\n");
        }
+       fprintf(options->file, "%s", line_prefix);
        fprintf(options->file,
               " %d files changed, %d insertions(+), %d deletions(-)\n",
               total_files, adds, dels);
@@@ -1237,6 -1376,12 +1381,12 @@@ static void show_shortstats(struct diff
                        }
                }
        }
+       if (options->output_prefix) {
+               struct strbuf *msg = NULL;
+               msg = options->output_prefix(options,
+                               options->output_prefix_data);
+               fprintf(options->file, "%s", msg->buf);
+       }
        fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
               total_files, adds, dels);
  }
@@@ -1251,6 -1396,13 +1401,13 @@@ static void show_numstat(struct diffsta
        for (i = 0; i < data->nr; i++) {
                struct diffstat_file *file = data->files[i];
  
+               if (options->output_prefix) {
+                       struct strbuf *msg = NULL;
+                       msg = options->output_prefix(options,
+                                       options->output_prefix_data);
+                       fprintf(options->file, "%s", msg->buf);
+               }
                if (file->is_binary)
                        fprintf(options->file, "-\t-\t");
                else
@@@ -1286,10 -1438,18 +1443,18 @@@ struct dirstat_dir 
        int alloc, nr, percent, cumulative;
  };
  
- static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
+ static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
+               unsigned long changed, const char *base, int baselen)
  {
        unsigned long this_dir = 0;
        unsigned int sources = 0;
+       const char *line_prefix = "";
+       struct strbuf *msg = NULL;
+       if (opt->output_prefix) {
+               msg = opt->output_prefix(opt, opt->output_prefix_data);
+               line_prefix = msg->buf;
+       }
  
        while (dir->nr) {
                struct dirstat_file *f = dir->files;
                slash = strchr(f->name + baselen, '/');
                if (slash) {
                        int newbaselen = slash + 1 - f->name;
-                       this = gather_dirstat(file, dir, changed, f->name, newbaselen);
+                       this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
                        sources++;
                } else {
                        this = f->changed;
                if (permille) {
                        int percent = permille / 10;
                        if (percent >= dir->percent) {
-                               fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
+                               fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
+                                       percent, permille % 10, baselen, base);
                                if (!dir->cumulative)
                                        return 0;
                        }
@@@ -1406,7 -1567,7 +1572,7 @@@ static void show_dirstat(struct diff_op
  
        /* Show all directories with more than x% of the changes */
        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
-       gather_dirstat(options->file, &dir, changed, "", 0);
+       gather_dirstat(options, &dir, changed, "", 0);
  }
  
  static void free_diffstat_info(struct diffstat_t *diffstat)
@@@ -1464,6 -1625,15 +1630,15 @@@ static void checkdiff_consume(void *pri
        const char *reset = diff_get_color(color_diff, DIFF_RESET);
        const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
        char *err;
+       char *line_prefix = "";
+       struct strbuf *msgbuf;
+       assert(data->o);
+       if (data->o->output_prefix) {
+               msgbuf = data->o->output_prefix(data->o,
+                       data->o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
  
        if (line[0] == '+') {
                unsigned bad;
                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
                        data->status |= 1;
                        fprintf(data->o->file,
-                               "%s:%d: leftover conflict marker\n",
-                               data->filename, data->lineno);
+                               "%s%s:%d: leftover conflict marker\n",
+                               line_prefix, data->filename, data->lineno);
                }
                bad = ws_check(line + 1, len - 1, data->ws_rule);
                if (!bad)
                        return;
                data->status |= bad;
                err = whitespace_error_string(bad);
-               fprintf(data->o->file, "%s:%d: %s.\n",
-                       data->filename, data->lineno, err);
+               fprintf(data->o->file, "%s%s:%d: %s.\n",
+                       line_prefix, data->filename, data->lineno, err);
                free(err);
-               emit_line(data->o->file, set, reset, line, 1);
+               emit_line(data->o, set, reset, line, 1);
                ws_check_emit(line + 1, len - 1, data->ws_rule,
                              data->o->file, set, reset, ws);
        } else if (line[0] == ' ') {
@@@ -1520,7 -1690,7 +1695,7 @@@ static unsigned char *deflate_it(char *
        return deflated;
  }
  
- static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
+ static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
  {
        void *cp;
        void *delta;
        }
  
        if (delta && delta_size < deflate_size) {
-               fprintf(file, "delta %lu\n", orig_size);
+               fprintf(file, "%sdelta %lu\n", prefix, orig_size);
                free(deflated);
                data = delta;
                data_size = delta_size;
        }
        else {
-               fprintf(file, "literal %lu\n", two->size);
+               fprintf(file, "%sliteral %lu\n", prefix, two->size);
                free(delta);
                data = deflated;
                data_size = deflate_size;
                        line[0] = bytes - 26 + 'a' - 1;
                encode_85(line + 1, cp, bytes);
                cp = (char *) cp + bytes;
+               fprintf(file, "%s", prefix);
                fputs(line, file);
                fputc('\n', file);
        }
-       fprintf(file, "\n");
+       fprintf(file, "%s\n", prefix);
        free(data);
  }
  
- static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
+ static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
  {
-       fprintf(file, "GIT binary patch\n");
-       emit_binary_diff_body(file, one, two);
-       emit_binary_diff_body(file, two, one);
+       fprintf(file, "%sGIT binary patch\n", prefix);
+       emit_binary_diff_body(file, one, two, prefix);
+       emit_binary_diff_body(file, two, one, prefix);
  }
  
  static void diff_filespec_load_driver(struct diff_filespec *one)
@@@ -1673,6 -1844,13 +1849,13 @@@ static void builtin_diff(const char *na
        struct userdiff_driver *textconv_one = NULL;
        struct userdiff_driver *textconv_two = NULL;
        struct strbuf header = STRBUF_INIT;
+       struct strbuf *msgbuf;
+       char *line_prefix = "";
+       if (o->output_prefix) {
+               msgbuf = o->output_prefix(o, o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
  
        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
                        (!one->mode || S_ISGITLINK(one->mode)) &&
        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
-       strbuf_addf(&header, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
+       strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, set, a_one, b_two, reset);
        if (lbl[0][0] == '/') {
                /* /dev/null */
-               strbuf_addf(&header, "%snew file mode %06o%s\n", set, two->mode, reset);
+               strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, set, two->mode, reset);
 -              if (xfrm_msg && xfrm_msg[0])
 -                      strbuf_addf(&header, "%s%s%s\n", set, xfrm_msg, reset);
 +              if (xfrm_msg)
 +                      strbuf_addstr(&header, xfrm_msg);
        }
        else if (lbl[1][0] == '/') {
-               strbuf_addf(&header, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
+               strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, set, one->mode, reset);
 -              if (xfrm_msg && xfrm_msg[0])
 -                      strbuf_addf(&header, "%s%s%s\n", set, xfrm_msg, reset);
 +              if (xfrm_msg)
 +                      strbuf_addstr(&header, xfrm_msg);
        }
        else {
                if (one->mode != two->mode) {
-                       strbuf_addf(&header, "%sold mode %06o%s\n", set, one->mode, reset);
-                       strbuf_addf(&header, "%snew mode %06o%s\n", set, two->mode, reset);
+                       strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, set, one->mode, reset);
+                       strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, set, two->mode, reset);
                }
 -              if (xfrm_msg && xfrm_msg[0])
 -                      strbuf_addf(&header, "%s%s%s\n", set, xfrm_msg, reset);
 +              if (xfrm_msg)
 +                      strbuf_addstr(&header, xfrm_msg);
  
                /*
                 * we do not run diff between different kind
                fprintf(o->file, "%s", header.buf);
                strbuf_reset(&header);
                if (DIFF_OPT_TST(o, BINARY))
-                       emit_binary_diff(o->file, &mf1, &mf2);
+                       emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
                else
-                       fprintf(o->file, "Binary files %s and %s differ\n",
-                               lbl[0], lbl[1]);
+                       fprintf(o->file, "%sBinary files %s and %s differ\n",
+                               line_prefix, lbl[0], lbl[1]);
                o->found_changes = 1;
        }
        else {
                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
-               ecbdata.file = o->file;
+               ecbdata.opt = o;
                ecbdata.header = header.len ? &header : NULL;
 -              xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 +              xpp.flags = o->xdl_opts;
                xecfg.ctxlen = o->context;
                xecfg.interhunkctxlen = o->interhunkcontext;
                xecfg.flags = XDL_EMIT_FUNCNAMES;
  
                        ecbdata.diff_words =
                                xcalloc(1, sizeof(struct diff_words_data));
-                       ecbdata.diff_words->file = o->file;
                        ecbdata.diff_words->type = o->word_diff;
+                       ecbdata.diff_words->opt = o;
                        if (!o->word_regex)
                                o->word_regex = userdiff_word_regex(one);
                        if (!o->word_regex)
@@@ -1899,7 -2077,7 +2082,7 @@@ static void builtin_diffstat(const cha
  
                memset(&xpp, 0, sizeof(xpp));
                memset(&xecfg, 0, sizeof(xecfg));
 -              xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 +              xpp.flags = o->xdl_opts;
                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
                              &xpp, &xecfg);
        }
@@@ -1947,7 -2125,7 +2130,7 @@@ static void builtin_checkdiff(const cha
                memset(&xpp, 0, sizeof(xpp));
                memset(&xecfg, 0, sizeof(xecfg));
                xecfg.ctxlen = 1; /* at least one context line */
 -              xpp.flags = XDF_NEED_MINIMAL;
 +              xpp.flags = 0;
                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
                              &xpp, &xecfg);
  
@@@ -2384,36 -2562,38 +2567,47 @@@ static void fill_metainfo(struct strbu
                          struct diff_filespec *one,
                          struct diff_filespec *two,
                          struct diff_options *o,
 -                        struct diff_filepair *p)
 +                        struct diff_filepair *p,
 +                        int use_color)
  {
 +      const char *set = diff_get_color(use_color, DIFF_METAINFO);
 +      const char *reset = diff_get_color(use_color, DIFF_RESET);
+       struct strbuf *msgbuf;
+       char *line_prefix = "";
+       if (o->output_prefix) {
+               msgbuf = o->output_prefix(o, o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
  
        strbuf_init(msg, PATH_MAX * 2 + 300);
        switch (p->status) {
        case DIFF_STATUS_COPIED:
-               strbuf_addf(msg, "%ssimilarity index %d%%",
-                           set, similarity_index(p));
-               strbuf_addf(msg, "%s\n%scopy from ", reset, set);
 -              strbuf_addf(msg, "%ssimilarity index %d%%", line_prefix, similarity_index(p));
 -              strbuf_addf(msg, "\n%scopy from ", line_prefix);
++              strbuf_addf(msg, "%s%ssimilarity index %d%%",
++                          line_prefix, set, similarity_index(p));
++              strbuf_addf(msg, "%s\n%s%scopy from ",
++                          reset,  line_prefix, set);
                quote_c_style(name, msg, NULL, 0);
-               strbuf_addf(msg, "%s\n%scopy to ", reset, set);
 -              strbuf_addf(msg, "\n%scopy to ", line_prefix);
++              strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
                quote_c_style(other, msg, NULL, 0);
 -              strbuf_addch(msg, '\n');
 +              strbuf_addf(msg, "%s\n", reset);
                break;
        case DIFF_STATUS_RENAMED:
-               strbuf_addf(msg, "%ssimilarity index %d%%",
-                           set, similarity_index(p));
-               strbuf_addf(msg, "%s\n%srename from ", reset, set);
 -              strbuf_addf(msg, "%ssimilarity index %d%%", line_prefix, similarity_index(p));
 -              strbuf_addf(msg, "\n%srename from ", line_prefix);
++              strbuf_addf(msg, "%s%ssimilarity index %d%%",
++                          line_prefix, set, similarity_index(p));
++              strbuf_addf(msg, "%s\n%s%srename from ",
++                          reset, line_prefix, set);
                quote_c_style(name, msg, NULL, 0);
-               strbuf_addf(msg, "%s\n%srename to ", reset, set);
 -              strbuf_addf(msg, "\n%srename to ", line_prefix);
++              strbuf_addf(msg, "%s\n%s%srename to ",
++                          reset, line_prefix, set);
                quote_c_style(other, msg, NULL, 0);
 -              strbuf_addch(msg, '\n');
 +              strbuf_addf(msg, "%s\n", reset);
                break;
        case DIFF_STATUS_MODIFIED:
                if (p->score) {
-                       strbuf_addf(msg, "%sdissimilarity index %d%%%s\n",
 -                      strbuf_addf(msg, "%sdissimilarity index %d%%\n",
 -                                  line_prefix, similarity_index(p));
++                      strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
++                                  line_prefix,
 +                                  set, similarity_index(p), reset);
                        break;
                }
                /* fallthru */
                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
                                abbrev = 40;
                }
-               strbuf_addf(msg, "%sindex %s..", set,
 -              strbuf_addf(msg, "%sindex %.*s..%.*s",
 -                          line_prefix, abbrev, sha1_to_hex(one->sha1),
 -                          abbrev, sha1_to_hex(two->sha1));
++              strbuf_addf(msg, "%s%sindex %s..", set,
++                          line_prefix,
 +                          find_unique_abbrev(one->sha1, abbrev));
 +              strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
                if (one->mode == two->mode)
                        strbuf_addf(msg, " %06o", one->mode);
 -              strbuf_addch(msg, '\n');
 +              strbuf_addf(msg, "%s\n", reset);
        }
 -      if (msg->len)
 -              strbuf_setlen(msg, msg->len - 1);
  }
  
  static void run_diff_cmd(const char *pgm,
        const char *xfrm_msg = NULL;
        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
  
 -      if (msg) {
 -              fill_metainfo(msg, name, other, one, two, o, p);
 -              xfrm_msg = msg->len ? msg->buf : NULL;
 -      }
 -
        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
                pgm = NULL;
        else {
                        pgm = drv->external;
        }
  
 +      if (msg) {
 +              /*
 +               * don't use colors when the header is intended for an
 +               * external diff driver
 +               */
 +              fill_metainfo(msg, name, other, one, two, o, p,
 +                            DIFF_OPT_TST(o, COLOR_DIFF) && !pgm);
 +              xfrm_msg = msg->len ? msg->buf : NULL;
 +      }
 +
        if (pgm) {
                run_external_diff(pgm, name, other, one, two, xfrm_msg,
                                  complete_rewrite);
@@@ -2630,9 -2807,7 +2825,9 @@@ void diff_setup(struct diff_options *op
                DIFF_OPT_SET(options, COLOR_DIFF);
        options->detect_rename = diff_detect_rename_default;
  
 -      if (!diff_mnemonic_prefix) {
 +      if (diff_no_prefix) {
 +              options->a_prefix = options->b_prefix = "";
 +      } else if (!diff_mnemonic_prefix) {
                options->a_prefix = "a/";
                options->b_prefix = "b/";
        }
@@@ -3140,6 -3315,11 +3335,11 @@@ static void diff_flush_raw(struct diff_
  {
        int line_termination = opt->line_termination;
        int inter_name_termination = line_termination ? '\t' : '\0';
+       if (opt->output_prefix) {
+               struct strbuf *msg = NULL;
+               msg = opt->output_prefix(opt, opt->output_prefix_data);
+               fprintf(opt->file, "%s", msg->buf);
+       }
  
        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
@@@ -3385,48 -3565,62 +3585,62 @@@ static void show_file_mode_name(FILE *f
  }
  
  
- static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
+ static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
+               const char *line_prefix)
  {
        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
-               fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
-                       show_name ? ' ' : '\n');
+               fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
+                       p->two->mode, show_name ? ' ' : '\n');
                if (show_name) {
                        write_name_quoted(p->two->path, file, '\n');
                }
        }
  }
  
- static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
+ static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
+                       const char *line_prefix)
  {
        char *names = pprint_rename(p->one->path, p->two->path);
  
        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
        free(names);
-       show_mode_change(file, p, 0);
+       show_mode_change(file, p, 0, line_prefix);
  }
  
- static void diff_summary(FILE *file, struct diff_filepair *p)
+ static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
  {
+       FILE *file = opt->file;
+       char *line_prefix = "";
+       if (opt->output_prefix) {
+               struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
+               line_prefix = buf->buf;
+       }
        switch(p->status) {
        case DIFF_STATUS_DELETED:
+               fputs(line_prefix, file);
                show_file_mode_name(file, "delete", p->one);
                break;
        case DIFF_STATUS_ADDED:
+               fputs(line_prefix, file);
                show_file_mode_name(file, "create", p->two);
                break;
        case DIFF_STATUS_COPIED:
-               show_rename_copy(file, "copy", p);
+               fputs(line_prefix, file);
+               show_rename_copy(file, "copy", p, line_prefix);
                break;
        case DIFF_STATUS_RENAMED:
-               show_rename_copy(file, "rename", p);
+               fputs(line_prefix, file);
+               show_rename_copy(file, "rename", p, line_prefix);
                break;
        default:
                if (p->score) {
-                       fputs(" rewrite ", file);
+                       fprintf(file, "%s rewrite ", line_prefix);
                        write_name_quoted(p->two->path, file, ' ');
                        fprintf(file, "(%d%%)\n", similarity_index(p));
                }
-               show_mode_change(file, p, !p->score);
+               show_mode_change(file, p, !p->score, line_prefix);
                break;
        }
  }
@@@ -3537,7 -3731,7 +3751,7 @@@ static int diff_get_patch_id(struct dif
                                        len2, p->two->path);
                git_SHA1_Update(&ctx, buffer, len1);
  
 -              xpp.flags = XDF_NEED_MINIMAL;
 +              xpp.flags = 0;
                xecfg.ctxlen = 3;
                xecfg.flags = XDL_EMIT_FUNCNAMES;
                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
@@@ -3635,8 -3829,9 +3849,9 @@@ void diff_flush(struct diff_options *op
                show_dirstat(options);
  
        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
-               for (i = 0; i < q->nr; i++)
-                       diff_summary(options->file, q->queue[i]);
+               for (i = 0; i < q->nr; i++) {
+                       diff_summary(options, q->queue[i]);
+               }
                separator++;
        }