compat: Add simplified merge sort implementation from glibc
[gitweb.git] / diff.c
diff --git a/diff.c b/diff.c
index b08d28a5780cf242a4de78e0f5c4007b7041f392..5b8afdcb05abd4f634b49adb2f521fc75e220647 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -10,6 +10,7 @@
 #include "color.h"
 #include "attr.h"
 #include "run-command.h"
+#include "utf8.h"
 
 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
@@ -20,6 +21,7 @@
 static int diff_detect_rename_default;
 static int diff_rename_limit_default = 100;
 static int diff_use_color_default;
+static const char *external_diff_cmd_cfg;
 int diff_auto_refresh_index = 1;
 
 static char diff_colors[][COLOR_MAXLEN] = {
@@ -58,14 +60,6 @@ static struct ll_diff_driver {
        char *cmd;
 } *user_diff, **user_diff_tail;
 
-static void read_config_if_needed(void)
-{
-       if (!user_diff_tail) {
-               user_diff_tail = &user_diff;
-               git_config(git_diff_ui_config);
-       }
-}
-
 /*
  * Currently there is only "diff.<drivername>.command" variable;
  * because there are "diff.color.<slot>" variables, we are parsing
@@ -146,7 +140,7 @@ int git_diff_ui_config(const char *var, const char *value)
                return 0;
        }
        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
-               diff_use_color_default = git_config_colorbool(var, value);
+               diff_use_color_default = git_config_colorbool(var, value, -1);
                return 0;
        }
        if (!strcmp(var, "diff.renames")) {
@@ -163,22 +157,38 @@ int git_diff_ui_config(const char *var, const char *value)
                diff_auto_refresh_index = git_config_bool(var, value);
                return 0;
        }
+       if (!strcmp(var, "diff.external")) {
+               external_diff_cmd_cfg = xstrdup(value);
+               return 0;
+       }
        if (!prefixcmp(var, "diff.")) {
                const char *ep = strrchr(var, '.');
 
                if (ep != var + 4) {
                        if (!strcmp(ep, ".command"))
                                return parse_lldiff_command(var, ep, value);
-                       if (!strcmp(ep, ".funcname"))
-                               return parse_funcname_pattern(var, ep, value);
                }
        }
+
+       return git_diff_basic_config(var, value);
+}
+
+int git_diff_basic_config(const char *var, const char *value)
+{
        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
                int slot = parse_diff_color_slot(var, 11);
                color_parse(value, var, diff_colors[slot]);
                return 0;
        }
 
+       if (!prefixcmp(var, "diff.")) {
+               const char *ep = strrchr(var, '.');
+               if (ep != var + 4) {
+                       if (!strcmp(ep, ".funcname"))
+                               return parse_funcname_pattern(var, ep, value);
+               }
+       }
+
        return git_default_config(var, value);
 }
 
@@ -209,6 +219,8 @@ static const char *external_diff(void)
        if (done_preparing)
                return external_diff_cmd;
        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
+       if (!external_diff_cmd)
+               external_diff_cmd = external_diff_cmd_cfg;
        done_preparing = 1;
        return external_diff_cmd;
 }
@@ -283,28 +295,35 @@ static void emit_rewrite_diff(const char *name_a,
                              const char *name_b,
                              struct diff_filespec *one,
                              struct diff_filespec *two,
-                             int color_diff)
+                             struct diff_options *o)
 {
        int lc_a, lc_b;
+       int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
        const char *name_a_tab, *name_b_tab;
        const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
        const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
        const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
        const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
        const char *reset = diff_get_color(color_diff, DIFF_RESET);
+       static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 
        name_a += (*name_a == '/');
        name_b += (*name_b == '/');
        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 
+       strbuf_reset(&a_name);
+       strbuf_reset(&b_name);
+       quote_two_c_style(&a_name, o->a_prefix, name_a, 0);
+       quote_two_c_style(&b_name, o->b_prefix, name_b, 0);
+
        diff_populate_filespec(one, 0);
        diff_populate_filespec(two, 0);
        lc_a = count_lines(one->data, one->size);
        lc_b = count_lines(two->data, two->size);
-       printf("%s--- a/%s%s%s\n%s+++ b/%s%s%s\n%s@@ -",
-              metainfo, name_a, name_a_tab, reset,
-              metainfo, name_b, name_b_tab, reset, fraginfo);
+       printf("%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);
        print_line_count(lc_a);
        printf(" +");
        print_line_count(lc_b);
@@ -439,7 +458,7 @@ static void diff_words_show(struct diff_words_data *diff_words)
        ecb.outf = xdiff_outf;
        ecb.priv = diff_words;
        diff_words->xm.consume = fn_out_diff_words_aux;
-       xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
+       xdi_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 
        free(minus.ptr);
        free(plus.ptr);
@@ -451,9 +470,13 @@ static void diff_words_show(struct diff_words_data *diff_words)
        }
 }
 
+typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
+
 struct emit_callback {
        struct xdiff_emit_state xm;
        int nparents, color_diff;
+       unsigned ws_rule;
+       sane_truncate_fn truncate;
        const char **label_path;
        struct diff_words_data *diff_words;
        int *found_changesp;
@@ -485,75 +508,9 @@ const char *diff_get_color(int diff_use_color, enum color_diff ix)
 
 static void emit_line(const char *set, const char *reset, const char *line, int len)
 {
-       if (len > 0 && line[len-1] == '\n')
-               len--;
        fputs(set, stdout);
        fwrite(line, len, 1, stdout);
-       puts(reset);
-}
-
-static void emit_line_with_ws(int nparents,
-               const char *set, const char *reset, const char *ws,
-               const char *line, int len)
-{
-       int col0 = nparents;
-       int last_tab_in_indent = -1;
-       int last_space_in_indent = -1;
-       int i;
-       int tail = len;
-       int need_highlight_leading_space = 0;
-       /* The line is a newly added line.  Does it have funny leading
-        * whitespaces?  In indent, SP should never precede a TAB.
-        */
-       for (i = col0; i < len; i++) {
-               if (line[i] == '\t') {
-                       last_tab_in_indent = i;
-                       if (0 <= last_space_in_indent)
-                               need_highlight_leading_space = 1;
-               }
-               else if (line[i] == ' ')
-                       last_space_in_indent = i;
-               else
-                       break;
-       }
-       fputs(set, stdout);
-       fwrite(line, col0, 1, stdout);
        fputs(reset, stdout);
-       if (((i == len) || line[i] == '\n') && i != col0) {
-               /* The whole line was indent */
-               emit_line(ws, reset, line + col0, len - col0);
-               return;
-       }
-       i = col0;
-       if (need_highlight_leading_space) {
-               while (i < last_tab_in_indent) {
-                       if (line[i] == ' ') {
-                               fputs(ws, stdout);
-                               putchar(' ');
-                               fputs(reset, stdout);
-                       }
-                       else
-                               putchar(line[i]);
-                       i++;
-               }
-       }
-       tail = len - 1;
-       if (line[tail] == '\n' && i < tail)
-               tail--;
-       while (i < tail) {
-               if (!isspace(line[tail]))
-                       break;
-               tail--;
-       }
-       if ((i < tail && line[tail + 1] != '\n')) {
-               /* This has whitespace between tail+1..len */
-               fputs(set, stdout);
-               fwrite(line + i, tail - i + 1, 1, stdout);
-               fputs(reset, stdout);
-               emit_line(ws, reset, line + tail + 1, len - tail - 1);
-       }
-       else
-               emit_line(set, reset, line + i, len - i);
 }
 
 static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
@@ -563,9 +520,31 @@ static void emit_add_line(const char *reset, struct emit_callback *ecbdata, cons
 
        if (!*ws)
                emit_line(set, reset, line, len);
-       else
-               emit_line_with_ws(ecbdata->nparents, set, reset, ws,
-                               line, len);
+       else {
+               /* Emit just the prefix, then the rest. */
+               emit_line(set, reset, line, ecbdata->nparents);
+               (void)check_and_emit_line(line + ecbdata->nparents,
+                   len - ecbdata->nparents, ecbdata->ws_rule,
+                   stdout, set, reset, ws);
+       }
+}
+
+static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
+{
+       const char *cp;
+       unsigned long allot;
+       size_t l = len;
+
+       if (ecb->truncate)
+               return ecb->truncate(line, len);
+       cp = line;
+       allot = l;
+       while (0 < l) {
+               (void) utf8_width(&cp, &l);
+               if (!cp)
+                       break; /* truncated in the middle? */
+       }
+       return allot - l;
 }
 
 static void fn_out_consume(void *priv, char *line, unsigned long len)
@@ -573,7 +552,8 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
        int i;
        int color;
        struct emit_callback *ecbdata = priv;
-       const char *set = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
+       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);
 
        *(ecbdata->found_changesp) = 1;
@@ -585,9 +565,9 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 
                printf("%s--- %s%s%s\n",
-                      set, ecbdata->label_path[0], reset, name_a_tab);
+                      meta, ecbdata->label_path[0], reset, name_a_tab);
                printf("%s+++ %s%s%s\n",
-                      set, ecbdata->label_path[1], reset, name_b_tab);
+                      meta, ecbdata->label_path[1], reset, name_b_tab);
                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
        }
 
@@ -598,13 +578,15 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
                ;
        if (2 <= i && i < len && line[i] == ' ') {
                ecbdata->nparents = i - 1;
+               len = sane_truncate_line(ecbdata, line, len);
                emit_line(diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
                          reset, line, len);
+               if (line[len-1] != '\n')
+                       putchar('\n');
                return;
        }
 
        if (len < ecbdata->nparents) {
-               set = reset;
                emit_line(reset, reset, line, len);
                return;
        }
@@ -628,7 +610,7 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
                        diff_words_show(ecbdata->diff_words);
                line++;
                len--;
-               emit_line(set, reset, line, len);
+               emit_line(plain, reset, line, len);
                return;
        }
        for (i = 0; i < ecbdata->nparents && len; i++) {
@@ -720,7 +702,9 @@ struct diffstat_t {
        int nr;
        int alloc;
        struct diffstat_file {
+               char *from_name;
                char *name;
+               char *print_name;
                unsigned is_unmerged:1;
                unsigned is_binary:1;
                unsigned is_renamed:1;
@@ -741,11 +725,14 @@ static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
        }
        diffstat->files[diffstat->nr++] = x;
        if (name_b) {
-               x->name = pprint_rename(name_a, name_b);
+               x->from_name = xstrdup(name_a);
+               x->name = xstrdup(name_b);
                x->is_renamed = 1;
        }
-       else
+       else {
+               x->from_name = NULL;
                x->name = xstrdup(name_a);
+       }
        return x;
 }
 
@@ -789,6 +776,28 @@ static void show_graph(char ch, int cnt, const char *set, const char *reset)
        printf("%s", reset);
 }
 
+static void fill_print_name(struct diffstat_file *file)
+{
+       char *pname;
+
+       if (file->print_name)
+               return;
+
+       if (!file->is_renamed) {
+               struct strbuf buf;
+               strbuf_init(&buf, 0);
+               if (quote_c_style(file->name, &buf, NULL, 0)) {
+                       pname = strbuf_detach(&buf, NULL);
+               } else {
+                       pname = file->name;
+                       strbuf_release(&buf);
+               }
+       } else {
+               pname = pprint_rename(file->from_name, file->name);
+       }
+       file->print_name = pname;
+}
+
 static void show_stats(struct diffstat_t* data, struct diff_options *options)
 {
        int i, len, add, del, total, adds = 0, dels = 0;
@@ -822,19 +831,8 @@ static void show_stats(struct diffstat_t* data, struct diff_options *options)
        for (i = 0; i < data->nr; i++) {
                struct diffstat_file *file = data->files[i];
                int change = file->added + file->deleted;
-
-               if (!file->is_renamed) {  /* renames are already quoted by pprint_rename */
-                       struct strbuf buf;
-                       strbuf_init(&buf, 0);
-                       if (quote_c_style(file->name, &buf, NULL, 0)) {
-                               free(file->name);
-                               file->name = strbuf_detach(&buf, NULL);
-                       } else {
-                               strbuf_release(&buf);
-                       }
-               }
-
-               len = strlen(file->name);
+               fill_print_name(file);
+               len = strlen(file->print_name);
                if (max_len < len)
                        max_len = len;
 
@@ -859,7 +857,7 @@ static void show_stats(struct diffstat_t* data, struct diff_options *options)
 
        for (i = 0; i < data->nr; i++) {
                const char *prefix = "";
-               char *name = data->files[i]->name;
+               char *name = data->files[i]->print_name;
                int added = data->files[i]->added;
                int deleted = data->files[i]->deleted;
                int name_len;
@@ -887,17 +885,17 @@ static void show_stats(struct diffstat_t* data, struct diff_options *options)
                        printf("%s%d%s", add_c, added, reset);
                        printf(" bytes");
                        printf("\n");
-                       goto free_diffstat_file;
+                       continue;
                }
                else if (data->files[i]->is_unmerged) {
                        show_name(prefix, name, len, reset, set);
                        printf("  Unmerged\n");
-                       goto free_diffstat_file;
+                       continue;
                }
                else if (!data->files[i]->is_renamed &&
                         (added + deleted == 0)) {
                        total_files--;
-                       goto free_diffstat_file;
+                       continue;
                }
 
                /*
@@ -919,11 +917,7 @@ static void show_stats(struct diffstat_t* data, struct diff_options *options)
                show_graph('+', add, add_c, reset);
                show_graph('-', del, del_c, reset);
                putchar('\n');
-       free_diffstat_file:
-               free(data->files[i]->name);
-               free(data->files[i]);
        }
-       free(data->files);
        printf("%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
               set, total_files, adds, dels, reset);
 }
@@ -948,11 +942,7 @@ static void show_shortstats(struct diffstat_t* data)
                                dels += deleted;
                        }
                }
-               free(data->files[i]->name);
-               free(data->files[i]);
        }
-       free(data->files);
-
        printf(" %d files changed, %d insertions(+), %d deletions(-)\n",
               total_files, adds, dels);
 }
@@ -961,6 +951,9 @@ static void show_numstat(struct diffstat_t* data, struct diff_options *options)
 {
        int i;
 
+       if (data->nr == 0)
+               return;
+
        for (i = 0; i < data->nr; i++) {
                struct diffstat_file *file = data->files[i];
 
@@ -968,19 +961,45 @@ static void show_numstat(struct diffstat_t* data, struct diff_options *options)
                        printf("-\t-\t");
                else
                        printf("%d\t%d\t", file->added, file->deleted);
-               if (!file->is_renamed) {
-                       write_name_quoted(file->name, stdout, options->line_termination);
+               if (options->line_termination) {
+                       fill_print_name(file);
+                       if (!file->is_renamed)
+                               write_name_quoted(file->name, stdout,
+                                                 options->line_termination);
+                       else {
+                               fputs(file->print_name, stdout);
+                               putchar(options->line_termination);
+                       }
                } else {
-                       fputs(file->name, stdout);
-                       putchar(options->line_termination);
+                       if (file->is_renamed) {
+                               putchar('\0');
+                               write_name_quoted(file->from_name, stdout, '\0');
+                       }
+                       write_name_quoted(file->name, stdout, '\0');
                }
        }
 }
 
+static void free_diffstat_info(struct diffstat_t *diffstat)
+{
+       int i;
+       for (i = 0; i < diffstat->nr; i++) {
+               struct diffstat_file *f = diffstat->files[i];
+               if (f->name != f->print_name)
+                       free(f->print_name);
+               free(f->name);
+               free(f->from_name);
+               free(f);
+       }
+       free(diffstat->files);
+}
+
 struct checkdiff_t {
        struct xdiff_emit_state xm;
        const char *filename;
        int lineno, color_diff;
+       unsigned ws_rule;
+       unsigned status;
 };
 
 static void checkdiff_consume(void *priv, char *line, unsigned long len)
@@ -989,36 +1008,19 @@ static void checkdiff_consume(void *priv, char *line, unsigned long len)
        const char *ws = diff_get_color(data->color_diff, DIFF_WHITESPACE);
        const char *reset = diff_get_color(data->color_diff, DIFF_RESET);
        const char *set = diff_get_color(data->color_diff, DIFF_FILE_NEW);
+       char *err;
 
        if (line[0] == '+') {
-               int i, spaces = 0, space_before_tab = 0, white_space_at_end = 0;
-
-               /* check space before tab */
-               for (i = 1; i < len && (line[i] == ' ' || line[i] == '\t'); i++)
-                       if (line[i] == ' ')
-                               spaces++;
-               if (line[i - 1] == '\t' && spaces)
-                       space_before_tab = 1;
-
-               /* check white space at line end */
-               if (line[len - 1] == '\n')
-                       len--;
-               if (isspace(line[len - 1]))
-                       white_space_at_end = 1;
-
-               if (space_before_tab || white_space_at_end) {
-                       printf("%s:%d: %s", data->filename, data->lineno, ws);
-                       if (space_before_tab) {
-                               printf("space before tab");
-                               if (white_space_at_end)
-                                       putchar(',');
-                       }
-                       if (white_space_at_end)
-                               printf("white space at end");
-                       printf(":%s ", reset);
-                       emit_line_with_ws(1, set, reset, ws, line, len);
-               }
-
+               data->status = check_and_emit_line(line + 1, len - 1,
+                   data->ws_rule, NULL, NULL, NULL, NULL);
+               if (!data->status)
+                       return;
+               err = whitespace_error_string(data->status);
+               printf("%s:%d: %s.\n", data->filename, data->lineno, err);
+               free(err);
+               emit_line(set, reset, line, 1);
+               (void)check_and_emit_line(line + 1, len - 1, data->ws_rule,
+                   stdout, set, reset, ws);
                data->lineno++;
        } else if (line[0] == ' ')
                data->lineno++;
@@ -1181,7 +1183,6 @@ static const char *funcname_pattern(const char *ident)
 {
        struct funcname_pattern *pp;
 
-       read_config_if_needed();
        for (pp = funcname_pattern_list; pp; pp = pp->next)
                if (!strcmp(ident, pp->name))
                        return pp->pattern;
@@ -1223,7 +1224,7 @@ static const char *diff_funcname_pattern(struct diff_filespec *one)
 
        /*
         * And define built-in fallback patterns here.  Note that
-        * these can be overriden by the user's config settings.
+        * these can be overridden by the user's config settings.
         */
        for (i = 0; i < ARRAY_SIZE(builtin_funcname_pattern); i++)
                if (!strcmp(ident, builtin_funcname_pattern[i].name))
@@ -1246,8 +1247,8 @@ static void builtin_diff(const char *name_a,
        const char *set = diff_get_color_opt(o, DIFF_METAINFO);
        const char *reset = diff_get_color_opt(o, DIFF_RESET);
 
-       a_one = quote_two("a/", name_a + (*name_a == '/'));
-       b_two = quote_two("b/", name_b + (*name_b == '/'));
+       a_one = quote_two(o->a_prefix, name_a + (*name_a == '/'));
+       b_two = quote_two(o->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";
        printf("%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
@@ -1276,8 +1277,7 @@ static void builtin_diff(const char *name_a,
                if ((one->mode ^ two->mode) & S_IFMT)
                        goto free_ab_and_return;
                if (complete_rewrite) {
-                       emit_rewrite_diff(name_a, name_b, one, two,
-                                       DIFF_OPT_TST(o, COLOR_DIFF));
+                       emit_rewrite_diff(name_a, name_b, one, two, o);
                        o->found_changes = 1;
                        goto free_ab_and_return;
                }
@@ -1317,6 +1317,7 @@ static void builtin_diff(const char *name_a,
                ecbdata.label_path = lbl;
                ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
                ecbdata.found_changesp = &o->found_changes;
+               ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
                xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
                xecfg.ctxlen = o->context;
                xecfg.flags = XDL_EMIT_FUNCNAMES;
@@ -1334,7 +1335,7 @@ static void builtin_diff(const char *name_a,
                if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
                        ecbdata.diff_words =
                                xcalloc(1, sizeof(struct diff_words_data));
-               xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
+               xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
                if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
                        free_diff_words_data(&ecbdata);
        }
@@ -1387,7 +1388,7 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
                xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
                ecb.outf = xdiff_outf;
                ecb.priv = diffstat;
-               xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
+               xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
        }
 
  free_and_return:
@@ -1410,6 +1411,7 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
        data.filename = name_b ? name_b : name_a;
        data.lineno = 0;
        data.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
+       data.ws_rule = whitespace_rule(data.filename);
 
        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
                die("unable to read files to diff");
@@ -1426,11 +1428,13 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
                xpp.flags = XDF_NEED_MINIMAL;
                ecb.outf = xdiff_outf;
                ecb.priv = &data;
-               xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
+               xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
        }
  free_and_return:
        diff_free_filespec_data(one);
        diff_free_filespec_data(two);
+       if (data.status)
+               DIFF_OPT_SET(o, CHECK_FAILED);
 }
 
 struct diff_filespec *alloc_filespec(const char *path)
@@ -1835,7 +1839,6 @@ static const char *external_diff_attr(const char *name)
                    !ATTR_UNSET(value)) {
                        struct ll_diff_driver *drv;
 
-                       read_config_if_needed();
                        for (drv = user_diff; drv; drv = drv->next)
                                if (!strcmp(drv->name, value))
                                        return drv->cmd;
@@ -2050,6 +2053,9 @@ void diff_setup(struct diff_options *options)
        else
                DIFF_OPT_CLR(options, COLOR_DIFF);
        options->detect_rename = diff_detect_rename_default;
+
+       options->a_prefix = "a/";
+       options->b_prefix = "b/";
 }
 
 int diff_setup_done(struct diff_options *options)
@@ -2321,6 +2327,12 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
                else if (40 < options->abbrev)
                        options->abbrev = 40;
        }
+       else if (!prefixcmp(arg, "--src-prefix="))
+               options->a_prefix = arg + 13;
+       else if (!prefixcmp(arg, "--dst-prefix="))
+               options->b_prefix = arg + 13;
+       else if (!strcmp(arg, "--no-prefix"))
+               options->a_prefix = options->b_prefix = "";
        else
                return 0;
        return 1;
@@ -2716,7 +2728,7 @@ static void diff_summary(struct diff_filepair *p)
                break;
        default:
                if (p->score) {
-                       puts(" rewrite ");
+                       fputs(" rewrite ", stdout);
                        write_name_quoted(p->two->path, stdout, ' ');
                        printf("(%d%%)\n", similarity_index(p));
                }
@@ -2838,7 +2850,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
                xecfg.flags = XDL_EMIT_FUNCNAMES;
                ecb.outf = xdiff_outf;
                ecb.priv = &data;
-               xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
+               xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
        }
 
        SHA1_Final(sha1, &ctx);
@@ -2925,8 +2937,9 @@ void diff_flush(struct diff_options *options)
                        show_numstat(&diffstat, options);
                if (output_format & DIFF_FORMAT_DIFFSTAT)
                        show_stats(&diffstat, options);
-               else if (output_format & DIFF_FORMAT_SHORTSTAT)
+               if (output_format & DIFF_FORMAT_SHORTSTAT)
                        show_shortstats(&diffstat);
+               free_diffstat_info(&diffstat);
                separator++;
        }
 
@@ -3110,6 +3123,20 @@ void diffcore_std(struct diff_options *options)
                DIFF_OPT_CLR(options, HAS_CHANGES);
 }
 
+int diff_result_code(struct diff_options *opt, int status)
+{
+       int result = 0;
+       if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
+           !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
+               return status;
+       if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
+           DIFF_OPT_TST(opt, HAS_CHANGES))
+               result |= 01;
+       if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
+           DIFF_OPT_TST(opt, CHECK_FAILED))
+               result |= 02;
+       return result;
+}
 
 void diff_addremove(struct diff_options *options,
                    int addremove, unsigned mode,