diff: avoid redundantly clearing a flag
[gitweb.git] / diff.c
diff --git a/diff.c b/diff.c
index 5c428e02b6a3fc49475a0ac05cad634708276059..23311f9c006a93d6691b9b2202ec24906047257f 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -16,6 +16,7 @@
 #include "userdiff.h"
 #include "submodule-config.h"
 #include "submodule.h"
+#include "hashmap.h"
 #include "ll-merge.h"
 #include "string-list.h"
 #include "argv-array.h"
@@ -32,6 +33,7 @@ static int diff_indent_heuristic = 1;
 static int diff_rename_limit_default = 400;
 static int diff_suppress_blank_empty;
 static int diff_use_color_default = -1;
+static int diff_color_moved_default;
 static int diff_context_default = 3;
 static int diff_interhunk_context_default;
 static const char *diff_word_regex_cfg;
@@ -56,6 +58,14 @@ static char diff_colors[][COLOR_MAXLEN] = {
        GIT_COLOR_YELLOW,       /* COMMIT */
        GIT_COLOR_BG_RED,       /* WHITESPACE */
        GIT_COLOR_NORMAL,       /* FUNCINFO */
+       GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
+       GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
+       GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
+       GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
+       GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
+       GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
+       GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
+       GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
 };
 
 static NORETURN void die_want_option(const char *option_name)
@@ -81,6 +91,22 @@ static int parse_diff_color_slot(const char *var)
                return DIFF_WHITESPACE;
        if (!strcasecmp(var, "func"))
                return DIFF_FUNCINFO;
+       if (!strcasecmp(var, "oldmoved"))
+               return DIFF_FILE_OLD_MOVED;
+       if (!strcasecmp(var, "oldmovedalternative"))
+               return DIFF_FILE_OLD_MOVED_ALT;
+       if (!strcasecmp(var, "oldmoveddimmed"))
+               return DIFF_FILE_OLD_MOVED_DIM;
+       if (!strcasecmp(var, "oldmovedalternativedimmed"))
+               return DIFF_FILE_OLD_MOVED_ALT_DIM;
+       if (!strcasecmp(var, "newmoved"))
+               return DIFF_FILE_NEW_MOVED;
+       if (!strcasecmp(var, "newmovedalternative"))
+               return DIFF_FILE_NEW_MOVED_ALT;
+       if (!strcasecmp(var, "newmoveddimmed"))
+               return DIFF_FILE_NEW_MOVED_DIM;
+       if (!strcasecmp(var, "newmovedalternativedimmed"))
+               return DIFF_FILE_NEW_MOVED_ALT_DIM;
        return -1;
 }
 
@@ -229,12 +255,44 @@ int git_diff_heuristic_config(const char *var, const char *value, void *cb)
        return 0;
 }
 
+static int parse_color_moved(const char *arg)
+{
+       switch (git_parse_maybe_bool(arg)) {
+       case 0:
+               return COLOR_MOVED_NO;
+       case 1:
+               return COLOR_MOVED_DEFAULT;
+       default:
+               break;
+       }
+
+       if (!strcmp(arg, "no"))
+               return COLOR_MOVED_NO;
+       else if (!strcmp(arg, "plain"))
+               return COLOR_MOVED_PLAIN;
+       else if (!strcmp(arg, "zebra"))
+               return COLOR_MOVED_ZEBRA;
+       else if (!strcmp(arg, "default"))
+               return COLOR_MOVED_DEFAULT;
+       else if (!strcmp(arg, "dimmed_zebra"))
+               return COLOR_MOVED_ZEBRA_DIM;
+       else
+               return error(_("color moved setting must be one of 'no', 'default', 'zebra', 'dimmed_zebra', 'plain'"));
+}
+
 int git_diff_ui_config(const char *var, const char *value, void *cb)
 {
        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
                diff_use_color_default = git_config_colorbool(var, value);
                return 0;
        }
+       if (!strcmp(var, "diff.colormoved")) {
+               int cm = parse_color_moved(value);
+               if (cm < 0)
+                       return -1;
+               diff_color_moved_default = cm;
+               return 0;
+       }
        if (!strcmp(var, "diff.context")) {
                diff_context_default = git_config_int(var, value);
                if (diff_context_default < 0)
@@ -561,6 +619,25 @@ static void emit_line(struct diff_options *o, const char *set, const char *reset
 }
 
 enum diff_symbol {
+       DIFF_SYMBOL_BINARY_DIFF_HEADER,
+       DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
+       DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
+       DIFF_SYMBOL_BINARY_DIFF_BODY,
+       DIFF_SYMBOL_BINARY_DIFF_FOOTER,
+       DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
+       DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
+       DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
+       DIFF_SYMBOL_STATS_LINE,
+       DIFF_SYMBOL_WORD_DIFF,
+       DIFF_SYMBOL_STAT_SEP,
+       DIFF_SYMBOL_SUMMARY,
+       DIFF_SYMBOL_SUBMODULE_ADD,
+       DIFF_SYMBOL_SUBMODULE_DEL,
+       DIFF_SYMBOL_SUBMODULE_UNTRACKED,
+       DIFF_SYMBOL_SUBMODULE_MODIFIED,
+       DIFF_SYMBOL_SUBMODULE_HEADER,
+       DIFF_SYMBOL_SUBMODULE_ERROR,
+       DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
        DIFF_SYMBOL_REWRITE_DIFF,
        DIFF_SYMBOL_BINARY_FILES,
        DIFF_SYMBOL_HEADER,
@@ -583,9 +660,355 @@ enum diff_symbol {
  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
  * 16 is marking if the line is blank at EOF
  */
-#define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF (1<<16)
+#define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF     (1<<16)
+#define DIFF_SYMBOL_MOVED_LINE                 (1<<17)
+#define DIFF_SYMBOL_MOVED_LINE_ALT             (1<<18)
+#define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING   (1<<19)
 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 
+/*
+ * This struct is used when we need to buffer the output of the diff output.
+ *
+ * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
+ * into the pre/post image file. This pointer could be a union with the
+ * line pointer. By storing an offset into the file instead of the literal line,
+ * we can decrease the memory footprint for the buffered output. At first we
+ * may want to only have indirection for the content lines, but we could also
+ * enhance the state for emitting prefabricated lines, e.g. the similarity
+ * score line or hunk/file headers would only need to store a number or path
+ * and then the output can be constructed later on depending on state.
+ */
+struct emitted_diff_symbol {
+       const char *line;
+       int len;
+       int flags;
+       enum diff_symbol s;
+};
+#define EMITTED_DIFF_SYMBOL_INIT {NULL}
+
+struct emitted_diff_symbols {
+       struct emitted_diff_symbol *buf;
+       int nr, alloc;
+};
+#define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
+
+static void append_emitted_diff_symbol(struct diff_options *o,
+                                      struct emitted_diff_symbol *e)
+{
+       struct emitted_diff_symbol *f;
+
+       ALLOC_GROW(o->emitted_symbols->buf,
+                  o->emitted_symbols->nr + 1,
+                  o->emitted_symbols->alloc);
+       f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
+
+       memcpy(f, e, sizeof(struct emitted_diff_symbol));
+       f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
+}
+
+struct moved_entry {
+       struct hashmap_entry ent;
+       const struct emitted_diff_symbol *es;
+       struct moved_entry *next_line;
+};
+
+static int next_byte(const char **cp, const char **endp,
+                    const struct diff_options *diffopt)
+{
+       int retval;
+
+       if (*cp > *endp)
+               return -1;
+
+       if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_CHANGE)) {
+               while (*cp < *endp && isspace(**cp))
+                       (*cp)++;
+               /*
+                * After skipping a couple of whitespaces, we still have to
+                * account for one space.
+                */
+               return (int)' ';
+       }
+
+       if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE)) {
+               while (*cp < *endp && isspace(**cp))
+                       (*cp)++;
+               /* return the first non-ws character via the usual below */
+       }
+
+       retval = (unsigned char)(**cp);
+       (*cp)++;
+       return retval;
+}
+
+static int moved_entry_cmp(const struct diff_options *diffopt,
+                          const struct moved_entry *a,
+                          const struct moved_entry *b,
+                          const void *keydata)
+{
+       const char *ap = a->es->line, *ae = a->es->line + a->es->len;
+       const char *bp = b->es->line, *be = b->es->line + b->es->len;
+
+       if (!(diffopt->xdl_opts & XDF_WHITESPACE_FLAGS))
+               return a->es->len != b->es->len  || memcmp(ap, bp, a->es->len);
+
+       if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_AT_EOL)) {
+               while (ae > ap && isspace(*ae))
+                       ae--;
+               while (be > bp && isspace(*be))
+                       be--;
+       }
+
+       while (1) {
+               int ca, cb;
+               ca = next_byte(&ap, &ae, diffopt);
+               cb = next_byte(&bp, &be, diffopt);
+               if (ca != cb)
+                       return 1;
+               if (ca < 0)
+                       return 0;
+       }
+}
+
+static unsigned get_string_hash(struct emitted_diff_symbol *es, struct diff_options *o)
+{
+       if (o->xdl_opts & XDF_WHITESPACE_FLAGS) {
+               static struct strbuf sb = STRBUF_INIT;
+               const char *ap = es->line, *ae = es->line + es->len;
+               int c;
+
+               strbuf_reset(&sb);
+               while (ae > ap && isspace(*ae))
+                       ae--;
+               while ((c = next_byte(&ap, &ae, o)) > 0)
+                       strbuf_addch(&sb, c);
+
+               return memhash(sb.buf, sb.len);
+       } else {
+               return memhash(es->line, es->len);
+       }
+}
+
+static struct moved_entry *prepare_entry(struct diff_options *o,
+                                        int line_no)
+{
+       struct moved_entry *ret = xmalloc(sizeof(*ret));
+       struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
+
+       ret->ent.hash = get_string_hash(l, o);
+       ret->es = l;
+       ret->next_line = NULL;
+
+       return ret;
+}
+
+static void add_lines_to_move_detection(struct diff_options *o,
+                                       struct hashmap *add_lines,
+                                       struct hashmap *del_lines)
+{
+       struct moved_entry *prev_line = NULL;
+
+       int n;
+       for (n = 0; n < o->emitted_symbols->nr; n++) {
+               struct hashmap *hm;
+               struct moved_entry *key;
+
+               switch (o->emitted_symbols->buf[n].s) {
+               case DIFF_SYMBOL_PLUS:
+                       hm = add_lines;
+                       break;
+               case DIFF_SYMBOL_MINUS:
+                       hm = del_lines;
+                       break;
+               default:
+                       prev_line = NULL;
+                       continue;
+               }
+
+               key = prepare_entry(o, n);
+               if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
+                       prev_line->next_line = key;
+
+               hashmap_add(hm, key);
+               prev_line = key;
+       }
+}
+
+static int shrink_potential_moved_blocks(struct moved_entry **pmb,
+                                        int pmb_nr)
+{
+       int lp, rp;
+
+       /* Shrink the set of potential block to the remaining running */
+       for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
+               while (lp < pmb_nr && pmb[lp])
+                       lp++;
+               /* lp points at the first NULL now */
+
+               while (rp > -1 && !pmb[rp])
+                       rp--;
+               /* rp points at the last non-NULL */
+
+               if (lp < pmb_nr && rp > -1 && lp < rp) {
+                       pmb[lp] = pmb[rp];
+                       pmb[rp] = NULL;
+                       rp--;
+                       lp++;
+               }
+       }
+
+       /* Remember the number of running sets */
+       return rp + 1;
+}
+
+/* Find blocks of moved code, delegate actual coloring decision to helper */
+static void mark_color_as_moved(struct diff_options *o,
+                               struct hashmap *add_lines,
+                               struct hashmap *del_lines)
+{
+       struct moved_entry **pmb = NULL; /* potentially moved blocks */
+       int pmb_nr = 0, pmb_alloc = 0;
+       int n, flipped_block = 1, block_length = 0;
+
+
+       for (n = 0; n < o->emitted_symbols->nr; n++) {
+               struct hashmap *hm = NULL;
+               struct moved_entry *key;
+               struct moved_entry *match = NULL;
+               struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
+               int i;
+
+               switch (l->s) {
+               case DIFF_SYMBOL_PLUS:
+                       hm = del_lines;
+                       key = prepare_entry(o, n);
+                       match = hashmap_get(hm, key, o);
+                       free(key);
+                       break;
+               case DIFF_SYMBOL_MINUS:
+                       hm = add_lines;
+                       key = prepare_entry(o, n);
+                       match = hashmap_get(hm, key, o);
+                       free(key);
+                       break;
+               default:
+                       flipped_block = 1;
+               }
+
+               if (!match) {
+                       if (block_length < COLOR_MOVED_MIN_BLOCK_LENGTH &&
+                           o->color_moved != COLOR_MOVED_PLAIN) {
+                               for (i = 1; i < block_length + 1; i++) {
+                                       l = &o->emitted_symbols->buf[n - i];
+                                       l->flags &= ~DIFF_SYMBOL_MOVED_LINE;
+                               }
+                       }
+                       pmb_nr = 0;
+                       block_length = 0;
+                       continue;
+               }
+
+               l->flags |= DIFF_SYMBOL_MOVED_LINE;
+               block_length++;
+
+               if (o->color_moved == COLOR_MOVED_PLAIN)
+                       continue;
+
+               /* Check any potential block runs, advance each or nullify */
+               for (i = 0; i < pmb_nr; i++) {
+                       struct moved_entry *p = pmb[i];
+                       struct moved_entry *pnext = (p && p->next_line) ?
+                                       p->next_line : NULL;
+                       if (pnext && !hm->cmpfn(o, pnext, match, NULL)) {
+                               pmb[i] = p->next_line;
+                       } else {
+                               pmb[i] = NULL;
+                       }
+               }
+
+               pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
+
+               if (pmb_nr == 0) {
+                       /*
+                        * The current line is the start of a new block.
+                        * Setup the set of potential blocks.
+                        */
+                       for (; match; match = hashmap_get_next(hm, match)) {
+                               ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
+                               pmb[pmb_nr++] = match;
+                       }
+
+                       flipped_block = (flipped_block + 1) % 2;
+               }
+
+               if (flipped_block)
+                       l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
+       }
+
+       free(pmb);
+}
+
+#define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
+  (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
+static void dim_moved_lines(struct diff_options *o)
+{
+       int n;
+       for (n = 0; n < o->emitted_symbols->nr; n++) {
+               struct emitted_diff_symbol *prev = (n != 0) ?
+                               &o->emitted_symbols->buf[n - 1] : NULL;
+               struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
+               struct emitted_diff_symbol *next =
+                               (n < o->emitted_symbols->nr - 1) ?
+                               &o->emitted_symbols->buf[n + 1] : NULL;
+
+               /* Not a plus or minus line? */
+               if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
+                       continue;
+
+               /* Not a moved line? */
+               if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
+                       continue;
+
+               /*
+                * If prev or next are not a plus or minus line,
+                * pretend they don't exist
+                */
+               if (prev && prev->s != DIFF_SYMBOL_PLUS &&
+                           prev->s != DIFF_SYMBOL_MINUS)
+                       prev = NULL;
+               if (next && next->s != DIFF_SYMBOL_PLUS &&
+                           next->s != DIFF_SYMBOL_MINUS)
+                       next = NULL;
+
+               /* Inside a block? */
+               if ((prev &&
+                   (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
+                   (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
+                   (next &&
+                   (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
+                   (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
+                       l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
+                       continue;
+               }
+
+               /* Check if we are at an interesting bound: */
+               if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
+                   (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
+                      (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
+                       continue;
+               if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
+                   (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
+                      (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
+                       continue;
+
+               /*
+                * The boundary to prev and next are not interesting,
+                * so this line is not interesting as a whole
+                */
+               l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
+       }
+}
+
 static void emit_line_ws_markup(struct diff_options *o,
                                const char *set, const char *reset,
                                const char *line, int len, char sign,
@@ -612,11 +1035,18 @@ static void emit_line_ws_markup(struct diff_options *o,
        }
 }
 
-static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
-                            const char *line, int len, unsigned flags)
+static void emit_diff_symbol_from_struct(struct diff_options *o,
+                                        struct emitted_diff_symbol *eds)
 {
        static const char *nneof = " No newline at end of file\n";
        const char *context, *reset, *set, *meta, *fraginfo;
+       struct strbuf sb = STRBUF_INIT;
+
+       enum diff_symbol s = eds->s;
+       const char *line = eds->line;
+       int len = eds->len;
+       unsigned flags = eds->flags;
+
        switch (s) {
        case DIFF_SYMBOL_NO_LF_EOF:
                context = diff_get_color_opt(o, DIFF_CONTEXT);
@@ -625,6 +1055,13 @@ static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
                emit_line_0(o, context, reset, '\\',
                            nneof, strlen(nneof));
                break;
+       case DIFF_SYMBOL_SUBMODULE_HEADER:
+       case DIFF_SYMBOL_SUBMODULE_ERROR:
+       case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
+       case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
+       case DIFF_SYMBOL_SUMMARY:
+       case DIFF_SYMBOL_STATS_LINE:
+       case DIFF_SYMBOL_BINARY_DIFF_BODY:
        case DIFF_SYMBOL_CONTEXT_FRAGINFO:
                emit_line(o, "", "", line, len);
                break;
@@ -646,14 +1083,56 @@ static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
                                    flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
                break;
        case DIFF_SYMBOL_PLUS:
-               set = diff_get_color_opt(o, DIFF_FILE_NEW);
+               switch (flags & (DIFF_SYMBOL_MOVED_LINE |
+                                DIFF_SYMBOL_MOVED_LINE_ALT |
+                                DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
+               case DIFF_SYMBOL_MOVED_LINE |
+                    DIFF_SYMBOL_MOVED_LINE_ALT |
+                    DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
+                       set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
+                       break;
+               case DIFF_SYMBOL_MOVED_LINE |
+                    DIFF_SYMBOL_MOVED_LINE_ALT:
+                       set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
+                       break;
+               case DIFF_SYMBOL_MOVED_LINE |
+                    DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
+                       set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
+                       break;
+               case DIFF_SYMBOL_MOVED_LINE:
+                       set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
+                       break;
+               default:
+                       set = diff_get_color_opt(o, DIFF_FILE_NEW);
+               }
                reset = diff_get_color_opt(o, DIFF_RESET);
                emit_line_ws_markup(o, set, reset, line, len, '+',
                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK,
                                    flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
                break;
        case DIFF_SYMBOL_MINUS:
-               set = diff_get_color_opt(o, DIFF_FILE_OLD);
+               switch (flags & (DIFF_SYMBOL_MOVED_LINE |
+                                DIFF_SYMBOL_MOVED_LINE_ALT |
+                                DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
+               case DIFF_SYMBOL_MOVED_LINE |
+                    DIFF_SYMBOL_MOVED_LINE_ALT |
+                    DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
+                       set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
+                       break;
+               case DIFF_SYMBOL_MOVED_LINE |
+                    DIFF_SYMBOL_MOVED_LINE_ALT:
+                       set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
+                       break;
+               case DIFF_SYMBOL_MOVED_LINE |
+                    DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
+                       set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
+                       break;
+               case DIFF_SYMBOL_MOVED_LINE:
+                       set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
+                       break;
+               default:
+                       set = diff_get_color_opt(o, DIFF_FILE_OLD);
+               }
                reset = diff_get_color_opt(o, DIFF_RESET);
                emit_line_ws_markup(o, set, reset, line, len, '-',
                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
@@ -696,14 +1175,109 @@ static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
        case DIFF_SYMBOL_HEADER:
                fprintf(o->file, "%s", line);
                break;
+       case DIFF_SYMBOL_BINARY_DIFF_HEADER:
+               fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
+               break;
+       case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
+               fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
+               break;
+       case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
+               fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
+               break;
+       case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
+               fputs(diff_line_prefix(o), o->file);
+               fputc('\n', o->file);
+               break;
        case DIFF_SYMBOL_REWRITE_DIFF:
                fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
                reset = diff_get_color_opt(o, DIFF_RESET);
                emit_line(o, fraginfo, reset, line, len);
                break;
+       case DIFF_SYMBOL_SUBMODULE_ADD:
+               set = diff_get_color_opt(o, DIFF_FILE_NEW);
+               reset = diff_get_color_opt(o, DIFF_RESET);
+               emit_line(o, set, reset, line, len);
+               break;
+       case DIFF_SYMBOL_SUBMODULE_DEL:
+               set = diff_get_color_opt(o, DIFF_FILE_OLD);
+               reset = diff_get_color_opt(o, DIFF_RESET);
+               emit_line(o, set, reset, line, len);
+               break;
+       case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
+               fprintf(o->file, "%sSubmodule %s contains untracked content\n",
+                       diff_line_prefix(o), line);
+               break;
+       case DIFF_SYMBOL_SUBMODULE_MODIFIED:
+               fprintf(o->file, "%sSubmodule %s contains modified content\n",
+                       diff_line_prefix(o), line);
+               break;
+       case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
+               emit_line(o, "", "", " 0 files changed\n",
+                         strlen(" 0 files changed\n"));
+               break;
+       case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
+               emit_line(o, "", "", " ...\n", strlen(" ...\n"));
+               break;
+       case DIFF_SYMBOL_WORD_DIFF:
+               fprintf(o->file, "%.*s", len, line);
+               break;
+       case DIFF_SYMBOL_STAT_SEP:
+               fputs(o->stat_sep, o->file);
+               break;
        default:
                die("BUG: unknown diff symbol");
        }
+       strbuf_release(&sb);
+}
+
+static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
+                            const char *line, int len, unsigned flags)
+{
+       struct emitted_diff_symbol e = {line, len, flags, s};
+
+       if (o->emitted_symbols)
+               append_emitted_diff_symbol(o, &e);
+       else
+               emit_diff_symbol_from_struct(o, &e);
+}
+
+void diff_emit_submodule_del(struct diff_options *o, const char *line)
+{
+       emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
+}
+
+void diff_emit_submodule_add(struct diff_options *o, const char *line)
+{
+       emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
+}
+
+void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
+{
+       emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
+                        path, strlen(path), 0);
+}
+
+void diff_emit_submodule_modified(struct diff_options *o, const char *path)
+{
+       emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
+                        path, strlen(path), 0);
+}
+
+void diff_emit_submodule_header(struct diff_options *o, const char *header)
+{
+       emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
+                        header, strlen(header), 0);
+}
+
+void diff_emit_submodule_error(struct diff_options *o, const char *err)
+{
+       emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
+}
+
+void diff_emit_submodule_pipethrough(struct diff_options *o,
+                                    const char *line, int len)
+{
+       emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
 }
 
 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
@@ -991,37 +1565,49 @@ struct diff_words_data {
        struct diff_words_style *style;
 };
 
-static int fn_out_diff_words_write_helper(FILE *fp,
+static int fn_out_diff_words_write_helper(struct diff_options *o,
                                          struct diff_words_style_elem *st_el,
                                          const char *newline,
-                                         size_t count, const char *buf,
-                                         const char *line_prefix)
+                                         size_t count, const char *buf)
 {
        int print = 0;
+       struct strbuf sb = STRBUF_INIT;
 
        while (count) {
                char *p = memchr(buf, '\n', count);
                if (print)
-                       fputs(line_prefix, fp);
+                       strbuf_addstr(&sb, diff_line_prefix(o));
+
                if (p != buf) {
-                       if (st_el->color && fputs(st_el->color, fp) < 0)
-                               return -1;
-                       if (fputs(st_el->prefix, fp) < 0 ||
-                           fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
-                           fputs(st_el->suffix, fp) < 0)
-                               return -1;
-                       if (st_el->color && *st_el->color
-                           && fputs(GIT_COLOR_RESET, fp) < 0)
-                               return -1;
+                       const char *reset = st_el->color && *st_el->color ?
+                                           GIT_COLOR_RESET : NULL;
+                       if (st_el->color && *st_el->color)
+                               strbuf_addstr(&sb, st_el->color);
+                       strbuf_addstr(&sb, st_el->prefix);
+                       strbuf_add(&sb, buf, p ? p - buf : count);
+                       strbuf_addstr(&sb, st_el->suffix);
+                       if (reset)
+                               strbuf_addstr(&sb, reset);
                }
                if (!p)
-                       return 0;
-               if (fputs(newline, fp) < 0)
-                       return -1;
+                       goto out;
+
+               strbuf_addstr(&sb, newline);
                count -= p + 1 - buf;
                buf = p + 1;
                print = 1;
+               if (count) {
+                       emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
+                                        sb.buf, sb.len, 0);
+                       strbuf_reset(&sb);
+               }
        }
+
+out:
+       if (sb.len)
+               emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
+                                sb.buf, sb.len, 0);
+       strbuf_release(&sb);
        return 0;
 }
 
@@ -1103,24 +1689,20 @@ static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
                fputs(line_prefix, diff_words->opt->file);
        }
        if (diff_words->current_plus != plus_begin) {
-               fn_out_diff_words_write_helper(diff_words->opt->file,
+               fn_out_diff_words_write_helper(diff_words->opt,
                                &style->ctx, style->newline,
                                plus_begin - diff_words->current_plus,
-                               diff_words->current_plus, line_prefix);
-               if (*(plus_begin - 1) == '\n')
-                       fputs(line_prefix, diff_words->opt->file);
+                               diff_words->current_plus);
        }
        if (minus_begin != minus_end) {
-               fn_out_diff_words_write_helper(diff_words->opt->file,
+               fn_out_diff_words_write_helper(diff_words->opt,
                                &style->old, style->newline,
-                               minus_end - minus_begin, minus_begin,
-                               line_prefix);
+                               minus_end - minus_begin, minus_begin);
        }
        if (plus_begin != plus_end) {
-               fn_out_diff_words_write_helper(diff_words->opt->file,
+               fn_out_diff_words_write_helper(diff_words->opt,
                                &style->new, style->newline,
-                               plus_end - plus_begin, plus_begin,
-                               line_prefix);
+                               plus_end - plus_begin, plus_begin);
        }
 
        diff_words->current_plus = plus_end;
@@ -1214,11 +1796,12 @@ static void diff_words_show(struct diff_words_data *diff_words)
 
        /* special case: only removal */
        if (!diff_words->plus.text.size) {
-               fputs(line_prefix, diff_words->opt->file);
-               fn_out_diff_words_write_helper(diff_words->opt->file,
+               emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
+                                line_prefix, strlen(line_prefix), 0);
+               fn_out_diff_words_write_helper(diff_words->opt,
                        &style->old, style->newline,
                        diff_words->minus.text.size,
-                       diff_words->minus.text.ptr, line_prefix);
+                       diff_words->minus.text.ptr);
                diff_words->minus.text.size = 0;
                return;
        }
@@ -1241,12 +1824,12 @@ static void diff_words_show(struct diff_words_data *diff_words)
        if (diff_words->current_plus != diff_words->plus.text.ptr +
                        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,
+                       emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
+                                        line_prefix, strlen(line_prefix), 0);
+               fn_out_diff_words_write_helper(diff_words->opt,
                        &style->ctx, style->newline,
                        diff_words->plus.text.ptr + diff_words->plus.text.size
-                       - diff_words->current_plus, diff_words->current_plus,
-                       line_prefix);
+                       - diff_words->current_plus, diff_words->current_plus);
        }
        diff_words->minus.text.size = diff_words->plus.text.size = 0;
 }
@@ -1254,9 +1837,29 @@ static void diff_words_show(struct diff_words_data *diff_words)
 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
 static void diff_words_flush(struct emit_callback *ecbdata)
 {
+       struct diff_options *wo = ecbdata->diff_words->opt;
+
        if (ecbdata->diff_words->minus.text.size ||
            ecbdata->diff_words->plus.text.size)
                diff_words_show(ecbdata->diff_words);
+
+       if (wo->emitted_symbols) {
+               struct diff_options *o = ecbdata->opt;
+               struct emitted_diff_symbols *wol = wo->emitted_symbols;
+               int i;
+
+               /*
+                * NEEDSWORK:
+                * Instead of appending each, concat all words to a line?
+                */
+               for (i = 0; i < wol->nr; i++)
+                       append_emitted_diff_symbol(o, &wol->buf[i]);
+
+               for (i = 0; i < wol->nr; i++)
+                       free((void *)wol->buf[i].line);
+
+               wol->nr = 0;
+       }
 }
 
 static void diff_filespec_load_driver(struct diff_filespec *one)
@@ -1292,6 +1895,11 @@ static void init_diff_words_data(struct emit_callback *ecbdata,
                xcalloc(1, sizeof(struct diff_words_data));
        ecbdata->diff_words->type = o->word_diff;
        ecbdata->diff_words->opt = o;
+
+       if (orig_opts->emitted_symbols)
+               o->emitted_symbols =
+                       xcalloc(1, sizeof(struct emitted_diff_symbols));
+
        if (!o->word_regex)
                o->word_regex = userdiff_word_regex(one);
        if (!o->word_regex)
@@ -1326,6 +1934,7 @@ static void free_diff_words_data(struct emit_callback *ecbdata)
 {
        if (ecbdata->diff_words) {
                diff_words_flush(ecbdata);
+               free (ecbdata->diff_words->opt->emitted_symbols);
                free (ecbdata->diff_words->opt);
                free (ecbdata->diff_words->minus.text.ptr);
                free (ecbdata->diff_words->minus.orig);
@@ -1619,20 +2228,14 @@ static int scale_linear(int it, int width, int max_change)
        return 1 + (it * (width - 1) / max_change);
 }
 
-static void show_name(FILE *file,
-                     const char *prefix, const char *name, int len)
-{
-       fprintf(file, " %s%-*s |", prefix, len, name);
-}
-
-static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
+static void show_graph(struct strbuf *out, char ch, int cnt,
+                      const char *set, const char *reset)
 {
        if (cnt <= 0)
                return;
-       fprintf(file, "%s", set);
-       while (cnt--)
-               putc(ch, file);
-       fprintf(file, "%s", reset);
+       strbuf_addstr(out, set);
+       strbuf_addchars(out, ch, cnt);
+       strbuf_addstr(out, reset);
 }
 
 static void fill_print_name(struct diffstat_file *file)
@@ -1656,14 +2259,16 @@ static void fill_print_name(struct diffstat_file *file)
        file->print_name = pname;
 }
 
-int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
+static void print_stat_summary_inserts_deletes(struct diff_options *options,
+               int files, int insertions, int deletions)
 {
        struct strbuf sb = STRBUF_INIT;
-       int ret;
 
        if (!files) {
                assert(insertions == 0 && deletions == 0);
-               return fprintf(fp, "%s\n", " 0 files changed");
+               emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
+                                NULL, 0, 0);
+               return;
        }
 
        strbuf_addf(&sb,
@@ -1690,9 +2295,19 @@ int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
                            deletions);
        }
        strbuf_addch(&sb, '\n');
-       ret = fputs(sb.buf, fp);
+       emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
+                        sb.buf, sb.len, 0);
        strbuf_release(&sb);
-       return ret;
+}
+
+void print_stat_summary(FILE *fp, int files,
+                       int insertions, int deletions)
+{
+       struct diff_options o;
+       memset(&o, 0, sizeof(o));
+       o.file = fp;
+
+       print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
 }
 
 static void show_stats(struct diffstat_t *data, struct diff_options *options)
@@ -1702,13 +2317,13 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
        int total_files = data->nr, count;
        int width, name_width, graph_width, number_width = 0, bin_width = 0;
        const char *reset, *add_c, *del_c;
-       const char *line_prefix = "";
        int extra_shown = 0;
+       const char *line_prefix = diff_line_prefix(options);
+       struct strbuf out = STRBUF_INIT;
 
        if (data->nr == 0)
                return;
 
-       line_prefix = diff_line_prefix(options);
        count = options->stat_count ? options->stat_count : data->nr;
 
        reset = diff_get_color_opt(options, DIFF_RESET);
@@ -1862,26 +2477,32 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
                }
 
                if (file->is_binary) {
-                       fprintf(options->file, "%s", line_prefix);
-                       show_name(options->file, prefix, name, len);
-                       fprintf(options->file, " %*s", number_width, "Bin");
+                       strbuf_addf(&out, " %s%-*s |", prefix, len, name);
+                       strbuf_addf(&out, " %*s", number_width, "Bin");
                        if (!added && !deleted) {
-                               putc('\n', options->file);
+                               strbuf_addch(&out, '\n');
+                               emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
+                                                out.buf, out.len, 0);
+                               strbuf_reset(&out);
                                continue;
                        }
-                       fprintf(options->file, " %s%"PRIuMAX"%s",
+                       strbuf_addf(&out, " %s%"PRIuMAX"%s",
                                del_c, deleted, reset);
-                       fprintf(options->file, " -> ");
-                       fprintf(options->file, "%s%"PRIuMAX"%s",
+                       strbuf_addstr(&out, " -> ");
+                       strbuf_addf(&out, "%s%"PRIuMAX"%s",
                                add_c, added, reset);
-                       fprintf(options->file, " bytes");
-                       fprintf(options->file, "\n");
+                       strbuf_addstr(&out, " bytes\n");
+                       emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
+                                        out.buf, out.len, 0);
+                       strbuf_reset(&out);
                        continue;
                }
                else if (file->is_unmerged) {
-                       fprintf(options->file, "%s", line_prefix);
-                       show_name(options->file, prefix, name, len);
-                       fprintf(options->file, " Unmerged\n");
+                       strbuf_addf(&out, " %s%-*s |", prefix, len, name);
+                       strbuf_addstr(&out, " Unmerged\n");
+                       emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
+                                        out.buf, out.len, 0);
+                       strbuf_reset(&out);
                        continue;
                }
 
@@ -1904,14 +2525,16 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
                                add = total - del;
                        }
                }
-               fprintf(options->file, "%s", line_prefix);
-               show_name(options->file, prefix, name, len);
-               fprintf(options->file, " %*"PRIuMAX"%s",
+               strbuf_addf(&out, " %s%-*s |", prefix, len, name);
+               strbuf_addf(&out, " %*"PRIuMAX"%s",
                        number_width, added + deleted,
                        added + deleted ? " " : "");
-               show_graph(options->file, '+', add, add_c, reset);
-               show_graph(options->file, '-', del, del_c, reset);
-               fprintf(options->file, "\n");
+               show_graph(&out, '+', add, add_c, reset);
+               show_graph(&out, '-', del, del_c, reset);
+               strbuf_addch(&out, '\n');
+               emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
+                                out.buf, out.len, 0);
+               strbuf_reset(&out);
        }
 
        for (i = 0; i < data->nr; i++) {
@@ -1932,11 +2555,13 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
                if (i < count)
                        continue;
                if (!extra_shown)
-                       fprintf(options->file, "%s ...\n", line_prefix);
+                       emit_diff_symbol(options,
+                                        DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
+                                        NULL, 0, 0);
                extra_shown = 1;
        }
-       fprintf(options->file, "%s", line_prefix);
-       print_stat_summary(options->file, total_files, adds, dels);
+
+       print_stat_summary_inserts_deletes(options, total_files, adds, dels);
 }
 
 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
@@ -1948,7 +2573,7 @@ static void show_shortstats(struct diffstat_t *data, struct diff_options *option
 
        for (i = 0; i < data->nr; i++) {
                int added = data->files[i]->added;
-               int deleted= data->files[i]->deleted;
+               int deleted = data->files[i]->deleted;
 
                if (data->files[i]->is_unmerged ||
                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
@@ -1958,8 +2583,7 @@ static void show_shortstats(struct diffstat_t *data, struct diff_options *option
                        dels += deleted;
                }
        }
-       fprintf(options->file, "%s", diff_line_prefix(options));
-       print_stat_summary(options->file, total_files, adds, dels);
+       print_stat_summary_inserts_deletes(options, total_files, adds, dels);
 }
 
 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
@@ -2323,8 +2947,8 @@ static unsigned char *deflate_it(char *data,
        return deflated;
 }
 
-static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
-                                 const char *prefix)
+static void emit_binary_diff_body(struct diff_options *o,
+                                 mmfile_t *one, mmfile_t *two)
 {
        void *cp;
        void *delta;
@@ -2353,13 +2977,18 @@ static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
        }
 
        if (delta && delta_size < deflate_size) {
-               fprintf(file, "%sdelta %lu\n", prefix, orig_size);
+               char *s = xstrfmt("%lu", orig_size);
+               emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
+                                s, strlen(s), 0);
+               free(s);
                free(deflated);
                data = delta;
                data_size = delta_size;
-       }
-       else {
-               fprintf(file, "%sliteral %lu\n", prefix, two->size);
+       } else {
+               char *s = xstrfmt("%lu", two->size);
+               emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
+                                s, strlen(s), 0);
+               free(s);
                free(delta);
                data = deflated;
                data_size = deflate_size;
@@ -2368,8 +2997,9 @@ static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
        /* emit data encoded in base85 */
        cp = data;
        while (data_size) {
+               int len;
                int bytes = (52 < data_size) ? 52 : data_size;
-               char line[70];
+               char line[71];
                data_size -= bytes;
                if (bytes <= 26)
                        line[0] = bytes + 'A' - 1;
@@ -2377,20 +3007,24 @@ static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
                        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);
+
+               len = strlen(line);
+               line[len++] = '\n';
+               line[len] = '\0';
+
+               emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
+                                line, len, 0);
        }
-       fprintf(file, "%s\n", prefix);
+       emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
        free(data);
 }
 
-static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
-                            const char *prefix)
+static void emit_binary_diff(struct diff_options *o,
+                            mmfile_t *one, mmfile_t *two)
 {
-       fprintf(file, "%sGIT binary patch\n", prefix);
-       emit_binary_diff_body(file, one, two, prefix);
-       emit_binary_diff_body(file, two, one, prefix);
+       emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
+       emit_binary_diff_body(o, one, two);
+       emit_binary_diff_body(o, two, one);
 }
 
 int diff_filespec_is_binary(struct diff_filespec *one)
@@ -2467,24 +3101,16 @@ static void builtin_diff(const char *name_a,
        if (o->submodule_format == DIFF_SUBMODULE_LOG &&
            (!one->mode || S_ISGITLINK(one->mode)) &&
            (!two->mode || S_ISGITLINK(two->mode))) {
-               const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
-               const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
-               show_submodule_summary(o->file, one->path ? one->path : two->path,
-                               line_prefix,
+               show_submodule_summary(o, one->path ? one->path : two->path,
                                &one->oid, &two->oid,
-                               two->dirty_submodule,
-                               meta, del, add, reset);
+                               two->dirty_submodule);
                return;
        } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
                   (!one->mode || S_ISGITLINK(one->mode)) &&
                   (!two->mode || S_ISGITLINK(two->mode))) {
-               const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
-               const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
-               show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
-                               line_prefix,
+               show_submodule_inline_diff(o, one->path ? one->path : two->path,
                                &one->oid, &two->oid,
-                               two->dirty_submodule,
-                               meta, del, add, reset, o);
+                               two->dirty_submodule);
                return;
        }
 
@@ -2584,7 +3210,7 @@ static void builtin_diff(const char *name_a,
                emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
                strbuf_reset(&header);
                if (DIFF_OPT_TST(o, BINARY))
-                       emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
+                       emit_binary_diff(o, &mf1, &mf2);
                else {
                        strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
                                    diff_line_prefix(o), lbl[0], lbl[1]);
@@ -3519,6 +4145,8 @@ void diff_setup(struct diff_options *options)
                options->a_prefix = "a/";
                options->b_prefix = "b/";
        }
+
+       options->color_moved = diff_color_moved_default;
 }
 
 void diff_setup_done(struct diff_options *options)
@@ -3628,6 +4256,9 @@ void diff_setup_done(struct diff_options *options)
 
        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
                die(_("--follow requires exactly one pathspec"));
+
+       if (!options->use_color || external_diff())
+               options->color_moved = 0;
 }
 
 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
@@ -4052,7 +4683,19 @@ int diff_opt_parse(struct diff_options *options,
        }
        else if (!strcmp(arg, "--no-color"))
                options->use_color = 0;
-       else if (!strcmp(arg, "--color-words")) {
+       else if (!strcmp(arg, "--color-moved")) {
+               if (diff_color_moved_default)
+                       options->color_moved = diff_color_moved_default;
+               if (options->color_moved == COLOR_MOVED_NO)
+                       options->color_moved = COLOR_MOVED_DEFAULT;
+       } else if (!strcmp(arg, "--no-color-moved"))
+               options->color_moved = COLOR_MOVED_NO;
+       else if (skip_prefix(arg, "--color-moved=", &arg)) {
+               int cm = parse_color_moved(arg);
+               if (cm < 0)
+                       die("bad --color-moved argument: %s", arg);
+               options->color_moved = cm;
+       } else if (!strcmp(arg, "--color-words")) {
                options->use_color = 1;
                options->word_diff = DIFF_WORDS_COLOR;
        }
@@ -4582,67 +5225,76 @@ static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
        }
 }
 
-static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
+static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
 {
+       struct strbuf sb = STRBUF_INIT;
        if (fs->mode)
-               fprintf(file, " %s mode %06o ", newdelete, fs->mode);
+               strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
        else
-               fprintf(file, " %s ", newdelete);
-       write_name_quoted(fs->path, file, '\n');
-}
+               strbuf_addf(&sb, " %s ", newdelete);
 
+       quote_c_style(fs->path, &sb, NULL, 0);
+       strbuf_addch(&sb, '\n');
+       emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
+                        sb.buf, sb.len, 0);
+       strbuf_release(&sb);
+}
 
-static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
-               const char *line_prefix)
+static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
+               int show_name)
 {
        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
-               fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
-                       p->two->mode, show_name ? ' ' : '\n');
+               struct strbuf sb = STRBUF_INIT;
+               strbuf_addf(&sb, " mode change %06o => %06o",
+                           p->one->mode, p->two->mode);
                if (show_name) {
-                       write_name_quoted(p->two->path, file, '\n');
+                       strbuf_addch(&sb, ' ');
+                       quote_c_style(p->two->path, &sb, NULL, 0);
                }
+               emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
+                                sb.buf, sb.len, 0);
+               strbuf_release(&sb);
        }
 }
 
-static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
-                       const char *line_prefix)
+static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
+               struct diff_filepair *p)
 {
+       struct strbuf sb = STRBUF_INIT;
        char *names = pprint_rename(p->one->path, p->two->path);
-
-       fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
+       strbuf_addf(&sb, " %s %s (%d%%)\n",
+                       renamecopy, names, similarity_index(p));
        free(names);
-       show_mode_change(file, p, 0, line_prefix);
+       emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
+                                sb.buf, sb.len, 0);
+       show_mode_change(opt, p, 0);
 }
 
 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
 {
-       FILE *file = opt->file;
-       const char *line_prefix = diff_line_prefix(opt);
-
        switch(p->status) {
        case DIFF_STATUS_DELETED:
-               fputs(line_prefix, file);
-               show_file_mode_name(file, "delete", p->one);
+               show_file_mode_name(opt, "delete", p->one);
                break;
        case DIFF_STATUS_ADDED:
-               fputs(line_prefix, file);
-               show_file_mode_name(file, "create", p->two);
+               show_file_mode_name(opt, "create", p->two);
                break;
        case DIFF_STATUS_COPIED:
-               fputs(line_prefix, file);
-               show_rename_copy(file, "copy", p, line_prefix);
+               show_rename_copy(opt, "copy", p);
                break;
        case DIFF_STATUS_RENAMED:
-               fputs(line_prefix, file);
-               show_rename_copy(file, "rename", p, line_prefix);
+               show_rename_copy(opt, "rename", p);
                break;
        default:
                if (p->score) {
-                       fprintf(file, "%s rewrite ", line_prefix);
-                       write_name_quoted(p->two->path, file, ' ');
-                       fprintf(file, "(%d%%)\n", similarity_index(p));
+                       struct strbuf sb = STRBUF_INIT;
+                       strbuf_addstr(&sb, " rewrite ");
+                       quote_c_style(p->two->path, &sb, NULL, 0);
+                       strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
+                       emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
+                                        sb.buf, sb.len, 0);
                }
-               show_mode_change(file, p, !p->score, line_prefix);
+               show_mode_change(opt, p, !p->score);
                break;
        }
 }
@@ -4850,16 +5502,46 @@ void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
 {
        int i;
+       static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
        struct diff_queue_struct *q = &diff_queued_diff;
 
        if (WSEH_NEW & WS_RULE_MASK)
                die("BUG: WS rules bit mask overlaps with diff symbol flags");
 
+       if (o->color_moved)
+               o->emitted_symbols = &esm;
+
        for (i = 0; i < q->nr; i++) {
                struct diff_filepair *p = q->queue[i];
                if (check_pair_status(p))
                        diff_flush_patch(p, o);
        }
+
+       if (o->emitted_symbols) {
+               if (o->color_moved) {
+                       struct hashmap add_lines, del_lines;
+
+                       hashmap_init(&del_lines,
+                                    (hashmap_cmp_fn)moved_entry_cmp, o, 0);
+                       hashmap_init(&add_lines,
+                                    (hashmap_cmp_fn)moved_entry_cmp, o, 0);
+
+                       add_lines_to_move_detection(o, &add_lines, &del_lines);
+                       mark_color_as_moved(o, &add_lines, &del_lines);
+                       if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
+                               dim_moved_lines(o);
+
+                       hashmap_free(&add_lines, 0);
+                       hashmap_free(&del_lines, 0);
+               }
+
+               for (i = 0; i < esm.nr; i++)
+                       emit_diff_symbol_from_struct(o, &esm.buf[i]);
+
+               for (i = 0; i < esm.nr; i++)
+                       free((void *)esm.buf[i].line);
+       }
+       esm.nr = 0;
 }
 
 void diff_flush(struct diff_options *options)
@@ -4934,6 +5616,7 @@ void diff_flush(struct diff_options *options)
                        fclose(options->file);
                options->file = xfopen("/dev/null", "w");
                options->close_file = 1;
+               options->color_moved = 0;
                for (i = 0; i < q->nr; i++) {
                        struct diff_filepair *p = q->queue[i];
                        if (check_pair_status(p))
@@ -4946,10 +5629,10 @@ void diff_flush(struct diff_options *options)
        if (output_format & DIFF_FORMAT_PATCH) {
                if (separator) {
                        emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
-                       if (options->stat_sep) {
+                       if (options->stat_sep)
                                /* attach patch instead of inline */
-                               fputs(options->stat_sep, options->file);
-                       }
+                               emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
+                                                NULL, 0, 0);
                }
 
                diff_flush_patch_all_file_pairs(options);