Merge branch 'jc/diff'

* jc/diff:
  Libified diff-index: backward compatibility fix.
  Libify diff-index.
  Libify diff-files.

1 files changed, 256 insertions, 1707 deletions

diff --git a/diff-lib.c b/diff-lib.c
index 13b216f273..2183b41b03 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -1,1795 +1,344 @@
 /*
  * Copyright (C) 2005 Junio C Hamano
  */
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <signal.h>
 #include "cache.h"
 #include "quote.h"
+#include "commit.h"
 #include "diff.h"
 #include "diffcore.h"
-#include "xdiff-interface.h"
+#include "revision.h"
 
-static int use_size_cache;
-
-int diff_rename_limit_default = -1;
-
-int git_diff_config(const char *var, const char *value)
-{
-	if (!strcmp(var, "diff.renamelimit")) {
-		diff_rename_limit_default = git_config_int(var, value);
-		return 0;
-	}
-
-	return git_default_config(var, value);
-}
-
-static char *quote_one(const char *str)
-{
-	int needlen;
-	char *xp;
-
-	if (!str)
-		return NULL;
-	needlen = quote_c_style(str, NULL, NULL, 0);
-	if (!needlen)
-		return strdup(str);
-	xp = xmalloc(needlen + 1);
-	quote_c_style(str, xp, NULL, 0);
-	return xp;
-}
-
-static char *quote_two(const char *one, const char *two)
-{
-	int need_one = quote_c_style(one, NULL, NULL, 1);
-	int need_two = quote_c_style(two, NULL, NULL, 1);
-	char *xp;
-
-	if (need_one + need_two) {
-		if (!need_one) need_one = strlen(one);
-		if (!need_two) need_one = strlen(two);
-
-		xp = xmalloc(need_one + need_two + 3);
-		xp[0] = '"';
-		quote_c_style(one, xp + 1, NULL, 1);
-		quote_c_style(two, xp + need_one + 1, NULL, 1);
-		strcpy(xp + need_one + need_two + 1, "\"");
-		return xp;
-	}
-	need_one = strlen(one);
-	need_two = strlen(two);
-	xp = xmalloc(need_one + need_two + 1);
-	strcpy(xp, one);
-	strcpy(xp + need_one, two);
-	return xp;
-}
-
-static const char *external_diff(void)
-{
-	static const char *external_diff_cmd = NULL;
-	static int done_preparing = 0;
-
-	if (done_preparing)
-		return external_diff_cmd;
-	external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
-	done_preparing = 1;
-	return external_diff_cmd;
-}
-
-#define TEMPFILE_PATH_LEN		50
-
-static struct diff_tempfile {
-	const char *name; /* filename external diff should read from */
-	char hex[41];
-	char mode[10];
-	char tmp_path[TEMPFILE_PATH_LEN];
-} diff_temp[2];
-
-static int count_lines(const char *data, int size)
-{
-	int count, ch, completely_empty = 1, nl_just_seen = 0;
-	count = 0;
-	while (0 < size--) {
-		ch = *data++;
-		if (ch == '\n') {
-			count++;
-			nl_just_seen = 1;
-			completely_empty = 0;
-		}
-		else {
-			nl_just_seen = 0;
-			completely_empty = 0;
-		}
-	}
-	if (completely_empty)
-		return 0;
-	if (!nl_just_seen)
-		count++; /* no trailing newline */
-	return count;
-}
-
-static void print_line_count(int count)
-{
-	switch (count) {
-	case 0:
-		printf("0,0");
-		break;
-	case 1:
-		printf("1");
-		break;
-	default:
-		printf("1,%d", count);
-		break;
-	}
-}
-
-static void copy_file(int prefix, const char *data, int size)
-{
-	int ch, nl_just_seen = 1;
-	while (0 < size--) {
-		ch = *data++;
-		if (nl_just_seen)
-			putchar(prefix);
-		putchar(ch);
-		if (ch == '\n')
-			nl_just_seen = 1;
-		else
-			nl_just_seen = 0;
-	}
-	if (!nl_just_seen)
-		printf("\n\\ No newline at end of file\n");
-}
+/*
+ * diff-files
+ */
 
-static void emit_rewrite_diff(const char *name_a,
-			      const char *name_b,
-			      struct diff_filespec *one,
-			      struct diff_filespec *two)
+int run_diff_files(struct rev_info *revs, int silent_on_removed)
 {
-	int lc_a, lc_b;
-	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\n+++ %s\n@@ -", name_a, name_b);
-	print_line_count(lc_a);
-	printf(" +");
-	print_line_count(lc_b);
-	printf(" @@\n");
-	if (lc_a)
-		copy_file('-', one->data, one->size);
-	if (lc_b)
-		copy_file('+', two->data, two->size);
-}
+	int entries, i;
+	int diff_unmerged_stage = revs->max_count;
 
-static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
-{
-	if (!DIFF_FILE_VALID(one)) {
-		mf->ptr = ""; /* does not matter */
-		mf->size = 0;
-		return 0;
-	}
-	else if (diff_populate_filespec(one, 0))
+	if (diff_unmerged_stage < 0)
+		diff_unmerged_stage = 2;
+	entries = read_cache();
+	if (entries < 0) {
+		perror("read_cache");
 		return -1;
-	mf->ptr = one->data;
-	mf->size = one->size;
-	return 0;
-}
-
-struct emit_callback {
-	const char **label_path;
-};
-
-static int fn_out(void *priv, mmbuffer_t *mb, int nbuf)
-{
-	int i;
-	struct emit_callback *ecbdata = priv;
-
-	if (ecbdata->label_path[0]) {
-		printf("--- %s\n", ecbdata->label_path[0]);
-		printf("+++ %s\n", ecbdata->label_path[1]);
-		ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 	}
-	for (i = 0; i < nbuf; i++)
-		if (!fwrite(mb[i].ptr, mb[i].size, 1, stdout))
-			return -1;
-	return 0;
-}
-
-static char *pprint_rename(const char *a, const char *b)
-{
-	const char *old = a;
-	const char *new = b;
-	char *name = NULL;
-	int pfx_length, sfx_length;
-	int len_a = strlen(a);
-	int len_b = strlen(b);
-
-	/* Find common prefix */
-	pfx_length = 0;
-	while (*old && *new && *old == *new) {
-		if (*old == '/')
-			pfx_length = old - a + 1;
-		old++;
-		new++;
-	}
-
-	/* Find common suffix */
-	old = a + len_a;
-	new = b + len_b;
-	sfx_length = 0;
-	while (a <= old && b <= new && *old == *new) {
-		if (*old == '/')
-			sfx_length = len_a - (old - a);
-		old--;
-		new--;
-	}
-
-	/*
-	 * pfx{mid-a => mid-b}sfx
-	 * {pfx-a => pfx-b}sfx
-	 * pfx{sfx-a => sfx-b}
-	 * name-a => name-b
-	 */
-	if (pfx_length + sfx_length) {
-		name = xmalloc(len_a + len_b - pfx_length - sfx_length + 7);
-		sprintf(name, "%.*s{%.*s => %.*s}%s",
-			pfx_length, a,
-			len_a - pfx_length - sfx_length, a + pfx_length,
-			len_b - pfx_length - sfx_length, b + pfx_length,
-			a + len_a - sfx_length);
-	}
-	else {
-		name = xmalloc(len_a + len_b + 5);
-		sprintf(name, "%s => %s", a, b);
-	}
-	return name;
-}
-
-struct diffstat_t {
-	struct xdiff_emit_state xm;
-
-	int nr;
-	int alloc;
-	struct diffstat_file {
-		char *name;
-		unsigned is_unmerged:1;
-		unsigned is_binary:1;
-		unsigned is_renamed:1;
-		unsigned int added, deleted;
-	} **files;
-};
-
-static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
-					  const char *name_a,
-					  const char *name_b)
-{
-	struct diffstat_file *x;
-	x = xcalloc(sizeof (*x), 1);
-	if (diffstat->nr == diffstat->alloc) {
-		diffstat->alloc = alloc_nr(diffstat->alloc);
-		diffstat->files = xrealloc(diffstat->files,
-				diffstat->alloc * sizeof(x));
-	}
-	diffstat->files[diffstat->nr++] = x;
-	if (name_b) {
-		x->name = pprint_rename(name_a, name_b);
-		x->is_renamed = 1;
-	}
-	else
-		x->name = strdup(name_a);
-	return x;
-}
-
-static void diffstat_consume(void *priv, char *line, unsigned long len)
-{
-	struct diffstat_t *diffstat = priv;
-	struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
-
-	if (line[0] == '+')
-		x->added++;
-	else if (line[0] == '-')
-		x->deleted++;
-}
-
-static const char pluses[] = "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
-static const char minuses[]= "----------------------------------------------------------------------";
-
-static void show_stats(struct diffstat_t* data)
-{
-	char *prefix = "";
-	int i, len, add, del, total, adds = 0, dels = 0;
-	int max, max_change = 0, max_len = 0;
-	int total_files = data->nr;
-
-	if (data->nr == 0)
-		return;
-
-	for (i = 0; i < data->nr; i++) {
-		struct diffstat_file *file = data->files[i];
-
-		len = strlen(file->name);
-		if (max_len < len)
-			max_len = len;
+	for (i = 0; i < entries; i++) {
+		struct stat st;
+		unsigned int oldmode, newmode;
+		struct cache_entry *ce = active_cache[i];
+		int changed;
 
-		if (file->is_binary || file->is_unmerged)
+		if (!ce_path_match(ce, revs->prune_data))
 			continue;
-		if (max_change < file->added + file->deleted)
-			max_change = file->added + file->deleted;
-	}
 
-	for (i = 0; i < data->nr; i++) {
-		char *name = data->files[i]->name;
-		int added = data->files[i]->added;
-		int deleted = data->files[i]->deleted;
+		if (ce_stage(ce)) {
+			struct {
+				struct combine_diff_path p;
+				struct combine_diff_parent filler[5];
+			} combine;
+			int num_compare_stages = 0;
+
+			combine.p.next = NULL;
+			combine.p.len = ce_namelen(ce);
+			combine.p.path = xmalloc(combine.p.len + 1);
+			memcpy(combine.p.path, ce->name, combine.p.len);
+			combine.p.path[combine.p.len] = 0;
+			combine.p.mode = 0;
+			memset(combine.p.sha1, 0, 20);
+			memset(&combine.p.parent[0], 0,
+			       sizeof(combine.filler));
+
+			while (i < entries) {
+				struct cache_entry *nce = active_cache[i];
+				int stage;
+
+				if (strcmp(ce->name, nce->name))
+					break;
+
+				/* Stage #2 (ours) is the first parent,
+				 * stage #3 (theirs) is the second.
+				 */
+				stage = ce_stage(nce);
+				if (2 <= stage) {
+					int mode = ntohl(nce->ce_mode);
+					num_compare_stages++;
+					memcpy(combine.p.parent[stage-2].sha1,
+					       nce->sha1, 20);
+					combine.p.parent[stage-2].mode =
+						canon_mode(mode);
+					combine.p.parent[stage-2].status =
+						DIFF_STATUS_MODIFIED;
+				}
+
+				/* diff against the proper unmerged stage */
+				if (stage == diff_unmerged_stage)
+					ce = nce;
+				i++;
+			}
+			/*
+			 * Compensate for loop update
+			 */
+			i--;
 
-		if (0 < (len = quote_c_style(name, NULL, NULL, 0))) {
-			char *qname = xmalloc(len + 1);
-			quote_c_style(name, qname, NULL, 0);
-			free(name);
-			data->files[i]->name = name = qname;
-		}
+			if (revs->combine_merges && num_compare_stages == 2) {
+				show_combined_diff(&combine.p, 2,
+						   revs->dense_combined_merges,
+						   revs);
+				free(combine.p.path);
+				continue;
+			}
+			free(combine.p.path);
 
-		/*
-		 * "scale" the filename
-		 */
-		len = strlen(name);
-		max = max_len;
-		if (max > 50)
-			max = 50;
-		if (len > max) {
-			char *slash;
-			prefix = "...";
-			max -= 3;
-			name += len - max;
-			slash = strchr(name, '/');
-			if (slash)
-				name = slash;
+			/*
+			 * Show the diff for the 'ce' if we found the one
+			 * from the desired stage.
+			 */
+			diff_unmerge(&revs->diffopt, ce->name);
+			if (ce_stage(ce) != diff_unmerged_stage)
+				continue;
 		}
-		len = max;
 
-		/*
-		 * scale the add/delete
-		 */
-		max = max_change;
-		if (max + len > 70)
-			max = 70 - len;
-
-		if (data->files[i]->is_binary) {
-			printf(" %s%-*s |  Bin\n", prefix, len, name);
-			goto free_diffstat_file;
-		}
-		else if (data->files[i]->is_unmerged) {
-			printf(" %s%-*s |  Unmerged\n", prefix, len, name);
-			goto free_diffstat_file;
-		}
-		else if (!data->files[i]->is_renamed &&
-			 (added + deleted == 0)) {
-			total_files--;
-			goto free_diffstat_file;
+		if (lstat(ce->name, &st) < 0) {
+			if (errno != ENOENT && errno != ENOTDIR) {
+				perror(ce->name);
+				continue;
+			}
+			if (silent_on_removed)
+				continue;
+			diff_addremove(&revs->diffopt, '-', ntohl(ce->ce_mode),
+				       ce->sha1, ce->name, NULL);
+			continue;
 		}
+		changed = ce_match_stat(ce, &st, 0);
+		if (!changed && !revs->diffopt.find_copies_harder)
+			continue;
+		oldmode = ntohl(ce->ce_mode);
 
-		add = added;
-		del = deleted;
-		total = add + del;
-		adds += add;
-		dels += del;
+		newmode = canon_mode(st.st_mode);
+		if (!trust_executable_bit &&
+		    S_ISREG(newmode) && S_ISREG(oldmode) &&
+		    ((newmode ^ oldmode) == 0111))
+			newmode = oldmode;
+		diff_change(&revs->diffopt, oldmode, newmode,
+			    ce->sha1, (changed ? null_sha1 : ce->sha1),
+			    ce->name, NULL);
 
-		if (max_change > 0) {
-			total = (total * max + max_change / 2) / max_change;
-			add = (add * max + max_change / 2) / max_change;
-			del = total - add;
-		}
-		printf(" %s%-*s |%5d %.*s%.*s\n", prefix,
-				len, name, added + deleted,
-				add, pluses, del, minuses);
-	free_diffstat_file:
-		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);
-}
-
-#define FIRST_FEW_BYTES 8000
-static int mmfile_is_binary(mmfile_t *mf)
-{
-	long sz = mf->size;
-	if (FIRST_FEW_BYTES < sz)
-		sz = FIRST_FEW_BYTES;
-	if (memchr(mf->ptr, 0, sz))
-		return 1;
+	diffcore_std(&revs->diffopt);
+	diff_flush(&revs->diffopt);
 	return 0;
 }
 
-static void builtin_diff(const char *name_a,
-			 const char *name_b,
-			 struct diff_filespec *one,
-			 struct diff_filespec *two,
-			 const char *xfrm_msg,
-			 int complete_rewrite)
-{
-	mmfile_t mf1, mf2;
-	const char *lbl[2];
-	char *a_one, *b_two;
-
-	a_one = quote_two("a/", name_a);
-	b_two = quote_two("b/", name_b);
-	lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
-	lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
-	printf("diff --git %s %s\n", a_one, b_two);
-	if (lbl[0][0] == '/') {
-		/* /dev/null */
-		printf("new file mode %06o\n", two->mode);
-		if (xfrm_msg && xfrm_msg[0])
-			puts(xfrm_msg);
-	}
-	else if (lbl[1][0] == '/') {
-		printf("deleted file mode %06o\n", one->mode);
-		if (xfrm_msg && xfrm_msg[0])
-			puts(xfrm_msg);
-	}
-	else {
-		if (one->mode != two->mode) {
-			printf("old mode %06o\n", one->mode);
-			printf("new mode %06o\n", two->mode);
-		}
-		if (xfrm_msg && xfrm_msg[0])
-			puts(xfrm_msg);
-		/*
-		 * we do not run diff between different kind
-		 * of objects.
-		 */
-		if ((one->mode ^ two->mode) & S_IFMT)
-			goto free_ab_and_return;
-		if (complete_rewrite) {
-			emit_rewrite_diff(name_a, name_b, one, two);
-			goto free_ab_and_return;
-		}
-	}
-
-	if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
-		die("unable to read files to diff");
-
-	if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))
-		printf("Binary files %s and %s differ\n", lbl[0], lbl[1]);
-	else {
-		/* Crazy xdl interfaces.. */
-		const char *diffopts = getenv("GIT_DIFF_OPTS");
-		xpparam_t xpp;
-		xdemitconf_t xecfg;
-		xdemitcb_t ecb;
-		struct emit_callback ecbdata;
-
-		ecbdata.label_path = lbl;
-		xpp.flags = XDF_NEED_MINIMAL;
-		xecfg.ctxlen = 3;
-		xecfg.flags = XDL_EMIT_FUNCNAMES;
-		if (!diffopts)
-			;
-		else if (!strncmp(diffopts, "--unified=", 10))
-			xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
-		else if (!strncmp(diffopts, "-u", 2))
-			xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
-		ecb.outf = fn_out;
-		ecb.priv = &ecbdata;
-		xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
-	}
-
- free_ab_and_return:
-	free(a_one);
-	free(b_two);
-	return;
-}
-
-static void builtin_diffstat(const char *name_a, const char *name_b,
-			     struct diff_filespec *one,
-			     struct diff_filespec *two,
-			     struct diffstat_t *diffstat)
-{
-	mmfile_t mf1, mf2;
-	struct diffstat_file *data;
-
-	data = diffstat_add(diffstat, name_a, name_b);
-
-	if (!one || !two) {
-		data->is_unmerged = 1;
-		return;
-	}
-
-	if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
-		die("unable to read files to diff");
-
-	if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))
-		data->is_binary = 1;
-	else {
-		/* Crazy xdl interfaces.. */
-		xpparam_t xpp;
-		xdemitconf_t xecfg;
-		xdemitcb_t ecb;
-
-		xpp.flags = XDF_NEED_MINIMAL;
-		xecfg.ctxlen = 0;
-		xecfg.flags = 0;
-		ecb.outf = xdiff_outf;
-		ecb.priv = diffstat;
-		xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
-	}
-}
-
-struct diff_filespec *alloc_filespec(const char *path)
-{
-	int namelen = strlen(path);
-	struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
-
-	memset(spec, 0, sizeof(*spec));
-	spec->path = (char *)(spec + 1);
-	memcpy(spec->path, path, namelen+1);
-	return spec;
-}
-
-void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
-		   unsigned short mode)
-{
-	if (mode) {
-		spec->mode = canon_mode(mode);
-		memcpy(spec->sha1, sha1, 20);
-		spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
-	}
-}
-
 /*
- * Given a name and sha1 pair, if the dircache tells us the file in
- * the work tree has that object contents, return true, so that
- * prepare_temp_file() does not have to inflate and extract.
+ * diff-index
  */
-static int work_tree_matches(const char *name, const unsigned char *sha1)
-{
-	struct cache_entry *ce;
-	struct stat st;
-	int pos, len;
-
-	/* We do not read the cache ourselves here, because the
-	 * benchmark with my previous version that always reads cache
-	 * shows that it makes things worse for diff-tree comparing
-	 * two linux-2.6 kernel trees in an already checked out work
-	 * tree.  This is because most diff-tree comparisons deal with
-	 * only a small number of files, while reading the cache is
-	 * expensive for a large project, and its cost outweighs the
-	 * savings we get by not inflating the object to a temporary
-	 * file.  Practically, this code only helps when we are used
-	 * by diff-cache --cached, which does read the cache before
-	 * calling us.
-	 */
-	if (!active_cache)
-		return 0;
 
-	len = strlen(name);
-	pos = cache_name_pos(name, len);
-	if (pos < 0)
-		return 0;
-	ce = active_cache[pos];
-	if ((lstat(name, &st) < 0) ||
-	    !S_ISREG(st.st_mode) || /* careful! */
-	    ce_match_stat(ce, &st, 0) ||
-	    memcmp(sha1, ce->sha1, 20))
-		return 0;
-	/* we return 1 only when we can stat, it is a regular file,
-	 * stat information matches, and sha1 recorded in the cache
-	 * matches.  I.e. we know the file in the work tree really is
-	 * the same as the <name, sha1> pair.
-	 */
-	return 1;
-}
-
-static struct sha1_size_cache {
-	unsigned char sha1[20];
-	unsigned long size;
-} **sha1_size_cache;
-static int sha1_size_cache_nr, sha1_size_cache_alloc;
-
-static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
-						 int find_only,
-						 unsigned long size)
+/* A file entry went away or appeared */
+static void diff_index_show_file(struct rev_info *revs,
+				 const char *prefix,
+				 struct cache_entry *ce,
+				 unsigned char *sha1, unsigned int mode)
 {
-	int first, last;
-	struct sha1_size_cache *e;
-
-	first = 0;
-	last = sha1_size_cache_nr;
-	while (last > first) {
-		int cmp, next = (last + first) >> 1;
-		e = sha1_size_cache[next];
-		cmp = memcmp(e->sha1, sha1, 20);
-		if (!cmp)
-			return e;
-		if (cmp < 0) {
-			last = next;
-			continue;
-		}
-		first = next+1;
-	}
-	/* not found */
-	if (find_only)
-		return NULL;
-	/* insert to make it at "first" */
-	if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
-		sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
-		sha1_size_cache = xrealloc(sha1_size_cache,
-					   sha1_size_cache_alloc *
-					   sizeof(*sha1_size_cache));
-	}
-	sha1_size_cache_nr++;
-	if (first < sha1_size_cache_nr)
-		memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
-			(sha1_size_cache_nr - first - 1) *
-			sizeof(*sha1_size_cache));
-	e = xmalloc(sizeof(struct sha1_size_cache));
-	sha1_size_cache[first] = e;
-	memcpy(e->sha1, sha1, 20);
-	e->size = size;
-	return e;
+	diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
+		       sha1, ce->name, NULL);
 }
 
-/*
- * While doing rename detection and pickaxe operation, we may need to
- * grab the data for the blob (or file) for our own in-core comparison.
- * diff_filespec has data and size fields for this purpose.
- */
-int diff_populate_filespec(struct diff_filespec *s, int size_only)
+static int get_stat_data(struct cache_entry *ce,
+			 unsigned char **sha1p,
+			 unsigned int *modep,
+			 int cached, int match_missing)
 {
-	int err = 0;
-	if (!DIFF_FILE_VALID(s))
-		die("internal error: asking to populate invalid file.");
-	if (S_ISDIR(s->mode))
-		return -1;
-
-	if (!use_size_cache)
-		size_only = 0;
+	unsigned char *sha1 = ce->sha1;
+	unsigned int mode = ce->ce_mode;
 
-	if (s->data)
-		return err;
-	if (!s->sha1_valid ||
-	    work_tree_matches(s->path, s->sha1)) {
+	if (!cached) {
+		static unsigned char no_sha1[20];
+		int changed;
 		struct stat st;
-		int fd;
-		if (lstat(s->path, &st) < 0) {
-			if (errno == ENOENT) {
-			err_empty:
-				err = -1;
-			empty:
-				s->data = "";
-				s->size = 0;
-				return err;
-			}
-		}
-		s->size = st.st_size;
-		if (!s->size)
-			goto empty;
-		if (size_only)
-			return 0;
-		if (S_ISLNK(st.st_mode)) {
-			int ret;
-			s->data = xmalloc(s->size);
-			s->should_free = 1;
-			ret = readlink(s->path, s->data, s->size);
-			if (ret < 0) {
-				free(s->data);
-				goto err_empty;
-			}
-			return 0;
-		}
-		fd = open(s->path, O_RDONLY);
-		if (fd < 0)
-			goto err_empty;
-		s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
-		close(fd);
-		if (s->data == MAP_FAILED)
-			goto err_empty;
-		s->should_munmap = 1;
-	}
-	else {
-		char type[20];
-		struct sha1_size_cache *e;
-
-		if (size_only) {
-			e = locate_size_cache(s->sha1, 1, 0);
-			if (e) {
-				s->size = e->size;
+		if (lstat(ce->name, &st) < 0) {
+			if (errno == ENOENT && match_missing) {
+				*sha1p = sha1;
+				*modep = mode;
 				return 0;
 			}
-			if (!sha1_object_info(s->sha1, type, &s->size))
-				locate_size_cache(s->sha1, 0, s->size);
-		}
-		else {
-			s->data = read_sha1_file(s->sha1, type, &s->size);
-			s->should_free = 1;
-		}
-	}
-	return 0;
-}
-
-void diff_free_filespec_data(struct diff_filespec *s)
-{
-	if (s->should_free)
-		free(s->data);
-	else if (s->should_munmap)
-		munmap(s->data, s->size);
-	s->should_free = s->should_munmap = 0;
-	s->data = NULL;
-	free(s->cnt_data);
-	s->cnt_data = NULL;
-}
-
-static void prep_temp_blob(struct diff_tempfile *temp,
-			   void *blob,
-			   unsigned long size,
-			   const unsigned char *sha1,
-			   int mode)
-{
-	int fd;
-
-	fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
-	if (fd < 0)
-		die("unable to create temp-file");
-	if (write(fd, blob, size) != size)
-		die("unable to write temp-file");
-	close(fd);
-	temp->name = temp->tmp_path;
-	strcpy(temp->hex, sha1_to_hex(sha1));
-	temp->hex[40] = 0;
-	sprintf(temp->mode, "%06o", mode);
-}
-
-static void prepare_temp_file(const char *name,
-			      struct diff_tempfile *temp,
-			      struct diff_filespec *one)
-{
-	if (!DIFF_FILE_VALID(one)) {
-	not_a_valid_file:
-		/* A '-' entry produces this for file-2, and
-		 * a '+' entry produces this for file-1.
-		 */
-		temp->name = "/dev/null";
-		strcpy(temp->hex, ".");
-		strcpy(temp->mode, ".");
-		return;
-	}
-
-	if (!one->sha1_valid ||
-	    work_tree_matches(name, one->sha1)) {
-		struct stat st;
-		if (lstat(name, &st) < 0) {
-			if (errno == ENOENT)
-				goto not_a_valid_file;
-			die("stat(%s): %s", name, strerror(errno));
-		}
-		if (S_ISLNK(st.st_mode)) {
-			int ret;
-			char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
-			if (sizeof(buf) <= st.st_size)
-				die("symlink too long: %s", name);
-			ret = readlink(name, buf, st.st_size);
-			if (ret < 0)
-				die("readlink(%s)", name);
-			prep_temp_blob(temp, buf, st.st_size,
-				       (one->sha1_valid ?
-					one->sha1 : null_sha1),
-				       (one->sha1_valid ?
-					one->mode : S_IFLNK));
+			return -1;
 		}
-		else {
-			/* we can borrow from the file in the work tree */
-			temp->name = name;
-			if (!one->sha1_valid)
-				strcpy(temp->hex, sha1_to_hex(null_sha1));
-			else
-				strcpy(temp->hex, sha1_to_hex(one->sha1));
-			/* Even though we may sometimes borrow the
-			 * contents from the work tree, we always want
-			 * one->mode.  mode is trustworthy even when
-			 * !(one->sha1_valid), as long as
-			 * DIFF_FILE_VALID(one).
-			 */
-			sprintf(temp->mode, "%06o", one->mode);
+		changed = ce_match_stat(ce, &st, 0);
+		if (changed) {
+			mode = create_ce_mode(st.st_mode);
+			if (!trust_executable_bit && S_ISREG(st.st_mode))
+				mode = ce->ce_mode;
+			sha1 = no_sha1;
 		}
-		return;
 	}
-	else {
-		if (diff_populate_filespec(one, 0))
-			die("cannot read data blob for %s", one->path);
-		prep_temp_blob(temp, one->data, one->size,
-			       one->sha1, one->mode);
-	}
-}
 
-static void remove_tempfile(void)
-{
-	int i;
-
-	for (i = 0; i < 2; i++)
-		if (diff_temp[i].name == diff_temp[i].tmp_path) {
-			unlink(diff_temp[i].name);
-			diff_temp[i].name = NULL;
-		}
-}
-
-static void remove_tempfile_on_signal(int signo)
-{
-	remove_tempfile();
-	signal(SIGINT, SIG_DFL);
-	raise(signo);
+	*sha1p = sha1;
+	*modep = mode;
+	return 0;
 }
 
-static int spawn_prog(const char *pgm, const char **arg)
+static void show_new_file(struct rev_info *revs,
+			  struct cache_entry *new,
+			  int cached, int match_missing)
 {
-	pid_t pid;
-	int status;
-
-	fflush(NULL);
-	pid = fork();
-	if (pid < 0)
-		die("unable to fork");
-	if (!pid) {
-		execvp(pgm, (char *const*) arg);
-		exit(255);
-	}
-
-	while (waitpid(pid, &status, 0) < 0) {
-		if (errno == EINTR)
-			continue;
-		return -1;
-	}
+	unsigned char *sha1;
+	unsigned int mode;
 
-	/* Earlier we did not check the exit status because
-	 * diff exits non-zero if files are different, and
-	 * we are not interested in knowing that.  It was a
-	 * mistake which made it harder to quit a diff-*
-	 * session that uses the git-apply-patch-script as
-	 * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
-	 * should also exit non-zero only when it wants to
-	 * abort the entire diff-* session.
+	/* New file in the index: it might actually be different in
+	 * the working copy.
 	 */
-	if (WIFEXITED(status) && !WEXITSTATUS(status))
-		return 0;
-	return -1;
-}
-
-/* An external diff command takes:
- *
- * diff-cmd name infile1 infile1-sha1 infile1-mode \
- *               infile2 infile2-sha1 infile2-mode [ rename-to ]
- *
- */
-static void run_external_diff(const char *pgm,
-			      const char *name,
-			      const char *other,
-			      struct diff_filespec *one,
-			      struct diff_filespec *two,
-			      const char *xfrm_msg,
-			      int complete_rewrite)
-{
-	const char *spawn_arg[10];
-	struct diff_tempfile *temp = diff_temp;
-	int retval;
-	static int atexit_asked = 0;
-	const char *othername;
-	const char **arg = &spawn_arg[0];
-
-	othername = (other? other : name);
-	if (one && two) {
-		prepare_temp_file(name, &temp[0], one);
-		prepare_temp_file(othername, &temp[1], two);
-		if (! atexit_asked &&
-		    (temp[0].name == temp[0].tmp_path ||
-		     temp[1].name == temp[1].tmp_path)) {
-			atexit_asked = 1;
-			atexit(remove_tempfile);
-		}
-		signal(SIGINT, remove_tempfile_on_signal);
-	}
-
-	if (one && two) {
-		*arg++ = pgm;
-		*arg++ = name;
-		*arg++ = temp[0].name;
-		*arg++ = temp[0].hex;
-		*arg++ = temp[0].mode;
-		*arg++ = temp[1].name;
-		*arg++ = temp[1].hex;
-		*arg++ = temp[1].mode;
-		if (other) {
-			*arg++ = other;
-			*arg++ = xfrm_msg;
-		}
-	} else {
-		*arg++ = pgm;
-		*arg++ = name;
-	}
-	*arg = NULL;
-	retval = spawn_prog(pgm, spawn_arg);
-	remove_tempfile();
-	if (retval) {
-		fprintf(stderr, "external diff died, stopping at %s.\n", name);
-		exit(1);
-	}
-}
-
-static void run_diff_cmd(const char *pgm,
-			 const char *name,
-			 const char *other,
-			 struct diff_filespec *one,
-			 struct diff_filespec *two,
-			 const char *xfrm_msg,
-			 int complete_rewrite)
-{
-	if (pgm) {
-		run_external_diff(pgm, name, other, one, two, xfrm_msg,
-				  complete_rewrite);
+	if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
 		return;
-	}
-	if (one && two)
-		builtin_diff(name, other ? other : name,
-			     one, two, xfrm_msg, complete_rewrite);
-	else
-		printf("* Unmerged path %s\n", name);
-}
 
-static void diff_fill_sha1_info(struct diff_filespec *one)
-{
-	if (DIFF_FILE_VALID(one)) {
-		if (!one->sha1_valid) {
-			struct stat st;
-			if (lstat(one->path, &st) < 0)
-				die("stat %s", one->path);
-			if (index_path(one->sha1, one->path, &st, 0))
-				die("cannot hash %s\n", one->path);
-		}
-	}
-	else
-		memset(one->sha1, 0, 20);
+	diff_index_show_file(revs, "+", new, sha1, mode);
 }
 
-static void run_diff(struct diff_filepair *p, struct diff_options *o)
+static int show_modified(struct rev_info *revs,
+			 struct cache_entry *old,
+			 struct cache_entry *new,
+			 int report_missing,
+			 int cached, int match_missing)
 {
-	const char *pgm = external_diff();
-	char msg[PATH_MAX*2+300], *xfrm_msg;
-	struct diff_filespec *one;
-	struct diff_filespec *two;
-	const char *name;
-	const char *other;
-	char *name_munged, *other_munged;
-	int complete_rewrite = 0;
-	int len;
-
-	if (DIFF_PAIR_UNMERGED(p)) {
-		/* unmerged */
-		run_diff_cmd(pgm, p->one->path, NULL, NULL, NULL, NULL, 0);
-		return;
-	}
-
-	name = p->one->path;
-	other = (strcmp(name, p->two->path) ? p->two->path : NULL);
-	name_munged = quote_one(name);
-	other_munged = quote_one(other);
-	one = p->one; two = p->two;
-
-	diff_fill_sha1_info(one);
-	diff_fill_sha1_info(two);
-
-	len = 0;
-	switch (p->status) {
-	case DIFF_STATUS_COPIED:
-		len += snprintf(msg + len, sizeof(msg) - len,
-				"similarity index %d%%\n"
-				"copy from %s\n"
-				"copy to %s\n",
-				(int)(0.5 + p->score * 100.0/MAX_SCORE),
-				name_munged, other_munged);
-		break;
-	case DIFF_STATUS_RENAMED:
-		len += snprintf(msg + len, sizeof(msg) - len,
-				"similarity index %d%%\n"
-				"rename from %s\n"
-				"rename to %s\n",
-				(int)(0.5 + p->score * 100.0/MAX_SCORE),
-				name_munged, other_munged);
-		break;
-	case DIFF_STATUS_MODIFIED:
-		if (p->score) {
-			len += snprintf(msg + len, sizeof(msg) - len,
-					"dissimilarity index %d%%\n",
-					(int)(0.5 + p->score *
-					      100.0/MAX_SCORE));
-			complete_rewrite = 1;
-			break;
-		}
-		/* fallthru */
-	default:
-		/* nothing */
-		;
-	}
-
-	if (memcmp(one->sha1, two->sha1, 20)) {
-		char one_sha1[41];
-		int abbrev = o->full_index ? 40 : DEFAULT_ABBREV;
-		memcpy(one_sha1, sha1_to_hex(one->sha1), 41);
-
-		len += snprintf(msg + len, sizeof(msg) - len,
-				"index %.*s..%.*s",
-				abbrev, one_sha1, abbrev,
-				sha1_to_hex(two->sha1));
-		if (one->mode == two->mode)
-			len += snprintf(msg + len, sizeof(msg) - len,
-					" %06o", one->mode);
-		len += snprintf(msg + len, sizeof(msg) - len, "\n");
-	}
-
-	if (len)
-		msg[--len] = 0;
-	xfrm_msg = len ? msg : NULL;
+	unsigned int mode, oldmode;
+	unsigned char *sha1;
 
-	if (!pgm &&
-	    DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
-	    (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
-		/* a filepair that changes between file and symlink
-		 * needs to be split into deletion and creation.
-		 */
-		struct diff_filespec *null = alloc_filespec(two->path);
-		run_diff_cmd(NULL, name, other, one, null, xfrm_msg, 0);
-		free(null);
-		null = alloc_filespec(one->path);
-		run_diff_cmd(NULL, name, other, null, two, xfrm_msg, 0);
-		free(null);
-	}
-	else
-		run_diff_cmd(pgm, name, other, one, two, xfrm_msg,
-			     complete_rewrite);
-
-	free(name_munged);
-	free(other_munged);
-}
-
-static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
-			 struct diffstat_t *diffstat)
-{
-	const char *name;
-	const char *other;
-
-	if (DIFF_PAIR_UNMERGED(p)) {
-		/* unmerged */
-		builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat);
-		return;
-	}
-
-	name = p->one->path;
-	other = (strcmp(name, p->two->path) ? p->two->path : NULL);
-
-	diff_fill_sha1_info(p->one);
-	diff_fill_sha1_info(p->two);
-
-	builtin_diffstat(name, other, p->one, p->two, diffstat);
-}
-
-void diff_setup(struct diff_options *options)
-{
-	memset(options, 0, sizeof(*options));
-	options->output_format = DIFF_FORMAT_RAW;
-	options->line_termination = '\n';
-	options->break_opt = -1;
-	options->rename_limit = -1;
-
-	options->change = diff_change;
-	options->add_remove = diff_addremove;
-}
-
-int diff_setup_done(struct diff_options *options)
-{
-	if ((options->find_copies_harder &&
-	     options->detect_rename != DIFF_DETECT_COPY) ||
-	    (0 <= options->rename_limit && !options->detect_rename))
+	if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
+		if (report_missing)
+			diff_index_show_file(revs, "-", old,
+					     old->sha1, old->ce_mode);
 		return -1;
-
-	/*
-	 * These cases always need recursive; we do not drop caller-supplied
-	 * recursive bits for other formats here.
-	 */
-	if ((options->output_format == DIFF_FORMAT_PATCH) ||
-	    (options->output_format == DIFF_FORMAT_DIFFSTAT))
-		options->recursive = 1;
-
-	if (options->detect_rename && options->rename_limit < 0)
-		options->rename_limit = diff_rename_limit_default;
-	if (options->setup & DIFF_SETUP_USE_CACHE) {
-		if (!active_cache)
-			/* read-cache does not die even when it fails
-			 * so it is safe for us to do this here.  Also
-			 * it does not smudge active_cache or active_nr
-			 * when it fails, so we do not have to worry about
-			 * cleaning it up ourselves either.
-			 */
-			read_cache();
 	}
-	if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
-		use_size_cache = 1;
-	if (options->abbrev <= 0 || 40 < options->abbrev)
-		options->abbrev = 40; /* full */
-
-	return 0;
-}
 
-int diff_opt_parse(struct diff_options *options, const char **av, int ac)
-{
-	const char *arg = av[0];
-	if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
-		options->output_format = DIFF_FORMAT_PATCH;
-	else if (!strcmp(arg, "--patch-with-raw")) {
-		options->output_format = DIFF_FORMAT_PATCH;
-		options->with_raw = 1;
-	}
-	else if (!strcmp(arg, "--stat"))
-		options->output_format = DIFF_FORMAT_DIFFSTAT;
-	else if (!strcmp(arg, "--patch-with-stat")) {
-		options->output_format = DIFF_FORMAT_PATCH;
-		options->with_stat = 1;
-	}
-	else if (!strcmp(arg, "-z"))
-		options->line_termination = 0;
-	else if (!strncmp(arg, "-l", 2))
-		options->rename_limit = strtoul(arg+2, NULL, 10);
-	else if (!strcmp(arg, "--full-index"))
-		options->full_index = 1;
-	else if (!strcmp(arg, "--name-only"))
-		options->output_format = DIFF_FORMAT_NAME;
-	else if (!strcmp(arg, "--name-status"))
-		options->output_format = DIFF_FORMAT_NAME_STATUS;
-	else if (!strcmp(arg, "-R"))
-		options->reverse_diff = 1;
-	else if (!strncmp(arg, "-S", 2))
-		options->pickaxe = arg + 2;
-	else if (!strcmp(arg, "-s"))
-		options->output_format = DIFF_FORMAT_NO_OUTPUT;
-	else if (!strncmp(arg, "-O", 2))
-		options->orderfile = arg + 2;
-	else if (!strncmp(arg, "--diff-filter=", 14))
-		options->filter = arg + 14;
-	else if (!strcmp(arg, "--pickaxe-all"))
-		options->pickaxe_opts = DIFF_PICKAXE_ALL;
-	else if (!strcmp(arg, "--pickaxe-regex"))
-		options->pickaxe_opts = DIFF_PICKAXE_REGEX;
-	else if (!strncmp(arg, "-B", 2)) {
-		if ((options->break_opt =
-		     diff_scoreopt_parse(arg)) == -1)
-			return -1;
-	}
-	else if (!strncmp(arg, "-M", 2)) {
-		if ((options->rename_score =
-		     diff_scoreopt_parse(arg)) == -1)
-			return -1;
-		options->detect_rename = DIFF_DETECT_RENAME;
-	}
-	else if (!strncmp(arg, "-C", 2)) {
-		if ((options->rename_score =
-		     diff_scoreopt_parse(arg)) == -1)
-			return -1;
-		options->detect_rename = DIFF_DETECT_COPY;
-	}
-	else if (!strcmp(arg, "--find-copies-harder"))
-		options->find_copies_harder = 1;
-	else if (!strcmp(arg, "--abbrev"))
-		options->abbrev = DEFAULT_ABBREV;
-	else if (!strncmp(arg, "--abbrev=", 9)) {
-		options->abbrev = strtoul(arg + 9, NULL, 10);
-		if (options->abbrev < MINIMUM_ABBREV)
-			options->abbrev = MINIMUM_ABBREV;
-		else if (40 < options->abbrev)
-			options->abbrev = 40;
-	}
-	else
+	oldmode = old->ce_mode;
+	if (mode == oldmode && !memcmp(sha1, old->sha1, 20) &&
+	    !revs->diffopt.find_copies_harder)
 		return 0;
-	return 1;
-}
-
-static int parse_num(const char **cp_p)
-{
-	unsigned long num, scale;
-	int ch, dot;
-	const char *cp = *cp_p;
-
-	num = 0;
-	scale = 1;
-	dot = 0;
-	for(;;) {
-		ch = *cp;
-		if ( !dot && ch == '.' ) {
-			scale = 1;
-			dot = 1;
-		} else if ( ch == '%' ) {
-			scale = dot ? scale*100 : 100;
-			cp++;	/* % is always at the end */
-			break;
-		} else if ( ch >= '0' && ch <= '9' ) {
-			if ( scale < 100000 ) {
-				scale *= 10;
-				num = (num*10) + (ch-'0');
-			}
-		} else {
-			break;
-		}
-		cp++;
-	}
-	*cp_p = cp;
-
-	/* user says num divided by scale and we say internally that
-	 * is MAX_SCORE * num / scale.
-	 */
-	return (num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale);
-}
-
-int diff_scoreopt_parse(const char *opt)
-{
-	int opt1, opt2, cmd;
-
-	if (*opt++ != '-')
-		return -1;
-	cmd = *opt++;
-	if (cmd != 'M' && cmd != 'C' && cmd != 'B')
-		return -1; /* that is not a -M, -C nor -B option */
-
-	opt1 = parse_num(&opt);
-	if (cmd != 'B')
-		opt2 = 0;
-	else {
-		if (*opt == 0)
-			opt2 = 0;
-		else if (*opt != '/')
-			return -1; /* we expect -B80/99 or -B80 */
-		else {
-			opt++;
-			opt2 = parse_num(&opt);
-		}
-	}
-	if (*opt != 0)
-		return -1;
-	return opt1 | (opt2 << 16);
-}
-
-struct diff_queue_struct diff_queued_diff;
-
-void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
-{
-	if (queue->alloc <= queue->nr) {
-		queue->alloc = alloc_nr(queue->alloc);
-		queue->queue = xrealloc(queue->queue,
-					sizeof(dp) * queue->alloc);
-	}
-	queue->queue[queue->nr++] = dp;
-}
-
-struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
-				 struct diff_filespec *one,
-				 struct diff_filespec *two)
-{
-	struct diff_filepair *dp = xmalloc(sizeof(*dp));
-	dp->one = one;
-	dp->two = two;
-	dp->score = 0;
-	dp->status = 0;
-	dp->source_stays = 0;
-	dp->broken_pair = 0;
-	if (queue)
-		diff_q(queue, dp);
-	return dp;
-}
-
-void diff_free_filepair(struct diff_filepair *p)
-{
-	diff_free_filespec_data(p->one);
-	diff_free_filespec_data(p->two);
-	free(p->one);
-	free(p->two);
-	free(p);
-}
-
-/* This is different from find_unique_abbrev() in that
- * it stuffs the result with dots for alignment.
- */
-const char *diff_unique_abbrev(const unsigned char *sha1, int len)
-{
-	int abblen;
-	const char *abbrev;
-	if (len == 40)
-		return sha1_to_hex(sha1);
-
-	abbrev = find_unique_abbrev(sha1, len);
-	if (!abbrev)
-		return sha1_to_hex(sha1);
-	abblen = strlen(abbrev);
-	if (abblen < 37) {
-		static char hex[41];
-		if (len < abblen && abblen <= len + 2)
-			sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
-		else
-			sprintf(hex, "%s...", abbrev);
-		return hex;
-	}
-	return sha1_to_hex(sha1);
-}
-
-static void diff_flush_raw(struct diff_filepair *p,
-			   int line_termination,
-			   int inter_name_termination,
-			   struct diff_options *options,
-			   int output_format)
-{
-	int two_paths;
-	char status[10];
-	int abbrev = options->abbrev;
-	const char *path_one, *path_two;
-
-	path_one = p->one->path;
-	path_two = p->two->path;
-	if (line_termination) {
-		path_one = quote_one(path_one);
-		path_two = quote_one(path_two);
-	}
-
-	if (p->score)
-		sprintf(status, "%c%03d", p->status,
-			(int)(0.5 + p->score * 100.0/MAX_SCORE));
-	else {
-		status[0] = p->status;
-		status[1] = 0;
-	}
-	switch (p->status) {
-	case DIFF_STATUS_COPIED:
-	case DIFF_STATUS_RENAMED:
-		two_paths = 1;
-		break;
-	case DIFF_STATUS_ADDED:
-	case DIFF_STATUS_DELETED:
-		two_paths = 0;
-		break;
-	default:
-		two_paths = 0;
-		break;
-	}
-	if (output_format != DIFF_FORMAT_NAME_STATUS) {
-		printf(":%06o %06o %s ",
-		       p->one->mode, p->two->mode,
-		       diff_unique_abbrev(p->one->sha1, abbrev));
-		printf("%s ",
-		       diff_unique_abbrev(p->two->sha1, abbrev));
-	}
-	printf("%s%c%s", status, inter_name_termination, path_one);
-	if (two_paths)
-		printf("%c%s", inter_name_termination, path_two);
-	putchar(line_termination);
-	if (path_one != p->one->path)
-		free((void*)path_one);
-	if (path_two != p->two->path)
-		free((void*)path_two);
-}
-
-static void diff_flush_name(struct diff_filepair *p,
-			    int inter_name_termination,
-			    int line_termination)
-{
-	char *path = p->two->path;
-
-	if (line_termination)
-		path = quote_one(p->two->path);
-	else
-		path = p->two->path;
-	printf("%s%c", path, line_termination);
-	if (p->two->path != path)
-		free(path);
-}
-
-int diff_unmodified_pair(struct diff_filepair *p)
-{
-	/* This function is written stricter than necessary to support
-	 * the currently implemented transformers, but the idea is to
-	 * let transformers to produce diff_filepairs any way they want,
-	 * and filter and clean them up here before producing the output.
-	 */
-	struct diff_filespec *one, *two;
 
-	if (DIFF_PAIR_UNMERGED(p))
-		return 0; /* unmerged is interesting */
+	mode = ntohl(mode);
+	oldmode = ntohl(oldmode);
 
-	one = p->one;
-	two = p->two;
-
-	/* deletion, addition, mode or type change
-	 * and rename are all interesting.
-	 */
-	if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
-	    DIFF_PAIR_MODE_CHANGED(p) ||
-	    strcmp(one->path, two->path))
-		return 0;
-
-	/* both are valid and point at the same path.  that is, we are
-	 * dealing with a change.
-	 */
-	if (one->sha1_valid && two->sha1_valid &&
-	    !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
-		return 1; /* no change */
-	if (!one->sha1_valid && !two->sha1_valid)
-		return 1; /* both look at the same file on the filesystem. */
+	diff_change(&revs->diffopt, oldmode, mode,
+		    old->sha1, sha1, old->name, NULL);
 	return 0;
 }
 
-static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
+static int diff_cache(struct rev_info *revs,
+		      struct cache_entry **ac, int entries,
+		      const char **pathspec,
+		      int cached, int match_missing)
 {
-	if (diff_unmodified_pair(p))
-		return;
+	while (entries) {
+		struct cache_entry *ce = *ac;
+		int same = (entries > 1) && ce_same_name(ce, ac[1]);
 
-	if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
-	    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
-		return; /* no tree diffs in patch format */
+		if (!ce_path_match(ce, pathspec))
+			goto skip_entry;
 
-	run_diff(p, o);
-}
-
-static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
-			    struct diffstat_t *diffstat)
-{
-	if (diff_unmodified_pair(p))
-		return;
-
-	if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
-	    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
-		return; /* no tree diffs in patch format */
-
-	run_diffstat(p, o, diffstat);
-}
-
-int diff_queue_is_empty(void)
-{
-	struct diff_queue_struct *q = &diff_queued_diff;
-	int i;
-	for (i = 0; i < q->nr; i++)
-		if (!diff_unmodified_pair(q->queue[i]))
-			return 0;
-	return 1;
-}
-
-#if DIFF_DEBUG
-void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
-{
-	fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
-		x, one ? one : "",
-		s->path,
-		DIFF_FILE_VALID(s) ? "valid" : "invalid",
-		s->mode,
-		s->sha1_valid ? sha1_to_hex(s->sha1) : "");
-	fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
-		x, one ? one : "",
-		s->size, s->xfrm_flags);
-}
-
-void diff_debug_filepair(const struct diff_filepair *p, int i)
-{
-	diff_debug_filespec(p->one, i, "one");
-	diff_debug_filespec(p->two, i, "two");
-	fprintf(stderr, "score %d, status %c stays %d broken %d\n",
-		p->score, p->status ? p->status : '?',
-		p->source_stays, p->broken_pair);
-}
-
-void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
-{
-	int i;
-	if (msg)
-		fprintf(stderr, "%s\n", msg);
-	fprintf(stderr, "q->nr = %d\n", q->nr);
-	for (i = 0; i < q->nr; i++) {
-		struct diff_filepair *p = q->queue[i];
-		diff_debug_filepair(p, i);
-	}
-}
-#endif
-
-static void diff_resolve_rename_copy(void)
-{
-	int i, j;
-	struct diff_filepair *p, *pp;
-	struct diff_queue_struct *q = &diff_queued_diff;
-
-	diff_debug_queue("resolve-rename-copy", q);
-
-	for (i = 0; i < q->nr; i++) {
-		p = q->queue[i];
-		p->status = 0; /* undecided */
-		if (DIFF_PAIR_UNMERGED(p))
-			p->status = DIFF_STATUS_UNMERGED;
-		else if (!DIFF_FILE_VALID(p->one))
-			p->status = DIFF_STATUS_ADDED;
-		else if (!DIFF_FILE_VALID(p->two))
-			p->status = DIFF_STATUS_DELETED;
-		else if (DIFF_PAIR_TYPE_CHANGED(p))
-			p->status = DIFF_STATUS_TYPE_CHANGED;
-
-		/* from this point on, we are dealing with a pair
-		 * whose both sides are valid and of the same type, i.e.
-		 * either in-place edit or rename/copy edit.
-		 */
-		else if (DIFF_PAIR_RENAME(p)) {
-			if (p->source_stays) {
-				p->status = DIFF_STATUS_COPIED;
-				continue;
+		switch (ce_stage(ce)) {
+		case 0:
+			/* No stage 1 entry? That means it's a new file */
+			if (!same) {
+				show_new_file(revs, ce, cached, match_missing);
+				break;
 			}
-			/* See if there is some other filepair that
-			 * copies from the same source as us.  If so
-			 * we are a copy.  Otherwise we are either a
-			 * copy if the path stays, or a rename if it
-			 * does not, but we already handled "stays" case.
+			/* Show difference between old and new */
+			show_modified(revs,ac[1], ce, 1,
+				      cached, match_missing);
+			break;
+		case 1:
+			/* No stage 3 (merge) entry?
+			 * That means it's been deleted.
 			 */
-			for (j = i + 1; j < q->nr; j++) {
-				pp = q->queue[j];
-				if (strcmp(pp->one->path, p->one->path))
-					continue; /* not us */
-				if (!DIFF_PAIR_RENAME(pp))
-					continue; /* not a rename/copy */
-				/* pp is a rename/copy from the same source */
-				p->status = DIFF_STATUS_COPIED;
+			if (!same) {
+				diff_index_show_file(revs, "-", ce,
+						     ce->sha1, ce->ce_mode);
 				break;
 			}
-			if (!p->status)
-				p->status = DIFF_STATUS_RENAMED;
-		}
-		else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
-			 p->one->mode != p->two->mode)
-			p->status = DIFF_STATUS_MODIFIED;
-		else {
-			/* This is a "no-change" entry and should not
-			 * happen anymore, but prepare for broken callers.
+			/* We come here with ce pointing at stage 1
+			 * (original tree) and ac[1] pointing at stage
+			 * 3 (unmerged).  show-modified with
+			 * report-missing set to false does not say the
+			 * file is deleted but reports true if work
+			 * tree does not have it, in which case we
+			 * fall through to report the unmerged state.
+			 * Otherwise, we show the differences between
+			 * the original tree and the work tree.
 			 */
-			error("feeding unmodified %s to diffcore",
-			      p->one->path);
-			p->status = DIFF_STATUS_UNKNOWN;
-		}
-	}
-	diff_debug_queue("resolve-rename-copy done", q);
-}
-
-static void flush_one_pair(struct diff_filepair *p,
-			   int diff_output_format,
-			   struct diff_options *options,
-			   struct diffstat_t *diffstat)
-{
-	int inter_name_termination = '\t';
-	int line_termination = options->line_termination;
-	if (!line_termination)
-		inter_name_termination = 0;
-
-	switch (p->status) {
-	case DIFF_STATUS_UNKNOWN:
-		break;
-	case 0:
-		die("internal error in diff-resolve-rename-copy");
-		break;
-	default:
-		switch (diff_output_format) {
-		case DIFF_FORMAT_DIFFSTAT:
-			diff_flush_stat(p, options, diffstat);
-			break;
-		case DIFF_FORMAT_PATCH:
-			diff_flush_patch(p, options);
-			break;
-		case DIFF_FORMAT_RAW:
-		case DIFF_FORMAT_NAME_STATUS:
-			diff_flush_raw(p, line_termination,
-				       inter_name_termination,
-				       options, diff_output_format);
-			break;
-		case DIFF_FORMAT_NAME:
-			diff_flush_name(p,
-					inter_name_termination,
-					line_termination);
-			break;
-		case DIFF_FORMAT_NO_OUTPUT:
+			if (!cached &&
+			    !show_modified(revs, ce, ac[1], 0,
+					   cached, match_missing))
+				break;
+			/* fallthru */
+		case 3:
+			diff_unmerge(&revs->diffopt, ce->name);
 			break;
-		}
-	}
-}
 
-void diff_flush(struct diff_options *options)
-{
-	struct diff_queue_struct *q = &diff_queued_diff;
-	int i;
-	int diff_output_format = options->output_format;
-	struct diffstat_t *diffstat = NULL;
-
-	if (diff_output_format == DIFF_FORMAT_DIFFSTAT || options->with_stat) {
-		diffstat = xcalloc(sizeof (struct diffstat_t), 1);
-		diffstat->xm.consume = diffstat_consume;
-	}
-
-	if (options->with_raw) {
-		for (i = 0; i < q->nr; i++) {
-			struct diff_filepair *p = q->queue[i];
-			flush_one_pair(p, DIFF_FORMAT_RAW, options, NULL);
-		}
-		putchar(options->line_termination);
-	}
-	if (options->with_stat) {
-		for (i = 0; i < q->nr; i++) {
-			struct diff_filepair *p = q->queue[i];
-			flush_one_pair(p, DIFF_FORMAT_DIFFSTAT, options,
-				       diffstat);
+		default:
+			die("impossible cache entry stage");
 		}
-		show_stats(diffstat);
-		free(diffstat);
-		diffstat = NULL;
-		putchar(options->line_termination);
-	}
-	for (i = 0; i < q->nr; i++) {
-		struct diff_filepair *p = q->queue[i];
-		flush_one_pair(p, diff_output_format, options, diffstat);
-		diff_free_filepair(p);
-	}
 
-	if (diffstat) {
-		show_stats(diffstat);
-		free(diffstat);
+skip_entry:
+		/*
+		 * Ignore all the different stages for this file,
+		 * we've handled the relevant cases now.
+		 */
+		do {
+			ac++;
+			entries--;
+		} while (entries && ce_same_name(ce, ac[0]));
 	}
-
-	free(q->queue);
-	q->queue = NULL;
-	q->nr = q->alloc = 0;
+	return 0;
 }
 
-static void diffcore_apply_filter(const char *filter)
+/*
+ * This turns all merge entries into "stage 3". That guarantees that
+ * when we read in the new tree (into "stage 1"), we won't lose sight
+ * of the fact that we had unmerged entries.
+ */
+static void mark_merge_entries(void)
 {
 	int i;
-	struct diff_queue_struct *q = &diff_queued_diff;
-	struct diff_queue_struct outq;
-	outq.queue = NULL;
-	outq.nr = outq.alloc = 0;
-
-	if (!filter)
-		return;
-
-	if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
-		int found;
-		for (i = found = 0; !found && i < q->nr; i++) {
-			struct diff_filepair *p = q->queue[i];
-			if (((p->status == DIFF_STATUS_MODIFIED) &&
-			     ((p->score &&
-			       strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
-			      (!p->score &&
-			       strchr(filter, DIFF_STATUS_MODIFIED)))) ||
-			    ((p->status != DIFF_STATUS_MODIFIED) &&
-			     strchr(filter, p->status)))
-				found++;
-		}
-		if (found)
-			return;
-
-		/* otherwise we will clear the whole queue
-		 * by copying the empty outq at the end of this
-		 * function, but first clear the current entries
-		 * in the queue.
-		 */
-		for (i = 0; i < q->nr; i++)
-			diff_free_filepair(q->queue[i]);
-	}
-	else {
-		/* Only the matching ones */
-		for (i = 0; i < q->nr; i++) {
-			struct diff_filepair *p = q->queue[i];
-
-			if (((p->status == DIFF_STATUS_MODIFIED) &&
-			     ((p->score &&
-			       strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
-			      (!p->score &&
-			       strchr(filter, DIFF_STATUS_MODIFIED)))) ||
-			    ((p->status != DIFF_STATUS_MODIFIED) &&
-			     strchr(filter, p->status)))
-				diff_q(&outq, p);
-			else
-				diff_free_filepair(p);
-		}
+	for (i = 0; i < active_nr; i++) {
+		struct cache_entry *ce = active_cache[i];
+		if (!ce_stage(ce))
+			continue;
+		ce->ce_flags |= htons(CE_STAGEMASK);
 	}
-	free(q->queue);
-	*q = outq;
-}
-
-void diffcore_std(struct diff_options *options)
-{
-	if (options->break_opt != -1)
-		diffcore_break(options->break_opt);
-	if (options->detect_rename)
-		diffcore_rename(options);
-	if (options->break_opt != -1)
-		diffcore_merge_broken();
-	if (options->pickaxe)
-		diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
-	if (options->orderfile)
-		diffcore_order(options->orderfile);
-	diff_resolve_rename_copy();
-	diffcore_apply_filter(options->filter);
-}
-
-
-void diffcore_std_no_resolve(struct diff_options *options)
-{
-	if (options->pickaxe)
-		diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
-	if (options->orderfile)
-		diffcore_order(options->orderfile);
-	diffcore_apply_filter(options->filter);
 }
 
-void diff_addremove(struct diff_options *options,
-		    int addremove, unsigned mode,
-		    const unsigned char *sha1,
-		    const char *base, const char *path)
+int run_diff_index(struct rev_info *revs, int cached)
 {
-	char concatpath[PATH_MAX];
-	struct diff_filespec *one, *two;
+	int ret;
+	struct object *ent;
+	struct tree *tree;
+	const char *tree_name;
+	int match_missing = 0;
 
-	/* This may look odd, but it is a preparation for
-	 * feeding "there are unchanged files which should
-	 * not produce diffs, but when you are doing copy
-	 * detection you would need them, so here they are"
-	 * entries to the diff-core.  They will be prefixed
-	 * with something like '=' or '*' (I haven't decided
-	 * which but should not make any difference).
-	 * Feeding the same new and old to diff_change() 
-	 * also has the same effect.
-	 * Before the final output happens, they are pruned after
-	 * merged into rename/copy pairs as appropriate.
+	/* 
+	 * Backward compatibility wart - "diff-index -m" does
+	 * not mean "do not ignore merges", but totally different.
 	 */
-	if (options->reverse_diff)
-		addremove = (addremove == '+' ? '-' :
-			     addremove == '-' ? '+' : addremove);
-
-	if (!path) path = "";
-	sprintf(concatpath, "%s%s", base, path);
-	one = alloc_filespec(concatpath);
-	two = alloc_filespec(concatpath);
-
-	if (addremove != '+')
-		fill_filespec(one, sha1, mode);
-	if (addremove != '-')
-		fill_filespec(two, sha1, mode);
+	if (!revs->ignore_merges)
+		match_missing = 1;
 
-	diff_queue(&diff_queued_diff, one, two);
-}
-
-void diff_change(struct diff_options *options,
-		 unsigned old_mode, unsigned new_mode,
-		 const unsigned char *old_sha1,
-		 const unsigned char *new_sha1,
-		 const char *base, const char *path) 
-{
-	char concatpath[PATH_MAX];
-	struct diff_filespec *one, *two;
-
-	if (options->reverse_diff) {
-		unsigned tmp;
-		const unsigned char *tmp_c;
-		tmp = old_mode; old_mode = new_mode; new_mode = tmp;
-		tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
+	if (read_cache() < 0) {
+		perror("read_cache");
+		return -1;
 	}
-	if (!path) path = "";
-	sprintf(concatpath, "%s%s", base, path);
-	one = alloc_filespec(concatpath);
-	two = alloc_filespec(concatpath);
-	fill_filespec(one, old_sha1, old_mode);
-	fill_filespec(two, new_sha1, new_mode);
-
-	diff_queue(&diff_queued_diff, one, two);
-}
-
-void diff_unmerge(struct diff_options *options,
-		  const char *path)
-{
-	struct diff_filespec *one, *two;
-	one = alloc_filespec(path);
-	two = alloc_filespec(path);
-	diff_queue(&diff_queued_diff, one, two);
+	mark_merge_entries();
+
+	ent = revs->pending_objects->item;
+	tree_name = revs->pending_objects->name;
+	tree = parse_tree_indirect(ent->sha1);
+	if (!tree)
+		return error("bad tree object %s", tree_name);
+	if (read_tree(tree, 1, revs->prune_data))
+		return error("unable to read tree object %s", tree_name);
+	ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
+			 cached, match_missing);
+	diffcore_std(&revs->diffopt);
+	diff_flush(&revs->diffopt);
+	return ret;
 }