patch 9.0.1418: the included xdiff code is a bit outdated

Problem:    The included xdiff code is a bit outdated.
Solution:   Sync with the latest git xdiff code. (Yee Cheng Chin,
            closes #12181)

Author: ychin

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1418,
 /**/
     1417,
 /**/

src/xdiff/README.txt

@@ -1,6 +1,6 @@
 The files in this directory come from the xdiff implementation in git.
 You can find it here: https://github.com/git/git/tree/master/xdiff
-The files were last updated August 31, 2021 from git release v.2.33.0
+The files were last updated March 17, 2023 from git release v.2.40.0
 
 This is originally based on libxdiff, which can be found here:
 http://www.xmailserver.org/xdiff-lib.html

src/xdiff/xdiff.h

@@ -66,6 +66,7 @@ extern "C" {
 
 /* merge output styles */
 #define XDL_MERGE_DIFF3 1
+#define XDL_MERGE_ZEALOUS_DIFF3 2
 
 typedef struct s_mmfile {
 	char *ptr;
@@ -126,6 +127,7 @@ typedef struct s_bdiffparam {
 #endif
 
 #define xdl_malloc(x) lalloc((x), TRUE)
+#define xdl_calloc(n, sz) lalloc_clear(n*sz, TRUE)
 #define xdl_free(ptr) vim_free(ptr)
 #define xdl_realloc(ptr,x) vim_realloc((ptr),(x))
 

src/xdiff/xdiffi.c

@@ -315,16 +315,19 @@ int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 	long *kvd, *kvdf, *kvdb;
 	xdalgoenv_t xenv;
 	diffdata_t dd1, dd2;
+	int res;
 
-	if (XDF_DIFF_ALG(xpp->flags) == XDF_PATIENCE_DIFF)
-		return xdl_do_patience_diff(mf1, mf2, xpp, xe);
-
-	if (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF)
-		return xdl_do_histogram_diff(mf1, mf2, xpp, xe);
+	if (xdl_prepare_env(mf1, mf2, xpp, xe) < 0)
+		return -1;
 
-	if (xdl_prepare_env(mf1, mf2, xpp, xe) < 0) {
+	if (XDF_DIFF_ALG(xpp->flags) == XDF_PATIENCE_DIFF) {
+		res = xdl_do_patience_diff(xpp, xe);
+		goto out;
+	}
 
-		return -1;
+	if (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF) {
+		res = xdl_do_histogram_diff(xpp, xe);
+		goto out;
 	}
 
 	/*
@@ -334,7 +337,7 @@ int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 	 * One is to store the forward path and one to store the backward path.
 	 */
 	ndiags = xe->xdf1.nreff + xe->xdf2.nreff + 3;
-	if (!(kvd = (long *) xdl_malloc((2 * ndiags + 2) * sizeof(long)))) {
+	if (!XDL_ALLOC_ARRAY(kvd, 2 * ndiags + 2)) {
 
 		xdl_free_env(xe);
 		return -1;
@@ -359,17 +362,15 @@ int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 	dd2.rchg = xe->xdf2.rchg;
 	dd2.rindex = xe->xdf2.rindex;
 
-	if (xdl_recs_cmp(&dd1, 0, dd1.nrec, &dd2, 0, dd2.nrec,
-			 kvdf, kvdb, (xpp->flags & XDF_NEED_MINIMAL) != 0, &xenv) < 0) {
-
-		xdl_free(kvd);
-		xdl_free_env(xe);
-		return -1;
-	}
-
+	res = xdl_recs_cmp(&dd1, 0, dd1.nrec, &dd2, 0, dd2.nrec,
+			   kvdf, kvdb, (xpp->flags & XDF_NEED_MINIMAL) != 0,
+			   &xenv);
 	xdl_free(kvd);
+ out:
+	if (res < 0)
+		xdl_free_env(xe);
 
-	return 0;
+	return res;
 }
 
 
@@ -390,12 +391,9 @@ static xdchange_t *xdl_add_change(xdchange_t *xscr, long i1, long i2, long chg1,
 }
 
 
-static int recs_match(xrecord_t *rec1, xrecord_t *rec2, long flags)
+static int recs_match(xrecord_t *rec1, xrecord_t *rec2)
 {
-	return (rec1->ha == rec2->ha &&
-		xdl_recmatch(rec1->ptr, rec1->size,
-			     rec2->ptr, rec2->size,
-			     flags));
+	return (rec1->ha == rec2->ha);
 }
 
 /*
@@ -759,10 +757,10 @@ static inline int group_previous(xdfile_t *xdf, struct xdlgroup *g)
  * following group, expand this group to include it. Return 0 on success or -1
  * if g cannot be slid down.
  */
-static int group_slide_down(xdfile_t *xdf, struct xdlgroup *g, long flags)
+static int group_slide_down(xdfile_t *xdf, struct xdlgroup *g)
 {
 	if (g->end < xdf->nrec &&
-	    recs_match(xdf->recs[g->start], xdf->recs[g->end], flags)) {
+	    recs_match(xdf->recs[g->start], xdf->recs[g->end])) {
 		xdf->rchg[g->start++] = 0;
 		xdf->rchg[g->end++] = 1;
 
@@ -780,10 +778,10 @@ static int group_slide_down(xdfile_t *xdf, struct xdlgroup *g, long flags)
  * into a previous group, expand this group to include it. Return 0 on success
  * or -1 if g cannot be slid up.
  */
-static int group_slide_up(xdfile_t *xdf, struct xdlgroup *g, long flags)
+static int group_slide_up(xdfile_t *xdf, struct xdlgroup *g)
 {
 	if (g->start > 0 &&
-	    recs_match(xdf->recs[g->start - 1], xdf->recs[g->end - 1], flags)) {
+	    recs_match(xdf->recs[g->start - 1], xdf->recs[g->end - 1])) {
 		xdf->rchg[--g->start] = 1;
 		xdf->rchg[--g->end] = 0;
 
@@ -839,7 +837,7 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
 			end_matching_other = -1;
 
 			/* Shift the group backward as much as possible: */
-			while (!group_slide_up(xdf, &g, flags))
+			while (!group_slide_up(xdf, &g))
 				if (group_previous(xdfo, &go))
 					xdl_bug("group sync broken sliding up");
 
@@ -854,7 +852,7 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
 
 			/* Now shift the group forward as far as possible: */
 			while (1) {
-				if (group_slide_down(xdf, &g, flags))
+				if (group_slide_down(xdf, &g))
 					break;
 				if (group_next(xdfo, &go))
 					xdl_bug("group sync broken sliding down");
@@ -881,7 +879,7 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
 			 * other file that it can align with.
 			 */
 			while (go.end == go.start) {
-				if (group_slide_up(xdf, &g, flags))
+				if (group_slide_up(xdf, &g))
 					xdl_bug("match disappeared");
 				if (group_previous(xdfo, &go))
 					xdl_bug("group sync broken sliding to match");
@@ -924,7 +922,7 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
 			}
 
 			while (g.end > best_shift) {
-				if (group_slide_up(xdf, &g, flags))
+				if (group_slide_up(xdf, &g))
 					xdl_bug("best shift unreached");
 				if (group_previous(xdfo, &go))
 					xdl_bug("group sync broken sliding to blank line");

src/xdiff/xdiffi.h

@@ -56,9 +56,7 @@ int xdl_build_script(xdfenv_t *xe, xdchange_t **xscr);
 void xdl_free_script(xdchange_t *xscr);
 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 		  xdemitconf_t const *xecfg);
-int xdl_do_patience_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
-		xdfenv_t *env);
-int xdl_do_histogram_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
-		xdfenv_t *env);
+int xdl_do_patience_diff(xpparam_t const *xpp, xdfenv_t *env);
+int xdl_do_histogram_diff(xpparam_t const *xpp, xdfenv_t *env);
 
 #endif /* #if !defined(XDIFFI_H) */

src/xdiff/xemit.c

@@ -65,7 +65,7 @@ xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
 			*xscr = xch;
 	}
 
-	if (*xscr == NULL)
+	if (!*xscr)
 		return NULL;
 
 	lxch = *xscr;
@@ -96,7 +96,7 @@ xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
 
 
 #if 0
-static long def_ff(const char *rec, long len, char *buf, long sz, void *priv UNUSED)
+static long def_ff(const char *rec, long len, char *buf, long sz)
 {
 	if (len > 0 &&
 			(isalpha((unsigned char)*rec) || /* identifier? */
@@ -120,7 +120,7 @@ static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
 	const char *rec;
 	long len = xdl_get_rec(xdf, ri, &rec);
 	if (!xecfg->find_func)
-		return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
+		return def_ff(rec, len, buf, sz);
 	return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
 }
 #endif

src/xdiff/xhistogram.c

@@ -88,19 +88,14 @@ struct region {
 #define REC(env, s, l) \
 	(env->xdf##s.recs[l - 1])
 
-static int cmp_recs(xpparam_t const *xpp,
-	xrecord_t *r1, xrecord_t *r2)
+static int cmp_recs(xrecord_t *r1, xrecord_t *r2)
 {
-	return r1->ha == r2->ha &&
-		xdl_recmatch(r1->ptr, r1->size, r2->ptr, r2->size,
-			    xpp->flags);
-}
+	return r1->ha == r2->ha;
 
-#define CMP_ENV(xpp, env, s1, l1, s2, l2) \
-	(cmp_recs(xpp, REC(env, s1, l1), REC(env, s2, l2)))
+}
 
 #define CMP(i, s1, l1, s2, l2) \
-	(cmp_recs(i->xpp, REC(i->env, s1, l1), REC(i->env, s2, l2)))
+	(cmp_recs(REC(i->env, s1, l1), REC(i->env, s2, l2)))
 
 #define TABLE_HASH(index, side, line) \
 	XDL_HASHLONG((REC(index->env, side, line))->ha, index->table_bits)
@@ -256,7 +251,7 @@ static int find_lcs(xpparam_t const *xpp, xdfenv_t *env,
 		    int line1, int count1, int line2, int count2)
 {
 	int b_ptr;
-	int sz, ret = -1;
+	int ret = -1;
 	struct histindex index;
 
 	memset(&index, 0, sizeof(index));
@@ -270,23 +265,16 @@ static int find_lcs(xpparam_t const *xpp, xdfenv_t *env,
 	index.rcha.head = NULL;
 
 	index.table_bits = xdl_hashbits(count1);
-	sz = index.records_size = 1 << index.table_bits;
-	sz *= sizeof(struct record *);
-	if (!(index.records = (struct record **) xdl_malloc(sz)))
+	index.records_size = 1 << index.table_bits;
+	if (!XDL_CALLOC_ARRAY(index.records, index.records_size))
 		goto cleanup;
-	memset(index.records, 0, sz);
 
-	sz = index.line_map_size = count1;
-	sz *= sizeof(struct record *);
-	if (!(index.line_map = (struct record **) xdl_malloc(sz)))
+	index.line_map_size = count1;
+	if (!XDL_CALLOC_ARRAY(index.line_map, index.line_map_size))
 		goto cleanup;
-	memset(index.line_map, 0, sz);
 
-	sz = index.line_map_size;
-	sz *= sizeof(unsigned int);
-	if (!(index.next_ptrs = (unsigned int *) xdl_malloc(sz)))
+	if (!XDL_CALLOC_ARRAY(index.next_ptrs, index.line_map_size))
 		goto cleanup;
-	memset(index.next_ptrs, 0, sz);
 
 	/* lines / 4 + 1 comes from xprepare.c:xdl_prepare_ctx() */
 	if (xdl_cha_init(&index.rcha, sizeof(struct record), count1 / 4 + 1) < 0)
@@ -374,12 +362,8 @@ static int histogram_diff(xpparam_t const *xpp, xdfenv_t *env,
 	return result;
 }
 
-int xdl_do_histogram_diff(mmfile_t *file1, mmfile_t *file2,
-	xpparam_t const *xpp, xdfenv_t *env)
+int xdl_do_histogram_diff(xpparam_t const *xpp, xdfenv_t *env)
 {
-	if (xdl_prepare_env(file1, file2, xpp, env) < 0)
-		return -1;
-
 	return histogram_diff(xpp, env,
 		env->xdf1.dstart + 1, env->xdf1.dend - env->xdf1.dstart + 1,
 		env->xdf2.dstart + 1, env->xdf2.dend - env->xdf2.dstart + 1);

src/xdiff/xmacros.h

@@ -34,7 +34,6 @@
 #define XDL_ADDBITS(v,b)	((v) + ((v) >> (b)))
 #define XDL_MASKBITS(b)		((1UL << (b)) - 1)
 #define XDL_HASHLONG(v,b)	(XDL_ADDBITS((unsigned long)(v), b) & XDL_MASKBITS(b))
-#define XDL_PTRFREE(p) do { if (p) { xdl_free(p); (p) = NULL; } } while (0)
 #define XDL_LE32_PUT(p, v) \
 do { \
 	unsigned char *__p = (unsigned char *) (p); \
@@ -50,5 +49,23 @@ do { \
 		((unsigned long) __p[2]) << 16 | ((unsigned long) __p[3]) << 24; \
 } while (0)
 
+/* Allocate an array of nr elements, returns NULL on failure */
+#define XDL_ALLOC_ARRAY(p, nr)				\
+	((p) = SIZE_MAX / sizeof(*(p)) >= (size_t)(nr)	\
+		? xdl_malloc((nr) * sizeof(*(p)))	\
+		: NULL)
+
+/* Allocate an array of nr zeroed out elements, returns NULL on failure */
+#define XDL_CALLOC_ARRAY(p, nr)	((p) = xdl_calloc(nr, sizeof(*(p))))
+
+/*
+ * Ensure array p can accommodate at least nr elements, growing the
+ * array and updating alloc (which is the number of allocated
+ * elements) as necessary. Frees p and returns -1 on failure, returns
+ * 0 on success
+ */
+#define XDL_ALLOC_GROW(p, nr, alloc)	\
+	(-!((nr) <= (alloc) ||		\
+	    ((p) = xdl_alloc_grow_helper((p), (nr), &(alloc), sizeof(*(p))))))
 
 #endif /* #if !defined(XMACROS_H) */