1 files changed, 226 insertions, 28 deletions

diff --git a/xdiff-interface.c b/xdiff-interface.c
index e407cf11b1..b9b0db8d86 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -1,15 +1,24 @@
 #include "cache.h"
 #include "xdiff-interface.h"
+#include "xdiff/xtypes.h"
+#include "xdiff/xdiffi.h"
+#include "xdiff/xemit.h"
+#include "xdiff/xmacros.h"
+
+struct xdiff_emit_state {
+	xdiff_emit_consume_fn consume;
+	void *consume_callback_data;
+	struct strbuf remainder;
+};
 
 static int parse_num(char **cp_p, int *num_p)
 {
 	char *cp = *cp_p;
 	int num = 0;
-	int read_some;
 
 	while ('0' <= *cp && *cp <= '9')
 		num = num * 10 + *cp++ - '0';
-	if (!(read_some = cp - *cp_p))
+	if (!(cp - *cp_p))
 		return -1;
 	*cp_p = cp;
 	*num_p = num;
@@ -55,13 +64,13 @@ static void consume_one(void *priv_, char *s, unsigned long size)
 		unsigned long this_size;
 		ep = memchr(s, '\n', size);
 		this_size = (ep == NULL) ? size : (ep - s + 1);
-		priv->consume(priv, s, this_size);
+		priv->consume(priv->consume_callback_data, s, this_size);
 		size -= this_size;
 		s += this_size;
 	}
 }
 
-int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
+static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
 {
 	struct xdiff_emit_state *priv = priv_;
 	int i;
@@ -69,40 +78,127 @@ int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
 	for (i = 0; i < nbuf; i++) {
 		if (mb[i].ptr[mb[i].size-1] != '\n') {
 			/* Incomplete line */
-			priv->remainder = xrealloc(priv->remainder,
-						   priv->remainder_size +
-						   mb[i].size);
-			memcpy(priv->remainder + priv->remainder_size,
-			       mb[i].ptr, mb[i].size);
-			priv->remainder_size += mb[i].size;
+			strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
 			continue;
 		}
 
 		/* we have a complete line */
-		if (!priv->remainder) {
+		if (!priv->remainder.len) {
 			consume_one(priv, mb[i].ptr, mb[i].size);
 			continue;
 		}
-		priv->remainder = xrealloc(priv->remainder,
-					   priv->remainder_size +
-					   mb[i].size);
-		memcpy(priv->remainder + priv->remainder_size,
-		       mb[i].ptr, mb[i].size);
-		consume_one(priv, priv->remainder,
-			    priv->remainder_size + mb[i].size);
-		free(priv->remainder);
-		priv->remainder = NULL;
-		priv->remainder_size = 0;
+		strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
+		consume_one(priv, priv->remainder.buf, priv->remainder.len);
+		strbuf_reset(&priv->remainder);
 	}
-	if (priv->remainder) {
-		consume_one(priv, priv->remainder, priv->remainder_size);
-		free(priv->remainder);
-		priv->remainder = NULL;
-		priv->remainder_size = 0;
+	if (priv->remainder.len) {
+		consume_one(priv, priv->remainder.buf, priv->remainder.len);
+		strbuf_reset(&priv->remainder);
 	}
 	return 0;
 }
 
+/*
+ * Trim down common substring at the end of the buffers,
+ * but leave at least ctx lines at the end.
+ */
+static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
+{
+	const int blk = 1024;
+	long trimmed = 0, recovered = 0;
+	char *ap = a->ptr + a->size;
+	char *bp = b->ptr + b->size;
+	long smaller = (a->size < b->size) ? a->size : b->size;
+
+	if (ctx)
+		return;
+
+	while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
+		trimmed += blk;
+		ap -= blk;
+		bp -= blk;
+	}
+
+	while (recovered < trimmed)
+		if (ap[recovered++] == '\n')
+			break;
+	a->size -= trimmed - recovered;
+	b->size -= trimmed - recovered;
+}
+
+int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
+{
+	mmfile_t a = *mf1;
+	mmfile_t b = *mf2;
+
+	trim_common_tail(&a, &b, xecfg->ctxlen);
+
+	return xdl_diff(&a, &b, xpp, xecfg, xecb);
+}
+
+int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
+		  xdiff_emit_consume_fn fn, void *consume_callback_data,
+		  xpparam_t const *xpp,
+		  xdemitconf_t const *xecfg, xdemitcb_t *xecb)
+{
+	int ret;
+	struct xdiff_emit_state state;
+
+	memset(&state, 0, sizeof(state));
+	state.consume = fn;
+	state.consume_callback_data = consume_callback_data;
+	xecb->outf = xdiff_outf;
+	xecb->priv = &state;
+	strbuf_init(&state.remainder, 0);
+	ret = xdi_diff(mf1, mf2, xpp, xecfg, xecb);
+	strbuf_release(&state.remainder);
+	return ret;
+}
+
+struct xdiff_emit_hunk_state {
+	xdiff_emit_hunk_consume_fn consume;
+	void *consume_callback_data;
+};
+
+static int process_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+			xdemitconf_t const *xecfg)
+{
+	long s1, s2, same, p_next, t_next;
+	xdchange_t *xch, *xche;
+	struct xdiff_emit_hunk_state *state = ecb->priv;
+	xdiff_emit_hunk_consume_fn fn = state->consume;
+	void *consume_callback_data = state->consume_callback_data;
+
+	for (xch = xscr; xch; xch = xche->next) {
+		xche = xdl_get_hunk(xch, xecfg);
+
+		s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
+		s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
+		same = s2 + XDL_MAX(xch->i1 - s1, 0);
+		p_next = xche->i1 + xche->chg1;
+		t_next = xche->i2 + xche->chg2;
+
+		fn(consume_callback_data, same, p_next, t_next);
+	}
+	return 0;
+}
+
+int xdi_diff_hunks(mmfile_t *mf1, mmfile_t *mf2,
+		   xdiff_emit_hunk_consume_fn fn, void *consume_callback_data,
+		   xpparam_t const *xpp, xdemitconf_t *xecfg)
+{
+	struct xdiff_emit_hunk_state state;
+	xdemitcb_t ecb;
+
+	memset(&state, 0, sizeof(state));
+	memset(&ecb, 0, sizeof(ecb));
+	state.consume = fn;
+	state.consume_callback_data = consume_callback_data;
+	xecfg->emit_func = (void (*)())process_diff;
+	ecb.priv = &state;
+	return xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
+}
+
 int read_mmfile(mmfile_t *ptr, const char *filename)
 {
 	struct stat st;
@@ -114,8 +210,8 @@ int read_mmfile(mmfile_t *ptr, const char *filename)
 	if ((f = fopen(filename, "rb")) == NULL)
 		return error("Could not open %s", filename);
 	sz = xsize_t(st.st_size);
-	ptr->ptr = xmalloc(sz);
-	if (fread(ptr->ptr, sz, 1, f) != 1)
+	ptr->ptr = xmalloc(sz ? sz : 1);
+	if (sz && fread(ptr->ptr, sz, 1, f) != 1)
 		return error("Could not read %s", filename);
 	fclose(f);
 	ptr->size = sz;
@@ -129,3 +225,105 @@ int buffer_is_binary(const char *ptr, unsigned long size)
 		size = FIRST_FEW_BYTES;
 	return !!memchr(ptr, 0, size);
 }
+
+struct ff_regs {
+	int nr;
+	struct ff_reg {
+		regex_t re;
+		int negate;
+	} *array;
+};
+
+static long ff_regexp(const char *line, long len,
+		char *buffer, long buffer_size, void *priv)
+{
+	char *line_buffer;
+	struct ff_regs *regs = priv;
+	regmatch_t pmatch[2];
+	int i;
+	int result = -1;
+
+	/* Exclude terminating newline (and cr) from matching */
+	if (len > 0 && line[len-1] == '\n') {
+		if (len > 1 && line[len-2] == '\r')
+			len -= 2;
+		else
+			len--;
+	}
+
+	line_buffer = xstrndup(line, len); /* make NUL terminated */
+
+	for (i = 0; i < regs->nr; i++) {
+		struct ff_reg *reg = regs->array + i;
+		if (!regexec(&reg->re, line_buffer, 2, pmatch, 0)) {
+			if (reg->negate)
+				goto fail;
+			break;
+		}
+	}
+	if (regs->nr <= i)
+		goto fail;
+	i = pmatch[1].rm_so >= 0 ? 1 : 0;
+	line += pmatch[i].rm_so;
+	result = pmatch[i].rm_eo - pmatch[i].rm_so;
+	if (result > buffer_size)
+		result = buffer_size;
+	else
+		while (result > 0 && (isspace(line[result - 1])))
+			result--;
+	memcpy(buffer, line, result);
+ fail:
+	free(line_buffer);
+	return result;
+}
+
+void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
+{
+	int i;
+	struct ff_regs *regs;
+
+	xecfg->find_func = ff_regexp;
+	regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
+	for (i = 0, regs->nr = 1; value[i]; i++)
+		if (value[i] == '\n')
+			regs->nr++;
+	regs->array = xmalloc(regs->nr * sizeof(struct ff_reg));
+	for (i = 0; i < regs->nr; i++) {
+		struct ff_reg *reg = regs->array + i;
+		const char *ep = strchr(value, '\n'), *expression;
+		char *buffer = NULL;
+
+		reg->negate = (*value == '!');
+		if (reg->negate && i == regs->nr - 1)
+			die("Last expression must not be negated: %s", value);
+		if (*value == '!')
+			value++;
+		if (ep)
+			expression = buffer = xstrndup(value, ep - value);
+		else
+			expression = value;
+		if (regcomp(&reg->re, expression, cflags))
+			die("Invalid regexp to look for hunk header: %s", expression);
+		free(buffer);
+		value = ep + 1;
+	}
+}
+
+int git_xmerge_style = -1;
+
+int git_xmerge_config(const char *var, const char *value, void *cb)
+{
+	if (!strcasecmp(var, "merge.conflictstyle")) {
+		if (!value)
+			die("'%s' is not a boolean", var);
+		if (!strcmp(value, "diff3"))
+			git_xmerge_style = XDL_MERGE_DIFF3;
+		else if (!strcmp(value, "merge"))
+			git_xmerge_style = 0;
+		else
+			die("unknown style '%s' given for '%s'",
+			    value, var);
+		return 0;
+	}
+	return git_default_config(var, value, cb);
+}