1 files changed, 323 insertions, 0 deletions

diff --git a/third_party/git/xdiff-interface.c b/third_party/git/xdiff-interface.c
new file mode 100644
index 000000000000..4d20069302b2
--- /dev/null
+++ b/third_party/git/xdiff-interface.c
@@ -0,0 +1,323 @@
+#include "cache.h"
+#include "config.h"
+#include "object-store.h"
+#include "xdiff-interface.h"
+#include "xdiff/xtypes.h"
+#include "xdiff/xdiffi.h"
+#include "xdiff/xemit.h"
+#include "xdiff/xmacros.h"
+#include "xdiff/xutils.h"
+
+struct xdiff_emit_state {
+	xdiff_emit_hunk_fn hunk_fn;
+	xdiff_emit_line_fn line_fn;
+	void *consume_callback_data;
+	struct strbuf remainder;
+};
+
+static int xdiff_out_hunk(void *priv_,
+			  long old_begin, long old_nr,
+			  long new_begin, long new_nr,
+			  const char *func, long funclen)
+{
+	struct xdiff_emit_state *priv = priv_;
+
+	if (priv->remainder.len)
+		BUG("xdiff emitted hunk in the middle of a line");
+
+	priv->hunk_fn(priv->consume_callback_data,
+		      old_begin, old_nr, new_begin, new_nr,
+		      func, funclen);
+	return 0;
+}
+
+static void consume_one(void *priv_, char *s, unsigned long size)
+{
+	struct xdiff_emit_state *priv = priv_;
+	char *ep;
+	while (size) {
+		unsigned long this_size;
+		ep = memchr(s, '\n', size);
+		this_size = (ep == NULL) ? size : (ep - s + 1);
+		priv->line_fn(priv->consume_callback_data, s, this_size);
+		size -= this_size;
+		s += this_size;
+	}
+}
+
+static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
+{
+	struct xdiff_emit_state *priv = priv_;
+	int i;
+
+	if (!priv->line_fn)
+		return 0;
+
+	for (i = 0; i < nbuf; i++) {
+		if (mb[i].ptr[mb[i].size-1] != '\n') {
+			/* Incomplete line */
+			strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
+			continue;
+		}
+
+		/* we have a complete line */
+		if (!priv->remainder.len) {
+			consume_one(priv, mb[i].ptr, mb[i].size);
+			continue;
+		}
+		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.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 end on a complete line.
+ */
+static void trim_common_tail(mmfile_t *a, mmfile_t *b)
+{
+	const int blk = 1024;
+	long trimmed = 0, recovered = 0;
+	char *ap = a->size ? a->ptr + a->size : a->ptr;
+	char *bp = b->size ? b->ptr + b->size : b->ptr;
+	long smaller = (a->size < b->size) ? a->size : b->size;
+
+	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;
+
+	if (mf1->size > MAX_XDIFF_SIZE || mf2->size > MAX_XDIFF_SIZE)
+		return -1;
+
+	if (!xecfg->ctxlen && !(xecfg->flags & XDL_EMIT_FUNCCONTEXT))
+		trim_common_tail(&a, &b);
+
+	return xdl_diff(&a, &b, xpp, xecfg, xecb);
+}
+
+void discard_hunk_line(void *priv,
+		       long ob, long on, long nb, long nn,
+		       const char *func, long funclen)
+{
+}
+
+int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
+		  xdiff_emit_hunk_fn hunk_fn,
+		  xdiff_emit_line_fn line_fn,
+		  void *consume_callback_data,
+		  xpparam_t const *xpp, xdemitconf_t const *xecfg)
+{
+	int ret;
+	struct xdiff_emit_state state;
+	xdemitcb_t ecb;
+
+	memset(&state, 0, sizeof(state));
+	state.hunk_fn = hunk_fn;
+	state.line_fn = line_fn;
+	state.consume_callback_data = consume_callback_data;
+	memset(&ecb, 0, sizeof(ecb));
+	if (hunk_fn)
+		ecb.out_hunk = xdiff_out_hunk;
+	ecb.out_line = xdiff_outf;
+	ecb.priv = &state;
+	strbuf_init(&state.remainder, 0);
+	ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
+	strbuf_release(&state.remainder);
+	return ret;
+}
+
+int read_mmfile(mmfile_t *ptr, const char *filename)
+{
+	struct stat st;
+	FILE *f;
+	size_t sz;
+
+	if (stat(filename, &st))
+		return error_errno("Could not stat %s", filename);
+	if ((f = fopen(filename, "rb")) == NULL)
+		return error_errno("Could not open %s", filename);
+	sz = xsize_t(st.st_size);
+	ptr->ptr = xmalloc(sz ? sz : 1);
+	if (sz && fread(ptr->ptr, sz, 1, f) != 1) {
+		fclose(f);
+		return error("Could not read %s", filename);
+	}
+	fclose(f);
+	ptr->size = sz;
+	return 0;
+}
+
+void read_mmblob(mmfile_t *ptr, const struct object_id *oid)
+{
+	unsigned long size;
+	enum object_type type;
+
+	if (oideq(oid, &null_oid)) {
+		ptr->ptr = xstrdup("");
+		ptr->size = 0;
+		return;
+	}
+
+	ptr->ptr = read_object_file(oid, &type, &size);
+	if (!ptr->ptr || type != OBJ_BLOB)
+		die("unable to read blob object %s", oid_to_hex(oid));
+	ptr->size = size;
+}
+
+#define FIRST_FEW_BYTES 8000
+int buffer_is_binary(const char *ptr, unsigned long size)
+{
+	if (FIRST_FEW_BYTES < 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)
+{
+	struct ff_regs *regs = priv;
+	regmatch_t pmatch[2];
+	int i;
+	int result;
+
+	/* 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--;
+	}
+
+	for (i = 0; i < regs->nr; i++) {
+		struct ff_reg *reg = regs->array + i;
+		if (!regexec_buf(&reg->re, line, len, 2, pmatch, 0)) {
+			if (reg->negate)
+				return -1;
+			break;
+		}
+	}
+	if (regs->nr <= i)
+		return -1;
+	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;
+	while (result > 0 && (isspace(line[result - 1])))
+		result--;
+	memcpy(buffer, line, result);
+	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++;
+	ALLOC_ARRAY(regs->array, regs->nr);
+	for (i = 0; i < regs->nr; i++) {
+		struct ff_reg *reg = regs->array + i;
+		const char *ep, *expression;
+		char *buffer = NULL;
+
+		if (!value)
+			BUG("mismatch between line count and parsing");
+		ep = strchr(value, '\n');
+
+		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 ? ep + 1 : NULL;
+	}
+}
+
+void xdiff_clear_find_func(xdemitconf_t *xecfg)
+{
+	if (xecfg->find_func) {
+		int i;
+		struct ff_regs *regs = xecfg->find_func_priv;
+
+		for (i = 0; i < regs->nr; i++)
+			regfree(&regs->array[i].re);
+		free(regs->array);
+		free(regs);
+		xecfg->find_func = NULL;
+		xecfg->find_func_priv = NULL;
+	}
+}
+
+unsigned long xdiff_hash_string(const char *s, size_t len, long flags)
+{
+	return xdl_hash_record(&s, s + len, flags);
+}
+
+int xdiff_compare_lines(const char *l1, long s1,
+			const char *l2, long s2, long flags)
+{
+	return xdl_recmatch(l1, s1, l2, s2, flags);
+}
+
+int git_xmerge_style = -1;
+
+int git_xmerge_config(const char *var, const char *value, void *cb)
+{
+	if (!strcmp(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;
+		/*
+		 * Please update _git_checkout() in
+		 * git-completion.bash when you add new merge config
+		 */
+		else
+			die("unknown style '%s' given for '%s'",
+			    value, var);
+		return 0;
+	}
+	return git_default_config(var, value, cb);
+}