xdiff-interface.c - jrn/git - Git at Google

 #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 int consume_one(void *priv_, char *s, unsigned long size)
 {
 	struct xdiff_emit_state *priv = priv_;
 	char *ep;
 	while (size) {
 		unsigned long this_size;
 		int ret;
 		ep = memchr(s, '\n', size);
 		this_size = (ep == NULL) ? size : (ep - s + 1);
 		ret = priv->line_fn(priv->consume_callback_data, s, this_size);
 		if (ret)
 			return ret;
 		size -= this_size;
 		s += this_size;
 	}
 	return 0;
 }

 static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
 {
 	struct xdiff_emit_state *priv = priv_;
 	int i;
 	int stop = 0;

 	if (!priv->line_fn)
 		return 0;

 	for (i = 0; i < nbuf; i++) {
 		if (stop)
 			return 1;
 		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) {
 			stop = consume_one(priv, mb[i].ptr, mb[i].size);
 			continue;
 		}
 		strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
 		stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
 		strbuf_reset(&priv->remainder);
 	}
 	if (stop)
 		return -1;
 	if (priv->remainder.len) {
 		stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
 		strbuf_reset(&priv->remainder);
 	}
 	if (stop)
 		return -1;
 	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);
 }

 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);
 }
	#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 int consume_one(void priv_, char s, unsigned long size)
	{
	struct xdiff_emit_state *priv = priv_;
	char *ep;
	while (size) {
	unsigned long this_size;
	int ret;
	ep = memchr(s, '\n', size);
	this_size = (ep == NULL) ? size : (ep - s + 1);
	ret = priv->line_fn(priv->consume_callback_data, s, this_size);
	if (ret)
	return ret;
	size -= this_size;
	s += this_size;
	}
	return 0;
	}

	static int xdiff_outf(void priv_, mmbuffer_t mb, int nbuf)
	{
	struct xdiff_emit_state *priv = priv_;
	int i;
	int stop = 0;

	if (!priv->line_fn)
	return 0;

	for (i = 0; i < nbuf; i++) {
	if (stop)
	return 1;
	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) {
	stop = consume_one(priv, mb[i].ptr, mb[i].size);
	continue;
	}
	strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
	stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
	strbuf_reset(&priv->remainder);
	}
	if (stop)
	return -1;
	if (priv->remainder.len) {
	stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
	strbuf_reset(&priv->remainder);
	}
	if (stop)
	return -1;
	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);
	}

	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);
	}