src/diff_xdiff.c - third_party/libgit2 - Git at Google

 /*
  * Copyright (C) the libgit2 contributors. All rights reserved.
  *
  * This file is part of libgit2, distributed under the GNU GPL v2 with
  * a Linking Exception. For full terms see the included COPYING file.
  */
 #include "git2/errors.h"
 #include "common.h"
 #include "diff.h"
 #include "diff_driver.h"
 #include "diff_xdiff.h"
 #include "patch_generate.h"

 static int git_xdiff_scan_int(const char **str, int *value)
 {
 	const char *scan = *str;
 	int v = 0, digits = 0;
 	/* find next digit */
 	for (scan = *str; *scan && !git__isdigit(*scan); scan++);
 	/* parse next number */
 	for (; git__isdigit(*scan); scan++, digits++)
 		v = (v * 10) + (*scan - '0');
 	*str = scan;
 	*value = v;
 	return (digits > 0) ? 0 : -1;
 }

 static int git_xdiff_parse_hunk(git_diff_hunk *hunk, const char *header)
 {
 	/* expect something of the form "@@ -%d[,%d] +%d[,%d] @@" */
 	if (*header != '@')
 		goto fail;
 	if (git_xdiff_scan_int(&header, &hunk->old_start) < 0)
 		goto fail;
 	if (*header == ',') {
 		if (git_xdiff_scan_int(&header, &hunk->old_lines) < 0)
 			goto fail;
 	} else
 		hunk->old_lines = 1;
 	if (git_xdiff_scan_int(&header, &hunk->new_start) < 0)
 		goto fail;
 	if (*header == ',') {
 		if (git_xdiff_scan_int(&header, &hunk->new_lines) < 0)
 			goto fail;
 	} else
 		hunk->new_lines = 1;
 	if (hunk->old_start < 0 || hunk->new_start < 0)
 		goto fail;

 	return 0;

 fail:
 	giterr_set(GITERR_INVALID, "malformed hunk header from xdiff");
 	return -1;
 }

 typedef struct {
 	git_xdiff_output *xo;
 	git_patch_generated *patch;
 	git_diff_hunk hunk;
 	int old_lineno, new_lineno;
 	mmfile_t xd_old_data, xd_new_data;
 } git_xdiff_info;

 static int diff_update_lines(
 	git_xdiff_info *info,
 	git_diff_line *line,
 	const char *content,
 	size_t content_len)
 {
 	const char *scan = content, *scan_end = content + content_len;

 	for (line->num_lines = 0; scan < scan_end; ++scan)
 		if (*scan == '\n')
 			++line->num_lines;

 	line->content     = content;
 	line->content_len = content_len;

 	/* expect " "/"-"/"+", then data */
 	switch (line->origin) {
 	case GIT_DIFF_LINE_ADDITION:
 	case GIT_DIFF_LINE_DEL_EOFNL:
 		line->old_lineno = -1;
 		line->new_lineno = info->new_lineno;
 		info->new_lineno += (int)line->num_lines;
 		break;
 	case GIT_DIFF_LINE_DELETION:
 	case GIT_DIFF_LINE_ADD_EOFNL:
 		line->old_lineno = info->old_lineno;
 		line->new_lineno = -1;
 		info->old_lineno += (int)line->num_lines;
 		break;
 	case GIT_DIFF_LINE_CONTEXT:
 	case GIT_DIFF_LINE_CONTEXT_EOFNL:
 		line->old_lineno = info->old_lineno;
 		line->new_lineno = info->new_lineno;
 		info->old_lineno += (int)line->num_lines;
 		info->new_lineno += (int)line->num_lines;
 		break;
 	default:
 		giterr_set(GITERR_INVALID, "unknown diff line origin %02x",
 			(unsigned int)line->origin);
 		return -1;
 	}

 	return 0;
 }

 static int git_xdiff_cb(void *priv, mmbuffer_t *bufs, int len)
 {
 	git_xdiff_info *info = priv;
 	git_patch_generated *patch = info->patch;
 	const git_diff_delta *delta = patch->base.delta;
 	git_patch_generated_output *output = &info->xo->output;
 	git_diff_line line;

 	if (len == 1) {
 		output->error = git_xdiff_parse_hunk(&info->hunk, bufs[0].ptr);
 		if (output->error < 0)
 			return output->error;

 		info->hunk.header_len = bufs[0].size;
 		if (info->hunk.header_len >= sizeof(info->hunk.header))
 			info->hunk.header_len = sizeof(info->hunk.header) - 1;
 		memcpy(info->hunk.header, bufs[0].ptr, info->hunk.header_len);
 		info->hunk.header[info->hunk.header_len] = '\0';

 		if (output->hunk_cb != NULL &&
 			(output->error = output->hunk_cb(
 				delta, &info->hunk, output->payload)))
 			return output->error;

 		info->old_lineno = info->hunk.old_start;
 		info->new_lineno = info->hunk.new_start;
 	}

 	if (len == 2 || len == 3) {
 		/* expect " "/"-"/"+", then data */
 		line.origin =
 			(*bufs[0].ptr == '+') ? GIT_DIFF_LINE_ADDITION :
 			(*bufs[0].ptr == '-') ? GIT_DIFF_LINE_DELETION :
 			GIT_DIFF_LINE_CONTEXT;

 		if (line.origin == GIT_DIFF_LINE_ADDITION)
 			line.content_offset = bufs[1].ptr - info->xd_new_data.ptr;
 		else if (line.origin == GIT_DIFF_LINE_DELETION)
 			line.content_offset = bufs[1].ptr - info->xd_old_data.ptr;
 		else
 			line.content_offset = -1;

 		output->error = diff_update_lines(
 			info, &line, bufs[1].ptr, bufs[1].size);

 		if (!output->error && output->data_cb != NULL)
 			output->error = output->data_cb(
 				delta, &info->hunk, &line, output->payload);
 	}

 	if (len == 3 && !output->error) {
 		/* If we have a '+' and a third buf, then we have added a line
 		 * without a newline and the old code had one, so DEL_EOFNL.
 		 * If we have a '-' and a third buf, then we have removed a line
 		 * with out a newline but added a blank line, so ADD_EOFNL.
 		 */
 		line.origin =
 			(*bufs[0].ptr == '+') ? GIT_DIFF_LINE_DEL_EOFNL :
 			(*bufs[0].ptr == '-') ? GIT_DIFF_LINE_ADD_EOFNL :
 			GIT_DIFF_LINE_CONTEXT_EOFNL;

 		line.content_offset = -1;

 		output->error = diff_update_lines(
 			info, &line, bufs[2].ptr, bufs[2].size);

 		if (!output->error && output->data_cb != NULL)
 			output->error = output->data_cb(
 				delta, &info->hunk, &line, output->payload);
 	}

 	return output->error;
 }

 static int git_xdiff(git_patch_generated_output *output, git_patch_generated *patch)
 {
 	git_xdiff_output *xo = (git_xdiff_output *)output;
 	git_xdiff_info info;
 	git_diff_find_context_payload findctxt;

 	memset(&info, 0, sizeof(info));
 	info.patch = patch;
 	info.xo    = xo;

 	xo->callback.priv = &info;

 	git_diff_find_context_init(
 		&xo->config.find_func, &findctxt, git_patch_generated_driver(patch));
 	xo->config.find_func_priv = &findctxt;

 	if (xo->config.find_func != NULL)
 		xo->config.flags |= XDL_EMIT_FUNCNAMES;
 	else
 		xo->config.flags &= ~XDL_EMIT_FUNCNAMES;

 	/* TODO: check ofile.opts_flags to see if driver-specific per-file
 	 * updates are needed to xo->params.flags
 	 */

 	git_patch_generated_old_data(&info.xd_old_data.ptr, &info.xd_old_data.size, patch);
 	git_patch_generated_new_data(&info.xd_new_data.ptr, &info.xd_new_data.size, patch);

 	if (info.xd_old_data.size > GIT_XDIFF_MAX_SIZE ||
 		info.xd_new_data.size > GIT_XDIFF_MAX_SIZE) {
 		giterr_set(GITERR_INVALID, "files too large for diff");
 		return -1;
 	}

 	xdl_diff(&info.xd_old_data, &info.xd_new_data,
 		&xo->params, &xo->config, &xo->callback);

 	git_diff_find_context_clear(&findctxt);

 	return xo->output.error;
 }

 void git_xdiff_init(git_xdiff_output *xo, const git_diff_options *opts)
 {
 	uint32_t flags = opts ? opts->flags : 0;

 	xo->output.diff_cb = git_xdiff;

 	xo->config.ctxlen = opts ? opts->context_lines : 3;
 	xo->config.interhunkctxlen = opts ? opts->interhunk_lines : 0;

 	if (flags & GIT_DIFF_IGNORE_WHITESPACE)
 		xo->params.flags |= XDF_WHITESPACE_FLAGS;
 	if (flags & GIT_DIFF_IGNORE_WHITESPACE_CHANGE)
 		xo->params.flags |= XDF_IGNORE_WHITESPACE_CHANGE;
 	if (flags & GIT_DIFF_IGNORE_WHITESPACE_EOL)
 		xo->params.flags |= XDF_IGNORE_WHITESPACE_AT_EOL;

 	if (flags & GIT_DIFF_PATIENCE)
 		xo->params.flags |= XDF_PATIENCE_DIFF;
 	if (flags & GIT_DIFF_MINIMAL)
 		xo->params.flags |= XDF_NEED_MINIMAL;

 	xo->callback.outf = git_xdiff_cb;
 }
	/*
	* Copyright (C) the libgit2 contributors. All rights reserved.
	*
	* This file is part of libgit2, distributed under the GNU GPL v2 with
	* a Linking Exception. For full terms see the included COPYING file.
	*/
	#include "git2/errors.h"
	#include "common.h"
	#include "diff.h"
	#include "diff_driver.h"
	#include "diff_xdiff.h"
	#include "patch_generate.h"

	static int git_xdiff_scan_int(const char *str, int value)
	{
	const char scan = str;
	int v = 0, digits = 0;
	/* find next digit */
	for (scan = str; scan && !git__isdigit(*scan); scan++);
	/* parse next number */
	for (; git__isdigit(*scan); scan++, digits++)
	v = (v * 10) + (*scan - '0');
	*str = scan;
	*value = v;
	return (digits > 0) ? 0 : -1;
	}

	static int git_xdiff_parse_hunk(git_diff_hunk hunk, const char header)
	{
	/* expect something of the form "@@ -%d[,%d] +%d[,%d] @@" */
	if (*header != '@')
	goto fail;
	if (git_xdiff_scan_int(&header, &hunk->old_start) < 0)
	goto fail;
	if (*header == ',') {
	if (git_xdiff_scan_int(&header, &hunk->old_lines) < 0)
	goto fail;
	} else
	hunk->old_lines = 1;
	if (git_xdiff_scan_int(&header, &hunk->new_start) < 0)
	goto fail;
	if (*header == ',') {
	if (git_xdiff_scan_int(&header, &hunk->new_lines) < 0)
	goto fail;
	} else
	hunk->new_lines = 1;
	if (hunk->old_start < 0 \|\| hunk->new_start < 0)
	goto fail;

	return 0;

	fail:
	giterr_set(GITERR_INVALID, "malformed hunk header from xdiff");
	return -1;
	}

	typedef struct {
	git_xdiff_output *xo;
	git_patch_generated *patch;
	git_diff_hunk hunk;
	int old_lineno, new_lineno;
	mmfile_t xd_old_data, xd_new_data;
	} git_xdiff_info;

	static int diff_update_lines(
	git_xdiff_info *info,
	git_diff_line *line,
	const char *content,
	size_t content_len)
	{
	const char scan = content, scan_end = content + content_len;

	for (line->num_lines = 0; scan < scan_end; ++scan)
	if (*scan == '\n')
	++line->num_lines;

	line->content = content;
	line->content_len = content_len;

	/* expect " "/"-"/"+", then data */
	switch (line->origin) {
	case GIT_DIFF_LINE_ADDITION:
	case GIT_DIFF_LINE_DEL_EOFNL:
	line->old_lineno = -1;
	line->new_lineno = info->new_lineno;
	info->new_lineno += (int)line->num_lines;
	break;
	case GIT_DIFF_LINE_DELETION:
	case GIT_DIFF_LINE_ADD_EOFNL:
	line->old_lineno = info->old_lineno;
	line->new_lineno = -1;
	info->old_lineno += (int)line->num_lines;
	break;
	case GIT_DIFF_LINE_CONTEXT:
	case GIT_DIFF_LINE_CONTEXT_EOFNL:
	line->old_lineno = info->old_lineno;
	line->new_lineno = info->new_lineno;
	info->old_lineno += (int)line->num_lines;
	info->new_lineno += (int)line->num_lines;
	break;
	default:
	giterr_set(GITERR_INVALID, "unknown diff line origin %02x",
	(unsigned int)line->origin);
	return -1;
	}

	return 0;
	}

	static int git_xdiff_cb(void priv, mmbuffer_t bufs, int len)
	{
	git_xdiff_info *info = priv;
	git_patch_generated *patch = info->patch;
	const git_diff_delta *delta = patch->base.delta;
	git_patch_generated_output *output = &info->xo->output;
	git_diff_line line;

	if (len == 1) {
	output->error = git_xdiff_parse_hunk(&info->hunk, bufs[0].ptr);
	if (output->error < 0)
	return output->error;

	info->hunk.header_len = bufs[0].size;
	if (info->hunk.header_len >= sizeof(info->hunk.header))
	info->hunk.header_len = sizeof(info->hunk.header) - 1;
	memcpy(info->hunk.header, bufs[0].ptr, info->hunk.header_len);
	info->hunk.header[info->hunk.header_len] = '\0';

	if (output->hunk_cb != NULL &&
	(output->error = output->hunk_cb(
	delta, &info->hunk, output->payload)))
	return output->error;

	info->old_lineno = info->hunk.old_start;
	info->new_lineno = info->hunk.new_start;
	}

	if (len == 2 \|\| len == 3) {
	/* expect " "/"-"/"+", then data */
	line.origin =
	(*bufs[0].ptr == '+') ? GIT_DIFF_LINE_ADDITION :
	(*bufs[0].ptr == '-') ? GIT_DIFF_LINE_DELETION :
	GIT_DIFF_LINE_CONTEXT;

	if (line.origin == GIT_DIFF_LINE_ADDITION)
	line.content_offset = bufs[1].ptr - info->xd_new_data.ptr;
	else if (line.origin == GIT_DIFF_LINE_DELETION)
	line.content_offset = bufs[1].ptr - info->xd_old_data.ptr;
	else
	line.content_offset = -1;

	output->error = diff_update_lines(
	info, &line, bufs[1].ptr, bufs[1].size);

	if (!output->error && output->data_cb != NULL)
	output->error = output->data_cb(
	delta, &info->hunk, &line, output->payload);
	}

	if (len == 3 && !output->error) {
	/* If we have a '+' and a third buf, then we have added a line
	* without a newline and the old code had one, so DEL_EOFNL.
	* If we have a '-' and a third buf, then we have removed a line
	* with out a newline but added a blank line, so ADD_EOFNL.
	*/
	line.origin =
	(*bufs[0].ptr == '+') ? GIT_DIFF_LINE_DEL_EOFNL :
	(*bufs[0].ptr == '-') ? GIT_DIFF_LINE_ADD_EOFNL :
	GIT_DIFF_LINE_CONTEXT_EOFNL;

	line.content_offset = -1;

	output->error = diff_update_lines(
	info, &line, bufs[2].ptr, bufs[2].size);

	if (!output->error && output->data_cb != NULL)
	output->error = output->data_cb(
	delta, &info->hunk, &line, output->payload);
	}

	return output->error;
	}

	static int git_xdiff(git_patch_generated_output output, git_patch_generated patch)
	{
	git_xdiff_output xo = (git_xdiff_output )output;
	git_xdiff_info info;
	git_diff_find_context_payload findctxt;

	memset(&info, 0, sizeof(info));
	info.patch = patch;
	info.xo = xo;

	xo->callback.priv = &info;

	git_diff_find_context_init(
	&xo->config.find_func, &findctxt, git_patch_generated_driver(patch));
	xo->config.find_func_priv = &findctxt;

	if (xo->config.find_func != NULL)
	xo->config.flags \|= XDL_EMIT_FUNCNAMES;
	else
	xo->config.flags &= ~XDL_EMIT_FUNCNAMES;

	/* TODO: check ofile.opts_flags to see if driver-specific per-file
	* updates are needed to xo->params.flags
	*/

	git_patch_generated_old_data(&info.xd_old_data.ptr, &info.xd_old_data.size, patch);
	git_patch_generated_new_data(&info.xd_new_data.ptr, &info.xd_new_data.size, patch);

	if (info.xd_old_data.size > GIT_XDIFF_MAX_SIZE \|\|
	info.xd_new_data.size > GIT_XDIFF_MAX_SIZE) {
	giterr_set(GITERR_INVALID, "files too large for diff");
	return -1;
	}

	xdl_diff(&info.xd_old_data, &info.xd_new_data,
	&xo->params, &xo->config, &xo->callback);

	git_diff_find_context_clear(&findctxt);

	return xo->output.error;
	}

	void git_xdiff_init(git_xdiff_output xo, const git_diff_options opts)
	{
	uint32_t flags = opts ? opts->flags : 0;

	xo->output.diff_cb = git_xdiff;

	xo->config.ctxlen = opts ? opts->context_lines : 3;
	xo->config.interhunkctxlen = opts ? opts->interhunk_lines : 0;

	if (flags & GIT_DIFF_IGNORE_WHITESPACE)
	xo->params.flags \|= XDF_WHITESPACE_FLAGS;
	if (flags & GIT_DIFF_IGNORE_WHITESPACE_CHANGE)
	xo->params.flags \|= XDF_IGNORE_WHITESPACE_CHANGE;
	if (flags & GIT_DIFF_IGNORE_WHITESPACE_EOL)
	xo->params.flags \|= XDF_IGNORE_WHITESPACE_AT_EOL;

	if (flags & GIT_DIFF_PATIENCE)
	xo->params.flags \|= XDF_PATIENCE_DIFF;
	if (flags & GIT_DIFF_MINIMAL)
	xo->params.flags \|= XDF_NEED_MINIMAL;

	xo->callback.outf = git_xdiff_cb;
	}