thodg/libgit2/src/diff_xdiff.c

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• Hash : 0c7f49dd
  Author :
  Date : 2017-06-30T13:39:01
  

  Make sure to always include "common.h" first
  
  Next to including several files, our "common.h" header also declares
  various macros which are then used throughout the project. As such, we
  have to make sure to always include this file first in all
  implementation files. Otherwise, we might encounter problems or even
  silent behavioural differences due to macros or defines not being
  defined as they should be. So in fact, our header and implementation
  files should make sure to always include "common.h" first.
  
  This commit does so by establishing a common include pattern. Header
  files inside of "src" will now always include "common.h" as its first
  other file, separated by a newline from all the other includes to make
  it stand out as special. There are two cases for the implementation
  files. If they do have a matching header file, they will always include
  this one first, leading to "common.h" being transitively included as
  first file. If they do not have a matching header file, they instead
  include "common.h" as first file themselves.
  
  This fixes the outlined problems and will become our standard practice
  for header and source files inside of the "src/" from now on.
  

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• src/diff_xdiff.c

• /*
   * 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 "diff_xdiff.h"
  
  #include "git2/errors.h"
  #include "diff.h"
  #include "diff_driver.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;
  }
  

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