thodg/libgit2/src/diff_xdiff.c

• Show log

  Commit

• Hash : 25e0b157
  Author :
  Date : 2013-12-06T15:07:57
  

  Remove converting user error to GIT_EUSER
  
  This changes the behavior of callbacks so that the callback error
  code is not converted into GIT_EUSER and instead we propagate the
  return value through to the caller.  Instead of using the
  giterr_capture and giterr_restore functions, we now rely on all
  functions to pass back the return value from a callback.
  
  To avoid having a return value with no error message, the user
  can call the public giterr_set_str or some such function to set
  an error message.  There is a new helper 'giterr_set_callback'
  that functions can invoke after making a callback which ensures
  that some error message was set in case the callback did not set
  one.
  
  In places where the sign of the callback return value is
  meaningful (e.g. positive to skip, negative to abort), only the
  negative values are returned back to the caller, obviously, since
  the other values allow for continuing the loop.
  
  The hardest parts of this were in the checkout code where positive
  return values were overloaded as meaningful values for checkout.
  I fixed this by adding an output parameter to many of the internal
  checkout functions and removing the overload.  This added some
  code, but it is probably a better implementation.
  
  There is some funkiness in the network code where user provided
  callbacks could be returning a positive or a negative value and
  we want to rely on that to cancel the loop.  There are still a
  couple places where an user error might get turned into GIT_EUSER
  there, I think, though none exercised by the tests.
  

Download

• 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 "common.h"
  #include "diff.h"
  #include "diff_driver.h"
  #include "diff_patch.h"
  #include "diff_xdiff.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 *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 *patch = info->patch;
  	const git_diff_delta *delta = git_patch_get_delta(patch);
  	git_diff_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_diff_output *output, git_patch *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__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__old_data(&info.xd_old_data.ptr, &info.xd_old_data.size, patch);
  	git_patch__new_data(&info.xd_new_data.ptr, &info.xd_new_data.size, patch);
  
  	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;
  }
  

Download