thodg/libgit2/src/fetch.c

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• 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.
  

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• src/fetch.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 "git2/oid.h"
  #include "git2/refs.h"
  #include "git2/revwalk.h"
  #include "git2/transport.h"
  
  #include "common.h"
  #include "remote.h"
  #include "refspec.h"
  #include "pack.h"
  #include "fetch.h"
  #include "netops.h"
  #include "repository.h"
  #include "refs.h"
  
  static int maybe_want(git_remote *remote, git_remote_head *head, git_odb *odb, git_refspec *tagspec)
  {
  	int match = 0;
  
  	if (!git_reference_is_valid_name(head->name))
  		return 0;
  
  	if (remote->download_tags == GIT_REMOTE_DOWNLOAD_TAGS_ALL) {
  		/*
  		 * If tagopt is --tags, then we only use the default
  		 * tags refspec and ignore the remote's
  		 */
  		if (git_refspec_src_matches(tagspec, head->name))
  			match = 1;
  		else
  			return 0;
  	} else if (git_remote__matching_refspec(remote, head->name))
  			match = 1;
  
  	if (!match)
  		return 0;
  
  	/* If we have the object, mark it so we don't ask for it */
  	if (git_odb_exists(odb, &head->oid))
  		head->local = 1;
  	else
  		remote->need_pack = 1;
  
  	return git_vector_insert(&remote->refs, head);
  }
  
  static int filter_wants(git_remote *remote)
  {
  	git_remote_head **heads;
  	git_refspec tagspec, head;
  	int error = 0;
  	git_odb *odb;
  	size_t i, heads_len;
  
  	git_vector_clear(&remote->refs);
  	if ((error = git_refspec__parse(&tagspec, GIT_REFSPEC_TAGS, true)) < 0)
  		return error;
  
  	/*
  	 * The fetch refspec can be NULL, and what this means is that the
  	 * user didn't specify one. This is fine, as it means that we're
  	 * not interested in any particular branch but just the remote's
  	 * HEAD, which will be stored in FETCH_HEAD after the fetch.
  	 */
  	if (remote->active_refspecs.length == 0) {
  		if ((error = git_refspec__parse(&head, "HEAD", true)) < 0)
  			goto cleanup;
  
  		error = git_refspec__dwim_one(&remote->active_refspecs, &head, &remote->refs);
  		git_refspec__free(&head);
  
  		if (error < 0)
  			goto cleanup;
  	}
  
  	if (git_repository_odb__weakptr(&odb, remote->repo) < 0)
  		goto cleanup;
  
  	if (git_remote_ls((const git_remote_head ***)&heads, &heads_len, remote) < 0)
  		goto cleanup;
  
  	for (i = 0; i < heads_len; i++) {
  		if ((error = maybe_want(remote, heads[i], odb, &tagspec)) < 0)
  			break;
  	}
  
  cleanup:
  	git_refspec__free(&tagspec);
  
  	return error;
  }
  
  /*
   * In this first version, we push all our refs in and start sending
   * them out. When we get an ACK we hide that commit and continue
   * traversing until we're done
   */
  int git_fetch_negotiate(git_remote *remote)
  {
  	git_transport *t = remote->transport;
  
  	if (filter_wants(remote) < 0) {
  		giterr_set(GITERR_NET, "Failed to filter the reference list for wants");
  		return -1;
  	}
  
  	/* Don't try to negotiate when we don't want anything */
  	if (!remote->need_pack)
  		return 0;
  
  	/*
  	 * Now we have everything set up so we can start tell the
  	 * server what we want and what we have.
  	 */
  	return t->negotiate_fetch(t,
  		remote->repo,
  		(const git_remote_head * const *)remote->refs.contents,
  		remote->refs.length);
  }
  
  int git_fetch_download_pack(git_remote *remote)
  {
  	git_transport *t = remote->transport;
  
  	if (!remote->need_pack)
  		return 0;
  
  	return t->download_pack(t, remote->repo, &remote->stats,
  			remote->callbacks.transfer_progress, remote->callbacks.payload);
  }
  

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