thodg/libgit2/src/fetch.c

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• Hash : 97769280
  Author :
  Date : 2011-11-30T11:27:15
  

  Use git_buf for path storage instead of stack-based buffers This converts virtually all of the places that allocate GIT_PATH_MAX buffers on the stack for manipulating paths to use git_buf objects instead. The patch is pretty careful not to touch the public API for libgit2, so there are a few places that still use GIT_PATH_MAX. This extends and changes some details of the git_buf implementation to add a couple of extra functions and to make error handling easier. This includes serious alterations to all the path.c functions, and several of the fileops.c ones, too. Also, there are a number of new functions that parallel existing ones except that use a git_buf instead of a stack-based buffer (such as git_config_find_global_r that exists alongsize git_config_find_global). This also modifies the win32 version of p_realpath to allocate whatever buffer size is needed to accommodate the realpath instead of hardcoding a GIT_PATH_MAX limit, but that change needs to be tested still.

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• src/fetch.c

• /*
   * Copyright (C) 2009-2011 the libgit2 contributors
   *
   * 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/remote.h"
  #include "git2/oid.h"
  #include "git2/refs.h"
  #include "git2/revwalk.h"
  
  #include "common.h"
  #include "transport.h"
  #include "remote.h"
  #include "refspec.h"
  #include "pack.h"
  #include "fetch.h"
  #include "netops.h"
  
  struct filter_payload {
  	git_remote *remote;
  	const git_refspec *spec;
  	git_odb *odb;
  	int found_head;
  };
  
  static int filter_ref__cb(git_remote_head *head, void *payload)
  {
  	struct filter_payload *p = payload;
  	int error;
  
  	if (!p->found_head && strcmp(head->name, GIT_HEAD_FILE) == 0) {
  		p->found_head = 1;
  	} else {
  		/* If it doesn't match the refpec, we don't want it */
  		error = git_refspec_src_match(p->spec, head->name);
  
  		if (error == GIT_ENOMATCH)
  			return GIT_SUCCESS;
  
  		if (error < GIT_SUCCESS)
  			return git__rethrow(error, "Error matching remote ref name");
  	}
  
  	/* If we have the object, mark it so we don't ask for it */
  	if (git_odb_exists(p->odb, &head->oid))
  		head->local = 1;
  	else
  		p->remote->need_pack = 1;
  
  	return git_vector_insert(&p->remote->refs, head);
  }
  
  static int filter_wants(git_remote *remote)
  {
  	int error;
  	struct filter_payload p;
  
  	git_vector_clear(&remote->refs);
  
  	/*
  	 * 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.
  	 */
  	p.spec = git_remote_fetchspec(remote);
  	p.found_head = 0;
  	p.remote = remote;
  
  	error = git_repository_odb__weakptr(&p.odb, remote->repo);
  	if (error < GIT_SUCCESS)
  		return error;
  
  	return remote->transport->ls(remote->transport, &filter_ref__cb, &p);
  }
  
  /*
   * 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)
  {
  	int error;
  	git_transport *t = remote->transport;
  
  	error = filter_wants(remote);
  	if (error < GIT_SUCCESS)
  		return git__rethrow(error, "Failed to filter the reference list for wants");
  
  	/* Don't try to negotiate when we don't want anything */
  	if (remote->refs.length == 0)
  		return GIT_SUCCESS;
  
  	if (!remote->need_pack)
  		return GIT_SUCCESS;
  
  	/*
  	 * 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, &remote->refs);
  }
  
  int git_fetch_download_pack(char **out, git_remote *remote)
  {
  	if(!remote->need_pack) {
  		*out = NULL;
  		return GIT_SUCCESS;
  	}
  
  	return remote->transport->download_pack(out, remote->transport, remote->repo);
  }
  
  /* Receiving data from a socket and storing it is pretty much the same for git and HTTP */
  int git_fetch__download_pack(
  	char **out,
  	const char *buffered,
  	size_t buffered_size,
  	GIT_SOCKET fd,
  	git_repository *repo)
  {
  	git_filebuf file = GIT_FILEBUF_INIT;
  	int error;
  	char buff[1024];
  	git_buf path = GIT_BUF_INIT;
  	static const char suff[] = "/objects/pack/pack-received";
  	gitno_buffer buf;
  
  	gitno_buffer_setup(&buf, buff, sizeof(buff), fd);
  
  	if (memcmp(buffered, "PACK", strlen("PACK"))) {
  		return git__throw(GIT_ERROR, "The pack doesn't start with the signature");
  	}
  
  	error = git_buf_joinpath(&path, repo->path_repository, suff);
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	error = git_filebuf_open(&file, path.ptr, GIT_FILEBUF_TEMPORARY);
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	/* Part of the packfile has been received, don't loose it */
  	error = git_filebuf_write(&file, buffered, buffered_size);
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	while (1) {
  		error = git_filebuf_write(&file, buf.data, buf.offset);
  		if (error < GIT_SUCCESS)
  			goto cleanup;
  
  		gitno_consume_n(&buf, buf.offset);
  		error = gitno_recv(&buf);
  		if (error < GIT_SUCCESS)
  			goto cleanup;
  		if (error == 0) /* Orderly shutdown */
  			break;
  	}
  
  	*out = git__strdup(file.path_lock);
  	if (*out == NULL) {
  		error = GIT_ENOMEM;
  		goto cleanup;
  	}
  
  	/* A bit dodgy, but we need to keep the pack at the temporary path */
  	error = git_filebuf_commit_at(&file, file.path_lock, GIT_PACK_FILE_MODE);
  cleanup:
  	if (error < GIT_SUCCESS)
  		git_filebuf_cleanup(&file);
      git_buf_free(&path);
  
  	return error;
  }
  

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