thodg/libgit2/src/transports/smart_protocol.c

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• Hash : 2f8c481c
  Author :
  Date : 2013-10-08T16:22:21
  

  protocol: basic support for multi_ack_detailed This tells the server that we speak it, but we don't make use of its extra information to determine if there's a better place to stop negotiating. In a somewhat-related change, reorder the capabilities so we ask for them in the same order as git does. Also take this opportunity to factor out a fairly-indented portion of the negotiation logic.

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• src/transports/smart_protocol.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.h"
  #include "git2/odb_backend.h"
  
  #include "smart.h"
  #include "refs.h"
  #include "repository.h"
  #include "push.h"
  #include "pack-objects.h"
  #include "remote.h"
  #include "util.h"
  
  #define NETWORK_XFER_THRESHOLD (100*1024)
  /* The minimal interval between progress updates (in seconds). */
  #define MIN_PROGRESS_UPDATE_INTERVAL 0.5
  
  int git_smart__store_refs(transport_smart *t, int flushes)
  {
  	gitno_buffer *buf = &t->buffer;
  	git_vector *refs = &t->refs;
  	int error, flush = 0, recvd;
  	const char *line_end = NULL;
  	git_pkt *pkt = NULL;
  	git_pkt_ref *ref;
  	size_t i;
  
  	/* Clear existing refs in case git_remote_connect() is called again
  	 * after git_remote_disconnect().
  	 */
  	git_vector_foreach(refs, i, ref) {
  		git__free(ref->head.name);
  		git__free(ref);
  	}
  	git_vector_clear(refs);
  
  	do {
  		if (buf->offset > 0)
  			error = git_pkt_parse_line(&pkt, buf->data, &line_end, buf->offset);
  		else
  			error = GIT_EBUFS;
  
  		if (error < 0 && error != GIT_EBUFS)
  			return -1;
  
  		if (error == GIT_EBUFS) {
  			if ((recvd = gitno_recv(buf)) < 0)
  				return -1;
  
  			if (recvd == 0 && !flush) {
  				giterr_set(GITERR_NET, "Early EOF");
  				return -1;
  			}
  
  			continue;
  		}
  
  		gitno_consume(buf, line_end);
  		if (pkt->type == GIT_PKT_ERR) {
  			giterr_set(GITERR_NET, "Remote error: %s", ((git_pkt_err *)pkt)->error);
  			git__free(pkt);
  			return -1;
  		}
  
  		if (pkt->type != GIT_PKT_FLUSH && git_vector_insert(refs, pkt) < 0)
  			return -1;
  
  		if (pkt->type == GIT_PKT_FLUSH) {
  			flush++;
  			git_pkt_free(pkt);
  		}
  	} while (flush < flushes);
  
  	return flush;
  }
  
  int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps)
  {
  	const char *ptr;
  
  	/* No refs or capabilites, odd but not a problem */
  	if (pkt == NULL || pkt->capabilities == NULL)
  		return 0;
  
  	ptr = pkt->capabilities;
  	while (ptr != NULL && *ptr != '\0') {
  		if (*ptr == ' ')
  			ptr++;
  
  		if (!git__prefixcmp(ptr, GIT_CAP_OFS_DELTA)) {
  			caps->common = caps->ofs_delta = 1;
  			ptr += strlen(GIT_CAP_OFS_DELTA);
  			continue;
  		}
  
  		/* Keep multi_ack_detailed before multi_ack */
  		if (!git__prefixcmp(ptr, GIT_CAP_MULTI_ACK_DETAILED)) {
  			caps->common = caps->multi_ack_detailed = 1;
  			ptr += strlen(GIT_CAP_MULTI_ACK_DETAILED);
  			continue;
  		}
  
  		if (!git__prefixcmp(ptr, GIT_CAP_MULTI_ACK)) {
  			caps->common = caps->multi_ack = 1;
  			ptr += strlen(GIT_CAP_MULTI_ACK);
  			continue;
  		}
  
  		if (!git__prefixcmp(ptr, GIT_CAP_INCLUDE_TAG)) {
  			caps->common = caps->include_tag = 1;
  			ptr += strlen(GIT_CAP_INCLUDE_TAG);
  			continue;
  		}
  
  		/* Keep side-band check after side-band-64k */
  		if (!git__prefixcmp(ptr, GIT_CAP_SIDE_BAND_64K)) {
  			caps->common = caps->side_band_64k = 1;
  			ptr += strlen(GIT_CAP_SIDE_BAND_64K);
  			continue;
  		}
  
  		if (!git__prefixcmp(ptr, GIT_CAP_SIDE_BAND)) {
  			caps->common = caps->side_band = 1;
  			ptr += strlen(GIT_CAP_SIDE_BAND);
  			continue;
  		}
  
  		if (!git__prefixcmp(ptr, GIT_CAP_DELETE_REFS)) {
  			caps->common = caps->delete_refs = 1;
  			ptr += strlen(GIT_CAP_DELETE_REFS);
  			continue;
  		}
  
  		if (!git__prefixcmp(ptr, GIT_CAP_THIN_PACK)) {
  			caps->common = caps->thin_pack = 1;
  			ptr += strlen(GIT_CAP_THIN_PACK);
  			continue;
  		}
  
  		/* We don't know this capability, so skip it */
  		ptr = strchr(ptr, ' ');
  	}
  
  	return 0;
  }
  
  static int recv_pkt(git_pkt **out, gitno_buffer *buf)
  {
  	const char *ptr = buf->data, *line_end = ptr;
  	git_pkt *pkt = NULL;
  	int pkt_type, error = 0, ret;
  
  	do {
  		if (buf->offset > 0)
  			error = git_pkt_parse_line(&pkt, ptr, &line_end, buf->offset);
  		else
  			error = GIT_EBUFS;
  
  		if (error == 0)
  			break; /* return the pkt */
  
  		if (error < 0 && error != GIT_EBUFS)
  			return -1;
  
  		if ((ret = gitno_recv(buf)) < 0)
  			return -1;
  	} while (error);
  
  	gitno_consume(buf, line_end);
  	pkt_type = pkt->type;
  	if (out != NULL)
  		*out = pkt;
  	else
  		git__free(pkt);
  
  	return pkt_type;
  }
  
  static int store_common(transport_smart *t)
  {
  	git_pkt *pkt = NULL;
  	gitno_buffer *buf = &t->buffer;
  
  	do {
  		if (recv_pkt(&pkt, buf) < 0)
  			return -1;
  
  		if (pkt->type == GIT_PKT_ACK) {
  			if (git_vector_insert(&t->common, pkt) < 0)
  				return -1;
  		} else {
  			git__free(pkt);
  			return 0;
  		}
  
  	} while (1);
  
  	return 0;
  }
  
  static int fetch_setup_walk(git_revwalk **out, git_repository *repo)
  {
  	git_revwalk *walk;
  	git_strarray refs;
  	unsigned int i;
  	git_reference *ref;
  
  	if (git_reference_list(&refs, repo) < 0)
  		return -1;
  
  	if (git_revwalk_new(&walk, repo) < 0)
  		return -1;
  
  	git_revwalk_sorting(walk, GIT_SORT_TIME);
  
  	for (i = 0; i < refs.count; ++i) {
  		/* No tags */
  		if (!git__prefixcmp(refs.strings[i], GIT_REFS_TAGS_DIR))
  			continue;
  
  		if (git_reference_lookup(&ref, repo, refs.strings[i]) < 0)
  			goto on_error;
  
  		if (git_reference_type(ref) == GIT_REF_SYMBOLIC)
  			continue;
  		if (git_revwalk_push(walk, git_reference_target(ref)) < 0)
  			goto on_error;
  
  		git_reference_free(ref);
  	}
  
  	git_strarray_free(&refs);
  	*out = walk;
  	return 0;
  
  on_error:
  	git_reference_free(ref);
  	git_strarray_free(&refs);
  	return -1;
  }
  
  static int wait_while_ack(gitno_buffer *buf)
  {
  	int error;
  	git_pkt_ack *pkt = NULL;
  
  	while (1) {
  		git__free(pkt);
  
  		if ((error = recv_pkt((git_pkt **)&pkt, buf)) < 0)
  			return error;
  
  		if (pkt->type == GIT_PKT_NAK)
  			break;
  
  		if (pkt->type == GIT_PKT_ACK &&
  		    (pkt->status != GIT_ACK_CONTINUE ||
  		     pkt->status != GIT_ACK_COMMON)) {
  			git__free(pkt);
  			break;
  		}
  	}
  
  	git__free(pkt);
  	return 0;
  }
  
  int git_smart__negotiate_fetch(git_transport *transport, git_repository *repo, const git_remote_head * const *refs, size_t count)
  {
  	transport_smart *t = (transport_smart *)transport;
  	gitno_buffer *buf = &t->buffer;
  	git_buf data = GIT_BUF_INIT;
  	git_revwalk *walk = NULL;
  	int error = -1, pkt_type;
  	unsigned int i;
  	git_oid oid;
  
  	/* No own logic, do our thing */
  	if ((error = git_pkt_buffer_wants(refs, count, &t->caps, &data)) < 0)
  		return error;
  
  	if ((error = fetch_setup_walk(&walk, repo)) < 0)
  		goto on_error;
  	/*
  	 * We don't support any kind of ACK extensions, so the negotiation
  	 * boils down to sending what we have and listening for an ACK
  	 * every once in a while.
  	 */
  	i = 0;
  	while (true) {
  		error = git_revwalk_next(&oid, walk);
  
  		if (error < 0) {
  			if (GIT_ITEROVER == error)
  				break;
  
  			goto on_error;
  		}
  
  		git_pkt_buffer_have(&oid, &data);
  		i++;
  		if (i % 20 == 0) {
  			if (t->cancelled.val) {
  				giterr_set(GITERR_NET, "The fetch was cancelled by the user");
  				error = GIT_EUSER;
  				goto on_error;
  			}
  
  			git_pkt_buffer_flush(&data);
  			if (git_buf_oom(&data)) {
  				error = -1;
  				goto on_error;
  			}
  
  			if ((error = git_smart__negotiation_step(&t->parent, data.ptr, data.size)) < 0)
  				goto on_error;
  
  			git_buf_clear(&data);
  			if (t->caps.multi_ack || t->caps.multi_ack_detailed) {
  				if ((error = store_common(t)) < 0)
  					goto on_error;
  			} else {
  				pkt_type = recv_pkt(NULL, buf);
  
  				if (pkt_type == GIT_PKT_ACK) {
  					break;
  				} else if (pkt_type == GIT_PKT_NAK) {
  					continue;
  				} else if (pkt_type < 0) {
  					/* recv_pkt returned an error */
  					error = pkt_type;
  					goto on_error;
  				} else {
  					giterr_set(GITERR_NET, "Unexpected pkt type");
  					error = -1;
  					goto on_error;
  				}
  			}
  		}
  
  		if (t->common.length > 0)
  			break;
  
  		if (i % 20 == 0 && t->rpc) {
  			git_pkt_ack *pkt;
  			unsigned int i;
  
  			if ((error = git_pkt_buffer_wants(refs, count, &t->caps, &data)) < 0)
  				goto on_error;
  
  			git_vector_foreach(&t->common, i, pkt) {
  				if ((error = git_pkt_buffer_have(&pkt->oid, &data)) < 0)
  					goto on_error;
  			}
  
  			if (git_buf_oom(&data)) {
  				error = -1;
  				goto on_error;
  			}
  		}
  	}
  
  	/* Tell the other end that we're done negotiating */
  	if (t->rpc && t->common.length > 0) {
  		git_pkt_ack *pkt;
  		unsigned int i;
  
  		if ((error = git_pkt_buffer_wants(refs, count, &t->caps, &data)) < 0)
  			goto on_error;
  
  		git_vector_foreach(&t->common, i, pkt) {
  			if ((error = git_pkt_buffer_have(&pkt->oid, &data)) < 0)
  				goto on_error;
  		}
  
  		if (git_buf_oom(&data)) {
  			error = -1;
  			goto on_error;
  		}
  	}
  
  	if ((error = git_pkt_buffer_done(&data)) < 0)
  		goto on_error;
  
  	if (t->cancelled.val) {
  		giterr_set(GITERR_NET, "The fetch was cancelled by the user");
  		error = GIT_EUSER;
  		goto on_error;
  	}
  	if ((error = git_smart__negotiation_step(&t->parent, data.ptr, data.size)) < 0)
  		goto on_error;
  
  	git_buf_free(&data);
  	git_revwalk_free(walk);
  
  	/* Now let's eat up whatever the server gives us */
  	if (!t->caps.multi_ack && !t->caps.multi_ack_detailed) {
  		pkt_type = recv_pkt(NULL, buf);
  
  		if (pkt_type < 0) {
  			return pkt_type;
  		} else if (pkt_type != GIT_PKT_ACK && pkt_type != GIT_PKT_NAK) {
  			giterr_set(GITERR_NET, "Unexpected pkt type");
  			return -1;
  		}
  	} else {
  		error = wait_while_ack(buf);
  	}
  
  	return error;
  
  on_error:
  	git_revwalk_free(walk);
  	git_buf_free(&data);
  	return error;
  }
  
  static int no_sideband(transport_smart *t, struct git_odb_writepack *writepack, gitno_buffer *buf, git_transfer_progress *stats)
  {
  	int recvd;
  
  	do {
  		if (t->cancelled.val) {
  			giterr_set(GITERR_NET, "The fetch was cancelled by the user");
  			return GIT_EUSER;
  		}
  
  		if (writepack->add(writepack, buf->data, buf->offset, stats) < 0)
  			return -1;
  
  		gitno_consume_n(buf, buf->offset);
  
  		if ((recvd = gitno_recv(buf)) < 0)
  			return -1;
  	} while(recvd > 0);
  
  	if (writepack->commit(writepack, stats))
  		return -1;
  
  	return 0;
  }
  
  struct network_packetsize_payload
  {
  	git_transfer_progress_callback callback;
  	void *payload;
  	git_transfer_progress *stats;
  	size_t last_fired_bytes;
  };
  
  static int network_packetsize(size_t received, void *payload)
  {
  	struct network_packetsize_payload *npp = (struct network_packetsize_payload*)payload;
  
  	/* Accumulate bytes */
  	npp->stats->received_bytes += received;
  
  	/* Fire notification if the threshold is reached */
  	if ((npp->stats->received_bytes - npp->last_fired_bytes) > NETWORK_XFER_THRESHOLD) {
  		npp->last_fired_bytes = npp->stats->received_bytes;
  
  		if (npp->callback(npp->stats, npp->payload))
  			return GIT_EUSER;
  	}
  
  	return 0;
  }
  
  int git_smart__download_pack(
  	git_transport *transport,
  	git_repository *repo,
  	git_transfer_progress *stats,
  	git_transfer_progress_callback progress_cb,
  	void *progress_payload)
  {
  	transport_smart *t = (transport_smart *)transport;
  	gitno_buffer *buf = &t->buffer;
  	git_odb *odb;
  	struct git_odb_writepack *writepack = NULL;
  	int error = 0;
  	struct network_packetsize_payload npp = {0};
  
  	memset(stats, 0, sizeof(git_transfer_progress));
  
  	if (progress_cb) {
  		npp.callback = progress_cb;
  		npp.payload = progress_payload;
  		npp.stats = stats;
  		t->packetsize_cb = &network_packetsize;
  		t->packetsize_payload = &npp;
  
  		/* We might have something in the buffer already from negotiate_fetch */
  		if (t->buffer.offset > 0 && !t->cancelled.val)
  			if (t->packetsize_cb(t->buffer.offset, t->packetsize_payload))
  				git_atomic_set(&t->cancelled, 1);
  	}
  
  	if ((error = git_repository_odb__weakptr(&odb, repo)) < 0 ||
  		((error = git_odb_write_pack(&writepack, odb, progress_cb, progress_payload)) < 0))
  		goto done;
  
  	/*
  	 * If the remote doesn't support the side-band, we can feed
  	 * the data directly to the pack writer. Otherwise, we need to
  	 * check which one belongs there.
  	 */
  	if (!t->caps.side_band && !t->caps.side_band_64k) {
  		error = no_sideband(t, writepack, buf, stats);
  		goto done;
  	}
  
  	do {
  		git_pkt *pkt;
  
  		/* Check cancellation before network call */
  		if (t->cancelled.val) {
  			giterr_set(GITERR_NET, "The fetch was cancelled by the user");
  			error = GIT_EUSER;
  			goto done;
  		}
  
  		if ((error = recv_pkt(&pkt, buf)) < 0)
  			goto done;
  
  		/* Check cancellation after network call */
  		if (t->cancelled.val) {
  			giterr_set(GITERR_NET, "The fetch was cancelled by the user");
  			error = GIT_EUSER;
  			goto done;
  		}
  
  		if (pkt->type == GIT_PKT_PROGRESS) {
  			if (t->progress_cb) {
  				git_pkt_progress *p = (git_pkt_progress *) pkt;
  				if (t->progress_cb(p->data, p->len, t->message_cb_payload)) {
  					giterr_set(GITERR_NET, "The fetch was cancelled by the user");
  					return GIT_EUSER;
  				}
  			}
  			git__free(pkt);
  		} else if (pkt->type == GIT_PKT_DATA) {
  			git_pkt_data *p = (git_pkt_data *) pkt;
  			error = writepack->add(writepack, p->data, p->len, stats);
  
  			git__free(pkt);
  			if (error < 0)
  				goto done;
  		} else if (pkt->type == GIT_PKT_FLUSH) {
  			/* A flush indicates the end of the packfile */
  			git__free(pkt);
  			break;
  		}
  	} while (1);
  
  	error = writepack->commit(writepack, stats);
  
  done:
  	if (writepack)
  		writepack->free(writepack);
  
  	/* Trailing execution of progress_cb, if necessary */
  	if (npp.callback && npp.stats->received_bytes > npp.last_fired_bytes)
  		npp.callback(npp.stats, npp.payload);
  
  	return error;
  }
  
  static int gen_pktline(git_buf *buf, git_push *push)
  {
  	push_spec *spec;
  	size_t i, len;
  	char old_id[41], new_id[41];
  
  	old_id[40] = '\0'; new_id[40] = '\0';
  
  	git_vector_foreach(&push->specs, i, spec) {
  		len = 2*GIT_OID_HEXSZ + 7 + strlen(spec->rref);
  
  		if (i == 0) {
  			++len; /* '\0' */
  			if (push->report_status)
  				len += strlen(GIT_CAP_REPORT_STATUS) + 1;
  			len += strlen(GIT_CAP_SIDE_BAND_64K) + 1;
  		}
  
  		git_oid_fmt(old_id, &spec->roid);
  		git_oid_fmt(new_id, &spec->loid);
  
  		git_buf_printf(buf, "%04"PRIxZ"%s %s %s", len, old_id, new_id, spec->rref);
  
  		if (i == 0) {
  			git_buf_putc(buf, '\0');
  			/* Core git always starts their capabilities string with a space */
  			if (push->report_status) {
  				git_buf_putc(buf, ' ');
  				git_buf_printf(buf, GIT_CAP_REPORT_STATUS);
  			}
  			git_buf_putc(buf, ' ');
  			git_buf_printf(buf, GIT_CAP_SIDE_BAND_64K);
  		}
  
  		git_buf_putc(buf, '\n');
  	}
  
  	git_buf_puts(buf, "0000");
  	return git_buf_oom(buf) ? -1 : 0;
  }
  
  static int add_push_report_pkt(git_push *push, git_pkt *pkt)
  {
  	push_status *status;
  
  	switch (pkt->type) {
  		case GIT_PKT_OK:
  			status = git__calloc(1, sizeof(push_status));
  			GITERR_CHECK_ALLOC(status);
  			status->msg = NULL;
  			status->ref = git__strdup(((git_pkt_ok *)pkt)->ref);
  			if (!status->ref ||
  				git_vector_insert(&push->status, status) < 0) {
  				git_push_status_free(status);
  				return -1;
  			}
  			break;
  		case GIT_PKT_NG:
  			status = git__calloc(sizeof(push_status), 1);
  			GITERR_CHECK_ALLOC(status);
  			status->ref = git__strdup(((git_pkt_ng *)pkt)->ref);
  			status->msg = git__strdup(((git_pkt_ng *)pkt)->msg);
  			if (!status->ref || !status->msg ||
  				git_vector_insert(&push->status, status) < 0) {
  				git_push_status_free(status);
  				return -1;
  			}
  			break;
  		case GIT_PKT_UNPACK:
  			push->unpack_ok = ((git_pkt_unpack *)pkt)->unpack_ok;
  			break;
  		case GIT_PKT_FLUSH:
  			return GIT_ITEROVER;
  		default:
  			giterr_set(GITERR_NET, "report-status: protocol error");
  			return -1;
  	}
  
  	return 0;
  }
  
  static int add_push_report_sideband_pkt(git_push *push, git_pkt_data *data_pkt)
  {
  	git_pkt *pkt;
  	const char *line = data_pkt->data, *line_end;
  	size_t line_len = data_pkt->len;
  	int error;
  
  	while (line_len > 0) {
  		error = git_pkt_parse_line(&pkt, line, &line_end, line_len);
  
  		if (error < 0)
  			return error;
  
  		/* Advance in the buffer */
  		line_len -= (line_end - line);
  		line = line_end;
  
  		error = add_push_report_pkt(push, pkt);
  
  		git_pkt_free(pkt);
  
  		if (error < 0 && error != GIT_ITEROVER)
  			return error;
  	}
  
  	return 0;
  }
  
  static int parse_report(gitno_buffer *buf, git_push *push)
  {
  	git_pkt *pkt = NULL;
  	const char *line_end = NULL;
  	int error, recvd;
  
  	for (;;) {
  		if (buf->offset > 0)
  			error = git_pkt_parse_line(&pkt, buf->data,
  						   &line_end, buf->offset);
  		else
  			error = GIT_EBUFS;
  
  		if (error < 0 && error != GIT_EBUFS)
  			return -1;
  
  		if (error == GIT_EBUFS) {
  			if ((recvd = gitno_recv(buf)) < 0)
  				return -1;
  
  			if (recvd == 0) {
  				giterr_set(GITERR_NET, "Early EOF");
  				return -1;
  			}
  			continue;
  		}
  
  		gitno_consume(buf, line_end);
  
  		error = 0;
  
  		switch (pkt->type) {
  			case GIT_PKT_DATA:
  				/* This is a sideband packet which contains other packets */
  				error = add_push_report_sideband_pkt(push, (git_pkt_data *)pkt);
  				break;
  			case GIT_PKT_ERR:
  				giterr_set(GITERR_NET, "report-status: Error reported: %s",
  					((git_pkt_err *)pkt)->error);
  				error = -1;
  				break;
  			case GIT_PKT_PROGRESS:
  				break;
  			default:
  				error = add_push_report_pkt(push, pkt);
  				break;
  		}
  
  		git_pkt_free(pkt);
  
  		/* add_push_report_pkt returns GIT_ITEROVER when it receives a flush */
  		if (error == GIT_ITEROVER)
  			return 0;
  
  		if (error < 0)
  			return error;
  	}
  }
  
  static int add_ref_from_push_spec(git_vector *refs, push_spec *push_spec)
  {
  	git_pkt_ref *added = git__calloc(1, sizeof(git_pkt_ref));
  	GITERR_CHECK_ALLOC(added);
  
  	added->type = GIT_PKT_REF;
  	git_oid_cpy(&added->head.oid, &push_spec->loid);
  	added->head.name = git__strdup(push_spec->rref);
  
  	if (!added->head.name ||
  		git_vector_insert(refs, added) < 0) {
  		git_pkt_free((git_pkt *)added);
  		return -1;
  	}
  
  	return 0;
  }
  
  static int update_refs_from_report(
  	git_vector *refs,
  	git_vector *push_specs,
  	git_vector *push_report)
  {
  	git_pkt_ref *ref;
  	push_spec *push_spec;
  	push_status *push_status;
  	size_t i, j, refs_len;
  	int cmp;
  
  	/* For each push spec we sent to the server, we should have
  	 * gotten back a status packet in the push report */
  	if (push_specs->length != push_report->length) {
  		giterr_set(GITERR_NET, "report-status: protocol error");
  		return -1;
  	}
  
  	/* We require that push_specs be sorted with push_spec_rref_cmp,
  	 * and that push_report be sorted with push_status_ref_cmp */
  	git_vector_sort(push_specs);
  	git_vector_sort(push_report);
  
  	git_vector_foreach(push_specs, i, push_spec) {
  		push_status = git_vector_get(push_report, i);
  
  		/* For each push spec we sent to the server, we should have
  		 * gotten back a status packet in the push report which matches */
  		if (strcmp(push_spec->rref, push_status->ref)) {
  			giterr_set(GITERR_NET, "report-status: protocol error");
  			return -1;
  		}
  	}
  
  	/* We require that refs be sorted with ref_name_cmp */
  	git_vector_sort(refs);
  	i = j = 0;
  	refs_len = refs->length;
  
  	/* Merge join push_specs with refs */
  	while (i < push_specs->length && j < refs_len) {
  		push_spec = git_vector_get(push_specs, i);
  		push_status = git_vector_get(push_report, i);
  		ref = git_vector_get(refs, j);
  
  		cmp = strcmp(push_spec->rref, ref->head.name);
  
  		/* Iterate appropriately */
  		if (cmp <= 0) i++;
  		if (cmp >= 0) j++;
  
  		/* Add case */
  		if (cmp < 0 &&
  			!push_status->msg &&
  			add_ref_from_push_spec(refs, push_spec) < 0)
  			return -1;
  
  		/* Update case, delete case */
  		if (cmp == 0 &&
  			!push_status->msg)
  			git_oid_cpy(&ref->head.oid, &push_spec->loid);
  	}
  
  	for (; i < push_specs->length; i++) {
  		push_spec = git_vector_get(push_specs, i);
  		push_status = git_vector_get(push_report, i);
  
  		/* Add case */
  		if (!push_status->msg &&
  			add_ref_from_push_spec(refs, push_spec) < 0)
  			return -1;
  	}
  
  	/* Remove any refs which we updated to have a zero OID. */
  	git_vector_rforeach(refs, i, ref) {
  		if (git_oid_iszero(&ref->head.oid)) {
  			git_vector_remove(refs, i);
  			git_pkt_free((git_pkt *)ref);
  		}
  	}
  
  	git_vector_sort(refs);
  
  	return 0;
  }
  
  struct push_packbuilder_payload
  {
  	git_smart_subtransport_stream *stream;
  	git_packbuilder *pb;
  	git_push_transfer_progress cb;
  	void *cb_payload;
  	size_t last_bytes;
  	double last_progress_report_time;
  };
  
  static int stream_thunk(void *buf, size_t size, void *data)
  {
  	int error = 0;
  	struct push_packbuilder_payload *payload = data;
  
  	if ((error = payload->stream->write(payload->stream, (const char *)buf, size)) < 0)
  		return error;
  
  	if (payload->cb) {
  		double current_time = git__timer();
  		payload->last_bytes += size;
  
  		if ((current_time - payload->last_progress_report_time) >= MIN_PROGRESS_UPDATE_INTERVAL) {
  			payload->last_progress_report_time = current_time;
  			if (payload->cb(payload->pb->nr_written, payload->pb->nr_objects, payload->last_bytes, payload->cb_payload)) {
  				giterr_clear();
  				error = GIT_EUSER;
  			}
  		}
  	}
  
  	return error;
  }
  
  int git_smart__push(git_transport *transport, git_push *push)
  {
  	transport_smart *t = (transport_smart *)transport;
  	struct push_packbuilder_payload packbuilder_payload = {0};
  	git_buf pktline = GIT_BUF_INIT;
  	int error = 0, need_pack = 0;
  	push_spec *spec;
  	unsigned int i;
  
  	packbuilder_payload.pb = push->pb;
  
  	if (push->transfer_progress_cb) {
  		packbuilder_payload.cb = push->transfer_progress_cb;
  		packbuilder_payload.cb_payload = push->transfer_progress_cb_payload;
  	}
  
  #ifdef PUSH_DEBUG
  {
  	git_remote_head *head;
  	char hex[41]; hex[40] = '\0';
  
  	git_vector_foreach(&push->remote->refs, i, head) {
  		git_oid_fmt(hex, &head->oid);
  		fprintf(stderr, "%s (%s)\n", hex, head->name);
  	}
  
  	git_vector_foreach(&push->specs, i, spec) {
  		git_oid_fmt(hex, &spec->roid);
  		fprintf(stderr, "%s (%s) -> ", hex, spec->lref);
  		git_oid_fmt(hex, &spec->loid);
  		fprintf(stderr, "%s (%s)\n", hex, spec->rref ?
  			spec->rref : spec->lref);
  	}
  }
  #endif
  
  	/*
  	 * Figure out if we need to send a packfile; which is in all
  	 * cases except when we only send delete commands
  	 */
  	git_vector_foreach(&push->specs, i, spec) {
  		if (spec->lref) {
  			need_pack = 1;
  			break;
  		}
  	}
  
  	if ((error = git_smart__get_push_stream(t, &packbuilder_payload.stream)) < 0 ||
  		(error = gen_pktline(&pktline, push)) < 0 ||
  		(error = packbuilder_payload.stream->write(packbuilder_payload.stream, git_buf_cstr(&pktline), git_buf_len(&pktline))) < 0)
  		goto done;
  
  	if (need_pack &&
  		(error = git_packbuilder_foreach(push->pb, &stream_thunk, &packbuilder_payload)) < 0)
  		goto done;
  
  	/* If we sent nothing or the server doesn't support report-status, then
  	 * we consider the pack to have been unpacked successfully */
  	if (!push->specs.length || !push->report_status)
  		push->unpack_ok = 1;
  	else if ((error = parse_report(&t->buffer, push)) < 0)
  		goto done;
  
  	/* If progress is being reported write the final report */
  	if (push->transfer_progress_cb) {
  		push->transfer_progress_cb(push->pb->nr_written, push->pb->nr_objects, packbuilder_payload.last_bytes, push->transfer_progress_cb_payload);
  	}
  
  	if (push->status.length)
  		error = update_refs_from_report(&t->refs, &push->specs, &push->status);
  
  done:
  	git_buf_free(&pktline);
  	return error;
  }
  

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