thodg/libgit2/examples/fetch.c

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• Hash : ead10785
  Author :
  Date : 2019-01-24T11:31:49
  

  examples: create common lg2 executable Inside of our networking example code, we have a git2 executable that acts as an entry point to all the different network examples. As such, it is kind of the same like the normal git(1) executable in that it simply arbitrates to the respective subcommands. Let's extend this approach and merge all examples into a single standalone lg2 executable. Instead of building an executable for all the existing examples we have, we now bundle them all inside of the lg2 one and let them be callable via subcommands. In the process, we can get rid of duplicated library initialization, deinitialization and repository discovery code. Instead of having each subcommand handle these on its own, we simply do it inside of the single main function now.

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• examples/fetch.c

• #include "common.h"
  
  static int progress_cb(const char *str, int len, void *data)
  {
  	(void)data;
  	printf("remote: %.*s", len, str);
  	fflush(stdout); /* We don't have the \n to force the flush */
  	return 0;
  }
  
  /**
   * This function gets called for each remote-tracking branch that gets
   * updated. The message we output depends on whether it's a new one or
   * an update.
   */
  static int update_cb(const char *refname, const git_oid *a, const git_oid *b, void *data)
  {
  	char a_str[GIT_OID_HEXSZ+1], b_str[GIT_OID_HEXSZ+1];
  	(void)data;
  
  	git_oid_fmt(b_str, b);
  	b_str[GIT_OID_HEXSZ] = '\0';
  
  	if (git_oid_iszero(a)) {
  		printf("[new]     %.20s %s\n", b_str, refname);
  	} else {
  		git_oid_fmt(a_str, a);
  		a_str[GIT_OID_HEXSZ] = '\0';
  		printf("[updated] %.10s..%.10s %s\n", a_str, b_str, refname);
  	}
  
  	return 0;
  }
  
  /**
   * This gets called during the download and indexing. Here we show
   * processed and total objects in the pack and the amount of received
   * data. Most frontends will probably want to show a percentage and
   * the download rate.
   */
  static int transfer_progress_cb(const git_transfer_progress *stats, void *payload)
  {
  	(void)payload;
  
  	if (stats->received_objects == stats->total_objects) {
  		printf("Resolving deltas %d/%d\r",
  		       stats->indexed_deltas, stats->total_deltas);
  	} else if (stats->total_objects > 0) {
  		printf("Received %d/%d objects (%d) in %" PRIuZ " bytes\r",
  		       stats->received_objects, stats->total_objects,
  		       stats->indexed_objects, stats->received_bytes);
  	}
  	return 0;
  }
  
  /** Entry point for this command */
  int lg2_fetch(git_repository *repo, int argc, char **argv)
  {
  	git_remote *remote = NULL;
  	const git_transfer_progress *stats;
  	git_fetch_options fetch_opts = GIT_FETCH_OPTIONS_INIT;
  
  	if (argc < 2) {
  		fprintf(stderr, "usage: %s fetch <repo>\n", argv[-1]);
  		return EXIT_FAILURE;
  	}
  
  	/* Figure out whether it's a named remote or a URL */
  	printf("Fetching %s for repo %p\n", argv[1], repo);
  	if (git_remote_lookup(&remote, repo, argv[1]) < 0)
  		if (git_remote_create_anonymous(&remote, repo, argv[1]) < 0)
  			goto on_error;
  
  	/* Set up the callbacks (only update_tips for now) */
  	fetch_opts.callbacks.update_tips = &update_cb;
  	fetch_opts.callbacks.sideband_progress = &progress_cb;
  	fetch_opts.callbacks.transfer_progress = transfer_progress_cb;
  	fetch_opts.callbacks.credentials = cred_acquire_cb;
  
  	/**
  	 * Perform the fetch with the configured refspecs from the
  	 * config. Update the reflog for the updated references with
  	 * "fetch".
  	 */
  	if (git_remote_fetch(remote, NULL, &fetch_opts, "fetch") < 0)
  		goto on_error;
  
  	/**
  	 * If there are local objects (we got a thin pack), then tell
  	 * the user how many objects we saved from having to cross the
  	 * network.
  	 */
  	stats = git_remote_stats(remote);
  	if (stats->local_objects > 0) {
  		printf("\rReceived %d/%d objects in %" PRIuZ " bytes (used %d local objects)\n",
  		       stats->indexed_objects, stats->total_objects, stats->received_bytes, stats->local_objects);
  	} else{
  		printf("\rReceived %d/%d objects in %" PRIuZ "bytes\n",
  			stats->indexed_objects, stats->total_objects, stats->received_bytes);
  	}
  
  	git_remote_free(remote);
  
  	return 0;
  
   on_error:
  	git_remote_free(remote);
  	return -1;
  }
  

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