Revision b81401c1de0e0fec39f8643ce7a794fda083f7a1 authored by Jeff King on 27 August 2012, 13:27:15 UTC, committed by Junio C Hamano on 27 August 2012, 17:49:09 UTC
All of the smart-http GET requests go through the http_get_*
functions, which will prompt for credentials and retry if we
see an HTTP 401.

POST requests, however, do not go through any central point.
Moreover, it is difficult to retry in the general case; we
cannot assume the request body fits in memory or is even
seekable, and we don't know how much of it was consumed
during the attempt.

Most of the time, this is not a big deal; for both fetching
and pushing, we make a GET request before doing any POSTs,
so typically we figure out the credentials during the first
request, then reuse them during the POST. However, some
servers may allow a client to get the list of refs from
receive-pack without authentication, and then require
authentication when the client actually tries to POST the
pack.

This is not ideal, as the client may do a non-trivial amount
of work to generate the pack (e.g., delta-compressing
objects). However, for a long time it has been the
recommended example configuration in git-http-backend(1) for
setting up a repository with anonymous fetch and
authenticated push. This setup has always been broken
without putting a username into the URL. Prior to commit
986bbc0, it did work with a username in the URL, because git
would prompt for credentials before making any requests at
all. However, post-986bbc0, it is totally broken. Since it
has been advertised in the manpage for some time, we should
make sure it works.

Unfortunately, it is not as easy as simply calling post_rpc
again when it fails, due to the input issue mentioned above.
However, we can still make this specific case work by
retrying in two specific instances:

  1. If the request is large (bigger than LARGE_PACKET_MAX),
     we will first send a probe request with a single flush
     packet. Since this request is static, we can freely
     retry it.

  2. If the request is small and we are not using gzip, then
     we have the whole thing in-core, and we can freely
     retry.

That means we will not retry in some instances, including:

  1. If we are using gzip. However, we only do so when
     calling git-upload-pack, so it does not apply to
     pushes.

  2. If we have a large request, the probe succeeds, but
     then the real POST wants authentication. This is an
     extremely unlikely configuration and not worth worrying
     about.

While it might be nice to cover those instances, doing so
would be significantly more complex for very little
real-world gain. In the long run, we will be much better off
when curl learns to internally handle authentication as a
callback, and we can cleanly handle all cases that way.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 8809703
Raw File
reflog-walk.c
#include "cache.h"
#include "commit.h"
#include "refs.h"
#include "diff.h"
#include "revision.h"
#include "string-list.h"
#include "reflog-walk.h"

struct complete_reflogs {
	char *ref;
	const char *short_ref;
	struct reflog_info {
		unsigned char osha1[20], nsha1[20];
		char *email;
		unsigned long timestamp;
		int tz;
		char *message;
	} *items;
	int nr, alloc;
};

static int read_one_reflog(unsigned char *osha1, unsigned char *nsha1,
		const char *email, unsigned long timestamp, int tz,
		const char *message, void *cb_data)
{
	struct complete_reflogs *array = cb_data;
	struct reflog_info *item;

	if (array->nr >= array->alloc) {
		array->alloc = alloc_nr(array->nr + 1);
		array->items = xrealloc(array->items, array->alloc *
			sizeof(struct reflog_info));
	}
	item = array->items + array->nr;
	memcpy(item->osha1, osha1, 20);
	memcpy(item->nsha1, nsha1, 20);
	item->email = xstrdup(email);
	item->timestamp = timestamp;
	item->tz = tz;
	item->message = xstrdup(message);
	array->nr++;
	return 0;
}

static struct complete_reflogs *read_complete_reflog(const char *ref)
{
	struct complete_reflogs *reflogs =
		xcalloc(sizeof(struct complete_reflogs), 1);
	reflogs->ref = xstrdup(ref);
	for_each_reflog_ent(ref, read_one_reflog, reflogs);
	if (reflogs->nr == 0) {
		unsigned char sha1[20];
		const char *name;
		void *name_to_free;
		name = name_to_free = resolve_refdup(ref, sha1, 1, NULL);
		if (name) {
			for_each_reflog_ent(name, read_one_reflog, reflogs);
			free(name_to_free);
		}
	}
	if (reflogs->nr == 0) {
		int len = strlen(ref);
		char *refname = xmalloc(len + 12);
		sprintf(refname, "refs/%s", ref);
		for_each_reflog_ent(refname, read_one_reflog, reflogs);
		if (reflogs->nr == 0) {
			sprintf(refname, "refs/heads/%s", ref);
			for_each_reflog_ent(refname, read_one_reflog, reflogs);
		}
		free(refname);
	}
	return reflogs;
}

static int get_reflog_recno_by_time(struct complete_reflogs *array,
	unsigned long timestamp)
{
	int i;
	for (i = array->nr - 1; i >= 0; i--)
		if (timestamp >= array->items[i].timestamp)
			return i;
	return -1;
}

struct commit_info_lifo {
	struct commit_info {
		struct commit *commit;
		void *util;
	} *items;
	int nr, alloc;
};

static struct commit_info *get_commit_info(struct commit *commit,
		struct commit_info_lifo *lifo, int pop)
{
	int i;
	for (i = 0; i < lifo->nr; i++)
		if (lifo->items[i].commit == commit) {
			struct commit_info *result = &lifo->items[i];
			if (pop) {
				if (i + 1 < lifo->nr)
					memmove(lifo->items + i,
						lifo->items + i + 1,
						(lifo->nr - i) *
						sizeof(struct commit_info));
				lifo->nr--;
			}
			return result;
		}
	return NULL;
}

static void add_commit_info(struct commit *commit, void *util,
		struct commit_info_lifo *lifo)
{
	struct commit_info *info;
	if (lifo->nr >= lifo->alloc) {
		lifo->alloc = alloc_nr(lifo->nr + 1);
		lifo->items = xrealloc(lifo->items,
			lifo->alloc * sizeof(struct commit_info));
	}
	info = lifo->items + lifo->nr;
	info->commit = commit;
	info->util = util;
	lifo->nr++;
}

struct commit_reflog {
	int recno;
	enum selector_type {
		SELECTOR_NONE,
		SELECTOR_INDEX,
		SELECTOR_DATE
	} selector;
	struct complete_reflogs *reflogs;
};

struct reflog_walk_info {
	struct commit_info_lifo reflogs;
	struct string_list complete_reflogs;
	struct commit_reflog *last_commit_reflog;
};

void init_reflog_walk(struct reflog_walk_info** info)
{
	*info = xcalloc(sizeof(struct reflog_walk_info), 1);
}

int add_reflog_for_walk(struct reflog_walk_info *info,
		struct commit *commit, const char *name)
{
	unsigned long timestamp = 0;
	int recno = -1;
	struct string_list_item *item;
	struct complete_reflogs *reflogs;
	char *branch, *at = strchr(name, '@');
	struct commit_reflog *commit_reflog;
	enum selector_type selector = SELECTOR_NONE;

	if (commit->object.flags & UNINTERESTING)
		die ("Cannot walk reflogs for %s", name);

	branch = xstrdup(name);
	if (at && at[1] == '{') {
		char *ep;
		branch[at - name] = '\0';
		recno = strtoul(at + 2, &ep, 10);
		if (*ep != '}') {
			recno = -1;
			timestamp = approxidate(at + 2);
			selector = SELECTOR_DATE;
		}
		else
			selector = SELECTOR_INDEX;
	} else
		recno = 0;

	item = string_list_lookup(&info->complete_reflogs, branch);
	if (item)
		reflogs = item->util;
	else {
		if (*branch == '\0') {
			unsigned char sha1[20];
			free(branch);
			branch = resolve_refdup("HEAD", sha1, 0, NULL);
			if (!branch)
				die ("No current branch");

		}
		reflogs = read_complete_reflog(branch);
		if (!reflogs || reflogs->nr == 0) {
			unsigned char sha1[20];
			char *b;
			if (dwim_log(branch, strlen(branch), sha1, &b) == 1) {
				if (reflogs) {
					free(reflogs->ref);
					free(reflogs);
				}
				free(branch);
				branch = b;
				reflogs = read_complete_reflog(branch);
			}
		}
		if (!reflogs || reflogs->nr == 0)
			return -1;
		string_list_insert(&info->complete_reflogs, branch)->util
			= reflogs;
	}

	commit_reflog = xcalloc(sizeof(struct commit_reflog), 1);
	if (recno < 0) {
		commit_reflog->recno = get_reflog_recno_by_time(reflogs, timestamp);
		if (commit_reflog->recno < 0) {
			free(branch);
			free(commit_reflog);
			return -1;
		}
	} else
		commit_reflog->recno = reflogs->nr - recno - 1;
	commit_reflog->selector = selector;
	commit_reflog->reflogs = reflogs;

	add_commit_info(commit, commit_reflog, &info->reflogs);
	return 0;
}

void fake_reflog_parent(struct reflog_walk_info *info, struct commit *commit)
{
	struct commit_info *commit_info =
		get_commit_info(commit, &info->reflogs, 0);
	struct commit_reflog *commit_reflog;
	struct reflog_info *reflog;

	info->last_commit_reflog = NULL;
	if (!commit_info)
		return;

	commit_reflog = commit_info->util;
	if (commit_reflog->recno < 0) {
		commit->parents = NULL;
		return;
	}

	reflog = &commit_reflog->reflogs->items[commit_reflog->recno];
	info->last_commit_reflog = commit_reflog;
	commit_reflog->recno--;
	commit_info->commit = (struct commit *)parse_object(reflog->osha1);
	if (!commit_info->commit) {
		commit->parents = NULL;
		return;
	}

	commit->parents = xcalloc(sizeof(struct commit_list), 1);
	commit->parents->item = commit_info->commit;
}

void get_reflog_selector(struct strbuf *sb,
			 struct reflog_walk_info *reflog_info,
			 enum date_mode dmode, int force_date,
			 int shorten)
{
	struct commit_reflog *commit_reflog = reflog_info->last_commit_reflog;
	struct reflog_info *info;
	const char *printed_ref;

	if (!commit_reflog)
		return;

	if (shorten) {
		if (!commit_reflog->reflogs->short_ref)
			commit_reflog->reflogs->short_ref
				= shorten_unambiguous_ref(commit_reflog->reflogs->ref, 0);
		printed_ref = commit_reflog->reflogs->short_ref;
	} else {
		printed_ref = commit_reflog->reflogs->ref;
	}

	strbuf_addf(sb, "%s@{", printed_ref);
	if (commit_reflog->selector == SELECTOR_DATE ||
	    (commit_reflog->selector == SELECTOR_NONE && force_date)) {
		info = &commit_reflog->reflogs->items[commit_reflog->recno+1];
		strbuf_addstr(sb, show_date(info->timestamp, info->tz, dmode));
	} else {
		strbuf_addf(sb, "%d", commit_reflog->reflogs->nr
			    - 2 - commit_reflog->recno);
	}

	strbuf_addch(sb, '}');
}

void get_reflog_message(struct strbuf *sb,
			struct reflog_walk_info *reflog_info)
{
	struct commit_reflog *commit_reflog = reflog_info->last_commit_reflog;
	struct reflog_info *info;
	size_t len;

	if (!commit_reflog)
		return;

	info = &commit_reflog->reflogs->items[commit_reflog->recno+1];
	len = strlen(info->message);
	if (len > 0)
		len--; /* strip away trailing newline */
	strbuf_add(sb, info->message, len);
}

const char *get_reflog_ident(struct reflog_walk_info *reflog_info)
{
	struct commit_reflog *commit_reflog = reflog_info->last_commit_reflog;
	struct reflog_info *info;

	if (!commit_reflog)
		return NULL;

	info = &commit_reflog->reflogs->items[commit_reflog->recno+1];
	return info->email;
}

void show_reflog_message(struct reflog_walk_info *reflog_info, int oneline,
			 enum date_mode dmode, int force_date)
{
	if (reflog_info && reflog_info->last_commit_reflog) {
		struct commit_reflog *commit_reflog = reflog_info->last_commit_reflog;
		struct reflog_info *info;
		struct strbuf selector = STRBUF_INIT;

		info = &commit_reflog->reflogs->items[commit_reflog->recno+1];
		get_reflog_selector(&selector, reflog_info, dmode, force_date, 0);
		if (oneline) {
			printf("%s: %s", selector.buf, info->message);
		}
		else {
			printf("Reflog: %s (%s)\nReflog message: %s",
			       selector.buf, info->email, info->message);
		}

		strbuf_release(&selector);
	}
}
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