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[PATCH] Add support for alternates in HTTP
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This tries .../objects/info/http-alternates and then
.../objects/info/alternates, looking for a file which specifies where
else to download objects and packs from.

It currently only supports absolute paths, and doesn't support full URLs.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
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@iabervon
iabervon authored and Junio C Hamano committed Sep 17, 2005
1 parent 50d69ef commit b366156
Showing 1 changed file with 134 additions and 35 deletions.
169 changes: 134 additions & 35 deletions http-fetch.c
View file
Expand Up @@ -16,7 +16,17 @@
static CURL *curl;
static struct curl_slist *no_pragma_header;

static char *base;
static char *initial_base;

struct alt_base
{
char *base;
int got_indices;
struct packed_git *packs;
struct alt_base *next;
};

struct alt_base *alt = NULL;

static SHA_CTX c;
static z_stream stream;
Expand Down Expand Up @@ -72,11 +82,9 @@ void prefetch(unsigned char *sha1)
{
}

static int got_indices = 0;

static struct packed_git *packs = NULL;
static int got_alternates = 0;

static int fetch_index(unsigned char *sha1)
static int fetch_index(struct alt_base *repo, unsigned char *sha1)
{
char *filename;
char *url;
Expand All @@ -90,9 +98,9 @@ static int fetch_index(unsigned char *sha1)
fprintf(stderr, "Getting index for pack %s\n",
sha1_to_hex(sha1));

url = xmalloc(strlen(base) + 64);
url = xmalloc(strlen(repo->base) + 64);
sprintf(url, "%s/objects/pack/pack-%s.idx",
base, sha1_to_hex(sha1));
repo->base, sha1_to_hex(sha1));

filename = sha1_pack_index_name(sha1);
indexfile = fopen(filename, "w");
Expand All @@ -114,30 +122,100 @@ static int fetch_index(unsigned char *sha1)
return 0;
}

static int setup_index(unsigned char *sha1)
static int setup_index(struct alt_base *repo, unsigned char *sha1)
{
struct packed_git *new_pack;
if (has_pack_file(sha1))
return 0; // don't list this as something we can get

if (fetch_index(sha1))
if (fetch_index(repo, sha1))
return -1;

new_pack = parse_pack_index(sha1);
new_pack->next = packs;
packs = new_pack;
new_pack->next = repo->packs;
repo->packs = new_pack;
return 0;
}

static int fetch_indices(void)
static int fetch_alternates(char *base)
{
int ret = 0;
struct buffer buffer;
char *url;
char *data;
int i = 0;
if (got_alternates)
return 0;
data = xmalloc(4096);
buffer.size = 4096;
buffer.posn = 0;
buffer.buffer = data;

if (get_verbosely)
fprintf(stderr, "Getting alternates list\n");

url = xmalloc(strlen(base) + 31);
sprintf(url, "%s/objects/info/http-alternates", base);

curl_easy_setopt(curl, CURLOPT_FILE, &buffer);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
curl_easy_setopt(curl, CURLOPT_URL, url);

if (curl_easy_perform(curl) || !buffer.posn) {
sprintf(url, "%s/objects/info/alternates", base);

curl_easy_setopt(curl, CURLOPT_FILE, &buffer);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
curl_easy_setopt(curl, CURLOPT_URL, url);

if (curl_easy_perform(curl)) {
return 0;
}
}

while (i < buffer.posn) {
int posn = i;
while (posn < buffer.posn && data[posn] != '\n')
posn++;
if (data[posn] == '\n') {
if (data[i] == '/') {
int serverlen = strchr(base + 8, '/') - base;
// skip 'objects' at end
char *target =
xmalloc(serverlen + posn - i - 6);
struct alt_base *newalt;
strncpy(target, base, serverlen);
strncpy(target + serverlen, data + i,
posn - i - 7);
target[serverlen + posn - i - 7] = '\0';
if (get_verbosely)
fprintf(stderr,
"Also look at %s\n", target);
newalt = xmalloc(sizeof(*newalt));
newalt->next = alt;
newalt->base = target;
newalt->got_indices = 0;
newalt->packs = NULL;
alt = newalt;
ret++;
}
}
i = posn + 1;
}
got_alternates = 1;

return ret;
}

static int fetch_indices(struct alt_base *repo)
{
unsigned char sha1[20];
char *url;
struct buffer buffer;
char *data;
int i = 0;

if (got_indices)
if (repo->got_indices)
return 0;

data = xmalloc(4096);
Expand All @@ -148,8 +226,8 @@ static int fetch_indices(void)
if (get_verbosely)
fprintf(stderr, "Getting pack list\n");

url = xmalloc(strlen(base) + 21);
sprintf(url, "%s/objects/info/packs", base);
url = xmalloc(strlen(repo->base) + 21);
sprintf(url, "%s/objects/info/packs", repo->base);

curl_easy_setopt(curl, CURLOPT_FILE, &buffer);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
Expand All @@ -160,15 +238,15 @@ static int fetch_indices(void)
return error("Unable to get pack index %s", url);
}

do {
while (i < buffer.posn) {
switch (data[i]) {
case 'P':
i++;
if (i + 52 < buffer.posn &&
!strncmp(data + i, " pack-", 6) &&
!strncmp(data + i + 46, ".pack\n", 6)) {
get_sha1_hex(data + i + 6, sha1);
setup_index(sha1);
setup_index(repo, sha1);
i += 51;
break;
}
Expand All @@ -177,26 +255,25 @@ static int fetch_indices(void)
i++;
}
i++;
} while (i < buffer.posn);
}

got_indices = 1;
repo->got_indices = 1;
return 0;
}

static int fetch_pack(unsigned char *sha1)
static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
{
char *url;
struct packed_git *target;
struct packed_git **lst;
FILE *packfile;
char *filename;

if (fetch_indices())
if (fetch_indices(repo))
return -1;
target = find_sha1_pack(sha1, packs);
target = find_sha1_pack(sha1, repo->packs);
if (!target)
return error("Couldn't get %s: not separate or in any pack",
sha1_to_hex(sha1));
return -1;

if (get_verbosely) {
fprintf(stderr, "Getting pack %s\n",
Expand All @@ -205,9 +282,9 @@ static int fetch_pack(unsigned char *sha1)
sha1_to_hex(sha1));
}

url = xmalloc(strlen(base) + 65);
url = xmalloc(strlen(repo->base) + 65);
sprintf(url, "%s/objects/pack/pack-%s.pack",
base, sha1_to_hex(target->sha1));
repo->base, sha1_to_hex(target->sha1));

filename = sha1_pack_name(target->sha1);
packfile = fopen(filename, "w");
Expand All @@ -227,7 +304,7 @@ static int fetch_pack(unsigned char *sha1)

fclose(packfile);

lst = &packs;
lst = &repo->packs;
while (*lst != target)
lst = &((*lst)->next);
*lst = (*lst)->next;
Expand All @@ -237,7 +314,7 @@ static int fetch_pack(unsigned char *sha1)
return 0;
}

int fetch(unsigned char *sha1)
int fetch_object(struct alt_base *repo, unsigned char *sha1)
{
char *hex = sha1_to_hex(sha1);
char *filename = sha1_file_name(sha1);
Expand All @@ -261,9 +338,9 @@ int fetch(unsigned char *sha1)
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, no_pragma_header);

url = xmalloc(strlen(base) + 50);
strcpy(url, base);
posn = url + strlen(base);
url = xmalloc(strlen(repo->base) + 50);
strcpy(url, repo->base);
posn = url + strlen(repo->base);
strcpy(posn, "objects/");
posn += 8;
memcpy(posn, hex, 2);
Expand All @@ -275,9 +352,7 @@ int fetch(unsigned char *sha1)

if (curl_easy_perform(curl)) {
unlink(filename);
if (fetch_pack(sha1))
return error("Tried %s", url);
return 0;
return -1;
}

close(local);
Expand All @@ -296,11 +371,30 @@ int fetch(unsigned char *sha1)
return 0;
}

int fetch(unsigned char *sha1)
{
struct alt_base *altbase = alt;
while (altbase) {
if (!fetch_object(altbase, sha1))
return 0;
if (!fetch_pack(altbase, sha1))
return 0;
if (fetch_alternates(altbase->base) > 0) {
altbase = alt;
continue;
}
altbase = altbase->next;
}
return error("Unable to find %s under %s\n", sha1_to_hex(sha1),
initial_base);
}

int fetch_ref(char *ref, unsigned char *sha1)
{
char *url, *posn;
char hex[42];
struct buffer buffer;
char *base = initial_base;
buffer.size = 41;
buffer.posn = 0;
buffer.buffer = hex;
Expand Down Expand Up @@ -368,7 +462,12 @@ int main(int argc, char **argv)
curl_easy_setopt(curl, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
#endif

base = url;
alt = xmalloc(sizeof(*alt));
alt->base = url;
alt->got_indices = 0;
alt->packs = NULL;
alt->next = NULL;
initial_base = url;

if (pull(commit_id))
return 1;
Expand Down

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