HTTP partial transfer support for object, pack, and index transfers
Signed-off-by: Nick Hengeveld <nickh@reactrix.com>
---
http-fetch.c | 185 ++++++++++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 161 insertions(+), 24 deletions(-)
492f6dfd5f0e7030fe96b3646a07a9adb1a7a2d0
diff --git a/http-fetch.c b/http-fetch.c
--- a/http-fetch.c
+++ b/http-fetch.c
@@ -13,8 +13,12 @@
#define curl_global_init(a) do { /* nothing */ } while(0)
#endif
+#define PREV_BUF_SIZE 4096
+#define RANGE_HEADER_SIZE 30
+
static CURL *curl;
static struct curl_slist *no_pragma_header;
+static struct curl_slist *no_range_header;
static char *initial_base;
@@ -82,12 +86,37 @@ void prefetch(unsigned char *sha1)
{
}
+int relink_or_rename(char *old, char *new) {
+ int ret;
+
+ ret = link(old, new);
+ if (ret < 0) {
+ /* Same Coda hack as in write_sha1_file(sha1_file.c) */
+ ret = errno;
+ if (ret == EXDEV && !rename(old, new))
+ return 0;
+ }
+ unlink(old);
+ if (ret) {
+ if (ret != EEXIST)
+ return ret;
+ }
+
+ return 0;
+}
+
static int got_alternates = 0;
static int fetch_index(struct alt_base *repo, unsigned char *sha1)
{
char *filename;
char *url;
+ char tmpfile[PATH_MAX];
+ int ret;
+ long prev_posn = 0;
+ char range[RANGE_HEADER_SIZE];
+ struct curl_slist *range_header = NULL;
+ CURLcode curl_result;
FILE *indexfile;
@@ -103,7 +132,8 @@ static int fetch_index(struct alt_base *
repo->base, sha1_to_hex(sha1));
filename = sha1_pack_index_name(sha1);
- indexfile = fopen(filename, "w");
+ snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
+ indexfile = fopen(tmpfile, "a");
if (!indexfile)
return error("Unable to open local file %s for pack index",
filename);
@@ -113,12 +143,35 @@ static int fetch_index(struct alt_base *
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, no_pragma_header);
- if (curl_easy_perform(curl)) {
+ /* If there is data present from a previous transfer attempt,
+ resume where it left off */
+ prev_posn = ftell(indexfile);
+ if (prev_posn>0) {
+ if (get_verbosely)
+ fprintf(stderr,
+ "Resuming fetch of index for pack %s at byte %ld\n",
+ sha1_to_hex(sha1), prev_posn);
+ sprintf(range, "Range: bytes=%ld-", prev_posn);
+ range_header = curl_slist_append(range_header, range);
+ curl_easy_setopt(curl, CURLOPT_HTTPHEADER, range_header);
+ }
+
+ /* Clear out the Range: header after performing the request, so
+ other curl requests don't inherit inappropriate header data */
+ curl_result = curl_easy_perform(curl);
+ curl_easy_setopt(curl, CURLOPT_HTTPHEADER, no_range_header);
+ if (curl_result != 0) {
fclose(indexfile);
return error("Unable to get pack index %s", url);
}
fclose(indexfile);
+
+ ret = relink_or_rename(tmpfile, filename);
+ if (ret)
+ return error("unable to write index filename %s: %s",
+ filename, strerror(ret));
+
return 0;
}
@@ -299,6 +352,12 @@ static int fetch_pack(struct alt_base *r
struct packed_git **lst;
FILE *packfile;
char *filename;
+ char tmpfile[PATH_MAX];
+ int ret;
+ long prev_posn = 0;
+ char range[RANGE_HEADER_SIZE];
+ struct curl_slist *range_header = NULL;
+ CURLcode curl_result;
if (fetch_indices(repo))
return -1;
@@ -318,7 +377,8 @@ static int fetch_pack(struct alt_base *r
repo->base, sha1_to_hex(target->sha1));
filename = sha1_pack_name(target->sha1);
- packfile = fopen(filename, "w");
+ snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
+ packfile = fopen(tmpfile, "a");
if (!packfile)
return error("Unable to open local file %s for pack",
filename);
@@ -327,14 +387,36 @@ static int fetch_pack(struct alt_base *r
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite);
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, no_pragma_header);
-
- if (curl_easy_perform(curl)) {
+
+ /* If there is data present from a previous transfer attempt,
+ resume where it left off */
+ prev_posn = ftell(packfile);
+ if (prev_posn>0) {
+ if (get_verbosely)
+ fprintf(stderr,
+ "Resuming fetch of pack %s at byte %ld\n",
+ sha1_to_hex(target->sha1), prev_posn);
+ sprintf(range, "Range: bytes=%ld-", prev_posn);
+ range_header = curl_slist_append(range_header, range);
+ curl_easy_setopt(curl, CURLOPT_HTTPHEADER, range_header);
+ }
+
+ /* Clear out the Range: header after performing the request, so
+ other curl requests don't inherit inappropriate header data */
+ curl_result = curl_easy_perform(curl);
+ curl_easy_setopt(curl, CURLOPT_HTTPHEADER, no_range_header);
+ if (curl_result != 0) {
fclose(packfile);
return error("Unable to get pack file %s", url);
}
fclose(packfile);
+ ret = relink_or_rename(tmpfile, filename);
+ if (ret)
+ return error("unable to write pack filename %s: %s",
+ filename, strerror(ret));
+
lst = &repo->packs;
while (*lst != target)
lst = &((*lst)->next);
@@ -351,14 +433,29 @@ int fetch_object(struct alt_base *repo,
char *filename = sha1_file_name(sha1);
unsigned char real_sha1[20];
char tmpfile[PATH_MAX];
+ char prevfile[PATH_MAX];
int ret;
char *url;
char *posn;
+ int prevlocal;
+ unsigned char prev_buf[PREV_BUF_SIZE];
+ ssize_t prev_read = 0;
+ long prev_posn = 0;
+ char range[RANGE_HEADER_SIZE];
+ struct curl_slist *range_header = NULL;
+ CURLcode curl_result;
+
+ snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
+ snprintf(prevfile, sizeof(prevfile), "%s.prev", filename);
+ unlink(prevfile);
+ rename(tmpfile, prevfile);
+ unlink(tmpfile);
+
+ local = open(tmpfile, O_WRONLY | O_CREAT | O_EXCL, 0666);
- snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX",
- get_object_directory());
+ /* Note: if another instance starts now, it will turn our new
+ tmpfile into its prevfile. */
- local = mkstemp(tmpfile);
if (local < 0)
return error("Couldn't create temporary file %s for %s: %s\n",
tmpfile, filename, strerror(errno));
@@ -386,8 +483,56 @@ int fetch_object(struct alt_base *repo,
curl_easy_setopt(curl, CURLOPT_URL, url);
- if (curl_easy_perform(curl)) {
- unlink(filename);
+ /* If a previous temp file is present, process what was already
+ fetched. */
+ prevlocal = open(prevfile, O_RDONLY);
+ if (prevlocal != -1) {
+ do {
+ prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
+ if (prev_read>0) {
+ if (fwrite_sha1_file(prev_buf,
+ 1,
+ prev_read,
+ NULL) == prev_read) {
+ prev_posn += prev_read;
+ } else {
+ prev_read = -1;
+ }
+ }
+ } while (prev_read > 0);
+ close(prevlocal);
+ }
+ unlink(prevfile);
+
+ /* Reset inflate/SHA1 if there was an error reading the previous temp
+ file; also rewind to the beginning of the local file. */
+ if (prev_read == -1) {
+ memset(&stream, 0, sizeof(stream));
+ inflateInit(&stream);
+ SHA1_Init(&c);
+ if (prev_posn>0) {
+ prev_posn = 0;
+ lseek(local, SEEK_SET, 0);
+ }
+ }
+
+ /* If we have successfully processed data from a previous fetch
+ attempt, only fetch the data we don't already have. */
+ if (prev_posn>0) {
+ if (get_verbosely)
+ fprintf(stderr,
+ "Resuming fetch of object %s at byte %ld\n",
+ hex, prev_posn);
+ sprintf(range, "Range: bytes=%ld-", prev_posn);
+ range_header = curl_slist_append(range_header, range);
+ curl_easy_setopt(curl, CURLOPT_HTTPHEADER, range_header);
+ }
+
+ /* Clear out the Range: header after performing the request, so
+ other curl requests don't inherit inappropriate header data */
+ curl_result = curl_easy_perform(curl);
+ curl_easy_setopt(curl, CURLOPT_HTTPHEADER, no_range_header);
+ if (curl_result != 0) {
return -1;
}
@@ -403,20 +548,11 @@ int fetch_object(struct alt_base *repo,
unlink(tmpfile);
return error("File %s has bad hash\n", hex);
}
- ret = link(tmpfile, filename);
- if (ret < 0) {
- /* Same Coda hack as in write_sha1_file(sha1_file.c) */
- ret = errno;
- if (ret == EXDEV && !rename(tmpfile, filename))
- goto out;
- }
- unlink(tmpfile);
- if (ret) {
- if (ret != EEXIST)
- return error("unable to write sha1 filename %s: %s",
- filename, strerror(ret));
- }
- out:
+ ret = relink_or_rename(tmpfile, filename);
+ if (ret)
+ return error("unable to write sha1 filename %s: %s",
+ filename, strerror(ret));
+
pull_say("got %s\n", hex);
return 0;
}
@@ -505,6 +641,7 @@ int main(int argc, char **argv)
curl = curl_easy_init();
no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
+ no_range_header = curl_slist_append(no_range_header, "Range:");
curl_ssl_verify = getenv("GIT_SSL_NO_VERIFY") ? 0 : 1;
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
-
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