write_entry: avoid reading blobs in CE_RETRY case

When retrying a delayed filter-process request, we don't need to send the blob to the filter a second time. However, we read it unconditionally into a buffer, only to later throw away that buffer. We can make this more efficient by skipping the read in the first place when it isn't necessary. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Oct 9, 2017 at 13:48 UTC c602d3a9897a408ce0db543860d472332f79d045
1 file changed +14 -11
entry.c
+14 -11
@@ -240,6 +240,7 @@ static int write_entry(struct cache_entry *ce,
240 char *path, const struct checkout *state, int to_tempfile)
241 {
242 unsigned int ce_mode_s_ifmt = ce->ce_mode & S_IFMT;
243 + struct delayed_checkout *dco = state->delayed_checkout;
244 int fd, ret, fstat_done = 0;
245 char *new;
246 struct strbuf buf = STRBUF_INIT;
@@ -261,10 +262,19 @@ static int write_entry(struct cache_entry *ce,
262 switch (ce_mode_s_ifmt) {
263 case S_IFREG:
264 case S_IFLNK:
264 - new = read_blob_entry(ce, &size);
265 - if (!new)
266 - return error("unable to read sha1 file of %s (%s)",
267 - path, oid_to_hex(&ce->oid));
265 + /*
266 + * We do not send the blob in case of a retry, so do not
267 + * bother reading it at all.
268 + */
269 + if (ce_mode_s_ifmt == S_IFREG && dco && dco->state == CE_RETRY) {
270 + new = NULL;
271 + size = 0;
272 + } else {
273 + new = read_blob_entry(ce, &size);
274 + if (!new)
275 + return error("unable to read sha1 file of %s (%s)",
276 + path, oid_to_hex(&ce->oid));
277 + }
278
279 if (ce_mode_s_ifmt == S_IFLNK && has_symlinks && !to_tempfile) {
280 ret = symlink(new, path);
@@ -279,14 +289,7 @@ static int write_entry(struct cache_entry *ce,
289 * Convert from git internal format to working tree format
290 */
291 if (ce_mode_s_ifmt == S_IFREG) {
282 - struct delayed_checkout *dco = state->delayed_checkout;
292 if (dco && dco->state != CE_NO_DELAY) {
284 - /* Do not send the blob in case of a retry. */
285 - if (dco->state == CE_RETRY) {
286 - free(new);
287 - new = NULL;
288 - size = 0;
289 - }
293 ret = async_convert_to_working_tree(
294 ce->name, new, size, &buf, dco);
295 if (ret && string_list_has_string(&dco->paths, ce->name)) {